Preface
This Activity Report covers scientific and technological activities carriedout using the UVSOR-III Synchrotron in FY2021 (April 2021 - March 2022).
We present scientific examples of how the users study at the UVSOR
Synchrotron Facility.
The present UVSOR-III Synchrotron is one of the most advanced lowenergy SR facilities of the 3rd generation SR in the world and is now oneof the critical resources to accelerate the investigation of molecularscience. The UVSOR-III Synchrotron has a small electron storage ring but
has powerful 6-undulator beamlines (3 VUV and 3 in-vacuum soft X-ray
undulators) with 8-dipole beamlines. We continue improving and upgrading
our micro- and nano-scale photoabsorption and photoemission approaches
and in situ/operando measurements in the IR, VUV, and soft X-ray regions, based on our strategic international
collaboration program in molecular science. We are grateful to all the people who use our facility and support
our efforts.
UVSOR operates for 40 weeks/year (ca. 2,200 h user time), accepts ~230 proposals, about ~600 individual
researchers counting total ~4,000 people*day/year. Most users stay for one or two weeks for experimenting. To
continue high-level achievements in science and technology at the UVSOR-III Synchrotron, our in-house staff
is constantly committed to maintaining and improving high-performance accelerators and beamlines. Research
activity has been affected by COVID-19 worldwide, however, the daily life of scientists seems to be renovated.
Of course, it has impacted overseas researchers who cannot travel to Japan. We support some of their researchby doing the experiment on their behalf.
In terms of personnel, Assitant professors, Takuji Ohigashi and Masaki Fujimoto left UVSOR. They will kindly
support the beamlines by cross-appointment contract in FY2022. The support office staff, Hisayo Hagiwara
retired, who has been dedicated as a secretary for a quite long time since the early days of UVSOR.
On the experimental side, technology development will not stop, hence we will make a progress on theimaging-related techniques to inspire advanced molecular science. We have started to construct the new
endstation at the undulator-based soft X-ray beamline BL6U since 2020. The new instrumentation of thephotoelectron momentum microscope is developing and you may see the final whole picture of the apparatus in
FY2022, which consists of a double-hemispherical analyzer with spin detector. In the beamline BL1U, we haveconducted in developing the novel light sources, including pulsed-γ ray and their use for the measurements.
To optimize the high-power laser light to UVSOR-III for versatile use, we arranged the endstation layout of
BL1U. In FY2022, we will test the new orbit trajectory for doing the γ-ray experiments daily to avoid affecting
other beamlines. The advanced SR-related instrument will offer opportunities in characterizing the electronic
structure of surface atomic sites, thin films, molecular adsorbates, bulk crystals, and so on.
We have discussed the possibility to construct the post-UVSOR-III as a long-term plan for sustainable
development since 2019. We look forward to receiving your feedback and suggestions on the continuing
evolution of the UVSOR Synchrotron Facility. And we hope many users will perform excellent work by fully
utilizing the UVSOR-III Synchrotron as a unique international hub for the SR research in advanced molecularscience.

April 2022
Satoshi Kera
Director of the UVSOR Synchrotron Facility

News
2021
The Commendation for Science and Technology by the Minister of
Education, Culture, Sports, Science and Technology (Outstanding
Support for Research Award) Given to Mr. Eiken Nakamura
Mr. Eiken Nakamura, Chief

Engineerin UVSOR Synchrotron Facility, received the Commendationfor Science and Technology by the Minister of Education, Culture, Sports, Science and Technology(Outstanding Support for Research Award) for "Development of an L-shaped slit for synchrotron
radiation and its contribution to a design for beamlines with insertion light sources." This award isgiven to persons who made outstanding achievements in research and development in science andtechnology in order to raise the level of science and technology in Japan.

News
2021
The Outstanding Presentation Award of the 64th Annual Meeting of theJapanese Society of Radiation Chemistry Given to Dr. Yoshitaka TairaDr. Yoshitaka Taira, Associate Professor in UVSOR Synchrotron Facility, received the Outstanding
Presentation Award of the 64th Annual Meeting of the Japanese Society of Radiation Chemistry forhis presentation entitled “Development of gamma-ray induced positron annihilation spectroscopy
at UVSOR-III.” The gamma-ray induced positron annihilation spectroscopy enables defect analysisof the entire bulk sample with a thickness of several cm, which was difficult to measure with theconventional method using a positron radiation source.

The 2021 Young Presentation Award of the Young Researchers Associationof the Japan Beam Physics Club given to Mr. Ryohei Yamamoto
Mr. Ryohei Yamamoto received the Young Presentation Award of the Young Researchers
Association of the Japan Beam Physics Club 2021 for his presentation entitled “Development of
gamma-ray-induced positron age-momentum correlation measurement method in UVSOR-III”. In
UVSOR-III, gamma-ray induced positron annihilation spectroscopy by ultrashort pulse gamma rays is
being developed.

StaffUVSOR ACTIVITY REPORT 2021
Preface
S. KeraNews
I. Organization and Staff List

1

II. Current Status of Light Sources and Beamlines

7

Light Sources in 2021（Y. Taira）

9

Beamlines in 2021（F. Matsui）

12

III. Research Activities
III-1. Accelerators and Instruments
Improvement of Image Quality of Selective Isotope 3DCT in UVSOR-BL1U [1U]

H. Ohgaki, K. Ali, H. Zen, T. Kii, T. Hayakawa, T. Shizuma, M. Fujimoto,Y. Taira and M. Katoh

31
00
33

Photon Counting Experiments of Young’s Double-Slit Interference
Using Undulator Vortex Radiation [1U]00
34

Development Mass Production Facilities of Nuclear Emulsion Films[Others]

00
35

S. Wada, H. Ohta, A. Mano, M. Fujimoto and M. Katoh

I. Usuda, H. Rokujo and M. Nakamura

Laser Pulse Shaping and Transport at UVSOR-III [1U]

Y. Takashima, A. Mano, G. Jang, Y. Taira, M. Fujimoto, Y. Okano and M. Katoh

Revival of UVSOR-FEL and Gamma Ray Generation by Intra-cavity
Laser Compton Scattering [1U]
H. Zen, J. Yamazaki, M. Fujimoto, K. Hayashi, H. Ohta, Y. Taira and M. Katoh

36
00
37

Evaluation of Analyzing Power of Gamma-ray Polarimeter [1U]00
38

Development of Gamma ray Induced Positron Annihilation
Spectroscopy [1U]

00
39

S. Endo, T. Shizuma, H. Zen, Y. Taira, K. Sugita, O. Mohamed, S. Kawamura, R. Abe,T. Okudaira, M. Kitaguchi and H. M. Shimizu

Y. Taira, K. Sugita, R. Yamamoto, Y. Okano and T. Hiradei00Single Electron Storage at UVSOR-III [1U]

R. Shinomiya, M. Shimada, H. Miyauchi, M. Fujimoto and M. Katoh

40

Exploring Novel Application of Undulator Radiation Based on
Interferometric Technique [1U]41

Calibration of CMOS Sensor with Reflective-type Flux Reduction
System [2A]

42

Photon Energy Resolutions of BL3B Evaluated by Appearance
Energy Measurements of Xe+ Ions [3B]

43

BL4B Usage for Developing the Photoelectron Spectroscopy Endstation for Organic Materials [4B]44

K. Kato, M. Shimada, H. Miyauchi, A. Mano and M. Katoh

N. Narukage

H. Iwayama

K. Fukutani, H. Iwayama, F. Matsui and S. Kera

Development of High Efficiency Liquid Cell in Total Electron Yield
Using Atomically-thin Graphene [4B]
I. Mitsuishi, K. Kashiwakura, Y. Niwa, T. Ogawa, Y. Tawara, R. Kitaura,
P. Solís-Fernández, K. Kawahara, H. Ago, T. Taniguchi, K. Nomoto, H. Kodaka,
T. Horigome, E. Nakamura, H. Iwayama, M. Nagasaka and K Tanaka

45

Development of a Fluorescence Polarimeter in Extreme Ultraviolet
Region [5B]46

Measurement of a Detection Efficiency of High-sensitivity
Microchannel Plates with Tapered Pores [5B]47

T. Kaneyasu, K. Hosaka and J. Adachi

S. Matoba, H. Iwayama and T. Kaneyasu

Study on the Source of Photon-Energy Drift of BL5B [5B]
H. Zen, E. Nakamura, K. Hayashi and K. Tanaka

48

Complex Refractive Index Measurement by Reflectance Spectra in
Different Polarization Configurations [7B]49

III-2. Materials Sciences

51

M. Horiba, K. Fukui, K. Yamamoto and T. Saito

Study on Defects in Iron Formed under Hydrogen
Embrittlement Environment Using In-Situ Measurement
Technique of Gamma-Ray Induced Positron Annihilation
Lifetime Spectroscopy [1U]
A. Yabuuchi, T. Hirade, M. Fujinami, R. Awaji, N. Oshima, K. Takai,
K. Sugita and Y. Taira

Momentum Microscope Study of a Kagome
Superconductor CsV3Sb5 [6U]

00
53
00

T. Kato, K. Nakayama, Y. Li, Z. Wang, Y. Yao, F. Matsui, T. Takahashi and
T. Sato

54
00

ii

00

Probing Vacancy-type Defects in Ce:LuAG Scintillators by GiPALS
Experiment and DFT Calculation [1U]

55

LCS-gamma Induced Positron Annihilation Study for the Dynamics
of Defect Behavior in Bulk Materials [1U]56

Effect of the Particle Size on the Positron Annihilation Lifetime andRelative Intensity of CeO2 Nanoparticles [1U]57

Mo LIII-Edge XANES Study of Highly Active MoCx Species in Mo-V
Modified H-MFI Catalysts for Methane Dehydroaromatization [2A]

58

Evaluation of the Electronic State of MgO by NEXAFS Spectroscopy
[2A]

59

Sintering Behavior of Mg-Doped Hydroxyapatite Nano Particles
[2A]

60

M. Kitaura, Y. Taira and S. Watanabe

F. Hori, S. Araki, K. Sugita and Y. Taira

S. Dohshi, K. Maeda, Y. Taira, H. Toyokawa and T. Hirade

K. Kuramochi, R. Yamazaki, Y. Sonobe, Y, Uchimura and H. Aritani

E. Kobayashi, K. K. Okudaira, S. Yoshioka and A. Inoishi

H. Murata, R. Kawanabe and A. Nakahira

Local Structure around Mg in Mg1-xNixAl2O4 [2A]

S. Yoshioka , K. Yasuda, S. Matsumura, E. Kobayashi and K. Okudaira

61

Local Structure Investigations of Zn in ZnAl2O4 Induced on Swift
Heavy Ion Irradiations [2A]

62

S. Yoshioka, K. Yasuda, S. Matsumura, E. Kobayashi and K. Okudaira

UPS Spectroscopy of TFP Doped P3HT/PCBM Thin Films [2B]
K. K. Okudaira and Y. Hoshi

63

Valence and In-gap states of a Polyethylene Model Oligomer, C44H90,
Film Studied by Conventional and High-Sensitivity Photoelectron
Spectroscopy [2B, 7U]

64

Structure Analysis on Helical Nanofilament of B4 Phase of Bentcore Liquid Crystals Mixed with Rod-like Cholesteric Liquid Crystals
by Resonant Soft X-ray Scattering (RSoXS) at UVSOR [3U]65

R. Nakazawa, M. Yoshizawa, S. Kera and H. Ishii

Y. Takanishi, F. Araoka and H. Iwayama

Evaluation of Fluorescence Lifetimes of Wavelength Shifting Fibers
for High-energy Particle Experiments [3B]
K. Shintate, R. Abe, R. Ishiyama, T. Naitou, S. Nakamura, S. Sakano, J. Ohashi,
Y. Tajima and H. Y. Yoshida

66

Thermoluminescence of LuAG Thick Film Scintillators Prepared via
Chemical Vapor Deposition Process [3B]67

Temperature Dependence of Photoluminescence Properties of
Li2HfI6 [3B]68

S. Matsumoto, S. Kurosawa and A. Ito

C. Fujiwara, S. Kurosawa and A. Yamaji

iii

Reflectivity Spectra of Sm0.9Ca0.1S in Vacuum Ultra Violet Region[3B]
Y. Yokoyama, K. Kishida, F. Matsunaga, M. Kanou, K. Takano, Y. Okamoto,
H. S. Suzuki, K. Takehana, Y. Imanaka and K. Takenaka

Optical Investigation on Fluoro-olefins in Vacuum-Ultraviolet for
New Refrigerant Gas Development [3B]
K. Yamanoi, Y. Sakata, H. Iwayama, Y. Hasumoto, O. Yamamoto and M. Noumi

69

70

Absorption Bands of Tl+ Centers in CsI-based Ternary Crystals [3B]71

Photoluminescence Properties of Cs2ZrI6 [3B]
S. Kodama and S. Kurosawa

72

Structural Analysis of Unvulcanized Rubber by Scanning
Transmission X-ray Microscopy [4U]73

C-K Edge Spectra of Bound-rubber Structure in SBR Materials with
Filler and/or Reagents [4U]74

S. Ito and T. Kawai

T. Ohigashi, F. Kaneko, H. Yuzawa and H. Kishimoto

T. Ejima and Y. Tamura

Analysis of Materials for Secondary Batteries by STXM [4U]E. Hosono, D. Asakura, H. Yuzawa and T. Ohigashi

75

Probing the Electronic Structure of Ni-Co Binary Oxide/Graphene
Nanocomposites as Supercapacitor Electrodes by Scanning
Transmission X-ray Microscope [4U]76

Development of Reflection XMCD Measurement Setup for theInvestigation of Inner Structures of Magnetic Thin Films at UVSOR
BL4B [4B]

77

H. W. Chang, T. C. Huang, T. Ohigashi, C. H. Chuang, Y. C. Tsai, C. L. Dong andW. F. Pong

K. Yamamoto, H. Iwayama, O. Ishiyama and T. Yokoyama

Dirac Fermions and Topological Phase Transition in X Mg2Bi2 (X = Ba
and Sr) [5U]
D. Takane, Y. Kubota, K. Nakayama, T. Kawakami, S. Souma, K. Sugawara, S. Ideta,
K. Tanaka, T. Takahashi, K. Segawa and T. Sato

Band-structure Reconstruction of Ca3Ru2O7 Induced by K Adsorption[5U]
M. Horio, T. Wada, V. Granata, R. Fittipaldi, A. Vecchione, K. Tanaka, I. Matsuda and
J. Chang

Quadrupole Electronic Structure in Mn3-xGa Studied by Angleresolved Photoemission Spectroscopy [5U]
J. Okabayashi, Y. Miura, K. Tanaka, K. Z. Suzuki and S. Mizukami

Change of the Fermi Surface of Bi2Sr2CaCu2O8+δ Observed by ARPES[5U]
Y. Tsubota, S. Kumar, Y. Miyai, K. Tanaka, S. Ishida, H. Eisaki, S. Nakagawa,T. Kashiwagi, M. Arita, K. Shimada and S. Ideta

iv

78

79

80

81

CDW-induced Electronic Reconstruction in a Kagome Metal KV3Sb5[5U]
T. Kato, K. Nakayama, T. Kawakami, A. Moriya, Yongkai Li, Z. Wang, S. Ideta,
K. Tanaka, T. Takahashi, Y. Yao and T. Sato

82

Electronic Structure of VNb3S6: a Transition-metal Intercalated
NbS2 [5U]83

Angle-resolved Photoemission Study of Zr3SnC2 [5U]84

Fermi Surface Measurements of TiSe2 with the CDW Transition [5U]
S. Tanaka, K. Ueno and K. Tanaka

85

Temperature Dependence of Electronic Structure in Pb-doped
La(O,F)BiS2 Superconductor [5U]86

Evaluation of Self-Energy in Overdoped Bi2201 by Angle-Resolved
Photoemission Spectroscopy [5U]87

Multi-atom Resonance Photoemission from the Valence Band of
TiSe2 [6U]88

Temperature-dependent Electronic Structure of η-Mo4O11 Revealedby Photoelectron Momentum Microscopy [6U]89

Characterization of CVD Graphene on Ir(111)/α-Al2O3(0001) by
Photoelectron Momentum Microscope [6U]90

Vibrational Spectroscopy of Pentacene Single Crystals in the Mid to
Far Infrared Region and its Temperature Dependence [6B]91

Spectral Evidence of Current-Induced Local-to-Nonlocal Transitionof SmS [6B]92

Structural Analysis of Fiber Biomaterials by Synchrotron-Radiation
Infrared Microspectroscopy [6B]93

M. Horio, T. Wada, S. Okazaki, K. Tanaka, T. Sasagawa and I. Matsuda
T. Ito, M. Mita, D. Pinek, M. Nakatake, K. Tanaka and T. Ouisse

N. Kataoka, L. Y. Jun, T. Setoguchi, S. Demura and T. Yokoya

Y. Miyai, S. Kumar, T. Kurosawa, M. Oda, S. Ideta and K. Shimada

S. Tanaka, K. Ueno, K. Fukutani and F. Matsui

T. Kobayashi, E. Iwamoto, K. Sakamoto, F. Matsui and S. Suga

E. Hashimoto, K. Tamura, H. Yamaguchi, F. Matsui and S. Koh

J. Miyamoto, A. Sugiyama, K.Yamauchi and Y. Nakayama

H. Watanabe, S. Tatsukawa, K. Imura, H. S. Suzuki, N. K. Sato and S. Kimura

T. Kawasaki, F. Teshima and K. Tanaka

Low-energy ARPES Study of Iron-chalcogenide High-temperature
Superconductors [7U]

K. Nakayama, T. Kato, A. Moriya, F. Nabeshima, N. Shikama, T. Ishikawa, Y. Sakishita,
S. Ideta, K. Tanaka, T. Takahashi, A. Maeda and T. Sato

Elucidations of Electronic Structure and the Many-body Interactionsof Organic Molecular Materials [7U]
K. Fukutani, Y. Hasegawa, M. Murakami, D. Okaue, K. Fukui, H. Ishii, K. Tanaka and
S. Kera

v

94

95

00
Dirac-cone and Saddle-point Energy Bands in a Kagome
Superconductor A V3Sb5 [7U]

K. Nakayama, T. Kato, Y. Li, Z. Wang, K. Tanaka, T. Takahashi, Y. Yao and T. Sato

Angle-resolved Photoemission Study of TPP[FePc(CN)2]2 [7U]
T. Ito, T. Hoshina, K. Tanaka, M. Matsuda and N. Hanasaki

Relationship between Chemical Pressure Effect and Electronic
Structure in R1-xCexOBiS2 (R =Nd, La) [7U]
N. Kataoka, T. Wakita, Y. Hanada, M. Nagao and T. Yokoya

96
00
97
00
98

Photoluminescence Properties of Cs2ZnCl4 and Cs3ZnCl5 with
Vacuum Ultraviolet Excitation [7B]00
99

Investigation of Gamma-ray-irradiated Oxide Glasses for Deep
Ultraviolet Detector with High Efficiency [7B]

10000

III-3. Chemistry

103

K. Takahashi, M. Koshimizu, Y. Fujimoto and K. Asai

T. Shimizu, K. Shinohara, D. Umeno, K. Yamanoi and N. Sarukura

Solvent-Induced Transition of Polymorphological ChiralSupermolecular Architectures in Bent-Core Liquid
Crystal Dimer/Nematic Binary Mixtures as Studied by
Resonant Soft X-ray Scattering (RSoXS) at UVSOR [3U]

F. Araoka, Y. Takanishi, K. V. Le and H. Iwayama

Energy-Dependence of Photoelectron Circular Dichroism of Chiral
Molecules [1U]

H. Kohguchi, Y. Hikosaka, T Kaneyasu, S. Wada, H. Ohta, M. Fujimoto, M. Katoh and
Y-I. Suzuki

Photoionization of Atoms by Double-pulsed Radiation from a
Tandem-Undulator [1U]

T. Kaneyasu, Y. Hikosaka, S. Wada, M. Fujimoto, H. Ota, H. Iwayama and M. Katoh

Electronic State Changes of Cu Nanoparticles on Rutile TiO2(110)by CO Exposure [2B]

K. Mitsuhara, K. Ide, H. Takatani, Y. Hasegawa and M. Takizawa

00
105
00
106
00
107
00
108

X-ray Absorption Spectra of Aqueous Cellobiose [3U]

T. Sasaki and D. Akazawa

00
109

X-ray Absorption Spectroscopy Study of 4-MBA on Gold Surfaces
[3U]

00
110

Resonant Soft X-ray Scattering Equipment Evaluated by Chicken
Leg’s Collagens and 100-nm Silica Nanoparticles [3U]111

Oxygen K-edge X-ray Absorption Spectroscopy of Aqueous Dimethyl
Sulfoxide Solutions at Different Concentrations [3U]112

I. Sakaida, S. Ohno, M. Nagasaka

H. Iwayama, F. Araoka and Y. Takanishi

M. NagasakaviCarbon K-edge X-ray Absorption Spectroscopy of Aqueous Ethanol
Solutions at Different Concentrations [3U]113

The C–Si Bond Length of Organosilicon Compounds in Organic
Solvent Probed by Carbon K-edge X-ray Absorption Spectroscopy
[3U]

114

Direct Observation of a High Valent Oxo Species of a μ-NitridoBridged Iron Phthalocyanine Dimer Deposited on a Graphite Surface
in Aqueous Solution by Soft X-ray Absorption Spectroscopy [3U]115

Soft X-ray Absorption of Photocatalysts for Artificial
Photosynthesis: A Feasibility Study under Ultraviolet Light
Irradiation [3U]116

Variation of the Resonance Band of Water in Soft X-Ray Absorption
Spectra of Aqueous Acetone Solutions [3U]117

Oxygen K-edge X-ray Absorption Spectroscopy of Molecular Oxygen
Adsorbed on Lipid Bilayers [3U]118

Position-Sensitive Soft X-ray Absorption Spectroscopy of Carbonbased Catalysts for Redox Flow Battery [4U]

119

Investigating Electrochemical Reactivity on Ni(OH)2 Electrocatalyst
in Alkaline Electrolytes [4U]120

Quadruple Auger Decay of the Xe 3d5/2 Core-Hole State Investigatedby Multielectron−Ion Coincidence Spectroscopy [4B]121

Ion Branching Ratio for the Xe 4p Auger Decay Studied by
Photoelectron−Ion Coincidence Spectroscopy [4B]122

Electronic Structure Analysis of Ni Complex Bearing N -Heterocyclic
Carbene Ligand Using Ni L2,3-edge X-ray Absorption Spectroscopy
[4B]

123

M. Nagasaka, M. Bouvier, H. Yuzawa and N. Kosugi

S. Okumura, M. Nagasaka, H. Takaya and Y. Uozumi

Y. Yamada and M. Nagasaka

H. Onishi, T. Hirai, N. Ichikuni and T. Yoshida

K. Okada, C. Sugahara, H. Iwayama and M. Nagasaka

F. Kumaki, M. Nagasaka, Y. Kinjo, R. Tero, Y. Okano, M. Fujimoto and J. Adachi

E. Hosono, D. Asakura, H. Yuzawa, T. Ohigashi and A. Ohira

J. Kim T. Ohigashi and J. Lim

Y. Hikosaka

Y. Hikosaka

Y. Uetake, Y. Yamauchi and Y. Hoshimoto

Evaluation of Absorption Stability of a Hydrogen Absorption Cell
[5B]
M. Taguchi, M. Kuwabara, T. Katsumata, M. Tateyama, K. Yoshioka, Y. Suzuki,
K. Goda, K. Inoue, A. Tomioka and A. Yamazaki

vii

124

00

III-4. Surface, Interface and Thin Films

125

Polarization-dependent Photoelectron Intensity in Cadoped Graphene [5U]00
127

Elucidation of the Function of Adsorbed Anions on the Surface of
Cobalt Catalysts by Operando Observation [3U]00
128

S. Ichinokura, K. Tokuda, K. Tanaka and T. Hirahara

K. Harada, S. Tsunekawa, A. Sakai, M. Nagasaka and M. YoshidaEvaluation of Interface Between Sapphire Substrate and UVEmitting Zinc Aluminate Phosphor Thin Films [3B]

H. Kominami, M. Endo, T. Kawashima, N. Sonoda, K. Inoue, N. Uesugi, K. Nie,
A. Adachi, R. Ishihara, Y. Kamoi, A. Dorokhina and S.Kurosawa

Application of Atomically-thin Graphene to X-ray Astronomy: Soft
X-ray Transmission Measurements [4U]
I. Mitsuishi, K. Kashiwakura, Y. Niwa, T. Ogawa, M. Hirota, Y. Tawara, R. Kitaura,
P. Solís-Fernández, K. Kawahara, H. Ago, T. Taniguchi, K. Nomoto, H. Kodaka,
T. Ohigashi, H. Yuzawa and K. Tanaka

Annealing Effect on the Vacuum Ultraviolet Transmission Spectrumof Amorphous Selenium [4B]
K. Hayashi

Magnetic Properties of CoPc/γ’-Fe4N Organic-inorganic HybridInterface [4B]
T. Miyamachi, H. Ono, Y. Umeda, K. Yamamoto, O. Ishiyama, T. Yokoyama and
M. Mizuguchi

Enhancement of the Perpendicular Magnetic Anisotropy inN-surfactant Assisted FeCo Ordered Alloy Thin Films [4B]

T. Miyamachi, Y. Umeda, H. Ono, K. Yamamoto, O. Ishiyama, T. Yokoyama and
M. Mizuguchi

ARPES from Si{111} Facet Surfaces on Three-dimensional Lined
Structures on Si(001) Substrates [5U]

K. Hattori, L. N. Pamasi, Y. Sakai, H. Yang, T. Shimizu, Y. Ida, W. Imayama, S. Tanaka,
A. N. Hattori, S. Suga and K. Tanaka

Electronic Structure of K Adsorbed SmS Surface [5U]

T. Nakamura, T. Nakaya, H. Sugihara, K. Tanaka, K. Imura, H. S. Suzuki, N. K. Sato and
S. Kimura

00
129
00
130

131

132

133

134

135

Explorations for Spontaneously Formed Excitons in Narrow-gap
Semiconductors and Semimetals [5U]136

X-ray Absorption Spectroscopy Measurements of Au/Fe/MgO
Sandwich Structure Sample for Study of Soft X-ray Second
Harmonic Generation [5B]137

Bromine Doping to Perylene Monolayer on Au(110): Photoelectron
Momentum Microscopy [6U]138

K. Fukutani, M. Murakami, C.I. Kwon, J. S. Kim, K. Tanaka and S. Kera

T. Sumi, M. Horio, X. Zhang, T. Kato and I. Matsuda

O. Endo, F, Matsui, S. Kera, W. -J. Chun, M. Nakamura, K. Amemiya and H. Ozaki

viii

High-resolution Photoelectron Momentum Microscope Study on theElectronic Structure of Charge-density-wave Material [6U]

139

Twin-domain Boundary and Monoatomic Step of Graphite Surface
Imaged by Photoelectron Momentum Microscopy [6U]140

Development of the Fabrication System for the μm-scale Ultra-thinFilm at BL6U [6U]141

High-resolution Angle-resolved Photoemission Study on MnBi2Se4/
Bi2Se3/MnBi2Se4 Sandwich Structure [7U]142

K. Fukutani, S. Tanaka, F. Matsui and S. Kera

F. Matsui, Y. Okano, H. Matsuda, T. Yano, E. Nakamura, S. Kera and S. Suga

T. Nakamura, F. Matsui and S. Kimura

R. Fukushima, S. Ichinokura, K. Tanaka and T. Hirahara

Observation of Electronic Structure of YbCu2/Cu(111) Surface Alloy[7U]
H. Sugihara, T. Nakamura, Y. Chen, K. Tanaka and S. Kimura

143
00Electrochemical Attenuated Total Reflectance Ultraviolet (EC-ATRUV) Spectroscopy Applied for Organic Semiconductor / Ionic Liquids
Interface [7B]144
00

III-5. Life, Earth and Planetary Sciences

147

I. Tanabe, Y. Hanamori and K. Fukui

Hayabusa2 Returned Samples: Unique and Pristine
Record of Solar System Materials from Asteroid Ryugu[4U]

M. Ito, N. Tomioka, M. Uesugi, A. Yamaguchi, N. Imae, N. Shirai,
T. Ohigashi, M. Kimura, M-C. Liu, R. C. Greenwood, K. Uesugi, A. Nakato, K. Yogata,
H. Yuzawa, Y. Kodama, A. Tsuchiyama, M. Yasutake, R. Findlay, I. A. Franchi,
J. A. Malley, K. A. McCain, N. Matsuda, K. D. McKeegan, K. Hirahara, A. Takeuchi,
S. Sekimoto, I. Sakurai, I. Okada, Y. Karouji, T. Yada, M. Abe, T. Usui, S. Watanabe and
Y. Tsuda

Study of Pygmy Dipole Resonance using Linearly Polarized Photon
Beam [1U]

T. Shizuma, M. Omer, T. Hayakawa, K. Ali, H. Zen, H. Ohgaki, S. Miyamoto, K. Sugita
and Y. Taira

X-ray Absorption Spectra of Lipid Bilayer Membranes in Aqueous
Solutions [3U]
R. Tero, Yu Kinjo and M. Nagasaka

Evaluation of Exposure-Effects on Biomolecules for the Molecular
Mapping of Biological Specimens Using STXM [4U]
A. Ito, K. Shinohara, A. Matsuura, S. Toné, M. Torigata, K. Tohya, H. Yuzawa and
T. Ohigashi

Physicochemically Characterization of Dust/Salt Mixtures
Originating from the Source of East Asian Dust Storms [4U]
J. Li, W. Liu, L. Li, T. Ohigashi, M. Hallquist, S. Wang and X. Kong

00
00
149
00
00
150
00
151
00
152
00
00
153
00

ix

00

Development of Multilayer-coated Mirrors for the Next Generationof the Inner Magnetospheric Imaging [5B]
K. Inoue, A. Tomioka, J. Yang, H. Lin, K. Yoshioka and I. Yoshikawa

Performance Evaluation of an Optical Filter Aiming for Observationof Atmosphere of Comets [5B]
Y. Sasaki, Y. Suzuki, K. Yoshioka, M. Taguchi, M. Kuwabara, H. Akadama, T. Kosugi,
H. Lin and J. Yang

Performance Evaluation of UV Absorption Filter Onboard Spacecraft[5B]
Y. Suzuki, M. Kuwabara, M. Taguchi, K. Yoshioka, T. Katsumata, M.Tateyama,
K. Goda, A. Yamazaki, K. Inoue and A. Tomioka

154

155

156

The Effect of Space Weathering on The PAH Wavelength ofInterstellar Dust Organic Matter [7B]

157

A study on Space weathering of Carbonaceous Meteorites by Farultraviolet Spectroscopy [7B]158

J. Yang, H. Lin, K. Inoue, A. Tomioka, K. Yoshioka and I. Yoshikawa

H. Akadama, Y. Suzuki, J. Yang and K. Yoshioka

IV. List of Publications
IV. List of Publications
V. Workshops
V. Workshops

159
159

UVSOR Symposium 2021
The 4th workshop on prospects and construction plan of the next
generation synchrotron radiation facility
2021 IMS Open House Event

x

165
165
00
00
167
00
00
170
00
00
172
00
00
00
00

Ⅰ

Organizationand Staf f List

Ⅰ．Organization and Staff List

UVSOR Synchrotron Facility Organization

IMS

ⅠMar. 2022

KAWAI, Maki (Director General)

UVSOR Steering Committee
Department

Photo-Molecular Science III

Technical and Engineering
Departments

Electronic Structure
YOKOYAMA, Toshihiko
KIMURA, Shin-ichi (Cross Appt. Osaka Univ.)

Research Center

Visiting Professor:
SHIMADA, Kenya (Hiroshima Univ.)

UVSOR

KERA, Satoshi
TAKAYA, Hikaru (Cross Appt. Kyoto Univ.)

KERA, Satoshi (Director)

Advanced Accelerator Research:
KATOH, Masahiro (Cross Appt. Hiroshima Univ.)
Beam Physics and Diagnostics Research:
MATSUI, Fumihiko and TAIRA, Yoshitaka
Advanced Solid State Physics:
TANAKA, Kiyohisa
Advanced Photochemistry:UVSOR Users Association

3

Ⅰ．Organization and Staff List

Ⅰ

Staff List

Mar. 2022

UVSOR Staff
Director
KERA, Satoshi

Professor

kera@ims.ac.jp

Division of Advanced Accelerator Research
KATOH, Masahiro

Project Professor
mkatoh@ims.ac.jp(Cross Appt. Hiroshima Univ.)

FUJIMOTO, Masaki

Assistant Professor

mfmoto@ims.ac.jp

SALEHI, Elham

Project Research Staff

elham@ims.ac.jp

Division of Beam Physics and Diagnostics Research
MATSUI, Fumihiko

Professor

matui@ims.ac.jp

TAIRA, Yoshitaka

Associate Professor

yostaira@ims.ac.jp

OHIGASHI, Takuji

Associate Professor(Cross Appt. KEK)

ohigashi@ims.ac.jp

SUGITA, Kento

Assistant Professor

ksugita@ims.ac.jp

MATSUDA, Hiroyuki

Project Research Staff

hmatsuda@ims.ac.jp

Division of Advanced Solid State Physics
TANAKA, Kiyohisa

Associate Professor

k-tanaka@ims.ac.jp

Division of Advanced Photochemistry
IWAYAMA, Hiroshi

Assistant Professor

iwayama@ims.ac.jp

Technical Staff
HAYASHI, Kenji

Engineer（Unit Leader）		

NAKAMURA, Eiken

Chief Engineer		

MAKITA, Seiji

Engineer		

YAMAZAKI, Jun-ichiro

Chief Technician		

SAKAI, Masahiro

Chief Technician		

YANO, Takayuki

Chief Technician		

OKANO, Yasuaki

Chief Technician		TESHIMA, Fumitsuna

Chief Technician		

KONDO, Naonori

Chief Technician		

YUZAWA, Hayato

Technician		

OTA, Hiroshi

Technician		

HORIGOME, Toshio

Technical Fellow		

4(until Mar. 2022)

Ⅰ．Organization and Staff List

MIZUKAWA, Tetsunori

Technical Fellow		

MINAKUCHI, Aki

Technical Fellow		

Ⅰ

Secretary			
ISHIHARA, Mayumi			
KAMO, Kyoko			

Departments in IMS(* Group Leader）

Division of Photo-Molecular Science III			
KERA, Satoshi *Professor		

TAKAYA, Hikaru

Associate Professor (Cross Appt. Kyoto Univ.)

NAGASAKA, Masanori

Assistant Professor		

FUKUTANI, Keisuke

Assistant Professor		

Division of Photo-Molecular Science Ⅳ			SHIMADA, Kenya

Visiting Professor (Hiroshima Univ.)(until Mar. 2022)

Division of Electronic Structure			
YOKOYAMA, Toshihiko *Professor		

KIMURA, Shin-ichi

Professor (Cross Appt. Osaka Univ.)

KOITAYA, Takanori

Assistant Professor		

YAMAMOTO, Kohei

Assistant Professor		

Graduate Students
MIYATA, Takeshi

Chubu Univ.		

(until Mar. 2022)

KANAZAWA, Shingo

Chiba Univ.		

(until Mar. 2022)

GOTO, Keita

Nagoya Univ.		

(since Nov. 2021)

TABE, Keigo

Nagoya Univ.		

(since Nov. 2021)

SUGIMOTO, Takafumi

Nagoya Univ.		

(since Nov. 2021)

HOSHINA, Takumi

Nagoya Univ.		

(since Nov. 2021)

YAMAUCHI, Saki

Nagoya Univ.		

(since Jan. 2022)

UVSOR Steering Committee
KERA, Satoshi *UVSOR, IMS		MATSUI, Fumihiko

UVSOR, IMS		KATOH, Masahiro

UVSOR, IMS		TANAKA, Kiyohisa

UVSOR, IMS		TAIRA, Yoshitaka

UVSOR, IMS		SHIMADA, Kenya

UVSOR, IMS (Hiroshima Univ.)

5(* Chair)(until Mar. 2022)

Ⅰ．Organization and Staff ListⅠ

OKUDA, Taichi

Hiroshima Univ.		

(until Mar. 2022)

KUMIGASHIRA, Hiroshi

Tohoku Univ.		

(until Mar. 2022)

HATSUI, Takaki

RIKEN		

(until Mar. 2022)

KANEMITSU, Yoshihiko

Kyoto Univ,		

KIMURA, Shin-ichi

Osaka Univ.		

HARADA, Yoshihisa

Univ. of Tokyo		

FUKUSHIMA, Takanori

Tokyo Institute of Technology		

KAWAI, Maki

IMS, Director General		(until Mar. 2022)

AKIYAMA, Shuji

IMS		

(until Mar. 2022)

KUSAMOTO, Tetsuro

IMS		

(until Mar. 2022)

YAMAMOTO, Hiroshi

IMS		(until Mar. 2022)

YOKOYAMA, Toshihiko

IMS		SHIGEMASA, Eiji

IMS		

HAYASHI, Kenji

IMS		NAKAMURA, Toshikazu

IMS		

UVSOR Users Association(* Chair)

KIMURA, Shin-ichi *Osaka Univ.		

KITAURA, Mamoru

Yamagata Univ.

OKABAYASHI, Jun

Univ. of Tokyo		(until Mar. 2022)

YAMANE, Hiroyuki

PhoSIC		(until Mar. 2022)

HIKOSAKA, Yasumasa

Toyama Univ.

6(until Mar. 2022)

Ⅱ

Current Status ofLight Sources andBeamlinesⅡ . Current Status of Light Sources and Beamlines

Light Source in 2021
Yoshitaka TairaUVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, JapanⅡIn FY2021, UVSOR-III was scheduled to operate
for 36 weeks from end of May 2021 to March 2022 forusers. However, the user operation time was cut by two
weeks due to a vacuum leak incident and its restoration
work. Finally, the 300 mA multi-bunch top-up mode
was operated for 32 weeks and the 35 mA single-bunch
top-up mode for 2 weeks. Monthly statistics ofoperation time and integrated beam current are shownin Figure 1.
From April 1 to May 7 was a shutdown period,
during which periodic inspections and replacement of
sextupole coils were conducted. The details of thereplacement of sextupole coils are described in last
year's activity report [1]. The replacement of the
sextupole coils was conducted over a multi-year period,
and all replacements were completed during thisperiod. The two weeks following the shutdown wereallocated to the adjustment of the accelerator andbeamlines.
The vacuum leak accident over the entire circumferenceof the storage ring was occurred in July 2021 and wascaused by water leaking from the cooling water pipe ofthe four-quadrant slit used to cut out the synchrotron
radiation, which is located between the manual valve
and the fast-acting valve immediately after the bending
magnet. It took a total of five weeks for baking,photobaking, and adjustment of the accelerator andbeamlines before user operation resumed.
Minor machine problems including the failure of thebeam position monitor module due to an instantaneousvoltage drop and the failure of the RF-frequency signal
oscillator, both of which were addressed by replacing
them with alternatives or repairing them.
The weekly operation schedule is as follows. Mondays
are assigned to machine studies from 9:00 AM to 9:00
PM. User operation is assigned Tuesday through Friday,with Tuesday and Wednesday operating from 9:00 AM
to 9:00 PM, and Thursday from 9:00 AM to 9:00 PM on
Friday for 36 continuous hours. Thus, the user's beamtime per week is 60 hours.
We started a design study for the future plan of
UVSOR-IV. As a first step, we have analyzed thepresent magnetic lattice, seeking a possibility to reduce
the emittance more [2]. Although, we did not find asolution to drastically reduce emittance, we have founda few interesting solutions that achieved lower
emittance than the current situation. As the second step,
we have started designing a totally new storage ring,which is close to the diffraction limit in the VUV range.
The light source development and utilization
beamline BL1U, constructed under the support ofQuantum Beam Technology Program by MEXT/JST,

continue to develop new light source technologies andtheir applications such as free electron laser, coherent
harmonic generation, coherent synchrotron radiation,
coherent control [3], laser Compton scattered gamma
rays [4], and optical vortices.
In particular, in April 2021, a new vacuum duct for
laser injection was installed in the storage ring, shownin Figure 2. To solve the space constraint, a manualvalve and injection windows were integrated. By using
this injection windows, the gamma ray intensity wasincreased by a factor of 10 or more.

Ⅱ

Current Status ofLight Sources andBeamlines

Fig. 1. Monthly statistics in FY2021.

Fig. 2. Laser injection vacuum duct installed in April
2021.
[1] M. Katoh, UVSOR Activity Report (2021).
[2] E. Salehi and M. Katoh, Proceedings of IPAC2021(2021) 3970.
[3] T. Kaneyasu et al., Phys. Rev. Lett. 126 (2021)
113202.
[4] K. Ali et al., Appl. Sci. 11 (2021) 3415.

9

Ⅱ . Current Status of Light Sources and Beamlines

Ⅱ

10

2

Ⅱ . Current Status of Light Sources and Beamlines

Ⅱ

3
11

Ⅱ . Current Status of Light Sources and Beamlines

Beamlines in 2021
Fumihiko Matsui
UVSOR synchrotron Facility, Institute for Molecular ScienceⅡ
BL4U, which is equipped with a scanningtransmission soft X-ray microscope (STXM), is
actively used not only by academic users but also
by many industrial users. In FY2020, it became
possible to image the lithium K-edge with aspatial resolution of 72 nm. Final adjustments forthe airtight sample transport system and thesample transport container were carried out forthe organic substance analysis of the Hayabusa2
returned samples for the summer of FY2021.
 In BL5U, high energy resolution angle-resolved
photoemission spectroscopy (ARPES) is available.
Users can now use so-called “deflector mapping”
for all kinetic energies and lens modes by using
the latest version of ARPES analyzer. An alkalimetal deposition system has been installed.
Potassium for example can be deposited while thesample is still mounted on the manipulator at low
temperatures. As part of the development of spinresolved ARPES, a two-dimensional image of thespin-resolved spectrum of the Rashba splitting of
Au(111) surface has been successfully obtained.
 At BL6U, one of the In-house beamlines,
photoelectron momentum microscope (PMM),
which is a new-concept multi-modal electronic
structure analysis system with high resolution inreal space and momentum space, has been
installed and is in operation. Experiments such as
valence band photoelectron spectroscopy on the
micrometer scale and resonance photoelectron
diffraction by soft X-ray excitation are performed.
In FY2021, valence band study on graphenes,
high-temperature superconductors, dichalcogenides,
and organic molecular adsorbates were conductedin collaboration with several groups. In FY2022,
we plan to further expand PMM's capabilities byintroducing an additional 2D spin filter.
 At BL7U, high-energy resolution ARPES isavailable with extremely low energy of photons (6eV~) using the low-temperature 6-axis manipulator
with a sample temperature 4.5-350 K. In FY2022,
the deflector-type detector for the hemisphericalanalyzer was installed to realize an effective 2D
measurement with the automated manipulator
control. Users can perform the measurement of thebulk sensitive electronic structure of solids and thehigh-throughput measurement for molecularmaterials using high-photoionization cross-section
using low-excitation photon energy.
Those wishing to use the open and in-housebeamlines are recommended to contact the appropriate
beamline contact persons (see next page). Applications
can be submitted at NOUS (https:// nous.nins.jp/user/
signin). All users are required to refer to the beamline

UVSOR is one of the highest-brilliance light sourcesin the extreme-ultraviolet region among the synchrotron
radiation facilities with electron energies of less than 1
GeV. The low natural emittance of the UVSOR-III
storage ring, 17.5 nm-rad, was accomplished after the
successful completion of the storage ring upgrade
project (the UVSOR-III project) in 2012. Eight bending
magnets and six insertion devices are available assynchrotron light sources at UVSOR. There are a totalof fourteen operational beamlines. Twelve of them are
the so-called “Public beamlines”, which are open toscientists from universities and research institutes
belonging to the government, public organizations,private enterprises and also those from foreign countries.
The beamline BL6U is the “In-house beamlines”, andare dedicated to the use of research groups within
Institute for Molecular Science (IMS). The beamline
BL1U is a partially "Public" and partially "In-house"beamline. There is one tender X-ray (TX) stationequipped with a double-crystal monochromator, seven
extreme ultraviolet (EUV) and soft X-ray (SX) stations
with grazing incidence monochromators, three vacuum
ultraviolet (VUV) stations with normal incidence
monochromators, two infrared (IR) stations equippedwith Fourier Transform interferometers, and one direct
radiation station located after two tandem undulators, as
shown in the appended table (next page) for all available
beamlines at UVSOR in 2021. The details of the updates
for undulator beamlines are the followings.
 In BL1U, the development of a new light source
and the utilization of gamma-rays are being
carried out. Users are provided with gamma-ray
induced positron annihilation spectroscopy that
can analyze nanometer-order defects in bulk
materials. To increase the counting rate ofannihilation gamma rays, an array detector witheight BaF2 scintillators was developed. The
measurement can be completed in a few hours formetal samples.
 In BL3U, the ultrathin-liquid cell for low-energy
XAS has been developed. The studies of local
structures of several aqueous solutions andvarious chemical processes in solution such as
catalytic and electrochemical reactions, andlaminar flows in microfluidics by using operando
XAS in C, N, and O K-edges were demonstrated.
Moreover, we have established an argon gas
window that is effective from 60 to 240 eV withthe removal of high-order X-rays, which willdevelop chemical research since it includes Kedges of Li and B and L-edges of Si, P, S, and Cl.
Resonant soft X-ray scattering for soft materials
is also applicable.



4
12

Ⅱ . Current Status of Light Sources and Beamlines

manuals and the UVSOR guidebook, on the occasionof conducting the actual experimental procedures. For

updated information on UVSOR, please see http://
www. uvsor.ims.ac.jp.

Ⅱ

5
13

Ⅱ . Current Status of Light Sources and Beamlines

Beamlines at UVSOR
Ⅱ

Beamline

Monochromator /Spectrometer

BL1U

Free electron laser

BL1B

Martin-Puplett FT-FIR

BL2A

Double crystal

BL2B

18-m spherical grating(Dragon)

BL3U

Varied-line-spacing
plane grating(Monk-Gillieson)

BL3B

2.5-m off-plane Eagle
Varied-line-spacing
plane grating(Monk-Gillieson)
Varied-line-spacing
plane grating(Monk-Gillieson)

BL4U
BL4B
BL5U

Spherical grating(SGM-TRAIN†)

BL5B

Plane grating

BL6U*

Variable-included-angle
varied-line-spacing
plane grating

BL6B

Michelson FT-IR

BL7U

10-m normal incidence(modified Wadsworth)BL7B

3-m normal incidence

Energy Range

Targets

585 – 4 keV
23 – 205 eV
40 – 800 eV
1.7 – 31 eV
50 – 770 eV
25 eV – 1 keV
20 – 200 eV
6 – 600 eV
40 – 500 eV
4 meV – 2.5 eV
6 – 40 eV
1.2 – 25 eV

Yellow columns represent undulator beamlines.
In-house beamline.

*

6
14

Contact(Irradiation)

Y. Taira

Solid

Reflection
Absorption

K. Tanaka

Solid

Reflection
Absorption

F. Matsui

Solid

Photoemission

S. KeraGas
LiquidSolid

Absorption
Photoemission
Photon-emission
Reflection
Absorption
Photon-emission

1.6 – 13.9 eV
0.5 – 30 meVTechniquesSolidyostaira@ims.ac.jp

k-tanaka@ims.ac.jp

matui@ims.ac.jp

kera@ims.ac.jp

H. Iwayama

iwayama@ims.ac.jp

F. Matsui

matui@ims.ac.jp

Gas
LiquidSolid

Absorption(Microscopy)

T. Ohigashi

Gas
Solid

Photoionization
Photodissociation
Photoemission

H. Iwayama

Solid

Photoemission

K. Tanaka

Solid

Calibration
Absorption

K. Tanaka

Gas
Solid
Solid

Photoionization
Photodissociation
Photoemission
Reflection
Absorption
IR microscopeohigashi@ims.ac.jp

iwayama@ims.ac.jp

k-tanaka@ims.ac.jp

k-tanaka@ims.ac.jp

F. Matsui

matui@ims.ac.jp

K. Tanaka

k-tanaka@ims.ac.jp

Solid

Photoemission

K. Tanaka

Solid

Reflection
Absorption
Photon-emission

F. Matsui

k-tanaka@ims.ac.jp

matui@ims.ac.jp

BL1U

Light Source Development Station
Ⅱ▼Description
BL1U is dedicated for developments and applications of novel light sources. This beamline is equipped with adedicated tandem undulator for variable polarization with a buncher section, which can be used for free electron
laser in the range from visible to deep UV, VUV coherent harmonic generation (CHG), and generation of
spatiotemporal structured light such as an optical vortex beam, a vector beam and double-pulse wave packets. It
is also equipped with a femto-second laser system synchronized with the accelerator, which is used for thegeneration of CHG, laser Compton scattered gamma-rays, and coherent THz radiation. Nowadays, material
analysis by positron annihilation spectroscopy using laser Compton scattered gamma rays is actively used.

Fig. 1. Configuration of the free electron laser

VerticalCircular

Horizontal

Fig. 2. Brilliance of BL1U Apple-II Undulator

Fig. 3. Accelerator synchronized Laser System▼Technical Data of FEL▼Technical Data of Ti:Sa Laser

Wave Length

199-800 nm

Wave Length

800 nmSpectral Band Width~10

Pulse Length

130 fsec

Polarization

Circular/Linear

Oscillator

90.1 MHz

Pulse Rate

11.26 MHz

Pulse Energy

2.5 mJ

10 mJ

50 mJ

Max. Ave. Power~1 W

Repetition Rate

1 kHz

1 kHz

10 Hz

-4

7
15

BL1B

Terahertz Spectroscopy Using Coherent Synchrotron Radiation
Ⅱ▼Description
Coherent synchrotron radiation (CSR) is a powerful light source in the terahertz (THz) region. This beamline
has been constructed for basic studies on the properties of THz-CSR. However, it can be also used formeasurements of reflectivity and transmission spectra of solids using conventional synchrotron radiation.
The emitted THz light is collected by a three-dimensional magic mirror (3D-MM, M0) of the same type as thosealready successfully installed at BL43IR in SPring-8 and BL6B in UVSOR-II. The 3D-MM was installed inbending-magnet chamber #1 and is controlled by a 5-axis pulse motor stage (x, z translation; θx, θy, θz rotation).
The acceptance angle was set at 17.5-34 degrees (total 288 mrad) in the horizontal direction. The vertical angle
was set at ±40 mrad to collect the widely expanded THz-CSR.
The beamline is equipped with a Martin-Puplett type interferometer (JASCO FARIS-1) to cover the THz spectral
region from 4 to 240 cm-1 (hν = 500 μeV-30 meV). There is a reflection/absorption spectroscopy (RAS) endstation for large samples (∼ several mm). At the RAS end-station, a liquid-helium-flow type cryostat with aminimum temperature of 4 K is installed.

Fig. 1. Schematic top view of the beam extraction part of
the THz-CSR beamline, BL1B. The three-dimensional
magic mirror (3D-MM, M0) and a plane mirror (M1) arelocated in the bending-magnet chamber. A parabolic
mirror (M2) is installed to form a parallel beam. The
straight section (BL1U) is used for coherent harmonic
generation (CHG) in the VUV region.

Fig. 2. Obtained intensity spectra with the
combination of a light source (UVSOR),
interferometer (FARIS-1), and detectors (Sibolometer and InSb hot-electron bolometer).

▼Technical Data
Interferometer

Martin-Puplett (JASCO FARIS-1)

Wavenumber range(Energy range)

4-240 cm-1
(500 μeV-30 meV)

Resolution in cm-1

0.25 cm-1

Experiments

Reflection/transmission spectroscopy

Miscellaneous

Users can use their experimental system in this beamline.

8

16

BL2A

Soft X-Ray Beamline for Photoabsorption Spectroscopy
Ⅱ▼Description
BL2A is a soft X-ray beamline for photoabsorption spectroscopy. The beamline is equipped with a pre-focusing
mirror and a double-crystal monochromator [1]. The monochromator serves soft X-rays in the energy region from
585 to 4000 eV using several types of single crystals, such as beryl, KTP (KTiOPO4), and InSb. The throughput
spectra measured using a Si photodiode (AXUV-100, IRD Inc.) are shown in Fig. 1. The typical energy resolution(E / ΔE) of the monochromator is approximately 1500 for beryl and InSb.
There is a small vacuum chamber equipped with an electron multiplier (EM) detector. Photoabsorption spectra
for powdery samples are usually measured in total electron yield mode, with the use of the EM detector. In addition,a hemispherical electron analyzer for photoelectron spectroscopy is equipped.
Recently, a new omnidirectional photoelectron acceptance lens (OPAL) has been developed aiming to realize
2π-steradian photoelectron spectroscopy and photoelectron holography [2]. By combining OPAL and the existing
hemispherical electron analyzer, a photoelectron spectrometer with high energy resolution can be realized, and afull range (±90°) 1D angular distribution can be measured at once. This upgrade is currently in the commissioning
phase.
[1] Hiraya et al., Rev. Sci. Instrum. 63 (1992) 1264.
[2] H. Matsuda and F. Matsui, Jpn. J. Appl. Phys. 59 (2020) 046503.

Fig. 1. Throughput spectra of the double-crystal monochromator at BL2A.

▼Technical Data

Monochromator
Monochromator crystals:(2d value, energy range)
Resolution
Experiments

Double crystal monochromatorberyl (15.965 Å, 826–2271 eV), KTP (10.95 Å, 1205–3310 eV),InSb (7.481 Å, 1764–4000 eV), Ge (6.532 Å, 2094–4000 eV)
E/ΔE = 1500 for beryl and InSb
Photoabsorption spectroscopy (total electron yield using EM and partial
fluorescence yield using SDD)

9

17

BL2B

Photoelectron spectroscopy of molecular solids
Ⅱ▼Description
This beamline previously dedicated for experiments in the field of gas phase photoionization and reaction
dynamics. Then, the beamline has been reconstructed for photoelectron spectroscopy of molecular solids with a
new end station, and experiments can be performed from May 2014. The monochromator is a spherical grating
Dragon type with 18-m focal length. High throughput (1 × 1010 photons s-1) and high resolution (E/ΔE = 2000 8000) are achieved simultaneously under the condition of the ring current of 100 mA [1]. The optical system
consists of two pre-focusing mirrors, an entrance slit, three spherical gratings (G1 - G3), two folding mirrors, amovable exit slit, and a refocusing mirror [2]. The monochromator is designed to cover the energy range of 23–
205 eV with the three gratings: G1 (2400 lines mm-1, R = 18 m) at 80–205 eV; G2 (1200 lines mm-1, R = 18 m) at
40–100 eV; G3 (2400 lines mm-1, R = 9.25 m) at 23–50 eV. The percentage of the second-order light contamination
at hν = 45.6 eV is 23 % for G2 or 7 % for G3.
A UHV chamber is placed downstream of the refocusing mirror chamber and equipped silicon photodiode,sapphire plate Au mesh and filters for absolute photon flux measurement, monitor the photon-beam position,
relative photon flux measurements and attenuate higher order light, respectively.
The new end station consists of a main chamber with a hemispherical analyzer (SCIENTA R3000) and a liquidHe-cooled cryostat (temperature range of 15-400 K) with 5-axis stage, a sample preparation chamber with a fastentry load-lock chamber and a cleaning chamber with LEED, ion gun for sputtering and IR heating unit.
[1] M. Ono, H. Yoshida, H. Hattori and K. Mitsuke, Nucl. Instrum. Meth. Phys. Res. A 467-468 (2001) 577.
[2] H. Yoshida and K. Mitsuke, J. Synchrotron Radiation 5 (1998) 774.

Fig. 2. End station of BL2B for photoelectron
spectroscopy of molecular solids.

Fig. 1. Throughput from Dragon monochromator.

▼Technical Data
Monochromator

18 m spherical grating Dragon-type

Wavelength Range

23-205 eVResolution

2000–8000 depending on the gratings

Experiments

Angle-resolved ultraviolet photoelectron spectroscopy

10
18

BL3U

Varied-Line-Spacing Plane Grating Monochromatorfor Molecular Soft X-Ray Spectroscopy▼Description
The beamline BL3U is equipped with an in-vacuum undulator composed of 50 periods of 3.8 cm period length.
The emitted photons are monochromatized by the varied-line-spacing plane grating monochromator (VLS-PGM)
designed for various spectroscopic investigations in the soft X-ray range. Three holographically ruled laminar
profile plane gratings are designed to cover the photon energy range from 40 to 800 eV. The beamline has liquidcells for soft X-ray absorption spectroscopy (XAS) in transmission mode as shown in Fig. 1. The liquid cell is in
the atmospheric helium condition, which is separated by a 100 nm thick Si3N4 membrane with the window size of
0.2 × 0.2 mm2 from the beamline in an ultrahigh vacuum condition. The thin liquid layer is assembled by using
two 100 nm thick Si3N4 membranes. The thickness of the liquid layer is controllable from 20 to 2000 nm byadjusting the helium pressures around the liquid cell in order to transmit soft X-rays. Liquid samples areexchangeable in situ by using a tubing pump. The liquid cell has two types of windows: one is the liquid part toobtain the soft X-ray transmission of liquid (I), and the other is the blank part to obtain the transmission withoutliquid (I0). We can obtain the reliable XAS spectra based on the Lambert-Beer law ln(I0/I). Since the liquid cell isin the atmospheric condition, we can measure XAS of liquid samples in the real environment. Operando XAS
observation of several chemical reactions such as catalytic, electrochemical reactions are also possible by using
our liquid cells developed for these purposes.

Fig. 1. (a) Schematics of a liquid cell for XAS in transmission mode settled in BL3U. The blowup shows a thinliquid layer assembled by two Si3N4 membranes with the thickness of 100 nm. (b) Flux at the sample position
with the resolving power of λ/Δλ=104.

▼Technical Data
Monochromator
Energy Range
Resolution
Experiments

Varied-line-spacing plane grating monochromator
40-800 eV
E / ΔE > 10 000
Soft X-ray absorption spectroscopy of liquid in transmission mode

11
19

Ⅱ

BL3B (HOTRLU)Ⅱ

VIS-VUV Photoluminescence and Reflection/Absorption
Spectroscopy▼Description
BL3B has been constructed to study photoluminescence (PL) in the visible (VIS) to vacuum ultraviolet (VUV)
region. This beamline consists of a 2.5 m off-plane Eagle type normal-incidence monochromator, which covers
the VUV, UV, and VIS regions, i.e., the energy (wavelength) region of 1.7-31 eV (40-730 nm), with three sphericalgratings having constant grooving densities of 1200, 600, and 300 l/mm optimized at the photon energies of ~20,
~16, and ~6 eV, respectively. The schematic side view and top view layouts are shown in Figs. 1(a) and 1(b),respectively. The FWHM of the beam spot at the sample position is 0.25 mm (V) × 0.75 mm (H). Low energy passfilters (LiF, quartz, WG32, OG53) can be inserted automatically to maintain the optical purity in the G3 (300 l/mm)
grating region (1.7~11.8 eV). Figure 2 shows the throughput spectra (photon numbers at a beam current of 300mA) for each grating with entrance and exit slit openings of 0.1 mm (resolving power E / ΔE of ~2000 (G3, ~6.8eV)). Since both slits can be opened up to 0.5 mm, a monochromatized photon flux of 1010 photons/s or higher isavailable for PL measurements in the whole energy region.
The end station is equipped with a liquid-helium-flow type cryostat for sample cooling and two detectors; oneof which is a photomultiplier with sodium salicylate and the other a Si photodiode for reflection/absorption
measurement. For the PL measurements in the wide energy region from VIS to VUV, two PL monochromators,
comprising not only a conventional VIS monochromator but also a VUV monochromator with a CCD detector,
are installed at the end station.

Fig. 1. Schematic layout of the BL3B (a) side view and(b) top view.

Fig. 2. Throughput spectra for each grating(G1:1200 l/mm, G2:600 l/mm and G3:300l/mm) with S1 = S2 = 0.1 mm.

▼Technical Data
Monochromator-2.5 m normal-incidence monochromator

Energy range

1.7-31 eV (40~730 nm)

Resolution (Δhν/ hν)≥ 12000 (at ~ 6.9 eV, 0.02 mm slits, G1 (1200 l/mm)

Experiments

Photoluminescence, reflection, and absorption spectroscopy, mainly for solids

12
20

BL4U

Scanning Transmission X-ray Microscopy in the Soft X-ray Region
Ⅱ▼Description
In the soft x-ray region, there are several absorption edges of light elements and transition metals. The near edge
X-ray absorption fine structure (NEXAFS) brings detailed information about the chemical state of target elements.
A scanning transmission X-ray microscope (STXM) in the soft X-ray region is a kind of extended technique of the
NEXAFS with high spatial resolution. The STXM has a capability of several additional options, for example, insitu observations, 3-dimensional observation by computed tomography and ptychography, by utilizing thecharacteristics of the X-rays. The STXM can be applied to several sciences, such as polymer science, materialscience, cell biology, environmental science, and so on.
This beamline equips an in-vacuum undulator, a varied-line-spacing plane grating monochromator and a fixed exit
slit. The soft X-ray energy range from 50 to 770 eV with the resolving power (E/ΔE) of 6,000 is available. The aperturesize of the fixed exit slit determines not only the resolving power but also the size of a microprobe. A Fresnel zone plateis used as a focusing optical device through an order select aperture and its focal spot size of ~30 nm is available atminimum. An image is acquired by detecting intensities of the transmitted X-rays by a photomultiplier tube with
scintillator with scanning a sample 2-dimensionally. By changing the energy of the incident beam, each 2-dimensional
NEXAFS image is stacked. A main chamber of STXM is separated from the beamline optics by a silicon nitride
membrane of 50-nm thickness; therefore, sample folders can be handled in vacuum or in helium.

Slit

PinholeM0 mirror

M1 mirror andGrating

M2 mirror

Fixed exit slit

Fig. 1. Schematic image of BL4U
X-raysFresnel zone plate

Order Sorting
Aperture
SampleCentralstopper

Photo multiplier tube
with scintillator P-43

Fig. 2. Schematic image of STXM

Fig. 3. Photon flux at the sample▼Technical Data
Energy range (E)50 -770 eVResolving power (E/ΔE)~6,000

Photon flux on a sample (photons/s)~2×107 @400 eV

Focusing optical element

Fresnel zone plate

Spatial resolution~30 nmExperiments

2-dimensional absorption spectroscopy
standard sample folder in vacuum or in helium,
specially designed sample cell in ambient condition

Measurement environment

13

21

STXM

BL4B

▼Description
The beamline BL4B equipped with a varied-line-spacing plane grating monochromator (VLS-PGM) wasconstructed for various spectroscopic investigations in a gas phase and/or on solids in the soft X-ray range. Threeholographically ruled laminar profile plane gratings with SiO2 substrates are designed to cover the photon energy
range from 25 to 800 eV. The gratings with groove densities of 100, 267, and 800 l/mm cover the spectral rangesof 25–100, 60–300, and 200-1000 eV, respectively, and are interchangeable without breaking the vacuum. Figure
1 shows the absolute photon flux for each grating measured using a Si photodiode (IRD Inc.), with the entranceand exit-slit openings set at 50 and 50 μm, respectively. The maximum resolving power (E/ΔE) achieved foreach grating exceeds 5000.
There is no fixed endstation on this beamline. A small vacuum chamber equipped with an electron multiplier(EM) detector is available. Soft X-ray absorption spectra of solid samples are usually measured by means of thetotal electron yield method using EM, and the partial fluorescence yield method using a silicon drift detector (SDD).

