PREFACE
This annual report reviews the research activities of the Laboratory of Advanced
Science and Technology for Industry (LASTI) in the academic year of 2015 which is from
April 2015 to March 2016) including research activities using NewSUBARU light sourceat the site of SPring-8 and other research activities of the micro and nanoscale arecarried out energetically in the building of Center for Advanced Science and Technology(CAST) II.
The annual report describes that topics of the NewSUBARU research activities of thisyear including research and development of gamma ray application at BL2 beamline,
the next generation lithography using Extreme Ultraviolet at BL3, BL9B, BL9C, andBL10 beamlines, and Nanoimprint Lithographic Technology at CAST, LIGA process
technology at BL2 and BL11 beamlines, and chemical analysis using soft X-ray
absorption fine structure at (BL5, BL9A, and BL7 beamlines and soft X-ray emission
spectroscopy at BL5 and BL9A beamlines in soft x-ray energy region.
Most of our research activities are being conducted in collaboration research works
with industries, government research institutes, and other universities.
We will continue to respond to the community’s demand by offering new science andtechnology.

Takeo Watanabe

Director of Laboratory of
Advanced Science andTechnology for Industry,
University of Hyogoi

ii

Stuff of LASTI（In front of Advanced Research Building）

iii

The Organization ofLaboratory of Advanced Science and Technology for Industry
University of Hyogo
The organization
Director

Steering
Committee

Department ofLight and Particle Science and Technology

Department ofLight Application for Advanced Technology

�Advanced Photon System
�Beam Physics
�Nanostructure Science and Technology
�Guest Chair

�Nano-science and Technology utilizing
Synchrotron Radiation
�Nano-Micro System
�Bio-Medical Technology (to be established)�Guest Chair

Staff (FY 2015)
Research and faculty staff
MIYAMOTO Shuji, Professor, Director
MATSUI Shinji, Professor
KANDA Kazuhiro, Professor
UTSUMI Yuichi, Professor
WATANABE Takeo, Professor
NIIBE Masahito, Associate Professor
SHOJI Yoshihiko, Associate Professor
HARUYAMA Yuichi, Associate Professor
YAMAGUCHI Akinobu, Associate Professor
AMANO Sho, Research Associate
HASHIMOTO Satoshi, Research Associate
HARADA Tetsuo, Research Associate
OKADA Makoto, Research Associate

Administrative staff
HAMAGAMI Akiyuki, General Manager
KOBORI Kazuyuki, Manager
KURODA Takashi, Chief
KAMIYA Miki, CAST
KANATANI Naoko, NewSUBARU
YAMAMOTO Keiko, CASTYOKOYAMA Yuka, CASTYANO Ayumi, CAST
FUJIMAKI Hisae, CASTYAMADA Miki, CASTYAMAMOTO Mako, NewSUBARU
KUSUMOTO Kumi, CASTMORIGUCHI Miyuki, Harima Forum of
Science and Technology for 21st Century

Specially appointed staff
MOCHIZUKI Takayasu, Professor
KINOSHITA Hiroo, Professor
KUDOU Hiroto, Associate Professor
NAGATA Yutaka, Assistant Professor
IYOSHI Syuzou, Resercher

Liaison staff
FUKADA Noboru, NewSUBARU
UMESAKI Masanori, NewSUBARUISHIKAWA Kazuko, NewSUBARU
MINAMIYAMA Yasuto, NewSUBARUKOTAKA Takuya, NewSUBARU

Guest staff
OHKUMA Haruo, Professor
ASANO Yoshihiro, Professor
FUKUSHIMA Sei, Professor
Contact address

Advanced Research Building
3-1-2 Kouto, Kamigori-cho, Ako-gun, Hyogo, 678-1205 JAPAN.
T:+81-791-58-0249 F:+81-791-58-0242
NewSUBARU Synchrotron Radiation Facility
1-1-2 Kouto, Kamigori-cho, Ako-gun, Hyogo, 678-1205 JAPAN.
T:+81-791-58-2503 F:+81-791-58-2504
Web URL http://www.lasti.u-hyogo.ac.jp/,
http://www.lasti.u-hyogo.ac.jp/NS/
e-Maillasti@lasti.u-hyogo.ac.jp
Accesshttp://www.lasti.u-hyogo.ac.jp/NS-en/access/iv

CONTENTS
PREFACEORGANIZATION of LASTIPart 1. Current Status of NewSUBARU and Other Light Source
NewSUBARU Storage Ring
Shuji Miyamoto (LASTI/University of Hyogo)

1

NewSUBARU Beamlines
Kazuhiro Kanda (LASTI/University of Hyogo)

3

Recent Improvements on the Beam Operation of the NewSUBARU Electron Storage Ring
S. Hashimoto, Y. Takemura1, H. Takeuchi1, K. Morisato1, and S. Miyamoto(LASTI, University of Hyogo, 1JASRI SPring-8)

10Simulation Study on Optimization of the Beam Dynamics at LEENA Accelerator
Satoshi Hashimoto, Karin Kobayashi, and Shuji Miyamoto (LASTI, University of Hyogo)

11High Average Power Soft X-ray in the Water Window from Ar Laser Plasma
Sho Amano, (LASTI/Univ. Hyogo)

14

Present Status of BL05A performance
T. Hasegawa1, S. Fukushima2,3, T. Kotaka3 and K. Kanda3(1Synchrotron Analysis L.L.C. , 2NIMS, 3LASTI/University of Hyogo)

16

Development of the Control System of Double Multilayers monochromator in NewSUBARU BL07A
M. Okui1,2, I. Kikuchi2, N. Yano2, A. Watanabe2, N. Murayama2, S. Fukushima1,3 and K. Kanda1(1LASTI/Univ. Hyogo, 2Kohzu Precision Co., Ltd., 3NIMS)

18

Performance of BL07A Installed New Multilayered-Mirror Monochromator
S. Tanaka1, N. Yato2, M. Okui1,2, S. Fukushima1,3, and K. Kanda1(1LASTI/Univ. Hyogo, 2Kohzu Precision Co., Ltd., 3NIMS)

20

Adjustment of the Equipment for the measurement of Ultra-soft X-ray Fluorescence Spectrum on
BL07A
S. Fukushima1,2, H. Takamatsu1, S. Tanaka1, K. Kanda1 (1LASTI/Univ. Hyogo, 2NIMS)
Installation of Silicon Drift Detector for PFY-XAFS measurement of insulating materials in BL-09A
Shigeaki Uemura1, Junji Iihara1, Takashi Yajima2, Masahito Niibe2(1Sumitomo Electric Industries, 2Ltd., Sumitomo Riko Co. Ltd., 3LASTI/Univ. Hyogo)

v

22

25

Development of an Analysis Station for Soft X-ray Absorption Spectroscopy in BL10
Y. Muramatsu1, A. Tueda1, T. Uemura1, K. Nambu1, T. Ouchi1, T. Harada2, T. Watanabe2,
H. Kinoshita2 (1Eng./Univ. Hyogo, 2LASTI/Univ. Hyogo)

27

Soft X-ray Absorption Spectroscopy (XAS) and X-ray reflectivity (XRR) analysis system in BL10
Y. Muramatsu1, A. Tueda1, T. Uemura1, K. Nambu1, T. Ouchi1, T. Harada2, T. Watanabe2,
H. Kinoshita2 (1Eng./Univ. Hyogo, 2LASTI/Univ. Hyogo)

29Part 2. Research Activities
Development of LCS Gamma-Ray Simulation Code and GUI Application
Satoshi Hashimoto, Takuya. Matsumoto, and Shuji Miyamoto (LASTI/University of Hyogo)

33

Measurements of Neutron Energy Spectra Depending on the Emission Angle due to Photo-nuclear
reaction using LCS photons
Y. Asano, T. Sanami, H. Nakashima, Y. Kirihara, T. itoga, Y. Namito, A. Takemoto, M.
Yanaguchi, S. Miyamoto(RIKEN SPring-8 Center, High Energy Accel. Res. Org., JAEA, JASRI, LASTI/Univ. Hyogo)
Photoneutron Reactions in Nucleosynthesis
Hiroaki Utsunomiya (Konan Univ.)

34

37

Total and Partial Photoneutron Cross Section Measurements by Direct Neutron-multiplicity Sorting
39
Hirokaki Utsunomiya, and the Phoenix Collaboration (Konan Univ.)
First Characterization of Time Projectionchamber as a High-performance Gamma-ray Pair
Creation Telescope and Polarimeter

41

Denis Bernard (LLR, Ecole Polytechnique & CNRS/IN2P3, France)
Measurements of Nuclear Resonance Fluorescence on 52 Cr with a Linearly Polarized Photon Beam at
BL01

45
1

1

2

3

3

T. Shizuma , T. Hayakawa , F. Minato , I. Daito , H. Ohgaki , S. Miyamoto

4(1National Inst. Quantum & Radiol. Sci. & Technol., 2JAEA, 3Kyoto Univ., 4LASTI/Univ. Hyogo)
Azimuthal Anisotropy of Neutrons in 56 Fe(polarized γ, n) 57 Fe Reactions at BL01
1

1

2

2

2

47
2

T. Hayakawa , T. Shizuma , S. Miyamoto , S. Amano , A. Takemoto , M. Yamaguchi , K.
Horikawa2, H. Akimune3, S. Chiba4, K. Ogata5, M. Fujiwara5 (1National Inst. Quantum & Radiol.
Sci. & Technol., 2LASTI/Univ. Hyogo, 3Konan Univ., 4Tokyo Instit. Technol., 5Osaka Univ.)
The film modification of Si-containing hydrogenated DLC films by the soft X-ray irradiation
Shotaro Tanaka1, Ryo Imai1, Takayuki Hasegawa2 and Kazuhiro Kanda1(1LASTI/Univ. of Hyogo, 2Synchrotron Analysis L.L.C.)

vi

49

Surface modification Processes of Highly Hydrogenated Diamond-Like Carbon Thin Films by Soft Xray Irradiation

52
1

1

2

2 1

2

K. Kanda , R. Imai , K. Komatsu , H. Saitoh ( LASTI/Univ. Hyogo, Nagaoka Univ. of Technol.)Refractive-index Modifications in Silica-Bases Films by Undulator Radiation with Multilayer
Spectrometer
K Moriwaki1, G. Kimura1, K. Kanda2 and S. Matsui2 (1Kobe Univ.,2LASTI/Univ. of Hyogo,)

55

Effect of the Soft-X-ray on the Surface of Fluorinated DLC Film
H. Takamatsu, M. Okada, M. Niibe, and K. Kanda (LASTI/ Univ. Hyogo)

57

Evaluation of Damage in an Organic Thin Film with Cluster Ion Sputtering
S. Fujita, Y. Nohara, M. Ohno, Y. Haruyama (Nissan Chemical Industries, Lid., LASTI/Univ.
Hyogo)

59

Molecular Orientation in Photoreactive Liquid Crystalline Polymer Films Observed by NEXAFS
Y. Haruyama, Y. Taniguchi, M. Kondo, N. Kawatsuki, M. Okada, S. Matsui(LASTI/Univ. Hyogo, Eng./Univ. Hyogo)

62

A large Takeoff-angle Dependence of C-K Emission Spectra Observed in Highly Oriented Pyrolytic
Graphite
Noritaka Takehira1, Masahito Niibe1, Yuma Araki1, Takasshi Tokushima2,(1LASTI/Univ. of Hyogo, 2RIKEN Spring-8 Center)
Irradiation Effect of Oxygen Plasma to TiO2 Thin Films
Yuma Araki1, Masahito Niibe1, Retsuo Kawakami1, Noritaka Takehira1, Yoshitaka Nakano3(1LASTI/Univ. of Hyogo, 2Tokushima Univ. 3Chubu Univ.)
Modification of Horizontally Aligned Multi-walled Carbon Nanotube Films by Ar Ion beam
Irradiation and Its Characterization by Soft X-ray Spectroscopy
S. Honda1,7, M. Niibe2, M. Terasawa2, R. Hirase3, H. Yoshioka3, H. Izumi3, K. Niwase4,
E. Taguchi3, T. Harada2, Y. Muramatsu1, K.-Y. Lee6 and M. Oura7(1Eng./Univ. Hyogo. 2LASTI/Univ. Hyogo, 3Hyogo Pref. Instit. Technol., 4Hyogo Univ. Teacher
Education, 5Osaka Univ. 6Taiwan Univ. Sci. & Technol., 7RIKEN SPring-8 Center)
Development of High-Reflective W/Si-multilayer Diffraction Grating for the Analysis of Fluorine
Materials
M. Kuki1, T. Uemura1, M. Yamaguchi1, T. Harada1, T. Wtanabe1, Y. Muramatsu2, and H.
Kinoshita1 (1LASTI/Univ. Hyogo, 2Eng./Univ. Hyogo)

64

67

69

71

Development of the Molecular Orientation Analysis by Soft X-ray Absorption Spectroscopy
E. Takahashi1, K. Imanishi1, S. Suehiro1, Y. Suzuki2, Y. Ota3, Y. Muramatsu3(1Sumika Chem. Anal. Service Ltd., 2Yamagata Univ. 3Eng./Univ. Hyogo)

77

Local Structure Analysis of Graphitic Carbon Materials by X-ray Absorption Spectroscopy
K. Murayama1, T. Haruyama1, R. Kazihara1, Y. Muramatsu2(1MIKUNI COLOR, Ltd. 2Univ. Hyogo)

79

vii

Soft X-ray Absorption Spectroscopy of Oxygen in Rubber-Brass Adhesive Layer
T. kakubo1, N. Amino1, K. Nanbu2, Y. Muramatsu2 (1Yokohama Rubber Co. Ltd., 2Univ. Hyogo)

81

Analyses of Surface State of Detonation Nanodiamond
M. Nishikawa1, M. Liu1, A. yamakawa1, Y. Muramatsu2 (1Daicel Corporation, 2Eng./Univ. Hyogo)

83

Analysis of the Carbon Black by Soft X-ray Absorption Spectroscopy

85

A. Inoue1, M. Fujisue2, T. Hattori1, T. Takakura1, T. Inoue1, K. Murayama3, Y. Mutamatsu3(Mitsubishi Chemical Corp., Mitsubishi Rayon Co. Ltd, Univ. Hyogo)
Development of Transmission Grating for EUV Interference Lithography of 1X nm HP
T. Hukui, H. Tanino, Y. Fukuda, M. Kuki, T. Watanabe, H. Kinoshita, and T. Harada(LASTI,/University of Hyogo)

87

Trial Fabrication of PTFE-filled E-plane Waveguide Coupler using SR Etching Process
Mituyoshi. Kakeuchi1, Akinobu. Yamaguchi2, Yuichi. Utsumi2, Isao. Ohta3(1Okayama Pref. Univ., 2LASTI/Univ. Hyogo, 3Univ. Hyogo)

92

Lab-on-a-CD to Implement High Precise Unit Chemical Operation for Immunoassay
M. Takeuchi1 Y. Arisue1, Y. Ukita2, C. Kataoka3, T. Kobayashi4, A. Yamaguchi1, Y. Utsumi1(1LASTI/Univ. Hyogo, 2Univ. Yamanashi, 3Carbuncle Bio Sci. Tech. LLC, 4National InstituteTechnol. Tsuyama College)

94

Proposal of Direct Digital Manufacturing Approach for Production of Microfluidic Devices
Yoshiaki Ukita1, Akinobu Yamaguchi2, Yuichi Utsumi2 (1Univ. Yamanashi, 2LASTI/Univ. of Hyogo)

98

Synthesis of Particles Extracted from Aqueous Solution Induced by X-ray Radiolysis Using
Synchrotron Radiation
Akinobu Yamaguchi1, Ikuo Okada2, Takao Fukuoka1, Yuichi Utsumi1(1LASTI/Univ. Hyogo, 2SR Research Center Nagoya Univ.)
Negative Tone 50 nm Line and Space Pattern Fabrication by Electron Lithography using NEB-22

100

102

Makoto Okada and Shinji Matsui (LASTI/Univ. Hyogo)

List of publications(1) Papers

107(2) International meetings

112(3) Academic degrees

118

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x

NewSUBARU Storage Ring
Shuji Miyamoto

Storage Ring Parameters
Figure 1 shows the layout of NewSUBARU
Synchrotron Light Facility and the electron
injection linac of SPring-8. NewSUBARU is
installed in square building of 63m☓85m. Electron
beams are injected through the transport line
L 4 B T. T h e m a c h i n e p a r a m e t e r s o f t h e
NewSUBARU storage ring are listed in Table I.
Although the machine condition remains the same,
some of the values are revised according to the newmodel calculation.