1E12

G3
Intensity (photons/s)

Ⅱ

Varied-Line-Spacing Plane Grating Monochromatorfor Molecular Soft X-Ray Spectroscopy

1E11

Slit: 50μm-50μm

G2

1E10

G1
1E9

1E8
0

200

400

600

800

1000

1200

Photon Energy (eV)Fig. 1. Throughput from the VLS-PGM monochromatoron BL4B.

Fig. 2. Photo of BL4B.

▼Technical Data
Monochromator

Varied-line-spacing Plane Grating Monochromator

Energy range

25-1000 eVResolution

E / ΔE > 5000 (at maximum)

Experiments

Soft X-ray spectroscopy (mainly, photoabsorption spectroscopy for solid targets
by means of total electron yield method using EM and partial fluorescence yield
method using SDD)

14
22

BL5U

Photoemission Spectroscopy of Solids and Surfaces
Ⅱ▼Description
Since the monochromator of BL5U was an old-style spherical grating type SGMTRAIN constructed in 1990s
and the throughput intensity and energy resolution were poor, the whole beamline has been replaced to state-ofthe-art monochromator and end station. The new beamline has been opened to users from FY2016 as high-energy
resolution ARPES beamline. Samples can be cooled down to 3.8 K with newly developed 5-axis manipulator toperform high energy resolution measurements. Users can also obtain spatial-dependence of the electronic structureof solids using micro-focused beam (~ 50 μm). The new electron lens system makes it possible to obtain ARPES
spectra without moving samples. This beamline will also have new capability to perform high-efficient spinresolved ARPES in the future.

Fig. 1. Picture and photon flux of BL5U.

▼Technical Data (Expected Performance)
Light source

APPLE-II type undulator (λu = 60 mm, N = 38)
vertical/horizontal, right/left circular (depending on hv)

Monochromator

Monk-Gillieson VLS-PGM

Energy Range

20-200 eVResolution

hv/ ΔE > 10,000 for < 10 μm slits

Experiment

ARPES, Space-resolved ARPES, Spin-resolved ARPES

Flux<1012 photons/s for <10 μm slits (at the sample position)

Beam spot size

23 (H) x 40 (V) µm

Main Instruments

Hemispherical photoelectron analyzer with deflector scan (MBS A-1 Lens#4),
Liq-He flow cryostat with 5-axis manipulator (3.8 K-350 K)

15

23

BL5B

Calibration Apparatus for Optical Elements and Detectors
Ⅱ▼Description
BL5B has been constructed to perform calibration measurements for optical elements and detectors. This
beamline is composed of a plane grating monochromator (PGM) and three endstations in tandem. The most
upstream station is used for the calibration measurements of optical elements, the middle one for opticalmeasurements for solids, and the last for photo-stimulated desorption experiments. The experimental chamber at
the most downstream station is sometimes changed to a chamber for photoemission spectroscopy. The calibrationchamber shown in Fig. 2 is equipped with a goniometer for the characterization of optical elements, which has six
degrees of freedom, X-Y translation of a sample, and interchanging of samples and filters. These are driven bypulse motors in vacuum. Because the polarization of synchrotron radiation is essential for such measurements, therotation axis can be made in either the horizontal or vertical direction (s- or p-polarization).

Fig. 1. Throughput spectra for possible combinations ofgratings and mirrors at BL5B measured by a gold mesh.

Fig. 2. A side view of the experimental chamber
for calibration measurements.

▼Technical Data
Monochromator

Plane Grating Monochromator

Energy range

6-600 eV (2-200 nm)

Resolution

E / ΔE ~500

Experiments

Calibration of optical elements, reflection and absorption spectroscopy mainly
for solids

16
24

BL6U

Variable-Included-Angle / Variable-Line-Spacing Plane Grating
Monochromator for Soft X-Ray photoelectron Spectroscopy▼Description
The beamline BL6U equipped with a variable-included-angle Monk-Gillieson mounting monochromator witha varied-line-spacing plane grating was constructed for various spectroscopic investigations requiring highbrilliance soft X-rays on solid surfaces. Through a combination of undulator radiation and sophisticatedmonochromator design (entrance slit-less configuration and variable-included-angle mechanism), using a single
grating, the monochromator can cover the photon energy ranging from 40 to 500 eV, with resolving power ofgreater than 10000 and photon flux of more than 1010 photons/s. Figure 1 shows an example of themonochromator throughput spectra measured using a Si photodiode, with the exit-slit opening set at 30 μm, whichcorresponds to the theoretical resolving power of 10000 at 80 eV.
A new Momentum Microscope experimental station for photoelectron spectroscopy resolved in 3D
momentum space with a microscopic field of view has been built at BL6U (SPECS KREIOS 150 MM). A
momentum resolution of 0.01 Å-1 in kx/ky as well as kz is achieved. A spatial resolution of 50 nm, an energy
resolution of 20 meV at 9 K, and a field of view of 2 μm for ARPES are successfully demonstrated. This
experimental station specializes in characterizing the electronic structure of surface atomic sites, thin films,
molecular adsorbates, and bulk crystals. This method opens the door to direct observation of the Fermi
surface of μm-sized crystals, which was difficult with conventional ARPES-type hemispherical analyzers.

Throughput spectra of the BL6U (Gap=13 mm, Slit=30μm)

Flux(Photons/s/100mA:PD-AXUV100G)

1E13

3rd

1E12

5th

1st

1E11

α+β=168°α+β=170°α+β=172°α+β=174°

1E10
1E9
1E8
1E7

30

100

Photon energy(eV)Fig. 2. Photograph of BL6U end station

Fig. 1. Throughput spectra of the BL6U
monochromator at various included angles.

▼Technical Data
Monochromator

Variable-included-angle Varied-line-spacing Plane Grating Monochromator

Energy range

40-500 eV(practical)

Resolution

E / ΔE > 10000 (at maximum)

Experiments

High-resolution soft X-ray spectroscopy (photoelectron spectroscopy for solid
surfaces)

17
25

Ⅱ

BL6B

Infrared and Terahertz Spectroscopy of Solids
Ⅱ▼Description
Synchrotron radiation (SR) has good performance (high brilliance and high flux) not only in the VUV and soft
X-ray (SX) regions but also in the infrared (IR) and THz regions. BL6B covers the IR and THz regions. The
previous beamline, BL6A1, which was constructed in 1985, was the pioneer in IRSR research. The beamline wasdeactivated at the end of FY2003 and a new IR/THz beamline, BL6B (IR), was constructed in FY2004. The frontend part including bending duct #6 was replaced with a new part having a higher acceptance angle (215 (H) × 80(V) mrad2) using a magic mirror, as shown in Fig. 1.
There are two Michelson type interferometers in this endstation; with first one (Bruker Vertex70v), which covers
a wide spectral region from 30 to 20,000 cm-1 (hν = 4 meV-2.5 eV), reflection/absorption spectroscopy measurementsof large samples (up to several mm) and IR/THz microscopy measurements of tiny samples (up to several tens ofμm) can be performed. For reflection/absorption spectroscopy measurements, a liquid-helium- flow type cryostat
with a minimum temperature of 4 K is installed. The other interferometer (Jasco FT/IR-6100), which covers 350 to
15,000 cm-1 (hν = 45 meV-1.8 eV), has been available for IR microscopy imaging measurements from FY2014. One
can also perform ATR measurements using diamond ATR prism.

Reflection/absorption
end station

Michelson FT-IR(Jasco FT/IR-6100)

IR microscopy imaging(Jasco IRT-7100)

Michelson FT-IR(Jasco FT/IR-6100)

Fig. 2. Obtained intensity spectra with the combinationof a light source (UVSOR), detector (Si bolometer), andinterferometer (Bruker Vertex70v) with different
beamsplitters (6 μm Mylar and KBr) . (Only low energy
side is shown).

Fig. 1. Schematic top view of BL6B.

▼Technical Data
Interferometer

Michelson (Bruker Vertex70v)

Michelson (Jasco FT/IR-6100)

Wavenumber Range(Energy range)

30-20,000 cm(4 meV-2.5 eV)

350-15,000 cm-1
(45 meV-1.8 eV)Resolution in cm-1

0.1 cm-1

0.5 cm-1

Experiments

Reflectivity and transmission
spectroscopy
THz Microspectroscopy

IR microscopy imaging (JASCO IRT-7000)
ATR spectroscopy

-1

18
26

BL7U (SAMRAI)

Angle-Resolved Photoemission of Solids in the VUV Region
Ⅱ▼Description
Beamline 7U, named the Symmetry- And Momentum-Resolved electronic structure Analysis Instrument(SAMRAI) for functional materials, was constructed to provide a photon flux with high energy resolution and highflux mainly for high-resolution angle-resolved photoemission spectroscopy, so-called “ARPES”, of solids [1]. An
APPLE-II-type variable-polarization undulator is installed as the light source. The undulator can produce intense
VUV light with horizontal/vertical linear and right/left circular polarization. The undulator light ismonochromatized by a modified Wadsworth type monochromator with three gratings (10 m radius; 1200, 2400,
and 3600 lines/mm optimized at hv = 10, 20, and 33 eV). The energy resolution of the light (hv/Δhv) is more than
104 with a photon flux of 1011-1012 ph/s or higher on samples in the entire energy region. The beamline has aphotoemission end-station equipped with a 200 mm-radius hemispherical photoelectron analyzer (MB Scientific
AB, A-l analyzer) with a wide-angle electron lens and a liquid-helium-cooled cryostat with 6-axis pulse motor
control. The main function of the beamline is to determine the electronic structure of solids and its temperaturedependence in order to reveal the origin of their physical properties.
[1] S. Kimura, T. Ito, M. Sakai, E. Nakamura, N. Kondo, K. Hayashi, T. Horigome, M. Hosaka, M. Katoh, T. Goto,
T. Ejima and K. Soda, Rev. Sci. Instrum. 81 (2010) 053104.

Fig. 1. SAMRAI beamline [(a), (b)]consisting of an APPLE-II typeundulator (U7), a modified Wadsworth
type monochromator (M0-S), and ahigh-resolution photoemission analyzer
at the focal point. The monochromator
has five major optical components: twoplane mirrors (M0 and M1) with watercooling, one set of three sphericalgratings (G), an exit slit (S), and one
toroidal refocusing mirror (M3). (c)Example of flux intensity versus
photon energy [1]▼Technical Data
Light source

APPLE-II type undulator (λu = 76 mm, N = 36)vertical/horizontal, right/left circular (depending on hv)

Monochromator

10 m normal-incidence monochromator (modified Wadsworth type)

Photon energy range

6 – 40 eV (λ = 30 – 200 nm)

Resolution (hv/Δhv)

E / ΔE > 10000-50000

Photon flux on sample≥ 1011-1012 ph/s (depending on hv)

Beam size on sample

200 (H) × 50 (V) μm2

Experiments

Angle-resolved photoemission of solids(MV Scientific A-1 analyzer, acceptance angle: ± 18 deg)

19
27

BL7B

3 m Normal-Incidence Monochromator for Solid-State Spectroscopy
Ⅱ▼Description
BL7B has been constructed to provide sufficiently high resolution for conventional solid-state spectroscopy,
sufficient intensity for luminescence measurements, wide wavelength coverage for Kramers–Kronig analyses, andminimum deformation to the polarization characteristic of incident synchrotron radiation. This beamline consistsof a 3-m normal incidence monochromator, which covers the vacuum ultraviolet, ultraviolet, visible, and infrared,i.e., the wavelength region of 50–1000 nm, with three gratings (1200, 600, and 300 l/mm). Two interchangeablerefocusing mirrors provide two different focusing positions. For the mirror with the longer focal length, an LiF or
a MgF2 window valve can be installed between the end valve of the beamline and the focusing position. Figure 1
shows the absolute photon intensity for each grating with the entrance and exit slit openings of 0.5 mm. A silicon
photodiode (AXUV-100, IRD Inc.) was utilized to measure the photon intensity and the absolute photon flux was
estimated, taking the quantum efficiency of the photodiode into account.
The cooling system for the pre-focusing mirror has been removed, resulting in longer beam settling times.
Currently, BL7B is opened during single bunch mode, but limited use is possible during multi bunch mode.

Fig. 1. Throughput spectra of BL7B measured using
a silicon photodiode.

Fig. 2. Photo of BL7B.

▼Technical Data
Monochromator

3 m Normal-Incidence Monochromator

Wavelength Range

50-1000 nm (1.2-25 eV)Resolution

E / ΔE = 4000-8000 for 0.01 mm slits

Experiments

Absorption, reflection, and fluorescence spectroscopy, mainly for solids

20
28

UVSOR User 1

UVSOR User 2

Ⅲ-1

Accelerators andInstruments

BL1UⅢ -1. Accelerators and Instruments

BL1U

Improvement of Image Quality of Selective Isotope 3D-CT in UVSOR-BL1U
H. Ohgaki1, K. Ali1, H. Zen1, T. Kii1, T. Hayakawa2, T. Shizuma2, M. Fujimoto3, Y. Taira3and M. Katoh3,4Institute of Advanced Energy, Kyoto University, Kyoto 611-0011, Japan
Tokai Quantum Beam Science Center, National Institutes for Quantum and Radiological Science and Technology,
Ibaraki 319-1106, Japan
3
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
4
Hiroshima University, Higashi-Hiroshima 739-8511, Japan
1

2

Ⅲ -1
Nuclear Resonance Fluorescence (NRF) is a
powerful tool to identify the specific isotope, especiallyin combination with a Laser Compton Backscattering(LCS) gamma-ray beam which provides quasimonochromatic and energy variable gamma-rays. We
have been developed an NRF-CT technique by using
the LCS gamma-ray beam available at the beamline
BL1U in UVSOR and demonstrated a three-dimensional(3D) isotope-selective CT image of the enriched leadisotope distribution of 208Pb in a cylindrical holder (Fig.
1), so far [1]. However, we needed 48 h beam time toobtain a CT image with a 4 mm/pixel in the horizontal
plane and 8 mm/pixel in the vertical plane using the
LCS gamma-ray beam with a beam size of 2 mm and aflux density of 10 photons/s/eV.
To overcome this problem, we proposed a fusion
visualization (FV) technique by combining the NRF-CT
image which provides a rough distribution of targeting
isotope with a gamma-ray CT image which can beobtained by the same measurement system with NRFCT but can provide better pixel resolution with a shortmeasurement time (5 hours) [2]. We measured a 3D
gamma-CT image of the same CT target [1] with the 3D
NRF-CT in BL1U. The obtained 3D gamma-CT image(Fig. 2) has a 1 mm/pixel resolution with an LCS
gamma-ray beam size of 1 mm and a flux density of 0.7
photons/s/eV. The target consists of two enriched leadisotopes (206,208Pb), iron, and aluminum. As shown in
Fig. 2, two enriched lead isotopes can be obtained but
we cannot identify which one is the target isotope 208Pb.
After a few FV methods were applied to construct an
FV image between NRF-CT and gamma-ray CT images,
the post-multiply FV method which can keep thequantitative information of NRF interaction was
selected. Figure 3 shows the 3D isotope-selective fused
CT image. Consequently, we can improve the image
quality of 3D NRF-CT of 208Pb rods embedded in thealuminum cylinder with 206Pb rod as well as iron rods
with keeping quantitative information of NRF
interaction.
[1] K. Ali et al., “Three-Dimensional Nondestructive
Isotope-Selective Tomographic Imaging of 208Pb
Distribution via Nuclear Resonance Fluorescence.”
Appl. Sci. 11 (2021) 3415.
https://doi.org/10.3390/app11083415.

[2] K. Ali, et al., “Fusion Visualization TecFighniqueto Improve a Three-Dimensional Isotope-Selective CT
Image Based on Nuclear Resonance Fluorescencewith a Gamma-CT Image”, Appl. Sci. 11 (2021) 11866.
https://doi.org/10.3390/app112411866.

Fig. 1. 3D NRF-CT image measured in BL1U.

Fig. 2. 3D Gamma-ray CT image measured in BL1U.

Fig. 3. 3D FV NRF-CT image

33 1 Ⅲ01-

BL1U
Ⅲ -1. Accelerators
and Instruments

BL1U

Photon Counting Experiments of Young's Double-Slit Interference Using
Undulator Vortex Radiation

Ⅲ -1

S. Wada1,2, H. Ohta2, A. Mano3, M. Fujimoto4,3 and M. Katoh5,2,4

Graduate School of Advanced Science and Engineering, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
2
Faculty of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
3
Synchrotron Radiation Research Center, Nagoya University, Nagoya 464-8603, Japan
4
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
5
Hiroshima Synchrotron Radiation Center, Hiroshima University, Higashi-Hiroshima 739-0046, Japan

1

Recent theoretical and experimental progresses in thesynchrotron radiation technology reveal that highharmonics emitted from a helical undulator possesses
helical wave-front structure [1,2]. The undulator
beamline BL1U at UVSOR can produce fundamental
and its harmonics of circularly polarized radiation invisible and UV regions. Therefore, leading experiments
using vortex radiation from the undulator have been
conducted [3,4]. Especially, Young’s double-slit
interference experiments demonstrated the characteristic
nature of vortex radiation as a singularity in the middleof the interference pattern arising from helical wavefront structure. This phenomenon is quite interestingfrom the view point whether a single photon
spontaneously emitted from a high-energy electron canalso possess such a characteristic or not. In this study,
we demonstrated Youngs double-slit experiments underphoton-counting condition in order to confirm the above
nature of vortex radiation from a helical undulator [5].
Experiments were performed at UVSOR BL1U
under quite low-current mode (less than 1 mA).
Circularly polarized radiation centered at 355 nm ofsecond harmonics was extracted from a vacuum
beamline to atmosphere via a quart window, passed
through an iris and an interference filter (Alluxa 7057)
in order to extract center part and remove fundamental
710 nm light from the undulator radiation, and thenirradiated onto a double-slit (0.1 mm width and 1 mm
separation). By using as few optics as possible mentioned
above, we could achieve very low simultaneous
detection of two photons, that is single-photon counting
condition in keeping helical wave-front structure. Single
photons after interference were detected by a gated
ICCD camera system (Hamamatsu Photonics, M797101 and ORCA-05G) 1 m far from the double-slits.
After confirming the double-slit interference in thisexperimental setup under multiphoton detection modeusing a normal CCD camera, we could measureinterference pattern even by photon counting detection
as shown in Fig. 1(a). The figure was obtained byintegrating 5000 shots of images with an exposure timeof 200 us, and about 150 photons were randomly
detected in each image. As clearly shown in the figure,
we can find stripes due to interference by the double-slit
and the singularity, that is mismatch of stripes at thedark middle region. The result obviously demonstrates
that the interference patters of circularly polarizedradiation from a helical undulator exhibit characteristics
of optical vortex even under single-photon counting
condition. The nature of vortex radiation from theundulator in the photon-counting condition is also
confirmed by removing the double-slit as shown in Fig.
1(b), indicating the integrated beam profile like donutshaped with the center missing. This is characteristic ofvortex radiation with no light intensity due to a phasesingularity.

Fig. 1. (a) Young's double-slit interference pattern ofvortex radiation measured at BL1U under photoncounting condition. (b) Integrated beam profile
without the double-slit.

[1] S. Sasaki and I. McNulty, Phys. Rev. Lett. 100 (2008)
124801.
[2] J. Bahrdt et al., Phys. Rev. Lett. 111 (2013) 034801.
[3] M. Katoh et al., Sci. Rep. 7 (2017) 6130.
[4] T. Kaneyasu et al., J. Synchrotron Rad. 24 (2017)934.
[5] H. Ohta, B.Sc. Thesis, Hiroshima University (2021).

34 2 Ⅲ01-

Others

Ⅲ -1. Accelerators and Instruments

OthersDevelopment Mass Production Facilities of Nuclear Emulsion Films
I. Usuda, H. Rokujo and M. Nakamura

Graduate School of Science, Nagoya University, Nagoya 464-8602, Japan

Nuclear emulsion is a kind of photographic films
that have sensitivity for ionizing radiation. The films
record tracks of charged particle with high angularresolution.
In Nagoya University, we have developed gel
production machine and developed several types of
emulsion by ourselves. We are planning someexperiments (e.g., gamma ray telescope, neutrino
interaction research, muon radiography) using morethan 500 m2 nuclear emulsion films.
Nuclear emulsion is made by coating emulsion gelon plastic base. Previously, it was difficult to makelarge amount of films because we have coatedemulsion gel by hand.
We have developed roll-to-roll coating machine in
Nagoya University (Fig. 1). For mechanical coating, wehave tried to add new chemicals to nuclear emulsion gel
and optimize the gel’s viscosity. We were the first in theworld to succeed in the mechanical coating of over 60
μm thickness of nuclear emulsion films. We also
introduced new gel production machine that can make30 times amount of nuclear emulsion gel compared withconventional machine.
Now, we can make about 100 m2 nuclear emulsion
films per month.
We checked the performance of new emulsion gel
and films. The index of sensitivity is Grain Density(GD) which is number of silver grains in the tracks ofminimum ionized particle. The index of noise rate is
Fog Density (FD) which is number of randomly
generated silver grains unrelated to tracks. After we
exposed electron beam to emulsion films at UVSOR(Fig. 2), we evaluated GD and FD.
We checked that GD and FD of nuclear emulsion
gel and films which made by mass production facilities
are comparable to that of conventional products. And
the performance is stable for repeated operation. (Fig.
3, 4)

Ⅲ -1

Fig. 1. Overview of roll-to-roll coating machine in
Nagoya University.

Fig. 2. Optical microscopic image of electron beam
(several tens of MeV) track. The electron beam was
exposed at UVSOR.

Fig. 3. Difference of Grain Density (GD) by emulsion
gel batch.

Fig. 4. Difference of Fog Density (FD) by emulsion
gel batch.

35 3 Ⅲ01-

BL1U
Ⅲ -1. Accelerators
and Instruments

BL1U

Laser Pulse Shaping and Transport at UVSOR-III
Y. Takashima 1,2, A. Mano1, G. Jang2, Y. Taira3, M. Fujimoto3, Y. Okano3 and M. Katoh4,3Synchrotron Radiation Research Center, Nagoya University, Nagoya 464-8603, Japan
2
School of Engineering, Nagoya University, Nagoya 464-8603, Japan
3
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
4
HiSOR, Hiroshima University, Higashi-Hiroshima 739-0046, Japan1

Ⅲ -1

We constructed the compact optics to shape a laser
pulse to develop advanced Laser-Compton scattering
gamma-ray source or sophisticated laser-synchrotron
radiation combination experiment. The optics is a kindof Michelson interferometer [1]. As the first step, we
tried to generate two temporally consecutive laser
pulses (double pulse) from one original laser pulse. We
confirmed generating double pulses.
Figure 1 shows the optics for the generation of the
double pulse of the short-pulse laser. The original laser
pulse is injected from the direction of arrow 1 in Fig.
1. The laser pulse is divided into the orthogonal
direction "A" and "B" by the beam splitter in Figure 1;
the laser pulses are reflected by the mirror 1 and 2.
Mirror 2 is mounted on the movable stage so that thepath length of the laser pulse along to "B" can bechanged. The reflected pulses are mixed in the beam
splitter and go throw the direction "C", and thenreflected the mirror 3 and exit to the direction "D".
We used an autocorrelator to measure the pulse
width and the interval of the double pulses. The
autocorrelator is installed downstream of the direction"D". According to the measurement using the
autocorrelator, when we interrupt the laser pulse
reflected on mirror 1, the FWHM of the pulse width ofthe laser of the single pulse is about 5.0 ps. Figure 2
showed the output signal from the autocorrelator when

we arranged the difference of the path length
appropriately by moving the stage of mirror 2. We
obtained the interval of the double pulse of about 3.0
ps. Fig. 3. shows the spectrum of the double pulse laser.
We successfully transported the laser pulse onto thecirculating electron beam in the UVSOR-III storage
ring by using the existing laser transport line for theLaser-Compton scattering.

Fig. 2. The output signal of the autocorrelator.

Fig. 3. The spectrum of the double pulse laser.

Fig. 1. Optics for the generation of the double pulse.

[1] G. Jang, Graduation thesis of School of Engineering,
Nagoya University (2021)

36 4 Ⅲ01-

BL1U

Ⅲ -1. Accelerators and Instruments

BL1U

Revival of UVSOR-FEL and Gamma Ray Generation
by Intra-cavity Laser Compton Scattering
H. Zen1, J. Yamazaki2, M. Fujimoto2,3, K. Hayashi2, H. Ohta2, Y. Taira2,3 and M. Katoh2,4Institute of Advanced Energy, Kyoto University, Uji 611-0011, JapanUVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
3
The Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan
4
Hiroshima Synchrotron Radiation Center, Hiroshima University, Higashi-Hiroshima 739-0046, Japan
1

2

Compton scattering [2]. In this study, two small
current electron bunches were injected into 3 backets
behind the main bunches for generating gamma-ray by
colliding with intra-cavity FEL beams. The spectrumof the generated gamma-ray measured by a NaI
scintillator is shown in Fig. 2. The maximum gammaray energy was evaluated as 13 MeV. In thismeasurement, the optical cavity length was slightly
detuned to avoid the pile-up events in the scintillator.

Intensity [Arb. Units]

1.0
0.8
0.6
0.4
0.2
0.0
520

522

524

526

Wavelength [nm]

528

530

Fig. 1. Wavelength Spectrum and beam profile of
FEL observed at the downstream of the optical cavity.
100

Counts [# /s / 0.1 MeV]

The lasing of Free Electron Laser (FEL) at S5 section
was firstly achieved in 1992. The research activity
related to FEL had been continued until the end of
FY2011. Then the straight section used for activities of
FEL and coherent light source developments waschanged to S1, which has been newly created by moving
the injection point. Two APPLE-II type undulators with
an electromagnetic buncher magnet have been installedin the S1 section. The optical cavity used for FEL lasing
was removed from S5 section at the end of FY2010 andreconstructed at the beginning of FY2015. In FY2017,
we tried to have a first lasing of FEL at S1 section. At
that time, we could achieve storage of undulator
radiation in the optical cavity [1] but could not achieve
FEL lasing due to a mismatch between the optical cavity
length and the electron bunch interval. In the April-2021
shutdown of UVSOR, the position of the downstream
mirror chamber was shifted to make the roundtrip
frequency of the optical cavity the same as the electron
bunch interval. In February 2022, a commissioning
experiment of optical cavity and FEL was conducted toconfirm the FEL lasing at S1 section.
The commissioning experiment of FEL was performed
with an FEL cavity mirror pair which has highreflectivity around 520 nm. At first, the gap and thephase of the APPLE-II undulators are adjusted to havethe center wavelength of 520 nm with the electron beamenergy of 600 MeV. Next, the angles of the opticalcavity mirrors were adjusted to store the undulator
radiation in the optical cavity. Then the length of the
optical cavity was scanned for finding the matchingcondition between the roundtrip frequency of the opticalcavity and the electron bunch interval. This adjustment
was performed with two bunch equidistant filling mode.
The pulse duration of the stored light is strongly
depending on the cavity length. The cavity length
condition giving the shortest pulse duration of the stored
light should be corresponding with the matched
condition. After finding the matched condition of thecavity length, the electron beam current was increased
up to 20 mA/2 bunch and the excitation current of thebuncher magnet was increased up to 20 A. With a slightadjustment of the angle of the optical cavity mirror,
lasing of the FEL can be achieved. Figure 1 shows thephotograph of the FEL beam and its wavelength
spectrum. The bright green spot in the photograph was
the FEL beam having a central wavelength of 524.5 nm.
One of the interesting applications of UVSOR-FEL
is the gamma-ray generation by the intra-cavity laser

600 MeV, 524.4 nm
FEL bunch: 12.6 mA
LCS bunch: 3.9 mA
FEL Power: 0.3 mW
Collimator: 2.8 mm

80
60
40
20
0

0

2

4

6

8

10

Energy [MeV]12

14

Fig. 2. The spectrum of the generated gamma-ray
measured by a NaI scintillator.

[1] H. Zen et al., UVSOR Activity Report 2017 45(2018) 31.
[2] M. Hosaka et al., Nucl. Instrum. Meth. A 393 (1997)525.

37 5 Ⅲ01-

Ⅲ -1

BL1U
Ⅲ -1. Accelerators
and Instruments

BL1U

Evaluation of Analyzing Power of Gamma-ray Polarimeter
S. Endo1,2, T. Shizuma3, H. Zen4, Y. Taira5, K. Sugita5, O. Mohamed1, S. Kawamura2,
R. Abe2, T. Okudaira2, M. Kitaguchi2 and H. M. Shimizu2
Japan Atomic Energy Agency, Tokai 319-1195, Japan
2
Nagoya University, Nagoya 464-8062, Japan
3
National Institute for Quantum Science and Technology, Tokai 319-1195, Japan
4
Kyoto University, Uji 611-0011, Japan
5
Institute for Molecular Science, Okazaki 444-8585, Japan1

Ⅲ -1
A measurement of a circular polarization ratio of the
gamma-rays emitted from an un-polarized neutron
capture reaction of nuclei leads to the study for thecompound nuclei [1]. Furthermore, the total angularmomentum of neutron resonances can be determinedby measuring the circular polarization ratio of gammarays from a polarized-neutron capture reaction [2]. We
are aiming to conduct these measurements at JPARC/MLF. The degree of the circular polarization of
gamma-rays can be determined by measuring thetransmission ratio of the magnet, called a gamma-ray
polarimeter, because the cross-section of the Compton
scattering depends on the direction of the electron
polarization in the magnetized material and the
gamma-ray helicity, i.e., circular polarization [3]. We
developed a gamma-ray polarimeter and evaluated its
analyzing power using a circularly polarized gammaray beam generated by the inverse Thomson scatteringin the UVSOR BL1U [4].
The analyzing power is defined as�� ���

𝑃𝑃� � �� ��� ,where 𝑁𝑁 � and 𝑁𝑁 � are the transmission ratio of thepolarimeter for right- and left-circularly polarized
gamma-rays, respectively. Figure 1 shows the schematicof the experiment. The beam flux was monitored bydetecting gamma-rays scattered from brass with a LaBr
detector. Gamma-rays transmitting the polarimeter weredetected using a Ge detector. Figure 2 shows the
gamma-ray energy spectrum taken by the Ge detector.
Background measurement was performed with the laser
off. Therefore, it includes the environmental radiation
and backgrounds derived from the Bremsstrahlung. The
pile-up effect was corrected, and the transmission ratio
was obtained from the number of events for the LaBr
and Ge detectors.
Since the analyzing power depends on the magnetic
field, it depends on the current flowing the polarimeter.
Figure 3 shows the obtained analyzing power for eachcurrent for 100% circularly polarized gamma-rays.
The current up and down mean whether the current
was increased or decreased, respectively, reflecting theeffect of magnetic hysteresis. The analyzing power
was obtained as 𝑃𝑃� � 2.12 � 0.04% above 2 A.

Fig. 1. Schematic of experimental setup.

Fig. 2. Gamma-ray energy spectrum taken by the Ge
detector.

Fig. 3. Analyzing power for each current.

[1] V.V. Flambaum and O.P. Sushkov, Nucl. Phys. A
435 (1985) 352.
[2] L.C. Bindenharn et al., Phys. Rev. 83 (1951) 683.
[3] H.A. Tolhoek, Rev. Mod. Phys. 28 (1956) 277.
[4] Y. Taira et al., Nucl. Instrum. Meth. Phys. Res. A
637 (2011) 116.

38 6 Ⅲ01-

BL1U

Ⅲ -1. Accelerators and Instruments

BL1U

Development of Gamma ray Induced Positron Annihilation Spectroscopy
Y. Taira1,2, K. Sugita1,2, R. Yamamoto3, Y. Okano1 and T. Hirade4

UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
School of Physical Sciences, The Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan
3
Graduate School of Engineering, Nagoya University, Nagoya, 464-8603, Japan
4
Nuclear Science and Engineering Center, Japan Atomic Energy Agency, Tokai, 316-8511, Japan
1

2

Positron annihilation spectroscopy (PAS) is an
excellent method to detect lattice defects in solids suchas vacancies, dislocations, and clusters and freevolumes in polymers [1]. Conventional β+ radioisotopes
such as 22Na, a positron beam generated from anelectron accelerator, and a high energy gamma ray [2,3]are used for PAS. PAS using a high energy gamma ray,which is called gamma ray induced PAS (GiPAS), has
several advantages compared with PAS using
conventional radioisotopes. (i) It enables defect analysis
of a thick material in a few centimeters because
positrons are created throughout a bulk material via pair
production by irradiation with gamma rays having highpenetration into the material. (ii) Source contribution of
positrons annihilated in the covering material isnegligible. In conventional radioisotopes, about 10 % ~15 % of positrons annihilate in the source. This distorts
the positron lifetime spectra and complicates the data
analysis.
Inverse Thomson/Compton scattering is a scattering
process between high energy electrons and a laser,which can produce high energy gamma rays. A MeV
gamma ray can be generated by the scattering between a
1 GeV electron and a 1 eV photon. The generated gamma
rays possess features such as quasi-monochromatic andtunable energy, highly polarized, low divergence angle,
and low background. Inverse Thomson/Compton
scattered gamma rays have been generated at several
electron accelerator facilities in the world. We havedeveloped ultra-short pulsed gamma rays by inverse
Thomson scattering at UVSOR-III [4]. They are
generated via inverse Thomson scattering with 90
degree collisions between a 750-MeV electron beam
and a Ti:Sa laser pulse. The maximum energy is 6.6
MeV and the pulse width is calculated to be sub-ps to ps
ranges.
We are currently developing GiPAS using the ultrashort pulsed gamma ray [5]. Gamma ray induced
positron annihilation lifetime spectroscopy (GiPALS),
which is a technique to measure positron lifetime andevaluate type of defects at the nanometer scale andtheir concentrations inside material, is currently
available for users. The measured positron lifetime
spectrum of stainless steel distributed by National
Metrology Institute of Japan (NMIJ) as referencematerial for positron lifetime is shown in Fig. 1. The
positron lifetime spectrum was analyzed using LT9
program.
In addition to GiPALS, we have developed gamma

ray induced age-momentum correlation (GiAMOC),
which is a technique to measure time resolved
momentum distribution of an electron which is theannihilation counterpart of a positron. The measured
AMOC spectrum of the NMIJ stainless steel is shownin Fig. 2.

Fig. 1. Measured positron lifetime spectrum of NMIJ
stainless steel. Time resolution is 138 ps in full widthat half maximum.

Fig. 2. GiAMOC spectrum of NMIJ stainless steel.

[1] J. Cizek, J. Mat. Sci. Tech. 34 (2018) 577.
[2] F. A. Selim, Acta Phys. Pol. A 132 (2017) 1450.
[3] M. Butterling et al., Nucl. Instr. Meth. Phys. Res.
B, 269 (2011) 2623.
[4] Y. Taira et al., Nucl. Instr. Meth. A 652 (2011) 696.
[5] Y. Taira et al., Rev. Sci. Instr. 84 (2013) 053305.

39 7 Ⅲ01-

Ⅲ -1

BL1U
Ⅲ -1. Accelerators
and Instruments

BL1U

Single Electron Storage at UVSOR-III
R. Shinomiya 1, M. Shimada 2,3, H. Miyauchi 2,3, M. Fujimoto 4 and M. Katoh 3,1,4,2

School of Science, Hiroshima University, Higashi-hiroshima 739-8526, Japan
High Energy Accelerator Research Organization (KEK), Tsukuba 305-0801, Japan
3
Hiroshima Synchrotron Radiation Research Center, Hiroshima University, Higashi-hiroshima 739-0046, Japan
4
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
1

2

Ⅲ -1

Single electron storage in an electron synchrotron(electron storage ring) has been achieved at several
facilities, aiming to investigate electron dynamics in asynchrotron [1,2], to investigate electromagnetic
radiation from an electron [3,4], or to utilize theradiation as a primary standard [5,6]. However, in Japan,
as far as we know, there is no report on such studies.
We have tried the single electron storage at UVSORIII aiming to establish accelerator techniques for thisspecial operation mode toward novel experiments infuture.
The experimental procedure is as follows. First, we
accumulate an electron beam with relatively low current,
typically around 1 mA. Then, we reduce the beam
current by using a device called beam scraper, which isa movable copper rod installed on the beam pipe at astraight section. We can insert the rod into the beam pipe
close to the beam from the vertical direction. When we
make the distance between the rod and the beam around
1 mm, the beam lifetime becomes several minutes,
which is much shorter than the normal one, typicallyseveral hours. We observe the beam current by using
DCCT until around 0.1 mA. Below this beam current,
the DCCT cannot give reliable data. Then, we use aphotomultiplier tube (PMT) to measure the synchrotron
radiation intensity at BL1U, where ultraviolet radiation
can be produced from an undulator. The wavelength of
the fundamental radiation from the undulator was set tobe 355 nm. The PMT was set at a small dark room
surrounded by black curtains, where the undulator
radiation was extracted from the ultra-high vacuum
chamber of the beamline to the air through a sapphire
window. The signal from the PMT was analyzed with acounting unit and was recorded by a PC. We tried toapply various bandpass filters to improve the signal tonoise ratio. We found that a bandpass filter which had amoderately large bandwidth of about 60 nm and passed
almost all the fundamental component of the undulator
radiation gave the best result.
We mounted four ND filters with OD 2.0 on the PMTat the start of the measurement. As decreasing the beam
current, we removed them one by one as keeping thecounting rate of PMT lower than the limit of theprocessing rate of the counting unit. After removing all
the ND filters, we successfully observed step-functionlike jumps in the time history of the counting rate as
shown in Fig. 1, which indicated the loss of the electrons
one by one. The background rate is much smaller than
the step of the counting rate, which corresponds to theradiation intensity emitted from one electron. The
observed counting rate from one electron was consistent
with a preliminary evaluation of the photon flux basedon an analytic formula.
We do not describe the details here, but we also
succeeded in observing which RF backet the lastelectron existed in. Moreover, after confirming that
only one electron is circulating, we pulled out thebeam scraper and observed that the last electron wasstored for more than 2 hours, which is sufficiently longto carry out the experiments with single electron.
In conclusion, we successfully demonstrated thesingle electron operation at UVSOR-III and establish
the basic techniques for this special operating mode.
We are going to start novel researches utilizing thisnew mode.

Fig. 1. Synchrotron radiation intensity at BL1U.

[1] A. N. Aleshaev et al., NIM A 359 (1995) 80.
[2] I. V. Pinayev et al., NIM A 375 (1996) 71.
[3] I. V. Pinayev et al., NIM A 341 (1994) 17.
[4] A. Romanov et al., JINST 16 (2021) P12009.
[5] R. Klein et al., Phys. Rev. STAB 11 (2008) 110701.
[6] R. Klein et al., Metrologia 47 (2010) R33.

40 8 Ⅲ01-

BL1U

Ⅲ -1. Accelerators and Instruments

BL1U

Exploring Novel Application of Undulator Radiation Based on
Interferometric Technique
K. Kato1, M. Shimada2,3, H. Miyauchi2,3, A. Mano4 and M. Katoh3,1,5,2,4

School of Science, Hiroshima University, Higashi-hiroshima 739-8526, Japan
High Energy Accelerator Research Organization (KEK), Tsukuba 305-0801, Japan
3
Hiroshima Synchrotron Radiation Research Center, Hiroshima University, Higashi-hiroshima 739-0046, Japan
4
Synchrotron Radiation Research Center, Nagoya University, Nagoya 464-8603, Japan
5
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan1

2

The classical electromagnetic theory indicates thatradiation from a relativistic electron running in an
undulator forms a wave packet whose number ofcycles is exactly same as the number of magnetic
periods of the undulator. In case of the undulator at
BL1U, the number of the magnetic period is 10. If we
set the wavelength of the fundamental radiation at 355
nm, then the wave packet has a length of 3.5 micron
which corresponds to about 10 femtosecond. This“ultrafast” property of synchrotron radiation has
merely been considered useful for any applications
except for only a few previous works [1]. However,recently, at UVSOR, interesting applications of thisproperty has been demonstrated successfully [2,3,4].
Following these successes, we continue exploringother possible applications. We were inspired by aprevious study using interferometer, in which theundulator radiation showed a clear interferogram [5].
We started considering an application to the tomographic
imaging. In the optics technology field, a technology
called optical coherence tomography has beensuccessfully demonstrated and are widely usedparticularly in the medical field [6]. Its principle may bedescribed as follows. A low coherence light beam splits
into two by means of a beam splitter. Two beams arereflected by mirrors and come back to the beam splitterand merge. When the path lengths are exactly same,interference fringe is observed in the merged beam. If asample material is inserted on a path, because of therefractive index of the sample, the path length which
gives the interference changes. Moreover, if multireflection takes place in the sample, interference isobserved at several different path lengths. From suchobservation, one can get information on the inner
structure and its optical property of the sample. We havecarried out a proof of principle experiment on such atomography method using undulator radiation at BL1U[7]. Some preliminary results are presented here.
The wavelength of the undulator radiation was
selected at 355 nm, which is compatible with thewavelength range of the Mach–Zehnder interferometer,
which was constructed in a previous study [5]. We
utilized the existing interferometer to observe thechange of the interferogram as putting samples on its
light paths. We tried two configurations, transmitting
and reflecting ones. To minimize the modification of
the interferometer, in the former configuration, we justplaced the sample on the one of the path after the beam
splitter, and, in the latter, we placed the sample at thereflecting mirror.
We carried out the interferogram measurements onsome thin materials such as glass plates or films andseveral stimulated samples which has multilayer
structure. One example of the interference fringe isshown in Fig. 1. In this measurement, a thin film is placedin a transmitting configuration. The sample covered ahalf of the light path. By adjusting the optical path
length, we could observe interference fringe only for thehalf area where the film existed. More details will bepresented in future papers.

Fig. 1. Interference fringe observed for 25 micron
OPP film as a sample. In the upper side, the OPP filmis placed and in the lower none.

[1] S. Nakanishi et al., J. Synchrotron Rad. 5 (1998)
1702.
[2] T. Kaneyasu et al., Phys. Rev. Lett. 123 (2019)
233401.
[3] Y. Hikosaka et al., Nature Comm. 10 (2019) 4988.
[4] T. Kaneyasu et al., Phys. Rev. Lett. 126 (2021)
113202.
[5] e.g. D. Huang et al., Science 254 (1991) 1178
[6] A. Mano et al. UVSOR Activity Report 2020 48(2021) 38.
[7] K. Kato et al., presented at JSR 2022 (2022).

41 9 Ⅲ01-

Ⅲ -1

BL2A
Ⅲ -1. Accelerators
and Instruments

BL2A

Calibration of CMOS Sensor with Reflective-type Flux Reduction System
N. Narukage

National Astronomical Observatory of Japan, Mitaka 181-8588, Japan

Ⅲ -1

The solar corona is full of dynamic phenomena suchas solar flares. The understandings of these phenomena
have been progressing step-by-step with the evolutionof the observation technology in EUV and X-rays fromthe space. But there are fundamental questions remainunanswered or haven’t even addressed so far. Ourscientific objective is to understand underlying physics
of the dynamic phenomena in the solar corona, coveringsome of the long-standing questions in solar physics
such as particle acceleration in flares and coronalheating. To achieve this objective, we identify theimaging spectroscopy (the observations with spatial,
temporal and energy resolutions) in the soft X-ray range(from ~0.5 keV to ~10 keV) is a powerful approach forthe detection and analysis of energetic events [1]. This
energy range contains many lines emitted from below 1
MK to beyond 10 MK plasmas plus continuum
component that reflects the electron temperature.
The soft X-ray imaging spectroscopy is realizedwith the following method. We take images with ashort enough exposure to detect only single X-ray
photon in an isolated pixel area with a fine pixel
Silicon sensor. So, we can measure the energy of the
X-ray photons one by one with spatial and temporal
resolutions. When we use a high-speed soft X-ray
camera that can perform the continuous exposure witha rate of more than several hundred times per second,
we can count the photon energy with a rate of several
10 photons / pixel / second. This high-speed exposure
is enough to track the time evolution of spectra
generated by dynamic phenomena in the solar corona,
whose lifetimes are about form several ten seconds toseveral minutes. For the first imaging spectroscopic
observation of the solar corona in soft X-ray range, welaunched a NASA’s sounding rocket (FOXSI-3) on
September 7th, 2018 and successfully obtained theunprecedented data [2] using a high-speed X-ray
camera [3] with a back-illuminated CMOS sensor [4].
Calibration of CMOS detectors is essential forscientific data analysis. For this purpose, a completely
monochromatic X-ray light source is needed. In
addition, the flux must be adjusted so that individual
X-ray photons can be isolated. Therefore, so far, wehave controlled (reduced) the flux by adjusting thematerial and thickness of metal filters. However, in
this case, the lower energy was preferentiallyattenuated, so the contamination of higher-order (2nd,
3rd and 4th order) components could not be removed,
resulting in incomplete data for calibration.
In this time, we developed a mirror-based reflectivetype flux reduction system (see Fig. 1). In this system,
two flat mirrors aligned in parallel are mounted on arotating stage, and by changing the angle of incidence,
the reflectance, i.e., attenuation rate, can be flexibly

adjusted. The system worked well as expected andsuccessfully produced the completely monochromatic
light with the appropriate flux. As a result, theresponse of the CMOS detector used in the FOXSI-3
sounding rocket project could be completely
calibrated in the energy range of 830 eV to 4500 eV in
50 eV intervals (see Fig. 2).

Fig. 1. Photo (left) and schematic
drawing (right) of the reflectivetype flux reduction system.

Fig. 2. Measured (black data points) and modeled(colored lines) response of the CMOS sensor to themonochromatic X-rays (at 2905.1 eV in this case).
[1] N. Narukage et al., White paper of the “soft X-ray
imaging spectroscopy”, arXiv:1706.04536 (2017).
[2] N. Narukage and S. Ishikawa, UVSOR Activity
Report 2018 46 (2019) 36.
[3] S. Ishikawa et al., Nuclear Instruments andMethods in Physics Research Section A, 912 (2018)
191-194.
[4] N. Narukage et al., Nuclear Instruments andMethods in Physics Research Section A, 950 (2020)
162974.

42 10 Ⅲ01-

BL3B

Ⅲ -1. Accelerators and Instruments

BL3B

Photon Energy Resolutions of BL3B Evaluated by Appearance Energy
Measurements of Xe+ Ions
H. Iwayama1,2

UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
School of Physical Sciences, The Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan1

2

A beamline in s synchrotron facility generally works
as a monochromator and focus system. A photon
energy resolution of the beamline is one of the mostimportant parameters for various measurements. To
maintain the performance of the beamlines, it isdesirable to check the actual photon energy resolution
regularly.
The beamline BL3B can provide monochromatic
light in the range from visible to extreme ultraviolet
region. Previously the photon energy resolution of
BL3B was evaluated by vibration-rotation spectra ofoxygen molecules [1], which are significantly complex.
In this work, we estimate photon energy resolutions of
BL3B from appearance energy spectra, which havestep functional structure at an ionization threshold.
The photoelectron-photoion coincidence (PEPICO)
measurements for an ion time-of-flight mass spectrum
were performed at UVSOR BL3B. A schematic view of
PEPICO measurements is described in the previous
report [2]. Sample gas is xenon, whose ionizationthreshold is 12.130 eV [3]. The ion mass spectra wererecorded at photon energies ranging from 12.100 eV to
12.200 eV in 0.001 eV-increments. We used G1 gratingof BL3B. We estimate photon energy resolutions forthree slit configurations of (entrance slit, exit slit) = (500μm, 500 μm), (300 μm, 300 μm) and (100 μm, 100 μm).
Figure 1 shows a typical mass spectrum of Xe ions.
The peak structure results from an isotope distributionof Xe atoms. The corresponding mass resolution
m/Δm is 400.
Figure 2 shows Xe ions yield spectra for three slit
configurations. We find steep rises at the ionizationthreshold of 12.130 eV. With narrowing slit sizes, stepsof Xe ion yield spectra become steeper. This showsthat photon energy resolution become better. From
three spectra, we estimate photon energy resolutions
for three slit configurations and summarize Table 1. In
future, we also perform estimations of photon energy
resolutions for G2 and G3 gratings.

Ⅲ -1

Fig. 1. Typical time-of-flight mass spectrum of Xe ions.

Fig. 2. Xe ion yield spectra around the ionizationenergy of 12.130 eV for three slit configurations.
Table 1. Photon energy resolutions for G1 grating
Slit size(500 μm, 500 μm)(300 μm, 300 μm)(100 μm, 100 μm)

ΔE @ hv=12eV
20 meV
11 meV
4.2 meVE / ΔE
600
1000
3000

[1] K. Fukui, et al., J. Synchrotron Rad. 21 (2014) 452.
[2] H. Iwayama and T. Horigome, UVSOR Activity
Report 2020 48 (2021) 41.
[3]https://physics.nist.gov/PhysRefData/ASD/levels_
form.html.

43 11 Ⅲ01-

BL4B
Ⅲ -1. Accelerators
and Instruments

BL4B

BL4B Usage for Developing the Photoelectron Spectroscopy End-station for
Organic Materials
K. Fukutani, H. Iwayama, F. Matsui and S. Kera
Institute for Molecular Science, Okazaki 444-8585, Japan

Ⅲ -1

The field of organic electronics has been prolific in
the last couple of years. However, the study of themolecular function and property using the synchrotron
light sources has been limited so far due to difficulty inthe measurements for irradiation sensitive materials andlack of the suitable environment for the comprehensive
experiments.
The soft X-ray beamline BL4B, monochromator was
designed to cover the energy range of 35 – 800 eV andused for XMCD and XAS by setting the user apparatus.
To achieve the fundamental understanding of chargetransport properties, adsorption properties, interface
energetics, chemical reactivity and so on, we placed theend-station with the acceptance-cone- tunable electron
spectrometer (ACTES) for the highly efficient constantenergy photoelectron mapping based on the ARPES
system equipped with a hemispherical analyzer (MBSA-1 Lens4) [1].
In the initial process, we tested the figure of meritfor a typical experimental procedure, that is core-level
photoelectron spectroscopy, valence band energyband dispersion measurement, low-energy secondary
electron cut-off measurement with bias voltage, andnear-edge X-ray absorption fine structure (NEXAFS)
spectroscopy. The samples of Au(111) and molecular
films of OV-phthalocyanine (OVPc) are prepared.
The photon flux is moderate at BL4B, however it isstill high enough to make some troubles on the sample
of organic films, like an irradiation damage. We havechecked a typical measurement condition of photon
flux and analyzer parameters with energy resolution
and spectral intensity for optimizing the molecularsystems. The beam-spot size was set at 0.68 x 0.52 mm
at photon energy (hv) of 60 eV with a resolution power(E/ΔE) of 5,000. Effective low-hv range could startfrom 30 eV, and it would be very hard to obtain the
results at 25 eV for ARPES experiments. The high-hv
range could be useful up to 1,200 eV for XPS
experiments, though the monochromator covers up to
1,500 eV. The contribution of the second-order light isestimated less than 1 % for hv = 250 eV at the E/ΔE of
2,000 for grating G1.
XAS was demonstrated for C-, N-, and O- K edges. A
large photon-flux dropping due to a mirror contamination
is observed for C-K edge region, and the NEXAFS
experiments for bulk samples could be reasonable bychanging the irradiating position slightly for recording
the data by using a relatively clean area of the gratings,
however we request to clean up the mirror systems.
Moreover, the reference data of Au mesh must be
clarified to obtain the data for thin-film interfaces.
The beam stabilities of the photon energy and flux

have been carefully checked by repeatedly measuring
the binding energy and intensity of Au 4f and Fermiedge. The result confirms that the light will bestabilized after about 1 hour. The continuous scanning
for accumulating the data long time under the lowphoton flux should be confirmed again.
The beam damage on the molecular film sample ischecked for the annealed monolayer of OVPc
/Au(111) with hv = 60eV at the E/ΔE of 2,000, which
gives the sample current (Is) of 5.2 nA (corresponding
to the Au mesh current (I0) of 167 pA). We observed
discernible broadening of the HOMO spectral feature
over the 2 h irradiation as shown in Fig. 1. We find theirradiation effects are settled by reducing the photon
flux to the Is = 0.55 nA to give no remarkable change
in the features over 40 min. The impact will depend on
the hv range, hence the molecular film survived for 60
min. in XPS for hv = 500 eV at the E/ΔE of 2,000,
giving the Is = 0.28 nA (I0 = 32 pA), but not suitable
for a higher-photon flux of Is = 0.77 nA (I0 = 85 pA) as
an example.
The detailed experiments upon cooling the sample
will be continued in FY2022.

Fig. 1. Impacts of irradiation time on the ARPES of amonolayer of OVPc/Au(111) surface taken at 295 K
and hν = 60 eV.
[1] H. Yamane et. al., Rev. Sci. Instrum. 90 (2019)093102.

44 12 Ⅲ01-

BL4B

Ⅲ -1. Accelerators and Instruments

BL4B

Development of High Efficiency Liquid Cell in Total Electron Yield Using
Atomically-thin Graphene
I. Mitsuishi1, K. Kashiwakura1, Y. Niwa1, T. Ogawa1, Y. Tawara1, R. Kitaura2,
P. Solís-Fernández3, K. Kawahara3, H. Ago3, T. Taniguchi4, K. Nomoto4, H. Kodaka4,
T. Horigome5, E. Nakamura5, H. Iwayama5, M. Nagasaka5 and K Tanaka5
Graduate School of Science, Division of Particle and Astrophysical Science, Nagoya University,
Nagoya 464-8602, Japan2
Department of Chemistry, Nagoya University, Nagoya 464-8602, Japan3
Global Innovation Center, Kyushu University, Kasuga 816-8580, Japan
4
Optical Measurement Technology Development Department, R&D Division, USHIO INC.,
Yokohama 225-0004, Japan
5
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan

X-rays are a powerful probe to investigate material
properties through, e.g., X-ray absorption
spectroscopy (XAS) which can reveal local atomic andelectronic states of oxygen, carbon, etc.. Among the
XAS methods for liquid, total electron yield ispreferably utilized in some cases because shortelectron escape depth in this method makes it possible
to examine atomic and electron states of liquid surface
and solid-liquid interfaces. In order to realize highefficiency measurements through the total electron
yield method, high efficiency films with high electrontransmission are a key and therefore have beenstrongly desired.
To construct our original device for the total electron
yield measurements, we propose to utilize graphene
which is atomically thin and has high electrontransmission [1]. As a first step, we tried to establish our
original experimental setup to verify our idea as shownin Fig. 1. As a preliminary experiment, liquid water was
sandwiched by a silicon nitride window and freestanding 5-layer graphene on a quartz substrate withapertures of 0.5 x 0.5 mm. A high voltage system wasalso prepared between the entrance window of thesample and the X-ray source to reduce thecontamination of electrons produced by the surface ofthe substrate and sample holder. We obtained the spectra
around the O K-edge structure as shown in Fig. 2 andconfirmed the O K-edge absorption by the liquid water.
However, photoelectrons of oxygen were also detectedin background spectra without the sample. Thus, toreduce the contamination, voltages of 200, 400, 600,
and 800 eV were applied and the reduction of thecommination was confirmed successfully as shown in
Fig. 2. Although the high-voltage system worked welland the contamination level went down significantly,
we could not conclude that there is no significant
contribution to the observed photoelectrons with thesample. Thus, to evaluate the sensitivity of our liquid
cell, optimizations of our experimental setup based on
simulations are necessary.

Entrance

X-ray

Exit

Ⅲ -1

X-ray
Sample stage (Z-axis)

MCP
SamplePD
X-ray

Fig. 1 Experimental setup and an overview of thesample holder.

With the sample

105

Background(Without the sample)

104

0V
200 V

Intensity

1

400 V
600 V

103

800 V
102

500

520

Energy [eV]

540

560

Fig. 2 Examples of observed MCP spectra aroundthe O K-edge structure with / without the sample. The
spectra with voltages of 200, 400, 600, 800 eV are also
shown for comparison.

[1] G. Hassink, R. Wanke, I. Rastegar, W. Braun, C.
Stephanos, P. Herlinger, J. H. Smet and J. Mannhart,
APL Materials 3 (2015) 076106.

45 13 Ⅲ01-

BL5B
Ⅲ -1. Accelerators
and Instruments

BL5B

Development of a Fluorescence Polarimeter in Extreme Ultraviolet Region
T. Kaneyasu1, K. Hosaka2 and J. Adachi3

SAGA Light Source, Tosu 841-0005, Japan
National Institutes for Quantum Science and Technology, Takasaki 370-1292, Japan
3
Institute of Materials Structure Science, KEK, Tsukuba 305-0801, Japan
1

2

Ⅲ -1

Polarization is one of the most important characteristics
of synchrotron radiation. In addition to the use ofhorizontal linear polarization in the bending magnet
radiation, the recent advent of insertion devices allows
us to use arbitrarily polarized light in a wide spectral
range from vacuum ultraviolet to x-ray. For accurate
measurements using the polarization properties ofsynchrotron radiation, it is essential to evaluate thepolarization state of light at a sample point. Here, we
present a polarization measurement of synchrotron
radiation in the extreme ultraviolet (XUV) wavelength
region using a fluorescence polarimeter. This method isbased on the conversion of the XUV radiation to visible
radiation on the atomic resonance [1-3]. The fluorescencepreserves the polarization state of the excitation lightwhen it is observed along the light propagation axis.
Comparing with the optical polarimeters [3], thismethod has advantages in its simple apparatus and easy
operation.
The experiment was performed at the bending
magnet beamline BL5B in UVSOR synchrotron. Figure
1 shows the experimental layout of the present study.
The monochromatized synchrotron radiation interactedwith helium atoms provided by an effusive beam. The
pressure of the interaction chamber was around 1×10-3
Pa during the measurement. The excitation wavelength
was 51.56 nm, corresponding to the 1s5p resonance of
helium atom. We observed 361-nm-wavelength
fluorescence photons emitted in decays from 1s5p to
1s2s state of a helium atom. The fluorescence photons
emitted parallel to the light propagation axis (z-axis)
were detected by a photomultiplier tube equipped witha polarizer and a bandpass filter. To evaluate thepolarization state of XUV radiation, we measured
fluorescence intensity as a function of the rotation angleof the polarizer.
Figure 2 shows the fluorescence intensity measured
as a function of the polarizer angle which is defined by
the angle of the polarization axis with respect to thehorizontal axis (x-axis). The fluorescence intensity
shows a sinusoidal modulation reflecting the polarization
state of the XUV radiation. Assuming an ellipticalpolarization, the experimental data points are fitted by atheoretical curve. The linear polarization degree of lightis evaluated to be 0.74 which is somewhat smaller than
the ideal value of 0.84 [4]. This disagreement is probably
due to the detection solid angle for the fluorescencephotons, and it is expected that this instrumental effectcan be improved by reducing the detection solid angle.

The present work shows the capability of a fluorescencepolarimeter to evaluate the polarization state of XUVradiation. Although we evaluated the degree of linear
polarization only, this method has the potential todetermine Stokes parameters [3] by just introducing aquarter waveplate in the detector system.

Fig. 1. Experimental layout of the present study. The
fluorescence photon emitted along the light propagation
axis was detected.

Fig. 2. Fluorescence intensity measured as a functionof the polarizer angle. The experimental data points
are fitted by a theoretical curve.

[1] V. Bobahev and O. S. Vasyutinkii, Rev. Sci. Isturm.
63 (1992) 1509.
[2] C. J. Latimer et al., J. Electron Spectroscopy Relat.
Phenom. 101-103 (1999) 875.
[3] E. Allaria et al., Phys. Rev. X 4 (2014) 041040.
[4] Y. Hikosaka et al., J. Synchrotron Rad. 27 (2020)
675.

46 14 Ⅲ01-

BL5B

Ⅲ -1. Accelerators and Instruments

BL5B

Measurement of a Detection Efficiency of High-sensitivity Microchannel
Plates with Tapered Pores
S. Matoba1, H. Iwayama2,3 and T. Kaneyasu4

Institute of Materials Structure Science, KEK, Tsukuba 305-0801, Japan
Editorial Board, UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan3
School of Physical Sciences, The Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan
4
SAGA Light Source, Tosu 841-0005, Japan
1

2

A microchannel plate (MCP) is a lead glass detector
with a two-dimensional array of electron-multiplying
pores of about 10 μm in diameter. When charged
particles or short-wavelength photons collide with theinner wall of the pore, secondary electrons are generated
and amplified in the pore to be detected as electron
pulses. MCPs are used in a very wide range of fields
from basic research to industry because of their large
area, high spatial resolution, and high-speed detection
capability. The maximum detection efficiency of an
MCP is at the upper limit of its open-area-ratio, andtypical MCPs have a detection efficiency of 50-60%.
This causes a problem of reduced detection efficiency
when used in coincidence measurement experiments.
For example, if an MCP with a detection efficiency of
60% is used in a triple coincidence experiment, the total
detection efficiency drops to about 20%. We havedeveloped a tapered MCP with an effective aperture of
89% by applying a tapered aperture to the incident area,
based on the idea that the detection efficiency can beincreased by increasing the aperture. The maximum
detection efficiency of the tapered MCP for monatomic
ions was improved to 90%, comparable to the openarea-ratio, demonstrating for the first time theeffectiveness of tapered processing in the detection ofmonatomic ions [1]. MCPs are also used as UV and Xray detectors, and are employed as imaging elements forplanetary atmosphere observation from satellites andspacecraft. It is known that a CsI coating on the surface
of an MCP improves the detection efficiency by several
tens of times in the wavelength region above 100 nm,
but below 100 nm, where emission lines from heliumand oxygen ions, which are major components of many
astronomical atmospheres, are concentrated, theimprovement is only 1.2 times [2]. Therefore, it is not adecisive observation method for understanding the
dynamic picture of celestial atmospheres. In thisexperiment, the detection efficiency of EUV ismeasured using a tapered MCP to verify its usefulness.
The wavelength range of about 32-190 nm was used forthe measurement. Spectrified EUV passes through apinhole with a diameter of 1 mm and is injected into the
MCP. Since the counting rate of the MCP saturates athigh intensity, a molybdenum mesh and a Kapton thinfilm were used to attenuate the light. A 300-nm-thickaluminum foil was inserted to attenuate higher-order
light. The MCP used for the measurement is a custommade type divided into four regions: normal type,tapered type, CsI-coated normal type, and CsI-coatedtapered type.
Figure 1 shows the intensity ratios of the measured
count rates of tapered MCP (T-MCP), CsI-coated MCP(CsI-MCP), and tapered CsI-coated MCP (TCsI-MCP)
to normal-type MCP (N-MCP). The detection efficiencyof the tapered MCP is higher than that of the normal
MCP in all the measured wavelength ranges. In the
short wavelength range, the tapered MCP has a higher
detection efficiency than the CsI-coated MCP. The
synergistic effect of tapered MCP and CsI coating on
the detection efficiency of MCP was confirmed. These
results demonstrate that tapered MCP is a powerfultool for UV detection.

Fig. 1. intensity ratio of measured count rates oftapered MCP (T), CsI-coated MCP (CsI) and tapered
CsI-coated MCP (TCsI) to normal type MCP (NMCP).

[1] S. Matoba et al., Jpn. J. Appl. Phys. 50 (2011)
112201.
[2] K. Yoshioka et al., Rev. Sci. Instrum. 83 (2012)083117.

47
III 01- 15 -

Ⅲ -1

BL5B
Ⅲ -1. Accelerators
and Instruments

BL5B

Study on the Source of Photon-Energy Drift of BL5B
H. Zen1, E. Nakamura2, K. Hayashi2 and K. Tanaka2,3Institute of Advanced Energy, Kyoto University, Uji 611-0011, JapanUVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan3
School of Physical Sciences, The Graduate University for Advanced Studies (SOKENDAI) Okazaki 444-8585, Japan12

M1 Holder Temp. [deg. C]

mechanics are considered to be a significant source ofthe photon-energy drift of BL5B. Further study should
be conducted to clarify whether the grating and its
holding mechanics are the significant sources of thephoton-energy drift or not.
60
50

2/25
Turn off Heateron M1 Holder

2/24
2/23

30

Turn on Heateron M1 Holder
Decrease Mirror Temp.
by Reducing SR amount on M1

09 10 11 12 13 14 15 16 17 18 19 20 21 2275

M1 Mirror Temp. [deg. C]

w/o M1 Mask

40

(a)

70

Time [hh]Turn off Heater on M1 Holder

2/25

w/o M1 Mask

65

2/23

60
55
50
45

Decrease Mirror Temp.
by Reducing SR amount on M1

40

2/24

Turn on Heateron M1 Holder

35

30
09 10 11 12 13 14 15 16 17 18 19 20 21 22

(b)

17.06
17.05

Wavelength [nm]Ⅲ -1

The stability of the photon beam properties, such as
beam position, beam intensity, photon energy, and soon, during user operation in beamlines, are very
important for the advanced application of synchrotron
radiation (SR) facilities. A photon-energy drift at
BL5B has been observed during user experiments [1].
We started the study on the source of this photonenergy drift in 2019. Although we have tried several
countermeasures to suppress the photon-energy drift[2], no significant improvement has been achieved.
In the study performed FY2020, we found a clear
correlation between the temperature of the M1 mirror
holder and the photon energy [3]. Therefore, in this FY,
a heater attached directly to the M1 mirror holder was
introduced to control the temperature of the M1 mirror
holder. By using the heater, the temperature of the M1
mirror holder can be stabilized as shown in Fig. 1 (a)black line. However, even with the stabilized M1
temperature, the wavelength of the SR exit the
monochromator continuously changes as shown in Fig.
1 (c) black line and red line.
To find the origin of the photon-energy drift, several
trials were made; 1: Turn off and on the heater on M1
holder, 2: Remove M1 mask to increase the M1 holder
temperature, 3: decrease mirror temperature by reducing
SR amount on M1 and successive optics. By trial 1, we
could confirm the correlation between M1 holder
temperature and the photon energy. By trial 2, wefound that the temperature variation of the M1 holder
has no significant influence on the trend of photonenergy drift. By trial 3, we found that the variation of
SR amount has a significant influence on the photon
energy drift. After reducing the SR amount, thetemperature of the M1 mirror gets stable within 3
hours (see Fig. 1 (b) red line) but the photon-energy
drift last for longer than 6 hours (see Fig. 1 (c) red line).
These results imply that the significant source of thephoton-energy drift should exist after the M1 mirror.
We checked our results obtained in FY2019. In
FY2019, grating #3 and mirror #23 (configuration ofG3M3) were used and roughly 0.1 eV photon-energy
drift was observed from 12 to 21 o’clock. In this FY,
roughly 0.24 eV photon-energy drift was observed
from 12 to 21 o’clock with grating #2 and mirror #24(G2M4). The sensitivity of the photon energy to the
angular variation for the G2M4 configuration isapproximately 1.2 times higher than that of the G3M3
configuration. The observed difference of photonenergy variation was much larger than the differenceof sensitivity. From this result, grating and its holding

17.04
17.03

Time [hh]Turn on Heateron M1 Holder
Turn off Heateron M1 Holder

17.02 w/o M1 Mask
17.01
17.00
16.99

2/25
2/23
2/24

Decrease Mirror Temp.
by Reducing SR amount on M1

16.98
16.97
09 10 11 12 13 14 15 16 17 18 19 20 21 22(c)Time [hh]Fig. 1. Trend of (a) temperature of M1 mirror holder,(b) temperature of M1 mirror, and (c) wavelength of
SR light exit monochromator of BL5B.

[1] K. Hayashi, UVSOR Activity Report 2011 39 (2012)121.
[2] H. Zen et al., UVSOR Activity Report 2019 47(2020) 42.
[3] H. Zen et al., UVSOR Activity Report 2020 48(2021) 47.

48
III 01- 16 -

BL7B

Ⅲ -1. Accelerators and Instruments

BL7B

Complex Refractive Index Measurement by Reflectance Spectra in
Different Polarization Configurations
M. Horiba1, K. Fukui1, K. Yamamoto1 and T. Saito2

Department of Electrical and Electronics Engineering, University of Fukui, Fukui 910-8507, Japan
Department of Electrical and Electronic Engineering, Tohoku Institute of Technology, Sendai 982-8577, Japan
1

2(Stokes parameter S1/S0 ~ 0.8), reflectance measured in
the horizontal and the vertical configuration are almost
equal to the reflectance of p- and s-polarization,
respectively.
The reliability of complex refractive index derived
from experimental values is directly related to themagnitude of the difference in reflectance in p- and spolarization configuration. Therefore, the angle ofincidence should be close to Brewster's angle, andexperiments have confirmed that the difference inreflectance spectra between the p- and s-polarization
configuration increases in the order of 8°, 45°, and 67°
angle of incidence. Therefore, results for 45° and 67°
are used for analysis. Figure 1 shows the photon
energy dependence spectra of complex refractive
index of Au mirror. The curves represent refractive
index n and extinction coefficient k derived from PS
method, and symbols from spectroscopic ellipsometry
measurement mode. The overall trend of n and kspectra from PS method are in good agreement withthose from spectroscopic ellipsometry measurement
mode. However, a marked difference in absolutevalues remains an issue to be solved.
3.0

Complex refractive index

Based on the basic design of the instrument by the
AIST group [1], we have been developing a complex
type refractive index spectrum measurement device(CRIMS-VUV) [2], which can continuously measure
not only in the visible region but also in the ultraviolet
and vacuum ultraviolet regions. CRIMS-VUV canperform spectroscopic ellipsometry measurements andreflection spectrum measurements under the sameenvironment.
The spectroscopic ellipsometry measurement modeof CRIS-VUV has the advantage of measuring thecomplex refractive index with high accuracy. However,this mode has the disadvantage that, due to its
measurement principle, it takes time to measure ateach measurement point (photon energy), making it
difficult to measure a continuous spectrum. In thisrespect, reflection spectrum measurement mode issuitable for measuring continuous spectrum. The wellknown Kramers - Kronig analysis method is used todetermine the complex refractive index spectrum fromthe reflectance spectrum. However, Kramers - Kronig
analysis method requires appropriate approximations
on both sides of the measured photon energy range,
since Kramers - Kronig analysis method uses theintegral of reflectance at photon energy from 0 to
infinity to obtain complex refractive index at eachphoton energy. Therefore, this method is useful, forexample, for obtaining qualitative complex refractive
index spectrum for limited photon energy region
around the absorption edge, but is not well suited for
obtaining quantitative complex refractive index
spectrum over a wide photon energy region. Unlike the
Kramers - Kronig analysis method method, there are
two methods to obtain the complex refractive index ateach photon energy from reflectance measurements
under different measurement conditions, one withreflectance measurements at different incident angles
and the other with different polarization configurations.
Therefore, we decided to use a method of measuringreflectance with p- and s-polarization configurations(PS method) to obtain the complex refractive index foreach photon energy, since CRIMS-VUV has amechanism that automatically changes the polarization
configuration as desired. In this report, we show the trial
results of PS method measurements on an Au mirror asa sample.
PS method measurements were carried out withCRIMS-VUV installed at BL7B. The photon energy
range was 2 to 20 eV. Since output light of BL7B (input
light of CRIMS-VUV) is highly linearly polarizedn (PS method)k (PS method)n (SE mode)k (SE mode)

2.5
2.0
1.5
1.0
0.5
0.0

2

4

6

8

10

12

14

16

18

20

Photon Energy (eV)Fig. 1. Complex refractive index of Au mirror[1] T. Saito, M. Yuri and H. Onuki, Rev. Sci. Instrum.
66 (1995) 1570.
[2] D. Imai et al., UVSOR Activity Report 2018 46(2019) 39.

49
III 01- 17 -Ⅲ -1

UVSOR User 3

Ⅲ-2

Materials Sciences

BL1UⅢ -2. Materials Sciences

BL1U

Study on Defects in Iron Formed under Hydrogen Embrittlement
Environment Using In-Situ Measurement Technique ofGamma-Ray Induced Positron Annihilation Lifetime Spectroscopy
A. Yabuuchi1, T. Hirade2, M. Fujinami3, R. Awaji3, N. Oshima4, K. Takai5, K. Sugita6
and Y. Taira6
Institute for Integrated Radiation and Nuclear Science, Kyoto University, Kumatori 590-0494, Japan
2
Nuclear Science and Engineering Center, Japan Atomic Energy Agency, Tokai 319-1195, Japan3
Department of Applied Chemistry and Biotechnology, Chiba University, Chiba 263-8522, Japan
4
National Institute of Advanced Industrial Science and Technology, Tsukuba 305-8568, Japan
5
Department of Engineering and Applied Sciences, Sophia University, Tokyo 102-8554, Japan
6
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan1

The incorporation of hydrogen into metals such as
steel is known to cause embrittlement of the metal. In aprevious study, vacancy clusters have been detected
near the hydrogen embrittlement fracture surface by
positron annihilation lifetime spectroscopy. However,conventional positron annihilation lifetime spectroscopy
requires measurements after hydrogen charging, andtherefore, in-situ positron annihilation lifetime
measurements were desired to understand defectbehavior during hydrogen charging. In this study, we
irradiated pure iron samples with high-energy pulsed
gamma-rays obtained from UVSOR and measured thepositron lifetimes in-situ during hydrogen embrittlement
tests or tensile tests using positrons induced inside thesamples.
Well-annealed pure iron tensile test pieces (10 mm
in width and 2 mm in thickness) were either (1)mounted in a 0.1 N NaOH aqueous solution containing
5 g/L NH4SCN and charged with cathodic hydrogenby applying a current density of 50 A/m2, or (2)mounted in a tensile testing apparatus and stretched toa nominal strain of 8% and held under a constant load.
The samples (1) and (2) were irradiated with a pulsed
gamma-ray beam for in-situ positron annihilation
lifetime measurements.
Figure 1 shows positron annihilation lifetime spectrum
obtained from a hydrogen-charged pure iron sample
mounted in NaOH aqueous solution. A lifetime
component of ~2 ns, corresponding to the annihilationof positrons in the aqueous solution, was observed with
non-negligible intensity, indicating that further
refinement of the measurement technique is needed.
Figure 2 shows positron annihilation lifetime spectra
obtained from a pure iron tensile-test piece under noload and under the load required for stretching to anominal strain of 8 %. The spectral shape clearly changed
by applying the load, indicating the appearance of adefect component. Furthermore, focusing on the change
in positron lifetime over time may reveal more thanwhat can be obtained by conventional positronannihilation lifetime spectroscopy. A more detailed
analysis of the obtained spectra is currently underway.

Ⅲ-2

Fig. 1. Positron annihilation lifetime spectrum obtained
from a hydrogen-charged pure iron sample mounted in
NaOH aqueous solution.

Fig. 2. Positron annihilation lifetime spectra obtained
from a pure iron tensile-test piece under no load (opensquares) and under the load required for stretching toa nominal strain of 8 % (open circles).

53 1 Ⅲ02-

BL6U Sciences
Ⅲ -2. Materials

BL6U

Momentum Microscope Study of a Kagome Superconductor CsV3Sb5
T. Kato1, K. Nakayama1,2, Y. Li3,4, Z. Wang3,4, Y. Yao3,4, F. Matsui5, T. Takahashi1,6,7
and T. Sato1,6,7

Department of Physics, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency(JST), Tokyo 102-0076, Japan
3
Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture andMeasurement (MOE), School of Physics, Beijing Institute of Technology, Beijing 100081, China
4
Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology,
Beijing 100081, China
5
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
6
Center for Spintronics Research Network, Tohoku University, Sendai 980-8577, Japan
7
Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, Sendai 980-8577, Japan
1

2

Ⅲ-2

The kagome lattice, consisting of a two-dimensional
network of corner-sharing triangles with 3d transition
metal ions, offers a fertile ground to explore exotic
quantum phenomena originating from electron
correlation and non-trivial band topology. Band
structure of a simple kagome lattice is composed of aflat band, a Dirac cone, and a saddle point. Owing tosuch a unique band structure, the kagome lattice shows
various interesting physical properties depending on theposition of the Fermi level (EF).
Recently, a new family of kagome metals AV3Sb5 (A =K, Rb, Cs) with a V kagome network has been discovered.
AV3Sb5 commonly exhibits superconductivity below Tc= 0.9-2.5 K and charge-density wave (CDW) below
TCDW = 78-103 K. To clarify the interplay amongsuperconductivity, CDW, and electronic states, we have
performed ARPES measurements of CsV3Sb5 (Tc = 2.5
K, TCDW = 91 K) by using momentum microscope at
BL6U in UVSOR [1].
Single crystals of CsV3Sb5 were synthesized withthe self-flux method. ARPES measurements were
performed using KREIOS 150 MM (SPECS) [2]. Theenergy resolution was set to be 35 meV.
Figure 1 shows the plot of ARPES intensity at EF as afunction of kx and ky at T = 120 K (above TCDW) measured
with 106-eV photons corresponding to the kz ~ 0 plane[3,4]. Photoelectrons in this wide momentum window
were simultaneously collected by using a momentum
microscope. One can recognize three types of Fermi
surfaces, a circular pocket and a large hexagonal
pocket centered at the Γ point and a small triangularpocket at the K point. The circular pocket at the Γ point
originates from an electron band with the Sb 5pz orbital.
On the other hand, the hexagonal pocket originatesfrom linearly dispersive bands with the dominant V
3dxz/yz orbital character. The triangular pocket at the K
point is associated with the Dirac-cone band with the
Dirac point at EB ~ 0.3 eV. This band is attributed to
the V 3dxy/x2-y2 orbital, and forms the saddle point
slightly above EF. Our high-resolution measurements
below TCDW (not shown) reveal the largest CDW-gap
opening on this saddle-point band. Therefore, thesaddle point plays a crucial role in stabilizing CDW in
AV3Sb5.

Fig. 1. ARPES-intensity map at EF plotted as a functionof kx and ky, measured at T = 120 K in CsV3Sb5. Red,
purple, and blue dashed lines are guides for the eyes totrace the experimental Fermi surfaces.

[1] T. Kato et al., submitted.
[2] F. Matsui et al., Jpn. J. Appl. Phys. 59 (2020) 067001.
[3] K. Nakayama et al., Phys. Rev. B 104 (2021) L161112.
[4] K. Nakayama et al., Phys. Rev. X 12 (2022) 011001.

54 2 Ⅲ02-

BL1U

Ⅲ -2. Materials Sciences

BL1U

Probing Vacancy-type Defects in Ce:LuAG Scintillators by GiPALS
Experiment and DFT Calculation
M. Kitaura 1, Y. Taira2,3 and S. Watanabe4

Faculty of Science, Yamagata University, Yamagata 990-8560, JapanUVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan3
School of Physical Sciences, The Graduate University for Advanced Studies, Okazaki 444-8585, Japan
4
Institute of Innovative Research, Tokyo Institute of Technology, Tokyo 152-8550, Japan1

2

existence of Al vacancies was suggested in Y3Al5O12(YAG) [3].

Intensity (count)

Positron annihilation lifetime spectroscopy (PALS) isa unique experimental technique that can visualize theexistence of vacancy-type defects in solids. Taira et al.,one of the authors, have developed gamma-ray induced
PALS (GiPALS) using ultrashort pulsed gamma-rays
generated by 90-degree inverse Thomson scattering [1].
We applied this method to the visualization of negatively
charged cation vacancies, which trigger the formationof photocarrier traps associated with defect complexesof cation antisites and oxygen vacancies in
Ce:Gd3Al2Ga3O12 (Ce:GAGG) crystals [2].
In the present study, GiPALS experiment has been
performed at 300 K for Ce-doped Lu3Al5O12 (Ce:LuAG)
crystals, which have the same crystal structure as
Ce:GAGG. GiPALS spectra were analyzed according to
the two-state trapping model of bulk and defect states.
The lifetimes and relative intensities were determinedby the least-square fitting using two exponential decayfunctions. Using these parameters, bulk- and defectlifetimes were calculated, and were compared to thoseobtained from the theoretical calculation based on twocomponent density functional theory (TC-DFT).
Figure 1 shows the GiPALS spectrum of a Ce:LuAG
crystals. The data were obtained at 300 K. The GiPALS
spectra are reproduced by the sum of two exponential
decay functions drawn by blue broken lines. The
positron annihilation lifetime becomes longer at thenegatively charged vacancy site, compared to the bulk
state free from vacancy-type defects. Therefore, theshort and long lifetime components are attributed to thepositron annihilation at the bulk and defect states,
respectively. The lifetimes i and relative intensities Ii
were analyzed by the least square fitting of experimental
data. The values of i and Ii are listed in Table I. The
bulk lifetime B and trapping rate  were estimated to be1662 ps and (1.530.07)109 s-1, respectively. Table IIlists bulk B and defect lifetimes 24c, 16a and 24d,
obtained by the present TC-DFT calculation. The
subscripts indicate the Wyckoff positions of the latticesites introducing cation monovacancies in the TC-DFT
calculation. The experimental value of B is almost
agreement with the calculated one. This result indicatesthe validity of our experiment and analysis.
In Table I, the value of 2 corresponds to the vacancyrelated lifetime. This value is similar to those of 24d, and16a in Table II. Thus, it is more likely that Al
monovacancies are introduced at 16a and 24d sites. The

10

5

10

4

10
10
10
10

Ⅲ-2

3

2

1

0

0

1
Time (ns)2

Fig. 1. GiPALS spectrum of a Ce:LuAG crystal
measued at room temperature. Broken lines indicate
the components due to positron annihilation at bulk
and vacancy-related defect sites. The sum of them also
was indicated by a red line.
Table I. Lifetimes i, and relative intensities Ii for
GiPALS spectra of Ce:LuAG, analyzed using the twostate trapping model.
I1 (%)
I2 (%)
1 (ps)2 (ps)
Ce:LuAG1321451.00.8

2261

49.00.8

Table II. Bulk B and defect lifetimes 24c, 16a and24d, obtained by the present TC-DFT calculation. The
subscripts indicate the Wyckoff positions of the latticesites introducing cation monovacancies in the TC-DFT
calculation.
B(ps)
24c(ps) 16a(ps) 24d(ps)Lifetimes

162

274

239

233

[1] Y. Taira et al., Rev. Sci. Instrum. 84 (2013) 053305.
[2] K. Fujimori et al., Appl. Phys. Express 13 (2020)
085505.
[3] F. A. Selim et al., Results Phys. 5 (2015) 28.

55 3 Ⅲ02-

BL1U Sciences
Ⅲ -2. Materials

BL1U

LCS-gamma Induced Positron Annihilation Study for the Dynamics ofDefect Behavior in Bulk Materials

Ⅲ-2

F. Hori1, S. Araki1, K. Sugita2 and Y. Taira2

Department of Quantum and Radiation Engineering, Osaka Prefecture University, Sakai 599-8531, Japan
2
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
apparatus for tensile test. Figure 2 shows the results ofpositron lifetime and voltage change after stressapplied. The initial drastic change in stress is due toelastic deformation at a moment of stress apply, andthe subsequent slow increase is thought to be due tothe introduction of dislocations and hardening due toplastic deformation. After applying stress, positron
lifetime increased slightly but almost constant. Thischange corresponds to defect formation such as
dislocations and vacancies. However, that change did
not exactly match the stress change. Considering thatthe positron lifetime analysis is an average value, it isnecessary to do multi component defects analysis on
the positron data.

Fig. 1. Newly developed stress applying positron
lifetime in-situ measurement apparatus at BL1U.

7000
6000
5000
4000
3000
2000
1000
0

Voltage (mV)The behavior of hydrogen atoms is attracting
attention in a wide range of research fields such as
high-strength structural materials and hydrogenstorage materials. In such materials, hydrogen atom
diffuses and has various interaction with defects andsurface, consequently it is possible to make change theserious characteristic features. In particular, in the
corrosion process of high-strength materials underhigh pressure and chemically harsh environment, thepresence or absence of defects in the material isconsidered to have a great influence on the intrusionof hydrogen and oxygen and the interaction withconstituent atoms in the material. It has been almost
impossible to directly observe the atomic-level defects
behavior that occurs inside the material during
processes such as corrosion. This has been hamperedby the need for high-energy acceleration of charged
particles such as electrons, which are probes in various
analytical methods used for detecting defects at theatomic level, and high-energy X-rays. On the other
hand, positron annihilation methods are used defects
research in materials powerfully. In normal defects
research, a radioisotope (RI) and an accelerated slow
positron beam are generally used for positronannihilation experiments. The maximum energy ofpositron emitted from most standard positron sourceof 22Na is about 540 keV and almost positron beam isthe order of 100 keV so that possible research area isnear surface of materials. In order to investigate thedynamics of the internal defect behavior which is notpossible to detect without destructing the material,mega electron volts accelerated fast positron is neededor positron production in target materials is useful. By
utilizing high-energy gamma rays generated byinjecting a laser beam from the outside into theelectrons of the UVSOR synchrotron radiation storage
ring, positron experiments for detecting defectbehavior in bulk materials such as the latter become
possible. We have developed positron annihilation
Doppler broadening system using LCS gamma-beam
at NewSUBARU synchrotron facility and successfullymeasured defects in bulk materials [1]. However, thatbeam line was closed at 2020. In this study, we havedeveloped a device of in-situ measurement of positronannihilation lifetime while applying stress to bulk asample at UVSOR beam line BL1U as shown in Fig.
1. In this system, initial stress is applied for the sample
and left as it was. Stress is measured as a voltage fromthe load cell connected to the sample.
Fe sample, which is well annealed at 1073 K for 1 h
to remove residual defects, was mounted on thisPositron annihilation lifetime (ps)

1

120
110
100

before applying stress

0

2

4

6
time (h)810Fig. 2. Stress and positron lifetime change as a functionof time.
[1] K. Sugita, S. Miyamoto, M. Terasawa, A. Iwase, K.
Umezawa and F. Hori, AIP Conf. Proc. 2182 (2019)040007.

56 4 Ⅲ02-

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Ⅲ -2. Materials Sciences

BL1U

Effect of the Particle Size on the Positron Annihilation Lifetime
and Relative Intensity of CeO2 Nanoparticles
S. Dohshi1, K. Maeda1, Y. Taira2, H. Toyokawa3 and T. Hirade4

Osaka Research Institute of Industrial Science and Technology, Izumi 594-1157, JapanUVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
3
National Institute of Advanced Industrial Science and Technology, Tsukuba 305-8568, Japan
4
Japan Atomic Energy Agency, Tokai 319-1195, Japan1

2

previously reported. Furthermore, as the particle size
decreases, the relative intensity of the longer lifetime
component (I2) of ca. 390 ps increases. The longer
lifetime component for CeO2 nanoparticles with aparticle size of 2.3 nm is found to be more than 90 %.
As particle size decreases, the ratio of surface to bulk
increases. The longer lifetime component of ca. 390 ps
observed in this experiment is dependent on theparticle size, suggesting the annihilation at the CeO2
surface. Theoretical calculations on the positronannihilation lifetime at CeO2 surface will be performedin the future.

Counts [arb. unit]

Recently, it has been reported that the presence ofoxygen vacancies in CeO2 catalysts affect theircatalytic activity such as automotive exhaust gas
purification, particulate matter and/or volatile organic
compound oxidation [1]. Therefore, it becomes more
and more important to analyze the presence and theconcentration of oxygen vacancies in CeO2 with highsensitivity.
Positron annihilation lifetime measurement is a
powerful tool for the detection of lattice defects such as
oxygen vacancies with high sensitivity. It was previously
reported that two lifetime components were observedfor CeO2 catalysts: shorter lifetime component of 170200 ps and longer lifetime component of ca. 400 ps [1].
Moreover, theoretical studies have estimated a positronannihilation lifetime of ca. 170 ps for the bulk of CeO2
without oxygen vacancies [2]. This lifetime is in good
agreement with the experimentally observed shorter
lifetime component. However, there is no theoreticalstudies about the longer lifetime component (ca. 400 ps),and various arguments such as annihilation in oxygen
vacancy clusters or at the surface have been
experimentally made about this lifetime component.
In this study, positron annihilation lifetimes of CeO2
catalysts with different primary particle sizes were
measured to discuss the longer lifetime component in
the positron annihilation for CeO2 catalysts.
The particle sizes, which calculated from XRD
analysis, of CeO2 nanoparticles used in this experimentwere 2.3 nm, 9.3 nm, 18.3 nm, and 26.7 nm, respectively.
We have set up a gamma-ray spectroscopy system at thelaser-Compton scattering (LCS) beamline of BL1U at
UVSOR-III [3], and measured the lifetime of theannihilation gamma-rays at room temperature using
BaF2 scintillation detector. We used the software
Lifetime9 (LT9) to analyze the spectra.
Figure 1 shows the positron annihilation lifetime
spectrum of CeO2 nanoparticle with a particle size of
2.3 nm. As shown in Fig. 1, this spectrum could be
fitted with two lifetime components; ca. 155 ps (τ1)
and ca. 390 ps (τ2). The positron annihilation lifetimes(τ1 and τ2) and relative intensities (I1 and I2; I2 = 100 –I1) analyzed using LT9 for CeO2 nanoparticles withdifferent particle sizes are listed in Table 1. Twolifetime components of ca. 170 ps and 390 ps wereobserved for all CeO2 nanoparticles. The shorter
lifetime component of ca. 170 ps is considered to beannihilation in the bulk of the CeO2 nanoparticles, as

10

4

10

2

10

0

0

1

2
Time [ns]34Fig. 1 Positron annihilation lifetime spectra of CeO2
nanoparticles with a particle size of 2.3 nm.
Table 1 Positron annihilation lifetime and relative
intensity of CeO2 with different particle size.
particle size
2.3 nm
9.3 nm18.3 nm26.7 nmτ1 [ps]155.0 ±17

τ2 [ps]388.2 ±1.5174.7 ±4.6176.7 ±7.8386.3 ±3.1
388.0 ±30

188.0 ±30408.0 ±21l2 [%]
93.5 ±0.785.1 ±5.966.3 ±1.153.6 ±4.0[1] X. Liu et al., J. Am. Chem. Soc. 131 (2009) 3140 .
[2] B. Barbiellini et al., Phys. Rev. Lett. 114 (2015)
147401.
[3] Y. Taira et al., Rev. Sci. Instr. 84 (2013) 053305.

57 5 Ⅲ02-

Ⅲ-2

BL2A Sciences
Ⅲ -2. Materials

BL2A

Mo LIII-Edge XANES Study of Highly Active MoCx Species in Mo-V
Modified H-MFI Catalysts for Methane Dehydroaromatization
K. Kuramochi1, R. Yamazaki1, Y. Sonobe3, Y, Uchimura2 and H. Aritani2,3Advanced Science Research Laboratory, Saitama Institute of Technology, Fukaya 369-0293 Japan
2
Graduate School of Engineering, Saitama Institute of Technology, Fukaya 369-0293 Japan
3
Faculty of Engineering, Saitama Institute of Technology, Fukaya 369-0293 Japan
Mo/V=40 (react. time.)
0 min.
5 min.
60 min.
105 in.
185 min.
-Mo2C (ref.)Mo metal (ref.)1.0

TEY (Normalized)

Ⅲ-2

For direct conversion from natural gases to usefulpetroleum compounds, innovative GTL (Gas To Liquid)catalysts are called for. A molybdenum- modified HMFI zeolite (Mo/H-MFI) catalyst is a typical MTB(Methane To Benzene; 6CH4 → C6H6 + 9H2) catalyst
with high activity for methane dehydroaromatization,
which is a noted GTL process. Over the Mo/H-MFI
catalysts, definite deactivation due to coke deposition
has been a serious problem for enhancement of MTB
reactivity, and thus, clarification of the deactivation
process over the catalysts is one of the important points.
A cause of the deactivation strongly depends on bothcoke deposition onto strong acid sites over H-MFI andstructural deactivation of carbonized Mo species. Oneof the most important subjects for catalytically highand durable activity is the elucidation of active Mocarbide sites. In this study, Mo LIII-edge XANES isapplied to characterize the active MoCx species on
Mo/H-MFI and Mo-V co-modified H-MFI.[1]Mo(5 wt%)/H-MFI (Si/Al2=23) and Mo-V/H-MFI(Mo/V=10-40) catalysts were prepared as describedin the previous paper.[2] The methane dehydroaromatization reactivity was evaluated at 1023 K. Mo
LIII-edge XANES spectra were obtained in BL2A of
UVSOR-IMS in a total-electron yield mode using InSb
double-crystal monochromator. A REX-2000 (Rigaku)
software was used for normalization of each XANES
spectra.
At Mo/V=40, maximum durability for catalytic MTB
reactivity was shown at 1023 K. For LIII-edge XANES
spectra over Mo-V/H-MFI catalysts as shown in Fig. 1,
deeply carbonized Mo species due to MoCx (x > 0.5) areformed. On the time course of the MTB reaction over
Mo-V/H-MFI (Mo/V=40), decrease of edge energy due
to rapid carburization of Mo ions is revealed in theinitial step. At 60 min., the catalytic MTB reactivity was
shown. After 105 min., the energy value relatively
approached the -Mo2C. Because deactivation of MTB
was shown after 60 min., the structural change due toformation of -Mo2C like species can be assigned thedecrease of active MoCx sites. The rate of deactivation
reduced by V co-modification, and thus, inhibition ofexcess carbonization by V co-modification is proposed.
The result is likely to relate to a suppression effect ofdeactivation. For stabilize the active MoCx species, V
co-modification is effective on Mo/H-MFI catalysts.

0.5

0.0
2520

2525
2530
Energy / eV

2535

Mo-V/H-MFI(23)V-free
Mo/V=40
Mo/V=10
-Mo2C (ref.)Mo metal (ref.)1.0

TEY (Normalized)

1

0.5

0.0
2520

2525
2530
Energy / eV

2535

Fig. 1. Mo LIII-edge XANES spectra of Mo-V/H-MFI(Si/Al2=23) [top] and the Mo/V=40 on the time courseof MTB reaction [bottom] at 1023 K. The references,
-Mo2C and Mo metal, are also shown in each figure.
Table 1. Edge energy values obtained by 1stderivatives of LIII-edge XANES (shown in Fig. 1).
Mo-V/H-MFI (React. 185 min.) Mo-V/H-MFI (Mo/V=40)
Catalyst

V-free
Mo/V=10
Mo/V=40
 -Mo2C
Mo Metal

Edge Energy/ eV2520.92520.72520.92521.02520.2Time onEdge Energy
Stream / min.
/ eV

0
5
60
105
185

2522.02520.72520.62520.92520.9[1] H. Aritani et al., UVSOR Activity Report 2020 48(2021) 57.; H. Aritani et al., UVSOR Activity Report2019 47 (2020) 50.
[2] H. Aritani et al., J. Environm. Sci. 21 (2009) 736.

58 6 Ⅲ02-

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Ⅲ -2. Materials Sciences

BL2A

Evaluation of the Electronic State of MgO by NEXAFS Spectroscopy
E. Kobayashi1, K. K. Okudaira2, S. Yoshioka3 and A. Inoishi4

Kyushu Synchrotron Light Research Center, Tosu 841-0005, Japan
2
Chiba University, Chiba 263-8522, Japan
3
Graduate School of Engineering, Kyushu University, Fukuoka 819-0395 Japan
4
Institute for Materials Chemistry and Engineering, Kyushu University, Kasuga 816-8580, Japan
1

Magnesium oxide (MgO) is used in various fields
such as catalysts, electrical insulator and heat-resistantmaterials. In the development of organic solar cells,
the introduction of a metal oxide layer improved
functionality and efficiency [1]. For example, an MgO
nanolayer is used as the electrode [1-3]. Therefore, it
is important to evaluate the electronic state of the
produced metal oxide.
We have been studying using Near-edge X-ray
absorption fine structure (NEXAFS) spectroscopy as amethod for evaluating electronic states. Usually, thespectrum is carried out by the electron yield (EY)
method and the fluorescence yield (FY) method. The
EY method is a surface-sensitive method, and the FY
method is a bulk-sensitive method.
In this paper, we investigated how the presence of
defects changes the electronic states of the metal oxidesurface and bulk.
The sample is MgO powder. Samples with defects
were prepared by mechanically crushing. NEXAFS
spectra of the MgO powders were measured at thebeamline 2A of the UVSOR in the Institute of
Molecular Science. For TEY, the drain current fromthe sample was measured. For PFY fluorescence Xrays were collected using an energy dispersible silicon
drift detector (SDD). All experiments were performedat room temperature.
Figure 1 shows the Mg K-edge NEXAFS spectra of
MgO powder obtained from TEY. The black line is theuntreated sample and the red line is the defective
sample. The overall shape of the NEXAFS spectrum
is very similar. The inset is an enlargement of the risingedge of the spectrum. The rise of the spectrum of
defect MgO shifted to the low energy side. This is dueto the presence of reduced MgO.
Figure 2 shows the Mg K-edge NEXAFS spectra of
MgO powder obtained from PFY. The black line is theuntreated sample and the red line is the defective
sample. The overall shape of the NEXAFS spectrum
is very similar, but distorted by defects. The risingedge of the spectrum is shifted to the low energy side
due to the defect, but it is smaller than that obtained by
TEY.
The NEXAFS results obtained by the TEY method
showed little difference between the untreated andcrashed samples. On the other hand, the NEXAFS
results obtained by the PFY method differed significantly.
Since the mechanical crashing was done in theatmosphere, the defects formed on the surface arechemically unstable and quenched. On the other hand,the defects inside the powder are retained.

Ⅲ-2

Fig. 1. Mg K-edge NEXAFS spectra of MgO byusing TEY.

Fig. 2. Mg K-edge NEXAFS spectra of MgO byusing PFY.

[1] H. J. Bolink, H. Brine, E. Coronado, and M.
Sessolo, J. Mater. Chem. 20 (2010) 4047.
[2] J. Ma, G. Yang, M. Qin, X. Zheng, H. Lei, C. Chen,
Z. Chen, Y. Guo, H. Han, X. Zhao, and G. Fang, Adv.
Sci. 4 (2017) 1700031.
[3] I. Ierides, I. Squires, G. Lucarelli, T. M. Brown,
and F. Cacialli, J. Mater. Chem. C 9 (2021) 3901.

59 7 Ⅲ02-

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Ⅲ -2. Materials

BL2A

Sintering Behavior of Mg-Doped Hydroxyapatite Nano Particles
H. Murata, R. Kawanabe and A. Nakahira

Department of Materials Science, Osaka Prefecture University, Sakai 599-8531, Japan

Ⅲ-2

Hydroxyapatite (HAp) is a main inorganic componentof human bones and teeth. It has good biocompatibility
and thus it is used as materials for artificial bones andteeth. HAp in human bodies is not pure but contains
various kinds of impurities. They affect properties of
HAp such as solubility in water, mechanical strengthand so on.
Artificial HAp was commercially available in various
forms, powders, granules, pastes and sintered bodies.
Doping into HAp have been attempted to control
properties of HAp. However, some dopants induce Ca
deficiency [1], which cause high-temperature instability.
In this study, local environment of Mg in hydroxyapatitewere investigated by X-ray absorption near edge
structure (XANES) to reveal their effects to sintering.
Mg-doped HAp (Mg-HAp) samples were preparedby the solution-precipitation method. Starting materials
were 0.10 mol/L of Ca(NO3)2 and (NH4)2HPO4 aqueous
solutions. The initial Ca/P molar ratio were set to 2.0,
which is larger than that of stoichiometric HAp, toprevent formation of Ca vacancies. The (NH4)2HPO4
aqueous solution was dropped into the Ca(NO3)2
aqueous solution under Ar atmosphere. Then, thesolution was sealed in a PFA bottle and it was matured
at 37 °C in a water bath for 72 h. After maturing,
samples were washed by ion-exchanged water, filtrated
and dried at 50 °C. A parts of samples were pressed into
pellets and sintered at 1000 °C for 6 h.
Samples were characterized by powder X-ray
diffraction (XRD), inductively coupled plasma opticalemission spectrometry (ICP-OES) and XANES. MgK XANES were collected at BL2A in UVSOR by thepartial fluorescence yield method using a silicon drift
detector. [2] Samples were mounted on a metal plateusing carbon tapes.
The XRD pattern of as-dried samples can be assigned
to that of hydroxyapatite. Although stoichiometric HAp
were obtained in the present condition, (Ca+Mg)/P
molar ratio of Mg-doped samples was smaller than thatof HAp, 1.67. This indicated that Mg2+ in HAp are also
associated with Ca vacancies and excess H [1].
Figure 1 shows Mg-K XANES of the samples. The
spectrum of the sintered Mg-HAp has different featuresfrom that of as-dried Mg-HAp. The peak A and C showsformation of MgO. The shoulder D can be assigned to
Mg-doped β-TCP. Therefore, Present Mg-HAp werepartially decomposed to MgO and β-TCP during
sintering. Since non-stoichiometric HAp are partiallydecomposed to CaO or β-TCP at 1000 °C [3], the low(Ca+Mg)/P molar ratio of the samples also cause thedecomposition. Therefore, Mg-HAp and CaCO3 weremixed to compensate lack of (Ca+Mg)/P molar ratio

and they were sintered. However, its Mg-K XANES
spectrum has the same features to that of MgO. This
result means Mg2+ are ejected from HAp during sintering.
High-temperature instability of Mg-HAp are not due tolow (Ca+Mg)/P molar ratio but fundamental character.

Fig. 1. Mg-K XANES of (a) as-dried and (b) sintered
Mg-HAp and (c) Sintered samples of mixture MgHAp and CaCO3, respectively. Spectra of MgO andMg-doped β-TCP were also shown as references.

[1] K. Matsunaga et al., Acta Biomater. 6 (2010) 2289.
[2] H. Murata, T. Taniguchi and T. Yamamoto, UVSOR
Activity Report 2013 41 (2014) 56.
[3] K. Shitara et al., J. Asian Ceram. Soc. 2 (2014) 64.

60 8 Ⅲ02-

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Ⅲ -2. Materials Sciences

BL2A

Local Structure around Mg in Mg1-xNixAl2O4
S. Yoshioka 1, K. Yasuda1, S. Matsumura1, E. Kobayashi2 and K. Okudaira3

Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Fukuoka 819-0395, Japan
2
Kyushu Synchrotron Light Research Center, Tosu 841-0005, Japan
3
Graduate school of Advanced Integration Science, Chiba University, Chiba 263-8522, Japan

Spinel oxides with the general formula AB2O4 can beformed with various kinds of divalent A and trivalent B
cations. Owing to their unique mechanical, electronic,
and magnetic properties, the spinel oxides have gained
considerable attention not only from the fundamental
research fields but also from the industrial application
point of view. Some spinel compounds accommodate alarge degree of cationic disorder. The cationic disordering
naturally affects the structural properties of the spinels.
For example, magnesium aluminate (MgAl2O4) andnickel aluminate (NiAl2O4) spinels are generally known
as normal and inverse spinel structures, respectively.
However, their inversion degrees for synthetic specimens
were also reported to be fluctuating between 0 and 1,
respectively, due to the cationic disordering. Recently,
the structure of Mg1-xNixAl2O4 was reported using
neutron total scattering to understand the cationicdisordering process [1]. X-ray absorption spectroscopy(XAS) is a powerful structure characterization methodthat uses an X-ray probe to reveal local atomic
coordination and electronic structures. In this study, we
focus on the local structures in MgAl2O4–NiAl2O4 solid
solutions, particularly cationic-disordered structures.
The polycrystalline samples of Mg1-xNixAl2O4 (x =0.0, 0.05, 0.2, 0.5, 0.8, 1.0) were synthesized by a solidstate reaction. They were sintered in air at 1300 ºC for
10 h followed by furnace. Mg and Al K-edge XANES
measurements were performed on BL2A beamline at
UVSOR Synchrotron Facility, Okazaki, Japan, using
the partial fluorescence yield method. A KTiOPO4
double-crystal monochromator gives Mg and Al Kabsorption edges in the energy regions 1290–1340 eV
and 1540–1610 eV, respectively. The measurements of
Mg and Al K-edge XANES spectra were carried out invacuum at a pressure and temperature of 1×104 Pa and
20 ºC, respectively. Fluorescence X-rays of Mg Kα andAl Kα were collected utilizing an energy-dispersible
silicon drift detector.
The Mg K-edge XANES spectra for Mg1-xNixAl2O4
are shown in Fig. 1 with the composition values x = 0,0.05, 0.2, 0.5, and 0.8. The intensity of each spectrum
was normalized to a value of 1 at the photon energy of1335 eV after the removal of the background intensity.
All the Mg K-edge XANESs show similar spectra andno significant energy shifts or relative intensity changes
at the major peaks are observed. It suggests that the local
structure of Mg remains unchanged for the whole
composition range of Mg1–xNixAl2O4, whereas the Mg
concentration changes with respect to x.

Mg K-edge

x=0.80Intensity (arb. units)1

x=0.50x=0.20x=0.05

MgAl2O4

1300

1310

1320

1330

Photon energy (eV)Fig. 1. Mg K-edge XANES spectra of Mg1-xNixAl2O4.

[1] E. O’Quinn et al., J. Am. Chem. Soc. 139 (2017)
10395.

61 9 Ⅲ02-

Ⅲ-2

BL2A Sciences
Ⅲ -2. Materials

BL2A

Local Structure Investigations of Zn in ZnAl2O4 Induced on Swift Heavy
Ion Irradiations
S. Yoshioka1, K. Yasuda1, S. Matsumura1, E. Kobayashi2 and K. Okudaira3

Department of Applied Quantum Physics and Nuclear Engineering Kyushu University, Fukuoka 819-0395, Japan
2
Kyushu Synchrotron Light Research Center (SAGA-LS), Tosu 841-0005, Japan
3
Graduate School of Advanced Integration Science, Chiba University, Chiba 263-8522, Japan

Ⅲ-2

Zinc aluminate oxide (ZnAl2O4) is one of thecommon spinel compounds. Since it shows a variety
of interesting physical and chemical properties, its
microstructure has been extensively investigated. A
cationic disordered ZnAl2O4 spinel is represented by
the formula of [Zn1–xAlx](ZnxAl2–x)O4, where thesquare brackets and the parentheses denote thetetrahedral and octahedral sites, respectively. The
variable x is called the inversion parameter, whichquantifies the cation disorder. Radiation with swift
heavy ions (SHIs) interacts with materials and causes
the structural change. It is therefore applied to material
processing, modifications, etc. SHI irradiation provides
high energy deposition through electronic stopping to
the materials. SHIs in insulating solid materials are
known to leave trails of damage along the ion pathwith a diameter of several nanometers. Structuralchange related to the cationic disorder has been also
observed in ZnAl2O4 with SHI irradiation usingtransmission electron microscopy observation. In thisstudy, we clarify local coordination of each cation
element, on which we conducted synchrotron radiationbased X-ray analysis.
Sintered ZnAl2O4 samples with the shape of 10 × 4 ×
0.5 mm were used in this study. These specimens were
irradiated with 340 MeV Au ions to fluences of 1 × 1012
cm-2 at the H1 beamline of the tandem ion accelerator
facility in the Japan Atomic Energy Agency (JAEA)Tokai. At the beginning of each paragraph, two spacecharacters should be inserted as an indent. Zn L2,3-edge
and Al K-edge XANES measurements were performedat the BL2A beamline of UVSOR Okazaki, Japan, using
the partial fluorescence yield method (PFY). A
Be3Al2Si6O18 (beryl) double-crystal monochromatorgives Zn L3-edge in energy regions 1000 -1070 eV. In
the cases of Al K-absorption edges, a KTiOPO4 doublecrystal monochromator scanned the energy region
1540–1610 eV. The samples were set with their surface
perpendicular to the incident X-ray beam. Fluorescence
X-rays of Zn Lα and Al Kα were collected using anenergy dispersible silicon drift detector (SDD). All
measurements of XANES spectra were carried out invacuum of 1 × 10–5 Pa at room temperature.
The XANES spectra with the Zn L3-edge are shownin Fig. 1 for the ZnAl2O4 samples before and after
irradiation with 340 MeV Au ions at fluences ranging
from 1 × 1011 to 1 × 1012 cm−2. The intensities of spectra
were normalized to a value of 1 at 1055 eV for Zn L3edge, after the removal of background intensities. As

shown in Fig. 1, Zn L3-edge XANES of the pristine
ZnAl2O4 sample shows fine structures such as peaks A
to H. The Zn L3-edge XANES of the ZnAl2O4 samples
have not changed drastically from that of the pristine
sample even with high fluence irradiation. However, theintensities at the peak B were decreased and spectral
shape between the peaks F and G as indicated an arrow
were slightly changed with increasing of the ion
fluences.

ZnAl2O4
1×1012 cm-2

Intensity (arb. units)

1

1×1011 cm-2

I
B

CD E

F

GH
pristine

A

1020

1030

1040

1050

Photon energy (eV)Fig. 1. Zn L3-edge XANES spectra of pristine andirradiated ZnAl2O4 with 340 MeV Au ions to fluencesof 1×1012 cm-2.

62 10 Ⅲ02-

BL2B

Ⅲ -2. Materials Sciences

BL2B

UPS Spectroscopy of TFP Doped P3HT/PCBM Thin Films
K. K. Okudaira and Y. Hoshi

Chiba University, Chiba 263-8522, Japan

Valence top region

Cutoff region
Intensity (arb. units)

(b)

(a)

TFP 7wt%
TFP 5wt%
TFP 0wt%

24

23.5

2

1

0

Binding energy (relative to EF) (eV)Fig. 1. UPS of secondary electron cutoff (a) andvalence top (b) region at hν = 28 eV for P3HT/PCBM
thin film with various TFP doping level.

TFP 5%

Intensity (arb. units)

Organic solar cells (OSC) based on blends ofpolymers and fullerence derivatives are promising
candidates for new renewable resource. However, thepower conversion efficiency of OSC is low forcommercial use. A bulk hetero-junction structurecomposed of poly (3-hexylthiophene (P3HT) anddphenyl-C61 -butyric-acid-methyl ester (PCBM)
showed an improvement of the efficiency. To achieve
higher efficiency, it is necessary to improve the excition/
charge transport. Recently, it was reported that byincorporating additives (i.e. doping) such as
tetrafluorophthalnitrile (TFP), P3HT/PCBM system
obtain high conversion efficiency [1]. In this study weobserved photon- energy dependent photoemission of
TFP doped P3HT/PCBM thin film to estimate thechange of the electronic structure.
Photoemission measurements were performed at thebeam line BL2B of the UVSOR storage ring at theInstitute for Molecular Science. Incident photon
energies of 28 eV 40 eV, and 90 eV were used. Incident
angle of photon and take-off angle of photoelectron are
60° and 0° with respect to surface normal, respectively.
At first RR-P3HT (Mn ~ 40000) was dissolved with
0.1wt% in chlorobenzene, followed PCBM adding
with weight ratio of 1:0.9 to P3HT. TFP with 5 wt%
and 7 wt% were then added to the P3HT/PCBM
solution, followed by stirring for 30 min. at 50 °C. The
solution consisting of P3HT/PCBM with or without
TFP was spin-cast on the cleaned ITO substrate.
Figures 1 (a) and (b) show the measured UPS spectraof the secondary electron cutoff and valence top region,
respectively. By TFP doping valence band top is shifted
to Ef about 0.2 eV. It is expected that the gap statesdevelop due to polaron and/or bipolaron onpolythiophene chains of P3HT by TFP doping [2].
Figure 2 shows the measured UPS spectra at hν = 28 eV,
40 eV and 90 eV. In the UPS at hν = 90eV, the relative
intensity of the peak at binding energy (EB) of 6.5 eV islarger than those at hν = 40 eV and 28 eV. By considering
the photoionization cross-section of S 3p and C 2s and2p [3], the peak at EB of 6.5 eV can be assigned to theπ state included S 3p orbital in thiophene ring. The
photon-energy dependent photoemission can provide
the precise information on the electronic structure.

hv=90eV

hv=40eV

hv=28eV

15

10

5

0

Binding energy (relative to EF) (eV)Fig. 2. photon-energy dependent photoemission of
P3HT/PCBM thin film with 5 wt% TFP doping level.

[1] S. Jeong et al., J. Nanosci. Nanotechnol. 14 (2014)9219.
[2] M. Lögdlund et al., Phys. Rev. Lett. 23 (1989) 1841.
[3] J.–J. YEH, Atomic Calculation of Photoionization
Cross-sections and Asymmetry Parameters, (Gordon
and Breach Science Publishers) (1993).

63 11 Ⅲ02-

Ⅲ-2

BL2B,Sciences
BL7U
Ⅲ -2. Materials

BL2B, BL7U

Valence and In-gap states of a Polyethylene Model Oligomer, C44H90, Film
Studied by Conventional and High-Sensitivity Photoelectron Spectroscopy
1

Ⅲ-2

R. Nakazawa1, M. Yoshizawa1, S. Kera2 and H. Ishii1,3,4

Graduate School of Science and Engineering, Chiba University, Chiba 263-8522, Japan
2
Institute for Molecular Science, Okazaki 444-8585, Japan,
3
CFS, Chiba University, Chiba 263-8522, Japan
4
MCRC, Chiba University, Chiba 263-8522, JapanThe electronic structures of materials are a key tounderstand and control the nature of materials. Not only
their highest occupied molecular orbital (HOMO) but
also weak density-of-states (DOS) in the energy gap has
been focused to discuss the practical electric properties.
Our research group has been developing high-sensitivity
photoelectron spectroscopy (HS-UPS) which enables todirectly probe such in-gap states of organic materials[1,2]. Recently, we have applied constant final state
photoelectron yield spectroscopy (CFS-YS) to organicand inorganic materials, and a very weak in-gap states
whose density is less than 10-6 of HOMO [3]. The
observed in-gap states are believed to be in relation todefect and disorder of the films. However, the origin of
in-gap states is still open question. To qualify the natureof the wave function of the in-gap states, photoelectron
spectroscopy using synchrotron radiation (SR) is suited
because of photon energy tenability and polarizabilityof light, although conventional SR light includes strayphotons to increase background intensity, leading to low
sensitivity. BL7U has a unique advantage that highsensitivity measurement is enable for less than 10 eV
photon energy. We can expect that photon energy
dependence and angular dependence of photo electron
could give a hint to identify the wave function of in-gap
states. In this study, a model compound of polyethylene,
tetratetarcontane (TTC, C44H90) was investigated toclarify the valence and in-gap states by using BL2B
(conventional UPS), BL7U(HS-UPS), and CFS-YS at
Chiba University. Polyethylene is a basic polymer andapplied to various products mainly as insulator. It is alsointeresting in relation to triboelectricity. The clarificationof in-gap states is useful to understand its insulating
nature.
TTC film was prepared by vacuum vapor deposition
on an ITO-coated glass substrate, and the film thickness
was 20 nm. The CFS-YS measurement was performed
at Chiba University. SR measurements were performed
at BL2B and 7U at UVSOR.
Figure 1 shows the UPS of TTC films for hν=120
eV@BL2B and 21.2 eV@Chiba U. The horizontal axis
is the ionization energy relative to the vacuum level.
The onset in 21.2 eV spectrum locates around 9 eV,
which is consistent with the reported value of 8.9 eV [4].
The onset region is enhanced for 120 eV spectrum
because of hν dependence of photo- ionization crosssection of the HOMO, giving the onset around 7.5 eV,
consistent with our CFS-YS results in the inset of Fig.
1. This result suggests that the reported ionizationenergy should be updated.
Figure 2 shows the results of HS-UPS at BL7U for
TTC film with and without anneal. The valence top
region in the figure exhibited the intensity difference.
Blue spectrum gives more intensity than red one,suggesting that the in-gap states seems to be reduced bydecreasing the degree of disorder due to annealing. The
obtained spectrum is compared with our CFS-YS result
as shown in the inset. The both spectra are very similar,
demonstrating the feasibility of high-sensitivity
measurement at BL7U. The angular dependence ofthe photoelectrons from the in-gap states (1 to 3 eV in
the binding energy in Fig. 2) were isotropic. Now weare going to check the photon energy dependence tosqueeze the information about the wave function natureof the in-gap states.

Fig. 1. UPS spectra of the TTC film for hν= 21.2 and120 eV. The inset shows CFS-YS curve (black dots).

Fig. 2 HS-UPS spectra of TTC film with and without
anneal. (The inset: CFS-YS result)[1] F. Bussolotti, J. Elect. Spec. Relat. Phenom. 204(2015) 29.
[2] T. Sato et al., Appl. Phys. Express 10 (2016) 011602.
[3] R. Nakazawa et al., Appl Phys Express 14 (2021)
071004.
[4] K. Seki et al., Chem. Phys. 105 (1986) 247.

64
III 02- 12 -BL3U

Ⅲ -2. Materials Sciences

BL3U

Structure Analysis on Helical Nanofilament of B4 Phase of Bent-core
Liquid Crystals Mixed with Rod-like Cholesteric Liquid Crystals by
Resonant Soft X-ray Scattering (RSoXS) at UVSOR
Y. Takanishi1, F. Araoka2 and H. Iwayama3,4Faculty of Science, Kyoto University, Kyoto, 606-8502, JapanRIKEN Center for Emergent Matter Science, Wako 351-0198, Japan
3
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
4
School of Physical Sciences, The Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan1

2

Due to the new intermolecular interactions, frustrationand competition, soft matter is expected to have a new
structure and new functionality. Liquid crystal istypical one of soft matter, and it exhibits various mesophases due to such an effect. For example, bent-coremolecules show unique liquid crystalline phases called
B1~B8. The B4 phase was the lowest temperaturephase observed in the bent-core liquid crystals, and it
shows spontaneously chiral separated domains despiteof achiral molecules. After various experimental
results, it is found that this phase forms a nano-helicalstructure.
Recently one of authors (YT) studied the binary
system between a rod-like cholesteric liquid crystal(CLC) mixture and a bent-core liquid crystal showing
a B4 phase [1]. The structure of the binary systemcomposed of rod-like cholesteric liquid crystal
mixture and bent-core molecules was analyzed inorder to confirm whether nano-scale phase separation
as observed in the 5CB – P-8OPIMB binary system isformed. As a summary, a new smectic structure that
does not appear in only constituent molecules withwide temperature range was unexpectedly discovered.
This structure seems to be fundamentally composed ofrich concentration of rod-like molecules. On the other
hand, there remains an open question with respect tothe effect of the nano-helical filament of B4 phaseformed by the bent-core liquid crystal.
In resonant X-ray scattering, using X-ray whoseenergy is coincident with a certain atom absorption
edge, the structure factor becomes a tensor instead of
the scalar in conventional X-ray diffraction. Recently,
carbon K-edge resonant scattering has been applied to
study, and successful in obtaining the precise
structures of polymer blends, block copolymer, andliquid crystals. In this study, we report the local nanostructure analysis of B4 nano-helical filament using
resonant soft-X-ray scattering (RSoXS) technique.
Concentration dependence of rod-like molecules andtemperature dependence were measured, and themixing effect on the helicity and correlation of B4
nano-helical filament are discussed.
The experiment was performed at BL3U of UVSOR.
For the measurement, a new vacuum chamber for small
angle measurement was fabricated. Used achiral bentcore liquid crystal was P-8OPIMB, and a rod-likecholesteric liquid crystal (CLC) mixture was composedof a nematic mixture (ZLI-2293, Merck) doped with achiral rod molecule (MLC-6248, Merck). Samples usedwere filled in the isotropic phase between two pieces of
100 nm-thick Si3N4 membranes (NTT-AT). The
scattering was detected by CCD (ANDOR DO940PBN). Incident X-ray beam was tuned between 270~300
eV. Typical RSoXS image was shown in Fig.1, and in
this compound, carbon K-edge energy was 285.5 eV.
Figure 2(a) shows chirality concentration dependenceof helical half pitch of B4 phase. By mixing CLC
mixture, half pitch of nano-helical filament decreases
from ca.120 nm to ca.80 nm, but pitch is independent ofchirality. Figure 2(b) shows correlation length as afunction of chirality concentration of CLC. Correlation
length of mixtures is about three times longer than thatof pure P-8OPIMB, and slightly increases withincreasing the chiral dopant concentration. It suggeststhat helical pitch of the nano filament of bent-coremolecules rich region is spatially homogeneous due tothe influence of the rod-like molecule rich region.

Fig. 1. Typical 2D RSoXS image from the helicalnano-filament of the B4 phase.
(a)

(b)

Fig. 2. half pitch (a) and its correlation length (b) as afunction of chiral dopant concentration.

[1] Y. Takanishi, Soft Matter 17 (2021) 563.

65
III 02- 13 -Ⅲ-2

BL3B Sciences
Ⅲ -2. Materials

BL3B

Evaluation of Fluorescence Lifetimes of Wavelength Shifting Fibers
for High-energy Particle Experiments
K. Shintate, R. Abe, R. Ishiyama, T. Naitou, S. Nakamura, S. Sakano, J. Ohashi, Y. Tajima
and H. Y. Yoshida
Department of Physics, Yamagata University, Yamagata 990-8560, Japan

Ⅲ-2

Recently, operation of particle detectors at higher
counting rates has been required in a high-energy
physics experiment. To satisfy this requirement,
scintillators used in particle detectors need to have ashort fluorescence lifetime to allow fast time response.
For this purpose, we measured fluorescence spectra anddecay curves of newly developed wavelength shifting
fibers for the future project of neutral kaon rare decay
experiment [1]. The fluorescence decay curves were
measured by using light pulses from visible to near
ultraviolet under single bunch operation, which enables
a time-correlated single-photon counting.
Figure 1 shows the decay curve of a wavelength
shifting fiber Y-11 for the 500 nm band under excitation
at 424 nm at room temperature. The blue lines indicate
experimental data. The lifetime was analyzed by using
the data analysis framework ROOT [2].
We assumed that the obtained decay curves are
fitted with the formuladata. The fluorescence lifetimes of Y-11, YS4 and YS6,
determined from our analyses, are summarized in Table
1.

Fig. 1. Decay curve of Y-11 measured at room
temperature under excitation at 424 nm obtained forthe 500 nm photoluminescence band.

�𝐼𝐼�𝑡𝑡� � � 𝑃𝑃�𝑡𝑡 � �𝜃𝜃�𝑡𝑡 � � 𝑇𝑇� �𝐺𝐺�𝑡𝑡 � 𝑡𝑡 � � 𝑑𝑑𝑑𝑑 � ,

where

and

��

�

𝑡𝑡
𝑃𝑃�𝑡𝑡� � � 𝐴𝐴� exp �� �,
𝜏𝜏�
���

�

(� � 1, 2, 3 and 𝐴𝐴� � 1)

𝐺𝐺�𝑡𝑡 � 𝑡𝑡 � � � � �� exp ������𝑡𝑡 � 𝑡𝑡 � � �� ��
�.
2𝜎𝜎��

(� � 1, 2)𝐼𝐼�𝑡𝑡� represents the observed decay curve, and 𝑃𝑃�𝑡𝑡�
represents the true fluorescence decay curve. If the true
decay curve is composed of multiple components, it isdescribed as the linear combination of exponential
decay functions with the parameters of lifetime 𝜏𝜏� andinitial intensity 𝐴𝐴� . 𝜃𝜃�𝑡𝑡 � � 𝑇𝑇� � is a step function todecide the time origin 𝑇𝑇� . 𝐺𝐺�𝑡𝑡 � 𝑡𝑡 � � represents theresolution of the measurement system, the time
structure of the beam, and so on, and is given by a single
gaussian or a sum of two gaussians. The red line is thefitting curve which reproduce the experimental data.
The lifetime analyses of wavelength shifting fiber
YS4 and YS6 [3] were carried out by using the same
analysis method. The top of Fig. 2 shows the decay
curve of YS4 for the 500 nm band under excitation at
416 nm. The fitting curve reproduce the experimental

Fig. 2. Decay curves of YS4 (top) and YS6 (bottom)
measured at room temperature under excitation at 416
nm and 418 nm. The former and latter are obtained forthe 500 and 492 nm photoluminescence band.
Table 1. Fluorescence lifetimes of Y-11, YS4 and YS6,
determined from data analyses.
SampleλEX [nm]λEM [nm]τ [ns] (Ratio)

Y-11

424

500

6.44±0.00

YS4

416

500

1.37±0.00

YS6

418

492

1.27±0.00[1] J. Comfort et al., Proposal for 𝐾𝐾� → 𝜋𝜋 � 𝜈𝜈𝜈𝜈̅
Experiment at J-PARC (2006).
[2] R. Brun and F. Rademakers, Nucl. Instrum. Methods
Phys. Res. A389 (1997) 81.
[3] H. Nakamura et al., Europhys. Lett. 95 (2011) 22001.

66
III 02- 14 -BL3B

Ⅲ -2. Materials Sciences

BL3B

Thermoluminescence of LuAG Thick Film Scintillators Prepared via
Chemical Vapor Deposition Process
S. Matsumoto1, S. Kurosawa2,3 and A. Ito1

Graduate School of Environmental and Information Sciences, Yokohama National University,
Yokohama, 240-8501, Japan
2
Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan3
New Industry Creation Hatchery Center (NICHe), Sendai 980-8579, Japan1

Scintillators are phosphor materials with conversion
ability from radiation such as X-rays, γ-rays, and αparticles into UV–visible photons [1]. Scintillators
have been used as radiation imaging systems coupledwith photon detectors such as position-sensitive CCD.
Recently, radiation imaging systems have been used infields including non-destructive testing, nuclear
medical imaging, and geological surveying [2–4].
Scintillator screens with excellent luminescence andemission wavelengths compatible with photon
detectors are required for radiation imaging. Tl+ doped
CsI films and Tb3+ -doped Gd2O2S (GOS) powder
phosphors are used as scintillator screens because of
their high luminescence yield and well-matchedemission band (500–800 nm) with CCD detectors [5].
Columnar and pixelated scintillators have beenutilized to improve light yield and spatial resolution.
Furthermore, thin scintillator screens of 10 μm or lesscan prevent light dispersion and are expected to be
used in microtomography techniques [6].
Lu3Al5O12 (LuAG)-based scintillator shows a highstopping power for radiation, excellent light yield, anda fast scintillation decay. Because of the excellent
hardness of LuAG, LuAG thick film with less than 10µm was hardly obtained via mechanical polishing.
Crystal growth from the vapor phase is a promisingprocess for the preparation of LuAG thick films.
However, the vapor-grown LuAG thick film was only
reported using the pulse laser deposition method, theresultant film was only 140 nm. In the previous work,
we have demonstrated the preparation of 5 µm-thickCe3+:LuAG films via a chemical vapor deposition
process at a high deposition rate [7]. The thick film
showed an excellent light yield and a fast decay timecompared with the Ce3+:LuAG grown single-crystal
by the melting-growth process. The reason for these
excellent scintillation properties is not well known.
Defect information is useful to explain the variation in
scintillation properties of crystals grown by different
methods. In this report, we have demonstrated thethermoluminescence (TL) properties for the sake ofobtaining the defects in the vapor-grown Ce3+:LuAG
thick film.
In BL3B of UVSOR facilities, we measured TL
properties from 18 K to 300 K (room temperature) for
vapor-grown Ce3+:LuAG film and melting-grownCe3+:LuAG single crystal. The crystals were irradiatedat 165 nm for 10 minutes at a low temperature of 14–18

K. After the irradiation, the sample temperature wasslowly raised and luminescence intensity was measured
the with a CCD detector.
The TL emission spectrum for the Ce3+:LuAG thickfilm at 220 K was similar to that for the Ce3+:LuAG
single crystal at 140 K as shown in Fig. 1 (a). Theseemission peaks were originating from 5d–4f transitionof Ce3+ ions. The TL glow curves of the thick film andsingle crystal are shown in Fig. 1 (b). The curve for the
single crystal had continuous emissions up to room
temperature while one peak was found at 140–150 K.
In contrast, the thick film had two bands at ~80 and
220 K in the curve. These TL results suggested thattypes and amounts of defects existed in the single
crystal scintillator were more and larger than those in
the film scintillator.