Operation Status
The ring has two user-time operation modes, 1.0
GeV top-up operation mode and 1.5 GeV current
decay operation mode. The basic operation time is
9:00 - 21:00 of weekdays. Monday is used formachine R&D, Tuesday is for 1.5 GeV user time,
Wednesday and Thursday are for 1.0 GeV top-up
user time, Friday is for 1.0 GeV or 1.5 GeV user
time. Night period or weekend is used for machine
study and user time with the special mode, such asa single bunch operation and a changing theelectron energy, if necessary.

Table I Main parameters of the NewSUBARU
storage ring.

beam down time
(5.7 %)

machintuning(13.7 %)

Circumference
118.73 m
Lattice
DBA+Inv. bending
Number of bending mag. 12
Radius of curvature
3.217m
RF frequency
499.955 MHz
Betatron tunes
H: 6.30, V:2.23
Bunch length (sigma)
33ps (normal operation)
Harmonic number
198
Radiation loss per turn 33.4 keV (@1GeV)Electron energy
1.0GeV
1.5GeV
Mode
TopUp
Decay
Natural energy spread
0.047%
0.072%Natural emittance
50 nm
112 nmStorage current
300 mA
350mA

machinestudy(6.9 %)

124h
297h
149h

user time(73.7 %)
1,591hFigure 2 Operating time breakdown of
NewSUBARU in FY2015.

SPring-8 Linac

0 10 20 30 m

BM
X=-163234 .70
Y= 55087.03
BM
X=-175434 .70
Y= 57387.03

BM
X=-131234 .70
Y= 57387.03
BM2
BM1

N

SPring-8 Booster
Synchrotron
QD
QD
BM-250Beam
Window
BDBM
X=-124947 .54
Y= 64862.03

L4BT

NewSUBARU

Figure 1 Layout of NewSUBARU Synchrotron Light Facility.
Electrons are injected from SPring-8 linac through beamtransport line L4BT. Injection electron energy is 1 GeV.

1

Machine Study and Special User Time
Table III shows the list of machine studies in FY
2013. Most of the study reports are open to the public
on the home page of NewSUBARU.
(http://www.lasti.u-hyogo.ac.jp/beam_physics/
NewSUBARU.html).

The total machine time in FY2015 was 2161 hrs,
97% of that of FY2014, including the beam downtime. Figure 2 shows the breakdown. The beam
down time includes not only the down by a failure,but also off-beam periods by a beam abort or others
due to the beam instability. The down time due tothe machine trouble was 5.7 %, is long comparing
with recent years. Main cause of this is the aging of
the equipment such as electronic components ofcontrol devices.

Accelerator Improvements
Figure 3 shows recent filling pattern of the electron
bunch in the storage ring. (a) is a filling model forhigh current long life operation and (b) is an example
of measured filling pattern. Lowest current bunch
relative to the model filling is selected as a injection
bucket at top-up operation. (c) is a single bunch
operation at special user time.

Machine Trouble
The machine troubles in FY2015 are listed in Table
II. The rate of hardware troubles were increasing due
to the aging.

Table II Machine troubles in FY2016.
Group

Failure / trouble

beam down time (hr)Operation

Beam loss by an instability

3.65

RF

Circulator arc & Tuning

8.57

MagnetElectrosity

Magnet interlock failure
power cubicle failure
lightning power failure

102.653.3
5.3

Table III List of machine studies and special user mode in FY2016.
(unit is an operation shift = 12 hrs)(mA)

R & D theme and special user mode
Laser Compton scattering γ-ray
Commissioning of beam profile monitor port SR2
Tuning of 1.5 GeV acceleration
Beam measurements by AC sextapole magnet

(mA)

(a)

(b)

2.5
2.0
1.5
1.0
0.5
0.0
2.5
2.0
1.5
1.0
0.5
0.0

(mA)

30

(c)

0

responsible person
S.Miyamoto
Y.Shoji
S.Hashimoto & M Niibe
Y.Shoji

200 ns100

operation shifts
58
3
10
5

300

400
2015/12/18 11:59

0

200 ns

100

300

400

300

400

I=30mA

20
10
0

100

200 nsFigure 3 Filling pattern of the electron bunch in the storage ring. Horizontal axis shows a lap timeof electron circulation. (a) Model of filling pattern at user time. (b) Measured filling pattern at user
time. (c) Single bunch operation at special user time.

2

Beamlines
Kazuhiro Kanda
LASTI, University of Hyogo
beamline for the usage of the thickness measurement of the
carbon contamination originated to the resist outgassing
during the EUV exposure.
BL02 beamline was constructed for the usage of LIGA
in 2003.
BL05 beamline was constructed in response to a demandin the industrial world in 2008, which is the enhancement of
the analysis ability in the soft X-ray region with thedevelopment of nanotechnology.
The arrangement of the beamlines in the NewSUBARU
synchrotron radiation facility is shown in Fig.1.

Total nine beamlines are operating in the NewSUBARU
synchrotron facility. Four beamlines of BL01, BL03, BL06
and BL11 were constructed until 1999. Three beamlines ofBL07, BL09 and BL10 were started the operation from 2000.
BL03B beamline branched from the BL03 beamline
propose for the usage of the EUVL (extreme ultraviolet
lithography) microscope for the EUVL finished mask
inspection.
BL09B beamline branched from BL09 beamline for theusage of the usage of the EUV interference lithography toevaluate. And BL09C beamline branched from BL09B

Fig. 1 Beamline arrangement in NewSUBARU.

3

I. BL01
BL01 is a beamline for research and developing newlight sources. This beamline is one of two long straightsection on NewSUBARU. Optical klystron was installed at
this straight section. Upstream side of this beamline(BL01B) is intended to be used for visible and infrared light
generated from free electron laser (FEL) or synchrotron
radiation (SR). Downstream side of this beamline (BL01A)
is used for laser Compton scattering gamma-rays source.
Gamma-ray beamline hutch just outside of the storage ringtunnel was constructed in 2004 for gamma-ray irradiation
experiments. Specification of this gamma-ray sources arelisted in Table 1.

*Gamma-ray beam divergence : 0.5 mrad
New gamma-ray irradiation hutch "GACKO" wasinstalled at BL01A, collaborating with Konan University.
Table 2 shows the specification of “GACKO”.
Table 2. Specification of “GACKO”
Maximum gamma-ray power
0.33 mW
Maximum gamma-ray energy
1.7 MeV - 73 MeV
CO2 laser, wavelength/power
10.59 µm / 10W
1-1.7MeV gamma-ray flux
2×10^7γ/sec@10W/300mA
Nd:YVO4 laser,
1.064 µm/ 30W,
wavelength/power
0.532 µm/20W
10-17 MeV gamma-ray flux
5×10^7γ/sec@30W/300mA

Table 1. Specification of BL01 gamma beam
CO2 laser
Gamma energy : 1.7 - 4 MeV
Gamma flux* : 9 x106 γ/s
10.52 m
: 6 x105 γ/s (1.5-1.7 MeV)
5W
(with 3mmφ collimator)
Gamma energy : 17 - 40 MeV
Nd laser
Gamma flux* : 7.5 x106 γ/s
1.064 m
: 3 x105 γ/s (15-17 MeV)
0.532 m(with 3mmφ collimator)
5W*Electron beam energy : 1-1.5 GeV*Electron beam current : 250 mA

II. BL02
cylindrical mirror) and Be film filters. The horizontal angleof the outgoing SR could be obtained up to 12.5 mrad, whichcorresponds to the horizontal size of 220 mm (A4 horizontalsize) at the exposure position. The second characteristic
performance of the beamline is the high efficiency
differential pumping system. This was necessary for
maintain the vacuum difference between the storage ring(<10-9 Pa) and the end-station (<10-9 Pa) at which gasses for
substrate cooling will be introduced in the exposure
apparatus.
The flexibility for the shapes and functions of
microstructure will be enlarged by achieving 3D
microfabrication process using multi step exposure atvarious configuration between x-ray mask and substrates.
The relative positions between x-ray mask and substrates,
tilt and rotation angle to the SR incident direction can be
moved simultaneously during SR exposure using 5 axis
stages. The movement of each axis is controlled by the PC
in terms of the scanning speeds, scanning length, andrepetition number. In order to decrease the heat load ofsample substrate suffered during SR irradiation helium
introduction and substrate cooling mechanism were also
equipped. Specification of spectrometer is listed in Table 3.

The LIGA (abbreviated name of Lithogaphic,
Galvanoformung and Abformung) process which consistsfrom deep x-ray lithography, electroforming, and molding
process is one of the promising candidates for such 3D
micofabrication. More than hundreds aspect ratio for
microstructure can be attained by the usage of the higher
energy x-rays (4-15 keV) from synchrotron radiation (SR)with deeper penetration depth to the photosensitive resist. In
this system we have succeeded to enlarge the exposure area
up to A4 size and the fabrication dimension from submicron
to millimeter by varying the energy of the x-ray source inaccordance with the size of desired microparts.
Microstructure with high aspect ratio over several hundred
will be achieved using the x-rays over 10 keV since highenergy x-ray has deep penetration depth to the photosensitive resist materials. Whereas, in the case oflithography for low energy x-rays from 1 keV to 2 keV,submicron structures with high aspect ratio will be achieved
using the x-rays mask with precise line-width and thinnerabsorber, since low energy x-rays has low penetration depth.
Based on this principle, the beamilne for x-ray exposure
have constructed with continuous selectivity of x-rays from100 eV to 15 keV by using the x-ray mirrors (plane and4

Table 3. Specification of the LIGA exposure system
OpticsPlane and cylindrical mirror, Be filters
Exposure energy
100 - 2 keV, and 4 – 15 keV
Exposure method
Proximity and multi-step exposure
Wafer size
A4 or 8 inch
Exposure area
230 mm(H) ×300 mm(V)
Exposure environment< 1 atm (He-gas)
III. BL03
BL03 is a beamline for the developing the next
generation lithographic technology so called extreme
ultraviolet lithography (EUVL). The exposure tool isinstalled at the end station. Using this exposure tool, theresearch and development of the next generation lithographysuch as the less than 70 nm node is going on process. The
exposure wavelength is 13.5 nm.
The semiconductor industry plays a very important rolein the information technology (IT). In 2006, 256 Gbit
DRAM with a gate length of 70 nm will be demanded in the
IT industry. The extreme ultraviolet lithography (EUVL) is
a promise technology for fabricating a fine pattern less than

70 nm. To meet this schedule, this technology has to be
developed in the pilot line until 2004. As for the practicaluse, it is very important that both to achieve large exposurearea and to fabricate fine patterns. Therefore, at HimejiInstitute of Technology, large exposure field EUV camera
consists of three aspherical mirrors was developed. First in
the world, we fabricated 60 nm line and space pattern in thelarge exposure area of 10 mm×10 mm on a wafer.
Furthermore, BL03B beamline branches from the BL03
beamline propose for the usage of the EUVL microscope for
the EUVL finished mask inspection. Table 4 shows the
specification of ETS-1.

Table 4. Specification of the exposure tool (ETS-1)
Imaging optics
Three aspherical mirrors
Exposure wavelength13.5 nm
Numerical aperture
0.1
Demagnification
1/5
Resolution
60 nm
Depth of focus
0.9 µmExposure area (static)
30 mm×1 mm
Exposure area (scanning)
30 mm×28 mm
Mask size
4 inch, 8 inch, and ULE 6025
Wafer size
8 inchExposure environment
In vacuum
IV. BL05
BL05 was constructed in response to a demand in theindustrial world, which is enhancement of the analysis
ability in the soft x-ray region with the development of
nanotechnology. BL05 consists of two branch lines for use
in the wide range from 50 eV to 4000 eV. BL05A and
BL05B are designed to cover the energy range of 1300-4000
eV and 50-1300 eV, respectively. The incident beam fromthe bending magnet is provided for two branch lines throughdifferent windows of a mask. Therefore, these two branchlines can be employed simultaneously. At the end stations ofeach branch, the transfer vessel systems were mounted forthe measurements of sample without exposure to air. In

addition, globe box was placed for the preparation ofsamples into transfer vessel.
1) The double crystal monochromator was installed at theBL05A. InSb, Ge, Si, SiO2, Beryl and KTP crystals areprepared for a double-crystal monochromator. Toroidal
mirrors are used as a pre-mirror and a focusing mirror of
BL05A. XAFS measurement in the total electron yield modeand fluorescence XAFS measurement using SSD (SII
Vortex) can be performed. The fluorescence XAFS spectra
can be measured for samples at the end station filled with
He gas. Table 5 shows the specification of monochromater.

5

Monochromator
Monochromator crystals
Energy range
Resolution

Table 5. Monochromator specification
Double crystal monochromator
SiO2（1010）, InSb（111）, Ge（111）, Beryl（1010）, KTP（110）, Si（111）1300-4000 eV
E/⊿E=3000
prepared at the end station of BL05B. The XAFS spectra in
the total electron yield mode and fluorescence XAFS spectrausing SDD (Ourstex) can be measured in a high vacuum
chamber. In addition, the photoelectron spectrum can bemeasured using spherical electron analyzer (VG Sienta,
R3000) in an ultrahigh-vacuum chamber. The chambers canbe replaced by each other within 1 hour. Table 6 shows the
specification of the monochromator.