Fig. 1. (a) TL spectra and (b) glow curve of LuAG
thick film and LuAG single crystal.
[1] C.W.E. van Eijk, Phys. Med. Biol. 47 (2002) R85.
[2] D.R. Schaart et al., Phys. Med. Biol. 54 (2009) 3501.
[3] J. Glodo et al., Phys. Procedia. 90 (2017) 285.
[4] S. Yamamoto et al., Radiat. Meas. 115 (2018) 13.
[5] T. Yanagida et al., Radiat. Meas. 55 (2013) 99.
[6] T. Martin et al., J. Synch. Radiat. 13 (2006) 180.
[7] S. Matsumoto, A. Minamino, A. Ito, Sens. Mater. 33(2021) 2209.

67
III 02- 15 -Ⅲ-2

BL3B Sciences
Ⅲ -2. Materials

BL3B

Temperature Dependence of Photoluminescence Properties of Li2HfI6
2

Ⅲ-2

C. Fujiwara1, S. Kurosawa1,2 and A. Yamaji1

Insititute for Materials Research, Tohoku University, Sendai 980-8577, JapanNew Industry Creation Hatchery Center, Tohoku University, Sendai 980-8579, Japan1

We have developed Cs2HfI6 (CHI) scintillator [1]for radiation monitoring in the Fukushima Daiichi
Nuclear Power Plant. CHI has an emission wavelengthof approximately 700 nm and light yield of 60,000
photons/MeV. Such a red emitting scintillator can be
attached to an optical fiber for use in remote radiation
monitoring [2]. However, CHI has low neutron
sensitivity, and neutron muttering is also required due
to nuclear debris including [3].
Most conventional neutron scintillators have anemission wavelength of 500 nm or less, and thesescintillation materials are not suitable for the remotemonitoring system with the optical fiber. We havedeveloped a neutron scintillator with red and infraredemission by replacing Cs in CHI with Li. Here, 6Li hasa large neutron capture cross section. In this study, wemeasured the temperature dependence of the luminescence
properties to estimate the band gap energy (Egap) andto discuss the luminescence mechanism.
A Li2HfI6 crystal specimen was synthesized by thevertical Bridgman growth method in our laboratory
using 99.9 %-pure LiI powders and 99 %-pure HfI4
powders. We measured the photoluminescence excitationand emission spectra at 15, 50, 100, 150, 200, 250, 300
and 350 K. Multi-Gaussian fit was operated on theobtained spectra to analyze emission bands.
Figure 1 show the photoluminescence excitationand emission spectra of Li2HfI6. At 15K, Li2HfI6 hadan emission band of ~660 nm. The photoluminescenceband stably existed from 15 K to 50 K. This emission
bands can be originating from charge transfer emission
or self-trapped exciton.
On the Other hands, Li2HfI6 had two emission bands
from 100 K to 250 K. The one band located at ~550 nm
was observed excited by ~305-nm photons. The otherband had the broad red emission peak at ~660 nm. At
The emission intensity of such bands gradually decreased
as temperature increase. No luminescence was observedat room temperature due to thermal quenching.
To determine the emission mechanism exactly, wemeasure the temperature dependence of decay time in
the future.

Fig. 1. Temperature dependence of photo-luminescence
spectra of Li2HfI6.

[1] S. Kodama, S. Kurosawa et al., Journal of Crystal
Growth, 492 (2018) 1.
[2] https://fukushima.jaea.go.jp/en/pamphlet/topics/
pdf/topics-fukushima070e.pdf.
[3] https://www.hitachi-hgne.co.jp/download/2017/2017news17_17-11-1a.pdf

68
III 02- 16 -BL3B

Ⅲ -2. Materials Sciences

BL3B

Reflectivity Spectra of Sm0.9Ca0.1S in Vacuum Ultra Violet Region
Y. Yokoyama1, K. Kishida1, F. Matsunaga1, M. Kanou1, K. Takano1, Y. Okamoto1,
H. S. Suzuki2, K. Takehana3, Y. Imanaka3 and K. Takenaka1
Department of Applied Physics, Nagoya University, Nagoya 464-8603, JapanThe Institute of Solid State Physics, The University of Tokyo, Kashiwa 277-8581, Japan
3
National Institute for Materials Science (NIMS), Tsukuba 305-0003, Japan1

2

spectrum of Sm0.9Ca0.1S also demonstrated an
appearance of the reflectivity dip around 40 meV,strongly suggesting further insulation by the Ca
doping. On the other hand, for the reflectivity spectrain the higher energy region (Fig. 2(b)), problems in thedata consistency remain. The reflectivity data above 5
eV must be reconsidered for precise discussion on thechanges in the electric state due to the Ca doping,whereas fine structures below 5 eV are reliable. To
elucidate the changes in the electronic states by thevalence transition induced by the electric field, it isnecessary to construct a measuring system that thereflectivity spectra in the wide energy region can becollected at the liquid nitrogen temperature and underthe electric field in the future.

 ( cm)

5

104
103
102
101
100
10-1
10-2
10

Sm1-xCaxS
0.10
x=0
0

100

200

300

400

Temperature (K)Fig. 1. Electrical resistivity of Sm1-xCaxS single crystals.

(b) 0.4

1
0.8
0.6
0.4
0.2
0

Sm1-xCaxS
x=0

295 K

0.10
0.01

0.1

1

Photon Energy (eV)

Reflectivity(a)Reflectivity

Samarium monosulfide (SmS), in which twoelectronic configurations (insulator (4f)6 and metal(4f)5(5d)1) of Sm energetically compete, is known asvalence fluctuation materials. The electronic state of
Sm undergoes the transition to (4f)5(5d)1 from the (4f)6state by applying pressure and chemical doping, while
the (4f)6 state is stable under ordinary pressure andtemperature condition [1]. It is promising to be applied
to materials for negative thermal expansion (NTE) andactuators by controlling these electronic states [2]since this phenomenon is accompanied by a large
volume change up to 10 %. To study changes in theelectronic states due to the valence transition, we
conducted systematic optical reflectivity measurementsof Sm1-xYxS single crystalline samples, covering wide
energy and compositional region [3]. It is clarified thata characteristic structure, which showed the changes
in electronic states induced by the valence transition,
became appeared in the optical spectra at Ycomposition of 0.28 [3]. For the application of theelectric-field-driven actuator, the changes in theelectronic state during the valence transition inducedby the application of the electric field must be studied.
It is also necessary that SmS can be applied electricfield enough to induce the valence transition.
In this work, we prepared a Sm0.9Ca0.1S singlecrystalline sample to enhance the insulation, andconducted the optical reflectivity spectral measurements
at room temperature at no electric field first. Normal
incident reflectivity spectra were collected at 295 K byusing a Fourier-type interferometer (0.005–1.6 eV)
and a grating spectrometer (1–3 eV) installed with amicroscope. For the measurements from visible to thevacuum-UV region (2–30 eV), we used synchrotron
radiation at BL3B of UVSOR, Institute for Molecular
Science.
Figure 1 shows the electrical resistivity of Sm0.9Ca0.1S
single crystal. By comparing to the non-doped SmS, it
is clearly shown that the electrical resistivity
significantly increased by more than two orders ofmagnitude. We succeeded in the valence transition to
the metallic phase of this sample by applying theelectric field of 300 V/cm at the liquid nitrogentemperature (data not shown). The optical reflectivity
spectra of Sm0.9Ca0.1S are shown in Fig. 2. The spectrain the lower energy region (Fig. 2(a)) show that both
Ca-doped and non-doped SmS are characteristic of theinsulator, in terms of low reflectivity in the far-IR
region except for phonon peak. The reflectivity

Sm1-xCaxS

0.3

295 K

0.2
0.1
0

0.10
0

5

x=0

10 15 20 25 30

Photon Energy (eV)Fig. 2. Optical reflectivity spectra of Sm1-xCaxS at 295
K: (a) from far-IR to visible and (b) from visible tovacuum-UV regions.

[1] A. Jayaraman et al., Phys. Rev. B 11 (1975) 2783.
[2] K. Takenaka et al., Sci. Rep. 9 (2019) 122.
[3] Y. Yokoyama et al., Phys. Rev. B 100 (2019) 245143.

69
III 02- 17 -Ⅲ-2

BL3B Sciences
Ⅲ -2. Materials

BL3B

Optical Investigation on Fluoro-olefins in VacuumUltraviolet for New Refrigerant Gas Development
K. Yamanoi1,2, Y. Sakata1, H. Iwayama3, Y. Hasumoto1,2, O. Yamamoto1,2 and M. Noumi1,2
Osaka university, Suita 565-0871, JapanDAIKIN Industries Ltd, Settsu 566-8585, Japan
3
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
1

2

Ⅲ-2

Chlorofluorocarbon (CFC), hydrochlorofluorocarbon (HCFC), and hydrofluorocarbon (HFC) havebeen used as a refrigerant. These gases have high global
warming potential (GWP) over 100. Recently, thehydrofluoroolefin (HFO) gases are expected as new low
environmental load refrigerant due to its low GWPs
since olefin gas is unstable and easily decompose by
ultraviolet light in nature. In order to put HFO into
practical use as a refrigerant, it is necessary to clarify thephysical characteristics of HFO such as UV absorption
and decomposition process. In this study, we measured
the vacuum ultraviolet (VUV) light induced
decomposition of HFO.
The decomposition spectra measurements werecarried out in BL3B in UVSOR facility. Trans-C2H2F2
gas was flowed into vacuum chamber through thecapillary tube. The pressure in vacuum chamber was
kept less than 3×10-4 Pa. The VUV light from 8 to 30
eV was irradiated on sample gas and the ionizedmolecular fragments were detected TOF-mass
spectrometer shown in Fig. 1.
Figure 2 shows the decomposition spectra ofC2H2F2. We could clearly observe the ionizationenergies of each fragments. The decomposition fromC2H2F2 to CH2F2 and HF arise with 14.9 eV. Withhigher energy about 18 eV, the C2H2F2 dissociate to
CHF and CHF. From our previous results, the transC2H2F2 has the absorption from 135 nm (9.2 eV) to190
nm (6.5 eV) as shown in Fig. 3. The absorption at 145
nm is attributed to the stretching and twisting ofcarbon double band and the 190 nm is the transition
from π to π* in C=C bonds, respectively [1]. However
the ionization and decomposition threshold is quite
higher than these absorption. These results show thatthe higher photon energy over 14 eV is needed fortrans-C2H2F2 to be decomposed in the air. However,
we notice that other components exist such as oxygenand nitrogen which react with fluorocarbon in real case.
In conclusion, we could observe the opticalproperties and ionization energy of decomposition
process of C2H2F2 in VUV region. The results let us
know the UV- or VUV-induced decomposition
dynamics of fluoro-olefins as refrigerant in nextgeneration.

nozzleelectron detector

Beam

ion detector

Fig. 1. Schematic image of the experimental setup in
BL3B.

Fig. 2. Decomposition spectra of trans-C2H2F2.

Fig. 3 Absorption spectrum of C2H2F2.

[1] G. Belange et al., J. Chem. Phy 55 (1971) 2055.

70
III 02- 18 -BL3B

Ⅲ -2. Materials Sciences

BL3B

Absorption Bands of Tl+ Centers in CsI-based Ternary Crystals
S. Ito and T. Kawai

Graduate School of science, Osaka Prefecture University, Sakai 599-8531, Japanabsorption bands in CsI:Tl+ may be related to thecoordination states around the Tl+ ion.

300

280

Wavelength (nm)
260
240

220

10 K
CsI:Tl +Ⅲ-2
Optical Density (arb. unbits)

The optical properties of the Tl+ centers in alkali
halide crystals have been extensively investigated [1].
The Tl+ centers in alkali halide crystals with the NaCltype crystal structure exhibit the typical A, B, and C
absorption bands. On the other hand, the Tl+ centers incesium halide crystals with the CsCl-type crystal
structure have absorption bands different from thetypical A, B, and C bands; in particular, the appearanceof absorption bands in CsI:Tl+ is unusual [2,3]. It has
been regarded that the unusual absorption spectra of
the Tl+ centers in cesium halide crystals originate fromthe different ionic configurations around the Tl+ ion in
the NaCl- and CsCl-type crystal structures [2]. To
provide a better understanding of these observations,
we investigated absorption bands of CsCaI3:Tl+,
CsBa2I5:Tl+, Cs4CaI6:Tl+, and Cs4SrI6:Tl+ crystals, whichwere prepared by a cell method [4].
Figure 1 shows the absorption spectra of CsCaI3:Tl+,
CsBa2I5:Tl+, Cs4CaI6:Tl+, and Cs4SrI6:Tl+ crystals at 10
K. For reference, the absorption spectrum of CsI:Tl+ is
also demonstrated in the top of Fig. 1. In CsCaI3:Tl+, theabsorption bands having no extremely different
absorption intensity are observed at 4.54, 5.14, and 5.55
eV. A absorption band is observed at 4.32 eV for
CsBa2I5:Tl+. In Cs4CaI6:Tl+ and Cs4SrI6:Tl+, theabsorption band with a doublet structure is observed atabout 4.23 eV and the band with the largest absorption
intensity is observed at 4.94 eV. In addition, the weakabsorption bands are observed at about 5.18 and 5.33 eV.
The 4.23 eV band with a doublet structure and the 4.94
eV band in Cs4CaI6:Tl+ and Cs4SrI6:Tl+ may be assigned
to the A and C bands of the Tl+ centers, respectively,from the intensity ratio between them. On the other
hand, it is hard to assign the absorption bands of
CsCaI3:Tl+ and CsBa2I5:Tl+ to the A, B, and C bands,
just like the absorption bands in CsI:Tl+.
The CsI-based ternary crystals above have various
crystal structures; orthorhombic (CsCaI3) [5], monoclinic(CsBa2I5) [6], and trigonal (Cs4CaI6 and Cs4SrI6) [7]structures. In the host lattice, the Tl+ ions which replace
the Cs+ ion, have various coordinations of the I− ions.
That is to say, the Tl+ ions in the ternary iodide crystals
have different coordination of the I− ions from the Tl+
ion in the CsI crystal. Despite the difference of thecoordination, the absorption bands of CsI:Tl+ seem toappear at the energy positions which the absorption
bands of the Tl+ centers in the ternary iodides areobserved. For example, the lowest absorption band of
CsI:Tl+ is located at 4.27 eV, which is close to the lowest
bands of Cs4CaI6:Tl+ and Cs4SrI6:Tl+ in the energy
position. The 4.52 eV absorption band of CsI:Tl+ is
located at the energy position close to the lowest 4.54
eV band of CsCaI3:Tl+. The energy positions of the

CsCaI3:Tl+

CsBa2I5:Tl+

Cs4CaI6:Tl

Cs4SrI6:Tl
4.0

4.5

+

+

5.0
Photon Energy (eV)5.5

Fig. 1. Absorption spectra of CsI:Tl+, CsCaI3:Tl+,
CsBa2I5:Tl+, Cs4CaI6:Tl+, and Cs4SrI6:Tl+ crystals at
10 K.

[1] P. W. M. Jacobs, J. Phys. Chem. Solids 52 (1991)
35.
[2] S. Masunaga and M. Ishiguro, J. Phys. Soc. Jpn. 25(1968) 1337.
[3] T. Kawai, et al., Phys. Status Solidi B 227 (2001)
587.
[4] S. Hashimoto and M. Itoh, Jpn. J. Appl. Phys. 27(1988) 726.
[5] J. Grimm, et al., Inog. Chem. 45 (2006) 10905.
[6] B. Kang, et al., J. Phys. D: Appl. Phys. 49 (2016)
395103.
[7] L. Stand, et al., J. Cryst. Growth 486 (2018) 162.

71
III 02- 19 -

BL3B Sciences
Ⅲ -2. Materials

BL3B

Photoluminescence Properties of Cs2ZrI6
2

Ⅲ-2

S. Kodama1 and S. Kurosawa2

Saitama University, Saitama 338-8570, JapanNew Industry Creation Hatchery Center, Tohoku University, Sendai 980-8579, Japan1

The intrinsic luminescent scintillators with thechemical formula of A2BX6 (A: monovalent cation, B:
tetravalent cation, X: halogen ion) are attracting large
attention due to their high light outputs and highenergy resolutions. We reported Cs2HfI6 and Rb2HfI6
as the novel red-emitting scintillators with the highlight output over 40,000 photons/MeV [1-5]. Whilethe candidate compositions of A2BX6 scintillators areactively studied, the detailed mechanism of intrinsic
luminescence is still unclear. We have studied thephotoluminescence properties of A2BX6 scintillators tounderstand the basic luminescence behaviors andcompare them with the that of conventional phosphorsusing the beamline of BL3B, UVSOR.
In the UVSOR activity report 2020, we reported the
low-temperature photoluminescence properties of
Cs2HfI6. Cs2HfI6 showed two photoluminescence bands
at 10K. The origin of each band was unclear. In order tocompare the effect of B cation on the photoluminescence
properties, we grew Cs2ZrI6 crystal and evaluated thetemperature dependence of photoluminescence emission
spectra. A single crystalline Cs2ZrI6 specimen was
obtained by the vertical Bridgman growth method in ourlaboratory from 99.95 %-pure ZrI4 and 99.999 %-pure
CsI powders.
Figure 1 shows the measured spectra of Cs2ZrI6. The
emission wavelength of Cs2ZrI6 was ~630 nm at 300 K,
and shifted towards shorter wavelength as cooled downreaching ~720 nm at 10K. Cs2ZrI6 had only one
photoluminescence band at all temperature, while
Cs2HfI6 had two bands at 10K. Therefore, the numbersof photoluminescence bands of Cs2BI6 were determined
to be two when B is Hf and to be one when B is Zr. The
tetravalent cation B might play the important roll in theluminescence phenomena of A2BX6 scintillators. For
future study, we would continue to study A2BX6
compounds to reveal the rolls of A, B and X ions.

[1] S. Kodama et al., IEEE Trans. Nucl. Sci. 67 (2020)
1055.
[2] S. Kodama et al., Appl. Phys. Express 13 (2020)
047002.
[3] S. Kodama et al., UVSOR Activity Report 2019 47(2020) 60.
[4] S. Kodama et al., UVSOR Activity Report 2020 48(2021) 65.
[5] S. Kodama et al., Rad. Meas. 124 (2019) 54.

Fig. 1. Temperature dependence of photoluminescence
excitation and emission spectra of Cs2ZrI6 at 10, 50,
100, 150, 200, 250, 300 and 350 K.

72
III 02- 20 -BL4U

Ⅲ -2. Materials Sciences

BL4U

Structural Analysis of Unvulcanized Rubber by Scanning Transmission Xray Microscopy
T. Ohigashi1,2,3, F. Kaneko4, H. Yuzawa1 and H. Kishimoto4

UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
Institute of Material Structure Science, High Energy Accelerator Research Organization, Tsukuba 305-0801, Japan3
School of Physical Sciences, The Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan
4
Sumitomo Rubber Industries Ltd., Kobe 651-0071, Japan
1

2

Reduction of consumption of limited resources is
nowadays a critical issue to maintain our daily life.
Rubber is one of the important resources and its demandis assumed to increase especially according to growth ofcar industries. Therefore, further improvement in wearand destruction-resistant of rubber is necessary to
reduce its consumption. Then, control of crosslinking of
sulfur in rubber is a key technology. Heterogeneity of
network of crosslinking in rubber has been confirmedby small-angle neutron scattering [1]. This heterogeneity
causes destruction of rubber because it gathers internal
stress under deformation. Therefore, dispersion of acrosslinking reagent in the rubber is important to makethe crosslinking network homogeneous.
To achieve the above goal, it is important to measure
the relationship between the dispersion and various
parameters of synthesis. Thus, this dispersion has been
conventionally tried to depict by using electron
microscopy. However, its observation was not easy
because the rubber contains only small amount of thecrosslinking agent. Moreover, the crosslinking agent is
consisted of light elements and is easily damaged byelectron beam. Then, scanning transmission X-ray
microscopy (STXM) can be an alternative approach.
STXM can probe the crosslinking agent by using nearedge X-ray absorption fine structure (NEXAFS). The
advantages of STXM are high spatial resolution
around 30 nm and much lower radiation damage thanthe electron microscopy. In this report, the distributionof crosslinking agent in unvulcanized rubber isinvestigated by STXM.
An ultra-thin section of the unvulcanized rubber of
250 nm thick was prepared as a sample by a cryo ultramicrotome. In the case of STXM observation, thesample was cooled down to ~ -90 degree with cryocooling setup to suppress the radiation damage [2].
Figure 1(a) shows an X-ray fluorescence image at
N-K line by using transmission electron microscopy
with an energy dispersive detector. Since signal
intensity of N-K line is low, the image is noisy anddoes not have any structures. Even though thedetection of the X-ray fluorescence brings highsensitivity to the analytical system, the crosslinking
agent could not be detected. We assumed that thecrosslinking agent was damaged by irradiation of theelectron beam.
The STXM image acquired at the X-ray energy of
401 eV is shown in Fig. 1(b). The observed image

shows many dark domains with high absorption. X-ray
absorption spectra of these dark domains (Fig. 2(a))
are compared with references of the crosslinking agent“A” and “B” by comparing with the reference spectra(Fig. 2(b)). Matrix of the rubber has quite lower
nitrogen signals than the dark domains, which implies
heterogeneity of the distribution of the crosslinking
agent. As a result of linear combination fitting, thesedark domains are consisted of the crosslinking agent“A” and “B”.
(a)

(b)

2 µm

5 µm

Fig. 1. (a) Images of unvulcanized rubber acquired bytransmission electron microscopy with an energy
dispersive detector acquired at N-K line and (b) thatby STXM at N-K edge (401 eV).
(a)

(b)

Fig. 2. (a) X-ray absorption spectra of the unvulcanizedrubber in the dark domain (solid line) and matrix(dashed line) in Fig.1(b) around N-K edge and (b)those of the crosslinking agents for “A” (solid line)and “B” (dashed line).

[1] Y. Ikeda, N. Higashitani, K. Hijikata, Y. Kokubo
and Y. Morita, Macromolecules 42 (2009) 2741.
[2] T. Ohigashi, F. Kaneko, Y. Inagaki, T. Yano, H.
Kishimoto and N. Kosugi, UVSOR Activity Report2017 45 (2018) 34.

73
III 02- 21 -Ⅲ-2

BL4U Sciences
Ⅲ -2. Materials

BL4U

C-K Edge Spectra of Bound-rubber Structure in SBR Materials
with Filler and/or Reagents
T. Ejima1, 2 and Y. Tamura2, 3, *SRIS, Tohoku University Sendai 980-8577, JapanIMRAM, Tohoku University, Sendai 980-8577, Japan3
JSR Corporation, Yokkaichi 510-8552, Japan
1

2

Ⅲ-2

Adding filler materials such as carbon black toelastomer materials such as synthetic rubber cansignificantly change mechanical properties: stressproperties, tensile strength, and abrasion resistance [1].
The factors that cause the changes in mechanicalproperties are not well understood, and the type andthe amount of filler materials added to obtain thedesired mechanical properties are known empirically.
In addition, it is known that the structure of anelastomer material differs at each scale and exhibits ahierarchical structure [2-4]. Among the hierarchicalstructure, we presume that the chemical state and the
3D structure of the bound-rubber structure formed
between filler particles at the nm scale determine theoverall mechanical properties. In the study, we will
add filler materials and/or reagents to elastomer
materials that the mechanical properties are known,
then the chemical states of the bound rubber structure
and its spatial distribution will be measured using the
STXM in BL4U. We believe that this process will
clarify the origin of the mechanical properties.
In the measurement, compounds were prepared froman elastomer material with a filler material and various
reagents, and styrene-butadiene rubber (SBR) andmodified SBR are used as the elastomer materials. The
fabricated compounds were cut into sections and usedin the STXM measurements. The measurement was
performed with a spatial resolution of 100 nm and an
exposure time of 2 msec per point. The obtained soft Xray images clearly distinguish the position of the added
filler material. Based on the preliminary NEXAFS
results, spectral measurements were performed focusing
on the difference between the π*- and the σ*- structuresof the C-K absorption edge. The obtained nanoscopic
spectra around bound-rubber structures in a same
compound showed a similar spectral shape with achange in peak intensity depending on the presence or
the absence of the filler and/or reagents. Different spectral
shape was observed around a bound-rubber structure
according to a modification of the SBR. An example ofthe spectral change in shape is shown in Fig. 1. By theenergy positions of the peaks, we estimate the origins ofpeaks as that: peak A is a transition from C1s orbital toπ* orbital due to the C=C bond, peak B is a transition to
C-H* orbital, and peaks C and C' are transitions to σ*
orbital [5].

Fig. 1. C-K edge spectra of SBR and modified SBR
with same filler and reagents. Curves are smoothing
results for guide to see.

[1] M. Ashida et al., J.Soc. Rubber Science andTechnology, Japan 49 (1976) 821.
[2] K. Nakajima, et al., Rub. Chem. Technol. 90 (2017)272.
[3] J. Kikuma, et al., J. Surf. Anal. 25, (2018) 34.
[4] Z. Martin, I. Jimenez, M.A. Gomez-Fatou, M. West
and A. P. Hitchcock, Macromolecules 44 (2011) 2179.
[5]J. Stoehr, "NEXAFS Spectroscopy", Springer- Verlag,
Berin Heiderberg GmbH (1992), Chap. 7 and 8.

*Present Address: ENEOS Materials Corporation,
Yokkaichi, Mie 510-0871, Japan74
III 02- 22 -BL4U

Ⅲ -2. Materials Sciences

BL4U

Analysis of Materials for Secondary Batteries by STXM
E. Hosono1,2,3, D. Asakura1,2,3, H. Yuzawa4 and T. Ohigashi4,5Global Zero Emission Research Center, National Institute of Advanced Industrial Science (AIST),
Tsukuba 305-8569, Japan
2
Research Institute for Energy Conservation, AIST, Tsukuba 305-8565, Japan
3
AIST-UTokyo Advanced Operando Measurement Technology Open Innovation Laboratory (Operando-OIL),
Kashiwa 277-8565, Japan
4
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
5
School of Physical Sciences, The Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan
1

In order to improve the performance of secondary
batteries such as lithium-ion batteries (LIB) anddevelop innovative electrode materials, investigationon the electronic state of electrode materials undercharge/discharge condition is required. This is because
the electronic state determined by redox conditions is
one of the critical factors for the energy density suchas charge/discharge capacity and operating voltage ofbattery. Since soft X-ray absorption spectroscopy(XAS) is sensitive to the change of local electronic
state, it is suitable analytical method for electrodematerials [1,2].
In addition, study of facet is also important tocontrol of the stability of the interface between theelectrode active material and the electrolyte. To
elucidate the behavior of the facet, analysis for spatial
distribution of electronic state at interface is required.
For spatially selective analysis, various techniquesof electron microscopes have been developed. For
example, TEM-EELS and TEM-EDS are widely used
as elemental analysis with a high spatial resolution.
However, in order to understand the electronic state of
the active materials, synchrotron radiation soft X-ray
spectroscopy is advantageous in terms of the energy
resolution and lower beam (X-ray) damage than thedamage by electron beams in electron microscopes.
Moreover, the scanning transmission soft X-ray
microscopy (STXM) with a spatial resolution ofseveral tens of nm is highly effective for analyzing theelectronic-state distribution in one particle of theelectrode material because the particle size is in theorder of several micrometers.
So far, we have mainly focused on cathode materials
like transition-metal oxides, but now we apply STXM
analysis to 2D carbon materials used for the anode as
well. Figure 1 shows the STXM image of 2D carbon
nanosheets at 320 eV and the C K-edge XAS spectrumof selected area. Graphite-like π* and σ* peaks areobserved. We believe that STXM is important for
carbon materials as well because it enables analysis forthe distribution of local electronic structure to discuss
the stability of the material.

Ⅲ-2

Fig. 1. STXM image and spectrum of selected area.

[1] Y. Nanba et al., Chem. Mater. 28 (2016) 1058.
[2] D. Asakura et. al., ChemPhysChem. 17 (2016)
4110.

75 23 Ⅲ02-

BL4U Sciences
Ⅲ -2. Materials

BL4U

Probing the Electronic Structure of Ni-Co Binary Oxide/Graphene
Nanocomposites as Supercapacitor Electrodes by Scanning Transmission
X-ray Microscope
H. W. Chang1,2, T. C. Huang2, T. Ohigashi3, C. H. Chuang1, Y. C. Tsai4, C. L. Dong1 and W. F. Pong1
Department of Physics, Tamkang University, Tamsui 251, Taiwan
Department of Chemical Engineering, National United University, Miaoli 360302, Taiwan
3
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
4
Department of Chemical Engineering, National Chung Hsing University, Taichung 40227, Taiwan
1

2

Ⅲ-2

Nickel and cobalt-based oxide are considered aspromising materials for supercapacitors owing to themultiple oxidation states and excellent electrochemical
redox activity. The conductive carbon materials (such asgraphite, carbon nanotubes, and graphene) serve as aconductive component can created the possibility toform the conducting interconnection between carbon
materials and transition metal oxides, allowing fast ionsand electrons transport inside interior space of transition
metal oxide pore/channel structure, thus dramaticallyenhanced the electrocatalytic activity. In this study, Ni-Co
binary oxide were synthesized on the graphene to obtain
Ni-Co binary oxide/graphene (NCG) nanocomposites as
supercapacitor electrodes. NCG nanocomposites were
tested with the applied voltage of 0.3 and -0.1 V toevaluate pseudocapacitive behavior toward studying thechange of the local chemical environment of a selected
element using STXM. Figure 1 show the optical density
images, STXM stack mapping, and XANES spectra of
NCG at C K-edge and O K-edge under applied voltage
of 0.3V and -0.1V. The C K-edge XANES spectra has
several distinct features (Ga, Gb, and Gc). Features Ga
and Gc at 284.6 and 290.9−291.9 eV are associated withthe transitions from C 1s to the unoccupied π* and σ*
orbitals, respectively, reflecting the bonding perpendicular
to the ring plane and within the ring plane. Features Gb
consist of three peaks Gb1 (286.3 eV), Gb2 (287.5 eV),and Gb3 (288.5 eV) correspond to C−O π* (hydroxyl or
ether), C=O π* (carbonyl groups), and O=C−O π*(anhydride, lactone, or carboxylic acids). The O K-edge
XANES spectra reveals Ha and Hb features at 532.8 and
540.0−545.0 eV. These features are associated with
C=O π* states of carbonyl groups and the O−H σ*, C−O
σ* and C=O σ* symmetry states from carbonyl,
carboxylic acid, and hydroxyl groups. The spectral
profile in Figs. 1(g) and (h) changes with the bias
potential applied from selected regions of the edges(yellow) and the center (red) that indicate favorable
structural and chemical reversibility during the charge/
discharge process, suggesting that the oxygen-containing
functional groups provide pseudocapacitance throughFaradaic reactions that occur near the surface of thegraphene-based materials: >C−OH ↔ C=O + H+ + e−,− COOH ↔ − COO + H+ + e−, and >C=O + e− ↔
>C−O− [1-3]. Further studies at Ni and Co L-edge are
expected to provide detail information of the energy
storage mechanisms.

Fig. 1. Optical density images of NCG under (a) 0.3
V and (d) -0.1 V. (b,e) C K-edge and (c,f) O K-edge
STXM. (g) C K- and (h) O K-edge STXM-XANES ofNCG from different regions (yellow and red).

[1] Han et al., Nat. Commun. 11 (2020) 1.
[2] Gandhiraman et al., J. Phys. Chem. C 118 (2014)
18706.
[3] Chang et al., J. Phys. Chem. C 120 (2016) 22.

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BL4B

Development of Reflection XMCD Measurement Setup for the Investigationof Inner Structures of Magnetic Thin Films at UVSOR BL4B
K. Yamamoto, H. Iwayama, O. Ishiyama and T. Yokoyama
Institute for Molecular Science, Okazaki 444-8585, Japan

Magnetic thin films/multilayers with complex depth
structures exhibit a wide variety of magnetic
phenomena due to the interactions between layers [1].
Furthermore, multilayer structures have been used torealize useful properties in recording media, which isan important application of magnetic materials. Direct
observation of the magnetic distribution in the depth
direction of such magnetic multilayers has been used
to elucidate the mechanism of evolution of magnetic
structures in thin films
We installed an experimental setup for reflectance xray magnetic circular dichroism (XMCD) method [2] inthe soft X-ray region at BL4B and experiments were
performed on test samples as shown in Fig. 1.
The sample and the detector can be rotatedindependently to obtain reflectivity. X-rays were detectedby a photodiode (AXUV100G, Optodiode inc.). The
magnetic field was about 0.35T, and measurements
were made at room temperature. The magnetic field wasapplied by two pairs of Nd magnets disposed oppositely.
The magnets can be rotated and the relative positional
relationship between the magnetic field and the sample
was kept constant. The setup is schematically depicted
in Fig. 2.
We used off-axis components of x-rays from thebending magnet to obtain circularly polarized light. The
x-rays are elliptically polarized. XMCD intensity wasmeasured by changing the direction of magnetic field.
The sample was CoFeB and an oscillating structure
was observed due to the interference of the cap layer
and the underlying layers. We observed the difference
corresponding to XMCD by changing the direction ofmagnetic field, which is consistent with the simulation
results. The same measurements were made around theabsorption edges and spectroscopic information was
extracted. These results can be reproduced by thesimulation based on the full matrix algorithm and themagnetooptical effects of the elliptically polarized xrays were treated explicitly. Although there have beenprevious studies using XMCD of reflectance, there arefew studies that extends this method to obtain
spectroscopic information. We also conducted
spectroscopic measurements and obtained photon
energy and reflection angle dependence to analyze thedepth-resolved magnetization information.

Ⅲ-2

Fig. 1. The experimental setup installed at BL4B.

Magnetic
thin films
X-rays2θ

θ
PhotodiodeFig. 2 The illustration for the XMCD reflectivity
measurements.

[1] F. Hellman et al., Rev. Mod. Phys. 89 (2017)025006.
[2]S. Macke and E. Goering, J. Phys. Condens. Matter.
26 (2014) 363201.

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Dirac Fermions and Topological Phase Transition in XMg2Bi2 (X = Ba and Sr)
D. Takane1, Y. Kubota1, K. Nakayama1,2, T. Kawakami1, S. Souma3,4, K. Sugawara1,2,3,4,
S. Ideta5,6, K. Tanaka5,6, T. Takahashi1,3,4, K. Segawa7 and T. Sato1,3,4

Department of Physics, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency(JST), Tokyo 102-0076, Japan
3
Center for Spintronics Research Network, Tohoku University, Sendai 980-8577, Japan
4
Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, Sendai 980-8577, Japan
5
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
6
School of Physical Sciences, The Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan
7
Department of Physics, Kyoto Sangyo University, Kyoto 603-8555, Japan
1

2

Ⅲ-2

The search for novel fermions is recently becoming
an exciting challenge in condensed-matter physics, as
highlighted by the discovery of two-dimensional (2D)
Dirac fermions in graphene and helical 2D Diracfermions at the surface of three-dimensional (3D)
topological insulators. The recent discovery of 3D Diracfermions in topological Dirac semimetals (TDSs)
further enriches the category of exotic fermions. TDSs
show exotic quantum phenomena such as high carrier
mobility and giant linear magnetoresistance governedby the linearly dispersive Dirac-cone energy band. Also,
TDSs provide a fertile playground for realizing a variety
of topological phases, e.g., by breaking the timereversal/crystalline symmetry or by chemical substitution.
However, despite many theoretical predictions for TDS
candidates, TDSs that have been experimentally verified
are still rare. Moreover, topological phase transition
from TDSs has been scarcely realized partly because of
the difficulty in substituting constituent elements ofknown TDSs. Thus, it is highly desired to explore new
TDS materials that overcome such difficulties.
Here we demonstrate that ternary compoundBaMg2Bi2 is a new TDS and serves as a useful platform
to study topological phase transition [1].
High-quality single crystals of XMg2Bi2 (X = Ba andSr) were synthesized by the self-flux method. ARPES
measurements were performed with micro-focused
VUV synchrotron light at BL5U. Prior to the ARPES
measurements, samples were cleaved in an ultrahighvacuum.
Figure 1(a) shows the ARPES intensity near EF
measured along a momentum (k) cut crossing the Γpoint. One can see linearly dispersive bulk valence band
(VB) which crosses EF. To search for a possible band
touching of VB and conduction band (CB) predicted in
the calculation, we deposited K atoms onto the surface
in an ultrahigh vacuum. One can clearly see in Fig. 1(b)that the hole bands in K-deposited BaMg2Bi2 are shifted
downward due to the electron doping to the surface.
Intriguingly, VB in the negative k region appears toalmost continuously disperse across k = 0 and cross EF at
positive k, without losing its intensity at k = 0, indicativeof the formation of Dirac-cone dispersion. In contrast to
the case of K-deposited BaMg2Bi2, the spectral weightassociated with the CB is absent and no Fermi-edge cutoff is observed in K-deposited SrMg2Bi2 [Fig. 1(c)].
This observation demonstrates that an intrinsic band gap
opens in SrMg2Bi2, suggesting the occurrence of
topological phase transition from the TDS state to theordinary insulator phase upon replacing Ba with Sr [Fig.
1(d)].

Fig. 1. (a)-(c) ARPES intensity plot near EF in
BaMg2Bi2, K-dosed BaMg2Bi2, and K-dosed
SrMg2Bi2. (d) Schematic band diagram of XMg2Bi2.

[1] D. Takane et al., Sci. Rep. 11 (2021) 21937.

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Band-structure Reconstruction of Ca3Ru2O7 Induced by K Adsorption
M. Horio 1,2, T. Wada1, V. Granata3, R. Fittipaldi3, A. Vecchione3, K. Tanaka4,
I. Matsuda1 and J. Chang2
Institute for Solid State Physics, The University of Tokyo, Kashiwa 277-8581, Japan
Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
3
CNR-SPIN, I-84084 Fisciano, Salerno, Italy
4
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan1

2

Application of external perturbations to Mott
insulators often leads to dramatic changes in theelectronic structure. For example, the Mott insulator
Ca2RuO4 can be metallized by chemical substitutions[1,2], physical pressure [3], and electric current [4].
Changing the number of the RuO2 layer in the unit cellfrom one (Ca2RuO4) to two (Ca3Ru2O7), the system canalso become metallic down to low temperatures [5].
Instead, Ca3Ru2O7 exhibit a first-order phase transition
at T = 48 K that involves lattice and spin degrees of
freedom [6]. At 48 K, antiferromagnetically orderedspins change their orientation from the a to b crystalline
axis and the lattice undergoes slight compression along
the c axis. This phase transition makes a significant
influence on the transport properties such as resistivity,
Hall effect, and Seebeck effect [7], suggesting dramaticchanges in the band structure near the Fermi level.
Indeed, our recent angle-resolved photoemission
spectroscopy (ARPES) study [8] has revealed a clear
band-structure reconstruction into a Dirac-semimetallic
state upon cooling across 48 K.
Recently, alkali-metal adsorption is being recognized
as an efficient way to dope a solid surface with electrons.
This methodology has been applied to Mott insulatorssuch as iridates [9] and cuprates [10] and the occurrenceof metal-insulator transition has successfully been
demonstrated through in-situ ARPES measurements.
With this technique, electrons can be doped at thesurface even in the case where bulk electron doping bychemical substitutions is impossible. Ca3Ru2O7 is one
such case where electron doping has never been realized.
We have dosed K on Ca3Ru2O7 and carried out
ARPES measurements at BL5U at T = 10 K. Figure 1
shows energy distribution curves in a wide energy range.
As K is adsorbed on the surface, a peak at the binding
energy of ~1.7 eV, which is a remnant of the lower
Hubbard band, loses its intensity and instead a spectral
weight accumulates at the Fermi level. This spectralweight re-distribution suggests that the electronic statechanges away from the Mott insulating state. Thechange is even more clearly seen in the ARPES spectrain Fig. 2. Notably, the hole-like dispersion around the Γpoint expands, which is opposite to what is expectedfrom electron doping. It is therefore likely that the effectof adsorbed K atoms goes beyond simple electron doping
to cause the observed band structure reconstruction.

Ⅲ-2

Fig. 1. Energy distribution curves recorded withvarying the K deposition level.

Fig. 2. Electronic structure change in Ca3Ru2O7 by K
adsorption. (a)-(c) ARPES spectra of pristine and Kdosed Ca3Ru2O7. (d) Momentum distribution curves(MDCs) at E-EF = -0.02 eV.

[1] S. Nakatsuji and Y. Maeno, Phys. Rev. Lett. 84(2000) 2666.
[2] H. Fukazawa and Y. Maeno, J. Phys. Soc. Jpn. 70(2001) 460.
[3] S. Ricco et al., Nat. Commun. 9 (2018) 4535.
[4]R. Okazaki et al., J. Phys. Soc. Jpn. 82 (2013) 103702.
[5] Y. Yoshida et al., Phys. Rev. B 69 (2004) 220411(R).
[6] Y. Yoshida et al., Phys. Rev. B 72 (2005) 054412.
[7] H. Xing et al., Phys. Rev. B 97 (2018) 041113(R).
[8] M. Horio et al., npj Quantum Mater. 6 (2021) 29.
[9] Y. K. Kim et al., Science 345 (2014) 187.
[10] C. Hu et al., Nat. Commun. 12 (2021) 1356.

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Quadrupole Electronic Structure in Mn3-xGa Studied by Angle-resolved
Photoemission Spectroscopy
J. Okabayashi1, Y. Miura2, K. Tanaka3, K. Z. Suzuki4 and S. Mizukami4

Research Center for Spectrochemistry, The University of Tokyo, Tokyo 113-0033, Japan
2
National Institute for Materials Science (NIMS), Tsukuba 305-0047, Japan
3
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585
4
WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8579, Japan
1

Ⅲ-2

Magnetic ordered alloys have attracted significant
attention for use as spintronics materials because they
are highly likely to exhibit perpendicular magnetic
anisotropy (PMA). Tetragonal Mn3-xGa alloys arewidely recognized as hard magnets which exhibit highly
anisotropic, ferrimagnetic, and metallic properties [1].
We have investigated the mechanism of PMA and large
coercive fields in Mn3-xGa by x-ray magnetic circularand linear dichroisms (XMCD /XMLD) [2]. The origin
of PMA in Mn3-xGa alloys can be explained by thequadrupole contribution along the z-axis by the chargeasphericity. The specific crystalline structures provide theelongated c-axis direction, which induces the anisotropic
chemical bonding, resulting in the anisotropy of electron
occupancies in 3d states and charge distribution.
However, orbital magnetic moments in the Mn sites arealmost quenched because of half-filled occupation.
Although the site-specific charge distributions can beaccessed by x-ray absorption spectroscopies, the originof quadrupole-induced PMA from the viewpoint of theband structures in Mn3-xGa alloys is not fully understood.
Here, we employ the angle-resolved photoemission
spectroscopy (ARPES) to unveil the anisotropic band
structures in Mn3-xGa by the comparison with thedensity-functional theory (DFT) calculations.
30-nm-thick Mn3-xGa samples were prepared on
MgO (001) substrate using sputtering technique. On
the surface of Mn3-xGa layer, Mg and MgO capping
layers were deposited. The MgO layer was removed
by Ar-ion sputtering and the Mg layer was removed byannealing just before the ARPES measurements. We
construct the method to remove the Mg layer which
does not react chemically with Mn atoms at theinterface. Clear low-enegy electron diffraction (LEED)
patterns were also obtained.
ARPES was performed at BL5U, UVSOR, where
the photoemission chamber is connected to the sample
preparation chamber. The measurement conditions
were set at 15 meV energy resolution and 10 K. Linear
polarized beams of s- and p-polarization were used todetect the orbital symmetry. We employ the photon
energy ranges of 60 – 80 eV to enhance the Fe 3d
photo-ionization cross section, where the Γ-X(M) line
is scanned by the angular mode of ± 15°.
Figure 1 shows the Fermi surface mapping taken at
photon energy of 80 eV. Four-hold symmetric lines aredetected, which is consistent with the LEED patterns.

High intensity spots appear at both Γ and X points.
Nodal lines are also developed from each symmetricpoint. Energy-momentum (E-k) dispersion curves also
exhibit the intensities at Γ and X points with thedispersive bands. These bands are comparable with the
DFT calculation. The band from the Γ point has acharacter of yz orbital, which can be detected by the spolarized beam in vertical geometry.
We discuss the quadrupole formation. In the DFT
calculation, the virtual spin-flip transitions from occupied
up-spin yz to down-spin z2 orbitals correspond to thefinite matrix element to the PMA in the perturbation.
Therefore, occupied yz orbitals detected by ARPES
contribute to spin-flipped yz-z2 oblate quadrupolecharge distribution, resulting in the PMA. Ourfinding explains the origin of PMA in Mn3-xGa comesfrom not orbital moment anisotropy but elongatedcharge distribution through the spin-flipped transition in
specific orbitals, whose results are also supported by
XMCD and XMLD.

Fig. 1. ARPES images of Mn3Ga taken at hv=80 eV
using s-polarized beam. (a) The kx-ky mapping. (b)Band dispersions along Γ-X direction in primitive
Brillouin zone. Dot curves in (b) show the results of
DFT calculation.

[1] S. Mizukami et al., Scr. Mater. 118 (2016) 70.
[2] J. Okabayashi et al., Sci. Rep. 10 (2020) 9744.

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Change of the Fermi Surface of Bi2Sr2CaCu2O8Observed by ARPES
1

Y. Tsubota1, S. Kumar2, Y. Miyai2, K. Tanaka3, S. Ishida4, H. Eisaki4, S. Nakagawa5,
T. Kashiwagi5, M. Arita2, K. Shimada2 and S. Ideta2

Department of Physics, School of Science, Hiroshima University, Higashi-Hiroshima 739-0046, Japan
Hiroshima Synchrotron Radiation Center, Hiroshima University, Higashi-Hiroshima 739-0046, Japan
3
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
4
National Institute of Advanced Industrial Science and Technology, Tsukuba 305-8560, Japan
5
Division of Material Science, Tsukuba University, Tsukuba 305-8577, Japan2

It has been known that the cuprate superconductors
show a high superconducting (SC) transition
temperature (Tc) and exotic physical properties, on theother hand, the SC mechanism has been unclear yet. In
order to understand the mechanism of high-Tc cuprates,
Bi2Sr2CaCu2O8+δ (Bi2212) is one of the promising
candidates to study the electronic structure and reveal
the physical properties. Bi2212 has two CuO2 planes in
the unit cell and shows the high Tc around 95 K at the
optimally doped sample. Superconductivity occurs
upon hole doping into the CuO2 plane and the amountof hole doping can control Tc, and therefore, carrier
doping (hole/electron concentration) plays an important
key parameter in cuprates [1,2]. According to theprevious report, we consider that differences of theelectronic states in Bi2212 depending on the sample
with several compositions might exist, even thoughsamples are expected to be the same hole concentration,
where the optimally doped sample shows the maximum
Tc (Tc,max); however, the compositions are different,
which shows a different Tc,max [1,2]. Therefore, in thepresent study, we have performed an angle-resolved
photoemission spectroscopy (ARPES) measurements tostudy the Fermi surface changes of Bi2212 due todifferences in sample compositions.
We have demonstrated ARPES measurements toinvestigate the electric structure on wide momentum
space for Bi2212 with two compositions. ARPES
experiments were carried out at BL5U and we measured
two optimally doped samples: Bi2.3Sr1.7CaCu2O8+δ, (Tc ~85 K) and Bi2.1-xPbxSr2CaCu2 O8+δ (x = 0.66, Tc ~ 95 K)
in the SC and the normal states. High quality single
crystals of Bi2212 were cleaved in-situ in the ultrahighvaccume ~4×10-9 Pa.
Figures 1(a) and 1(b) show the Fermi surfaces taken
at hν = 60 eV and T = 30 K in the SC state forBi2.3Sr1.7CaCu2O8+δ and Bi2.1-xPbxSr2CaCu2O8+δ (x =0.66), respectively. Fermi surfaces are clearly observedin wide momentum space for both samples. In Fig. 1(a),in addition to the main Fermi surfaces as shown by a redarrow at -0.4 Å–1 in momentum space on the horizontal
axis, the spectrum at -0.2 Å–1 in momentum space isobserved, indicating that the modulation from the BiO
layer, so called replicas, is observed as shown by a blue
arrow. If replicas are observed in the ARPES results, wecannot understand the electric structure precisely inmomentum space because the main and replica bands

are overlapped. Figure 1(b) shows Fermi surfaces of
Bi2.1-xPbxSr2CaCu2O8+δ (x = 0.66). Substitution of the Bi
site with Pb suppresses the modulated structure from the
BiO layer and as a result, the replica is strongly
suppressed. In Fig 1(b), the replicas on Fermi surfaces
are well suppressed and the main bands are dominantly
observed.
We have analyzed the ARPES spectra around thenodal region for each sample and determined the
Fermi momentum (kF) for each Fermi surface byfitting of momentum-distribution curves (MDCs) witha Lorentzian. The kF’s are plotted as shown by red dots
(Fig. 1). As a result, we have found that two samples
with different compositions show that the distance
between two nodal points has a different value. Thismeans that the Fermi surface might change due todifferences in sample compositions. As a future work,
we will demonstrate ARPES experiments in a different
composition and doping level.

Fig. 1. Electronic structure of Bi2212. (a) Fermi surfacesof Bi2.3Sr1.7CaCu2O8+δ in the superconducting state (30K). (b) Fermi surfaces of Bi2.1-xPbxSr2CaCu2O8+δ (x =0.66) in the superconducting state (30 K). Main Fermi
surfaces are shown by a red arrow. Red dots are theFermi momentum estimated from the MDC peak near
the Fermi level.

[1] J. L. Tallon et al., Phys. Rev. B 51 (1995) 12911.
[2] I. M. Vishik et al, Proc. Nat. Acd. Sci. 6 (2012)
18332.

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CDW-induced Electronic Reconstruction in a Kagome Metal KV3Sb5
T. Kato1, K. Nakayama1,2, T. Kawakami1, A. Moriya1, Yongkai Li3,4, Z. Wang3,4, S. Ideta5,6,
K. Tanaka5,6, T. Takahashi1,7,8, Y. Yao3,4 and T. Sato1,6,7

Department of Physics, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency(JST), Tokyo 102-0076, Japan
3
Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture andMeasurement (MOE), School of Physics, Beijing Institute of Technology, Beijing 100081, China
4
Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology,
Beijing 100081, China
5
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
6
School of Physical Sciences, The Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan
7
Center for Spintronics Research Network, Tohoku University, Sendai 980-8577, Japan
8
Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, Sendai 980-8577, Japan
1

2

Ⅲ-2
Recently, a new kagome-lattice material AV3Sb5 (A= K, Rb, and Cs) has been discovered. AV3Sb5
undergoes a charge-density wave (CDW) transition
below TCDW = 78-103 K, accompanied by the in-plane
unit-cell doubling with the 2×2 periodicity. This CDW
state shows an intriguing entanglement with thesuperconductivity (transition temperature Tc of 0.9-2.5
K) and non-trivial topological surface states. Also,
exotic properties, e.g., strong anomalous Hall effectand possible time-reversal symmetry breaking havebeen reported, highlighting the unconventional natureof CDW.
Despite intensive studies, the origin of CDW in
AV3Sb5 is highly controversial. In particular, the type ofstructural distortion responsible for the CDW has yet to
be clarified. First-principles calculations proposed two
types of distortions sharing the same space group toaccount for the in-plane 2×2 periodicity. One is the“Star-of-David” (SoD) distortion of V atoms. The otheris an inverse type of the SoD distortion, where V atoms
show an opposite displacement compared with the SoD
case, resulting in a periodic arrangement of triangularand hexagonal patterns, called “Tri-Hexagonal” structure.
It is experimentally highly controversial which distortion
actually takes place.
To gain insight into the origin of CDW from theelectronic structure perspective, we have performedhigh energy and spatial resolution ARPES of KV3Sb5 byusing a micro-focused beam at BL5U in UVSOR [1].
Figure 1 shows a side-by-side comparison of the
ARPES intensity plots along the M-M cut measured in
the normal and CDW states (left and right panels,
respectively). In the normal state, one can see a strong
intensity near the Fermi level (EF) at the M point,
together with a hole-like dispersion topped at slightly
below EF at the M point. One can recognize an obvious
difference in the intensity distribution in the CDW
phase. A new shallow holelike bands crossing EF
appear at the middle of the two M points, as also
identified from the momentum distribution curve at EF(white curves shown in the inset; folded bands arehighlight by white triangles). This indicates the CDWinduced band folding. A comparison of the observed
electronic reconstruction with the band structure
calculations assuming SoD/TrH structural distortion
would help to clarify the origin of CDW.

Fig. 1. ARPES intensity measured along the M-M cut
at T = 120 K (left) and 20 K (right), respectively. White
curve in the inset shows the MDC at EF.

[1] T. Kato et al., submitted.

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Electronic Structure of VNb3S6: a Transition-metal Intercalated NbS2
M. Horio 1, T. Wada1, S. Okazaki2, K. Tanaka3, T. Sasagawa2 and I. Matsuda1

Institute for Solid State Physics, The University of Tokyo, Kashiwa 277-8581, Japan
Materials and Structures Laboratory, Tokyo Institute of Technology, Yokohama 226-8503, Japan
3
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
1

2

Transition-metal dichalcogenides MX2 host a richvariety of physical phenomena such as superconductivity[1] and charge density wave [2], and thus have attracted
intense interest for decades. In 1970-1980’s, there havebeen extensive attempts to modulate its electronic
structure by intercalation of 3d transition metals T [3].
Thus made TM3X6 takes crystal structure with broken
inversion symmetry and shows various types ofmagnetic order depending on the intercalated 3dtransition metal. Out of these, CrNb3S6 has been mostintensively studied because of the special type ofmagnetic order called chiral soliton lattice.
In Recent years, due to the breaking of both theinversion and time-reversal symmetry, TM3X6 isattracting interest from a topological perspective.
Especially, VNb3S6, which shows a ferromagnetic order
below TC ~ 44 K, has been theoretically predicted topossess a magnetically induced Weyl point. Indeed, arecent study has demonstrated large anomalous Hall
conductivity potentially associated with the proposed
Weyl point [4]. While there recently appears increasing
number of ARPES reports made for CrNb3S6 [5,6],
MnNb3S6 [7], FeNb3S6 [8], CoNb3S6 [8-10], andNiNb3S6 [7,8], to the best of our knowledge there havebeen no such studies on VNb3S6. We therefore attempted
an ARPES measurement to reveal the low-energy
electronic structure of VNb3S6.
Single crystals of VNb3S6 were grown by the chemical
vapor transport method from polycrystals with iodine as
the transport agent. ARPES measurements were
performed at BL5U of UVSOR at temperatures ranging
from 10 to 200 K.
Figures 1(a) and (b) show the Fermi surface and band
dispersions through the Brillouin-zone center of VNb3S6,
respectively, recorded at 10 K. From these, three holelike Fermi surface sheets centered around the zone
center can be clearly identified. This result is distinct
from the observations for the antiferromagnets FeNb3S6,
CoNb3S6, and NiNb3S6 [7-10], where there is only single
Fermi surface. Instead, the Fermi surface structure
resembles what was reported for the ferromagnet
CrNb3S6 [5,6]. In the case of CrNb3S6, from temperaturedependent systematic APRES measurements across TC[6], the emergence of multiple Fermi surface sheets has
been ascribed to the effect of ferromagnetism. In contrast,
as for VNb3S6, the band structure is remarkably robust
against temperature variations up to 200 K (Fig. 1), farabove TC ~ 44 K. Therefore, the peculiar band structure
is likely not rooted in magnetism. Comparisons with
first-principles band structure calculations both in themagnetic and non-magnetic states would pave the way
to understanding the origin of these observations.

Ⅲ-2

Fig. 1. ARPES results of VNb3S6. (a),(b) Fermi
surface and band dispersions, respectively, measured
at 10 K. The momentum cut for (b) is indicated in (a).
(c),(d) The same plots at 50 K. (e),(f) The same plots
at 200 K.

[1] T. Yokoya et al., Science 294 (2001) 2518.
[2] J. Wilson et al., Adv. Phys. 24 (1975) 117.
[3] S.S.P. Parkin et al, Philos. Mag. B 41 (1980) 65.
[4] S. Okazaki et al., JPS annual meeting (2021).
[5] N. Sirica et al., Phys. Rev. B 94 (2016) 075141.
[6] N. Sirica et al., Commun. Phys. 3 (2020) 65.
[7] C. Battaglia et al., Eur. Phys. J. B 57 (2007) 385.
[8] H. Tanaka et al., Phys. Rev. B 105 (2022) L121102.
[9]X. P. Yang et al., Phys. Rev. B 105 (2022) L121107.
[10] P. Popčević et al., arXiv:2111.12529

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Angle-resolved Photoemission Study of Zr3SnC2
1

Ⅲ-2

T. Ito1,2, M. Mita2, D. Pinek3, M. Nakatake4, K. Tanaka5,6 and T. Ouisse3

Nagoya University Synchrotron radiation Research center (NUSR), Nagoya University, Nagoya 464-8603, Japan
2
Graduate School of Engineering, Nagoya University, Nagoya 464-8603, Japan
3
Grenoble Alpes, CNRS, Grenoble INP, LMGP, F-38000 Grenoble, France
4
Aichi Synchrotron Research Center, Seto 489-0965, Japan
5
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
6
The Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, JapanMAX phase compounds, i.e., Mn+1AXn where M is atransition metal, A belongs to groups 13-16 and X is the
C or N element, have recently been attracted muchattention due to their possible application for new classof two-dimensional systems called MXenes by removing
A atoms [1]. Zr3SnC2 is so called 312 MAX phase inwhich Zr3C2 layers separated by Sn layer, then two
dimensionality becomes higher than 211 phase. In
addition, relatively stronger spin-orbit interaction of Zr
and Sn 4d is expected to affect its physical properties.
In this study, we have performed angle-resolved
photoemission spectroscopy (ARPES) on MAX phasecompound Zr3SnC2 to directly investigate the electronic
structure of this system.
ARPES measurements were performed at the
UVSOR-III BL5U. Data were acquired at T = 30 K withhν = 82 eV which enables us to trace around the ΓKM
plane with inner potential of V0=17.7 eV estimated fromthe photon energy dependent measurement (not shown).
Figure 1 shows the obtained Fermi surface (FS)image on the ΓKM plane of Zr3SnC2. Along the ΓMand ΓKM high-symmetry lines (orange lines), we haveextracted the band structure image as shown in Fig. 2.
We have found that the electronic structure near the
Fermi level (EF) consists of two hole-pockets aroundΓ point and relatively intense dispersive feature justbelow EF around M point. While the former seems tobe similar with DFT calculation, the latter feature has
appeared in the blank of bulk DFT bands around theM(L) point. Therefore, we assigned the dispersive
feature around the M(L) point to be surface state. Fromthe band structure near EF (Fig. 3(a)), the observed
surface state was formed by characteristic saddle-like
dispersive feature (Fig. 3(b)), in which the saddlepoint locates around 150 meV at the M(L) point. Fromthe saddle-like dispersion, it has been expected that thenarrow dispersive feature along MK line forms pair oftriangular FS around M point, which has been clearlyobserved in Fig.1. To clarify the essential role of thesurface states, further studies with using liner/circularpolarization and spin-resolved ARPES are intended.

Fig. 1. Fermi surface image of Zr3SnC2. Orange thicklines indicate the high-symmetry lines on which the
ARPES image has been extracted in Fig. 2.

Fig. 2. Band structure (lower panel) and MDC spectraat EF (upper panel) along ΓM and ΓKM lines of Zr3SnC2.
Blue solid and dashed lines are DFT calculation along
the MΓK and AHL lines, respectively.

Fig. 3. (a) Band structure near EF around M point of
Zr3SnC2. (b) Example of saddle-like dispersive feature,in which M point corresponds to the saddle point.
[1] M. Basoum, MAX phases (Wiley, Weinheim 2013).

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Fermi Surface Measurements of TiSe2 with the CDW Transition
S. Tanaka 1, K. Ueno2 and K. Tanaka3

Sanken, The Institute of Industrial and Scientific Research, Osaka University, Ibaraki 567-0047, Japan.
2
Graduate School of Science and Engineering Saitama University, Saitama 338-8570, Japan.
3
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan.

1studies for investigating the driving force of theinterlayer CDW transition in TiSe2 is under progresswith a help of the DFT calculation.

6.0

5.5

5.0

kz (Å-1)

-1.0

-0.5

kx (Å-1)

0.0(a)300KL2/c 

4.5

0.5

4.0

6.0

5.5

5.0

kz(Å-1)

Transition metal dichalcogenides (TMDs) are aclass of materials attracting high scientific interest in
recent years. They are layered materials where theinterlayer distance is considerably larger than theintralayer atomic distance yielding a quasi-two
dimensional character. Charge density wave (CDW)
transition, which is a transition accompanying aperiodical superlattice formation below the transition
temperature, is one of the typical phenomena of the
low-dimensional system, and has been attracted many
researchers. Among TMDCs, (1T-)TiSe2 exhibits very
unique character; its CDW transition provides the 2a
× 2b × 2c superlattice formation where the interlayer
periodic distortion occurs. Although several studies,including ARPES studies, have been made forrevealing the driving force of the CDW transition in
TiSe2, rather few were made for investigating theinterlayer interaction. In this work, we investigate thechange in the Fermi surface of TiSe2 along theinterlayer axis due to the CDW transition by measuring
the photon-energy dependent ARPES.
The experiments were carried out at BL5U of UVSOR.
The temperature of the cleaving/measurements ofsingle-crystalline TiSe2 were 300K and 10K, which arerespectively above and below the CDW transitiontemperature (about 200K). The (lateral) CDW formation
at 10K was examined by the folding of the valenceband from Γ(A) point to M(L) point in the ARPES
spectrum. Figure 1 show intensity maps of thephotoelectron at the Fermi level, demonstrating the
Fermi surface along the Γ-M-L-A plane. The horizontal
axis is along the Γ-M(A-L) line derived from theangular distribution of the photoelectron, and thevertical axis is along the inter-layer axis (kz) derived
from the photon-energy dependent measurements. For
deriving value of kz, the free-electron final state is
assumed, and 13.5eV is used as the inner potential
after the reference[1].
At 300K [Fig. 1(a)], the Fermi surface of theelectron-pocket near the M(L) point shows a tilted
elliptical shape. This structure is periodic (except thevariation of the intensity) along the kz axis with a 2π/c
distance which is the periodicity of the inverse lattice.
This is consistent with the DFT calculation (not shownhere). When the CDW transition occurs at 10K,
meanwhile, the periodicity of the Fermi surface along
the kz axis shrieks as half of that at 300K [Fig. 1(b)]. It
is due to the superlattice formation whose lattice
constant along the inter-layer axis c* = 2 × c. It is a veryclear evidence of the CDW transition of TiSe2
accompanies the periodic interlayer distortion. Further0kx(Å-1) 1(b)10K

L*








2/c*

L*


4.5

4.0

Fig. 1. Intensity maps of the photoelectron at the
Fermi level of TiSe2. The horizontal axis is along theΓ-M(A-L) line derived from the angular distribution of
the photoelectron, and the vertical axis is along kz axis
derived from the photon-energy dependent measurements.
The sample temperature is 300K (a) and 10K (b).