2) The constant-deviation monochromator consisting of ademagnifying spherical mirror and a varied-line-spacing
plane grating (VLSPG), which can provide high resolution,
simple wavelength scanning with fixed slits, was mounted
on BL05B. The optical system consists of a first mirror (M0),a second mirror (M1), an entrance slit (S1), a pre-mirror(M2), and three kinds of plane grating (G), an exit slit (S2)and a focusing mirror (M3). The including angle of themonochromator is 175°. Two measurement chambers are
Monochromator
Grating
Energy range
Resolution

Table 6. Monochromator specification
Varied-line-spacing plane grating monochromator
100 l/mm, 300 l/mm, 800 mm/l
50-1300 eV
E/⊿E=3000

V. BL06
BL06 has been mainly developed for irradiation
experiments such as photochemical reaction, SR-CVD,
photo-etching, surface modification. The white radiation
beam from bending magnet is introduced to the sample stage
using a pair of mirror, whose incident angle was 3°. The
SR at BL06 sample stage had a continuous spectrum fromIR to soft x-ray, which was lower than 1 keV. A differential

pumping system can be utilized for experiments in a gas
atmosphere, which is difficult in the soft x-ray region. A
sample holder can install four pieces of samples at a time.
By using heater set in the sample holder, the sample can beheated from room temperature to 220C. The temperature ofsample is monitored using a Cr-Al thermocouple mounted
on the sample holder.

VI. BL07A and BL07B
This beamline was designed for the development of newmaterials by SR technology. This beamline consists of two
branch lines, which are provided with an incident beam froma 3-m-long undulator by switching the first mirror. One ofthem is a high photon-flux beamline with a multilayeredmirror monochromator for the study of SR-process (BL07A)
and another is a high-resolution beamline with a varied line
spacing grating monochromator for the evaluation of nanostructure characteristics by SR-spectroscopy (BL07B). The
useful range of emitted photons from 50 to 800 eV iscovered at both beamlines. The light source of BL07 is a 3m length planar undulator, which consists of 29 sets ofpermanent magnets, a period length of which is 76 mm. The
incident beam from the undulator is provided for two branchlines by translational switching of first mirror.
1) BL07A
The multilayered-mirror (MLM) monochromator, which
has high reflectivity in the soft X-ray region, was installedat the BL07A. It consists of a switching mirror chamber, aslit chamber, a MLM monochromator, a filter chamber anda reaction chamber. To obtain a large photon flux, we
decided to use only first mirror (switching mirror), M0, forfocusing. The MLM monochromator is designed to cover anenergy range of up to about 800 eV by combination of threekinds of mirror pairs with 4 kinds of filter. The flux deliverby this design is estimated to be between a maximum of 1017
photons/s at 95 eV and a minimum 21014 photons/s at 300
eV for a 500 mA ring current. Table 7 shows the summaryof BL07A. In addition, X-ray fluorescence (XRF) apparatus
using spherical varied line spacing grating was mounted at
the downstream of irradiation chamber. The poly capillary
was used to enhance beam-condensing efficiency.
Measurement energy range was from 30 eV to 450 eV. ThisXRF apparatus was expected to utilize the chemical analysis
on the light metals, Li and Be, and light elements, B, C andN.

6

Table 7. Summary of BL07A.
Multilayer mirror
spacing
Thickness number of
Ratio
layersEnergyrange(eV)Material

50-60
60-95

Mo/Si

90-140140-194

Mo/B4C

11 nm

0.5

25

3.3 %

190-400
400-560

Ni/C

5 nm

0.5

60

2.5 %

20 nm

0.8

20

550-800

E/E
6.2 %

Filtermaterial ThicknessAl
100 nmNone

Ag

100 nmCr

500 nmNi

500 nm(M2). The monochromator is designed to cover the energy
range 50-800 eV with three gratings, of which including
angle are 168. The VLSPG has been well known to obtainhigh resolution in extreme ultraviolet region by diminishingvarious kinds of aberration. The total resolving power about3000 can be realized in the whole energy region. Table 8shows the specification of the monochromator.

2) BL07B
The constant-deviation monochromator consisting of ademagnifying spherical mirror and varied line spacing planegrating (VLSPG), which can provide to high resolution,
simple wavelength scanning with fixed slits, was mounted
on BL07B. The optical system consists of a first mirror (M0),an entrance slit (S1), a premirror (M1), and three kinds ofplane grating (G), an exit slit (S2) and a focusing mirror

Table 8. Monochromator specification
Mount type
Hettrick-Underwood type
Grating G1, G2, G3
Plane VLS (600 l/mm, 1200 l/mm, 2400 l/mm)
Energy range
50-150 eV, 150 – 300 eV, 300-800 eVResolving power (E/ΔE)～3000
VII. BL09
A purpose of this beamline is studies on a soft x-ray
interferometry or a holographic exposure experiment withmaking use of highly brilliant and coherent photon beams
radiated from 11 m long undulator in NewSUBARU.
BL09 consists of M0 mirror, M1 mirror, G grating andM2 and M3 mirror. M0 and M3 mirrors are used forhorizontal deflection and beam convergence, M1 is used forvertical beam convergence at the exit slit, and M2 is used forvertical deflection and beam convergence. A
monochromator is constructed by M1 and a plane grating.
The maximum acceptance of the undulator beam is 0.64
mrad in horizontal and 0.27 mrad in vertical. The acceptancecan be restricted by 4-jaw slits equipped at upstream of theM0 mirror.
BL09A beamline is used for material analysis: X-ray

absorption spectroscopy (XAS) and X-ray photoelectron
spectroscopy (XPS). In 2013, X-ray emission spectrometer(XAS) was introduced at the endstation of the BL09A. Theenergy range and resolution of the XAS was designed to beabout 50-600 eV and 1500, respectively.
BL09B beamline branched from BL09 beamline for theusage of the EUV interference lithography for the evaluationof the exposure characteristics of EUV resist. Coherence
length of 1 mm at the resist exposure position was achieved
using BL09B beamilne. And BL09C beamline branchedfrom BL09B beamline for the usage of the thickness
measurement of the carbon contamination originated to theresist outgassing during the EUV exposure. Table 9 shows
the specification of the monochromator.

Table 9. Monochromator specification
Mount typeMonk-Gillieson type
Grating
Plane VLS (300, 900, 1200 l/mm)
Energy range
50 – 750 eVResolving power (E/ΔE)
～3000

7

VIII. BL10
BL10 is for the global use in the Himeji Institute ofTechnology. M0 mirror is used for horizontal deflection andbeam convergence, M1 is used for vertical beam
convergence at the exit slit, and M2 is used for verticaldeflection and beam convergence. A monochromator isconstructed by M1 and a plane grating. At the beginning, themultiplayers reflectivity measurement was carried out at thisbeamline. The characteristics of this beamline and the resultof the Mo/Si multiplayers measurement are carried out forthe development of the EUV- mask technology.
BL10 utilizes a monochromator of the varied line spacing
plane grating monochromator (VLS-PGM). The line densityof the monochromator in central region of the gratings were
600, 1800 and 2,400 lines/mm. The reflectometer is a two
axis vacuum goniometer using two Huber goniometers. One
axis carries the sample, which may for examplee be a mirror
at the center of the reflectometer vacuum tank (-motion).
The other (-motion) carries the detector on a rotating arm.

In addition there are through-vacuum linear motions totranslate the sample in two orthogonal directions (x,y). All
motors are controlled by computer. The sample itself ismounted on a kinematic holder. The control stage
monochromator rotation, and data analysis were programusing LABVIEW software. The reflectivity result obtainedat BL10 has a good agreement with that at LBNL. Table 10shows the specification the monochromator.
The micro-CSM tool was adapted at the most downstreamof the BL10 beamline for the EUV mask defect inspection.
This too is very effective for the inspection of the actinic
patterned mask.
A large reflectometer was installed in a branch line for large
EUV optical component including EUV collector mirrors.
The reflectometer has a sample stage with y, z, , , and Tilt
axis, which can hold large optical elements with a maximum
weight of 50 kg, a diameter of up to 800 mm, and a thicknessof 250 mm. The entire sample surface is able to be measured.

Table 10. Monochromator specification
Mount type
Hettrick-Underwood type
Grating
Plane VLS (600, 1800, 2400 l/mm)
Energy range
50 – 1,000 eVResolving power (E/ΔE)～1000

IX. BL11
A beam line BL11 is constructed for exposure Hard Xray Lithography (DXL) in the LIGA (German acronym for
Lithographite Galvanoformung and Abformung) process.
LIGA process, that utilizes a useful industrial application of
SR, is one of the promising technologies for fabrication of
extremely tall three-dimensional (3D) microstructures witha large aspect ratio. This process was invented at the Institut
Fur Mikrostrukturtechnik (IMT) of the Karlstuhe Nuclear
Center (KfK) in 1980. Microstructures with height of overa few hundreds µm have been widely applied to various
fields such as micro-mechanics, micro-optics, sensor andactuator technology, chemical, medical and biologicalengineering, and so on. This beam line was designed by thecriteria ; photon energy range from 2 keV to 8 keV, and adensity of total irradiated photons  1011 photons/cm2. The
BL11 can provide the most suitable photon energy for
microfabrication in X-ray lithography, while the BL2 isequipped for fabricating fine pattern submicron-scale
structure and microstructure with high aspect ratio byselectivity of X-rays using movable mirror system. That is,
LIGA process in NewSUBARU can provide the best 3D
microfabrication because the BL11 and BL2 arecomplementary. The beamline BL11 is consisting of anabsorber chamber, a first-mirror chamber (M1), a 4-way slit
chamber, a Be and polyimide window chamber, and an
exposure chamber. The horizontal angle of the outgoing SR
could be obtained up to 17.8 mrad, providing a beam spot
size on the exposure stage  80  mm2. The micron-scale
structure with high aspect ratio will be achieved using thetoroidal typed mirror M1 which can produce a parallel
collimated beam of X-rays. In addition, the homogeneity ofthe beam is excellently controlled by a novel adding system.
Using the precision stage in the exposure chamber, theflexibility for the shaped and functions of microstructure
will be enlarged by achieving 3D microfabrication processusing multi step exposure at various configuration between
x-ray mask and substrates. The exposure area of 200 mm
ൈ 200 mm is brought to fruition. In order to decrease the8heat load of sample substrate suffered during SR irradiation,
helium introduction and substrate cooling system were also

equipped. The specification of the LIGA exposure system
is listed in Table 11.

Table 11. Specification of the LIGA exposure system
Exposure method
Proximity exposure
Wafer size
8 inch200 mm(H)×200 mm(V)
Exposure area
Exposure environment< 1atm (He-gas)

Acknowledgement
We would like to thank all the staff who work at
NewSUBARU synchrotron light facility for their help
to describe the update details of the beamlines.

9Recent Improvements on the Beam Operation of the
NewSUBARU Electron Storage Ring
S. Hashimoto, Y. Takemura#, H. Takeuchi#, K. Morisato# and S. Miyamoto
LASTI, #JASRI

Abstract
Recent improvements on the operation of NewSUBARU electron storage ring are reported. The
stored energy is stably ramped from 1.0 to 1.5 GeV without any beam loss. The minimum gap of
the long undulator becomes under 30 mm.
Introduction
Recent synchrotron radiation users at the
NewSUBARU facility [1] desire the higher
brightness, the higher stability of synchrotron
radiation, and the operation at narrower gap ofinsertion devices. In order to respond to theserequests, we have performed machine studies.
In this paper we report recent
improvements on the beam operation of
the NewSUBARU ring including (1) thestable energy ramping, (2) the shorteningof the time for the energy ramping, and (3)the operation with 10.8m-long undulator
with a gap narrower than before.

Fig,1 Beam energy and current during the energy
ramp

Stabilization of 1.5GeV energy ramping
Electron beams are injected at theenergy of 1.0 GeV from the SPring-8 Linac.
In the case of 1.5 GeV, the stored energy isramped up.
The former ramping
parameter sometimes caused beam loss
during the energy ramping because ofannual drifts of temperatures, beam
instabilities and so on.
Thus were-adjusted the new ramping parameter
including fine-tuning of quadrupole,
sextupole and stearing magnets at theeach energies.
By using the newparameter, the beam loss or thedeterioration of the beam lifetime hardly
occurs. Fig.1 shows typical variation of
the stored beam current and energy
during the energy ramping.
Our ring usually stops an operation atnight. Every morning, electromagnets are
initialized after power-on. By optimizing
and automating the operation procedure forstable energy ramping, the time required until
the start of the 1.5 GeV user experimentbecomes shorter than before.

Operation with narrower gap of 10.8m-longundulator (LU)
The gap length is narrower, the effectsof the nonlinear magnetic field of
insertion devices on the electron beams isstronger.
For compensation of these
disturbances, the strength of several
kinds of magnets is adjusted according to
the gap length.
The minimum gap
length that can be realized in the previous
was 34.8 mm.
Recently some users
requests lower energy range of LU. Aftermachine studies, the present minimum
gap becomes 26mm at 1.5 GeV operation.
This is almost same as the physicallypossible minimum value. At the energyof 1.0 GeV, injection efficiency issomewhat lower (~50%) than the required
value 80% at the top-up operation.
Further tunings of sextupole and skew
quadrupole magnets are being performed
toward the realization of the top-up
operation with LU gap 26mm at 1.0GeV.
References[1] http://www.lasti.u-hyogo.ac.jp/NS-en/

10

Simulation Study on Optimization of the Beam Dynamics
at LEENA Accelerator
Satoshi Hashimoto, Karin Kobayashi, and Shuji Miyamoto
LASTI

Abstract
By simulation, we studied the beam dynamics of the 15MeV electron linear accelerator LEENA
and calculated the optimized parameters for short bunching of electron beams to generate the highpower coherent radiation in the terahertz region.
Introduction
We have been researching thegeneration of the terahertz light using
relativistic electron beams of the 15MeV
electron linear accelerator LEENA [1].
The general layout of LEENA is shown in
Fig.1.
The terahertz lights bysynchrotron radiation (SR), Smith-Purcell
radiation, and transition radiation havebeen successfully observed [2].
Fig.2 Intensity of coherent and incoherent
synchrotron radiation from a bending magnet of
LEENA (calculation). Bunch lengths are 1,
10 , 30 ps.
Forming electron bunches in the RF-gun
Electrons are continuously supplied
from a thermal LaB6 cathode and areaccelerated by the RF electric field in the
gun cavity (Fig.3). RF frequency is 2856
MHz.

Fig.1 General layout of LEENA.
The intensity spectrum of the SR lightfrom a bending magnet of LEENA isshown in Fig. 2, where Coherent SR (CSR)
is plotted in addition to “usual” SR. The
CSR is generated from an electron bunch
shorter than the radiation wavelength.
The radiated power of CSR is proportional
to the square of the number of electron N
in a bunch and is N-times higher than“usual” SR.
In this paper, an electron beam dynamics at
RF-gun, solenoid coil, alpha magnet is
calculated using simulation codes and the
optimum parameters for the short bunching to
generate the CSR in terahertz region are shown.

Fig. 3 Electric fields in the axially symmetricRF-gun cavity of LEENA calculated withSUPERFISH [3]Electrons in the accelerating phase of the RF
field are drawn out from the cathode. Whilethese electrons travel through a drift space, thevelocity modulation is converted to the density

11

modulation and electron bunches are formed.
The electron number distribution calculatedusing GPT [4], 3D particle tracking code withspace charge, is shown in Fig.4.
Fig.5 shows the energy (Lorentz factor) ofelectrons. The energy is almost linear withrespect to the direction of travel and the gradientof three bunches are 15, 11, 9.4 MeV/m fromleft to right. As the drift space is longer, theenergy gradient becomes gentle.