[1] M. D. Watson et al., Phys. Rev Lett. 122 (2019)076404.

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Temperature Dependence of Electronic Structure in Pb-doped La(O,F)BiS2
Superconductor
1

Ⅲ-2

N. Kataoka1, L. Y. Jun1, T. Setoguchi1, S. Demura2 and T. Yokoya1,3

Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
2
Nihon University, Tokyo102-8275, Japan
3
Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan

BiCh2 compounds are quasi-two-dimensional materials
with a layered structure typically represented by thecomposition of REO1-xFxBiCh2 (RE=rare earth; Ch=S,
Se). It can be doped electrons by replacing oxygen withfluorine atoms, and electron-doped samples exhibit
superconductivity below 2-10 K. Several experimental
and theoretical studies have indicated the possibility of
unconventional superconducting mechanisms [1]. Since
the superconducting transition temperature is sensitive
to the pressure applied to the BiCh2 planes, the effects
of many elemental substitutions have been intensively
studied [1-2]. Elemental substitution effects are importantfor understanding the superconducting mechanism,
although there are few reports on the electronic structure.
Pb-doped La(O,F)BiS2 shows an anomalous behavior
with a sharp decrease in electrical resistance around 100
K, but the origin of this behavior is unknown [2]. In thisstudy, we performed temperature-dependent angleresolved photoemission spectroscopy (ARPES)
measurements of Pb-doped La(O,F)BiS2 above andbelow the temperature at which an anomaly in electricalresistance appears in order to investigate the cause of
the anomalous electrical resistance.
The measurements were performed using the
LaO0.5F0.5Bi0.9Pb0.1S2 single crystals synthesized by
the flux method [2]. The temperature at which theanomaly appears is estimated to be about 100 K fromthe temperature dependence of the electrical resistance.
ARPES measurements were performed at BL5U of
UVSOR III. We used the 70 eV photons, and theenergy resolution was 35 meV. All samples werecleaved in situ on the (001) plane in an ultrahighvacuum of less than 5.0×10-9 Pa. The temperaturedependence of the electronic structure was measured
in the range of 50-150 K.
Figure 1 shows the Fermi surface mapping from the
ARPES intensity between ±25 meV of the Fermi
energy (EF) measured at 70 K and 150 K. Figure 2
shows the angle-integrated energy distribution curves(EDCs) in the X-M and Γ-X directions measured at 70
K and 150 K. The Fermi surface shape was found to
be in good agreement with the previously reported
La(O,F)BiS2 (F concentration = 0.5) [3], with nosignificant difference in the Fermi surface shape at 70
K and 150 K, respectively. On the other hand, the EDC
intensity in the X-M and Γ-X directions at 70 K
decreased from EF to around 0.2 eV and increasedaround 0.3-0.6 eV, compared to those at 150 K.
Reproducibility of the results were checked for several

samples. Therefore, this EDC change is considered to
be a change in the electronic structure due to an anomaly
in the electrical resistance.

Fig. 1 Temperature dependent Fermi Surfaces mapof LaO0.5F0.5Bi0.9Pb0.1S2 at (a) 70 K and (b) 150K.

Fig. 2 Angle-integrated EDCs in each direction (top:
X-M, bottom: Γ-X). Spectral intensities were normalized
by area intensity in the range EB = -0.1~0.8 eV. The
angles are integrated about ± 6° around the X point.

[1] Y. Mizuguchi J. Phys. Soc. Jpn. 88 (2019) 041001.
[2] S. Otsuki et al., Solid State Commun. 270 (2018) 17.
[3] K. Terashima et al., Phys. Rev. B 90 (2014)
220512(R).

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Evaluation of Self-Energy in Overdoped Bi2201 by Angle-Resolved
Photoemission Spectroscopy
Y. Miyai1, Shiv Kumar2, T. Kurosawa3, M. Oda4, S. Ideta2 and K. Shimada2

Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
Hiroshima Synchrotron Radiation Center, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
3
Fuculty of Science and Engineering, Muroran Institute of Technology, Muroran 050-8585, Japan
4
Department of Physics, Hokkaido University, Sapporo 060-0809, Japan
1

2

High-Tc cuprate superconductors have attracted
much interest since their discovery in 1986 for theirhigh Tc as well as unusual physical properties such as
bad metal states and formation of density waves [1, 2].
However, the high-Tc mechanism has not been fully
understood yet, and therefore, it is necessary to study
the physical properties from the microscopic point ofview. Angle-resolved photoemission spectroscopy(ARPES) is one of the most effective and direct
experimental methods to investigate the electronic
structure in solids. ARPES spectra are related to theimaginary part of the one-particle Green’s function
and give the quasiparticle excitation spectrum. The
one-particle Green's function includes the self-energy
derived from the many-body interactions such as theelectron-phonon, electron-electron, and electronimpurity interactions. By analyzing the ARPES
spectral lineshape quantitatively, one can directly
evaluate the magnitudes of each many-body interaction.
The previous ARPES studies of cuprates have focusedon the investigation of the electron-boson interaction
at the vicinity of the Fermi level [3]. In the previous
studies, the real part of the self-energy due to theelectron-electron interaction was usually estimated bya line [4]. However, the energy dependence of the selfenergy due to the electron-electron interaction is nottrivial in the wide energy range. It is assumed to induce
a so-called “waterfall” structure or a sudden spectral
intensity suppression in the ARPES spectra [5]. To
understand the mechanism of the high-Tc cuprate
superconductivity, it is also important to quantify themagnitudes of the electron-electron interaction as wellas electron-phonon(boson) interaction [3].
In this study, to quantitatively evaluate the electronboson interaction and the electron-electron interaction
simultaneously, we have performed a high-resolution
ARPES study using synchrotron radiation on the Bibased high-TC cuprate (Bi,Pb)2Sr2CuO6+δ (Pb-Bi2201)
in the wide momentum and energy ranges. We haveselected overdoped Pb-Bi2201 with TC = 6K because
it has a relatively simple electronic structure whichallows us to precisely evaluate the self-energy in thenormal state (i.e., normal self-energy). While it has
been expected that heavily hole-doped cuprates would
behave as the 2D Fermi Liquid, ferromagnetic
fluctuation has been found recently [6].
Figures 1(a) and 1(b) show ARPES intensity plots

taken at hν = 60 and 75 eV, respectively. Based on thelineshape analyses using the tight-binding model (here
we only considered the x2-y2 band), we have evaluatedthe self-energy in the wide energy range. Figure 1(c)shows the simulation of the ARPES intensity plotusing the evaluated self-energy. We clarified that thereal part of the self-energy crosses the zero line at theenergy of E – EF ~ -0.5 and the imaginary part of selfenergy has the maximum at that energy (Dashed line
in Fig. 1). Because the imaginary part of the selfenergy gives the spectral linewidth, the waterfall
structure is caused by the suppression of the spectral
intensity due to the significant broadening of thelinewidth at E – EF ~ -0.5 eV due to the electron-electroninteraction. In order to further reproduce the spectral
intensity, the matrix element and contribution fromother bands at the bottom of the x2-y2 band is required.

Fig. 1. Electronic structure of Pb-Bi2201. (a), (b)ARPES intensity plots taken at hν = 60 and 75 eV,
respectively. (c) Simulated ARPES intensity plots
using the evaluated self-energy. A solid black curve isthe x2-y2 band in the tight binding model.

[1] P. Choubey et al., Proceedings of National Academyof Sciences. 117 (2020) 14805.
[2] Y. Y. Peng et al., Nature Materials. 17 (2018) 697.
[3]I. M. Vishik et al., Phys. Rev. Lett. 104 (2010) 207002.
[4] H. Anzai et al., Scientific Reports. 7 (2017) 4830.
[5] D. S. Inosov et al., Phys. Rev. Lett. 99 (2007) 237002.
[6] K. Kurashima et al., Phys. Rev. Lett. 121 (2018)
057002.

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Multi-atom Resonance Photoemission from the Valence Band of TiSe2
S. Tanaka1, K. Ueno2, K. Fukutani3 and F. Matsui3

Sanken,Osaka University, Ibaraki567-0047, Japan
Graduate School of Science and Engineering Saitama University, Saitama 338-8570, Japan
3
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
1

2

Ⅲ-2

“Multi-atom resonant photoemission” (MARPE),
which is an interatomic resonant photoelectron emission
from neighboring atoms of the core-excited atoms,
was reported first for the O1s photoelectron emission
at the Mn-2p excitation edge in MnO [1], and attracted
significant attention. In this report, we report the
MARPE effect on, for the first time, the valence bandin TiSe2 analyzed with the momentum-resolved
constant initial state (MR-CIS) spectroscopy using the“Momentum Microscope” apparatus recently installed
at BL6U in UVSOR-III, IMS [2].
Figure 1(a) shows a CIS spectrum of TiSe2 at the TiL3 edge for the whole valence band (0-5.5 eV). The
spectrum is well represented by two symmetric
Lorentzian peaks. Meanwhile, in Fig. 1(b), the MR-CIS
spectrum for a specific state [M-point at the binding
energy of 2.0 eV; shown in Fig. 1(c)] is well reproducedby the sum of two Fano-shaped strongly asymmetriccurves. According to our photon-energy dependent
ARPES studies and DFT calculations (not shown here),
this state is mainly provided by Se-4p, while most of thevalence band is provided by Ti-3d. The symmetricshape in Fig. 1(a) indicates that the interference between
the direct photoexcitation from Ti-3d and the intraatomic Auger process does not occur since the former
probability is so small at this photon energy range [3].
On the contrary, it is suggested that the probability ofthe photoemission from Se-4p is comparable to that of
the inter-atomic Auger decay of Ti-2p core hole, and theinterference yields the Fano-type asymmetric shape. It
should be noted that he Fano parameter q is negative inthe present case, contrary to the conventional resonant
photoelectron emission. More work will be needed toreveal the physical origin of negative q.

Fig. 1. (a) CIS spectrum for the whole valence bandat the Ti-L3 edge, (b) The MR-CIS spectrum at the
specific states (M-points at the binding energy of 2.0eV), which are shown as bright spots in thephotoelectron intensity map (c), where the hexagon is
the Brillouin zone of TiSe2.

[1] A. Kay et al., Science 281 (1998) 679;J. Electr.
Spectrosc. Rel. Phenom. 114-116 (2001) 1179.
[2] F. Matsui et al. J. Phys. Soc. Jpn. 90 (2021) 124710.
[3] J. J. Yeh and I. Lindau, Atom. Data and Nucl. Dat

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Temperature-dependent Electronic Structure of η-Mo4O11 Revealed by
Photoelectron Momentum Microscopy
T. Kobayashi1, E. Iwamoto2, K. Sakamoto2, F. Matsui3 and S. Suga4

Department of Material and Life Science, Osaka University, Suita 565-0871, Japan2
Department of Applied Phisics, Osaka University, Suita 565-0871, Japan
3
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
4
SANKEN, Osaka University, Ibakaki 567-0047, Japan1

η-Mo4O11 is a pseudo two-dimensional material thatconsists of alternating layers of octahedral structure,
which contributes to electrical conduction, andtetrahedral structure, which do not contribute toelectrical conduction. Owing to the connection ofoctahedral structure in a form of one-dimensional
chain, η-Mo4O11 can be classed as a material withhidden one-dimensionality. A two-step anisotropic
charge density wave (CDW) transition at 109 K (TC1)and 30 K (TC2) has been reported for this material bytemperature-dependent conduction measurement [1],and this transition was supported by the observation ofchange in lattice periodicity [2]. However, though agap opening and band folding is predicted in case of
CDW transition, such phenomena were not observedin the band structure [3]. Therefore we have performed
photoemission measurements of η-Mo4O11 at different
temperatures in order to observe traces of CDW in theband structure.
Figures 1 and 2 show the Fermi surface and the band
dispersion at ky=0 Å–1 measured at T=20 K. The thinsolid black lines in Figs. 1 and 2 represent the Brillouinzone boundaries. The Fermi surface in Fig. 1 looks
different from that reported previously in Ref. [3],probably due to the difference in the energy of theexcitation light. The energy used in the present study
would make the band visible only in the first Brillouinzone, but not in the second one. In other words, we can
explain the results in Ref. [3] by considering the bands
in the second Brillouin zone.
Figure 3 shows the photoelectron intensity
distribution near the Fermi level. As can be seen in thisfigure, no band gap opening or band folding can beobserved even when the temperature is varied acrossthe transition temperatures, and metallic electronic
states are always observed. This result suggests thatthe charge density wave transition in η-Mo4O11 may be
a metal-metal transition. The nesting vector determinedin previous studies is qc1=0.23b* and qc2=0.55a*+
0.47b*+0.28c*, suggesting that the charge density
wave phase has a fairly long period structure. As aresult of the minute modulation of each atom, weconsider that the band structure of the metallic phase
may not be much affected. This idea is consistent withthe slow increase of resistivity below TC1, and thedecrease in resistivity indicating the metallic characterof this material below TC2.

Ⅲ-2

Fig. 1. Fermi surface of Mo4O11 measured at T = 20 K.

Fig. 2. Band dispersion at ky=0 Å–1.

150 K
70 K
20 K

Fig. 3. Temperature-dependent photoelectron intensity
distribution near the Fermi level.

[1] H. Guyot et al., J. Phys. C 16 (1983) L1227.
[2] H. Guyot et al., J. Phys. C 18 (1985) 4437.
[3] G.-H. Gweon et al., Phys. Rev. B 72 (2005) 035126.

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Characterization of CVD Graphene on Ir(111)/α-Al2O3(0001)
by Photoelectron Momentum Microscope
E. Hashimoto1, K. Tamura1, H. Yamaguchi1, F. Matsui2 and S. Koh1

Department of Electrical Engineering and Electronics, College of Science and Engineering, Aoyama Gakuin
University, Sagamihara 252–5258, Japan
2
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan1

Ⅲ-2

Chemical vapor deposition (CVD) is a promising
method to synthesize high-quality transferrable graphenesheets for device applications. We have previously
reported growth of high-quality graphene on Ir(111)/αAl2O3(0001) by a low-pressure CVD method anddemonstrated the reusability of the substrates [1-2]. In
this study, we characterized the crystallinity ofgraphene/Ir(111)/α-Al2O3(0001) and the electronicinteraction between graphene and Ir(111) using
photoelectron momentum microscope (PMM) [3].
We carried out CVD growth of graphene on theIr(111)/α-Al2O3(0001) substrates, using CH4 and H2 asprecursors at 1000 °C. The gas flow rate of hydrogenand methane were 100 : 10 (#1), and 200 : 10 (#2),
respectively. For both #1 and #2, the 2D and G peaks
for graphene were observed in the Raman spectra. We
characterized the samples (#1 and #2) by valence-band
photoelectron spectroscopy (VB-PES) using PMM at
the linearly polarized soft X-ray beamline BL6U of the
UVSOR-III synchrotron.
Figures 1(a) and (b) show the Iso-energy crosssections of the 2D band dispersion at Fermi energy forsample #1 and #2, respectively. The distinct patterns
with 6-fold symmetry were observed, which suggeststhat the sharp pattern with a low background corresponds
to high single crystallinity of graphene. By comparing
the patterns for #1 and #2, we found that #1 had thehigher single crystallinity for several hundred µm2 and#2 included the 30° rotated domains (R30). The growthof R30 domains was promoted by the fast growth rate,
which was attributed to the higher hydrogen gas flowrate in the CVD growth condition for #2.
Figures 2(a)-(d) show the momentum-resolved VBP
spectra of graphene on Ir(111). No Dirac points wereobserved in the VBP spectra along the KΓK direction
because the Fermi level located below the Dirac points,
which suggests that the charge transfer from graphene
to Ir(111) occurred. The binding energy of the M saddle
point, which was evaluated from the VBP spectra alongMΓM direction, reflected the amount of charge transfer.
The binding energy of the M saddle point for #1 and #2
were 2.30 eV and 2.25 eV, respectively. The lower
binding energy for #2, i.e., the higher amount of chargetransfer, can possibly be attributed to the presence of therotated domains (R30) in #2. The binding energy for
R30 was reported to be 0.06 eV lower than that for theperfectly aligned domains [4].
Through this study, we found that the relationship ofcrystal orientations and the degree of electronicinteraction between graphene and the Ir(111) depended
on the CVD growth conditions of graphene, for which
PMM is a powerful complementary characterization
tool to conventional methods (e.g., Raman spectroscopy
and AFM) for comprehensive characterization ofgraphene/Ir(111).

Fig. 1. Iso energy cross sections of 2D band dispersion
at Fermi energy for (a) #1, (b) #2.

Fig. 2. Momentum-resolved VBP spectra of graphenefor (a) #1 along KΓK direction, (b) #1 along MΓM
direction, (c) #2 along KΓK direction, and (d) #2 alongMΓM direction.
[1] S. Koh, Y. Saito, H. Kodama, and A. Sawabe, Appl.
Phys. Lett. 109 (2016) 023105.
[2] A. Sakurai et al., Jpn. J. Appl. Phys. 59 (2020)
SIID01.
[3] E. Hashimoto et al., Jpn. J. Appl. Phys. (2022) inpress.
[4] E. Starodub et al., Phys. Rev. B 83 (2011) 125428.

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Vibrational Spectroscopy of Pentacene Single Crystals in the Mid to Far
Infrared Region and its Temperature Dependence
J. Miyamoto, A. Sugiyama, K.Yamauchi and Y. Nakayama

Department of Pure and Applied Chemistry, Tokyo University of Science, Noda 278-8510, Japan
Charge transport in organic semiconductor molecules
has become an important issue in the pursuit of organic
semiconductor devices with excellent efficiency.
However, the decrease in carrier mobility due tomolecular vibration is a particular problem for organic
semiconductors, and the elucidation of the vibrational
interactions that limit the charge carrier transport
efficiency is one of the most important subjects in thefield of organic semiconductors. In this study, we
carried out mid-to-far infrared absorption spectroscopyon the single crystal pentacene (C22H14), a typical ptype organic semiconductor material, and attempted to
track its temperature dependence.
First, single crystals of pentacene were preparedusing the physical vapor transport (PVT) method andfixed to chemical-vapor-deposited (CVD) diamondsubstrates (5 mm × 5 mm × 0.4 mm). Infrared (IR)absorption measurements were performed in atransmission configuration at room temperature (RT)or low temperatures (100 K, 40 K). A blank CVD
diamond substrate as a reference sample was alsomeasured in identical conditions.
The measurement results are expressed in the top
panel of Fig. 1 in terms of the IR absorbance which
was derived from the relative transmittance of thepentacene/diamond sample with respect to the blankdiamond sample. Quantum-chemical calculation
results (Gaussian09, b3lyp, 6-31g*) for intramolecularvibration modes and calculated intermolecular Ag and
Au phonon modes of the pentacene single crystals
taken from a literature [1] are shown in the lower
panels of Fig. 1. To track how the absorption intensityand peak positions change when the effect of thermal
vibration is reduced by cooling, the measurements
were performed at three different temperatures (RT,100 K, and 40 K). Figure 1 shows two peaks around460~500 cm-1 for the spectra at RT and 100 K.
Whereas, the calculation results predict three modes
around 480~500 cm-1, the former two modes were
presumed to be merged in the experimental spectra.
Although, the two peaks appeared in a low wavenumber
region compared to the calculated positions. On theother hand, the spectrum at 40 K exhibited a single peak,
instead of two, at approximately the same wavenumber
as the calculation results. The reason for this is unclear
at this stage, but may be attributed to changes inintermolecular interactions as previously reported as
shifts in Raman bands for amorphous thin-films of
N,N’-di-naphthaleyl-N,N’-diphenyl-1,10-biphenyl-4,4’diamine and copper-phthalocyanine [2].

For the spectral features below 200 cm-1 observed inFig. 1 are not able to be assigned to which vibrations
at this stage mainly due to a poor signal-to-noise ratio.
More accurate and reliable measurements in thiswavenumber region are future subjects to identify
plausible phonon/vibration modes that inhibit theelectrical conduction at RT.

Ⅲ-2

Fig. 1 Far-infrared spectra of a pentacene single crystal
sample measured in a transmission configuration at
various temperatures (RT, 100 K, 40 K). Calculated
intramolecular vibrational modes using the ab-initio
density functional theory and lattice phonons ofpentacene single crystals taken from Ref. [1] are alsopresented.

[1] A. Girlando et al., J. Chem. Phys. 135 (2011) 084701.
[2] T. Sugiyama and Y. Furukawa, Jpn. J. Appl. Phys. 45(2007) 3537.

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Spectral Evidence of Current-Induced Local-to-Nonlocal Transition of SmS
H. Watanabe1,2, S. Tatsukawa2, K. Imura3, H. S. Suzuki4, N. K. Sato5 and S. Kimura1,2,6
Graduate School of Frontier Biosciences, Osaka University, Suita 565-0871, Japan
Department of Physics, Graduate School of Science, Osaka University, Toyonaka 560-0043, Japan3
Department of Physics, Graduate School of Science, Nagoya University, Nagoya 464-8602, Japan
4
Institute for Solid State Physics, The University of Tokyo, Kashiwa 277-8581, Japan
5
Aichi Institute of Technology, Toyota, 470-0392 Japan
6
Institute for Molecular Science, Okazaki 444-8585, Japan1

2

density could not be explained by the increase of lattice
temperature [5].
From these results, the current flow induces thedelocalization of electrons without increasing lattice
temperature. However, the golden-colored metallic
phase does not appear by the current. This result
suggests that the BGT needs other factors, such as
lattice deformation.

R (arb.units)

20

50K

(a)

15
10

0.0A
0.2A
0.6A
1.0A

5
30

R (arb.units)

Ⅲ-2

Samarium monosulfide SmS shows a pressureinduced insulator-to-metal transition from a blackcolored semiconductor to a golden-colored metal(BGT) [1,2]. Even though BGT was discovered morethan 50 years ago, its origin remains unclear. One
possible origin has been proposed as a transition
between the Bose-Einstein condensation (BEC) and the
BCS state of excitons [3], but no definitive evidence has
been obtained.
Recently, Ando et al. reported that the nonlinear
relationship between voltage (V) and electric current (I)occurs with increasing I at temperatures lower than 100
K, which suggests the electronic state changes byapplying current [4]. However, whether the currentinduced electronic state change is related to the BGT is
now under debate. To clarify the origin of the nonlinear
V/I curve and the link to the BGT, we investigate thecurrent and temperature dependence of the reflectivity
spectrum, which reflects electronic structure, in the nonlinear V/I region. We have already reported the rapid
increase of the effective carrier density at the nonlinear
V/I region by observing the THz reflectivity spectrum[5], which suggests the appearance of the currentinduced local-to-nonlocal transition of the electronic
structure. To clarify the whole picture of the currentinduced electronic structure change, we measured thecurrent dependence of the mid- and near-infrared
reflectivity spectrum using THz and IR microscopes at
BL6B.
The single crystalline SmS with a typical sample sizeof 1×1×1 mm3 was sandwiched by the electrodesconnected to the current source and mounted in a liquidhelium-cooled cryostat.
Figure 1 shows the I-dependent reflectivity spectra at
temperatures of 50 and 100 K. With increasing I, thereflectivity intensity below 0.1eV increases, suggesting
the carrier density increase. The peak at 0.6 eV
corresponds to the exciton peak of the direct bandgap at
the X point in the Brillouin zone [6,7]. The peak was
broadened and slightly shifted to the higher energy sidewith increasing I. The spectra at 50 K (a) and 100 K (b)qualitatively showed the same behavior. In the case of anormal insulator-to-metal transition, the bandgap size
decreases toward the metallic phase. However, thischange in Fig. 1 is the opposite of that expected. The
spectral shift is consistent with that with increasing
temperature [2]. Our THz reflectivity spectrum results
suggest that the current-induced increase of the carrier

25

0.4
0.8
Energy (eV)

1.2
100K

(b)

20
15

0.0A
0.2A
0.6A
1.0A

10
5

0.4
0.8
Energy (eV)

1.2

Fig. 1. Current dependence of mid- to near-infrared
reflectivity spectra of SmS at 50 K (a) and 100 K (b).
[1]A. Jayaraman et al., Phys. Rev. Lett. 25 (1970) 1430.
[2]T. Mizuno et al., J. Phys. Soc. Jpn. 77 (2008) 113704.
[3] B. I. Halperin and T. M. Rice, Rev. Mod. Phys. 40(1968) 755.
[4] H. Ando et al., JPS Conf. Proc. 30 (2020) 011132.
[5] H. Watanabe et.al., UVSOR Activity Report 2020
48 (2021) 81.
[6] S. Kimura et al., Physica B 403 (2008) 805.
[7]V. N. Antonov et al., Phys. Rev. B 66 (2002) 165208.

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BL6B

Structural Analysis of Fiber Biomaterials by Synchrotron-Radiation
Infrared Microspectroscopy
T. Kawasaki1, F. Teshima2 and K. Tanaka2

Accelerator Laboratory, High Energy Accelerator Research Organization, Tsukuba 305-0801, Japan
2
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan

1

Recently, fiber biomaterials such as cellulose fiberand peptide fiber have been getting attention in
medical and materials fields. The common feature in
their structures is a rigid sheet-like conformation, and
it is usually difficult to regulate the stacking format
without uses of extreme heating and organic solvents.
As an alternate approach, physical technique such as
high-power radiation can be proposed to control thefiber structure. Here, two-kinds of terahertz waves
were applied to regulate the cellulose fiber: one isterahertz free electron laser (THz-FEL) and the otheris submillimeter wave from gyrotron [1]. The THzFEL has a double pulse structure that is composed of
micropulse and macropulse where the duration of theformer is 10-20 ps and that of the latter is about 4 μs.
The oscillation wavelength covers from 30 to 300 μm,
and the irradiation power is given as avg. 5 mJ permacropulse. The submillimeter wave from the gyrotron
is a single pulse (1-2 ms half width) having 10 W power.
After the cellulose fiber was irradiated by the THz-FEL
that was tuned to 80 μm and the submillimeter wave thatwas tuned to 720 μm under atmospheric conditions atroom temperature, those samples were added on metalcoating plate and analyzed by using BL6B synchrotronradiation infrared microspectroscopy. The measurement
was performed by reflection mode with 64 scans.
In the FT-IR spectrum of cellulose (Fig. 1), strong
band at 1050 cm-1 and middle peak at about 1300 cm-1
were observed (Black). The former band corresponds
to stretching vibrational mode of glycoside bond (νCO), and the latter peak can be assigned to bending
vibrational mode of H-C-O, respectively [2]. After
THz-FEL irradiation (blue), the former peak wasdecreased and the latter peak was increased. On theother hand, the former peak was largely increased
accompanied by slight increase of the latter peak after
the submillimeter wave from gyrotron (red). These
spectral changes indicate that submillimeter wave
gave the irradiation effect on cellulose fiber opposite
to THz-FEL. Interestingly, when the cellulose fiber
was irradiated by submillimeter wave following THzFEL (green), the whole spectral pattern was almost thesame as that of the non-irradiation sample (black). One
interpretation on this phenomenon is that the cellulose
fiber was dissociated to the monomeric chain by the
THz-FEL irradiation, and the cellulose monomers werere-associated by the submillimeter wave radiation to
produce the original cellulose fiber.
We have ever found that amyloid fibrils that form
fiber structure like cellulose can be dissociated by the

THz-FEL and be promoted to form the aggregate by
the gyrotron. [3,4]. Therefore, it can be enoughconsidered that cellulose fiber can be dissociated andre-associated by those terahertz waves similarly withamyloid fibrils. The high-power terahertz waves canbe expected as a physical tool for regulation of thefiber biomaterials in future.

Fig. 1. Infrared spectra of cellulose fiber after
irradiation by terahertz waves. Black: non-irradiation;
blue: cellulose irradiated by THz-FEL; red: cellulose
irradiated by submillimeter wave from gyrotron; green:cellulose irradiated by submillimeter wave behind THzFEL.

[1] T. Kawasaki et al., J. Jpn. Soc. Infrared Science &Technology 31 (2022) 52.
[2] N. C. Carpita et al., Plant Physiol. 127 (2001) 551.
[3]T. Kawasaki, K. Tsukiyama and A. Irizawa, Sci. Rep.
9 (2019) 10636.
[4] T. Kawasaki et al., Biomed. Opt. Express 11 (2020)
5341.

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Ⅲ -2. Materials

BL7U

Low-energy ARPES Study of Iron-chalcogenide High-temperature
Superconductors
K. Nakayama1,2, T. Kato1, A. Moriya1, F. Nabeshima3, N. Shikama3, T. Ishikawa3, Y.
Sakishita3, S. Ideta4,5, K. Tanaka4,5, T. Takahashi1,6,7, A. Maeda3 and T. Sato1,6,7

1
Department of Physics, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency(JST), Tokyo 102-0076, Japan3
Department of Basic Science, University of Tokyo, Tokyo 153-8902, Japan
4
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
5
School of Physical Sciences, The Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan
6
Center for Spintronics Research Network, Tohoku University, Sendai 980-8577, Japan
7
Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, Sendai 980-8577, Japan2

Ⅲ-2

Since the discovery of high-temperature
superconductivity in LaFeAs(O,F), iron-based compounds
are attracting great attention. Among known iron-based
superconductors, iron selenide FeSe is the structurally
simplest material. It exhibits various exotic properties
such as anisotropic superconductivity and electronic
nematicity without long-range magnetic order. These
properties are sensitive to chemical substitution, highpressure application, and/or carrier doping. Therefore,
FeSe provides an opportunity to investigate the interplay
between nematicity and superconductivity while
controlling some physical parameters. In particular,
isovalent-substituted FeSe1-xTex and FeSe1-xSx films
offer an excellent platform. Nematicity is realized in
FeSe (x = 0) as in bulk FeSe, and the highest Tc of 23 K
among non-carrier-doped FeSe-based compounds has
been reported at the critical Te concentration xc of ~0.2
at ambient pressure [1]. On the other hand, for the Ssubstituted counterpart, large Tc enhancement is absent
and possible emergence of magnetism has been reported[2]. Comparative studies on these contrasting behaviors
would provide a key to understand the origin of exotic
properties.
In this study, we performed low-energy angleresolved photoemission spectroscopy (ARPES) studyof FeSe1-xTex and FeSe1-xSx films. High-quality thinfilms were grown by the pulsed laser deposition
method. ARPES measurements were performed usinga MBS-A1 spectrometer at BL7U in UVSOR withenergy-tunable photons of 12-25 eV.
Figures 1(a) and 1(b) show a comparison of the
ARPES intensity around the Brillouin-zone center
measured in pristine FeSe and FeSe1-xSx films,
respectively. In pristine FeSe, highly dispersive holeband with the dominant Fe 3dxz/yz orbital character (blue)
crosses the Fermi level (EF) and a relatively flat bandwith the Fe 3dxy orbital (red) is located well below EF.
On the other hand, Se/Te substitution leads to an upward
energy shift of the dxy band, resulting in the appearanceof the dxy-orbital character at EF. The large electronmass of the dxy band enhances the density of states at EF,
which is likely responsible for the Tc enhancement. We
also determined the evolution of the electronic structure

upon Se/S substitution, and compared the results withthose on FeSe1-xTex films to elucidate the mechanismsof nematicity and superconductivity as well as the originof contrasting phase diagram between FeSe1-xSx and
FeSe1-xTex.

Fig. 1. (a) and (b) ARPES intensity plotted as afunction of binding energy and wave vector measured
in FeSe and FeSe1-xTex films, respectively. Blue andred curves are a guide for the eyes to trace the dxz/yz anddxy band dispersions, respectively.

[1] Y. Imai et al., Sci. Rep. 7 (2017) 46653.
[2] F. Nabeshima et al., J. Phys. Soc. Jpn. 87 (2018)073704.

94 42 Ⅲ02-

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Ⅲ -2. Materials Sciences

BL7U

Elucidations of Electronic Structure and the Many-body Interactions ofOrganic Molecular Materials
K. Fukutani 1,2, Y. Hasegawa3, M. Murakami4, D. Okaue5, K. Fukui1,5, H. Ishii6,
K. Tanaka1,2 and S. Kera1,2,4
1
Institute for Molecular Science, Okazaki 444-8585, JapanThe Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan3
Department of Physical Sciences, Ritsumeikan University, Kusatsu 525-8577, Japan
4
Graduate School of Science and Engineering, Chiba University, Chiba 263-8522, Japan
5
Graduate School of Engineering Science, Osaka University, Toyonaka 560-8531, Japan
6
Department of Applied Physics, University of Tsukuba, Tsukuba 305-8573, Japan2

As the sustainability of our global resources andenergy-harvesting rapidly becomes a central issue innavigating our technological advancements, thedevelopment of quantum devices made of organic
molecular materials, characterized by their low
fabrication cost using abundant elements and high biodegradability, is of paramount importance.
Among such organic molecular materials, single
crystalline rubrene (C42H28) is known to exhibit
exceptionally high carrier mobility (40 cm2/Vs [1]) andis considered as a promising semiconductor material forthe next-generation electronics.
However, despite the numerous superiorities mentioned
above, what should be the most fundamental building
blocks for the future development are still incomplete;that is, the understanding of the electronic structure andtheir interactions with phonons and molecular vibrations.
For the purpose of elucidating these aspects of organic
materials, angle-resolved photoemission spectroscopy(ARPES) is a premier experimental technique, which
can simultaneously reveal the energies and momenta ofthe transport carriers (i.e., electrons and holes). Indeed,
ARPES has been extensively utilized for rubrene andunveiled, for instance, the existence of discernable band
dispersions for HOMO-derived bands [2], and the band
gap induced by the interactions of electrons withmolecular vibrations, revealed in our recent work [3].
On the other hand, there remain numerous criticalquestions about this material that are yet to be answered,including whether or not there are two HOMO-derived
bands (as theoretically predicted), and whether there
exists an interplay between the modes of molecularvibrations and the directions of electron propagation.
In our attempt to give the answers to these questions,
we have utilized the BL7U at UVSOR to perform thehigh-resolution ARPES experiments.
For elucidating the many-body interactions, we have
utilized the low photon energy of hv = 8.0 eV tomaximize the momentum resolution. From the data wehave obtained (see Fig. 1), we observe a discernabledifference in the magnitude of the band gap formed by
the electronic interaction with the intramolecularvibrations at different locations of the Brillouin zone.
This is likely a signature of anisotropy in the electronmolecular-vibration interactions in the rubrene crystal.

Further quantitative analyses are expected to give us thefirst opportunity to understand the interplay between themolecular vibrational modes and the direction of electron
propagations in molecular crystals
Furthermore, the ARPES data obtained at higher
photon energy (see Fig. 2) show two different HOMOderived bands which are degenerate at their maximum
binding energy. These are in agreement with thecalculated band structure and are expected to serve as a
key for resolving the long-standing discrepancy between
the theoretical predictions and experimental observations
in rubrene band structure.

Fig. 1. ARPES second derivative plots obtained for(a) kx = 0 Å-1 (Γ-Y line) and (b) kx = 0.14 Å-1.

Fig. 2. ARPES plots for two HOMO-derived bands
with (a, b) wider and (c) narrower dispersions. The
dashed curves in (b), (c) are visual guides.
[1]J. Takeya et al., Appl. Phys. Lett. 90 (2007) 102120.
[2] S. Machida et al., Phys. Rev. Lett. 104 (2010)
156401; H. Ding et al., Appl. Phys. Lett. 96 (2010)
222106; Y. Nakayama et al., Appl. Phys. Express 5(2012) 111601.
[3] F. Bussolotti et al., Nat. Commun. 8 (2017) 173.

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BL7U

Dirac-cone and Saddle-point Energy Bands in a Kagome Superconductor
AV3Sb5
K. Nakayama1,2, T. Kato1, Y. Li3,4, Z. Wang3,4, K. Tanaka5,6, T. Takahashi1,7,8, Y. Yao3,4
and T. Sato1,6,7

1
Department of Physics, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency(JST), Tokyo 102-0076, Japan
3
Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture andMeasurement (MOE), School of Physics, Beijing Institute of Technology, Beijing 100081, China
4
Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology,
Beijing 100081, China
5
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
6
School of Physical Sciences, The Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan
6
Center for Spintronics Research Network, Tohoku University, Sendai 980-8577, Japan
7
Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, Sendai 980-8577, Japan2

Ⅲ-2

Kagome lattice is an excellent playground to study
the physics intertwining electron correlation and nontrivial topology, owing to its peculiar band structure.
Theoretical studies on the kagome lattice predict theformation of nearly flat band, Dirac-cone band, andsaddle point van Hove singularity. When either ofthese bands is placed near the Fermi level (EF), various
unusual properties would be realized, e.g., Weyl
magnet, density wave orders, charge fractionalization,and superconductivity.
Recently, a new family of kagome-lattice materials
AV3Sb5 (A = K, Rb, and Cs) has been discovered. AV3Sb5
shows superconductivity with the superconducting
transition temperature Tc of 0.93–2.5 K, providing a rareopportunity to study superconducting properties in the
kagome lattice. AV3Sb5 also exhibits a charge-density
wave (CDW) transition at TCDW = 78–103 K, possibly
accompanied with time-reversal symmetry breaking. To
understand the origin of these exotic properties,
experimental investigations of electronic states are of
crucial importance [1].
In this study, we performed low-energy angleresolved photoemission spectroscopy (ARPES) studyof KV3Sb5 and studied the electronic states with a highmomentum resolution, which enables us to determine
momentum dependence of the CDW gap.
High-quality single crystals of KV3Sb5 were grownby the self-flux method. ARPES measurements were
performed by using a MBS-A1 spectrometer at BL7U
in UVSOR. Clean surfaces of the samples wereobtained by cleavage in an ultrahigh vacuum.
Figure 1 shows the ARPES intensity measured
along the ΓKM high-symmetry line of bulk hexagonal
Brillouin zone. One can identify an electron pocket
centered at the Γ point. This band is attributed to the
5p band of Sb atoms. One can also recognize linear
dispersions that produce multiple Dirac points near the
K point. These bands are attributed to the kagomelattice band with mainly V-3dxy character. One of the
Dirac-cone band (indicated by red arrow) shows aflattening with approaching the M point and forms asaddle-point dispersion. Upon decreasing thetemperature below TCDW, we found an opening of the
CDW gap on V-derived bands. Our detailed momentumdependent study demonstrates the largest gap opening
on the saddle-point band at the M point as well as theabsence of clear gap opening on the Sb-derived band.
Our observations suggest that the scattering between
the saddle-point bands and resultant large gap opening
stabilizes CDW, and Sb-derived parabolic band at theΓ point is likely responsible for the superconductivity
that coexists with CDW.

Fig. 1. ARPES intensity plotted as a function of binding
energy and wave vector measured in KV3Sb5.

[1] K. Nakayama et al., Phys. Rev. B 104 (2021)
L161112.

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BL7U

Angle-resolved Photoemission Study of TPP[FePc(CN)2]2
T. Ito1,2, T. Hoshina2, K. Tanaka3,4, M. Matsuda5 and N. Hanasaki6

Nagoya University Synchrotron radiation Research center (NUSR), Nagoya University, Nagoya 464-8603, Japan
2
Graduate School of Engineering, Nagoya University, Nagoya 464-8603, Japan
3
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
4
The Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan
5
Graduate School of Science and Technology, Kumamoto University, Kumamoto 860-8555, Japan
6
Department of Physics, Osaka University, Toyonaka 560-0043, Japan1

Molecular conductors are known to exhibit a variety
of properties ranging from magnetism tosuperconductivity, depending on the addition of
inorganic elements or the combination of cationic andanionic molecules. In particular, axially substituted metal
phthalocyanine (MPc, M = metal) molecules haveattracted attentions because of their unique physicalproperties such as a giant negative magnetoresistanceeffect [1]. Though their anomalous properties have been
expected to originate from strong π-d interactions, being
similar with those in strongly correlated transition metal,
the electronic structure of this system has never beenreported yet. In this study, we have investigated theelectronic structure of axially-substituted quasi-onedimensional(Q1D)
molecular
conductor
TPP[FePc(CN)2]2 single crystal by using angleresolved photoemission spectroscopy (ARPES).
ARPES measurements were performed at the
UVSOR-III BL7U. Data were acquired with hν = 40 eV
at T = 10 K. Measurement axis was set along 1D
conducting axis (//c). Needle-shaped single-crystals(typical size < 1 × 0.1 × 0.1 mm3) were cleaved in situ
along (110) plane. The relation between the cleavage
plane and conducting axis is shown in Fig. 1. To
minimize photoirradiation damage photon flux was
sufficiently reduced during all measurements.
Figure 2 shows valence band ARPES spectra of
TPP[FePc(CN)2]2 along the conducting axis. We havesuccessfully observed several peak structures (A-G)
from EF to 15 eV. Small background relative to peaks
suggests the cleanliness of the cleaved surface. Fromthe comparison of the ARPES spectra (Fig. 2) with thevalence band structure image (Fig. 3), peak B around
4 eV seems to show symmetric intensity reduction
together with sizable energy shift from Γ to Z point. In
addition, systematic energy shift has also beenrecognized around 5-7 eV (blue dashed lines). On theother hand, the energy shift of the peaks cannot be
observed at high-binding energy side (peaks E-G). We
expect that the observed change of ARPES spectra
originates from the energy dispersive feature on
TPP[FePc(CN)2]2.

Ⅲ-2

Fig. 1. Crystal structure of TPP[FePc(CN)2]2. Due tothe existence of the axial CN ligands, Pc units form a
one-dimensional chain along c axis, which corresponds
to π conducting axis.

Fig. 2. Valence band ARPES spectra along the ΓZline of TPP[FePc(CN)2]2. Blue and green dashed lines
are guide for dispersive and non-dispersive features.

Fig. 3. Valence band structure along the ΓZ line of
TPP[FePc(CN)2]2 .
[1] N. Hanasaki, et al., J. Phys. Soc. Jpn. 75 (2006)
033703.

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BL7U

Relationship between Chemical Pressure Effect and Electronic Structure in
R1-xCexOBiS2 (R=Nd, La)
1

Ⅲ-2

N. Kataoka1, T. Wakita1,3, Y. Hanada2, M. Nagao2 and T. Yokoya1,3

Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
2
University of Yamanashi, Kofu 400-8511, Japan
3
Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan

BiCh2 compounds are quasi-two-dimensional materials
with a layered structure typically represented by thecomposition of RO1-xFxBiCh2 (R=rare earth; Ch= S,
Se). It can be doped electrons by replacing oxygen withfluorine atoms or by introducing mixed valence R atoms
such as Ce and Eu into R sites. Electron-doped samples
show superconductivity below 2-10 K. Several
experimental and theoretical studies have indicated thepossibility of unconventional superconducting
mechanisms [1]. Since the superconducting transition
temperature (Tc) is sensitive to the pressure applied to
the BiCh2 planes, the chemical pressure effects of many
elemental substitutions have been intensively studied[1-3]. The chemical pressure effects are important forunderstanding the superconducting mechanism, although
there are few systematic reports on the electronic
structure. In R1-xCexOBiS2, the ratio of Ce4+ at the R site
is about 0.1~0.15 despite the composition, so theaverage ionic radius of the R site can be controlled while
keeping the electron doping level fixed [2,3]. Therefore,
it is the best material for investigating the relationshipbetween pressure and electronic structure in the BiCh2
systems. In this study, angle-resolved photoemission
spectroscopy (ARPES) measurements of R1-xCexOBiS2
were performed to investigate the relationship between
pressure and the electronic structure.
The measurements were performed using R1-x
CexOBiS2 (R=La, Nd; x=0.2~0.75) single crystals
synthesized by the flux method [2,3]. ARPES
measurements were performed at BL7U of UVSOR III,using 20 eV photons with an energy resolution of 15~20
meV. All samples were cleaved in situ on the (001)plane in an ultrahigh vacuum of less than 5×10-9 Pa.
Figures 1 (a) and (b) show the Fermi surfaces of
Nd0.7Ce0.3OBiS2 and La0.75Ce0.25OBiS2, respectively,and (c) and (d) show the respective band dispersions.
Nd0.7Ce0.3OBiS2 is a superconductor with Tc of ~5K,
while La0.75Ce0.25OBiS2 is non-superconductive at least
above 1.5K. Nd0.7Ce0.3OBiS2 and La0.75Ce0.25OBiS2
have inner and outer electron pockets, respectively,
centered at the X point. Nd0.7Ce0.3OBiS2 is a relatively
low-dimensional Fermi surface, with nested quadrilateralFermi surfaces on both the inner and outer sides. On
the other hand, La0.75Ce0.25OBiS2 has an inner Fermi
surface distorted into an elliptical shape extending inthe Γ-X direction (perpendicular to X-M-X direction).
The outer Fermi surface also seems to be distorted.
The difference in the shape of the Fermi surface may be,
to a first approximation, due to differences in electron

doping levels rather than chemical pressure. In fact, thesizes of the Fermi surfaces are different and there is adifference of about 0.1 eV in the energy at the bottom of
the band. Furthermore, their Fermi surface shapes are
similar for n = 0.125 and n = 0.25 electron doping levels[4]. In this regard, it may be possible here that the nested
Fermi surfaces are more favorable for achieving higher
superconducting transition temperatures, given that
Nd0.7Ce0.3OBiS2 has a higher superconducting transition
temperature. For a more comprehensive understanding,comparisons with other compositions of the material
should be made.

Fig. 1 (a) and (b) Fermi surfaces, as well as (c) and (d)band dispersions along X-M lines, for Nd0.7Ce0.3OBiS2
and La0.75Ce0.25OBiS2, respectively.

[1] Y. Mizuguchi J. Phys. Soc. Jpn. 88 (2019) 041001.
[2]Y. Hanada et al., Jpn. J. Appl. Phys. 58 (2019) 063001.
[3] Y. Fujita et al., ACS Omega 5 (2020) 16819.
[4] M. Ochi et al., J. Phys. Soc. Jpn. 85 (2016) 094705.

98 46 Ⅲ02-

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BL7B

Photoluminescence Properties of Cs2ZnCl4 and Cs3ZnCl5 with Vacuum
Ultraviolet Excitation
K. Takahashi, M. Koshimizu, Y. Fujimoto and K. Asai

Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan

Auger-free luminescence (AFL) is owing to theradiative transition between the valence band and theoutermost core level. Generally, AFL is not efficientbecause the transition is competitive with the Auger
process, which is generally a much faster process thanthat of AFL. In other words, efficient AFL has been
observed in limited compounds such as alkaline- or
alkaline-earth fluorides or CsCl-based compounds.
In recent years, we have developed fast scintillators
exhibiting AFL on the basis of ternary CsCl-based
compounds, such as Cs2ZnCl4 [1], CsCaCl3 [2], andCs2BaCl4 [3]. Fast scintillation decay within 2 ns has
been achieved. The scintillation light yields of thesecompounds were less than 1,500 photons/MeV, which
is significantly smaller than those of Ce-doped
inorganic scintillators. Hence, we further investigatednovel compounds based on CsCl. As an example of thefurther investigation, we have recently reported thephotoluminescence and scintillation properties of
Cs3ZnCl5 in comparison to those of Cs2ZnCl4 [4]. In
the present report, we present the excitation spectra ofCs2ZnCl4 and Cs3ZnCl5, which clearly indicates thatthe emission was attributed to AFL.
Crystalline samples of Cs2ZnCl4 and Cs3ZnCl5 wereused for the measurements. The measurements of thephotoluminescence under irradiation with vacuum
ultraviolet light were performed at BL7B of UVSOR atroom temperature. The excitation wavelength between
50 to 200 nm was used for the measurements. The
photoluminescence from the samples were observedwith a CCD-based spectrometer via an optical fiber. The
photoluminescence spectra with different excitation
wavelengths were recorded. On the basis of thephotoluminescence spectra, the excitation spectra wereobtained.
To verify the origins of the emission bands at 260
and 310 nm of Cs2ZnCl4 and 240 and 290 nm of
Cs3ZnCl5 crystals, we obtained the excitation spectra
monitoring the wavelengths. Figures 1 and 2 present
the excitation spectra. The excitation spectra ofCs2ZnCl4 are well consistent with those in a previous
report [1]. A steep rise was observed in both excitation
spectra at around 90 nm, which corresponds to theexcitation of electrons at the outermost core level tothe conduction band. Hence, based on the excitation
spectra, the emission bands are attributed to AFL.

Ⅲ-2

Fig. 1. Excitation spectra of Cs2ZnCl4 for monitored
wavelengths of 260 and 310 nm [4]. Copyright (2020)
The Japan Society of Applied Physics.

Fig. 2. Excitation spectra of Cs3ZnCl5 for monitored
wavelengths of 240 and 290 nm [4]. Copyright (2020)
The Japan Society of Applied Physics.

[1] N. Yahaba, M. Koshimizu, Y. Sun, T. Yanagida, Y.
Fujimoto, R. Haruki, F. Nishikido, S. Kishimoto, andK. Asai, Appl. Phys. Express 7 (2014) 062602.
[2] M. Koshimizu, N. Yahaba, R. Haruki, F. Nishikido,
S. Kishimoto, and K. Asai, Opt. Mater. 36 (2014) 1930.
[3]K. Takahashi, M. Arai, M. Koshimizu, Y. Fujimoto,T. Yanagida, and K. Asai, Jpn. J. Appl. Phys. 59 (2020)
032003.
[4] K. Takahashi, M. Arai, M. Koshimizu, Y. Fujimoto,T. Yanagida, and K. Asai, Jpn. J. Appl. Phys. 59 (2020)
072002.

99 47 Ⅲ02-

BL7B Sciences
Ⅲ -2. Materials

BL7B

Investigation of Gamma-ray-irradiated Oxide Glasses for Deep Ultraviolet
Detector with High Efficiency
T. Shimizu, K. Shinohara, D. Umeno, K. Yamanoi and N. SarukuraInstitute of Laser Engineering, Osaka University, Suita 565-0875 Japan

Ⅲ-2

Vacuum ultraviolet (VUV) light is used in important
technological applications such as photochemical
processing, surface treatment, optical cleaning ofsemiconductor substrates, and sterilization. In particular,
it has been suggested that non-contact sterilization,
treatment, and processing could be advanced by using
VUV in the current corona disaster. For such recent
progress in VUV research and applications, it isnecessary to develop detectors in the short wavelength
range. In the development of VUV detectors, it isimportant to evaluate spectral characteristics in VUVregion.
Previously, we have studied fluoride crystals, suchas MgF2 and CaF2, for VUV optical devices [1,2].
Fluoride crystals are widely used in ultraviolet (UV)
optics because of their wide band gaps. And also wehave investigated fluoride glasses for VUV opticaldevices [3].
In addition, there are high expectations for material
modification by gamma-ray irradiation. We haveinvestigated the improvement of time resolution of
scintillators such as ZnO by gamma-ray irradiation.
Gamma-ray irradiation can be used as a post-processing
step and is expected to improve the performance ofvarious devices.
In our recent study, gamma-ray induced opticalproperty changes in non-doped and Ce-doped lithiumrich oxide glasses are investigated [4]. However, opticalproperties of these material in VUV region has not been
fully researched. Neutron measurements are importantin fusion experiments, and lithium-rich oxide glasses
are used as scintillator to detect neutrons. Evaluation of
VUV characteristics of scintillator material is important
to improve the performance of neutron detection. Inhigh dose rate environment such as nuclear fusion
experiment, optical materials are easily damaged. It isreported that Ce doping in the base material preventsdegradation of optical materials.
In this study, we measured transmittance of gammaray-irradiated oxide glasses from VUV to visible region.
We used a lithium borosilicate glass (LBS) and CeF3doped LBS. All glass samples were fabricated by themelt-quenching method [4]. To fabricate LBS, a
mixture of high purity 99.99% boric acid (H3BO3), highpurity silica (SiO2) and lithium carbonate (Li2CO3) was
melted at 1100 °C for 2 h under air atmosphere. Natural
Li was used for all sample fabrication. The melted glass
was quenched in air in a graphite mold and thenannealed at 500 °C for 3 h. The CeF3-LBS glasses were
fabricated using similar precursors with the addition of
CeF3 powder. Precursors for Ce-doped samples weremelted in an aluminum crucible for 3 h at 1200 °C andwere quenched in air in a graphite mold, then subsequently
annealed at 350 °C for 3 h. After fabrication, the nondoped glass samples were cut and polished into 10 mm
× 10 mm flat plates with thicknesses ranging from 3.8
mm to 4.2 mm. The Ce-doped samples were cut andpolished into 15 mm × 10 mm, with thickness ranging
from 3.1 mm to 3.8 mm. The glass samples were
irradiated with gamma rays carrying 1.17 and 1.33 MeV
energies from a cobalt-60 (60Co) source. The 60Co
source was calibrated with water and had a dose rate of
36.82 Gy/h at a distance of 1.0 m. The samples were set
approximately 10 cm away from the radiation source.
The irradiation was performed at room temperature andin ambient atmosphere.
Figure 1 shows measured transmittance of gammaray-irradiated LBS and CeF3-LBS. In both samples,high transmittance was measured even with VUV.
Although Ce was not seen to have much of an effect inthis measurement, it is expected to reduce the effect of
gamma irradiation.
In the future, we will compare more detailed
conditions and develop materials for high-efficiency
deep-ultraviolet photodetectors.

Fig. 1. Transmittance of gamma-ray-irradiated oxide
glasses.

[1] T. Shimizu et al., UVSOR Activity Report 47(2019) 107.
[2] K. Yamanoi et al., Opt. Mater. 36 (2014)769.
[3] T. Shimizu et al., UVSOR Activity Report 2020 48(2021) 88.
[4] Y. Lai et al., Radiat. Phys. Chem. 179 (2021)
109272.

10048 Ⅲ02-

UVSOR User 4

UVSOR User 5

Ⅲ-3
Chemistry
ChemistryBL3UⅢ -3. Chemistry

BL3U

Solvent-Induced Transition of Polymorphological Chiral SupermolecularArchitectures in Bent-Core Liquid Crystal Dimer/Nematic Binary Mixtures
as Studied by Resonant Soft X-ray Scattering (RSoXS) at UVSOR
F. Araoka1, Y. Takanishi2, K. V. Le3 and H. Iwayama4,5

RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
2
Faculty of Science, Kyoto University, Kyoto 606-8502, Japan
3
Faculty of Science, Tokyo University of Science, Tokyo 162-8601, Japan
4
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
5
School of Physical Sciences, The Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan1

Nano-scaled chiral superstructures, such as tilted
lamellar (smectic) structures or helical nanofilaments(HNFs), are often observed in polar (or apolar) softmesophases of achiral bent-core molecules, although
their chemical structure has no chiral carbon. The socalled B4 phase is one of such soft-mesophases, inwhich chirality is macroscopically recognizable as
millimeter-sized domains optically segregated under apolarizing microscope. There are two types of B4
domains resembling each other, originated from two
different nanoscopic structures; One is filled withbundles of polar HNFs with a pitch of several tens tohundreds nm, and the other is the so-called dark
conglomerate (DC) in which concentric polar lamellar
structures are interconnected to form bicontinuous
pores like a sponge. However, in both cases, the polartilted lamellar structure is essential and thus almost
identical diffraction patterns are obtained byconventional small angle X-ray scattering (SAXS).
Recently, we discovered that these two structures areinterchangeable by adding a nematic solvent (ZLI-2293,
Merck) to the host bent-core molecule (12OAz5AzO12).
Besides, further addition of the nematic solvent induced
an unprecedented nano-tubular structure like a “macaroni”
as a novel chiral state. This nanoscopic morphologicalchange was first confirmed with scanning electron
microscopy (SEM, Fig. 1) – the result suggests thatphase separation reduces interfacial free energy andcreates spaces to allow the lamellar to be more twisted,leading to the structural transition from DC to macaroni
via HNF. However, the SEM technique requires vacuum
for electrons to fly, and thus the samples were fractured
to expose the internal structure and washed with Hexane
to completely remove the solvent nematic molecule.
This leaves uncertainty if the bulk structures are surely
preserved during the fracturing/washing process or not.
Meanwhile, HNF/DC are just morphologicallycharacterized, and hence electron density is basicallynot spatially modulated by these structures. This meansthat usual X-ray diffraction/scattering is not very useful
to investigate the present system. For these reasons, we
performed resonant soft X-ray scattering (RSoXS)
measurements using X-ray whose energy is close to thecarbon K-edge absorption, which allows us to analyze
the nanoscopic structural change in such amorphologically transformable system.

Our RSoXS setup was prepared in BL3U of UVSOR
at IMS – A homemade vacuum chamber equipped with acooled CCD camera (Newton, Andor) was newly
designed for small angle detection (2θ~1-15°). In thepresent study, the X-ray photon energy was chosen as
284.5 eV, corresponding to the carbon K-edge absorptionof the present sample mixtures.
RSoXS patterns for HNF, DC and Macaroni arecompared in Fig. 2, which clearly shows transitions dueto the morphological change among these states. HNFs,
appearing in the middle doping range, show relatively
sharp scattering patterns at the scattering angle
corresponding to the half-pitch periodicity of the twisting
filaments. On the other hand, DCs show broad peaks at
the slightly smaller scattering angle region than HNFs,
which would be corresponding to the average distances
between the lamellar inter-connections. Interestingly,
the macaroni state shows just scarce signals in thisregion, meaning almost no nanoscopic structural
periodicity. Needless to say, these confirm that thepresent RSoXS setup works well for structuralinvestigation for such soft-mesophases.

Fig. 1. Nanoscopic morphological transformation
among DC, HNF, and macaroni as observed by SEM.

Fig. 2. RSoXS pattern alteration corresponding to thenanoscopic morphological transformation.

105 1 Ⅲ03-

Ⅲ-3

BL1U
Ⅲ -3. Chemistry

BL1U

Energy-Dependence of Photoelectron Circular Dichroism of Chiral Molecules
H. Kohguchi1, Y. Hikosaka2, T Kaneyasu3, S. Wada1, H. Ohta4, M. Fujimoto4, M. Katoh4
and Y-I. Suzuki5
Graduate School of Advanced Science and Engineering, Hiroshima University,
Higashi-Hiroshima 739-8526, Japan
2
Institute of Liberal Arts and Sciences, University of Toyama, Toyama 930-0194, Japan
3
SAGA Light Source, Tosu 841-0005, Japan
4
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
5
School of Medical Technology, Health Sciences University of Hokkaido, Tobetsu 061-0293, Japan1

Ⅲ-3

A simple explanation of the manifestation ofphotoelectron circular dichroism (PECD), which ismeasured as forward-backward asymmetry of thephotoelectron angular distribution with circularly
polarized light, can be that the outgoing photoelectron
is affected by a chiral potential originated from thechiral core ion. The intuitive model indicates that theslower photoelectron can exhibit the larger PECD.
Actually, most of the PECD measurements so far
carried out for various chiral molecules demonstrated
decreasing PECD parameters (b1) as the higher photon
energies. However, the b1 parameters of the individual
electronic states varied in an independent manner,
showing the state-specificity. The energy-dependence
and state-dependence of PECD are not simply
understood with a simple model but should be
examined based on the precise measurements andaccurate theoretical calculations, both of which canprovide novel pictures for the PECD mechanism.
We have conducted the PECD measurements for S
methyl oxirane and other chiral molecules with
employment of circular polarized light at BL1U atvaried photon energies [1]. Methyl oxirane (propyleneoxide) is a typical chiral molecule, whose PECD has
been intensively studied. Our results are shown in Fig.
1, where the photon energy-dependence is shown in aseries of the image data for (a) 10.3 eV, (b) 11.0 eV, (c)12.0 eV, (d) 12.7 eV, (e) 13.3 eV, and (f) photoelectron
kinetic energy (PKE) scale. Distinct ring structures
corresponding to individual electronic states appearedat the higher photon energy than (a) 10.3 eV (close to
the ionization threshold) with particular PECD, whose
positive and negative b1 values are represented by red
and blue colors. The b1 value of each ring decreases as
the elevated photon energy, but the decreasing
behaviors were not monotonic but rather dependent on
the states. The strongest PECD observed in the 2 eV
PKE region at (c) hν = 12.0 eV rapidly disappeared at
an only slightly larger photon energy of (d) hν = 12.7
eV, while other bands kept the contrast of the blue/redcolor (b1 PECD parameter) for the wider photon
energy variations.
The present results are qualitatively similar to theprevious study of methyl oxirane [2]: the sign of the b1
parameters of the three electronic states were well
reproduced. We extended our measurements for thefiner intervals of the photon energy to examine theenergy-dependence of PECD. A faint feature of thesign change of PECD with the varied photon energy
was found in the second band, which is more visible in
the polar representation of the observed results (Fig. 1.
lower). These results will be verified in comparison
with theoretical calculations.
Raw Images of PECD

Polar Plot Images of PECD

Fig. 1. (Upper) Difference images of photoelectron
scattering with left-hand and right-hand circularly
polarizations and (Lower) the polar plot presentationsof PECD of S-methyl oxirane at varied photon
energies.
[1] H. Kohguchi, Y. Hikosaka, T Kaneyasu, S. Wadaand Y-I. Suzuki, UVSOR Activity Report 2019 47(2020) 107.
[2] G. A. Garcia, H. Dossmann, L. Nahon, S. Daly and
I. Powis, Phys. Chem. Chem. Phys. 16 (2014) 16214.