Fig.6 Time evolution of radial distribution ofelectrons without solenoid field.

Fig.4 Electron number distribution along thelongitudinal direction z after three periods ofRF.

Fig.5 Electron energy (Lorentz factor)
distribution along z after three periods of RF.

Fig.7 Time evolution of radial distribution ofelectrons with solenoid field.

Focusing electron beams by the solenoid coil
An electron beam diverges in radial
direction due to its space charge effect.
To compensate this, the water-cooledsolenoid coil (300 A, 75 turn, 0.37 Tesla) is
placed in about 40cm downstream of thecathode.
Fig. 6 shows the time evolution of electron
radial distributions in the case of no solenoid
field, where the radius of bunched beams isdiverged. When a solenoid coil current is set
to the optimum value that depends on the beam
current, beams are well focused as shown in Fig.
7. Fig. 8 shows the solenoid coil current
dependence of calculated beam profiles at theentrance of the alpha magnet. This result
qualitatively agrees to the experimental results
measured by the screen monitor placed at theentrance of alpha magnet.

Fig.8 Calculated electron beam profile at theentrance of the alpha magnet when the solenoid
coil current is varied.
Bunching in Alpha magnet
In an alpha magnet, electron trajectoryis like the Greek letter alpha, where thefaster (slower) electron passes through theouter (inner) trajectory. As a result, atthe exit of the alpha magnet, a bunch
length is shortened. Cross-sectional viewof the upper half of the alpha magnet andthe magnetic lines of force calculatedusing POISSON [3] are shown in Fig. 9. 	
 12bunch length of 30 ps at the entrance of
the alpha magnet, the shortest bunch
length at the entrance of the linear
accelerating
tube
that
is
0.39m
downstream to the alpha magnet is foundto be 2 ~ 3 ps.
This bunch length
corresponds to a wavelength in terahertz
region.
In order to realize the above condition, therequired energy gradient at the entrance of thealpha magnet is 20 MeV/m. However, as
shown in Fig. 5, the typical energy gradient isless than 10 MeV/m and is insufficient forachieving the shortest bunch length.
Three solutions to this problem can beconsidered; (1) increase the RF power
introduced to the RF gun to steep the energy
gradient, or (2) shorten the distance between the
RF gun and the alpha magnet, and (3) shorten
the distance between the alpha magnet and theaccelerating tube. It is effective to shorten thedrift space in order to prevent the bunch lengthis extended. We are now preparing to modify
the experimental setup.

Fig.9 The cross-sectional view of the upper
half of the alpha magnet and its magnetic lines
of force.

Summary
For the generation of the high powerradiation in terahertz using relativistic
electrons, the bunch length of an electron
beam should be under about a few ps. By
simulation studies, we calculated andvisualized the beam dynamics at the RFgun, solenoid and alpha magnets of
LEENA.
As a simulation result, it is found thatthe minimum bunch length that can be
possible at LEENA is about 2 ps. But
some modifications of devices may berequired for achieving it. We are now
consideringandpreparingthemodification of the machine.
References[1]http://www.lasti.u-hyogo.ac.jp/NS-en/facility/leena/[2] LASTI Annual Report, Special Issue: The
20th Anniversary vol.16, ISSN 2189-6909(2014), in Japanese[3] POISSON/SUPERFISH codes,	 http://laacg.lanl.gov/laacg/services/download_sf.pht
ml[4] GPT, http://www.pulsar.nl/gpt/index.html

Fig.10 Bunching process of an electron beamin the alpha magnet calculated using GPT.
The particle tracking calculation with
3D space charge effects in the alphamagnet is carried out, where magnetic
field data is converted from POISSON to
GPT format. The bunching process isshown in Fig. 10. Using the typical13

High average power soft X-ray in the water window fromAr laser plasma
Sho Amano
LASTI/ UH

Abstract
High average power of 140 mW and high conversion efficiency of 14% were demonstrated in“water window” soft X-rays generated by a laser plasma source that was developed in-house,
when a commercial Nd:YAG Q-switched laser was used to irradiate a solid Ar target with energyof 1 J at a repetition rate of 1 Hz. The source has a translating substrate system with a cryostat thatcan continuously supply the solid Ar target for repetitive laser pulses, and continuous and stable
output power is achieved from the Ar plasma emission.
Introduction
Soft X-rays (SXRs) in the “water window”
region between the K absorption edges ofoxygen at 2.3 nm and carbon at 4.4 nm are used
for high contrast SXR microscope imaging
studies of live biological samples because of thedifferent absorption lengths of water and theproteins in biological specimens. We considered
the development of a continuous laser plasma
X-ray (LPX) source in the water window using
a solid Ar plasma target. Ar is considered tobe ideal deposition-free targets because it isformed from inert gas rather than metals, andwill thus be chemically inactive and will not be
deposited on the mirrors near the plasma. This
reduction in plasma debris is a major advantage
in continuous operation. We decided to use acryogenic Ar solid target to provide both higher
conversion efficiency and higher brightness
because of the target’s high solid density. In
addition, a smaller gas load for evacuation by
the exhaust pump system was expected from thesolid state target when compared with gas andliquid jets. We originally developed a cryogenictranslating target system to supply the solid Ar
target continuously. Using this system, we
successfully produced a continuous supply of Ar
solid targets and demonstrated the continuous
generation of LPX emissions at repetition rates
of up to 10 Hz produced by a commercial
Nd:YAG Q-switched rod laser. In this paper, we
report the plasma SXR emission characteristics
in the water window of a solid Ar plasma target
supplied by the developed system [1].

cooled to a temperature of 15 K. The Ar target gas isblown on to the substrate surface and is thus
condensed to form a solid layer. The substrate thatwas coated with the solid Ar layer translates up anddown, with movement in only one dimension, whichmeans that a fresh target surface is supplied for eachlaser shot. In this experiment, the Ar gas flow rate andthe target speed were set to be 250 mL/min and either
3 or 4 mm/s, respectively. Wipers are used to adjust
the Ar solid layer thickness to 500 µm, which is
sufficient to prevent a 1 J laser shot from damaging
the substrate surface, and these wipers also assist in
re-covering the laser craters on the target. The entire
vacuum chamber was evacuated using a 190 l/s turbo
molecular pump, and the vacuum is maintained at lessthan 1 Pa.

Fig.1. Side view of the LPX source, including the translating
cryogenic target system.

Experiments
Figure 1 shows the side view of the developed
LPX source, including the system used for continuous
supply of the cryogenic targets. The target system is
described in detail in [2]. A copper substrate was
attached to the tip of a cryostat head with a He gas
closed loop, enabling the substrate surface to be

A conventional Q-switched Nd:YAG rod laser(Spectra-Physics, PRO-230) was used as a pumpsource and could deliver pulses at a wavelength of 1ω
(1064 nm) with a pulse width of 10 ns. The maximum
pulse energy and the repetition rate are 1.2 J and 10
Hz, respectively. The pulses were expanded using a

14

beam expander before passing through a window, andwere then focused perpendicularly on the target via alens with a focal length of 500 mm; as a result,plasmas were produced and SXR radiations were
emitted.

1 J×1 Hz×14%) in the water window (2.3–4.4 nm).
We expect our LPX source to offer a powerfulalternative to the use of SR facilities for thedevelopment of various applications, including SXR
microscopy.

Results & Discussion
To measure the generated SXR energy, anabsolutely calibrated X-ray diode (XRD) with 200 nm
titanium and 50 nm carbon filters (Opto Diode,AXUV100Ti/C2) was used. The XRD’s specifications
state that it has a detection range of 1–12 nm. By
measuring the SXRs using the XRD located at 45° tothe axis of laser beam incidence, we were able tooptimize the operating conditions in terms of laser
intensity and energy to maximize the CE. By changing
the position of the focusing lens to vary the laser spot,
the laser intensity on the target could be adjusted todetermine the optimum intensity. Figure 2(a) shows
the CE per unit solid angle as a function of the lensposition (laser intensity). The laser pulse energy used
was 0.5 J at 1 Hz. We denote the lens position (LP)using a zero at the best focus position, a negative
number when in-focus (where the laser spot is in thetarget before the best focus) and a positive number forout-of-focus (beyond the best focus). Figure 2(a)shows the maximum CE at the best focus of LP = 0mm, at which the laser spot diameter was 50 µm. Next,
the lens position was fixed at LP = 0 mm and thedependences of the laser pulse energy were
investigated. Figure 2(b) shows the CE per unit solid
angle as a function of the laser energy. This indicatesthat the CE was maximized at a laser energy of 1 J.
From the above results, we concluded that the
maximum CE per unit solid angle was achieved at LP= 0 mm and at a laser energy of 1 J, and the laser
intensity was estimated to be 5×1012 W/cm2.
The spatial distributions of the SXR emissions
were measured by scanning the XRD on a rotatingstage around the plasma. The measurements showedthat these distributions could be expressed using afitting curve of (cosθ)0.41. Taking this distribution into
account, we obtained a maximum spatially integrated
CE of 19% over the full XRD detection range (1–12nm). With regard to the CE in the “water window”
region, it can be calculated from the ratio of the areain the water window to the full range of the Ar
spectrum shape. This ratio was calculated to be 0.76
and we concluded that the maximum spatiallyintegrated CE was 14% in the water window (2.3–4.4nm) with a laser energy of 1 J.
We then tested for repetitive generation of theplasma SXR pulses by focusing laser pulses withenergy of 1 J at 1 Hz on the Ar target surface. The
combination of the Ar gas flow rate and the target
speed enable a re-covered target surface to be supplied
for each laser pulse. The continuously generated
repetitive SXR pulses were obtained successfully. In
this experiment, we achieved continuous SXR
generation with a high average power of 140 mW ( =15

Fig.2. (a) CE per solid angle in full detection range (1–12nm) as a function of lens position (LP). The laser energy
was 0.5 J. (b) CE per solid angle at LP = 0 mm as a functionof laser energy.

Acknowledgments
This work was supported by JSPS KAKENHI (Grant
No. 23654204 & 26390113) and Hyogo Science andTechnology Association (Grant No.26049).

References[1] S. Amano, Appl. Phys. Exp. 9, 076201(2016).
[2] S. Amano, Rev. Sci. Instrum. 85, 063104(2014).

Present Status of BL05A Performance
T. Hasegawa1, 4, S. Fukushima2, 4, T. Kotaka3 and K. Kanda4
1 Synchrotron Analysis L.L.C., 3-2-24 Wadamiya-dori, Hyogo-ku, Kobe-shi, Hyogo 652-0863 Japan
2 National Institute for Materials Science, 1-2-1 Sengen, Tsukuba-shi, Ibaraki 305-0047 Japan
3 New SUBARU, 1-1-2, Koto, Kamigori-cho, Ako-gun, Hyogo 678-1205 Japan
4 LASTI, University of Hyogo, 3-1-2 Koto Kamigori-cho, Ako-gun, Hyogo 678-1205 Japan

Abstract

A renewed double crystal monochromator (DCM) improved performance of BL05A for X-ray
absorption fine structure (XAFS) measurements in the soft X-ray region. We were successful inobtaining the extended X-ray absorption fine structure (EXAFS) spectrum owing to the stability ofthe exit X-ray beam intensity of the new DCM. In addition, we succeeded to obtain thealuminium K-edge X-ray absorption near edge structure (XANES) spectra because of theincreased photon intensity in the aluminium K-edge region by replacing the beryllium filter (45m thickness) with previous one (25 m thickness).

Introduction
BL05 is constructed on the basis of strong
demand of industrial users for X-ray absorption
fine structure (XAFS) spectroscopy. This
beamline consists of two branch lines, one is adouble crystal monochromator (DCM) beamline(BL05A) for the use in the higher-energy region(1300-4000 eV) and the other is a varied line
spacing plane grating (VLSPG) monochromator
beamline (BL05B) for the use in thelower-energy region (50-1300 eV) [1, 2]. Anangle that accepts X-rays exiting from thestorage ring is different in BL05A and BL05B
respectively, and so these branches can be
operated simultaneously. BL05 is managed andmaintained by the Synchrotron Analysis L.L.C.
(SALLC), which is composed of the industrial
companies, in cooperation with the staffs of theLaboratory of Advanced Science andTechnology for Industry in University of Hyogo.
We replaced the DCM in BL05A tocorresponding to the user’s demands forhigh-precision EXAFS measurements. In thispaper, we describe improved performance of
BL05A for XAFS measurements in the soft
x-ray region.

translating system of the crystals on the DCM.
Therefore, It was difficult for the extended
X-ray absorption fine structure (EXAFS)
measurement, such as the bragg angle wasvaried widely, due to excessive attenuation of
the monochromatic exit beam intensity. And soarenewedDCM,
calculation
andcombination-type, was installed in 2014 (Fig.1).
This new DCM is designed to maintain a goodparallelism between crystals and stability ofthe exit X-ray beam position when scanningover a large energy range by moving all axes ofcrystals controlled by computer. Fig.2 shows themeasured silicon K-edge EXAFS spectra ofsilicon dioxide (-quartz) using the previous
DCM and the new one, respectively. We foundout that high-quality EXAFS spectrum was
obtained in the new DCM.

1. EXAFS measurements using a renewed
double crystal monochromator
In BL05A, a Golovchenco-type DCM has
been used from 2008, the operation for public
use of BL05 has started. The stability of the
DCM is the most important factor in beamline
performance. The DCM is mounted two parallel
crystals to each other to produce a
monochromatic exit beam which is runningparallel with the incident white synchrotron
radiation beam. But there was a problem withstability of the exit X-ray beam intensity, caused
by deterioration of a driving mechanicalFig.1 Inside of a renewed DCM.
2. Evaluation of a improved beryllium filter
In the soft X-ray beamlines, a beryllium
filter is often used to protect the vacuum within16the storage ring from contamination because ofproviding a vacuum isolation and transmitting
the X-ray beam. The beryllium filter in BL05A
is installed to separate the ultra-high vacuum inthe storage ring with the front-end from the highvacuum in the beamline, which is bonded tomounting flange. For the purpose of improving
the transmission factor of X-rays at thelower-energy region (e.g., the K absorption
edges of elements with atomic numbers lessthan silicon), we succeeded to make the filter ofthicknesss from 45 m down to 25 m andobtain the magnesium K-edge XANES spectrain the past [3]. Then we tried to measure thealuminium K-edge XANES spectrum using the
new filter. In Fig.3, the measured aluminium
K-edge XANES spectra of several aluminium
compounds are shown. We verified that there isenough photon intensity in these lower-energy
region and can be obtained high-precision
XANES spectra, which provide a detailed
information related to chemical bond.

Normalized intensity（a.u.）

Al plate

1570

1580

1590

1600

Photon energy（eV）

Fig.3 Al K-edge XANES spectra ofaluminium compounds.
References[1] T. Hasegawa et al., Advances in X-ray Chem.
Anal. Jpn., 41, pp.99-106 (2010) [in Japanese].
[2] K. Kanda et al., J. Phys.: Conf. Ser., 425,
132005/1-4 (2013).
[3] T. Hasegawa et al., LASTI Annual Report,
vol.16, pp.73-74 (2014).

Intensity（a.u.）

2000

2200

2000

2200

Photon energy（eV）

Intensity（a.u.）

(b)

1800

AlN powder

1560

(a)

1800

-Al 2O3 powder

Photon energy（eV）

Fig.2 Si K-edge EXAFS spectra of silicon dioxide(-quartz) powder, (a) Golovchenco-type DCM and(b) calculation and combination-type DCM.

17

Development of the control system of double multilayers
monochromator in New SUBARU BL07A
Masato Okui1 2, Isao Kikuchi2, Naoki Yato2, Akinobu Watanabe2, Norio Murayama2,
Sei Fukushima1 3 and Kazuhiro Kanda3
1LASTI, University of Hyogo, 2Kohzu Precision Co., Ltd.,and 3National Institute of Material Sciences
E-mail: okui@kohzu.co.jp

Abstract
The upgrade project of New SUBARU BL07A began on 2013. In this project, a new double multilayers
monochromator MKZ-7NS controlled by integrated computing was installed on the beamline. The featuresof the monochromator are shown from the point of view of the optical geometry in this report. A new control
system using electronic cam algorithm on PC software was introduced since 2016 Spring. The software inthis control system could scan with wave length continuously that was conventionally thought to be difficult
using a computing type monochromator.
Introduction
It is clear that a double crystal / multilayers
monochromator plays an important role in many
experiments using synchrotron radiation. The
following two types of monochromator have been
adopted widely in order to keep the fixed beam
position on their downstream experimental
equipment. One is a cam-actuated monochromatorthat the slave axes are connected mechanically to themain axis e.g. [1], and the other is a monochromator
controlled each mechanically independent axes bycomputing e.g. [2].
BL07 in New SUBARU is a beamline whose an
insertion light source is a 3m undulator. This
beamline is composed of two branch lines BL07A
and BL07B [3]. The upgrade project of this beamline
began on 2013. In this project, a new double
multilayers monochromator Kohzu MKZ-7NS
controlled by integrated computing was installed on
BL07A [4].
In this report, the authors shall describe thefeatures of the this new monochromator, MKZ-7NS.
Additionally, they shall describe our new control
system using electronic cam algorithm on the control
software. The software in this control system shallbe able to scan with wave length continuously thatwas conventionally thought to be difficult using thecomputing type monochromator.

outside of the vacuum chamber. Thus, numbers ofaxes inside of the vacuum chamber are decreased to
5 axes less than the previous monochromator [2].

(a)

(b)

Fig. 1. Photograph of MKZ-7NS,(a) MKZ-7NS on BL07A in New SUBARU;(b) Inside of the Monochromator

Fig. 2. Outline drawing of MKZ-7S
monochromator

The feature of MKZ-7NS
Fig. 1 shows the photograph of MKZ-7NS and its
inside of their chamber. Fig.2 shows outline drawingof MKZ-7NS. The optical geometry using offset
along the optical axis direction of the second
monochromatic multilayers was adopted in MKZ7NS as with the geometry of Kohzu KHL-3 in KEK
PF [5]. A slave axis synchronized with main axis foremitting to fixed exit position is only Z2 axis. X axis
used for switching of monochromatic crystals is

New control system for MKZ-7NS
Motor controllers, motor drivers and their control
software was included in this control system. This
motor controller was customized on the basis ofKohzu ARIES/LYNX multi-axis controller. The
customized controller is able to change arbitrarily
target position and speed during driving a motor
without stopping movement. The optional function

18

Experimental results
New control software with electronic cam
algorithm was installed to Windows PC that has
been used for controlling its monochromator in
BL07A. Since 2016 Spring, some verification
experiments was performed in this beamline.
Z2calc that is calculated Z2 position by equation(1) and Z2act that is actual position controlled by thiselectronic cam control algorithm are shown in Fig. 5
with regards to θ angle, respectively. In Fig. 5, thedifference between calculated position and actual
position is also shown as ⊿Z2, together.
In this experiment, 130eV was used as photon
energy from its undulator in this experiment. And themain axis theta was driven from 14.6661deg to20.7469deg.

of this controller make an electronic cam on thefollowing control system practicable. The opticalgeometry is shown as Fig. 3 [4].

Fig. 3. Opticalmonochromatorgeometryof

MKZ-7NSZ2 position of the slave axis synchronized tomain axis is expressed by the following equation (1),where D is the offset of the monochromatic crystals,
θ is the Bragg angle, and D0 is the distance of themonochromatic crystals when the Bragg angle is theorigin [4].
𝐷𝐷Z2 =− 𝐷𝐷0 (1)
2 cos 𝜃𝜃

Electronic Cam
The series of function of electronic cam shall be
provided by the control software that remotecontrols the motor controller on Windows PC. The
flow chart of the algorithm of the electronic cam
used in the control software is shown in Fig. 4. In
this algorithm, the Y2 position is always corrected
automatically to new position that is calculated byequation (1) each time when the control software
gets newly the main axis position without stopping
their movement even if the slave axis is moving.

Fig. 5 Z2 position regards to θ angle and thedifference between Z2act-Z2calc, ⊿Z2

In Fig. 5 the line of actual Z2 position controlled
by the algorithm of the electronic cam would bealmost similar to it of calculated ideal Z2 position.
The maximum difference between the calculated Z2
and the actual Z2 is approximately 1.1μm.
This result shows the electronic cam algorithm
would be able to provide permissible fixed exit
position of monochromatized radiation from themonochromator for almost user experiment in
BL07A.
This electronic cam algorithm shall be able toscan with wave length continuously by a computing
type monochromator as well as a mechanical camactuated type monochromator.
References[1] M. Yabashi et al. Proc SPIE, 3773, pp.2-13,(1999).
[2] A. Nisawa et al. Nucl. Inst. & Meth. In Phys.
Res. A, 497, pp.563–568 (2003).
[3] K. Kanda et al. Nucl. Inst. & Meth. In Phys.
Res. A, 467–468, pp.500–503 (2001).
[4] M. Okui et al., AIP Conf. Proc., in press.
[5] H. Kawada et al., AIP Conf. Proc., 705,
pp.663–666 (2004).

Fig. 4 Flow chart of electronic cam

19Performance of BL07A installed new multilayered-mirror
monochromator
Shotaro TANAKA1, Naoki YATO2, Masato OKUI1, 2, Sei FUKUSHIMA1, 3 and Kazuhiro KANDA1
1. LASTI, University of Hyogo
2. Kohzu Precision Co., Ltd.
3. National Institute for Materials Science.
Abstract
New integrated computing mulutilayered-mirror monochromator (MLMM) was installed at BL07A
to eliminate unnecessary harmonic light from an undulator. BL07A is 3-m undulator beamline forhigh photon-flux irradiation with monochromatized light. These characters satisfy for SR
stimulation process experiments such as single excitation process experiments and low temperatureprocess. We measured intensity at irradiation chamber using photodiode. As a result intensity ofincident beam was more than 1014 photons/s･cm2 at the energy range of 80-560 eV at irradiationchamber of BL07A.

Introduction
New MLMM was installed at BL07A. BL07A is
3-m undulator beamline. It is designed for highphoton-flux irradiation. Energy of incident light canbe selected because of quasi-monochromalized
light. But unnecessary harmonic light is also
irradiated, and it becomes hard to study single
excitation process.
Recently, single excitation process experiments
are required. For example, Si crystallization at low
temperature is utilized for flexible display andmolecular knife can be studied for modification ofmaterials. For experiments of single excitation
process, integrated computing multilayerd-mirror
monochromator (MLMM) was installed at BL07A.
In soft X-ray region, the reflectance of many
materials is very small. However energy resolution
is high, intensity used normal double crystal
monochromator is decreased. Multilayered mirror isfitted for improvement of reflectivity index in soft
X-ray region. Incident light is reflected by many
interfaces on multilayered mirror, and there areinterfered. Thus, higher reflectance can be gainedusing multilayered mirror. Therefore, multilayered
mirror was selected as monochromatic devices
instead of crystal.
In this report, the intensity of incident beam at
irradiation chamber of BL07A was measured using
photodiode.

Multilayered mirror
Monochromator, MKZ-7NS designed andfabricated by Kohzu Precision Co. Ltd wasconstructed at BL07A [1]. MKZ-7NS is controlled
by integrated computing. The Bragg angle can befrom 9° to 65°. Detailed information on MKZ7NS was reported on ref. [2].
Table 1.Multilayer mirrors.

Energy (eV)80-200125-360
260-800

multilayer
Mo/Si
Mo/B 4C
Ni/C

Spacing
20 nm
11 nm
5 nm

Three kinds of multilayered mirror were used forcovering an energy range from 80 to 800 eV. Table
1 shows used multilayered mirrors. Howeverreflection of multilayered mirror is higher,
harmonic light is also occurred. For elimination ofharmonic light from multilayered mirror, threekinds of filter were mounted. Table 2 shows detail
Table 2. Filers.

Energy (eV)140-400
400-560
560-800

FilterAg
Cr
Ni

Thickness
100 nm
500 nm
500 nmof filters. Combinations of mirrors and filters could
be realized high intensity monochromatized light.

20

Conclusion
The intensity of incident beam at irradiationchamber of BL07A was measured using photodiode.
As a result, the intensity was more than 1014
phtons/s･cm2 at the range from 80-560 eV. Thisintensity can be used for irradiation experiments
sufficiently, and ionized energy of useful lightelements, such as C, Si was covered.

The intensity of incident beam at irradiationchamber of BL07A was measured by a photodiode(AXUV-100). Light reception area of thisphotodiode was 1 cm2. Intensity unit was defined
photons/s･cm2.
Result and discussion
Figure 1 shows intensity of incident beam at
irradiation chamber of BL07A. During thisexperiment, the electron energy of NewSUBARU
storage ring was 1.0 GeV. In the energy range of 80200 eV, maximum of intensity was more than 1015
photons/s･cm2, and in the energy range from 200560 eV, maximum of intensity was more than 1014
photons/s ･ cm2. This intensity can be used forirradiation experiments sufficiently. But, in theenergy range of up to 800 eV, the intensity was
drastically decrease. This is considered the intensityof monochromatized light is cut by Ni filter. 7th
harmonic light was the highest intensity at the rangeof 200-560 eV. But 7th harmonic light was not
ensured monochromatized condition. Therefore,
when this beamline was used, 1st-5th harmoniclights should be used.

2

photons(photons/s·cm )

1016

10

15

10

Ring Energy=1.0 GeV Ring Current=300 mA
3rd
5th,7th3rd,5th
7th

1st

1014

13

Reference[1] K. Kanda et al., Nucl. Inst. Meth. A, 467-468(2001)500.
[2] M. Okui et al., Proc. SRI2015, (2015).

7th
5th

3rd

Multilayer Filter
Mo/Si none
Mo/Si Ag
Mo/B4C none
Mo/B4C Ag
Ni/C
Ag
Ni/C
Cr
Ni/C
Ni

7th

7th
5th
7th
5th

5th

3rd

3rd

7th
1012

200

400

Energy /eV

600

800

Figure 1. Intensity of incident beam at irradiation chamber at 1.0 GeV operation mode.

21

Adjustment of the equipment for the measurementof Ultra-soft X-ray Fluorescence Spectrum on BL07A
Sei Fukushima1,2, Hiroki Takamatsu1, Shotaro Tanaka1, Kazuhiro Kanda1
1: LASTI, University of Hyogo, 3-1-2 Koto Kamigori-cho, Ako-gun, Hyogo 678-1205 Japan
2: National Institute for Materials Science, 1-2-1 Sengen, Tsukuba-shi, Ibaraki 305-0047 Japan

Abstract
For the development and investigation of ultra-soft X-ray fluorescence spectroscopy for the
non-destructive chemical state analysis of ultra-light elements in several advances materials, theequipment with high-performance type spectrometer had been installed at the end of BL07A in
2014FY. However, the existence of some items on which countermeasures should be required was
revealed in last FY. In this report, tow of countermeasures is presented.
Introduction
For analyzing the chemical state or
the electronic structure of valence band,
one of the most popular methods is XAFS
(X-rayabsorption
finestructure)measurement, and NewSUBARU has
been already executed and obtained
many remarkable results in the field of
ultra-light elements such as Li, C and soon. However, one of the disadvantage
points of XAFS measurement is thenecessity of sweep the energy of incident
X-rays. As known well, the efficiency of
excitation for core level of such ultra-lightelement is so low, thus highly condensed

monochromatized X-ray beam with highphoton flux should be necessary formeasurement.
In contrast, the energy sweep ofincident X-rays are not necessary for
obtaining
any
fluorescent
X-rays(characteristic X-rays) from the samples.
Thus, the examination about thepossibility of application of fluorescent
X-rays of ultra-light elements isimportant as a practical meaning.
Instead of the X-rays for excitation,
electron beam is also available forobtaining characteristic X-rays, and thismanner is already widely used as the
EPMA (electron probe micro analyzer)
analysis. This manner is also efficient for
the ultra-light elements, and, some ofthese members have already fabricated
EPMA system for the chemical state
analysis of ultra-light elements [1]. As
already shown in the Annual report inlast FY, the spectrometer for fluorescent
X-rays was already confirmed its
specification, and has been continue toadjustment at BL07A.
In last FY, the existence of some items
in both beamline and this spectrometer
was revealed, and the countermeasuresagainst these items had been executed. In
this report, two of these countermeasures
are presented.
Re-adjustment of spectrometer
Just before and after stopping of the storage
ring, the signal strength of the spectrometer had
become weak. The overview and schematic
illustration of this spectrometer is shown in
Fig.1. The important points of adjustment of

Fig.1
The overview and the schematic illustration of
the ultra-soft X-ray spectrometer.

22Fig.2 The CCD camera image of thescattered X-rays at the sample surface
path through the poly-capillary and slit
directly.

Fig.3
The CCD camera image of thezero-order light just after the adjustment.

this spectrometer are the alignment with
poly-capillary, slit and grating. Thus, before theadjustment of direction of poly-capillary, thealignment of the position of slit against theemission point of fluorescent X-rays on thesample surface path through the top ofpoly-capillary should be adjusted.
For this aim, whole of the part just after theslit system had been removed for the first. And,
CCD camera was connected for observing thebeam position which came from the sample
surface after the direction of poly-capillary wasset beside the optical axes mechanically. Then,
introducing the SR beam to sample surface, andthe slit holder was adjusted using micro
movement mechanism of the holder when thebrightest spot image on CCD camera wasobserved. The spot image just after the
adjustment is shown in Fig.2.
After the adjustment of slit position andthe re-construction of the spectrometer, therough alignment of the direction ofpoly-capillary was executed using thezero-order light beam of the grating tillobtaining the most homogeneous and brightimage on CCD camera. In Fig.3, the camera
image of the zero-order light just after the
adjustment is shown.
Finally, using the micro movement
mechanism of poly-capillary and the scattered
X-rays from the sample surface, the alignmentof whole system was adjusted.
After the all of above process, the normal
movement of this spectrometer was confirmed,
because the almost same bright image ofscattering X-rays was obtained.