106 2 Ⅲ03-

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Ⅲ -3. Chemistry

BL1U

Photoionization of Atoms by Double-pulsed Radiation from a TandemUndulator
T. Kaneyasu1, Y. Hikosaka2, S. Wada3, M. Fujimoto4,5, H. Ota4, H. Iwayama4,5and M. Katoh6,4

1
SAGA Light Source, Tosu 841-0005, Japan
Institute of Liberal Arts and Sciences, University of Toyama, Toyama 930-0194, Japan
3
Graduate School of Advanced Science and Engineering, Hiroshima University,
Higashi-Hiroshima 739-8526, Japan
4
Institute for Molecular Science, Okazaki 444-8585, Japan
5
The Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan
6
Hiroshima Synchrotron Radiation Center, Hiroshima University, Higashi-Hiroshima 739-0046, Japan
2

Recently, we have shown a new ability of a tandemundulator in a synchrotron to perform wave packet
interferometry using double-pulsed light wave packets.
This has enabled the quantum manipulation of theatomic system, so-called coherent control, by synchrotron
radiation. The potential of this method has been
demonstrated in the proof-of-principle experiments on
gas-phase atoms [1-3]. In these experiments, we used adouble-pulsed light wave packet to produce a pair ofelectron wave packets (superposition of eigenstates) thatinterfere in the single atom. The quantum phasedifference between the interfering electron wave packets
determines the behavior of the quantum state to becontrolled or probed, and is precisely controlled byvarying the time delay between the double-pulsed
components of light wave packet in the attosecond level.
Here, we extend this approach to the electron wave
packets produced in an ionization continuum. The
experiment was carried out at the undulator beamline
BL1U. The double-pulsed light wave packet was
generated by a tandem-undulator in the synchrotron
ring. The waveform of the light wave packet wascharacterized by time-separated 10-cycle oscillations.
The fundamental radiation wavelength was set to ~40
nm. The double-pulsed light wave packet interactedwith a helium atom, leading to the production of a pairof photoelectron wave packets that interfere in freespace. To verify the interference between the photoelectron
wave packets, we measured a photoelectron spectrum
using a hemispherical electron analyzer fixed at anangle of 55° with respect to the polarization axis.
Figure 1 compares the photoelectron spectra measured
for the radiation from a single undulator (a and b) andtandem-undulator (c and d) configuration. The
photoelectron spectra in a and b show single peaked
distributions centered at around 5 eV. This spectral
shape simply reflects the spectral distribution of theradiation from the single undulator which is characterized
by a Gaussian-like distribution with 10 % width of thecentral photon energy. In contrast, the photoelectron
spectra show clear interference patterns when thetandem undulator is used to ionize the helium atoms.
Moreover, the spacing between interfering fringes

depends on the time separation between the doublepulsed components of the light wave packet. To interpretthe experimentally measured data, we have calculated
the photoelectron spectrum (not shown here), and agood agreement between the experimental andcalculation results is obtained. Therefore, it is reasonable
to conclude that we observed the interference between
the photoelectron wave packets in the present study.

Fig. 1. Photoelectron spectra of helium atoms measured
by using radiation from (a) upstream undulator, (b)downstream undulator, (c) and (d) tandem undulator.
The time delays between the double-pulsed componentsof light wave packet are (c) 2 fs and (d) 4.5 fs.

[1] Y. Hikosaka et al., Nat. Commun. 10 (2019) 4988;
ibid. 12 (2021) 3782.
[2] T. Kaneyasu et al., Phys. Rev. Lett. 123 (2019)
233401.
[3] T. Kaneyasu et al., Phys. Rev. Lett. 126 (2021)
113202.

107 3 Ⅲ03-

Ⅲ-3

BL2B
Ⅲ -3. Chemistry

BL2B

Electronic State Changes of Cu Nanoparticles on Rutile TiO2(110) by
CO Exposure
1

Ⅲ-3

K. Mitsuhara1, K. Ide2, H. Takatani2, Y. Hasegawa2 and M. Takizawa2

Ritsumeikan Global Innovation Research Organization, Ritsumeikan University, Kusatsu 525-8577, Japan2
Department of Physical Science, Faculty of Science and Engineering, Ritsumeikan University,
Kusatsu 525-8577, JapanFor Cu based catalysts, it exhibits strong catalytic
activities for the carbon monoxide oxidation, water-gas
shift reaction, methanol oxidation and others [1].
However, their performance is not fully understood. In
previous study, we have found the growth mode of Cu
nanoparticles deposited on the rutile TiO2(110) surfaces
by medium energy ion scattering (MEIS) [2]. As a result,
the two-dimensional (2D) islands grow initially up to Cu
coverage of ~0.5 ML and then the three-dimensional(3D) island-growth becomes dominant. The electronic
state of supported metal particles is also known to playa critical role in determining catalytic activity.
Understanding the adsorbate-induced changes in thesurface electronic state is therefore important. In thisstudy, we manifest the reaction of Cu nanoparticles
supported rutile TiO2(110) with carbon monoxide byphotoelectron and photon-induced secondary electrons
emission spectroscopy.
The experiment was performed at beamline BL2B of
the UVSOR synchrotron factory at the Institute for
Molecular Science. We prepared the oxygen-rich rutileTiO2(110) surfaces (O-TiO2) by exposure of O2 (5 N)
onto the reduced surfaces (R-TiO2), which were formedby sputtering with 0.75 keV Ar+ followed by annealing
at 870 K for 10 min in UHV. Cu was deposited on theclean surfaces at RT with a Knudsen cell at a rate of 0.08
ML/min under UHV condition. Here, 1 ML means
1.77×1015 atoms/cm2, corresponding to the areal densityof Cu(111).
Figure 1 (a) shows secondary electron spectra taken forCu(0.2 ML)/O-TiO2(110) and oxidized Cu(0.2 ML)/OTiO2(110) before and after CO exposure, respectively.
After O2 exposure of 500 L, the work function increases.
This electronic state changes indicate an upward band
bending. The mechanism of this upward band bending
may be considered as follows: Cu nanoparticles areoxidized to Cu2O by oxygen exposure and then the
upward band bending is caused by a p-n junction
between Cu2O and TiO2 substrate. After CO exposure of
15,000 L, the work function slightly decreased, whilethe valence band spectra and Ti 3p and O 2s lines did
not change nor shift significantly (not shown). Thechange in work function showed the same tendency
even for Cu coverage of 1.0 ML [see Fig.1 (b)]. The
work function of TiO2(110) surfaces scatter largely
owing to strong dependence upon bulk and surface
defect densities. Note that work function consists ofbulk and surface dipole terms and the surface term
originates from a surface dipole consisting of positive

cores and valence electrons near a surface. Therefore, thisresult is ascribed to elimination of the electronegative
adsorbate oxygen on top of the surface resulting in
weakening the surface dipole with a negative polarity on
the vacuum side. These results may suggest that
presence of Cu nanoparticles on O-TiO2(110) strongly
enhances the reaction between O and CO.
(a)

(b)

Fig. 1 Secondary electron spectra taken for (a) Cu(0.2ML)/O-TiO2(110) and (b) Cu(1.0 ML)/O-TiO2(110)before and after CO expos[1] J. M. Thomas et al., Principles and Practice ofHeterogeneous Catalysis, VCH, New York, 1997.
[2] T. Aoki et al., e-J. Surf. Sci. Nanotechnol. 16 (2018)225.

108 4 Ⅲ03-

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Ⅲ -3. Chemistry

BL3U

X-ray Absorption Spectra of Aqueous Cellobiose
T. Sasaki and D. Akazawa

Department of Complexity Science and Engineering, Graduate School of Frontier Sciences, The University of Tokyo,
Kashiwa 277-8561, Japan
Biomass conversion using water or an ionic liquid asa solvent without using an organic solvent is an
important research topic. There have been many studies
on biomass-related compounds in solution, but there are
few reports on their molecular theory. We have studied
the conversion process by dehydration reaction ofpolyalcohol as models of sugar molecules and foundthat the solvation structure with water molecules and theinteraction with protons are important for the reaction
process [1,2].
The purpose of this study is to explore the solvation
structure of sugar molecules in aqueous solution, which
is important in the conversion process from cellobiose
to glucose, that is typical of biomass-derived sugar
alcohol conversion using water or ionic liquids.
Cellobiose, a disaccharide, is taken up as a model
substance for cellulose, which is one of the starting
materials in biomass conversion.
XAS measurements for liquid samples wereconducted at UVSOR BL3U using facilities developed
by Nagasaka et al. [3]. The liquid sample cell with
Si3N4 membranes was adopted, where the thickness of
the liquid layer was controlled by the He gas pressurearound the cell.
Figure 1 shows C-K edge XAS spectra for cellobiose
aqueous solutions with concentrations specified in the
figure. Fig. 2 shows O-K edge XAS spectra for cellobiose
aqueous solutions as well as the spectrum for water (0M). Molecular dynamics calculations for the solutions
and the XAS simulations were conducted using CP2K
program to interpret the XAS spectra.
In Fig. 1 three peaks were observed at 289.3, 290.7
and 293.6 eV, named as “A”, “B”, and “C”, respectively.
A peak at 290.0 eV was defined as “A”, which does notappear for the aqueous solution but is expected to appear
in the gaseous isolated cellobiose molecule as found by
MD and XAS simulation. With the XAS simulation it
was concluded that A, B and C correspond to theabsorption by carbon atoms of the alcohol group, thehemiacetal group and the both of these groups,
respectively. Temperature and concentration dependences
of XAS spectra for cellobise aqueous solutions were
measured and relative intensity change of three peaks
were observed, which can be explained by the change in
the number of hydrogen bond between cellobiose andwater. These results were published recently [4]. The
analysis of O-K XAS spectra for cellobiose aqueous
solutions is under way.

Ⅲ-3
Fig. 1. C-K XAS spectra for cellobiose aqueous
solutions at 25 °C. Blue : 0.20 M, Green : 0.15 M.

Fig. 2. O-K XAS spectra for cellobiose aqueous
solutions at 25°C. Blue : 0 M, Purple : 0.20 M, Green :0.05 M.

[1]Y.L. Chang et al., J. Phys. Chem. B. 123 (2019) 1662.
[2] T. Kondo et al., J. Compuational Chem. 42 (2021)
156.
[3] M. Nagasaka et al., J. Electrosc. Relat. Phenom. 200(2015) 293.
[4] D. Akazawa et al., J. Chem. Phys. 156 (2022) 044202.

109 5 Ⅲ03-

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Ⅲ -3. Chemistry

BL3U

X-ray Absorption Spectroscopy Study of 4-MBA on Gold Surfaces
1

Ⅲ-3

I. Sakaida1, S. Ohno1, M. Nagasaka2

Graduate School of Engineering Science, Yokohama National University, Yokohama 240-8501, Japan
2
Institute for Molecular Science, Okazaki 444-8585, Japan

It is important to understand the behavior of
biomolecules on solid surfaces for the application to
medical device, biosensor and biocompatible material.
It is essential to study the adsorption and desorption
behavior of molecules and their response to the appliedfields. It is of particular importance to analyze thedynamic behavior of biomolecules on surface inelectrolyte solutions close to the realistic condition in
the body of living creatures [1,2]. However, the numberof studies appears to be still quite limited, especially forthe investigation of the dependence of the molecularorientation and ionization on the electrolyte solutions.
In this study, potential-dependent adsorption/desorption
behavior of 4-mercaptobenzoic acid (4-MBA) on Au(111)and Au membrane surfaces have been investigatedusing soft X-ray absorption spectroscopy (XAS) in the
fluorescence yield mode for the former case, and in thetransmission mode in the latter case. The experiments
were performed on the soft X-ray undulator beam line at
UVSOR-III, BL3U. We used NaClO4 as the electrolyte
solution. For the adsorption of 4-MBA molecules, thesamples were immersed in 1mM 4-MBA/ethanol
solution for more than 30 min.
In our previous study, we have studied theadsorption/desorption behavior of 4-MBA on Au films
using surface differential reflectance spectroscopy(SDRS) combined with cyclic voltammetry (CV) [3].
The key issue was the interaction between functionalgroup (-COOH) and Au films through Coulombinteraction depending on the applied biases and pH
conditions. Redox processes involving charge transfer
were clearly observed CV and the relation between thechange in the reflectance spectra were investigated indetail. Interestingly, we found some precursor
phenomena to cause significant changes in thereflectance spectra with no corresponding signal in thecyclic voltammogram. This indicates that the suchchanges in the reflectance spectra are not related to thecharge-transfer-type reactions but rather to the subtle
change in the orientation/conformation of 4-MBA
molecules.
To our knowledge, there has been no serious effort tostudy the 4-MBA/Au system using XAS. We, therefore,
tried to investigate the possible precursor phenomena
addressed above. Firstly, we have tried to observe theeffects on Au(111). However, we could not obtain theclear data showing the adsorption/desorption behaviorof 4-MBA. This could be understood because of therelatively low signal-to-noise ratio in the fluorescence
yield mode, and the amount of the adsorbed 4-MBA
might be less than the detection limit. In order toimprove the surface sensitivity, we next tried to observe

the effects on membrane Au surface.
Our preliminary results showed clear spectralfeatures in the O K-edge region, as shown in Fig. 1.
One is due to the π* component assigned to the C=O
double bond, and the other is possibly due to theformation of the hydrogen bond. The investigation of
the C K-edge region is underway.
The next step should be the observation of the slighteffects due to the change in the orientation/conformation
depending on the applied bias to the electrode (Aumembrane). Obviously, we have to conduct the surfacesensitive measurements further to elucidate such subtle
effects.
It should be noted that more distinct change in the
XAS spectra can be envisioned in the case of cysteine
molecules, for which two of them can attach to form acystine molecule [3]. At this point, we have establishedthe measurement set up for the transmission mode.
Therefore, we now also plan to re-investigate thereactions of biomolecules, in terms of the ionization of
the functional groups (-COOH, -NH3).

Fig. 1. O K-edge XAS spectrum for 4-MB.

[1] R. LeParc et al., Langmuir 22 (2006) 3413.
[2] C. I. Smith et al., J. Electrochem. Soc. 150 (2003) 1.
[3] N. Ikeda et al., ALC’19, AP-52 (2019) 22.

110 6 Ⅲ03-

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BL3U

Resonant Soft X-ray Scattering Equipment Evaluated by Chicken Leg’s
Collagens and 100-nm Silica Nanoparticles
H. Iwayama1,2, F. Araoka3 and Y. Takanishi4

UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
School of Physical Sciences, The Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan
3
RIKEN Center for Emergent Matter Science, Wako 351-0198, Japan
4
Faculty of Science, Kyoto University, Kyoto 606-8502, Japan
1

2

Resonant Soft X-ray Scattering (RSoXS) is similar to
Small Angle X-ray Scattering (SAXS) and can provide
information on the mesoscopic structure (1 ~ 100 nm) of
samples. Due to the resonance process, RSoXS haveselectivities of elements, functional groups and molecularorientations. In particular, since soft x-ray region include
K-edge energies of light element such as carbon, nitrogenand oxygen, RSoXS will be a powerful tool to investigate
soft matter, which mainly consists on light element atoms.
In 2020, we started to develop RSoXS equipments andsucceeded in characterizing liquid-crystal materials. To
improve an accuracy of our RSoXS equipments, wemeasured chicken collagen and silica nanoparticles asstandard substances.
Our RSoXS measurements were performed at
UVSOR BL3U. Figure 1 shows a schematic draw of anexperimental setup. Samples of chicken leg’s collagenand 100nm-silica nanoparticle were fixed on Si3N4
membranes. The photon energy is 284 eV. Scattering
light were detected by soft x-ray camera (Andor
BN940P). This RSoXS equipment covers scattering
angles, 2θ, ranging from 0 to 15°.
Figure 2(a) shows a scattering image of the chicken
leg’s collagens. We find three weak ring structures.
From the image, we obtained a scattering intensity as
a function of scattering vector, q, which are shown in
Fig. 2(b). Three peaks at q = 0.105, 0.212, 0.320 nm-1
indicates that the sample of the chicken collagen haveperiodic structure of 59.3 nm, which is slightly different
from the reference value of 63.8 nm.
Figure 3(a) shows a scattering image of 100-nm(diameter) silica nanoparticles. We find striped ring
structures. From the image, we also obtained a scattering
intensity as a function of scattering vector, q. As shownin Fig. 3(b), we find oscillation structures. By using
theoretical equation of a scattering intensity forspherical sample, we fitted experimental curves withthose of the 110-nm nanoparticle.
Thus experimental results are slightly different from
actual values, suggesting that we need the standard
sample for calibrations of our RSoXS equipment.

Fig. 1. Schematic view of our RSoXS equipment.

Ⅲ-3

Fig. 2 (a) Scattering image of chicken leg’s collagens.
The color scale is a log scale. (b) Scattering intensity
as a function of scattering vector, q.

Fig. 3 (a) Scattering image of 100-nm silica nanoparticles.
The color scale is a log scale. (b) Scattering intensity
as a function of scattering vector, q. Red and blue lines
are experimental and theoretical one, respectively.

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Oxygen K-edge X-ray Absorption Spectroscopy of Aqueous Dimethyl
Sulfoxide Solutions at Different Concentrations
M. Nagasaka1, 2Institute for Molecular Science, Okazaki 444-8585, JapanThe Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan
1

2

Ⅲ-3

Dimethyl sulfoxide (DMSO) is a widely usedcosolvent, and aqueous DMSO solutions show
numerous physical properties that show maxima or
minima in the middle concentration region [1]. Several
studies determined microscopic structures of aqueous
DMSO solutions, where hydrogen bond (HB) structuresof S=O groups in DMSO with water are formed and arechanged at different molar fractions [2]. However, themechanism of the HB formation of DMSO with water
have not fully understood. In this study, we have studied
the concentration dependence of the HB structures of
DMSO with water in aqueous solutions by using O Kedge X-ray absorption spectroscopy (XAS).
The experiments were performed at soft X-ray
beamline BL3U. O K-edge XAS of aqueous DMSO
solutions were measured by using a transmission-type
liquid flow cell [3]. Liquid samples are exchanged bya tubing pump without changing the beam positions.
Figure 1 shows O K-edge XAS spectra of aqueous
DMSO solutions (DMSO)x(H2O)1−x at different
concentrations at 25 °C. In O K-edge XAS of neat water(x = 0.0), the pre-edge peak at 535 eV is assigned as
the transition of O 1s electron to the 4a1 unoccupied
orbital in water and reflects HB structures amongwater molecules, as observed in O K-edge XAS ofliquid water at different temperatures [4]. On the other
hand, the peak at 532 eV corresponds to the transitionof O 1s electron to the S=O π* orbital in DMSO [5].
From the fitting procedures, we have determined theenergy shifts of the pre-edge peaks in water and thefirst peaks of S=O π* orbitals in DMSO at the different
molar fractions of DMSO.
Figure 2 shows the energy shifts of the first peaks of
DMSO S=O π* orbitals from that of neat DMSO (x =1.0). By increasing the molar fraction of water (1 – x),
the S=O π* peaks show the higher energy shifts, whichshows two concentration regions with the border of x
= 0.4. In the DMSO-rich region (0.4 < x < 1.0), theslope of the energy shift is 164 meV / (1 – x). In thewater-rich region (0.05 < x < 0.4), on the other hand,
the higher energy shift of the S=O π* peak isaccelerated (271 meV / (1 – x)). The pre-edge peaks inwater also show characteristic concentration dependence,
which shows three concentration regions with theborders of x = 0.2 and x = 0.6. For revealing theconcentration dependence of the energy shifts in O Kedge XAS, we will perform molecular dynamics
simulations and inner-shell quantum chemical
calculations of aqueous DMSO solutions.

Fig. 1. O K-edge XAS spectra of aqueous DMSO
solutions at different concentrations.

Fig. 2. Energy shifts of the first peaks of DMSO S=O
π* orbitals from that of neat DMSO (x = 1.0) as afunction of molar fraction of DMSO.

[1] S. Roy and B. Bagchi, J. Chem. Phys. 139 (2013)
034308.
[2] K.-I. Oh et al., Angew. Chem. Int. Ed. 56 (2017)11375.
[3] M. Nagasaka and N. Kosugi, Chem. Lett. 50 (2021)
956.
[4] M. Nagasaka et al., J. Phys. Chem. B 121 (2017)10957.
[5] L. I. Vogt et al., RSC Adv. 10 (2020) 26229.

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BL3U

Carbon K-edge X-ray Absorption Spectroscopy of Aqueous Ethanol
Solutions at Different Concentrations
M. Nagasaka1,2, M. Bouvier1, H. Yuzawa1 and N. Kosugi1,2

Institute for Molecular Science, Okazaki 444-8585, JapanThe Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan
1

2

Aqueous ethanol (EtOH) solutions show anomaliesof thermodynamic and transport properties [1]. These
anomalies would be occurred by the intermolecularinteractions between EtOH and water (H2O). In theprevious studies, it is suggested that the EtOH-H2O
mixed clusters are formed in the middle concentration
region [2] and the hydrophobic hydration of EtOH isformed in the low concentration region [3]. In thisstudy, we have investigated the local structures aroundthe ethyl group in EtOH by using carbon K-edge X-ray
absorption spectroscopy (XAS) of aqueous EtOH
solutions at different concentrations.
The experiments were performed at soft X-ray
beamline BL3U. C K-edge XAS of aqueous EtOH
solutions were measured by using a transmission-type
liquid flow cell [4]. Liquid samples are exchanged bya tubing pump without changing the beam positions.
Figure 1(a) shows C K-edge XAS spectra ofaqueous EtOH solutions at different concentrations at
25 °C. Each spectrum is fitted by four peaks, where
peak A is the lowest peak around 287.3 eV. Figure 1(b)shows the energy shifts of peak A relative to that ofliquid EtOH (x = 1.0) as a function of the molar
fraction of EtOH (x). We have found that the energy
shift of peak A shows four concentration regions (I, II,
III, and IV). In the region I (1.0 > x > 0.8), peak A
shows the lower energy shift by increasing the molar
fraction of H2O. In the region II (0.8 > x > 0.25), peak
A shows the slightly higher energy shift by increasing
the molar fraction of H2O. The lower energy shift ofpeak A is observed in the region III (0.25 > x > 0.15)
and is accelerated by increasing the molar fraction of
H2O in the region IV (0.15 > x > 0.05).
From the inner-shell quantum calculations, we haveinvestigated the molecular interaction between EtOH
and H2O at the four concentration regions. In the region
I, the hydrogen bond (HB) structure of EtOH – EtOH issimply substituted to that of EtOH – H2O. In the region
II, the EtOH clusters are formed by the hydrophobic
interactions of the ethyl group in EtOH, resulting in theenhancement of the HB structure of H2O – H2O as
observed by O K-edge XAS [5]. Whereas a phasetransition like behavior is observed in aqueous methanol
solutions [6], there is no phase-transition like behavior
in aqueous EtOH solutions due to the stronghydrophobic interactions in EtOH. In the regions III andIV, the size of EtOH clusters becomes smaller, resulting
in the increase of the hydrophobic hydration of EtOH in
the HB network of H2O.

Ⅲ-3

Fig. 1. (a) C K-edge XAS spectra of aqueous EtOH
solutions at different concentrations. (b) Energy shiftsof peak A relative to that of liquid EtOH (x = 1.0) as afunction of molar fraction of EtOH (x).

[1] F. Franks and D. J. G. Ives, Q. Rev. Chem. Soc. 20(1966) 1.
[2]K. Nishikawa et al., J. Phys. Chem. 97 (1993) 10824.
[3] H. S. Frank and M. W. Evans, J. Chem. Phys. 13(1945) 507.
[4] M. Nagasaka and N. Kosugi, Chem. Lett. 50 (2021)
956.
[5] M. Nagasaka et al., UVSOR Activity Report 201947 (2020) 114.
[6]M. Nagasaka et al., J. Phys. Chem. B 118 (2014) 4388.

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The C–Si Bond Length of Organosilicon Compounds in Organic Solvent
Probed by Carbon K-edge X-ray Absorption Spectroscopy
S. Okumura1,2, M. Nagasaka1,2, H. Takaya1,3, and Y. Uozumi1,2

Institute for Molecular Science, Okazaki 444-8585, JapanThe Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan
3
Institute for Chemical Research, Kyoto University, Uji 611-0011, Japan
1

2

Ⅲ-3

Although the reactivity of organic compounds isclosely related to the bond length at the reactive site, it
is difficult to know the bond length in organic solvents
experimentally. Soft X-ray absorption spectroscopy(XAS) has a potential to determine the chemical bondsince soft X-ray XAS observes electronic structures oflight elements such as C, N, O, etc. Recently, we havedeveloped liquid flow cells for XAS in transmission
mode [1]. Hydration of cyanopyrazine on titaniumoxide catalysts has been studied by C K-edge XAS, but
this study only observed the reaction kinetics [2]. It is
still difficult to reveal the relation of the bond length at
the reactive site with the reactivity by soft X-ray XAS.
In this study, we have investigated the C–Si bondlengths of the organosilicon compounds in organic
solvents, which are key compounds for the Hiyama
cross-coupling reaction [3], by using C K-edge XAS.
The experiments were performed at soft X-ray
beamline BL3U. C K-edge XAS of the organosiliconcompounds in organic solvents were measured byusing a transmission-type liquid flow cell [1]. The
liquid samples were prepared in argon filled glovebox
and were flown to the liquid cell by using a syringe
pump. Liquid temperature was set to 25 °C.
Figure 1 shows the C K-edge XAS spectra of 100 mM
trimethoxy(phenyl)silane (1) in tetrahydrofuran (THF),
ethylene glycol-derived pentacoordinate spirosilicate(2) in ethylene glycol, and fluorotrimethoxy(phenyl)
silicate (3) in THF solution. The peak around 285 eV insilane 1 is assigned as the transition from the C 1s orbitalto the C=C π* unoccupied orbital in the phenyl group.
This peak is fitted by three peaks: Peak A is thetransition from the C atom bonded with Si, peak B isthat from the ortho sites, and peak C is that from themeta sites in the phenyl group. It means that peak A
reflects the C–Si bond lengths of the organosiliconcompounds. The energy position of peak A in silane 1 is284.56 eV. The peak A in silicates 2 and 3 show lower
energy shifts by −0.02 eV and −0.06 eV from that insilane 1, respectively. We have performed the structural
optimization of these organosilicon compounds by thequantum chemical calculations and found that the C–Si
bond length becomes longer with the order of compounds
1, 2, and 3. C K-edge inner-shell calculations revealed
that the peak A shows lower energy shifts by increasing
the C–Si bond lengths. These results are consistent withthe experiments. Therefore, it is revealed that due to thelonger C–Si bond of silicate 2, it showed the higher
reactivity in the Hiyama cross-coupling reaction thanthat of silane 1. On the other hand, the reactivity ofsilicate 3 was lower than that of silane 1 despite thelongest C–Si bond length [4]. The inertness of silicate 3
would be caused by other factors such as a steric barrier,which is now investigating by the quantum calculationof the transition state in the reaction.

Fig. 1. C K-edge XAS spectra of compounds 1, 2, and3 in THF or ethylene glycol. Dashed lines show thepeak positions of silane 1 obtained by curve fitting
procedures.

[1] M. Nagasaka and N. Kosugi, Chem. Lett. 50 (2021)
956.
[2] H. Yuzawa, M. Nagasaka and N. Kosugi, J. Phys.
Chem. C 119 (2015) 7738.
[3] S. Ichii, G. Hamasaka and Y. Uozumi, Chem. Asian J.
14 (2019) 3850.
[4] C. Amatore et al., Angew. Chem. Int. Ed. 53 (2014)
6982.

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BL3U

Direct Observation of a High Valent Oxo Species of a μ-Nitrido-Bridged
Iron Phthalocyanine Dimer Deposited on a Graphite Surface
in Aqueous Solution by Soft X-ray Absorption Spectroscopy
Y. Yamada1,2 and M. Nagasaka3

Department of Chemistry, Graduate School of Science, Nagoya University, Nagoya 464-8602, Japan
2
Research Center for Materials Science, Nagoya University, Nagoya 464-8602, Japan
3
Institute for Molecular Science, Okazaki 444-8585, Japanto the excitation of O1s – π* of Fe=O for 1oxo should
be observed at around 529 eV (Fig. 2c), whereas thepeaks for 1 having a coordinating H2O should beobserved at higher energy than 534 eV as shown in Fig.
2d (Fig. 2d). Therefore, it is considered that the peak
appeared at around 532.5 eV is assignable to theexcitation of O1s – π* of Fe=O for 1oxo. Next, we aregoing to observe the electrochemically generated 1oxoin H2O.
ONNNNFeNIII N
N
N

N

N
N
N
FeNIV N
N
N

N

N

N
N
N
N
FeNIV N
N
N

N
N
N
N
FeNIV N
N
N

H2O2

・ 0

1

Ⅲ-3

CH4

CH3OH
HCHO
HCOOH

Graphite

1oxoFig. 1. Potent methane oxidation catalyst 1 and its
reactive species 1oxo.
(a)

N

(c)

N
N
N
FeNIII N
N
N

N
N
N
N
FeNIV N
N
N

N

N
N
N
FeNIV N
N
N

N

N
N
N
FeNIV NNN

0.040

Oscillator strength

C membrane~ 20 nm

SiN membrane

・ 0

O
0.050

N

N

0.030

0.020

0.010

(b)

0.000

(d)

525

530

535

540

Photon energy / eV

OH2
N
N
N
N
FeNIII N
N
N

0.050

N

0.040

Oscillator strength

Methane is abundant in nature as natural gas ormethane hydrate. Therefore, efficient conversion of
methane into valuable raw chemicals such as methanol
is highly desired in order to use methane as a nextgeneration carbon resource. However, since highchemical stability of methane prevent its efficient C-Hbond activation, development of novel catalysts thatallow facile C-H bond dissociation of methane under
mild reaction condition is indispensable. We recently
found that a μ-nitrido-bridged iron phthalocyanine
dimer adsorbed on a graphite surface 1 (Fig. 1) efficiently
convert methane into methanol, formaldehyde, andformic acid in an acidic aqueous solution containing
H2O2 at a temperature below than 100 °C. It wasdemonstrated that 1 showed one of the most potent
methane oxidation activity among a variety ofmolecule-based catalysts and its activity was almost
comparable as that of natural particulate methane
monooxgenase (pMMO)[1]. Although it’s reactive
intermediate was confirmed to be a high valent iron-oxo
species 1oxo generated by the reaction with H2O2, theelectronic structure of 1oxo has never been investigated.
In our previous report, we confirmed that it is possible
to observe 1oxo directly by XAS under vacuum by using
a highly oriented pyrolytic graphite (HOPG) substrate
modified with the μ-nitrido-bridged iron phthalocyanine
dimer. In this study, we attempted to observe theconversion of 1 into 1oxo in an aqueous solution by using
XAS.
We first prepared a SiN membrane tip modified by
1 (Fig. 2a). A SiN membrane tip coated by 20 nm
thickness of carbon membrane was dipped in apyridine solution of the μ-nitrido-bridged ironphthalocyanine dimer. It was confirmed that the μnitrido-bridged iron phthalocyanine dimer was
successfully deposited on the carbon surface of the SiN
membrane tip by detecting the Fe L-edge XAS signals.
The SiN substrate modified with 1 was used for the
XAS measurement in an aqueous solution by using abeamline equipped with a transmission-type liquid flow
cell in BL3U of UVSOR [2]. The O K-edge XAS
spectra of 1oxo formed by the reaction with H2O2 wereobtained by using the Lambert-Beer law, ln(I0/I), where
I0 and I are the transmission signals of 1 in pure waterand 1 in a 0.5 % H2O2 aqueous solution, respectively.
It was found that the peak at around 532.5 eV wassignificantly increased after treatment with H2O2 (Fig.
2b). DFT calculation suggested that the peak assignable

Intensity / a.u.

1

N

0.030

N
N
N
FeNIV N
N
N

0.020

0.010

0.000

Photon energy / eV

525

530

535

540

Photon energy / eV

Fig. 2. (a) Structure of a SiN tip coated with 1, (b)Comparison of O K-edge XAS spectra of 1 before andafter treatment with H2O2. DFT-calculated O K-edge
XAS spectra for 1oxo (c) and 1(OH2) (d).

[1] Y. Yamada, M. Nagasaka et al., Chem Rxiv.
DOI : https://doi.org/10.26434/chemrxiv.14728860.v1.
[2] M. Nagasaka and N, Kosugi, Chem. Lett. 50 (2021)
956.

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Soft X-ray Absorption of Photocatalysts for Artificial Photosynthesis:
A Feasibility Study under Ultraviolet Light Irradiation
H. Onishi1,2, T. Hirai1, N. Ichikuni3 and T. Yoshida4

School of Science, Kobe University, Kobe 657-8501, Japan
Division of Advanced Molecular Science, Institute for Molecular Science, Okazaki 444-8585, Japan
3
Graduate School of Engineering, Chiba University, Chiba 263-8522, Japan
4
Reserch Center for Artificial Photosynthesis, Osaka City University, Osaka 558-8585, Japan
1

2

Ⅲ-3

Sodium tantalate (NaTaO3) is a semiconductor
photocatalysts which produces hydrogen–oxygen
mixed bubbles in the overall water splitting reaction,
when properly doped with metal cations [1]. We areconducting a series of studies to answer the question of
why doping with metal cations raised the quantum
yield of the reaction. Here, soft X-ray absorption isapplied for characterizing the electronic structure of
the photocatalysts in the presence and absence ofultraviolet (UV) light for bandgap excitation.
NaTaO3 particles doped with and without Sr cations
were prepared thorough a solid-state reaction. Oxygen
K-edge absorption of the particles was observed in
vacuum at room temperature with total electron yield.
Figure 1 shows the spectra of the pristine, undoped
particles.
The spectrum in the absence of UV light was wellfitted with three Gaussian functions peaked at 531.8,
532.8, and 537.2 eV (upper panel). The first andsecond peaks were assigned to electron transition fromoxygen 1s to 2p states which were covalently
hybridized with t2g states of Ta 5d orbitals. The third
peak present at a larger photon energy was assigned tothe transition to oxygen 2p states hybridized with eg
states of the Ta orbitals. NaTaO3 is a perovskitestructured compound involves TaO6 octahedra, which
provide the 5d orbitals split into t2g and eg states.
When the photocatalyst particles were irradiatedwith steady UV light produced by a 200-W Hg–Xe
lamp, absorption related to the t2g final states, the firstpeak at 531.8 eV in particular, weakened relative to thethird peak, as presented in the lower panel of Fig. 1. A
possible reason of the weakened absorption is the
conduction band partially filled with bandgap-excitedelectrons. The density of vacant states, the final statesof the K-edge absorption, should have decreased by theelectrons excited from the valence band. Covalenthybridization of the oxygen 2p and Ta 5d orbitals
would also be limited to weaken 5d-states character ofthe final states [2], since the oxidation state of Ta
cations decreased from +5 to 4+ by the bandgap
excitation.

Fig. 1. Oxygen K-edge absorption spectra of pristine
NaTaO3 photocatalyst particles observed in theabsence (upper panel) and presence (lower panel) of
UV light for bandgap excitation. The observed spectra(black curves) were fitted with Gaussian functions (redcurves). The spectra reconstructed with the functions(blue curves) are shown with residuals (thin black
curves at the top).

[1] H. Onishi, ChemSusChem 12 (2019) 1825.
[2]F. Frati, M. O. J. Y. Hunault, F. M. F. de Groot, Chem.
Rev. 120 (2020) 4056.

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Variation of the Resonance Band of Water in Soft X-Ray Absorption
Spectra of Aqueous Acetone Solutions
K. Okada1,2, C. Sugahara2, H. Iwayama3,4 and M. Nagasaka3,4

Graduate School of Advanced Science and Engineering, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
2
School of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
3
Institute for Molecular Science, Okazaki 444-8585, Japan
4
School of Physical Sciences, The Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan
1

Acetone is miscible with water in any ratio. The
binary mixture is a typical aprotic–protic solvent system[1]. A role of the acetone molecule acting as a hydrogenbond acceptor adds characteristic properties of water.
For instance, the partial molar volume of water in thismixture is 14.25 cm3/mol at 25 °C [2], which is muchless than the molar volume of water. Such specific watermolecules have a different electronic structure from thatof bulk water. The study of the electronic structure of
hydrated water is of essential importance because it
provides fundamental information on the structure of
aqueous solutions in general (e.g., [3]). In this report theO K-edge absorption spectra with various fractions ofacetone are recorded for extracting the hydrated watercomponents through an excess function: We expect that
there exists some correlation between the hydration anda deviation from Beer’s law at some photon energy.
Photoabsorption spectra of the solutions were
measured in the oxygen K-edge region on the soft Xray beamline, BL3U. A pair of windows made of thinsilicon nitride membrane was used for the sample cell.
The incident photon energy was calibrated to the peakat 530.88 eV of a polymer film [4]. The absorption
coefficient was evaluated so as to match the value at
547.85 eV to that tabulated in the database [5]. The
sample solutions were prepared by mixing acetone
with purified water to give 0–0.50 molar fractions ofacetone.
Distinct features are found in the absorption spectra.
Figure 1 displays some of the measured absorption
spectra of water and aqueous acetone solutions. The π*
resonance peak of acetone located at 531.13 eV for
pure liquid is now observed at 531.33 eV for thesolution with the molar fraction of acetone of 0.10. The
shift depends non-linearly on the molar fraction: Thechange is larger for a dilute region. The 4a1 resonanceband of water has a peak at 534.56 eV for pure waterand at 534.46 eV for the 1:1 molar mixture (not shownin Fig. 1). The change around the molar fraction of
0.25 is noticeable, indicating a greater change in theelectronic structure of water around this concentration.
Apparent bathochromic shift (or red shift) of the latter
resonance peak is reasonable on the basis of chemical
shift because the water molecule gets electron-rich if it
receives electrons from the carbonyl oxygen of theacetone molecule. One can safely conclude that theabsorption component of the hydrated water isembedded in the lower energy side of the band and isassigned to the resonance transition of water acting asa hydrogen-bond donor.
Further discussion requires a quantitative analysis of
the spectra. Additivity of Beer’s absorption law is valid
for non-interacting mixtures. Conversely, a deviationfrom the absorption law indicates an extent ofinteraction between the components. The deviation isexpressed as the excess absorbance. The results of theanalysis will be published elsewhere.

Ⅲ-3

Fig. 1. The O K-edge absorption spectra of liquidwater and aqueous acetone solutions measured for aseries of molar fractions of acetone.

[1] A. J. Parker, Quart. Rev. Chem. Soc. (London) 16(1962) 163.
[2] E. V. Ivanov, V. K. Abrosimov and E. Y. Lebedeva,
J. Sol. Chem. 37 (2008) 1261.
[3] S. Ohsawa, T. Tokushima and K. Okada, J. Phys.
Chem. B 125 (2021) 1881.
[4] M. Nagasaka, H. Yuzawa, T. Horigome and N.
Kosugi, J. Elec. Spectrosc. Relat. Phenom. 224 (2018) 93.
[5] C. T. Chantler et al., NIST Standard Reference
Database 66 (1995; last update in 2005), available athttps://www.nist.gov/pml/x-ray-form-factorattenuation-and-scattering-tables.

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Oxygen K-edge X-ray Absorption Spectroscopy of Molecular Oxygen
Adsorbed on Lipid Bilayers
F. Kumaki1,2, M. Nagasaka3,4, Y. Kinjo5, R. Tero5, Y. Okano3, M. Fujimoto3,4 and J. Adachi1,2Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tsukuba 305-0801, Japan
2
School of High Energy Accelerator Science, The Graduate University for Advanced Studies (SOKENDAI),
Tsukuba 305-0801, Japan
3
Institute for Molecular Science, Okazaki 444-8585, Japan
4
School of Physical Sciences, The Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan
5
Toyohashi University of Technology, Toyohashi 441-8580, Japan1

Ⅲ-3

Some porphyrin complexes, such as the photosynthetic
pigment chlorophyll, are known to produce singlet
oxygen (1O2) by transferring energy to oxygen moleculesthat is triplet oxygen (3O2) in the surrounding environment
at the photo-excitation and relaxation processes due tolight absorption. Singlet oxygen is high-reactive. It cancause damage to biological cells or the sample itself inspectroscopic experiments. In generally, the sample
solution is bubbled with argon gas to displace thedissolved oxygen to avoid the generation of singlet
oxygen at the measurement of a spectrum in visible rightregion. On the other hand, the process of singlet oxygen
generation accompanying with photoexcitation andrelaxation processes of photosensitizers such as
porphyrin complexes is applied in cancer treatment as
photodynamic therapy [1]. Elucidating the dynamics of
singlet oxygen production in such a wet environment is
expected to contribute to further research of chemistry
and medicine.
We designed the way to measure directly the electricstates of singlet oxygen occurred in solution by O Kedge x-ray absorption spectroscopy (XAS). Timeresolved XAS measurement system with synchronizedsoft X-rays pulse (530 eV, 128 ps) and visible laser
pulses (400 nm, 130 fs) have been developed and will
be applied. The lifetime of singlet oxygen in liquid is
3 μs [2], which can be measured with the 128 ps time
resolution of synchrotron radiation. In this measurement,
a method to measure a dissolved oxygen spectrum wasestablished as a preliminary step for XAS measurementsof singlet oxygen.
The XAS spectrum was measured by using thesolution XAS measurement system at UVSOR BL3U[3]. The liquid cell consists of a solution layer
sandwiched between two Si3N4 membranes. Lipid
bilayers ware formed on Si3N4 membranes by pumping
the lipids vesicle aqueous solution to flow into the liquidcell. Then, dissolved oxygen was kept on the lipid
bilayers by continuously pumping the buffer solution(NaCl 100 mM, HEPES 25 mM) bubbled with oxygengas at a flow rate of 100 µl/hr. By increasing the heliumpressure in the sample chamber and making the solution
layer as thin as possible, the spectrum that has theemphasized peak of dissolved oxygen on the lipid
bilayer was measured. In the measurement of singlet
oxygen, chlorophyll a, added as a photosensitizer to thelipid bilayer, is photoexcited by visible laser with 400
nm which is SH (second order harmonic) of Ti:sapphirelaser. We are planning to measure an O K-edge XAS
spectrum of the singlet oxygen produced by the energy
transfer at the relaxation process of the photo-excitedtriplet state of chlorophyll a.
Figure 1 shows the O K-edge XAS spectrum ofliquid bilayer measured in this experiment. The peakat around 531 eV corresponds to dissolved oxygen
absorbed on lipid bilayer which is in the ground state.
Since the O K-edge XAS spectrum of water is inhigher energy region than 533 eV, the spectrum of
dissolved oxygen can be clearly distinguished.

Fig. 1. The O K-edge XAS spectrum of the lipid
bilayer. The peak around 531 eV corresponds to a peakof dissolved oxygen absorbed on the lipid bilayer.

[1] M. Ethirajan et al., Chem. Soc. Rev. 40 (2011) 340.
[2] C. A. Long and D. R. Kearns, J. Am. Chem. Soc. 97(1975) 2018.
[3] M. Nagasaka et al., J. Electron Spectrosc. Relat.
Phenom. 224 (2018) 93.

11814 Ⅲ03-

BL4U

Ⅲ -3. Chemistry

BL4U

Position-Sensitive Soft X-ray Absorption Spectroscopy of Carbon-based
Catalysts for Redox Flow Battery
E. Hosono1,2,3, D. Asakura1,2,3, H. Yuzawa4, T. Ohigashi4,5 and A. Ohira1,2,3

Global Zero Emission Research Center, National Institute of Advanced Industrial Science (AIST),
Tsukuba 305-8569, Japan
2
Research Institute for Energy Conservation, AIST, Tsukuba 305-8565, Japan
3
AIST-UTokyo Advanced Operando Measurement Technology Open Innovation Laboratory (Operando-OIL),
Kashiwa 277-8565, Japan
4
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
5
School of Physical Sciences, The Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan1

Utilization of renewable energy such as solar celland wind power is indispensable for reduction of CO2
emission and realizing zero emission society. To stably
use the renewable energy in practical use, developmentof large-scale energy storage devices is needed. Redox
flow battery (RFB) is one of the candidates [1] as well
as Li-ion battery (LIB).
The electrolyte solutions of RFB play a role on theredox reaction as both positive and negative electrodes(i.e., catholyte and anolyte) (Fig. 1), which is different
from LIB where the solid-state electrodes (cathode andanode) exhibit the redox reaction. The carbon-based
electrodes are soaked in electrolyte solutions and H+ inthe solutions can move through an ion-exchange
membrane between the two electrodes bycharge/discharge (Fig. 1). To raise the efficiency of theredox and H+ conduction, the performance of carbonbased catalysts combined with the electrodes should be
investigated. Electronic-structure analysis using soft
X-ray absorption spectroscopy (XAS) is suitable forstudying the performance. Then, scanningtransmission X-ray microscopy (STXM) provides not
only the information of electronic structure, but also its
distribution with a high spatial resolution (<100 nm).
Thus, we adopted STXM at the C K-edge to carbonbased catalysts for RFB. The STXM measurements
were conducted at BL4U, UVSOR.
Figure 2 shows a pinpoint C K-edge absorption
spectrum (in transmission mode) of a selected area for
a graphene sample. The peaks at 285.4 and 291.8 eV
in Fig. 2 correspond to π* and σ* peaks, respectively[2,3,4]. The weak π* peak compared to the σ* peak issimilar to the spectrum for graphite with normal
incidence [2,3], which suggests that the graphene
layers stack along the X-rays. Almost all the area of thegraphene particle in the STXM image showed similar
XAS line shape. This is important information because
the catalytic performance would be dependent on theorientation of stacking. Furthermore, the spectrum
shows no peak between the π* and σ* peaks, indicating
almost no contamination.
In future, we will try in situ/operando STXM byconstructing a special cell for RFB.

Ⅲ-3

Fig. 1. A schematic picture of RFB using vanadium.

Fig. 2. A pinpoint C K-edge XAS spectrum of a specificarea (~350 nm × ~180 nm) of the graphene sample.

[1] For example, A. Z. Weber et al., J. Appl. Electrochem.
41 (2011) 1137.
[2] M. T. Chowdhury et al., Phys. Rev. B 85 (2012)
115410.
[3] M. Abbas et al., Appl. Phys. Lett. 87 (2005) 051923.
[4] A. Li et al., Electrochim. Acta 276 (2018) 153.

11915 Ⅲ03-

BL4U
Ⅲ -3. Chemistry

BL4U

Investigating Electrochemical Reactivity on Ni(OH)2 Electrocatalyst in
Alkaline Electrolytes
J. Kim1 T. Ohigashi 2,3 and J. Lim1

Department of Chemistry, Seoul National University; 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
2
Editorial Board, UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan3
School of Physical Sciences, The Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan
1

Ⅲ-3

During the electrochemical reaction, the phasetransformation of energy storage/conversion materials
accompanies intrinsic variation on physico-chemical
properties. In particular, the energy conversion materials(catalysts) in aqueous system suffer severe chemical
and/or morphological changes during reaction. [1]These changes are governed by the thermodynamics
that the material exists as a possible stable phaseaccording to pH or potential. In dynamic condition, thelocally generated chemical equilibrium induces theevolution of electrochemical active phase in nanoscale,
which are responsible for electro- catalytic activity andstability.
Among various energy conversion materials,
Ni(OH)2, which exhibits superior oxygen evolution
reaction (OER) activity, experience multiple phasetransformation via dehydrogenation process during
OER. [2] Specifically, as hydrogen atom is extracted
from the lattice, -Ni(OH)2 (Ni2+) can convert to moreoxidized phase such as -NiOOH (Ni3+) and -NiOOH(Ni3.6+), and the OER activity is highly dependent onthese high valence state of Ni phases. Additionally,lattice oxygen atoms also play an important role in the
OER due to bond formation /breaking process withactive metal site. An understanding of the active phaseevolution and the coordination of oxygen atom withactive metal site is a fundamental prerequisite fordesigning improved OER catalysts, but it remains a
crucial challenge to identify the generation andevolution of nanoscale active phase spatially due to alack of characterization technique. To investigate theevolution of OER active phase (-NiOOH or -NiOOH),
we implemented operando scanning transmission X-ray
microscopy (STXM) to track the change in Ni oxidation
state that indicates the phase transformation of Ni(OH)2during OER at the Pohang Light Source STXM
beamline 10A1.
Distinctive feature in the phase transformation of Ni(OH)2 is that Ni3.6+ phases, -NiOOH at 1.70 V versus
reversible hydrogen electrode (RHE), are reduced at 1.8
V and 1.9 V versus RHE, where OER is highly occurred.
(Fig. 1) From this observation, we speculate that there
are two possibilities. First, potassium ion (K+) inelectrolyte could intercalate into the slab, leading to
reduction of the Ni oxidation state owing to the charge
neutrality. [2] Second, during OER, oxygen vacancies
are generated in the catalyst. [3] To confirm thegeneration of oxygen vacancies in high anodic potential
region, we conducted ex situ STXM measurement of -Ni(OH)2 at UVSOR BL4U for investigating the change
in O K-edge absorption spectra.
Figure 2a shows particle-averaged O K-edge spectraof -Ni(OH)2 at different potentials, revealing that the
pre-peak A (532 eV), assigned to the hybridization of Ni
3d and O 2p orbitals states with eg orbital symmetry andthe d7 (Ni3+) electron configuration, is varied at different
potentials. [3] In particular, the intensity of peak A
suddenly decreases at 1.65 V, suggesting the return ofelectrons to Ni site. It can be attributed to the formationof oxygen vacancies and the decreased oxidation stateof Ni site. From our results, we conclude that generationof the oxygen vacancy during OER could induce
reduction of the active phase (-NiOOH), consistent
with our operando STXM results.
OCV

1.40 V

1.50 V

1.60 V

1.70 V

1.80 VNi2+

1.90 V

1.10 V

Ni3.6+

500 nmFig. 1. Operando chemical composition mapping imagesof -Ni(OH)2 electrocatalyst during OER.
(Unpublished)abFig. 1. a. Voltage-dependent particle-averaged O Kedge STXM-XAS spectra. b. Intensity of peak A at
different potentials.

[1] Chung, D.Y., Lopes, P.P., Farinazzo Bergamo Dias
Martins, P. et al., Nat Energy 5 (2020) 222.
[2] Mario González-Perea et al., ECS Trans. 36 (2011)
299.
[3] Kang, J., Qiu, X., Hu, Q.et al., Nat Catal. 4 (2021)
1050.

12016 Ⅲ03-

BL4B

Ⅲ -3. Chemistry

BL4B

Quadruple Auger Decay of the Xe 3d5/2 Core-Hole State Investigated byMultielectron−Ion Coincidence Spectroscopy
Y. Hikosaka

Institute of Liberal Arts and Sciences, University of Toyama, Toyama 930-0194, Japanthe state energies of the Xe4+ 4d−15p−3 levels measured
from 2P1/2 or 2P3/2 of 5p−5, and thus many different Xe4+
4d−15p−3 levels are formed through the third-step Auger
decay of Xe3+ 4d−25p−1 → Xe4+ 4d−15p−3.
0Kinetic energy of slower electron (eV)20Counts

Decay from 4d-25p-1

15

250 500
20

15

4d-25p-1→ 4d-15p-3

10

10
-1

-3

4d 5p
→ 5p-5
5

0

5

0

5

10

15

20

25

30

35

Kinetic energy of slower electron (eV)

Magnetic bottle electron spectrometer is a very
efficient electron spectroscopic method, utilizing an
inhomogeneous magnetic field to capture all theelectrons formed by photoionization. Its use enables us
to perform multielectron coincidence spectroscopy very
effectively. While the electrons captured over 4πsteradian solid angle are guided to an MCP detector
ending a long flight path, ions formed together withelectrons can be also detected with the same detector, byapplying a pulsed electric field to the photoionization
region [1]. To improve the efficiency in multielectronion coincidence measurements, an MCP detector with alarge open area ratio (nominally 90 %) was recently
introduced in our magnetic bottle electron spectrometer[2].
The usefulness of this improved coincidence
efficiency is demonstrated by a six-fold coincidence
about the quadruple Auger decay of the Xe 3d5/2 corehole state. Figure 1 shows energy correlations between
the two Auger electrons emitted from Xe3+ 4d−25p−1,
which was derived from six-fold coincidences including
the 3d5/2 photoelectron, first-step Auger electron
forming 4p-14d-1, second-step Auger electron forming
4d−25p−1, and Xe5+. The additional coincidence with the
product Xe5+ ions effectively isolates the events
associated with the quadruple Auger decay. On the twodimensional map in Fig. 1, remarkable island structures
are observed in the area indicated by a square. The fasterand slower electrons forming the island structures are
assignable to the third-step Auger decay of Xe3+
4d−25p−1 → Xe4+ 4d−15p−3 and the fourth-step Auger
decay of Xe4+ 4d−15p−3 → Xe5+ 5p−5, respectively.
Essentially the same coincidence structure wasobserved in a previous multi-electron coincidence
measurement [3]. Note that the previous observation
was occurred in correlations between two electronsobserved in coincidence with the 3d photoelectron andfirst-step Auger electron, and thus as four-electron
coincidences.
One may see that the island structures lie on several
diagonal lines defined by x + y = constant. This isbecause the sums of the two Auger electrons correspondto the energy differences between Xe3+ 4d−25p−1 and
Xe5+ 5p−5 levels. Here, the appearance of multiple
diagonal lines is due to the contributions from different
levels of initial 4d−25p−1 and final 5p−5. The right panelof this figure shows the projection of the island
structures toward the y axis of the two-dimensional map.
The projection curve exhibits sharp peaks due to thefourth-step Auger decay of Xe4+ 4d−15p−3 → Xe5+ 5p−5.
The kinetic energies of the sharp peaks correspond to0

Kinetic energy of faster electron (eV)Fig. 1. Energy correlation map between two Auger
electrons ejected in the quadruple Auger decay of theXe 3d5/2 core-hole state, derived from six-foldcoincidences including the 3d5/2 photoelectron, firststep Auger electron forming 4p-14d-1, second-stepAuger electron forming 4d−25p−1, and Xe5+ ion, andthus it displays the energy correlation between the twoAuger electrons emitted in the decay of Xe3+ 4d−25p−1.
The right panel plots the projection of the coincidence
counts in the region x = 14-24 eV toward the y axis,
which exhibits the structures resulting from the fourthstep Auger decay of Xe4+ 4d−15p−3 → Xe5+ 5p−5.

[1]Y. Hikosaka and E. Shigemasa, Int. J. Mass Spectrom.
439 (2019) 13.
[2] Y. Hikosaka, J. Electron Spectrosc. Rel. Phenom.
255 (2022) 147158.
[3] I. H. Suzuki et al, J. Phys. B: At. Mol. Opt. Phys. 44(2011) 075003.

12117 Ⅲ03-

Ⅲ-3

BL4B
Ⅲ -3. Chemistry

BL4B

Ion Branching Ratio for the Xe 4p Auger Decay Studied by
Photoelectron−Ion Coincidence Spectroscopy
Y. Hikosaka

Institute of Liberal Arts and Sciences, University of Toyama, Toyama 930-0194, Japan

Ⅲ-3

Binding energy of Xe+ (eV)
250

200

150

100

250000Intensity (arb. units)

Photoelectron spectroscopy has revealed an anomalous
photoelectron structure of the 4p core-hole state in Xe[1]. In a photoelectron spectrum, the expected 4p1/2
photoelectron line is dissolved and no longer visible,
whereas the 4p3/2 structure consists of several finecomponents. These observations imply the breakdownof the independent particle model, resulting from thestrong interaction between the 4p-1 and 4d-2nf/4d-2εf
configurations [2]. In this work, the ion branching ratio
associated with the Auger decay of the 4p core-hole stateis inspected. A magnetic bottle electron spectrometer withion detection capability [3,4] was employed in this study,
to conduct an efficient photoelectron-ion coincidence
measurement. The measurement was implemented at a
photon energy of 391.7 eV (bandwidth of ~0.2 eV), i.e.
~240 eV above the 4p threshold.
Figure 1 presents a photoelectron spectrum of Xe andthose filtered by coincidences with different XeZ+ ions
(Z = 1-6). Photoelectron structures associated withejections of electrons from the N and O shells are
exhibited in these spectra. The ion detection efficiencies
were compensated for the spectral intensities of thecoincidence spectra; thus, the relative intensities ofindividual photoelectron structures in these spectra
reflect the ion branching ratios associated with the
decays of these core-hole states. The ion branchingratios of the individual core-holes states were alreadystudied by Eland et al. with the same coincidence
method [5].
The photoelectron spectrum (Fig. 1 top) shows the 4p
photoelectron structure consisting of a peak around a
kinetic energy of 245 eV and a remarkable shoulder inthe lower kinetic energy side. As already pointed out by
Eland et al. [5], the determination of the ion branchingratio of the 4p decay is not straightforward, because thedetermined ratio varies greatly with the photoelectron
range considered. When only the peak range around a
kinetic energy of 245 eV is considered, the formation of
Xe3+ is dominant and a sizable Xe4+ formation isprobably identified. This is consistent with a multielectron coincidence study which reports a dominant
Xe3+ formation for the main 4p photoelectron peak [6]and also with a recent calculation [7]. On the other hand,the shoulder part of the 4p photoelectron structure
mainly produces Xe4+ ion. The shoulder part can be
ascribed to double photoionization into the 4d-2 states,
which is enhanced by the virtual super Coster-Kronigtransition [2] of 4p-1 → 4d-2εf over several tens of electron
volts [8]. The formed 4d-2 states dominantly proceed tosequential fillings of the double 4d core-holes [8],resulting in the dominant formation of Xe4+ ion.

50

0

4d-1

2000001500004p-1

100000

4s-1

50000
0

sat.

5p-1
5s-1

Xe+
Xe2+
Xe3+
Xe4+
Xe5+
Xe6+
150

200

250

300

350

400

Kinetic energy of electron (eV)Fig. 1. Photoelectron spectrum of Xe measured at a
photon energy of 391.7 eV, and coincidence spectra
obtained by filter with different XeZ+ ions (Z = 1-6).
The intensities of the coincidence spectra werecorrected by the ion detection efficiencies.

[1] S. Svensson et al., Phys. Scr. 14 (1976) 141.
[2] G. Wendin and M. Ohno, Phys. Scr. 14 (1976) 148.
[3] Y. Hikosaka and E. Shigemasa, Int. J. Mass Spectrom.
439 (2019) 13.
[4] Y. Hikosaka, J. Electron Spectrosc. Rel. Phenom. 255(2022) 147158.
[5] J. H. D. Eland et al., J. Phys. B 48 (2015) 205001.
[6] Y. Hikosaka et al., Phys. Rev. A 76 (2007) 032708.
[7] Z. Liu et al., Chin. Phys. Lett. 38 (2021) 023201.
[8] Y. Hikosaka et al., Phys. Rev. Lett. 98 (2007) 183002.

12218 Ⅲ03-

BL4B

Ⅲ -3. Chemistry

BL4B

Electronic Structure Analysis of Ni Complex Bearing N-Heterocyclic
Carbene Ligand Using Ni L2,3-edge X-ray Absorption Spectroscopy
Y. Uetake1,2, Y. Yamauchi1 and Y. Hoshimoto1

Division of Applied Chemistry, Graduate School of Engineering, Osaka University, Suita 565-0871, Japan
Innovative Catalysis Science Division, Institute for Open and Transdisciplinary Research Initiatives (ICS-OTRI),
Osaka University, Suita 565-0871, Japan
1

2

Recently, we have synthesized a Ni(0) complex
bearing tris(pentafluorophenyl)borane (BCF) as anelectron accepting Z-type ligand and N-heterocycliccarbene as an ancillary ligand (1). Single crystal X-ray
diffraction (SC-XRD) analysis of 1 revealed that itexhibits a square-planer structure typical of Ni(II)complexes, unlike the tetrahedral geometry that iscommon for Ni(0) complexes probably due to thesterically demanding BCF ligand. Interested in theelectronic structure of 1 which contradicts the ligand
field theory, we have performed Ni K-edge X-ray
absorption spectroscopy (XAS) of this complex at
SPring-8 BL14B2 beamline and found that this complex
possessed low-valent Ni(0)-like electronic structure.
However, since Ni K-edge XAS basically corresponds
to the electron transitions from 1s to a vacant 4p orbital
because of the Fermi’s golden rule [1], it is difficult toclarify the details of the electronic structure of 3dorbitals which determines the characteristics of metal
complexes. In this study, Ni L2,3-edge XAS experimentsof the Ni-BCF complex were investigated.
Ni L2,3-edge XAS experiments were performed at
the BL4B beamline using partial fluorescent yields(PFYs) method with silicon drift detector (SDD). A
stainless-steel sample holder with double-sided
conductive carbon tapes was attached to a transfer
vessel, which was connected to a glovebox. The insideof the glovebox was evacuated using a rotary pump forat least 30 min, and then, filled with argon gas. The
powder sample was applied on a carbon tape, andrubbed with the back of a spatula. After storing thesample holder in the vessel, the gate valve was closed.
The vessel was detached from the glovebox, and then,attached to the main chamber. The air in the mainchamber was evacuated by a rotary pump, and the gate
valve was slowly opened after the pressure level
reached in the order of 10–3 Pa. A turbo-molecular pump
was then activated to create a high vacuum environment.
XAS measurements were performed under the pressureless than 5×10–5 Pa.
Ni L2,3-edge XAS data of 1, 2 and 3 are shown in Fig.
1. Although the peak intensity of 1 was different from
Ni(II) complex 3, the peak position of 1 was similar tothat of 3 which has octahedral ligand field rather thantetrahedral Ni(0) complex 2, indicating the intrinsic
geometrical similarity between the square-planer andthe octahedral. Meanwhile, slightly intense first peak of
1 observed at 852.5 eV was assigned as the electrontransition from 2p3/2 to 3dx2-y2 orbital. This result

indicated the low d-electron occupancy in 3dx2-y2 level
due to the σ-backdonation from Ni 3dx2-y2 orbital tovacant p orbital of BCF. In addition, the peak area of 1
(15.5) was closer to 2 (11.5) rather than 3 (25.3) (Table
1). Considering that the peak area reflects the transition
probabilities of the electrons [2,3], the d-electron
occupancy of 1 would be closer to the Ni(0) state rather
than to the Ni(II) state, which is consistent with the Ni
K-edge XAS experiment. In addition, the slight increaseof the L2,3-edge intensity of 1 would reflect the polarizedNiδ+–Bδ– bonding state.

Ⅲ-3

Fig. 1. Ni L2,3-edge XAS data of 1, 2 and 3.
Table 1. Peak area of Ni L2,3-edge XAS data after
normalization.
Peak area
L3
L2
L3 + L2
1
10.5
5.1
15.5
2
7.8
3.7
11.5
3
17.3
8.0
25.3
[1] P. M. A. Dirac, Proc. Roy. Soc. A 114 (1927) 243.
[2] E. I. Solomon, S. P. Cramer et al., J. Am. Chem. Soc.
115 (1993) 2968.
[3] K. M. Lancaster et al., J. Am. Chem. Soc. 141 (2019)
18508.

12319 Ⅲ03-

BL5B
Ⅲ -3. Chemistry

BL5B

Evaluation of Absorption Stability of a Hydrogen Absorption Cell
M. Taguchi1, M. Kuwabara1, T. Katsumata1, M. Tateyama1, K. Yoshioka2,3, Y. Suzuki3,
K. Goda4, K. Inoue4, A. Tomioka4 and A. Yamazaki4

Department of Physics, College of Science, Rikkyo University, Tokyo 171-8501, Japan
Department of Complexity Science and Engineering, Graduate School of Frontier Sciences, The University of Tokyo,
Chiba 277-8561, Japan3
Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo,
Tokyo 113-0033, Japan
4
Department of Earth and Planetary Physics, Faculty of Science, The University of Tokyo, Tokyo 113-0033, Japan
1

2

Ⅲ-3

A hydrogen absorption cell (HAC) is a unique
optical filter which enables us to estimate density andtemperature distributions and an isotope ratio ofhydrogen atoms escaping from a planetary atmosphereby detecting a hydrogen Lyman α emission of aplanetary corona. The HAC is especially suitable for a
payload of a planetary mission because of its small sizeand light weight. However, no measurement of aplanetary corona by a HAC has been successful so far.
Development of a newly designed HAC has beenproceeded by the proposers, and it has been decided
that the HAC is on board Comet Interceptor which isan ESA mission to investigate an atmosphere of a comet.
Absorption efficiency of the HAC has been improved,
but its lifetime has not yet been confirmed. Absorption
performance should be highly stable during the mission
lifetime of several years. Here we present a result of anexperiment in which absorption stability of a protomodel HAC was evaluated using the spectrometer at
BL5B of UVSOR.
The HAC and a Kr cell were installed in the beamline.
The Kr cell, which contains Kr gas with a pressure of
500 Pa, was used for wavelength calibration of thespectrometer. The grating and mirror combination of“G3M5” was selected. The slit width and the pinhole
diameter were 0.01 mm and 1 mm, respectively.