Cleaning multi-layer mirror
In parallel with the adjustment ofalignment of spectrometer, the lowering of thestrength of the incident beam was also
investigated. There are two possible causes ofthe lowering; one is the carbon fouling on thesurface of switching mirror at the end of thefront-end system of BL07, and the other is thesame fouling on the multi-layer mirror (Mo/Si,
Mo/B4C and Ni/C ; these were fabricated on the
one piece of Si substrate.) of the beamline
monochromator.
The cleaning of switching mirror was
carried out by plasma ashing process aided by
the SPring-8.
On the other hand, there had been hard tofind any report about the cleaning of the surfaceof such kind of the multi-layer flat mirror for
beamline monochromator. Fortunately, Dr.T.
Harada (LASTI, Univ. Hyogo) et al. had
reported the cleaning process of the multi-layer
mirror surface of the reduction optical systemusing the combination of ozone and theexcimer ultraviolet light source. So, thecleaning process two multi-layer mirror ofBL07 was also carried out by cleaning system
set at BL03 with the great support of Dr.
Harada.
In Fig.4, the comparison of surface of themirror between just before and just after ofcleaning process is shown. In Fig.4(b), thesurface of mirrors just after about 10hrs
processing is shown. The foot print of theincident beam is clearly observed as the carbon
fouling. Fig.4(c) is just after about 20hrs. No

23the fluorescent X-rays will be re-started
as sson as possible.

fouling can be seen on the surface.
Present state and future
During 2015FY, as shown above,
almost all of the machine time had to be
consumed for the adjustment andtreatment of beamline components andequipment. Almost items against which
required any countermeasure wasseemed to be disappeared.
In this FY, all of the adjustment will
make to be finished, and e-started, theexamination of measurement condition of

Acknowledgement
The authors thank gratefully Dr. Tetsuo
Harada (LASTI, Univ. Hyogo) for the cleaningof multi-layer mirror, and Kazunori Tsukamoto
and Dr. Toyohiko Tazawa (JEOL ltd.) for the
adjustment of the equipment.
References[1] S. Fukushima et al. Microchim. Acta 161
pp.399-404 (2007)

(c)

(a)
(b)

Fig.4
The aspect of the multi-layer mirror surface.
(a) Just before cleaning.
(b) After about 10hrs. Lower is the 1st mirror of the beamline monochromator, and the foot print ofincident beam is clearly recognized.
(c) Just after cleaning (about 20hrs).
The black small solid circle images are the reflected images of the ceiling air duct.

24

Installation of Silicon Drift Detector for PFY-XAFS
Measurement of Insulating Materials in BL-09A
1

Shigeaki Uemura1, Junji Iihara1, Takashi Yajima2, Masahito Niibe3
Sumitomo Electric Industries, Ltd., 2Sumitomo Riko Company Limited, 3University of Hyogo

Abstract

We installed a silicon drift detector at BL-09A in NewSUBARU, in order to perform PFY-XAFS
measurements for insulating materials. We applied this technique to h-BN and polyimide andsucceeded to obtain good spectra.

Introduction
We are developing XAFS measurement
techniques for insulating materials such as
ceramics and resins. Last year, we succeededin the TEY-XAFS measurement forhexagonal boron nitride (h-BN) with
evaporated gold stripe, which was very
effective to reduce charge up [1].
In this study, we developed the
TFY-XAFS technique for the resin materials,
whose thermal stability is so poor that thegold stripe evaporation cannot be used.
Instead of the conventional photo diodedetectors, we attempted to utilize a silicon
drift detector (SDD), which enables us toobtain XAFS spectra even from charged up
specimens, realizing a superior energy
resolution, signal to background ratio, andsensitivity.

to the one that had been obtained by the
TEY-XAFS technique using gold stripe [1] .
This result demonstrates that the PFY-XAFS
technique is very useful to measure insulating
materials.
Then, we applied the PFY-XAFS
technique to poly imide (PI) films. We
prepared following two specimens: one isprocessed by a special surface treatment andthe other not processed.
Figure 5 shows the PFY-XAFS spectra of
the two PI films. There are four prominent
peaks, A, B, C and D, which are assigned to
C=C, C=O in pyromellitic anhydride(PMDA), O-C=O, and C=C in the
4,4-diamino
diphenyl
ether(ODA),
respectively [2]. We found that peak A and C
became larger while peak B became smaller
by the surface treatment process. Peak D
showed no significant change by thetreatment. As a possible mechanism, theincrease of peak B (O-C=O) and decrease ofpeak C (C=O) may suggest that the imide
rings cleave by the surface treatment, asshown in Fig. 6. Regarding the increase ofpeak A, further investigation will be required.

Installation of SDD
We installed an SDD of AMPTek, Inc.
(Type: X123SDD) at an ICF port of theanalyzing chamber in BL9A. The distance
between the SDD and sample is variable from50 to 250 mm (Fig. 1).
We modified the control program of BL9A
to obtain spectrum by the SDD at each energyof the incident x-ray, which enabled us to
optimize the region of interest (ROI) for
PFY-XAFS after the measurement. This wasvery useful to separate the fluorescence signal
from elastic scattering signal.
Figure 2 shows a distribution of thefluorescence intensity that was obtained froma highly oriented pyrolytic graphite (HOPG)
sample. The PFY-XAFS spectrum, which is
extracted with the ROI indicated by the blueline, is shown in Fig. 3.

References[1]
T.Yonemura,
J.Iihara,
S.Uemura,
K.Yamaguchi and M.Niibe, 2014
New
Subaru Annual report p.106-107[2] T. Tanaka, K. K. Bando, N. Matsubayashi,
M. Imamura and H. Shimada, Physica Scripta.
Vol. T115, 412-414 (2005)

Application of PFY-XAFS for insulating
materials
We applied the newly developed
PFY-XAFS measurement technique to theh-BN sample. Figure 4 shows the obtained
spectrum, which was found to be very similar

25

Fig. 4 B-K XAFS spectrum of h-BN.
(upper) PFY-XAFS (lower) TEY-XAFS.
Fig. 1 Attached SDD in an analyzing chamberat BL9A.

Fig. 5 C-K XAFS spectrum for Polyimides
with/without surface treatment
Fig. 2 Distribution of fluorescence intensity
obtained from HOPG.

Fig. 6 Cleaving of imide ring.

Fig. 3 C-K XAFS spectrum of HOPG.

26

Development of an analysis station for soft X-ray
absorption spectroscopy in BL10
Yasuji Muramatsu, Akinobu Tsueda, Tomoyuki Uemura, Keita Nambu, Takahito Ouchi, Tetsuo Harada,
Takeo Watanabe, and Hiroo Kinoshita
University of Hyogo
Abstract
A measurement station for X-ray absorption spectroscopy (XAS) has been developed andinstalled in BL10 at the NewSUBARU. The XAS station enables the soft X-ray absorption
measurements in 70 – 1100 eV region with a total electron yield (TEY) method. The station
will be widely utilized for chemical and/or local-structure analyses of light element materials.
twenty samples (5 x 5 mm2) can be mounted.

Introduction
A beamline BL10 has been developed as amulti-purpose soft X-ray beamline in
NewSUBARU (NS) [1]. Especially, it has been
mainly used for optical evaluation of multilayer
mirrors. However, optical properties of BL10 issuitable for X-ray absorption spectroscopy(XAS) in soft X-ray region, because BL10 has apotential to utilize soft X-rays ranging fromseveral tens eV to 1000 eV emitted from abending magnet source. Additionally, an analysis
station for soft X-ray absorption spectroscopy in
NewSUBARU has been required by materials
scientists. Hence, we have developed the soft Xray absorption analysis station, and installed it in
BL10. The present report briefly describes thedesign and performance of the XAS station [2-5].
Design of the XAS station
The XAS station has been designed basedon the following concepts;(1) Compact chamber to install the limited
narrow space of BL10.
(2) Simple and flexible chamber to easily
improve the measurement functions.
(3) Large sample plates can be loaded into themeasurement chamber for the efficientmeasurements. Many sample plates can also
be loaded in a sample-bank chamber.
(4) High speed pumping to enable themeasurements under the middle vacuum (~10-6 Torr).
(5) Position and angle of sample plate can beeasily adjusted by a four-axis stage.

Fig. 1 Photos of the XAS station (a), a mainchamber (b), and a sample plate (c).
Performance of the XAS station
Figure 2 shows X-ray absorption near-edge
structure (XANES) of standard samples
measured with three gratings (600, 1800, 2400mm-1) of BL10 monochromator. XANES
measured in BL10/NS are compared to those in
BL-6.3.2 at the Advanced Light Source (ALS).
The figure clearly shows that the high-resolution
XANES from Al L edge (~70 eV) to Zn L edge(~1100 eV) can be obtained in BL10/NS.
Figure 3 (left panel) shows the incidentangle(φ)-dependent C K-XANES of the highlyoriented pyrolytic graphite (HOPG) and carbon
black (CB). The spectra were taken with theincident angles of 15 ~ 90° (normal incidence).
HOPG
exhibits
strongincident-angledependence on the π* peak intensity. However,carbon black exhibits little angle dependence,

Based on the above concepts, the XAS chamber
has been developed and installed in BL10 asshown in Fig. 1. The XAS station consists of amain chamber and a sample-bank chamber. A
large ICF-305 φ pipe was used for the mainchamber, and the chamber was sealed with an Oring for easy access to the chamber. Size of asample plate (Cu plate) is 70 x 25 mm2, on which

27

However, Ca L peaks disappeared in used oilsamples. Intensity of O K peak became lower inused oil samples than in new oil sample. Thisshows that degradation of engine oil is not causedby oxidation. From the spectral analysis of C KXANES, it can be found that dissociation of
unsaturated bonds of oil polymers promotes thedegradation of engine oils.

because of the amorphous structure. The π* peakintensity as the function of cos2φ is also plottedin Fig. 3 (right panel). The measured data of
HOPG and carbon black can be wellapproximated with the linear functions. This
demonstrates that incident-angle-dependentmeasurements can be accurately performed by
the XAS station.

Fig. 2 XANES of standard samples measured by
the XAS station in BL10/NS, compared to
XANES measured in BL-6.3.2/ALS.

Fig. 4 XAS spectra of the engine oil samples.
References[1] T. Watanabe, H. Kinoshita, K. Hamamoto, M.
Hosoya, and T. Shok: LASTI Annual Report, 2,50-51 (2000).
[2] Y. Muramatsu, A. Tsueda, T. Harada, and H.
Kinoshita, Adv. X-ray Chem. Anal., Japan, 43,
407-414 (2012).
[3] Y. Muramatsu, A. Tsueda, T. Uemura, T. Harada,and H. Kinoshita, Adv. X-ray Chem. Anal., Japan,
44, 243-251 (2013).
[4] T. Uemura, Y. Muramatsu, K. Nambu, T. Harada,and H. Kinoshita, Adv. X-ray Chem. Anal., Japan,
45, 269-278 (2014).
[5] T. Uemura, Y. Muramatsu, K. Nambu, D.
Fukuyama, M. Kuki, T. Harada, T. Watanabe, andH. Kinoshita, Adv. X-ray Chem. Anal., Japan, 46,
317-325 (2015).

Fig. 3 Incident-angle dependent C K-XANES of
HOPG and carbon black (left panel). Right panel
shows the π* peak intensity as the function ofcos2φFigure 4 demonstrates chemical analysis ofliquid engine oils. The oil samples are new oil
and used oils driven for 4250 and 8900 km. The
liquid samples were dropped to clean gold
substrates, then synchrotron radiation beams
directly irradiated to the oil samples in themeasurement chamber under the 10-6 Torr
vacuum. XAS spectrum of new oil sample
exhibits peaks at C K, Ca L, and O K edges.

28Soft X-ray absorption spectroscopy (XAS) and X-ray
reflectivity (XRR) analysis system in BL10
Yasuji Muramatsu, Akinobu Tsueda, Tomoyuki Uemura, Keita Nambu, Takahito Ouchi, and Tetsuo Harada,
Takeo Watanabe, and Hiroo Kinoshita
University of Hyogo
Abstract
A measurement station for X-ray absorption spectroscopy (XAS) has been newly installed
upstream the X-ray reflectometer in BL10 at the NewSUBARU. By combination of theconventional X-ray reflectometer, XAS analysis and X-ray reflectivity (XRR) evaluation in soft
X-ray region can be performed in BL10. Chemical state and layer structure analyses of organic
thin films were demonstrated by using the XAS/XRR system.
Introduction
Recently, an analysis station for X-ray
absorption spectroscopy (XAS) has beendeveloped [1-3] and installed upstream the X-ray
reflectometer in BL10 at the NewSUBARU. The
XAS station enables the chemical/electronicstate analysis, and the X-ray reflectometer
enables layer structure analysis from the X-ray
reflectivity (XRR) measurements. Thus, the
XAS/XRR system can be a nice tool forevaluation of thin films composed of lightelements. The present report demonstrates thechemical and layer-structure analyses of organic
thin films using the XAS/XRR system [4].
Experiments
Figure 1 shows the XAS/XRR systemcomposed of the XAS and XRR stations, which
are installed in tandem. In the XAS station, asample plate can be rotated around a vertical axis,
which can analyze the orientation. On the other
hand, a sample plate can be rotated around a
horizontal axis in the XRR station, which cananalyze the angle-dependent X-ray reflectivity
and chemical analysis in depth direction.
Samples were prepared by Sumika
Chemical Analysis Service, Ltd. The measuredorganic films were vacuum deposition films of
N,N'-Di (1-naphthyl)-N,N'-diphenylbenzidin (αNPD) on Si substrates. Thickness of the films canbe estimated as approximately 100 nm.
Orientation of the α-NPD films was evaluated by
the incident-angle (φ) -dependent C K XANES(X-ray absorption near-edge structure) in the
XAS station. XANES in N K edge of the films
was also measured to analyze their chemical
states. Incident-angle (θ) -dependent XAS andXRR in the 200 – 600 eV region were
simultaneously measured in the XRR station.
XAS spectra were obtained with a total electron
yield (TEY) method in both XAS and XRRstations.

Fig. 1 Photograph of XAS and XRR stations in BL10.
Upper panel shows the layout of sample rotations.
Results and Discussion
Figure 2 shows the φ-dependent C K-XANESof the α-NPD films. It is confirmed that the α-NPD
films take no layer structure, because little φdependence was observed.

Fig. 2 φ-dependent C K-XANES of the α-NPD films,
measured with φ= 15 ~ 90°.

29

Figure 3 shows the simultaneously measured
TEY-XAS and XRR spectra in a 200 – 600 region of
the α-NPD films. In XAS spectra, interference
structures can be clearly observed below the C K
edge, which are dependent on the incident angle θ.
Absorption peaks in C K and NK regions can beclearly obserbed, because α-NPD is composed ofcarbon and nitrogen atoms. Little peak can beobserved in O K edge even in the shallow angle of
5.23°. This means that surface of the α-NPD film is
not oxidized. In XRR spectra, interference structures
can be clearly observed in the 200 – 600 eV range,
which depend on θ. This clarifies that the α-NPD
films were deposited as uniform layers.
Fig. 4 Upper panel (a) shows the calculated XRR
spectrum (solid line) of the α-NPD/SiO2/Si system,compared to the measured XRR spectrum (dottedline) of the α-NPD film sample. Lower panel (b)shows the calculated XRR spectrum shifted with
+3.2 eV.
Acknowledgements
We would like to express thanks to Dr. Shogo
Suehiro of Sumika Chemical Analysis Service, Ltd
for his preparation of the α-NPD film samples.
References[1] Y. Muramatsu, A. Tsueda, T. Harada, and H.
Kinoshita, Adv. X-ray Chem. Anal., Japan, 43,
407-414 (2012).
[2] Y. Muramatsu, A. Tsueda, T. Uemura, T. Harada,and H. Kinoshita, Adv. X-ray Chem. Anal., Japan,
44, 243-251 (2013).
[3] T. Uemura, Y. Muramatsu, K. Nambu, T. Harada,and H. Kinoshita, Adv. X-ray Chem. Anal., Japan,
45, 269-278 (2014).
[4] T. Uemura, Y. Muramatsu, K. Nambu, D.
Fukuyama, M. Kuki, T. Harada, T. Watanabe, andH. Kinoshita, Adv. X-ray Chem. Anal., Japan, 46,
317-325 (2015).

Fig. 3 Simultaneously measured TEY-XAS (a) andXRR (b) spectra of the α-NPD film sample,
measured with θ = 5.23, 10.28, 15.20, and 20.15°.
To determine the thickness of the α-NPD films on Si
substrates, XRR spectra taken with θ = 20.15° was
simlated as shown in Figure 4. The simulations were
performed by using the optical calculation softwareof the Center for X-Ray Optics (CXRO).
Interference structures were fitted below and above
the C K edge. Slight phase shift of 3.2 eV wasobserved at the C K edge. In the both regions, themeasured interference structure can be well fitted by
the simulations with parameters of 102.5 nm
thickness of α-NPD film on a SiO2/Si substrate. This
calculated thickness agrees to the estimatedthickness of 100 nm.
In conclusion, the XAS/XRR system in BL10
is a powerful tool to evaluate chemical/electronicstates and layer structures of organic thin film
samples.

30

31

32

Development of LCS Gamma-Ray Simulation Codeand GUI Application
Satoshi Hashimoto, Takuya Matsumoto, and Shuji Miyamoto
LASTI

Abstract
We are developing a simulation codes on Laser Compton Scattering Gamma-Ray generation and
its Graphical User Interface application. These codes can make possible the numericalreproduction of the complex LCS experiments, the easy execution of the simulation for users, andthe data visualization.
Introduction
The beamline BL01 of NewSUBARU
synchrotron light facility [1] is one of the
few Laser Compton Scattering (LCS)
Gamma-ray facilities in the world.
Using
LCS
Gamma-ray
atthe
NewSUBARU, user experiments such as
HARPO project [2] have been performed.
The LCS Gamma-ray source iscomposed from many systems such as anelectron accelerator, laser systems, opticalcomponents, collimators, detectors.
We are developing the LCS simulation codethat can reproduce the realistic experiments.
And also we have developed the useful GUI
program for easy execution of the simulation.
These codes can run in cross-platform
environments (Linux, OSX, Windows).

Further upgrade of the code is in progress,
that is, a code due to the Monte-Carlo methodwith many numerical particles in order to becloser to reality.
GUI Application
The Fortran simulation code reads lots ofparameters from input files and writes the huge
numerical data to output files.
For easy
execution by users, we also developed aGraphical User Interface (GUI) program. The
GUI program is separated from the simulation
code and written using Python and its graphicaltoolkit, WxPython. Users can easily edit, loadand save input parameters, execute thesimulation code, visualize output data on the
GUI panel. Typical GUI panels are shownin Fig.2.

LCS Gamma-ray Simulation code
The simulation code we are developing isbasically based on theoretical works [3,4] and iscoded with Fortran. At first we developed thecode according to a simple 1D model
approximately including the effects of finite
emittances of the electron and laser beams.
Intensity graphs of gamma photons when ahorizontally polarized laser beam with finite
radius collides with an electron beam with finite
emittance are shown in Fig.1. Simulation
result agrees well with measurement.
Fig.2 GUI front panels for the LCS simulation.
References[1]http://www.lasti.u-hyogo.ac.jp/NS-en/facility/bl01/[2] S.Wang, D.Bernard, et al., 7th Symposiumon Large TPCs for Low-Energy Rare Event
Detection, Paris, 15-17 December 2014.
[3] V.N.Litvinenko, J.Madey, SPIE vol. 2521,
55-77[4] C.Sun and Y.K.Wu, Phys.Rev.ST Accel.
Beams 14: 044701,2011

Fig.1 Intensity plots of LCS gamma-ray by thehorizontally polarized laser photons. Measured
by an imaging plate (left) and simulation (right).

33

Measurements of neutron energy spectra depending on theemission angle due to photo-nuclear reaction using LCS
photons
Yoshihiro Asano1,5, Toshiya Sanami1,2, Hiroshi Nakashima1,3,
Yoichi Kirihara2, Toshiro Itoga4, Yoshihito Namito2,
Akinori Takemoto5, Masashi Yamaguchi5 , Shuji Miyamoto5
1

RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan,
High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
3
Japan Atomic Energy Agency, 2-4 Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1195, Japan
4
JASRI, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
5
University of Hyogo, 1-1-2, Koto, Kamigori-cho, Ako-gun, Hyogo 678-1205, Japan
2

Abstract

Neutron energy spectra due to photo-nuclear reactions from natC and 197Au targets were measured
with polarized photon beams using the time of flight and pulse shape analyses methods at the
NewSUBARU-BL1 beamline. The dependence on the azimuthal angle and polar angle for theneutron energy spectra was found in the photonuclear reaction for the linearly and the circularly
polarized photons. The difference on the neutron yield increases with neutron energy in theazimuthal angle for linearly polarized photons and in the polar angle in comparison with linearlyand circularly polarized photons.

Introduction
To construct the high-energy electron
machines, one of the crucial issues is theradiation protection such as the estimation ofleakage dose distribution and induced
activities. Sometimes, the design of theradiation shielding restricts the machine
designs.
To investigate the physicalphenomena of neutrons due to photo-nuclear
reaction is important because of insufficientexperimental data in addition to its strong
attenuation and the cause to activate thecomponents. The double differential crosssection data that fully describe energy andangle of the emitted neutrons are required todesign and estimate the shielding andleakage dose distributions. However, there
are few experimental data of the double
differential cross section until now. In
addition, the azimuthal angle dependence ofemitted neutrons due to polarized photons
was reported experimentally [1]. The
dependence on the photon polarization for
the neutron due to photo-nuclear reaction
will be more important. For example, at theInternational
LinearCollider(ILC),
experiments with the polarized electron andpositron beam of 250 GeV will be performed
and the polarized photons are produced by
the polarized electron with undulator [2] sothat the shielding design of the ILC facility
should consider the influence of the polarized

photons.
A linearly and circularly polarized Laser
Compton Scattering (LCS) γ-ray beams withquasi-monochromatic energy up to 76 MeV
are available at NewSUBARU-BL01 [3], [4].
To investigate the double differential crosssection of neutron production due tophoto-nuclear reaction systematically for
giant
dipoleresonance(GDR)
andquasi-deuteron disintegration (QDD) region,
we have measured the neutron spectra at theseveral directions from the photonuclear
reaction with the linearly and circularly
polarized photon using liquid scintillation
counters
with
gold
and
graphitetargets[5],[6].
Experiments and Results
Experimental set-up is shown in Photo.1
and Fig.1. Two collimators, one is 6mm
diameter in upwards and the other is 4mm indownwards, were employed to define the LCS
γ-ray spectra for the natC target experiments,and 3mm and 2mm diameters for the gold
target experiments. The intensities of LCS
photon were measured by GSO scintillation
counters and monitored by thin plastic
scintillation counter (PLS). The separation ofphotons and neutrons were performed byusing time of flight and the pulse shapeanalyses methods of the liquid scintillation34

counters with the size of 127mm in diameterand 127 mm long.
The photon maximum energies of 23.1
MeV and 26.6MeV were employed for the natCtarget experiments with the Nd:YVO4 laser(wave length, 1064nm) and 1.14 GeV and
1.22GeV electrons, respectively. In theexperiments, a λ/4 wave plate of the laser
was employed to avoid the polarization effect.
Figs.2 and 3 show the measurement resultsof neutron spectra for 23.1MeV and 26.6MeV
photons, respectively. In these figures, H60°
and H90° means the detector positions at thepolar angles of 60 and 90 degrees in thehorizontal plane. V90° means the position at
the azimuthal angle 90 degrees in verticalplane. As shown in figures, the neutrons dueto photo-nuclear reactions seem to be an
isotropic distribution over a wide energy
range.

Fig.2 Neutron spectra due to natC(γ,n)
reaction with 23.1 MeV photons. Red lines
indicate the maximum neutron energy ofthese reactions for 12C and 13C.

Fig.3 Neutron spectra due to natC(γ,n)
reaction with 26.6 MeV photons. Lines andsymbols are same as Fig.2.

Photo.1 Experimental setup in the hutch 2 ofBL1 beamline.

In the case of gold target experiments, thepurpose is to obtain the effect of the neutron
spectrum due to photon polarization so thatthe gold target was employed with theelectron energy of 982.4MeV and 16.95MeV
of maximum LCS photon energy. The reasons
are that the cross section of the gold forphoto-nuclear reaction is large and theelectron energy of 982.4MeV is easier tooperate the single bunch mode and top-up.
Fig.4 shows the energy dependence of theemitted neutrons due to linearly andcircularly polarized photons. In this figure,the vertical axis shows the ratio of theneutrons in the lateral direction of 0 and 90
degrees of azimuthal angle due to linearly or
circularly polarized photons. The linear
polarization of the LCS photons was set at

Fig.1 Illustration of the setup of experiments.
V.90°,H60°,H90° means liquid scintillation
counters which install in horizontal (H60° andH90°) and vertical (V90°) planes. PLS means athin plastic scintillation counter.

35difference on the neutron yields increases
with neutron energy. There is no influenceof the polarization on the neutron energy
spectrum for the same direction as thelinear polarization. The right angle to thedirection of the linear polarization, theneutron yield decreases with increasing
neutron energy. The results clearly pointout that the difference in neutron yieldand the dependence on the neutronenergy should be taken into account forshielding design of the facility with thepolarized
photons.
Howevertheexperimental data of double differential
cross section with photon polarization
effect are quite insufficient so that thesame experiments with different material
targets and different photon energy,
especially higher energies should be
performed continuously.

the azimuthal angle of 90 degrees (the V90°
direction). The results show that the ratio
increases with neutron energy for the
linearly polarized photons. On the other
hand, the ratio is approximately constant forthe circularly polarized photons. Figure 5
shows the ratio of the neutron yields for the
linearly polarized photons to that for thecircularly polarized photons. For the V90°
direction, the ratio is almost constant inwhole neutron energy. It indicates that there
is no energy dependence on an influence ofthe polarization for the same direction as thelinear polarization. For the H60° and H90°
directions that are the right angle to thedirection of the linear polarization, the ratios
decrease with increasing emitted neutronenergy.

Fig.4 Energy dependence on the photon
polarization for the emitted neutron due tophoto-nuclear reaction. (The ratio of the neutron
yields for the V90° direction to those for the
H90°.)

Fig.5 Energy dependence on the photon
polarization for the emitted neutron due tophoto-nuclear reaction. (The ratio of the neutron
yields at each direction for the linearly to that forthe circularly polarized photons.)

Conclusions
To investigate the double differential
cross section of neutron emission due tophoto-nuclear reaction, we measured theneutron spectra generated from thenatural graphite and gold targets due tothe photo-nuclear reaction by thepolarized laser Compton scattering
photon beams of 23.1 MeV, 26.6MeV, and16.95MeV with the time-of flight and thepulse shape analysis methods at
NewSUBARU-BL01 beamline. As theresults, the emitted neutron spectra
without polarization effect show almost
isotropic distribution, and the neutron
yield, which is set at the same direction as
the photon linear polarization, is higher
than the yields of the other directions. The

References[1] K. Horikawa et al., Phys. Lett. B 737, 109 (2014)[2] International Linear Collider Technical Design
Report,https://www.linearcollider.org/ILC/Publications/Technical-Design-Report[3] S. Miyamoto, et al., Radiat. Meas. 41, S179 (2007)[4] Y. Asano, et al., Progress in Nucl. Sci. & Tech. 4,254 (2014)[4] D. Satoh, S. Kunieda, Y. Iwamoto, N. Shigyo and
K. Ishibashi, Nucl. Sci. Tech. 2 657 (2002)[5] T.Itoga, et.al., To be published in theproceedings of 13th International Conference on
Radiation Shielding, Paris France Sep.2016[6] Y.Kirihara et.al., To be published in theproceedings of 13th International Conference on
Radiation Shielding, Paris France Sep.201636

Photoneutron Reactions in Nucleosynthesis
Hiroaki Utsunomiya
Department of Physics, Konan University, Kobe, Japan

Abstract

The development of laser Compton scattering γ-ray beams has highlighted the role ofphotoneutron reactions in the p-process, s-process, and applications to light nuclei innucleosynthesis. Among (γ, n), (γ, p) and (γ, α) photo-reactions and (p, γ) capture reactions
complemented by β-transformations, neutron removal reactions play a major role in the p-process
nucleosynthesis.

The development of laser Compton scattering γray beams has highlighted the role of photo-neutron
reactions in the p-process, s-process, andapplications to light nuclei in nucleosynthesis.
Among (γ, n), (γ, p) and (γ, α) photo-reactions and(p, γ) capture reactions complemented by βtransformations, neutron removal reactions play amajor role in the p-process nucleosynthesis [1].
The methodology called the γ-ray strength
function method [2] has been devised to study
radiative neutron capture cross sections for unstable
nuclei at the s-process branch-point based on aunfied understanding of (n, γ) and (γ, n) crosssections. This method has been applied to 17
elements (Se, Ge, Mo, Zr, Pd, Sn, La, Pr, Nd, Sm,
Dy, Ta, W, Re, Os, Au, Pb) and 51 isotopes
including the application in the rare-earth region[3,4]. Radiative capture reactions on light nuclei arealso studied by photonuclear reactions based on thereciprocity theorem. Recently, photodisintegrationof 9Be was re-examined in the context of explosive
nucleosynthesis of 9Be through α+ α ⇄ 8Be(n,J. Koning, “Photoneutron cross sections fors a m a r i u m i s o t o p e s : To w a rd a u n i f i e dunderstanding of (γ ,n) and (n,γ ) reactions in therare earth region“, Phys. Rev. C 90, 064616(2014).
[4] H.-T. Nyhus, T. Renstrøm, H. Utsunomiya, S.
Goriely, D. M. Filipescu, I. Gheorghe, O.
Tesileanu, T. Glodariu, T. Shima, K. Takahisa, S.
Miyamoto, Y.-W. Lui, S. Hilaire, S. Péru, M.
Martini, L. Siess, and A. J. Koning, “Photoneutron
cross sections for neodymium isotopes: Toward a
unified understanding of (γ ,n) and (n,γ ) reactionsin the rare earth region”, Phys. Rev. C 91, 015808(2015).
[5] H. Utsunomiya, S. Katayama, I. Gheorghe, S.
Imai, H. Yamaguchi, D. Kahl, Y. Sakaguchi, T.
Shima, K. Takahisa, and S. Miyamoto,“Photodisintegration of 9Be through the 1/2+ stateand cluster dipole resonance“, Phys. Rev. C 92,
064323 (2015).
[6] P. Carlos, H. Beil, R. Bergere, A. Lepretre, A.
Deminiac, and A. Veyssiere, Nucl. Phys. A 225,
171 (1974).