Dimension of the HAC isφ35 mm and L40 mm.
Pure hydrogen gas filtered by a palladium filter with apressure of 200 Pa was filled in the HAC. One of thefilaments on the HAC was used for this stability test.
Filament voltage was fixed at 5.73 V, which heats up
the filament at a temperature of approximately 1800 K.
A set of data consists of four spectra obtained withcombinations of the filament on and off and the beamon and off from 121.1 nm to 122.0 nm with a scan stepof 0.01 nm. It took approximately 70 min to acquire aset of data.
Figure 1 shows 8 absorption spectra of hydrogen
Lyman α consecutively obtained by the HAC during a
beamtime of 12 h. The depth of absorption almost
unchanged, though the filament current slightly
decreased from 0.170 A at the beginning to 0.167 A atthe end. Accordingly, the filament temperature
estimated from the voltage and current slightly
increased. During the beamtime of four weeks thisfilament was activated for longer than 30 h, but nosignificant degradation was observed.
All the absorption spectra show an increasing trend
from the shorter wavelength to the longer wavelength.
The reason for this trend is unclear, but it might berelated to any variation in the environment.

Fig. 1. Absorption spectra of hydrogen Lyman α consecutively obtained by a HAC under the same condition ofgas pressure and filament voltage with the same filament.

12420 Ⅲ03-

Ⅲ-4
Surface,
Interface andThin Films

BL5UⅢ -4. Surface, Interface and Thin Films

BL5U

Polarization-dependent Photoelectron Intensity in Ca-doped Graphene
S. Ichinokura1, K. Tokuda1, K. Tanaka2 and T. Hirahara1

Department of Physics, Tokyo Institute of Technology, Tokyo 152-8551, Japan
2
UVSOR Facility, Institute for Molecular Science, Okazaki 444-8585, Japan

1

Orbital symmetry strongly influences the interaction
between light and electrons. When polarized light isirradiated on a material, the electronic excitation obeys
the dipole selection rule; electrons in orbitals with oddand even-parity are excited by s- and p-polarized light(described as s- and p-pol. hereafter), respectively.
Therefore, in angle-resolved photoemission spectroscopy(ARPES), complemental intensity maps will be obtained
when the s- and p-linear polarized lights are used.
The remarkable high-carrier mobility in grapheneoriginates from its characteristic π-orbital band called
Dirac cone. The light-matter interaction of graphene
through the π-electron has attracted considerable
attention. For example, the photoelectron intensity of
the Dirac electronic state varies cyclically on the kx-ky
plane for the polarized light [1]. Here, chirality plays
an essential role in polarization dependence. In Liintercalated bilayer graphene (C6LiC6), two Diraccones with different chirality overlap around the Γpoint of the Brillouin zone (BZ). The chiral symmetryis broken due to the lattice distortion by Li, leading to
the gap opening at the Dirac point. These properties
were clarified by laser-ARPES measurements [2].
Ca-intercalated graphite and graphene becomesuperconducting at relatively high temperatures inlayered and two-dimensional materials [3-5]. In
addition to the Dirac cones, a free-electron-like state
called interlayer band (ILB) exists as an occupied statein those systems. Since ILB has different symmetry
from π-band, dipole selection rule and chirality effects
are expected to coexist in C6CaC6.
To resolve the coexistence of the two effects, we
performed high-resolution polarization-dependent
ARPES measurements on Ca-intercalated bilayer
graphene, C6CaC6 at BL5U and BL7U. As shown in
Figure 1(a), C6CaC6 was prepared on a Ca-terminated
SiC substrate. Figure 1(b) shows the ARPES spectrum
obtained by s-pol. A double Dirac cone was seen. The
Dirac cones are folded into Γ point from K point of thegraphene’s BZ due to the √3×√3 periodicity of Ca. The
doubling is caused by the interlayer interaction
between two graphene layers.
On the other hand, a parabolic band (stressed bydashed line) was much more prominently observed
than the double Dirac cones when p-pol. is used, as
shown in Figure 1(c). The free-electron-like characteris consistent with the ILB. Since the spectrum by p-pol.
and s-pol. are complementary, dipole selection rulemainly determines the intensity distribution; odd- andeven-parity components are excited by s- and ppolarization, respectively.

Figures 1(d) and 1(e) show the photoelectron
intensity maps on the Fermi energy obtained for s- andp-polarized light. In Fig. 1(d), the photoelectron
intensity has an anisotropy; intensity map along Γ-Kand Γ-K’ direction (shown by dashed lines) is not
identical. On the other hand, in Fig. 1(e), the intensity
distribution is almost isotropic. Since the Dirac state ismainly excited by s-pol., the anisotropy is estimated tobe caused by chirality effect.
In conclusion, it was revealed that the dipole
selection rule has a stronger effect on the intensity
distribution of photoelectron in C6CaC6 than thechirality effect. Reflecting the different symmetry of πbands and ILB, complementary distribution wasobserved in the Fermi contour for the s- and p-polarized
light. The chirality effect appears as the anisotropy in
the Fermi contour of the Dirac cone component.

Ⅲ- 4Fig. 1. (a) Schematic atomic model of Ca-intercalated
bilayer graphene (C6CaC6) on Ca-terminated SiC
substrate. (b)-(c) Band structure of C6CaC6 around Γpoint, obtained by (b) s- and (c) p-polarized light.
Parabolic band is stressed by the dashed guideline. (d),(e) Intensity mapping at Fermi level using (d) s- and(e) p-polarized light. Γ-K and Γ-K’ direction are shownby dashed lines in (d). ARPES measurements were
performed with hν = 33 or 58 eV under T = 6 - 13 K.
[1] Y. Liu et al., Phys. Rev. Lett. 107 (2011) 166803.
[2] C. Bao et al., Phys. Rev. Lett. 126 (2021) 206804.
[3] T. E. Weller et al., Nat. Phys. 1 (2005) 39.
[4] S. Ichinokura et al., ACS Nano 10 (2016) 2761.
[5] H. Toyama et al., ACS Nano 16 (2022) 3582.

127 1 Ⅲ04-

BL3U
Ⅲ -4. Surface,
Interface and Thin Films

BL3U

Elucidation of the Function of Adsorbed Anions
on the Surface of Cobalt Catalysts by Operando Observation
K. Harada1, S. Tsunekawa1, A. Sakai1, M. Nagasaka2 and M. Yoshida1,3
Yamaguchi University, Ube 755-8611, Japan
Institute for Molecular Science, Okazaki 444-8585, Japan
3
Blue Energy Center for SGE Technology (BEST), Ube 755-8611, Japan
1

2

Ⅲ- 4

Recently, hydrogen production by electrolysis ofwater has been attracting attention. In this system,
cobalt catalysts are known to be one of the efficient
oxygen production catalysts [1]. Thus, various
spectroscopic analyses have applied to the catalysts inorder to investigate the physical properties andfunctions. However, the role of anions in the electrolyte
solution is still not fully understood. From thisbackground, in this study, the role of adsorbed anions
on cobalt catalysts was investigated by attenuated totalreflection infrared spectroscopy (ATR-IR) and X-ray
absorption fine structure (XAFS) measurements underoperando conditions.
The electrochemical cell was used with a Pt counterand an Ag/AgCl reference electrode. The cobalt catalyst
was prepared by electrodeposition on Au thin film in asolution containing Co2+ and carbonate anion (Co-Ci
catalyst). Under electrochemical control, the operando
Co K-edge XAFS were measured by fluorescence modein the PF BL-9A, and the operando O K-edge and C Kedge XAFS were measured by transmission mode at
BL3U in the UVSOR synchrotron.
First, we checked the OER activity and found that
Co-Ci functioned as highly efficient water splitting
catalyst. Next, SEM, EDX, and XPS measurements
were also performed to confirm that the catalyst waselectrodeposited on the substrate surface. Furthermore,
the electrolyte solution was exchanged from potassium
carbonate solution (K-Ci) to potassium sulfate solution(K-Si) during monitoring the OER activity, indicatingthat the water splitting activity of the Co-Ci catalyst was
improved in the K-Ci electrolyte solution.
To investigate the electronic state and local structure,
the operando Co K-edge XAFS measurements were
performed with the cobalt carbonate catalyst. EXAFS
analysis showed that the peaks of Co-O and Co-Co
bonds were observed at similar positions compared to
the CoOOH reference sample, suggesting that the
local structure of Co in the catalyst was consistent withthat of CoOOH.
Then, operando O K-edge XAFS was measured, andthe peak of Co(IV) as an active species [2-4] wasobserved at the electrode potential of water splitting
reaction. This indicates the occurrence of high oxidation
number Co in the Co-Ci catalyst at the catalytic active
potential.
Finally, the operando C K-edge XAFS measurements
under the catalytic reaction (Fig. 1) showed thatcarbonate ions were adsorbed on the catalyst surface.

The adsorbed peak was remained even after exchanging
the electrolyte solution from K-Ci to K-Si. In addition,
the same result was obtained in the operando ATR-IR
measurement. Therefore, these results suggest that the
carbonate ions are strongly adsorbed on the Co-Ci
catalyst to maintain the high oxidation number Co as
active site.

Fig. 1. Operando C-K edge XAFS spectra.

[1] W. Kanan, and D. G. Nocera, Science 321 (2008)
1072.
[2] A. M, Ullman, C. N. Brodsky, N. Li, S. L. Zheng,
and D. G. Nocera, J. Am. Chem. Soc. 138 (2016) 4229.
[3] L. P. Wang, and T. Van Voorhis, J. Phys. Chem. Lett.
2 (2011) 2200.
[4] X. Li, and P. E. M. Siegbahn, J. Am. Chem. Soc. 135(2013) 1380.

128 2 Ⅲ04-

BL3B

Ⅲ -4. Surface, Interface and Thin Films

BL3B

Evaluation of Interface Between Sapphire Substrate and UV Emitting Zinc
Aluminate Phosphor Thin Films
H. Kominami1, M. Endo2, T. Kawashima2, N. Sonoda2, K. Inoue2, N. Uesugi2,
K. Nie2, A. Adachi1, R. Ishihara1, Y. Kamoi1, A. Dorokhina3 and S.Kurosawa4,5

Graduate School of Integrated Science and Technology, Shizuoka University, Hamamatsu 432-8651, Japan
2
Faculty of Engineering, Shizuoka University, Hamamatsu 432-8651, Japan
3
Graduate School of Science and Technology, Shizuoka University, Hamamatsu 432-8651, Japan
4
New Industry Creation Hatchery Center (NICHe), Tohoku University, Sendai 980-8579, Japan
5
Faculty of science, Yamagata University, Yamagata 990-8560, Japan

1

The UV light is used for various applications
depending on the wavelength as well as the sterilization
described above. Recently, from the viewpoint ofconsideration to the environment, the mercury free UVemission devices have been demanded for theapplication of catalyst and medical situations. In ourprevious work, it was clarified that ZnAl2O4 phosphor
was suitable for the UV field emission lamp because of
its stability and luminescent property. It shows strong
UV emission peaked around 250 nm which suitable forsterilization.
In this research, ZnAl2O4 thin film layer wereprepared by thermal diffusion of ZnO and sapphire
substrate for new UV devices. To obtain ZnAl2O4 thinfilm with high quality, we explore optimum conditionof thermal annealing.
As a result of XRD of ZnAl2O4 annealed at 970 to1050 °C, it was found that the peaks of (220), (311)
and (333) appeared prominently, and polycrystalline
ZnAl2O4 was formed. Figure 1 shows the full width ofhalf maximum of diffraction peaks and these peakintensity ratio of each phase of ZnAl2O4 annealed at
970 to 1050 °C. Regarding the intensity ratio, theintensity ratio of each phase increased uniformly up to990 °C, but at 1050 °C, the intensity ratio increased
only in (333) and the intensity ratios of (220) and (311)decreased. From this result, it is considered that thegrowth is likely to occur in the orientation of (333)from a temperature exceeding a certain threshold valueof 990 °C or higher.
Next, for ZnAl2O4 (333) that selectively grows on thec-plane sapphire substrate, the orientation of the c-planesapphire substrate and the growth of ZnAl2O4 were
investigated by evaluating the in-plane orientation by Φ
scan measurement. Figure 2 shows a Φ scan of ZnAl2O4(333) annealed at 970 to 1050 °C. Diffraction of (333)with the c-plane sapphire substrate was observed at 60°
intervals. It is considered that both the c-plane sapphire
substrate and (333) have the atomic arrangement of
Aluminum atoms six-fold symmetric, and (333) has
grown to inherit the six-fold symmetry of Aluminum of
the c-plane sapphire substrate.
ZnAl2O4 was prepared at 970 to 1050 °C andevaluated by CL, XRD, SEM and the like. From the
XRD results, it was found that the orientation of

ZnAl2O4 (333) facilitates growth from temperatures
above a certain threshold of 990 °C or higher. From
the results of the Φ scan measurement, it is consideredthat (333) grows so as to inherit the six-fold symmetryof the atomic arrangement of Aluminum in the c-planesapphire substrate.

Ⅲ- 4

Fig. 1 ependence of FWHM and XRD Peak intensityof ZnAl2O4 thin films on annealing temperature.

Fig. 2 Φ-scan of ZnAl2O4 (333) on c-plane sapphire
substrate.

129 3 Ⅲ04-

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Ⅲ -4. Surface,
Interface and Thin Films

BL4U

Application of Atomically-thin Graphene to X-ray Astronomy:
Soft X-ray Transmission Measurements
I. Mitsuishi1, K. Kashiwakura1, Y. Niwa1, T. Ogawa1, M. Hirota1, Y. Tawara1, R. Kitaura2,
P. Solís-Fernández3, K. Kawahara3, H. Ago3, T. Taniguchi4, K. Nomoto4, H. Kodaka4,
T. Ohigashi5, H. Yuzawa5 and K. Tanaka5
Graduate School of Science, Division of Particle and Astrophysical Science, Nagoya University,
Nagoya 464-8602, Japan2
Department of Chemistry, Nagoya University, Nagoya 464-8602, Japan3
Global Innovation Center, Kyushu University, Kasuga 816-8580, Japan
4
Optical Measurement Technology Development Department, R&D Division, USHIO INC.,
Yokohama 225-0004, Japan
5
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan

1>89% corresponding to >97% for single-layer graphene
although the transmission goes down to ~80 % in the C
K-edge structure corresponding to ~95% for singlelayer graphene as shown in Fig. 1 (Mitsuishi et al., in
prep.). To investigate the impact of residual of thecoated material, PMMA, on the free-standing graphene
structure used in our fabrication process, we obtainedtransmission around the O K-edge structure even though
the coated material was removed by using acetone. The
observed transmission in 520—564 eV ranges from 95
to 98% and thus no strong contamination was found. To
estimate the transmission more accurately, a systematic
error such as a variation in the beam intensity should betaken into account in the near future.
Experimental setup

SEM imagefor free-standing 5-layer graphene

X - ray1

20mm

Transmission for 5-layer graphene(Mitsuishi et al., in prep.)
1-layer graphene (estimated)

Transmission

Ⅲ- 4Thin films have been used in a variety of academic
fields including astronomy. In X-ray astronomy,
because X-rays are absorbed by the atmosphere of the
Earth, balloons, rockets, and satellites are often used toobserve X-rays from astronomical objects such as black
holes, neutron stars, clusters of galaxies, and so on. Thinfilm devices have often been used in payloads ofprevious missions and playing a key role as, e.g., opticaland contamination blocking filters and thermal shields[e.g., 1,2]. For such thin film devices, tolerance forsevere launch and space environments and hightransmission for more efficient use of limited observing
time are required at the same time. Polyimide films haveoften been adopted because of relatively higher
mechanical strength and heat tolerance in plastic
materials. However, there is still room for improvement
especially in transmission of a soft energy band below
1 keV. Thus, we have proposed to make use of graphene
which is an atomically-thin material but has excellent
mechanical and thermal properties at the same time. Ouridea is to apply graphene to thin film devices in X-ray
astronomy for the first time.
As a first step, we need to conduct X-ray transmission
measurements to verify whether the transmission ofgraphene films especially in a soft energy band isactually high or not as expected because, as far as weknow, no observed data is available except around 300
eV corresponding to the C K-edge structure. We
prepared 5-layer free-standing graphene on a quartz
substrate with a thickness of 200 µm with through holes
with a diameter of 10 µm. To measure the number of Xray photons with/without the 5-layer free-standing
graphene collected by the Fresnel zone plate correctly,
a taper structure with a taper angle of 30 degrees was
prepared for each free-standing structure. The sample inthe vacuum chamber and a close-up SEM image of thefree-standing 5-layer graphene are shown in Fig. 1.
Consequently, we obtained the transmission in 100, 140,
180, 220, 260, 340, 380, 420, 460, 500 eV, and the C Kedge structure between 280 and 320 eV in details
successfully and confirmed that the observed
transmission is very high as expected on the order of

0.9

5-layer graphene
0.8

Quartz wafer with free- 280
standing 5-layer graphene

300

Energy [eV]320

Fig. 1. Experimental setup with our sample and an
example of the observed soft X-ray transmission curve.

[1] P.J. Serlemitos et al., Publ. Astron. Soc. Japan 47(1995) 105-114.
[2] P.J. Serlemitos et al., Publ. Astron. Soc. Japan 59(2007) S9-S21.

130 4 Ⅲ04-

BL4B

Ⅲ -4. Surface, Interface and Thin Films

BL4B

Annealing Effect on the Vacuum Ultraviolet Transmission Spectrum of
Amorphous Selenium
K. Hayashi

Department of Electrical, Electronic and Computer Engineering, Gifu University, Gifu 501-1193, JapanThe decrease in the photoconductivity and the dark
conductivity by long exposure to bandgap light havebeen observed in hydrogenated amorphous silicon [1]and amorphous chalcogenide materials [2]. This effectis usually called photodegradation and is explained in
the creation of light-induced metastable defects (LIMD).
Many models have been proposed for LIMD creation,
but details of the mechanism for LIMD creation in thesematerials are still not clear. Recently, we have observedchanges in photoconductivity in amorphous chalcogenide
materials that cannot be explained by the creation of
LIMD. The x-ray diffraction and the volume change ofthe films before and after irradiation of bandgap lightsuggest that the photoinduced phenomena is due to achange of the local structure of the amorphous network.
Understanding the physical mechanism underlying
metastability is one of the important fundamental
problems related to these materials. In the previous
reports, we reported the photoinduced effects on thevacuum ultraviolet (VUV) transmission spectrum ofamorphous arsenic triselenide by the irradiation of the
bandgap light. In this report, we study the annealing
effect on the VUV transmission spectrum of amorphousselenium.
Sample used for the measurement of the VUVtransmission spectra was amorphous Se (a-Se) thin film
prepared onto thin aluminum film by conventional
evaporation technique. The sample thickness was about
180nm. The aluminum film of the thickness of 200 nm
was used to eliminate the higher order light from themonochromator in the VUV region. These measurements
were carried out at room temperature on the BL4B
beam line of UVSOR. The spectrum was measured byusing the silicon photodiode as a detector. Two pinholesof 1.5mm in a diameter were inserted between the
monochromator and sample to remove stray light. The
intensity of the VUV light was monitored by measuring
the TPEY of a gold mesh. The positions of the corelevels for the samples were calibrated by referencing to
the 2p core level absorption of the aluminum film.
Figure 1 shows annealing effect on the VUVtransmission spectra of amorphous Se thin film. The
VUV transmission spectrum of amorphous As2Se3 isalso shown on the figure for reference. Annealing effecton the VUV transmission spectrum was investigated byannealing the amorphous Se with 353 K for 1 hour.
Amorphous Se is thought to crystallize (polycrystalline)
at this annealing temperature. As shown in the figure,each spectrum is very broad and multiple shoulders areobserved. The absorption spectrum observed in theamorphous Se is roughly consistent with the previous

report [3]. Main absorption peaks around 22nm
corresponds to the 3d core level of Se atom. Although
the wavelength resolutions in the spectral
measurements are all the same, the spin-orbit splittingof the 3d5/2 and 3d3/2 level of Se atom is clearly resolvedin amorphous As2Se3, while they are not clearly
resolved in as-deposited amorphous Se and annealed
amorphous Se. When amorphous Se crystallizes byannealing, it can be seen that the broad peak around 20
nm was composed of about three absorption peaks. It is
not clear about the origin of broad spectra and several
peaks. I think that these origins are related to the local
structures of the amorphous network. The detailed
experiments and analysis will be done in the next step.
More detailed experiments are necessary to clarify theorigin of the VUV transmission spectra.

Ⅲ- 4Fig. 1. Annealing effect on the VUV transmission
spectra of a-Se thin film.

[1] D. L. Staebler and C. R. Wronski, Appl. Phys. Lett.
31 (1977) 292.
[2]K. Shimakawa, S. Inami, and S. R. Elliott, Phys. Rev.
B 42 (1990) 11857.
[3] J. Bordas and J. B. West, Phil. Mag. 34 (1976) 501.

131 5 Ⅲ04-

BL4BInterface and Thin Films
Ⅲ -4. Surface,

BL4B

Magnetic Properties of CoPc/γ’-Fe4N Organic-inorganic Hybrid Interface
T. Miyamachi1,2, H. Ono1, Y. Umeda1, K. Yamamoto3,4, O. Ishiyama3,4, T. Yokoyama3,4and M. Mizuguchi1,2Department of Materials Science and Engineering, Nagoya University, Nagoya 464-8603, Japan.
Institute of Materials and Systems for Sustainability (IMaSS), Nagoya University, Nagoya 464-8601, Japan.
3
Institute for Molecular Science, Okazaki 444-8585, Japan
4
The Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan
1

2

Ⅲ- 4

Organic materials are expected to be useful to
spintronics devices due to their low spin current
dissipation derived from weak spin-orbit interaction.
In particular, an organic-inorganic hybrid interface has
attracted much attention because its interface spin state
can be controlled via the proximity effect. Spindependent electron transport properties of organicinorganic hybrid system strongly depend on thedomain size of organic molecular films, defect density
and adsorption geometry of organic molecules. Thus,
understanding structural, electronic and magnetic
properties of the organic-inorganic interface on thelevel of single molecules is essential for realizing
molecular spintronics devices. However, microscopic
details of the hybrid interface have not been clarified
so far.
In this study, we focus on fabricating organicinorganic hybrid films with structurally controlledinterface on the level of single molecules andinvestigating their intrinsic electronic and magnetic
properties. For this purpose, ferromagnetic iron nitride
atomic layers with γ’-Fe4N stoichiometry were chosen
as an inorganic material, which uniformly grow andshow high surface quality on the atomic scale [1,2].
Molecular layers composed of planer cobalt
phthalocyanine (CoPc) were chosen as an organic
material. Structural, electronic and magnetic propertiesof the hybrid interface composed of CoPc with the
thickness of 1, 2 and 3 molecular layers and a bilayer γ’Fe4N were investigated by scanning tunneling microscopy(STM), low energy electron diffraction (LEED) and xray absorption spectroscopy/magnetic circular dichroism(XAS/XMCD).
A bilayer γ’-Fe4N was prepared by iron deposition on
Cu (001) with N+ ion bombardment and subsequentannealing at 620 K. Then, CoPc/γ’-Fe4N hybrid thinfilms were fabricated by depositing CoPc on the γ’Fe4N at room temperature. In combination with resultsof STM and LEED, the impact of the thickness of CoPc
layers on the interfacial magnetic state was investigated
by XAS/XMCD.
XAS/XMCD measurements were performed at
BL4B in UVSOR by total electron yield mode at B = 0- ± 5 T and T = 7.3 K. The XMCD spectra are obtainedat the normal (NI: θ = 0°) and the grazing (GI: θ = 55°)
geometries by detecting μ+ – μ–, where μ+ (μ–) denotes
the XAS recorded at Fe and Co L adsorption edges withthe photon helicity parallel (antiparallel) to the sample
magnetization. Note that θ is the angle between thesample normal and the incident x-ray [3].
We find that the Fe orbital magnetic moment of thebilayer γ’-Fe4N evaluated by XMCD sum rule analysis
changes with increasing thickness of the CoPc layer.
The difference between the out-of-plane and in-plane Fe
orbital magnetic moment, which is proportional to themagnetic anisotropy [4], is the largest when about one
CoPc layer is deposited on the γ’-Fe4N and it decreases
with further increasing thickness of the CoPc layer. The
results suggest the perpendicular magnetic anisotropyof the γ’-Fe4N is enhanced by the magnetic couplingwith CoPc molecules at the interface. STM and LEED
observations reveal that the presence of the CoPc
overlayers increases the surface roughness, which mightin turn decrease the perpendicular magnetic anisotropyof the γ’-Fe4N arising from the formation of the CoPc/γ’Fe4N hybrid interface through the intermolecularinteraction between CoPc layers.

[1] Y. Takahashi et al., Phys. Rev. Lett. 116 (2016)056802.
[2] Y. Takahashi et al., Phys. Rev. B 95 (2017) 224417.
[3] S. Nakashima et al., Adv. Funct. Mater. 29 (2019)1804594.
[4] P. Bruno, Phys. Rev. B 39 (1989) 865.

132 6 Ⅲ04-

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Ⅲ -4. Surface, Interface and Thin Films

BL4B

Enhancement of the Perpendicular Magnetic Anisotropyin N-surfactant Assisted FeCo Ordered Alloy Thin Films
T. Miyamachi1,2, Y. Umeda1, H. Ono1, K. Yamamoto3,4, O. Ishiyama3,4, T. Yokoyama3,4and M. Mizuguchi1,22

1Department of Materials Science and Engineering, Nagoya University, Nagoya 464-8603, Japan.
Institute of Materials and Systems for Sustainability (IMaSS), Nagoya University, Nagoya 464-8601, Japan.
3
Institute for Molecular Science, Okazaki 444-8585, Japan
4
The Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan

Skyrmions are nano-scale magnetic vortex structures,
attracting great attention as a promising candidate ofnext-generation information storage devices due to their
expected high magnetic stability and low critical current
density for motion. Skyrmions can emerge in magnetic
thin film hetero structures with the ferromagnetic/heavy
metal interface. Since Dzyaloshinsky–Moriya interaction
induced by 3d-5d hybridization effects is the driving
force of the emergence of skyrmions in this system, thestrict control of structural, electronic and magnetic
properties of the interface in magnetic thin film hetero
structures is quite important. Recently, we haverevealed that large-area and atomically uniform ironnitride atomic layers with γ’-Fe4N stoichiometry can begrown on Cu(001) [1]. Thus, in this work, we intend togrow 5d heavy metal thin films on γ’-Fe4N atomic
layers and fabricate the high quality 3d-5d heterointerface
towards developing skyrmions-based novel magnetic
structures. For this purpose, we first grow a monatomic
layer of Co onto bilayer γ’-Fe4N and investigate theimpact of the quality of 3d-3d heterointerface onelectronic and magnetic properties of the system by low
energy electron diffraction (LEED) and x-ray
absorption spectroscopy/magnetic circular dichroism(XAS/XMCD).
To grow a bilayer γ’-Fe4N, N+ ion bombardment was
first conducted with an incident energy of 500 eV onto
Cu substrate and iron was additionally deposited atroom temperature in ultra-high vacuum. The bilayer γ’Fe4N was obtained by subsequent annealing at ~620 K.
Appropriate growth conditions about the deposition
amount of iron and annealing temperature wereprechecked by atomically resolved surface
characterizations using scanning tunneling microscopy(STM) [2]. Then, the low temperature deposition of amonatomic layer of Co at - 170 K was performed tofabricate Co-γ’-Fe4N magnetic thin film hetero
structures. The sample was post-annealed at 300, 570
and 670 K and the annealing temperature dependenceof electronic and magnetic properties was investigated
by XAS/XMCD. XAS/XMCD measurements were
performed at BL4B in UVSOR by total electron yieldmode at B = 0 - ± 5 T and T = 7.9 K. The XMCD spectra
are obtained at the normal (NI: θ = 0°) and the grazing(GI: θ = 55°) geometries. Note that θ is the angle
between the sample normal and the incident x-ray.

Element specific magnetization curves were also
recorded by plotting the L3/L2 Fe and Co XAS
intensities as a function of the magnetic field.
The XMCD signal of the bilayer γ’-Fe4N is greater in
the GI geometry than NI geometry, which reveals its
strong in-plane magnetic anisotropy as previously
reported [1]. Adding one monolayer of Co activates thenitrogen surfactant effect [3,4], which leads to theformation of CoN in the topmost layer. Accordingly, we
find from Fe magnetization curves that the out-of-planemagnetization of the Fe layer is relatively increased.
The perpendicular magnetic anisotropy of the Fe layer
is further enhanced by annealing at 570 K. However, atannealing temperature of 670 K, the decrease in thecoercivity of the Fe layer is overserved. Taking theannealing temperature dependence of the LEED pattern
into consideration, the enhancement of the out-of-planemagnetization could be caused by the improvedordering of the Co/Fe interface up to annealing
temperatures of 570 K. At 670 K, surface N atoms start
to desorb, which induces the interdiffusion of interfacial
Co and Fe atoms and consequently lowers the coercivity.

[1] Y. Takahashi et al., Phys. Rev. B 95 (2017) 224417.
[2] Y. Takahashi et al., Phys. Rev. Lett. 116 (2016)056802.
[3] K. Kawaguchi et al., Phys. Rev. Materials 4 (2020)
054403.
[4] K. Kawaguchi et al., Jpn. J. Appl. Phys. (accepted).

133 7 Ⅲ04-

Ⅲ- 4

BL5U
Ⅲ -4. Surface,
Interface and Thin Films

BL5U

ARPES from Si{111} Facet Surfaces on Three-dimensional Lined
Structures on Si(001) Substrates
K. Hattori1, L. N. Pamasi1, Y. Sakai1, H. Yang1, T. Shimizu1, Y. Ida3, W. Imayama3,
S. Tanaka2, A. N. Hattori2, S. Suga2 and K. Tanaka3
Nara Institute of Science and Technology, Ikoma 630-0192, Japan
2
SANKEN, Osaka University, Ibaraki, 567-0047, Japan
3
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan1

Ⅲ- 4

Our information society has required highly
densitized devices like 3D FET, which can break the
restriction of miniaturizing 2D planar-type devices. To
improve the specification (e.g., carrier mobility) of 3D
devices, it is indispensable the control of 3D structuresurfaces which are carrier passing region.
So far, our group have successfully created 3D Si
surfaces by the combination of lithography and surface
treatment techniques [1-7]: SEM, RHEED, LEED, or
STM evaluations for lined or pyramidal structureswith {111}, {110}, or {100} side/facet surfaces on(111), (110), or (001) substrates. In the beam time in
2021 FY, we focused electronic band investigations for
3D-Si surfaces, which promise side/facet-wall bandengineering.
Figure 1 shows brief results for a 3D-Si lined
structure (4 μm period) with {111} facet surfaces on a(001) substrate: (a) SEM image and (c) LEED pattern
after the flash annealing in UHV. The LEED patterns
clearly indicated 7� 7 reconstruction on �111� and�1� 1� 1� facet surfaces; the 7�7 spots move in right orleft directions.
ARPES from the area including �13 �1� 1� 1� facetsurfaces in geometry A (Fig. 1(d), note �111� isinvisible) showed clear bulk-projected band dispersion
and 7�7 surface bands: S1-S3, which guarantees wellcontrolled electronic states on the facet surfaces.
ARPES from �111� mainly in geometry B (𝜃𝜃�� = 30°
and 𝜃𝜃� = 27.5 ° ) showed band dispersions at 𝜃𝜃� ≲35.3° assigned from �111� and also dispersions
below the �111� horizontal at 𝜃𝜃� ≳ 35.3° which
could be assigned from glancingly radiated �1� 1� 1� orthe edge regions.
[1] A.N. Hattori, K. Hattori et al., Surf. Sci. 644 (2016)
86.
[2] A.N. Hattori, K. Hattori et al., Appl. Phys. Express
9 (2016) 085501.
[3]H. Yang, A.N. Hattori, K. Hattori et al., Jpn. J. Appl.
Phys. 56 (2017) 111301.
[4] S. Takemoto, A.N. Hattori, K. Hattori et al., Jpn. J.
Appl. Phys. 57 (2018) 090303.
[5] A.N. Hattori and K. Hattori, 21st Century Surface
Science (IntechOpen, London, 2020).
[6] A. Irmikimov, A.N. Hattori, K. Hattori, et al., ACS
Cryst. Growth Des. 21 (2021) 946.
[7] S. Nakatsuka, T. Abukawa, A.N. Hattori, K. Hattori
et al., e-J. Surf. Sci. NanoTechnol. 19 (2021) 13.

Fig. 1. (a) SEM image, (b) sample schematics on
holder, (c) LEED pattern (𝐸𝐸� = 80 eV), (d) geometry ofincident light (pink arrow) and electron emission(green line and fan-shaped purple) to sample, and (e)ARPES ( ℎ𝜈𝜈 = 60 eV, p-polarization; 𝜙𝜙 = 50 μm ,acceptance angle� �15°, light-analyzer angle= 57.5°)
in geometry A at 𝜃𝜃�� = 55° (𝜃𝜃� = 2.5°), for 3D facetlined structures with Si{111} facet surfaces on Si(001)substrates.

134 8 Ⅲ04-

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Ⅲ -4. Surface, Interface and Thin Films

BL5U

Electronic Structure of K Adsorbed SmS Surface
T. Nakamura1,2, T. Nakaya2, H. Sugihara2, K. Tanaka3,
K. Imura4, H. S. Suzuki5, N. K. Sato4 and S. Kimura1,2,3

Graduate School of Frontier Biosciences, Osaka University, Suita 565-0871, Japan
Department of Physics, Graduate School of Science, Osaka University, Toyonaka 560-0043, Japan
3
Institute for Molecular Science, Okazaki 444-8585, Japan
4
Department of Physics, Graduate School of Science, Nagoya University, Nagoya 464-8602, Japan
5
Institute for Solid State Physics, The University of Tokyo, Kashiwa 277-8581, Japan
1

2

Samarium mono-sulfide (SmS) is a typical valencefluctuation material [1]. At ambient pressure, SmS is asemiconductor with an indirect bandgap of about 0.1
eV, and its color is black [2]. The electrical properties
change to metallic above a critical pressure of 0.65
GPa. Although the pressure-induced phase transition
was discovered over 50 years ago [1], the origin of thephase transition is still under debate. Recently, a phasetransition like the pressure-induced one has beenreported due to two different types of perturbations:light irradiation and current injection [3,4]. These
perturbations are commonly expected to increasecarriers, but the detailed electronic states after carrier
doping have not been clarified yet.
Alkali metal adsorption on crystal surfaces is widelyused as a typical method to investigate the effect ofcarrier injection into a material. Due to the chargetransfer of the free-electron-like outermost electrons in
the alkali metal to SmS, a carrier-doped SmS surface
can be realized. In this work, we have studied thechange of the electronic structure by potassium (K)doping on a SmS surface by synchrotron-based ARPES.
A high-quality single-crystalline SmS was grown by
the vertical Bridgman method in a high-frequency

induction furnace. The clean SmS surface wasobtained by cleaving in-situ in an ultra-high vacuum
chamber. K atoms were evaporated from the welldegassed alkali metal dispenser (SAES-Getters) atroom temperature (RT).
Figure 1(a) shows the ARPES intensity plot of thepristine-SmS along the Γ� - �
X line of the surface
Brillouin zone taken with 60-eV photons. Flat Sm2+ 4f 5
multiplet structure and dispersive S 3p bands wereobserved. After the K deposition as shown in Fig. 1(b),the band dispersion of the Sm 4f states was changed
without a higher binding energy shift due to the naturalelectron doping. These results suggest that the Kadsorption on SmS caused a deformation of the band
structure, which cannot be explained as a simple rigid
band shift model due to electron doping.
[1] A. Jayaraman et al., Phys. Rev. Lett. 25 (1970) 1430.
[2] K. Matsubayashi et al., J. Phys. Soc. Jpn. 76 (2007)
064601.
[3] R. Kitagawa et al., Appl. Phys. Lett. 82 (2003) 3641.
[4] H. Ando et al., JPS Conf. Proc. 30 (2020) 011132.

� with 60-eV photons at
Fig. 1. ARPES intensity plots of (a) pristine SmS and (b) K-adsorbed SmS along Γ�-X
room temperature.

135 9 Ⅲ04-

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Ⅲ -4. Surface,
Interface and Thin Films

BL5U

Explorations for Spontaneously Formed Excitons in Narrow-gap
Semiconductors and Semimetals
K. Fukutani1,2, M. Murakami3, C.I. Kwon4,5, J. S. Kim4,5, K. Tanaka1,2, S. Kera1,2,3

Institute for Molecular Science, Okazaki 444-8585, JapanThe Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan
3
Graduate School of Science and Engineering, Chiba University, Chiba 263-8522, Japan
4
Center for Artificial Low-Dimensional Electronic Systems, Institute for Basic Science, Pohang, Korea
5
Pohang University of Science and Technology, Pohang, Korea
1

2

Ⅲ- 4

Excitons are bound pair of an electron and a hole,conventionally produced transiently by irradiation oflight on semiconductors, and is one of the mostfundamental quasiparticles in solids and molecularmaterials that play central roles in various quantum
devices, such as photovoltaic cells, light emitting diodes
and photodetectors.
In recent years, a new exotic phase of matter called
an excitonic insulator has garnered much attentions. In
the excitonic insulator phase, at sufficiently low
temperature, the electrons and holes are spontaneously
bound to form an excitons and undergo quantum
condensation.
Among the various candidate materials for excitonic
insulator, Ta2NiSe5 is particularly suitable for theexperimental investigations as it exhibits a direct band
gap and the excitonic insulator transition accompanies
only a minor structural distortion, which preserves theperiodicity of the material. For this relative simplicity,
Ta2NiSe5 has been investigated extensively in the past
decade by various experimental methods [1] and it is
widely conceived to be a Bose-Einstein condensation(BEC)-type excitonic insulator.
Of particular interest in the BEC-type excitonic
insulator is the theoretical prediction of the intermediatephase called “preformed exciton phase”, which isbelieved to appear between the excitonic insulator andthe normal phases (see Fig. 1) [2]. In the preformed
exciton phase, the magnitude of the bandgap is smallenough (i.e., the free carrier screening is small enough)to allow for the bound state for the electrons and holes,
yet the temperature is too high for these spontaneously
formed excitons to undergo the Bose-Einsteincondensation. Therefore, this particular region of thephase diagram supports the existence of finite numberof excitons in equilibrium. In our recent study [3], thedirect photoemission signal from these spontaneously
formed excitons have been detected and long-standing
theoretical prediction has been confirmed. However, thedetailed formation mechanism of such excitons is still
elusive due to the lack of experimental data for thisparticular phase of excitonic insulator materials.
Thus, in order to pin down the origin of these
spontaneously formed excitons, we are performing aseries of angle-resolved photoemission spectroscopy(ARPES) experiments at BL5U for the chalcogensubstituted compounds Ta2Ni(Se1-xSx)5 for various
compositions x. In the experiments, the freshly cleaved

samples of Ta2Ni(Se1-xSx)5 have been measured toreveal their band structures as well as to explore forthe photoemission signals from the spontaneously
formed excitons as a function of temperature, photon
energy as well as the light polarizations.
A representative result of the ARPES intensity plot isshown in Fig. 2. It can be seen that the photoemission
signal from excitons, observed in Ta2NiSe5 [3] is also
observed for the S-substituted compounds.

Fig. 1. Theoretical phase diagram of excitonic insulators.

Fig. 2. ARPES intensity plot for chalcogen-substituted
excitonic insulator Ta2Ni(Se1-xSx)5.

[1] Y. Wakisaka et al., Phys. Rev. Lett. 102 (2009)026402; Y.F. Lu et al., Nat. Commun. 8 (2017) 14408.
[2] F.X. Bronold et al., Phys. Rev. B 74 (2006) 165107.
[3] K. Fukutani et al., Nat. Phys. 17 (2021) 1024.

13610 Ⅲ04-

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Ⅲ -4. Surface, Interface and Thin Films

BL5B

X-ray Absorption Spectroscopy Measurements of Au/Fe/MgO Sandwich
Structure Sample for Study of Soft X-ray Second Harmonic Generation
T. Sumi1, M. Horio1, X. Zhang1, T. Kato2 and I. Matsuda1,3

2

1Institute for Solid State Physics, The University of Tokyo, Kashiwa 277-8581, Japan
Institute of Materials and Systems for Sustainability, Nagoya University, Nagoya 464-8603, Japan
3
Trans-scale Quantum Science Institute, The University of Tokyo, Tokyo 113-0033, Japan

Second harmonic generation (SHG), which is aphenomenon that occurs by the interaction between
light and a system where the inversion symmetry is
broken, has been used not only to convert light tohigher frequencies but also to investigate electronic
states of molecules at the systems in the visible region.
After the construction of X-ray Free Electron Laser(XFEL) such as Pring-8 Angstrom Compact freeelectron LAser (SACLA), we have been developing
SHG methods in the range of soft X ray, and applied
to GaFeO3 [1], LiNbO3 [2], LiOsO3 [3], and GaAs [4].
By setting the incident energy to the inner-shell corelevel, SHG acquires element selectivity by inner-coreexcitation resonance. Although this technique is usefulto reveal the electronic states of the targeted atoms at
surfaces/interfaces, there is no report for the interface
SHG.
In this research, at UVSOR BL5B, we conducted Xray absorption spectroscopy for a Fe film sandwichedby films of Au and MgO to grasp the possibility of theoccurrence of soft X-ray SHG before observing it. We
synthesized the sample by ultrahigh vacuum molecularbeam epitaxy method. The sandwich structure of
Au/Fe/MgO was repeated 4 times. The structure of thesample is [Au (2 nm)/Fe (2 nm)/MgO (2 nm)]4/MgO(001,substrate) (Fig. 1). The sample was placed perpendicular
to the incident beam, and the drain current was measured.
Figure 2 shows a XAS spectrum around the Fe Medge. The drain current, I, was normalized by incident
intensity, I0, measured by the Au mesh. The result shows
Fe M-edge (53 eV) absorption peak appears. This meansthat the Fe M-edge dipole transition is allowed. To
investigate the transition around the SHG energy (106eV), the drain current was measured around that energy
without the Au mesh to prevent the effect of the mesh(Fig. 3). The peak appears around 106 eV. These results
suggest that the dipole transitions in the SHG process
starting from Fe M-shell are allowed.
In conclusion, we investigated the electric dipole
transition for the Au/Fe/MgO sandwich structuresample by XAS and found the possibility of the SHG
process starting from the Fe M shell (hν = 53 eV). It is
expected that SHG originating from the interfaces isavailable. Furthermore, it is possible to achieve soft Xray magnetization-induced SHG (MSHG) by applying
a magnetic field to this sample because it hasperpendicular magnetization anisotropy (PMA).

Fig. 1. Structure of the [Au/Fe/MgO]4 / MgO(001)sandwich structure sample.

Fig. 2. XAS spectrum for the sandwich structuresample around Fe M-edge.

Fig. 3. Drain current of the sandwich structure sample
without (blue) and with (red) the Au mesh.
[1] Sh. Yamamoto et al., Phys. Rev. Lett. 120 (2018)
223902.
[2] E. Berger et al., Nano Lett. 21 (2021) 6095.
[3] C. B. Uzundal et al., Phys. Rev. Lett. 127 (2021)
237402.
[4] T. Sumi et al., e-J. Surf. Sci. Nanotech. (2022)(accepted).

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Ⅲ -4. Surface,
Interface and Thin Films

BL6U

Bromine Doping to Perylene Monolayer on Au(110): Photoelectron
Momentum Microscopy
O. Endo1,3, F, Matsui2, S. Kera2, W. -J. Chun3, M. Nakamura4, K. Amemiya5 and H. Ozaki1

Department of Organic and Polymer Materials Chemistry, Faculty of Engineering, Tokyo University ofAgriculture and Technology, Koganei 184-8588, Japan
2
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
3
Graduate School of Arts and Sciences, International Christian University, Mitaka 181-8585, Japan
4
Department of Applied Chemistry and Biotechnology, Faculty of Engineering, Chiba University,
Chiba 263-8522, Japan
5
Photon Factory, High Energy Accelerator Research Organization (KEK-PF), Institute of Materials Structure
Science (IMSS), Tsukuba 305-0801, Japan1

Ⅲ- 4

Energy level alignment at organic-metal interface is
one of the important topics in the field of organic
electronics [1]. The HOMO and LUMO levels oforganic molecules shift upon adsorption as a result of
the work function change due to the formation of aninterfacial dipole. This causes the change of the charge
injection barrier from the metal electrode, which
affects the efficiency of the organic devices. Recently,
doping of organic semiconductors is re-focused to
improve the conductivity [2]. The doping process inorganic semiconductors is the charge transfer between
the molecules, and two representative mechanisms areproposed: one is the integer charge transfer, or
ionization, and the other is the formation of chargetransfer complex [2]. In either case, the energy levelsof the doped molecule are altered from those of theoriginal HOMO or LUMO, because of the electrostatic
effect derived from the doped charge, or the orbital rehybridization. Therefore, the energy level alignment of
the doped molecules at the metal interface is necessary
to be elucidated. In this study, we have observed theelectronic structure of perylene molecules on theAu(110) surface and the effect of bromine doping byangle resolved photoelectron spectroscopy (ARPES)
and X-ray photoelectron spectroscopy (XPS) using
momentum microscope, which has recently been
introduced at BL6U.
Figure 1(a) shows the ARPES results of the perylene
monolayer on the Au(110)-(1x2) surface, which was
obtained at Eb = 1.5 eV at the surface normal direction.
The photoelectron pattern simulated for the HOMO ofthe perylene molecule at the normal direction withrespect to the molecular plane is shown in Fig. 1(c),right panel, which was obtained by the plane wave
approximation. This four-fold pattern is changed to a
two-fold one for the ±18° off-nomral direction, as
shown in Fig. 1(b). The pattern resemblance for Fig.
1(a) and 1(b) indicates that the molecular plane is tilted±18° with respect to the surface normal. The tilted
molecular orientation is in accordance with the resultsof X-ray absorption spectroscopy (XAS), and thescanning tunneling microscopy [3]. Figure 1(d) depicts
the structural model of perylene on Au(110)-(1x2).
Bromine molecules doped to the perylene monolayer

penetrate into the monolayer and adsorbed dissociatively
on the Au(110) surface. This was confirmed by the Br3d XPS spectra. Upon bromine penetration, theorientation of the perylene molecules become random.
Therefore, the characteristic ARPES pattern of the
HOMO electrons disappears. The XAS results indicatesthat the perylene molecules are cationized uponbromine doping, because of the charge transfer from theperylene to the Au surface mediated by the bromine
layer. The HOMO level exceeds the Fermi level as aresult of the upward energy shift of the perylene MOs
induced by the bromine layer, and hence, part of the
HOMO electron is transferred. The energy shift was
confirmed by the C-1s XPS spectra.

Fig. 1. (a) Momentum map of perylene/Au(110) at Eb= 1.5 eV. (b) Simulated photoelectron distribution for
perylene molecule tilted ±18° along the short axis. (c)Orbital distribution of perylene HOMO and thesimulated photoelectron distribution at the normal
direction with respect to the molecular plane. (d)Structural model of perylene on Au(110).
[1] H. Ishii, et al., Adv. Mater. 11 (1999) 605.
[2] I. Salzmann, et al., J Electron Spectros Relat
Phenomena 204 (2015) 208.
[3] L. Gross, et al., Org. Electron. 3 (2002) 1.

13812 Ⅲ04-

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Ⅲ -4. Surface, Interface and Thin Films

BL6U

High-resolution Photoelectron Momentum Microscope Study on theElectronic Structure of Charge-density-wave Material
K. Fukutani1,2, S. Tanaka3, F. Matsui1,2 and S. Kera1,2,4

Institute for Molecular Science, Okazaki 444-8585, JapanThe Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan
3
Sanken, Osaka University, Ibaraki 567-0047, Japan.
4
Graduate School of Science and Engineering, Chiba University, Chiba 263-8522, Japan1

2

Among various critical phenomena in solids, charge
density wave (CDW) is one of the widely observed
phase transitions, which induces deformation of lattice
periodicity as well as of the electronic density. The
prototypical examples of such CDW are found in manyof the transition metal dichalcogenides (TMDCs),
which exhibit the wide range of periodicities upon thephase transitions, including commensurate andincommensurate CDWs [1].
On the other hand, despite the ubiquity of CDWs
and the decades-long intensive research efforts, aimed
for revealing their microscopic mechanisms, there isno clear consensus on their driving forces.
Recently, the roles of dimensionalities on theproperties of TMDC materials and their CDWs haveattracted much attentions. In particular, in the twodimensional limit (i.e., a single monolayer), some
TMDC materials are found to behave in drasticallydifferent manners, as can be seen in two-dimensional
ferromagnetism of VSe2 [2], the suppression of CDW
in TaS2 [3], and the enhancement of CDW in NbSe2[4], to name a few. These recent observations showthat the careful studies of the dimensionality effects
can provide key insights in resolving the long-standing
mysteries of the origin of CDW transitions.
Among such TMDC materials, the series of titanium
dichalcogenides, TiX2 (X = S, Se, Te) present particularlyinteresting trends in CDW properties. While in the bulk
form, only TiSe2 exhibits CDW, in the two-dimensional
limit, CDW with the same periodicity emerges for TiTe2[5], suggesting the role of dimensionality in theemergence of CDW.
However, it has been reported that the choice of
substrate affects significantly the CDW order [6]. Thisis most naturally attributed to the interactions between
the monolayer TiTe2 and the substrate. In other words,
while the dimensionality is a critical factor for CDW
formation, the degree to which the monolayer-substrateinteraction breaks the “pure” two-dimensionality of TiTe2
is a critical issue that must be systematically investigated.
In this project, we attempt to tune the dimensionality
quasi-continuously by inserting the intercalation layer
with various atomic thicknesses near the surface of bulk
TiTe2, whereby gradually “lifting up” the two-dimensional
layer to investigate the respective electronic structures.
For this purpose, photoelectron momentum microscope(PMM) is an ideal instrument, which can efficiently
identify the periodicity and the topology of the Fermi
surface structure in wide momentum range. In the firstphase of this project, we have performed the highresolution PMM measurements on pristine TiTe2.
Combined with the use of space-resolved mode, thesurface of high crystallinity can be readily found andthe example of the obtained spectra is shown in Fig. 1.
The experiments were performed with photon energy
as well as polarization dependence, and the obtained
set of data are expected to yield detailed informationon the three-dimensional (kx, ky, kz) electronic structures
as well as their orbital textures.

Ⅲ- 4Fig. 1. (a) Fermi surface intensity image and (b) band
structure mapping of TiTe2 obtained at hv = 52 eV and
T = 50 K with PMM at BL6U.

[1] K. Rossnagel, J. Phys.: Condens. Matter 23 (2011)
213001.
[2] M. Bonilla et al., Nat. Nanotechnol. 13 (2018) 289.
[3]C. E. Sanders et al., Phys. Rev. B 94 (2016) 081404(R).
[4] X. Xi et al., Nat. Nanotechnol. 10 (2015) 765.
[5] P. Chen et al., Nat. Commun. 8 (2017) 516.
[6] M.-K. Lin et al., Phys. Rev. Lett. 125 (2020) 176405.

13913 Ⅲ04-

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Ⅲ -4. Surface,
Interface and Thin Films

BL6U

Twin-domain Boundary and Monoatomic Step of Graphite Surface
Imaged by Photoelectron Momentum Microscopy
F. Matsui1,2, Y. Okano1, H. Matsuda1, T. Yano1, E. Nakamura1, S. Kera1,2 and S. Suga3,4
1

UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, JapanThe Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan
3
SANKEN, Osaka University, Suita, Osaka 567-0047, Japan
4
Forschungszentrum Jülich, Germany

2

The photoelectron momentum microscope is an
instrument that combines a photoelectron microscopewith a projection-type electron energy analyzer toenable both μm-scale valence band mapping andmomentum-selective photoelectron microscopy [1-3].
Using these methods, we measured the local electronic
structure of graphite crystal surfaces.

Ⅲ- 4Fig. 1. μm-scale valence band mapping and momentum
selective photoelectron microscopy of graphite surface.

The cleaved graphite surface is found to have facets
a few μm wide that share a twin-domain boundary in thearmchair edge direction. This “armchair facet” wascharacterized by μm-scale VB mapping. The normal
direction of the “armchair facet” differed from that of
the terrace region by about 20°. The π-band splitting due
to interlayer interaction was the same in the “armchair
facet” and the terrace region, indicating that the interlayer
distance between the two regions was identical. By
transforming the photoelectron distribution of theselected momentum direction in reciprocal space to real
space, a momentum-selective microscopic image can beobtained. By detecting photoelectrons of the “armchair
facet” at the M symmetry point, a microscopic image inwhich the “armchair facet” is selectively enhanced was
successfully obtained [4].
Furthermore, the kz dispersion of graphite from thefew mm region was measured using photoelectron
momentum microscope (Fig. 1). The π band dispersion
over the entire Brillouin zone was investigated. Notethat graphite crystals with an ABAB…-type stacking
structure are six-fold symmetric around the z axis,
whereas a surface with one type of termination isthree-fold symmetric. The microscope function of the
PMM has a detection area sufficiently small to select
only one type of graphite termination structure on thecleavage plane. We found that the π band was nolonger degenerate in the ALH plane and its symmetry
was reduced from C6v to C3v. This phenomenon is
attributed to the coupling of the single-domain threefold graphite surface π-band with the six-fold bulk kz
dispersion, which has been neglected up to now. Thissymmetry breaking was used to image the monatomic
steps on the graphite surface [5].
[1] F. Matsui S. Makita, H. Matsuda, T. Yano, E.
Nakamura, K. Tanaka, S. Suga, and S. Kera, Jpn. J.
Appl. Phys. 59 (2020) 067001.
[2] S. Makita, H. Matsuda, Y. Okano, T. Yano, E.
Nakamura, Y. Hasegawa, S. Kera, S. Suga, and F.
Matsui, e-J. Surf. Sci. Nanotech. 19 (2021) 42.
[3] F. Matsui, S. Makita, H. Matsuda, E. Nakamura, Y.
Okano, T. Yano, S. Kera, and S. Suga, J. Phys. Soc.
Jpn. 90 (2021) 124710.
[4] F. Matui, Y. Okano, H. Matsuda, T. Yano, E.
Nakamura, S. Kera, and S. Suga, submitted (2022).
"Domain-resolved Photoelectron Microscopy and μmscale Momentum-resolved Photoelectron Spectroscopy of Graphite Armchair Edge Facet".
[5] F. Matui and S. Suga, submitted (2022) "Couplingof graphite surface π band with kz dispersion"

14014 Ⅲ04-

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Ⅲ -4. Surface, Interface and Thin Films

BL6U

Development of the Fabrication System for the μm-scale Ultra-thin Filmat BL6U
T. Nakamura1,2, F. Matsui3 and S. Kimura1,2,4

Graduate School of Frontier Biosciences, Osaka University, Suita 565-0871, Japan
Department of Physics, Graduate School of Science, Osaka University, Toyonaka 560-0043, Japan
3
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
4
Institute for Molecular Science, Okazaki 444-8585, Japan1

2

Photoelectron spectroscopy (PES) is a powerful
technique to investigate the electronic structures ofmaterials. Recently developed at UVSOR-III BL6U,
synchrotron-based photoelectron momentum microscopy(PMM) is one of the state-of-the-art PES systems [1]. On
the other hand, research on unique electronic states in the
microscopic region, such as edge states in topologicalmaterials and domains in inhomogeneous samples, hasbeen intensively explored [2-4]. The combination of
PMM and small-sized samples with the unique electronic
state leads to fertile physics. In this work, we havedeveloped a new thin-film deposition system in the
preparation chamber at the BL6U end station.
The basic concept of this system is the selective
deposition of the materials passes through the spatial
mask filter from the evaporator. Figure 1(a) shows thephoto of the flagship-type sample holder with two M2
holes to attach the additional filter component. Spotwelded Ta foils are used to fix a substrate. Figure 1(b)shows the mask filter. The main material is a flat Ta foil
(10 × 10 mm2) with a φ2 mm hole at the center. A
honeycomb-type TEM grid (The hole and bar sizes on
the TEM grid are 290 μm and 59 μm, respectively) wasused to make a pattern in the current system. A
commercially available square clip (4 × 4 mm2) is used
as a handle to fix the mask on the sample. The opposite
side of the clip is an M2 screw. Figure 1(c) shows thephoto of the sample holder with the mask filter on aheating stage in the preparation chamber of the BL6U
end station. The distance between the holder and mask
filter is about 1.5 mm. When cleaning the substrate byannealing and Ar sputtering, the mask filter is removed
and set to other sample holders on the sample bank.
We used the InSb(111)B substrate as a test sample.
The substrate was cleaned by the cycle of Ar-ion
sputtering (acceleration energy of 1 kV) and annealing
up to 600 K. After checking the sharp (3 × 3) diffraction
pattern, the 1-nm Sb layer was evaporated on the
InSn(111)B substrate with the mask filter at room
temperature.
Figure 2 shows a spatial-resolved In 4d core level
intensity map. One pixel indicates the sum of thephotoelectron intensity measured by the microscopymode of PMM. The domain scale of the bright area isalmost consistent with the size of the bar of the TEM
grid.
As the next step, we quantitively evaluate the spatial

resolution of selective deposition with mask filters andobserve the band structure from a single micro-scaledomain.

Fig. 1. Photos of the spatially selective deposition
system. (a) sample holder. (b) mask filter. (c) sample
holder with mask filter on a heating stage in the
preparation chamber of BL6U.

Ⅲ- 4

Fig. 2. Real-space image of the In 4d photoelectron
intensity plot. The incident photon energy is 80 eV.

[1] F. Matsui et al., Jpn. J.Appl. Phys. 59 (2020) 067001.
[2] K. Nakayama et al., Nano Lett. 19 (2019) 3737.
[3] R. Noguchi et al., Nature 566 (2019) 518.
[4] H. Iwasawa, Electron. Struct. 2 (2020) 043001.

14115 Ⅲ04-

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Ⅲ -4. Surface,
Interface and Thin Films

BL7U

High-resolution Angle-resolved Photoemission Study on
MnBi2Se4/Bi2Se3/MnBi2Se4 Sandwich Structure
2

Ⅲ- 4

R. Fukushima1, S. Ichinokura1, K. Tanaka2 and T. Hirahara1

Department of Physics, Tokyo Institute of Technology, Tokyo 152-8551, JapanUVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
1

Topological insulators (TI) are extensively studied
recently due to its peculiar properties [1]. The Diraccone surface states of TI are protected by time-reversal
symmetry (TRS) and backscattering among thesesurface states is prohibited. But when TRS is broken byapplication of a magnetic field or incorporating
magnetic materials, a gap opening in the Dirac cone is
expected and an intriguing phase called the quantum
anomalous Hall state can be realized [2]. This phase is
expected to show even more exotic phenomena such as
the topological magnetoelectic effect. To realize suchstate, two types of sample fabrication techniques havebeen employed up to now: (1) magnetic doping while
growing the single crystal or thin film of TI [3], and (2)magnetic impurity deposition on the surface of TI [4].
While method (1) was successful and showed evidenceof the TRS violation, no one has succeeded using
method (2), which should be a more direct way to
examine the interaction between the topological surface
states and magnetism. We have previously foundanother novel technique to induce magnetism into TI,
namely the magnetic extension effect [5]. By depositing
Mn and Se on Bi2Se3, we found that Mn and Se areincorporated in the topmost Bi2Se3 layer and a novel
heterostructure MnBi2Se4/Bi2Se3 is formed [5]. This
heterostructure with an ordered magnetic Mn single
layer showed a clear Dirac cone gap of 85 meV. Frommagnetic measurements utilizing high-resolution X-ray
magnetic circular dichroism (XMCD) at the Mn L
adsorption edge, it was revealed that the Curie
temperature Tc of the system is 15-20K. However, when
we fabricated a sandwich structure of MnBi2Se4/n
quintuple layer (QL) Bi2Se3/MnBi2Se4, which includes
two magnetic Mn layers, we found that the Tc wasenhanced to 20-25 K for n = 1-7. Thus it is important tomeasure the electronic structure of the sandwich
structure and investigate the origin of the enhancementof Tc.
Therefore in this study, we have measured the band
dispersion of MnBi2Se4/7 QL Bi2Se3/MnBi2Se4 sandwich
structure by angle-resolved photoemission spectroscopy(ARPES). The band dispersion measured at 10 K isshown in Fig. 1 system. It shows a band structure similar
to the heterostructure with a linear dispersion [5] and aquantitative analysis of the energy dispersion curve(EDC) at the Γ point revealed that the gap size was 100
meV. This result showed that there is practically little
difference between the hetero and sandwich structures.
Further magnetic characterization with XMCD including
measurements for nonmagnetic elements (Se or Bi)

have given new insights into the magnetic interaction of
the two Mn magnetic layers for the sandwich structure.
Namely it was revealed that the bulk carriers of the
Bi2Se3 near the Fermi level mediate the magnetic
interaction between the two Mn layers [6].

Fig. 1. Band dispersion image of the MnBi2Se4/7 QL
Bi2Se3/MnBi2Se4 sandwich structure measured at 10 K.

[1] M. Hasan and C. Kane, Reviews of Modern Physics
82 (2010) 3045.
[2] X.-L. Qi and S.-C. Zhang, Reviews of Modern
Physics 83 (2011) 1057.
[3] For example, C. Z. Chang et al., Science 340 (2013)
167.
[4] For example, M. Ye et al., Physical Review B 85
(2012) 205317.
[5] T. Hirahara et al., Nano Letters 17 (2017) 3493.
[6] R. Fukushima et al., to be published.

14216 Ⅲ04-

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Ⅲ -4. Surface, Interface and Thin Films

BL7U

Observation of Electronic Structure of YbCu2/Cu(111) Surface Alloy
H. Sugihara1, T. Nakamura2,1, Y. Chen1, K. Tanaka3 and S. Kimura2,1,4

Department of Physics, Graduate School of Science, Osaka University, Toyonaka 560-0043, Japan
2
Graduate School of Frontier Biosciences, Osaka University, Suita, 565-0871, Japan
3
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
4
Department of Materials Molecular Science, Institute for Molecular Science, Okazaki 444-8585, Japan
1

The Kondo coupling between localized f-electronsand carriers leads to exotic physical phenomena such as
the formation of the heavy-fermion (HF), theemergence of a magnetic quantum critical point, andunconventional superconductivity [1]. Among them, theHF system, in which massive effective carriers appear
due to the Kondo effect, has fascinated many
researchers [2,3]. On the other hand, the combination of
HF system and low-dimensionality strongly modulate
the hybridization strength because an order parameterof these systems is much sensitive to dimensionality. Ina typical bulk HF compound, CeIn3, for instance, thesuppression of the antiferromagnetism and the increaseof the carrier’s effective mass appear due to the
reduction of the dimensionality [4]. In addition, a HF
quasicrystal, which has higher dimensionality, has an
unconventional quantum criticality [5]. To clarify the
relation of the dimensionality to the HF character, weinvestigate electronic structure of low-dimensional HF
materials. Here, we have studied the surface electronic
structure of a HF surface alloy, YbCu2/Cu(111), which
is a new candidate for the two-dimensional HF system,measured by angle-resolved photoelectron spectroscopy(ARPES).
The clean Cu (111) substrate was prepared by thecycle of Ar+ sputtering and annealing up to 800 K. Afterchecking a sharp and low-background streak electron
diffraction pattern, Yb-metal was evaporated by ahomemade Knudsen cell, resulting in the observation of
fractional order originated from the YbCu2 layer.
ARPES measurement was carried out at UVSOR BL7U(hν = 21 eV) at temperature of 6 K.
Figure 1 shows the ARPES intensity plot of
� on a surface
YbCu2/Cu(111) surface along Γ� - K
Brillouin zone of Cu(111). To see the band dispersion
above the Fermi level, the ARPES spectra were divided
by the Fermi-Dirac distribution function convolved
with the instrumental resolution. The flat bands with thebinding energy of around 0.2 eV are attributed to theYb2+ 4f7/2 final state after the photoexcitation process.
Several hole bands centered on the Γ� point wereobserved. The hybridizations between the hole bands
and the Yb 4f state appears as the modulation of the
shapes and intensities. In addition to the hybridization,
as shown in Fig. 2, a steep peak, which seems to be a
Kondo resonance peak usually observed in HF
materials [6], appears near the Fermi level. These results
suggest the HF formation in YbCu2/Cu(111).
Further analysis to understand the hybridization
between the Yb 4f orbital and conductive hole bands

and the relation to the dimensionality are in progress.

Fig. 1. ARPES band dispersion of YbCu2/Cu(111)
� taken at hν = 21 eV (T = 6 K). The
surface along Γ�-Kphotoelectron intensities were normalized by FermiDirac distribution function convoluted with the
instrumental resolution.

Fig. 2. Angle-integrated photoelectron spectra of
YbCu2/Cu(111). The allow indicates the Kondo
resonance peak.
[1] C. Pfleiderer, Rev. Mod. Phys. 81 (2009) 1551.
[2] A. C. Hewson, The Kondo Problem to Heavy
Fermions (Cambridge Univ. Press, Cambridge, 1993).
[3] P. Coleman et al, J. Phys.: Condens. Matter 13 (2001)
R723.
[4] H. Shishido et al., Science 327 (2010) 980.
[5] K. Deguchi et al., Nat. Mater. 11 (2012) 1013.
[6] S. Chatterjee et al., Nat. Commun. 8 (2017) 852.

14317 Ⅲ04-

Ⅲ- 4

BL7BInterface and Thin Films
Ⅲ -4. Surface,

BL7B

Electrochemical Attenuated Total Reflectance Ultraviolet (EC-ATR-UV)
Spectroscopy Applied for Organic Semiconductor / Ionic Liquids Interface
I. Tanabe, Y. Hanamori and K. Fukui

Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University,
Toyonaka 560-8531, Japan

Ⅲ- 4

Electric double-layer organic field-effect transistors(EDL-OFETs) have attracted much attention because of
their significantly low operation voltage (<1 V)compared to conventional SiO2-gated OFETs (>10 V).
In EDL-OFETs, a high electric field is generated in the
EDL that accumulates in the interfacial region between
the organic semiconductor and electrolyte, resulting ina low operation voltage. Therefore, the organic
semiconductor/electrolyte interface is especially important.
Recently, we developed a new spectroscopic system,
namely electrochemical- attenuated total reflectance(EC-ATR) ultraviolet-visible spectroscopy, which canaccess the interfacial area [1,2].
In this study, ionic liquid gated organic field-effecttransistors (IL-gated OFETs) were fabricated on the
ATR prism (Fig. 1). Two-layer single crystalline film of
C9-DNBDT-NW was used as an organic semiconductor,
and two kinds of ionic liquids ([EMIM][FSA] and[TMPA][TFSA]) were cast on the film. Au films were
evaporated to a thickness as the source and drainelectrodes (working electrodes) on both sides of the
ATR prism, and a Pt coil and a Pt wire were placed in
the ionic liquids as pseudo counter and reference (gate)electrodes, respectively. In our previous study [2], in
response to the applied gate voltage, the spectral peaksof the organic semiconductor shifted and bleached. Thiswas correlated with the drain current.
The fabricated IL-gated OFETs on the ATR prism
was put on the sample chamber in BL7B at UVSOR.
The light from UVSOR had one important advantage;
polarization direction control. That is to say, by changing
the placing direction of the ATR prism to the incident
light, the polarized direction to the sample can becontrolled. While our previous study used a halogen
lamp as the light source, which was unpolarized, thesynchrotron radiation is innately polarized. in the UV
region, especially in the deep-UV (<300 nm) region, thepreparation of a polarizer is difficult, and thus, thepolarized light generated from the synchrotron is highly
useful.
Figure 2 shows the ATR spectra of C9-DNBDT-NW
on the sapphire prism measured in BL7B at UVSOR.
While the s-polarized incident light gave distinct peaksin the 200-500 nm range (Fig. 2 (a)), p-polarized incident
light did not (Fig. 2 (b)). This is because the C9-DNBDTNW film on the ATR prism was well packed, and shows
strong polarized dependence.
These peaks could be assigned by quantum chemical
calculations, and they verified depending on the applied
voltage [2]. In addition, EC-ATR-UV spectroscopy

could measure the absorbance due to the ionic liquids
near the surface of the C9-DNBDT-NW film because of
the short penetration depth (< 50 nm) and the strong
ionic liquids’ absorbance of the light in the UV region,
which was a unique point of the new technique.
Therefore, we are trying spectral measurements of bothorganic films and ionic liquids during device operations
using the polarized light from BL7B. It will reveal
orientations of interfacial ionic liquids and their behaviors
under electrochemical environment. Additionally, theinteractions between the organic semiconductor film
and ionic liquids will be investigated, leading to themechanism research and improvement of the highperformance EDL-OFETs.

Fig. 1. Schematics of EDL-OFET fabricated on ATR
prism.

Fig. 2. Polarization dependence of ATR spectra of C9DNBDT-NW on a sapphire prism.

[1] I. Tanabe, A. Suyama, T. Sato and K. Fukui, Anal.
Chem. 91 (2019) 3436.
[2] I. Tanabe, I. Imoto, D. Okaue, M. Imai, S. Kumagai,
T. Makita, M. Mitani, T. Okamoto, J. Takeya and K.
Fukui, Commun. Chem. 4 (2021) 88.

14418 Ⅲ04-

UVSOR User 6

UVSOR User 7

Ⅲ-5

Life, Earth andPlanetary Sciences

BL4UⅢ -5. Life, Earth and Planetary Sciences

BL4U

Hayabusa2 Returned Samples: Unique and Pristine Record of Solar System
Materials from Asteroid Ryugu
M. Ito1, N. Tomioka1, M. Uesugi2, A. Yamaguchi3,4, N. Imae3,4, N. Shirai5, T. Ohigashi4,6,
M. Kimura3, M-C, Liu7, R.C. Greenwood8, K. Uesugi2, A. Nakato9, K. Yogata9, H. Yuzawa6,
Y. Kodama15, A. Tsuchiyama10, M. Yasutake2, R. Findlay8, I.A. Franchi8, J.A. Malley8,
K.A. McCain7, N. Matsuda7, K.D. McKeegan7, K. Hirahara11, A. Takeuchi2, S. Sekimoto12,
I. Sakurai13, I. Okada13, Y. Karouji14, T. Yada9, M. Abe9, T. Usui9, S. Watanabe13
and Y. Tsuda4,91

JAMSTEC Kochi, 2JASRI/SPring-8, 3NIPR, 4SOKENDAI, 5Tokyo Met. Univ., 6UVSOR/IMS, 7UCLA, 8Open Univ.,
9
JAXA/ISAS, 10Ritsumeikan Univ., 11Osaka Univ., 12Kyoto Univ., 13Nagoya Univ., 14JAXA/JSEC, 15Toyo Corp.

The Hayabusa2 spacecraft successfully returned
surface materials from the C-type asteroid Ryugu to
Earth on December 6th, 2020. The sample capsulecontained a large number of small grains, collected fromtouchdown (TD) sites 1 and 2 on Ryugu, with a total
mass of ~5.4 g [1]. After initial characterization of thegrains by JAXA curation [1,2], eight Ryugu particles(~60 mg in total), four from Chamber A and four from
Chamber C, were allocated to the Phase2 curation
Kochi team (Ph2K). The principal goals of the research
are to elucidate the nature, origin, and evolutionary
history of asteroid Ryugu, and to document thesimilarities to and/or differences from other known
extraterrestrial samples, such as chondritic meteorites,
interplanetary dust particles and returned cometary
samples collected by the NASA Stardust mission.
The coordinated micro-analysis work involved theuse of a wide range of multi-beam instruments to acquiredetailed micro-textural and chemical information about
the samples at a sub-micrometer scale using a
combination of FIB, STXM-NEXAFS, NanoSIMS andTEM [4,5]. In parallel, we conducted bulk systematic
analysis of the samples using SEM-EDS, EPMA, XRD,
large geometry type SIMS, high precision O isotopic
analysis by laser fluorination and INAA [4-8].
Using a combination of STXM-NEXAFS –NanoSIMS – TEM techniques, we have been able toestablish the spatial distribution of organics with an
aliphatic-rich carbon structure that are associated withphyllosilicates at sub-micrometer scale in the C006825 FIB section (Fig. 1).
C-NEXAFS spectra in the C0068-25 section show avariety of functional groups of aromatic (or C=C),
C=O, C-H or aliphatic, and C(=O)O, without 1s-σ*
exciton of graphene structures (Fig. 1(A)). Figure 1(B)shows the spatial distribution of carbon in the section.
In Fig. 1(C), three representative areas of aromatic (orC=C)-rich organics can be seen in red, aliphatic-richcarbon is shown in green and matrix in blue. Areas
with an intense aliphatic-rich carbon structure (green
area in Fig. 1(C)) are present locally in coarse-grained
phyllosilicates in the section (Fig. 1(D)), as well as
areas with a poorly aromatic (C=C) carbon structure.

The distribution of organics with an aliphatic carbon
structure may vary significantly depending on theexistence of coarse-grained phyllosilicates. The CNEXAFS revealed that the organics in the Ryugu
particles are chemically distinct from the previously
studied IOM of the Murchison CM chondrite [8]andshow greater similarity to IDPs [9] and cometary
particles obtained by the Stardust mission [10].
A question that arises is whether the unique natureof the aliphatic carbon-rich organics associated withcoarse-grained phyllosilicates observed in this study isa unique feature, only found in the Ryugu asteroid.
This question requires additional work. Further study
is needed to fully define the nature of the organics andtheir relationship with the surrounding hydrous
mineral phases.

Ⅲ- 5[1] Yada T. et al., Nature Astron (2021)
doi.org/10.1038/s41550-021-01550-6.
[2] Pilorget, C. et al., Nature Astron (2021)
doi.org/10.1038/s41550-021-01549-z.
[3] Uesugi M. et al., Rev. Sci. Instrum. 91 (2020) 035107.
[4] Ito M. et al., Nature Astron, in revision (2022).
[5] Tomioka N. et al., 53rd LPSC (2022).
[6] Yamaguchi A. et al., 53rd LPSC (2022).
[7] Greenwood R.C. et al., 53rd LPSC (2022).
[8] Cody, G.D. et al., Earth Planet. Sci. Lett. 272 (2006)
446.
[9] Keller, L.P. et al., Geochim. Cosmochim. Acta 68(2004) 2577.
[10] Sandford S.A. et al., Science 314 (2006) 1720.

149 1 Ⅲ05-

Ⅲ -5. Life,BL1U
Earth and Planetary Sciences

BL1U

Study of Pygmy Dipole Resonance using Linearly Polarized Photon BeamT. Shizuma1, M. Omer2, T. Hayakawa1, K. Ali3, H. Zen3, H. Ohgaki3, S. Miyamoto4,
K. Sugita5 and Y. Taira5

National Institutes for Quantum Science and Technology, Tokai 319-1106, Japan
2
Japan Atomic Energy Agency, Tokai 319-1195, Japan
3
Institute of Advanced Energy, Kyoto University, Uji 611-0011, Japan
4
Laboratory of Advanced Science and Technology for Industry, University of Hyogo, Kamigori 678-1205, Japan
5
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan1

the intensity asymmetry of resonantly scattered γ-rays
with respect to the polarization plane of the incident
photon beam.

Fig. 1. Photo of the experimental setup used for NRF
measurements at BL1U.
410Counts / 1 keV

Ⅲ- 5

The emergence of low energy dipole strength socalled Pygmy Dipole Resonance (PDR) has motivatedmany experimental and theoretical efforts [1]. The PDR
has been observed as a concentration of electromagnetic
strength near the low-energy tail of the Giant Dipole
Resonance (GDR). It provides useful information on
fundamental properties such as the neutron-skinthickness of medium to heavy nuclei, the nuclear
symmetry energy, and the properties of neutron stars.
The stable lead isotopes, including 206Pb, are suitable forthese studies since they exhibit an appreciable amountof low-energy dipole strength.
In a previous nuclear resonance fluorescence (NRF)
measurement for 206Pb using unpolarized bremsstrahlung[2], extra strengths were observed at the energy region
ranging from 5 to 8 MeV which could be related to the
PDR. The photo-absorption cross sections in 208Pb in
average amount to about 60% of that in 206Pb. Thisbehavior differs from that found in the series of xenon
isotopes, in which the summed dipole strength in theenergy region from 6 to 9 MeV increases with theneutron numbers [3]. Possible reasons are that thestrength in the quasi-continuum may not be neglected in
208
Pb either or that there are structural differences thatinterfere the effect of the neutron excess [3].
To study the PDR nature in 206Pb we measured NRF
γ rays using linearly polarized photon beam. The laser
Compton scattering (LCS) γ rays with a maximum
energy of 7.54 MeV were generated by collision of 746MeV electrons with linearly polarized laser photons
with a wavelength of 800 nm at a collision angle of 82
degrees. A lead collimator with a 18-cm thickness and
3-mm aperture was used to form a quasi-monochromatic
LCS photon beam. The photon flux was measured
during the NRF measurement by a large volume LaBr3
scintillation detector. The target consisted of a metallic
cylinder (8 mm in diameter) of enriched 206Pb. Fourhigh-purity germanium (HPGe) detectors were used tomeasure scattered photons from the target. Two of thesedetectors were placed in the horizontal plane at ascattering angle of 90 degrees and the others wereplaced in the vertical plane. The experimental setup is
shown in Fig. 1. A part of the photon scattering spectra
observed at a polar angle of 90 degree relative to thepolarization plane of the incident photon beam isrepresented in Fig. 2. The measured spectra are used todetermine the parities of the resonant states by extracting

2

10

0

10

0

4000
Energy (keV)

8000

Fig. 2. Typical γ-ray spectrum observed at a polar
angle of 90 degrees relative to the polarization planeof the incident photon beam.

[1] D. Savran et al., Prog. Part. Nucl. Phys. 70 (2013)
210.
[2] T. Shizuma et al., Phys. Rev. C 98 (2018) 064317.
[3] R. Massarczyk et al., Phys. Rev. Lett. 112 (2014)072501.

150 2 Ⅲ05-

BL3U

Ⅲ -5. Life, Earth and Planetary Sciences

BL3U

X-ray Absorption Spectra of Lipid Bilayer Membranes in Aqueous Solutions
R. Tero1, Yu Kinjo1 and M. Nagasaka2

Toyohashi University of Technology, Toyohashi 441-8580, Japan
2
Institute for Molecular Science, Okazaki 444-8585, Japan1

The lipid bilayer is a self-assembled structure ofamphiphilic lipid molecules and is the fundamental
structure of biomembranes such as cell membranes.
Internal structures of lipid bilayers, such as twodimensional domains and hydrophobic thickness, andphysical properties affect the transportation of materials,
information, and energy through the biomembranes. All
these physiological reactions proceed in the presence ofions. Ions in the aqueous solution significantly influence
to these structures and properties of lipid bilayers.
Phosphatidylcholine (PC) is the most abundant lipid ofeukaryotic cell membranes. Cations bind to thephosphate and carbonyl groups of PC. However, affinityof cations to PC and effects of cations to molecularorientation are still controversy especially in the fieldsof theoretical simulations [1]. We aim to determine thebinding affinity of cations to lipids in aqueous solutions
experimentally, by means of X-ray absorption
spectroscopy (XAS) [2,3].
Supported lipid bilayers (SLBs) of dioleoyl-PC(DOPC) were formed on the Si3N4 membranes of the
XAS flow cell [2] by the vesicle fusion method. We
prepared DOPC-SLBs with few residual vesicles asshown in Fig. 1. Fluorescence recovery after
photobleaching observation showed that fluid andcontinuous SLB covered the whole Si3N4 membranesurface. O-K edge XAS spectra of the Si3N4 membrane
before and after formation of SLB were obtained in abuffer solution (NaCl 100 mM, HEPES 25 mM/ pH 7.4
NaOH) which thickness was controlled to be less than
100 nm. The XAS spectrum of the Si3N4 membranewithout SLB was subtracted from that with SLB.
The O-K-edge spectrum of DOPC appeared at 531- 533 eV (Fig. 2). It is attributed to three components
due to the phosphate and carbonyl groups on the PC
headgroup: 1s→π* transitions of P=O, P-O-Na, and
C=O at 531.5 eV, 532.3 eV, 532.0 eV, respectively [3].
We measured XAS spectra at different incident angle toobtain the orientation of these groups in the lipid bilayer[4]. The relative intensity of the three components
varied with the incident angle (Fig. 2). The result
indicates that XAS in the aqueous sotion is capable toobtain information about the molecular orientation oflipids in bilayer membranes.
In conclusion, we obtained O-K edge XAS spectraof SLBs in an aqueous solution at various incident
angles. We will investigate the effects of the cation
concentration and species on the XAS components andtheir relative intensities.

Fig. 1. Fluorescence image of DOPC-SLB on the the
Si3N4 membranes of the XAS flow cell.

a

b

c

Ⅲ- 5

Fig. 2. O K-edge XAS spectra of DOPC-SLB obtained
at various incident angle: (a) 0°, (b) 35°, and (c) 48°.
Black dotted curves represent raw data. Dashed curves
and red solid curves show deconvoluted components
and their summation, respectively.
[1] T. B. Woolf, Biophys. J. 104 (2013) 746; A. Catte,
Phys. Chem. Chem. Phys. 18 (2016) 32560.
[2] M. Nagasaka, H. Yuzawa, T. Horigome, and N.
Kosugi, J. Electron Spectros. Relat. Phenomena 224(2018) 93.
[3] R. Tero, W.-Z. Goh and M. Nagasaka, UVSOR
Activity Report 2020 48 (2021) 129.
[4] H. Kondoh, F. Matsui, Y. Ehara, T. Yokoyama and
T. Ohta, Langmuir 17 (2001) 8178.

151 3 Ⅲ05-

Ⅲ -5. Life,BL4U
Earth and Planetary Sciences

BL4U

Evaluation of Exposure-Effects on Biomolecules for the Molecular Mappingof Biological Specimens Using STXM
A. Ito1, K. Shinohara2, A. Matsuura3, S. Toné4, M. Torigata1, K. Tohya5, H. Yuzawa6
and T. Ohigashi6,7

1School of Engineering, Tokai University, Hiratsuka 259-1292, Japan
Graduate School of Health Sciences, Fujita Health University, Toyoake 470-1192, Japan
3
Research Integrity Office, Fujita Health University, Toyoake 470-1192, Japan
4
School of Science and Engineering, Tokyo Denki University, Hatoyama 350-0394, Japan
5
Kansai University of Health Sciences, Kumatoricho 590-0482, Japan
6
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
7
School of Physical Sciences, The Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan2

though the repeated measurement and confirmation of
the results remained.
2.5

Absorption

(a)

2
1.5
1
0.5
0

(b)

283

285

287 289 291 293
Photon energy (eV)

295

397

399

401 403 405 407
Photon energy (eV)

409

530

532

534 536 538 540
Photon energy (eV)542

Absorption

1.5
1
0.5
0

(c)

1.5
Absorption

Ⅲ- 5

It is well recognized that spectromicroscopy using ascanning transmission X-ray microscope (STXM) inthe soft X-ray region is a powerful tool for themolecular mapping of biological specimens. We havebeen working on a quantitative mapping of nucleic
acids (DNA and RNA) and proteins (histone andbovine serum albumin abbreviated as BSA) in
chromosomes, cultured mammalian cells, and isolated
apoptotic nuclei using combined NEXAFS spectra at
the C, N and O-K absorption edges [1-3].
In the quantitative analysis, precise absorption
spectra of constituent molecules are definitely required.
However exposure of X-rays for the observation itself
could induce molecular changes resulting in the spectralchanges of them. Actually, we have calculated theexposure and absorption doses for biological specimens
in a hydrated condition to achieve a defined spatial
resolution based on the method by Sayre et al. [4], andestimated the number of DNA strand breaks generated[5]. For example to obtain 100 nm spatial resolution, theabsorption dose in the order of 104 Gy is required, which
induces about 105 DNA double strand breaks per cell.
In the present study, we evaluated the exposure-effects
on the spectra of major biological molecules such as
DNA, RNA, histone and BSA as a trial.
We prepared dry thin films of DNA, RNA, histone,
and BSA on SiN membrane. Each one micrometersquare area in the specimens was scanned with 10 x 10
pixels at the energy of C, N and O-K absorption edge
regions in this order with a dwell time of 6, 12 and 20
msec in addition to 2 msec for DNA. For each dwell
time the scanned area was shifted to the different area.
Figure 1 shows NEXAFS of DNA at the C, N and
O-K absorption edges with four kinds of dwell times.
A slight but significant change was observed in the
profiles of the spectra, though it was not clear whether
or not that was depending on the level of exposures.
In the case of RNA and histone, similar tendency
was observed. However for BSA, a clear change in the
profiles was observed in a dwell time dependent
manner.
At this stage of the results, we decided that spectra of
the molecules observed at the same exposure condition
should be chosen as the reference data for analysis,

1
0.5
0

Fig. 1. NEXAFS of DNA at the C-K (a), N-K (b), andO-K (c) edges. Dwell time: 2 (black), 6 (red), 12 (blue),and 20 (green) msec.

[1] K. Shinohara et al., Ultramicrosc. 194 (2018) 1.
[2] K. Shinohara et al., J. X-Ray Sci. Technol. 26 (2018)877.
[3] K. Shinohara et al., Cells 8 (2019) 8.
[4] D. Sayre et al., Ultramicrosc. 2 (1977) 337.
[5] K. Shinohara and A. Ito, J. Microsc. 161 (1991) 463.

152 4 Ⅲ05-

BL4U

Ⅲ -5. Life, Earth and Planetary Sciences

BL4U

Physicochemically Characterization of Dust/Salt Mixtures Originatingfrom the Source of East Asian Dust Storms
1

J. Li1, W. Liu1, L. Li2, T. Ohigashi3, M. Hallquist2, S. Wang1 and X. Kong2

Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, Northwest University,
Xi'an 710127, China
2
Department of Chemistry and Molecular Biology, University of Gothenburg, SE-412 96 Gothenburg, Sweden
3
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan

Mineral dust aerosols are a primary component in theatmosphere, accounting for almost half of troposphericaerosol masses, and they can deteriorate human living
conditions, endanger human health, and affectecosystems. In the context of global climate change, thetrend of warming and drying that is intensifying
desertification in northern China is clear. The dominantregional geophysical feature, the neighboring Third Pole,that is the elevated region represented by the Himalayas
and the Tibetan Plateau, impacts the entire planet’s
climate directly and via global teleconnections [1]. In
this study, dust, salts and mixed samples were collectedfrom important source regions of East Asian Dust
Storms, including the Badain Jaran Desert, the Tengger
Desert and the Ulan Buh Desert in northwestern China.
Scanning transmission X-ray microscopy (STXM)
measurements were performed at the BL4U UVSORIII beamline. For STXM measurements sample
particles were deposited on filmed TEM grids, anddata was analyzed with the aXis2000 program.
Example optical images are presented in Fig. 1, where
Fig. 1(a) is an image captured at 348 eV photon energy,
corresponding to calcium absorption. Potassiumcontaining particles in the same sample are highlighted
in Fig. 1(b) (297 eV) as the dark more cubic particles.
Individual particles were chemically mapped using
the STXM technique. Particle images are shown in Fig.
2 and a zoomed-in view in Fig. 2(a). Figure 2(a) shows
the two typically observed particle morphologies,
needle-like and more cubic or polygonal. We observedistinct chemical characteristics of the twomorphologies, as illustrated in Figs. 2(b)–2(d), which
include the carbon K-edge and potassium L-edge
spectra, the calcium L-edge spectra and the oxygen Kedge spectra.
The carbon K-edge includes the presence of acarbonate peak (at 290.2 eV) for needle particles that is
minimally present for the polygonal particles [2]. Given
the region around 284–290 eV is flat, these particles
cannot include significant black or organic carbon
components. At the potassium L-edge, a doublet at297.2 and 299.8 eV indicates the presence of potassiumin the polygonal particle [3]. In Fig. 2(c), the calcium Ledge shows the presence of calcium (at 348.8 and 352.1
eV) in the needle, suggesting the needle is likely CaCO3[2]. At the oxygen K-edge (Fig. 2(d)), one sharp peak isobserved at 533.6 eV in the needle, which likely
corresponds to the oxygen in the carbonate ions, whichfurther supports the supposition that the needle-likeparticles are dominated by CO3 and Ca. The broad

components in the oxygen K-edge spectra are associatedwith other oxygen species. These results show themixing state of the CaCO3 and K/O salts in sandsamples, and these two components most likely havedifferent solubilities, i.e., CaCO3 has low solubility inwater, but the K/O salts may be highly dissolvable. The
STXM results here provide unique information thatcannot be accessed by other conventional methods.

Fig. 1. STXM images shows the morphology ofdust/salt mixture particles. (a,b) Snapshots measured
at 348 eV and 297 eV.

Ⅲ- 5Fig. 2. STXM image and spectra of representative
particles. (a) Optical image, (b) spectra scanned at C
K-edge and K L-edge, (c) Ca L-edge spectra, (d) O Kedge spectra. Blue lines and red lines represent themean spectra for needle-like particles and polygonal
particles, respectively.
[1] Q. You et al., Earth-Sci. Rev. 217 (2021) 103625.
[2] K. Benzerara et al., Geobio. 2 (2004) 249.
[3] R. C. Moffet et al., Atmo. Chem. Phys. 13 (2013)
10445.

153 5 Ⅲ05-

Ⅲ -5. Life,BL5B
Earth and Planetary Sciences

BL5B

Development of Multilayer-coated Mirrors for the Next Generation of the
Inner Magnetospheric Imaging
K. Inoue1, A. Tomioka1, J. Yang 2, H. Lin2, K. Yoshioka1,2 and I. Yoshikawa1,2

Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo,
Tokyo 113-0033, Japan2
Department of Complexity Science and Engineering, Graduate School of Frontier Sciences, The University of Tokyo,
Chiba 277-8561, Japan1

Ⅲ- 5

Inner magnetospheric imaging at 30.4 nm, which is aresonantly scattered emission line by singly-ionizedhelium, contributed to our present understandings ofplasmasphere formation, emerges of fine structures andsolar wind interaction. RemFigote-sensing technique inthis spectral region has become known as a promising
tool in geophysics.
We have still strong motive in extension of the innermagnetospheric imaging since instrument developments
on Kaguya, Nozomi, International Space Station. A
multilayer coated mirror reflecting the EUV radiation at
the normal incidence has been providing solutions to
overcome the technical difficulties, i.e., existing optics
has less effective collection of EUV photons. Therefore,
multilayer coated mirrors have been employed for solar
physics and astrophysics as well. The multilayer coating
consisting of alternating layers of typically molybdenum
and silicon (Mo/Si) achieved the highest and stablereflectivity (approximately 20 %) at 30.4 nm, andtherefore it has been most often employed in the space
missions. The thickness of each layer should bedetermined by the trade-off as follows: it maximizes theconstructive interference of the incidence reflected ateach interface and it minimizes the total absorption to
enable more interfaces to contribute to the absolutereflectance increase.
Recently, we have shown the performance of the newmultilayer coated mirror, consisting of 40 pairs of Mg
and SiC. Its peak reflectivity achieved 30 % or higher.
However, we had to realize that the Mg/SiC multilayer
mirror has decisive disadvantage. The degradation of
the reflectivity occurred under the condition of hightemperature and/or high humidity. The interface between
two materials became unstable, the thickness of thelayer changes due to interfacial tension, and then thereflectance decreased dramatically (diffusion problem).
As a result, we were forced to use a conventional
multilayer mirror.
Space mission payloads have to survive hot and/or
humidity environments before the launch as well asvery cold condition in space. The development ofrobust instruments against environmental changes ismandatory for us.
More recently, we have designed a new multilayer
coating, (B4C/MgSi). We use the metal alloys of MgSi
instead of using bulk of Mg to solve diffusion problems.
Figure 1 shows the reflectivity of the coating for S- andP- polarizations. For both polarizations, the measured

reflectivities are relatively ~ 25 % lower than those of
the expectations by calculations (We have an ordinary
way using optical constants [1] to calculate thereflectivity). We will have some modification on the
manufacturing process (e.g., Mg/Si ratio) to increase up
to the expectations.
On the other hand, for non-polarization radiation (thatis our target in planetary science), we expect that we haveachieved higher reflectivity (average over S- and Ppolarizations, about 30 %) than that of a conventional
Mo/Si coating. The development will be progress nextyear.

Fig. 1. Reflectivity of the multilayer coating of
B4C/MgSi. We have measured the reflectivity for both
S and P polarizations. Predictions by the calculations arealso shown.

[1] Eric Gullikson. The Center for X-Ray Optics.
Retrieved March 27, 2022, fromhttps://henke.lbl.gov/optical_constants/

154 6 Ⅲ05-

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Ⅲ -5. Life, Earth and Planetary Sciences

BL5B

Performance Evaluation of an Optical Filter Aiming for Observation of
Atmosphere of Comets
Y. Sasaki1, Y. Suzuki2, K. Yoshioka1,2, M. Taguchi3, M. Kuwabara3, H. Akadama2, T. Kosugi1,
H. Lin1 and J. Yang1
1

Department of Complexity Science and Engineering, Graduate School of Frontier Sciences, The University of Tokyo,
Chiba 277-8561, Japan2
Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo,
Tokyo 113-0033, Japan3
Departmemt of Physics, Graduate School of Science, Rikkyo University, Tokyo 171-8501, Japan

Investigating the hydrogen isotope (D/H) ratio of
emitted gases from comets is important to understandthe water-related history of the solar system. Here, weare developing a Lyman-alpha line absorption cell thatcan distinguish the emission line of D and H, by utilizing
the resonance absorption of the hydrogen atoms. To
evaluate its performance, accurate calibration of the
wavelength for the monochromator is required. However,the BL5B facility is known to have a drift-like tendency.
Therefore, we examined the temporal shift of the
wavelength using the known absorption line of the
Krypton (Kr) .
We evaluated the wavelength shift by irradiating the
EUV light to the absorption cell filled with Kr gas (Fig.
1). The measurements were conducted three times. For
all measurements, the scanned wavelength was from122.6 nm to 124.6 nm, and the scan step was 0.01nm.
The slit width was 0.01 mm. The pin hole diameterwas 1 mm, and the grating and the mirror were set as“G3M5”. The gas pressure of the Kr gas was 1000 Pa.
The result is shown in Fig. 2. The absorption
wavelength by Kr is 123.58 nm in literature [1]. However,the figure shows two primary absorptions, 123.50 nm
and 123.80 nm. We have two hypotheses for this result.
The one is that the absorption near the wavelength of
123.50 nm might be the absorption by Kr, since its
wavelength is near that of Kr in literature [1]. Based on
this hypothesis, the other absorption, which is around123.80 nm, should be an effect of other substances. A
possible substance is water molecules. They absorb
light near the wavelength of 122.00nm, 123.85 nm, and124.10 nm. It is difficult to completely prevent watermolecules from entering the cell, so some watermolecules remaining in the cell might absorb the lightnear 123.80 nm. However, if this hypothesis is correct,
an absorption near 124.10 nm also should appear. As the
future work, we plan to dry the Kr cell completely bybaking enough and confirm whether the absorption
around 123.80 nm is derived from water molecules.
The other hypothesis is that both two absorption
lines are caused by water molecules. It means that the
wavelength adjustment by approximately +0.30 nm isneeded. Based on this hypothesis, we have to consider
the possibility that the absorption by Kr is too faint toobserve. The future work for this case is the same as
mentioned above, since if both absorptions are effectsof water molecules, both absorptions would disappear

by drying the cell. Moreover, we also should find out
appropriate Kr gas pressure.
As a supplementary experiment, we also evaluatedthe upper limit of absorption rate by hydrogen byfilling the cell with hydrogen gas. It can be derived by
calculating the ratio of the standard deviation to theaverage direct count, using the hydrogen-filled cell.
We call it “relative error”.
The measurement was conducted 10 sets. Eachmeasurement set has three trials. The scanned wavelength
was from 119.6 nm to 123.6 nm, and the scan step was
0.02 nm. The slit width was 0.01 mm. The pin holediameter was 1 mm, and the grating and the mirror wereset as “G3M5”. The hydrogen gas pressure was 200 Pa.
Electric energy applied to the filament in the cell waschanged from (1.05 W, 2002 K) to (2.60 W, 2740K).
As a result, the average “relative error” was 2.31 %.
This means that if the absorption for hydrogen Lymanalpha is less than 2.31%, we cannot find it out.
Therefore, we have to adjust the power for the filament
so that the absorption exceeds the ratio.

Ⅲ- 5Fig. 1. The setup of experimental instruments.

Fig. 2. The absorption spectrum of Kr. It shows
primary absorptions at 123.50 nm and 123.80 nm.
[1] National Institute of Standards and Technology,
NIST Atomic Spectra Database Lines Data, https://physics.nist.gov/PhysRefData/ASD/lines_form. html.
Accessed March 2, 2022.

155 7 Ⅲ05-

Ⅲ -5. Life,BL5B
Earth and Planetary Sciences

BL5B

Performance Evaluation of UV Absorption Filter Onboard SpacecraftY. Suzuki1, M. Kuwabara2, M. Taguchi2, K. Yoshioka1,3, T. Katsumata2, M.Tateyama2, K. Goda4,
A. Yamazaki4, K. Inoue4 and A. Tomioka4
1
Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo,
Tokyo 113-0033, Japan2
Department of Physics, College of Science, Rikkyo University, Tokyo 171-8501, Japan3
Department of Complexity Science and Engineering, Graduate School of Frontier Sciences, The University of Tokyo,
Chiba 277-8561, Japan
4
Department of Earth and Planetary Physics, Faculty of Science, The University of Tokyo, Tokyo 113-0033, JapanⅢ- 5

In the planetary science, deuterium-hydrogen (D/H)
isotope ratio of comets is emphasized to know theorigin of water on Earth. We develop an imager
onboard the Comet Interceptor spacecraft to observethis. However, small spectrometers have too low
wavelength resolution to distinguish emission lines of
H and D, whose wavelength are different only by 33
pm. To overcome this difficulty, we use gas filters
named Hydrogen Absorption Cell. This is a small glass
cell filled with hydrogen molecules, in whichfilaments are set. By applying voltage to this filament,
hydrogen molecules dissociate into atoms resulting inabsorption of Ly-α. It is noted that Ly-α of deuterium
is not absorbed. Therefore, we can evaluate D/H ratio
from the difference of the brightness of the observation
target when the voltage is applied (called “on”) and not
applied (called “off”) to the filament.
Our experiments aim to understand appropriatepressure of filled hydrogen for the future comet
exploration. We obtained transmittance spectra withseveral pressure conditions through the comparison of“on” and “off” data. Then, absorption width and depth
are evaluated using Gaussian fitting. Wavelength
scanning was performed using the G3M4 grating
system with the range of 121.5-122.5 nm, 0.02 nm steps
and summing 20 times. The higher hydrogen pressureis, the more difficultly the filament temperature rises,
since hydrogen molecules take away the heat of thefilament. Thus, experiments were conducted under
three conditions –temperature of the filament is fixed,
power applied to the filament is fixed, and applied
voltage is fixed.
The results are shown in Fig. 1. When power orvoltage are fixed, the temperature of the filamentdecreases and absorption gets shallower with higher
pressure. On the other hand, when filament’s temperature
is fixed to 1800 K, absorption gets deeper. However,power consumption also increases. Although it seems
that intermediate pressure (from 200 to 400 Pa) is thebest so far, we need to precisely discuss it in terms oflifetime of filaments and available power onboard thespacecraft.
When voltage is applied, filaments are expected toglow like light bulbs, which causes the contaminationof observation data. To verify this fact, we measured
the brightness with shutters closed. As we expected,
the filament gets brighter as its temperature rises.
Besides, at constant temperature, higher hydrogenpressure is found to suppress the brightness. Utilizing
this knowledge, we will soon estimate the expected
S/N ratio of the instrument mounted on the spacecraft.

Fig. 1. Dependence of absorption width and depth on the pressure of filled hydrogen in the cell.

156 8 Ⅲ05-

BL7B

Ⅲ -5. Life, Earth and Planetary Sciences

BL7B

The Effect of Space Weathering on The PAH Wavelength of Interstellar
Dust Organic Matter
1

J. Yang1, H. Lin1, K. Inoue2, A. Tomioka2, K. Yoshioka1, 2 and I. Yoshikawa1, 2

Department of Complexity Science and Engineering, Graduate School of Frontier Sciences, The University of Tokyo,
Chiba 277-8561, Japan2
Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo,
Tokyo 113-0033, Japan

In astronomy, extinction is the absorption andscattering of electromagnetic radiation by dust and gas
between the emitting astronomical object and theobserver. Interstellar extinction was first recorded in1930 by Robert Julius Trumpler. However, its effects
were already noticed by Friedrich Georg Wilhelm vonStruwe in 1847, and its influence on stellar colors wasobserved by many, but they did not link it to theprevalence of galactic dust.
Polycyclic aromatic hydrocarbons (PAH) are aprevalent component of space organics and are present
in interstellar dust. They play an important role in avariety of astronomical observations in the ultraviolet
and far-infrared ranges, covering a wide range of objects
and environments from meteorites and interplanetary
dust particles to the outer solar system [1].
A prominent feature in the measured extinction
curves of many objects in the Milky Way is a broad"bulge" at about 2175 Å, right into the ultraviolet
region of the electromagnetic spectrum. This feature
was first observed in the 1960s, but its origin remains
unclear. Several models have been proposed to explain
the bulge, including graphite particles containing a
mixture of PAH molecules. Studies of embedded
interplanetary dust particles (IDPs) have observed thisfeature and identified the presence of carriers oforganic carbon and amorphous silicates in the particles.
The PAH present on Earth have an absorption bandwith a wavelength of about 210 nm. And due to theweathering of the universe, PAH may increase thewavelength range of the UV absorption band in theuniverse.
Therefore, it is assumed that the reflection band of
PAH on Earth has a wavelength of about 210 nm, which
may correspond to the absorption band of 217.5 nm thatappears in the interstellar darkening curve (the curve
describing the absorption spectrum of interstellar dust).
This experiment was conducted to observe andanalyze the effect of space weathering on the lightabsorption properties of PAH. We prepared PAH
samples Fig. 1) synthesized in the laboratory forcomparison experiments with PAH samples exposedon the International Space Station (ISS) (exposed
samples) and similar samples synthesized and stored
in the laboratory (unexposed samples), both exposed
and unexposed samples were made of PAH only andnot mixtures. We divided the reflectance properties ofthese samples into three parts with the non-exposed

samples in the wavelength range of 100-300 nm for theexperiments and compared the reflectance properties.
The reflectance properties of the Coronene samples
showed a significant decrease near 270 nm wavelengths
and a trend in the 210-280 nm wavelength range where
the attenuation of reflected light was more pronounced
in the longer wavelength range (Fig. 2).
This trend suggests that the wavelength
corresponding to the bottom of the depression may
shift to longer wavelengths due to space weathering.

PAH SamplessFig. 1. PAH samples installation diagram.

Fig. 2. The reflection characteristics of coronene
samples in the wavelength range of 160-300 nm.

[1] Salama, Farid. (2008). PAHs in astronomy - A review.
Proceedings of The International Astronomical Union.
251. 10.1017/S1743921308021960.

157 9 Ⅲ05-

Ⅲ- 5

Ⅲ -5. Life,BL7B
Earth and Planetary Sciences

BL7B

A study on Space weathering of Carbonaceous Meteorites by
Far-ultraviolet Spectroscopy
H. Akadama1, Y. Suzuki1, J. Yang2 and K. Yoshioka1,2

Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo,
Tokyo 113-0033, Japan2
Department of Complexity Science and Engineering, Graduate School of Frontier Sciences, The University of Tokyo,
Chiba 277-8561, Japan1

Ⅲ- 5

We study space weathering in Carbon-complex
asteroids by measuring the spectral shifts ofcarbonaceous meteorites due to weathering, focusing on
the far-ultraviolet (FUV; 50-200 nm). The feature of themeteorite materials on this spectral area has not beenmuch examined well.
Asteroids are believed to be well preserved inprimitive state since they have been left out of theplanetary formation process. Accordingly, they havebeen the focus of much attention as a clue to the natureof the early solar system. However, to analogize thepast state from the present observations, it is necessary
to understand the process of transformation such as
space weathering.
Space weathering is the dominant transformation
process on the surface of celestial bodies with thin
atmospheres, such as asteroids. This process is causedby solar photons, charged particles like energetic
electrons, and impacts by micrometeorites. The physicalproperties of such asteroid surfaces have been understood
mainly through spectroscopic observations in thevisible and infrared regions. However, the spectra inthese regions of Carbon-complex asteroids are
generally flat and have little characteristic shape [1]. On
the other hand, the UV spectra of organic compounds
vary remarkably with the degree of carbonization,suggesting that the UV region may be suitable for
evaluating space weathering effects on Carbon-complex
asteroids.
In this study, four types of carbonaceous chondrites
included in the meteorites were irradiated with FUV
light from the UVSOR BL7B, and the FUV spectra
before and after the irradiation were compared (Fig. 1).
To compare reflectance before and after UV irradiation,
relative reflectance with respect to a specific wavelength
was used.
As a result, bluing of the spectrum was observed in
the wavelength range of 50~200 nm (Fig. 2). This change
was the opposite of that observed for hydrocarbons
using polystyrene, and like that observed for bodies
with little or no organic matter, such as the lunar surface[2]. Since carbonaceous chondrites contain about 20
wt% of Fe, it is possible that a process of coating withFe of several hundred nm in size occurred by the UVirradiated surface, like that in the lunar surface.

Fig. 1. Light irradiation of a meteorite sample.

Fig. 2. Relative reflectance variation in a certain
carbonaceous meteorite (“Aguas Zarcas”). (Thehorizontal axis is wavelength [nm] and the verticalaxis is relative reflectance (normalized at red spots).
Blue and orange lines correspond to before and after
irradiation, respectively.)[1] S.J. Bus& R.P. Binzel, Icarus, 158 (2002) 146.
[2] A.Hendrix et al., Journal of Geophysical Research,
117 (2012) E12

15810 Ⅲ05-

Ⅳ

List of Publications

Ⅳ . List of Publications

List of Publications (2021)

D. Akazawa, T. Sasaki, M. Nagasaka and M. Shiga“X-ray Absorption Spectra of Aqueous Cellobiose: Experiment and Theory”, J. Chem. Phys., 156(2022) 044202.
K. Ali, H. Zen, H. Ohgaki, T. Kii, T. Hayakawa, T. Shizuma, H. Toyokawa, M. Fujimoto, Y. Taira and M.
Katoh“Three-Dimensional Nondestructive Isotope-Selective Tomographic Imaging of 208Pb Distribution
via Nuclear Resonance Fluorescence”, Applied Sciences, 11 (2021) 3415.

Ⅳ

D. Céolin1, H. Yuzawa, T. Saisopa, K. Klaiphet, J. Borsup, P. Songsiriritthigul and N. Kosugi“Substituent effects in aqueous solutions of carboxylate salts studied by x-ray absorption
spectroscopy at the oxygen K-edge”, J. Chem. Phys. 155, (2021) 014306.
O. Endo, F. Matsui, W. J. Chun, M. Nakamura, K. Amemiya and H. Ozaki“Nanographene growth from benzene on Pt(111)”, Surf.Sci., 711 (2021) 121874.

List of Publications

G. Germer, T. Ohigashi, H. Yuzawa, N. Kosugi, R. Flesch, F. Rancan, A. Vogt and E. Rühl
“Improved Skin Permeability after Topical Treatment with Serine Protease: Probing the Penetrationof Rapamycin by Scanning Transmission Xray Microscopy”, ACS Omega, 6 (2021) 12213.
K. Hagiwara, M. Ishikado, M. Horio, K. Koshiishi, S. Nakata, S. Ideta, K. Tanaka, K. Horiba, K. Ono, H.
Kumigashira, T. Yoshida, S. Ishida, H. Eisaki, S. Shamoto and A. Fujimori“Superconducting Gap and Pseudogap in the Surface States of the Iron-based Superconductor
PrFeAsO1-y Studied by Angle-resolved Photoemission Spectroscopy”, Phys. Rev. Research 3, (2021)
043151.

Y. Hikosaka“Multi-Electron–Ion Coincidence Spectrometer with a High-Efficiency Microchannel Plate Detector”,
J. Electron Spectrosc. Relat. Phenom., 255 (2022) 147158.
Y. Hikosaka, T. Kaneyasu, M. Fujimoto, H. Iwayama and M. Katoh“Reply to ‘Comment on “Coherent Control in the Extreme Ultraviolet and Attosecond Regime by
Synchrotron Radiation”, Nature Commun., 12 (2021) 3782.
T. Hirai, T. Kawai, Y. Harada and N. Ohno
“Formation of Cs3Cu2I5 Microcrystals in CsI Crystals through the Aggregation of Cu+ Ions”, Jpn. J.
Appl. Phys. 60 (2021) 075501.
S. Ideta, S. Johnston, T. Yoshida, K. Tanaka, M. Mori, H. Anzai, A. Ino, M. Arita, H. Namatame, M.
Taniguchi, S. Ishida, K. Takashima, K. M. Kojima, T. P. Devereaux, S. Uchida and A. Fujimori“Hybridization of Bogoliubov Quasiparticles between Adjacent CuO2 Layers in the Triple-Layer
Cuprate Bi2Sr2Ca2Cu3O10+δ Studied by Angle-Resolved Photoemission Spectroscopy”, Phys. Rev.
Lett. 127 (2021) 217004.
G. Ito, H. Kimura, D. Shiratori, K. Hashimoto, D. Nakauchi, M. Koshimizu, T. Kato, N. Kawaguchi and T.
Yanagida“Evaluation of Photoluminescence and Scintillation Properties of Eu-doped 20CsCl-20BaCl260ZnCl2 glasses by a melt quenching method”, J. Mater. Sci. Electron. 32 (2021) 8725.
M. Iwasawa, S. Kobayashi, M. Sasaki, Y. Hasegawa, H. Ishii, F. Matsui, S. Kera and Y. Yamada“Photoemission Tomography of a One-Dimensional Row Structure of a Flat-Lying Picene Multilayer
on Ag(110)”, J. Phys. Chem. Lett. (2022) 1512.
161

Ⅳ

Ⅳ . List of Publications
T. Kanomata, T. Awano and T. Ito“Optical Properties of the Antiferromagnetic Heusler Alloy Ru2CrGe”, Solid State Commun, 340(2021) 114525.
P. Kantuptim, H. Fukushima, H. Kimura, D. Nakauchi, T. Kato, M. Koshimizu, N. Kawaguchi and T.
Yanagida“VUV- and X-ray-Induced Properties of Lu2Si2O7, Y2Si2O7, and Gd2Si2O7 Single Crystals”,
Sensors and Mater. 33 (2021) 2195.
Y. Kebukawa, M. E. Zolensky, C. A. Goodrich, M. Ito, N. O. Ogawa, Y. Takano, N. Ohkouchi, K. Kiryu, M.
Igisu, T. Shibuya, M. A. Marcus, T. Ohigashi, J. Martinez, Y. Kodama, M. H. Shaddad and P. Jenniskens“Organic matter in carbonaceous chondrite lithologies of Almahata Sitta: Incorporation of previously
unsampled carbonaceous chondrite lithologies into ureilitic regolith”, Meteoritics & Planetary Science56, Nr 7, (2021) 1311.
Y. Kezuka, H. Murata, M. Yoshida, K. Eguchi, A. Nakahira and M. Tajika“Effects of Trace Si Impurities in Water on the Growth of Calcite Nanoparticles”, CrystEngComm, 24(2022) 747.
S. Makita, H. Matsuda, Y. Okano, T. Yano, E. Nakamura, Y. Hasegawa, S. Kera, S. Suga and F. Matsui“Contrast Inversion of Photoelectron Spectro-microscopy Image”, e-J. Surf. Sci. Nanotechnol., 19(2021) 42.
F. Matsui and H. Matsuda“Projection-type electron-spectroscopy collimator analyzer for charged particles and X-ray
detections”, Rev. Sci. Instrum., 92, (2021) 073301.
F. Matsui, S. Makita, H. Matsuda, E. Nakamura, Y. Okano, T. Yano, S. Kera and S. Suga
“Valence Band Dispersion Embedded in Resonant Auger Electrons”, J. Phys. Soc. Jpn., 90, (2021)
124710.
S. Mitsunobu, Y. Ohashi, H. Makita, Y. Suzuki, T. Nozaki, T. Ohigashi, T. Ina and Y. Takaki“One-Year In Situ Incubation of Pyrite at the Deep Seafloor and Its Microbiological and
Biogeochemical Characterizations”, Applied and Environmental Microbiolog, 87 (2021) e00977-21.
M. Nagasaka and N. Kosugi“Soft X-ray Absorption Spectroscopy for Observing Element-specific Intermolecular Interaction in
Solution Chemistry”, Chem. Lett. 50 (2021) 956.

Ⅳ

S. Nakata, M. Horio, K. Koshiishi, K. Hagiwara, C. Lin, M. Suzuki, S. Ideta, K. Tanaka, D. Song, Y.
Yoshida, H. Eisaki, and A. Fujimori“Nematicity in a cuprate superconductor revealed by angle-resolved photoemission spectroscopy
under uniaxial strain”, npj Quantum Mater. 6 (2021)86
Y. Nakayama, K. Sudo, N. Ohashi, S. Kera and Y. Watanabe“Interface electronic structure and valence band dispersion of bis(1,2,5-thiadiazolo)-p-quinobis(1,3dithiole) on polycrystalline Au electrodes”, Electron. Struct. 3 (2021) 024006.
J. Rodriguez, T. Ohigashi, C. Lee, M. Tsai, C. Yang, C. Wang, C. Chen, W. Pong, H. Chiu and C. Chuang“Modulating chemical composition and work function of suspended reduced graphene oxide
membranes through electrochemical reduction”, Carbon 185, (2021) 410.
E. Salehi and M. Katoh“Spatial structure and angular momentum of electro-magnetic wave radiated from a relativistic
electron moving on a spiral orbit”, J. Adv. Simulat. Sci Eng., 8 (2021) 87.

162

Ⅳ . List of Publications
H. Suga, K. Suzuki, T. Usui, A. Yamaguchi, O. Sekizawa, K. Nitta, Y. Takeichi, T. Ohigashi and Y.
Takahashi“A New Constraint on the Physicochemical Condition of Mars Surface during the Amazonian Epoch
Based on Chemical Speciation for Secondary Minerals in Martian Nakhlites”, Minerals, 11 (2021)
514.
I. Suzuki, Z. Lin, S. Kawanishi, K. Tanaka, Y. Nose, T. Omata and S. Tanaka“Direct Evaluation of Hole Effective Mass of SnS–SnSe Solid Solutions with ARPES Measurement”,
Phys. Chem. Chem. Phys. 24 (2022) 634.
S. Tsuru, B. Sharma, M. Nagasaka and C. Hättig
“Solvent Effects in the Ultraviolet and X-ray Absorption Spectra of Pyridazine in Aqueous Solution”,
J. Phys. Chem. A, 125 (2021) 7198.
J. V. V ́elez, Y. Chinc, M. Tsaid, O. J. Burtone, R. Wange, S. Hofmanne, W. Hsuf, T. Ohigashig, W. Pongd
and C. Chuang“Evidence of synergistic electrocatalysis at a cobalt oxide–graphene interface through nanochemical
mapping of scanning transmission X-ray microscopy”, Chinese Journal of Physics 76 (2022) 135.
H. Wang, J. Chiou, K. Chen, A. R. Shelke, C. Dong, C. Lai, P. Yeh, C. Du, C. Lai, K. Asokan, S. Hsieh, H.
Shiu, C. Pao, H. Tsai, J. Yang, J. Wu, T. Ohigashi and W. Pong
“Role of Interfacial Defects in Photoelectrochemical Properties of BiVO4 Coated on ZnO
Nanodendrites: Xray Spectroscopic and Microscopic Investigation”, ACS Appl. Mater. Interfaces 13,(2021) 41524.
S. Yamasuso and T. Kawai“Electronic states and relaxation dynamics of Au─ centers in RbCl crystals”, J. Lumin. 236 (2021)
118094.
M. Yoshida, M. Miyahara, H. Suga, A. Yamaguchi, N. Tomioka, T. Sakai, H. Ohfuji, F. Maeda, I. Ohira, E.
Ohtani, S. Kamada, T. Ohigashi, Y. Inagaki, Y. Kodama and N. Hirao“Elucidation of impact event recorded in the lherzolitic shergottite NWA 7397”, Meteoritics &Planetary Science (2021) 1.

Ⅳ

163

UVSOR User 8

Ⅴ

Workshops

Ⅴ . Workshops

UVSOR Symposium 2021
Date: November 5, 2021
Place: Zoom Conference
November 5th (Fri.)
10:35 – 10:40

Opening Remark<Session 1, Chair: T. Ohigashi (UVSOR)>
10:40 – 11:00

Development of Multilayer Coated Mirror for the Next Earth Mission
L. Huiyang (Univ. of Tokyo)

11:00 – 11:20

Current-Induced Insulator-to-Metal Transition of SmS
S. Tatsukawa (Osaka Univ.)

11:20 – 11:40

Title of the Presentation (gothic, 11pt)
K. Yamanoi (Osaka Univ.)

Ⅴ

11:40 – 12:00	‌Development of Reflection XMCD Measurement Setup for the Investigation of Inner
Structures of Magnetic Thin Films at UVSOR BL4B

Workshops

K. Yamamoto (IMS)
12:00 – 13:00

Lunch Break<Session 2, Chair: K. Tanaka (UVSOR)>
13:00 – 13:20

Electronic States of Novel Dirac Semimetals Studied by High-Resolution ARPES
K. Nakayama (Tohoku Univ.)

13:20 – 13:40

The Topological Electronic Structure of the Interface Between α-Sn and InSb
T. Nakaya (Osaka Univ.)

13:40 – 14:00

The Photoelectron Momentum Mapping of Highly Oriented Organic Thin Films
M. Iwasawa (Univ. of Tsukuba)

14:00 – 14:20

Measurement of the Electronic State of η-Mo4O11 Using a Momentum Microscope
T. Kobayashi (Osaka Univ.)

14:20 – 14:30

Break<Session 3, Chair: Y. Taira (UVSOR)>
14:30 – 14:50	‌LCS Gamma-Ray Beams Utilization for the Isotope Selective NRF-CT Imaging in UVSORIII
K. Ali (Kyoto Univ.)
14:50 – 15:10	‌Charge Distribution in Delithiated LiCoO2 Particles Visualized by Soft X-Ray
Spectromicroscopy
W. Zhang (Univ. of Tokyo)
15:10 – 15:30

Mesoscopic Structure Analysis by Resonant Soft X-Ray Scattering
H. Iwayama (IMS)

15:30 – 15:50 	Time-Resolved Spectroscopy of Fast Scintillators with VUV Excitation
M. Koshimizu (Tohoku Univ.)

16:00 – 17:00

Discussion and Closing Remark
S. Kimura (Osaka Univ.)

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ⅤⅤ . Workshops
17:00 – 19:00

Poster Session

Poster Session
P01

Photoelectron Wave Packet Interference Using a Tandem Undulator
T. Kaneyasu (SAGA- LS)

P02	‌Photon Counting Experiments of Young’s Double-Slit Interference Using Undulator Vortex
Radiation
S. Wada (Hiroshima Univ.)
P03

Energy-Dependence of Photoelectron Circular Dichroism of Chiral Molecules
H. Kohguchi (Hiroshima Univ.)

P04

Photoluminescence Properties and luminescence Mechanism of Cs2Hf(Br, X)6
C. Fujiwara (Tohoku Univ.)

P05

Operando XAFS Observation of Water Splitting Electrocatalysts at UVSOR BL3U
M. Yoshida (Yamaguchi Univ.)

P06	‌Elucidation of the Function of Carbonate Ions on the Cobalt Carbonate Catalysts Using
Operando Observations
K. Harada (Yamaguchi Univ.)
P07	‌Operando Observation of Active Site for the Nickel Carbonate Water Splitting Catalyst
Induced by the Electrolyte Adsorption Ions
Z. Li (Yamaguchi Univ.)
P08

The Structure Analysis of Soft Matter by Resonant Soft X-Ray Scattering
Y. Takanishi (Kyoto Univ.)

P09	‌Solvent-Induced Transition of Polymorphological Chiral Supermolecular Architectures in a
Bent-Core Liquid Crystal Dimer
F. Araoka (RIKEN)
P10	‌XAS Measurements of Sugar Molecules in Liquid Phase: Interaction Between Sugar
Molecules and Solvent
D. Akazawa (Univ. of Tokyo)
P11	‌Intermolecular Interactions of the Acetone-Water Binary System Studied by Soft X-Ray
Absorption Spectroscopy
C. Sugahara (Hiroshima Univ.)
P12	‌Efficient Multielectron-Ion Coincidence Measurement with a Magnetic Bottle Electron
Spectrometer

Ⅴ

Y. Hikosaka (Toyama Univ.)
P13

Efforts to Reduce the Photon Energy Drift at BL5B
H. Zen (Kyoto Univ.)

P14

Local Valence Transition of SmS Induced by Alkali Metal Adsorption
T. Nakamura (Osaka univ.)

P15	‌Angle-Resolved Photoemission Study of Solid Electrolytes LixLa(1-x)/3NbO3 Bulk Single
CrystalR. Yamamoto (Nagoya Univ.)

168Ⅴ . Workshops
P16	‌Development of Photocathodes for Accelerator Beam Source by Coating with AtomicallyThin Two-Dimensional Nanomaterials
K. Kouyama (Nagoya Univ.)
P17

Angle-Resolved Photoemission Study of TPP[FePc(CN)2]2
T. Hoshina (Nagoya Univ.)

P18	‌Operando Measurements of THz, Infrared and Visible Reflectance Spectra of SmS Under
Current and Light Irradiation
H. Watanabe (Osaka Univ.)
P19

Momentum-Resolved Resonant Photoemission Spectroscopy of TiSe2
S. Tanaka (Osaka Univ.)

P20	‌Resonant Photoemission Spectroscopy of Highly Oriented Coronene Monolayer Using
Photoelectron Momentum Microscope
Y. Hasegawa (Ritsumeikan Univ.)
P21

Measurement of Complex Reflective Index of Diamond Substrate
M. Horiba (Fukui Univ.)

P22

Impact of Weak Interaction on the Electronic Structure at the Pentacene/Graphite Interface
Y. Hasegawa (Ritsumeikan Univ.)

P23	‌Angle-Resolved Photoemission Study of Antiferromagnetic i - MAX Phase Compound(Mo2/3Dy1/3)2AlC
T. Sugimoto (Nagoya Univ.)
P24	‌Investigations on the Band Structures and Anisotropic Couplings of Electrons with MolecularVibrations in Organic Single Crystal Rubrene
K. Fukutani (IMS)
P25

Lattice Design Study of UVSOR-IV
E. Salehi (IMS)Ⅴ

169

Ⅴ . Workshops

The 4th workshop on prospects and construction plan of the next generationsynchrotron radiation facility
Date: November 4, 2021
Place: Zoom Conference
November 4th (Thu.)
9:30 – 9:35

Greetings from Guest
Section Chief from MEXT, A. Watanabe

9:35 – 10:15

Opening Remark
UVSOR Director, S. Kera

10:15 – 10:20

Break

10:20 – 12:00

Beamline Conception ①
Present Status and Future Plan of Soft X-Ray Absorption and Scattering at BL3U
M. Nagasaka (IMS)
Future Prospects for Soft X-Ray Absorption and Scattering
J. Miyawaki (QST)
Current Status and Prospects of Infrared Microscopy Using Infrared Synchrotron Radiation
Y. Ikemoto (JASRI)
Current Status and Development of Irradiation (BL1U)
Y. Taira (UVSOR)
Prospects of Irradiation and FEL
I. Matsuda (Univ. of Tokyo)

12:00 – 13:30

Lunch Break

13:30 – 15:50

Beamline Conception ②
Present Status and Future of VUV Spectroscopy in UVSOR
M. Kitaura (Yamagata Univ.)
Present and Future of Photoelectron Momentum Microscope + SpinF. Matsui (UVSOR)
Future Prospect of Spin-Resolved Photoemission Electron Microscopy and Spectroscopy
K. Yaji (NIMS)
Current Status and Developments of ARPES at UVSOR
K. Tanaka (UVSOR)
Future of ARPES: Putting More Information on ARPES

Ⅴ

K. Kuroda (Hiroshima Univ.)
Current Status and Future of Soft X-Ray Imaging
T. Ohigashi (UVSOR)
Future of Soft X-Ray Imaging
Y. Takahashi (Tohoku Univ.)
15:50 – 16:00

Break

16:00 – 16:20

Latest Results from Design Study on New Light Source
M. Katoh (UVSOR)

170

Ⅴ . Workshops
16:20 – 17:00

Panel Discussion“Requests for the Construction Plan”

	‌(Panelist : J. Okabayashi, M. Katoh, M. Kitaura, S. Kimura, Y. Hikosaka andH. Yamane)Ⅴ

171

Ⅴ . Workshops

2021 IMS Open House Event
IMS is open to the public once every three years in rotation with the other two Okazaki
institutes of National Institutes of Natural Sciences. It was held online on October 23, 2021.
Details can be seen in the following web site:
https://www.ims.ac.jp/koukai2021/.
The livestreamed video can be seen athttps://www.youtube.com/watch?v=24JmaV8Fbgo,
which spans about 6 hours, including a molecular science forum and virtual tours of facilities
and laboratories.
For the UVSOR tour (which is included in the above video),
see https://www.youtube.com/watch?v=WqIFnMnKBTc&t=360s.

The presentation of the forum was given by Dr. Takuji Ohigashi about Hayabusa2 returned
sample analysis:seehttps://www.ims.ac.jp/koukai2021/info/#microⅤandhttps://www.youtube.com/watch?v=AnchMBTwHBw.

172

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gEditorial Board：H. Matsuda

hK. Tanaka

M. SakaiM. Ishihara