γ)9Be [5]. The role of photonuclear reactions in
nucleosynthsis will be strengthened in the ELI-NP
which is under construction in Bucharest-Măgurele.
I review the latest experimental developments ofphotoneutron reactions in nucleosynthesis and give
future prospect of the field.
References[1] H. Utsunomiya, P. Mohr, A. Zilges, M. Rayet,“Direct determination of photodisintegration crosssections and the p-process”, Nucl. Phys. A 777, pp.
459-478 (2006).
[2] H. Utsunomiya, S. Goriely, M. Kamata, T. Kondo,
O. Itoh, H. Akimune, T. Yamagata, H. Toyokawa,
Y. -W. Lui, S. Hilaire, “γ-ray strength function for
116,117Sn with the pygmy dipoleresonance balancedin the photoneutron and neutron capturechannels”, and A. J. Koning, Phys. Rev. C 80,
055806 (2009).
[3] D. M. Filipescu, I. Gheorghe, H. Utsunomiya, S.
Goriely, T. Renstrøm, H.-T. Nyhus, O. Tesileanu,
T. Glodariu, T. Shima, K. Takahisa, S. Miyamoto,
Y.-W. Lui, S. Hilaire, S. Péru, M. Martini, and A.

(a)

37

(b)

(f)

(c)

(g)
Figure 1. Measured photoneutron cross section of
Sm isotopes, (a) 144Sm, (b) 147Sm, (c) 148Sm, (d)149Sm, (e) 150Sm, (f) 152Sm, (g) 154Sm. Red points
are present data. Comparison between the present
cross sections and previously measured ones [6].
Also included are the predictions from Skyrme
HFB+QRPA (based on the BSk7 interaction) andaxially deformed Gogny HFB+QRPA models(based on the D1M interaction)[3].

(d)Figure 2. The present 9Be(γ,n) cross section (■) incomparison with the existing data.

(e)

38

Total and partial photoneutron cross section measurements bydirect neutron-multiplicity sorting
Hiroaki Utsunomiya, the Phoenix* Collaboration
Department of Physics, Konan University, Kobe, Japan

Abstract

I coordinate the Phoenix Collaboration for the IAEA(International Atomic Energy Agency)CRP(Cordinated Research Program) F41032 to provide new data of total and partial (γ, xn) crosssections with x=1-3 for 11 nuclides for updating the photonuclear data library in collaboration with
the Skobeltsyn Institute of Nuclear Physics of the Lomonosov Moscow State University and theExtreme Light Infrastructure-Nuclear Physics (ELI-NP) and new data of (γ, n) cross sections for
18 nuclides for generating a reference database for photon strength functions (PSF) in
collaboration with the University of Oslo. (*Photoexcitation and neutron emission cross (x)sections.)

I coordinate the Phoenix Collaboration for the
IAEA-CRP F41032. The Phoenix Collaboration
Team is as Figure 1. The purposes of this research
project are to provide :discrepancy between the Livermore and Saclay
data of total and partial photoneutron cross sections
and provide PSF data twofold, in the context of a
unified understanding of (γ, n) and (n, γ) crosssections over isotopic chains with the γ-ray strength
function method and a construction of the PSF by
combining the (γ, n) data and the data obtainedwith the Oslo method.
The experiments will be performed at the
NewSUBARU synchrotron radiation facility(Figure 2) using quasi-monochromatic γ-ray beams
produced in the inverse Compton scattering of
1064nm and 532nm laser photons with relativistic
electrons. The (γ, xn) data will be taken with theflat-efficiency neutron detector (Figure 3.) recently
developed for direct neutron-multiplicity sorting,while the (γ, n) data with the high-efficiency
neutron detector as long performed in the past.
The Konan, MSU, ELI-NP, and Oslo teams are1) new data of total and partial (γ, xn) crosssections with x=1-3 for 11 nuclides from 209Bi to
9Be for updating the photonuclear data library incollaboration with the Skobeltsyn Institute of
Nuclear Physics of the Lomonosov Moscow State
University and the Extreme Light InfrastructureNuclear Physics (ELI-NP) and2) new data of (γ, n) cross sections for 18
nuclides from 205Tl to 58Ni for generating areference database for photon strength functions(PSF) in collaboration with the University of Oslo.
The main purpose of the Phoenix Collaboration
is to resolve the long-standing problem of the

NewSUBARU facility
S.Miyamoto, S.Amano

ULB
S.Goriely

Moscow State University
S.Belyshev, A.Kuznetsov,
K.Stopani

Production of γ-ray
beams, Laser system

γ-ray strength function
TALYS data evaluation(γ, xn) cross section
103Rh, 89Y, 59Co

Kyoto University
H.Ohgaki

Konan University
H.Utsunomiya,
S.Katayama

ELI-NP
D.Filipescu
I.Gheorghe

γ-ray beams monitoring
JAEA
F.Kitatani, O.Iwamoto,N.Iwamoto(γ, xn) cross section
197Au, 181Ta, 139La(γ, n) cross section
160Gd, 158Gd, 157Gd,
156Gd, 64Ni, 60Ni, 58Ni

(γ, xn) cross section
169Tm, 165Ho, 159Co
University of Oslo
S.Siem, A.-C.Larsen
G.Tveten, T.Renstrøm(γ, xn) cross section

Photo activation
CCONE data evaluation

192Os, 185Re, 184W, 183W,
182W, 68Zn, 66Zn, 64Zn

Figure １. Teams and members of Phoenix Collaboration.

39

assigned their own (γ, xn) and (γ, n) data as
follows.

2. (γ, n) data for 18 nuclei for generating areference database for photon strength functions-The Konan team: 160Gd, 158Gd, 157Gd, 156Gd,
64Ni, 60Ni, 58Ni
-The Oslo team: 205Tl, 203Tl, 192Os, 185Re, 184W,
183W, 182W, 89Y, 68Zn, 66Zn, 64Zn

1. (γ, xn) data with x=1-3 for 11 nuclei for updating
the photonuclear data library-The Konan team: 197Au, 181Ta, 139La, 9Be-The ELI-NP team: 209Bi, 169Tm, 165Ho, 159Tb-The MSU team: 103Rh, 89Y, 59Co

Figure 2. The beam-line BL01 for γ-ray production and the experimental hutch GACKO at
NewSUBARU.

(a)

(c)
Figure 3. The newly developed flat
efficiency neutron detector system. (a)Photograph outside. (b)Layout of the 3He
detector in the polyethylene moderator.
(c)The calculated neutron detection
efficiency of three 3He detector rings as afunction of the neutron energy.

(b)

40

First characterization of a time projection chamber as ahigh-performance gamma-ray pair-creation telescope andFirst characterization of a time projection chamber as apolarimeterhigh-performance gamma-ray pair-creation telescope andDenis Bernard
polarimeter
LLR, Ecole Polytechnique & CNRS/IN2P3, France
Denis Bernard
LLR, Ecole Polytechnique & CNRS/IN2P3, France
Abstract

Abstract

WeWe
have
exposeda timechamberchamber(TPC) to(TPC
the polarized
providedbeam
by thehave
exposeda projection
time projection) to the gamma-ray
polarized beam
gamma-ray− -pair
BL01
laser Compton
scattering(LCS)
beam line
at NewSUBARU.
More
than
million gamma-to-e
providedby the BL01
laser
Comptonscattering(LCS) beam
line
at 60
NewSUBARU.
More+ ethan+−
conversion
events
were
taken
in
the
gamma-energy
range
1.7
–
74
MeV.
Preliminary
resultsoftheon-going
60 million gamma-to-e e -pair conversion events were taken in the gamma-energy range 1.7
analysisthese Preliminary
data show the results
excellentofbehaviorof the detector
despitethe high
particle
fluxtheandexcellent
for the first– 74 ofMeV.
the on-goinganalysisof these
data
show
time
we
demonstratehigh-performancepolarimetry,inthe
MeV-GeVenergyrange,
withaspace-compatible
behavior of the detector despite the high particle flux and for the first time we demonstratetechniquesuch as a TPC.polarimetry, in the MeV-GeV energy range, with a space-compatible
high-performancetechniqueas a TPC.
Severalclasses suchof cosmic
sources such as active ful tool for understanding the mechanisms at work ingalactic nuclei (AGN), pulsars and gamma-ray bursts cosmic sources at low energies (from radio to X-rays)(GRB)
producehuge
gammasuchrays.as active
These has
neverbeen performed
abovebecome
1 MeV: ineffective
Compton poSeveral
classesof flows
cosmicofsources
MeV:
Comptonpolarimetersathigh-energy
photons
are produced
by non-thermal
becomeat high
not onlyhigh energies
notineffective
only because
theenergies
cross sectionisgalactic nuclei(AGN),
pulsars andgamma-ray larimeters
processes
such produce
as synchrotron
radiationand inverse
the crosssection isbut becausethedecreasing
but because
thedecreasingpolarization
asymmetrybursts (GRB)
huge flows
of gamma
rays. because
Comptonscattering, andprovideto enable
us polarization
1/Escopes,[1]. Foragain
pair tele[1]. For falls
pair asteleit’s
falls as 1/Easymmetry
These high-energy
photons
are insightproducedby nonmultiple
scattering
that
ruins
the
azimuthal
thermalprocesses
suchassynchrotron
radiationandto understand the structure of these sources and the scopes, again it’s multiple scattering that ruins the azinformation
carriedby thepairpairas assoon
inverse Compton
scattering,emissionmechanisms
at work. and provide insight to imutal
information
carriedby thesoonasasaa few
few−3
enable us to understand the structure of these milli-radiation
X
)
away
from
the
conlengths(10−30
In the 0.01 – 1 MeV energy range, Compton tele- milli-radiation lengths (10 X0) away from the consources and the emission mechanisms at work.
version point [2].
scopes are extremely efficient. In the 0.1 – 1000 GeV version point [2].
In range,
the 0.01
1 MeV
range, telescopes
Comptonenergypast–andpresentenergy
pair-creation
tele- scopes are extremely efficient. In the 0.1 –are extremely efficient. In between lies a “sensitivity
1000 GeV energy range, past and present pairgap”, namely the energy range 1 – 100 MeV, in which
creation telescopes are extremely efficient. In
very
few high-sensitivity
observationsof gamma-ray
betweenlies a “sensitivitygap”, namely
the energy
emitting
cosmicsourcesareavailable.
the high“pairrange 1 – 100 MeV, in which veryOnfewside”,
performancedegradesstronglyatlowenergysensitivity observations of gamma-ray emitting
becauseangularbecosmic thesourcesare resolution
available. isOnextremely
the “pairlowside”,
causeof the multiple
scatteringof theperformancedegradesstrongly
at pair
low electronsenergythe angularresolution
is extremely
beinbecause
the convertermaterial(most often
tungstenlow
slabs):
causethoughof the multiple
scatteringof the pairelectrons
Even
the pair-creationthresholdis at
1 MeV,
in Fermi-LAT
the convertermaterial for(mostoften has
tungstentheCollaboration,
example,barelyslabs):
Even
thoughthepair-creationthresholdis atpublished any observation below 100 MeV.
1 MeV, the Fermi-LAT Collaboration, for example,
Mostradiationmechanisms
mentioned below
above prohasbarelypublished
any observation100
duce
linearlypolarized
g-rays,tosomeextent,while
MeV.
Figure1: 3Ddrawingof the HARPO
detector.
Figure1. CAD
3D CADdrawingof the HARPO
phenomena such as magnetic field turbulence tend to
Most radiation mechanisms mentioned above
detector.
dilutethe linearlypolarizationof theγ-rays,
overalltoradiation
emitproduce
polarized
some extent,
ted
by
a
given
source.
Incontrast
totheseradiativeThe
present
work
is to
the
while phenomena such as magnetic field turbulence
Theaimaimofofthethe
present
work
is demonstrate
to demonstrateemissioninteractions
bary- potentialof a low-density(gas), (gas),
homogeneous
detectend to mechanisms,
dilute the hadronic
polarizationof the ofoverall
the potentialof a low-density
homogeneousonic
high-energy
cosmicrays (protons
or contrastions) withradiation
emit- tedby a given
source. In
to torfor high-performance(angular(angularresolutionresolution
and sendetector
for high-performancematterrest produce
non-polarized
photons hadronic
via spin- sitivity)
these atradiativeemissionmechanisms,
gamma-raygamma-ray
astronomy [3]and polarimetry[4]
and sensitivity)
astronomy[3] and0interactions
p 0 decay. of baryonic high-energy cosmic rays in the MeV-GeV energy range, using nuclear1 conver+ e− Z.
(protons or ions) with matter at rest produce non- sions
pairs, g Zthe
! eanalysis
1Intoprinciple
The measurement of the linear polarization (fractionof the recoil electron
polarized photons via spin-0 π0 decay.
azimuthal
distribution
for electron
triplet conversion
1 In principleangle
and Theangle)measurementof the emission,
which
is
such
a
powertheanalysisoftherecoilazimutal angleof the linear polarization− ! e+ e− e− ) should−+−−
distribution
fortripletconversion
events(geee)
shouldenableus
to perform→eevents(γe(fraction and angle) of the emission, which is suchpolarimetry
too
[5].
In
practicethough,the crossa powerful tool for understanding the mechanisms
sectionforalarge
enoughrecoilelectronat work in cosmic sources at low energies (from 1
momentum is much too small to perform aradio to X-rays) has never been performed above 1
measurement on a cosmic source [3, 4].

41

Figure 2. Layout of the HARPO detector in the GACKO experimental hutch on the BL01 beam
Figureline. 2: Layout of the HARPO detector in the GACKO experimental hutch on the BL01 beam line.
polarimetry [4] in the MeV-GeV energy range,

Monochromaticity was obtained by collimatingtheγ beam onofaxis.
In thatcase,is thepolarizationand direction)
the laserbeamtransferredto the(fraction and direction) of the laser beam isg-beam. We took most of the data with fully polarizedtransferred to the γ-beam. We took most of the databeams
(P ⇡ 1). Part of the data was also taken with anwith fully polarized beams (P ≈ 1). Part of the data
unpolarized
beam
(P ⇡
which means
here(Prandom
was also taken
with
an 0,unpolarized
beam
≈ 0,
linearpolarization),soastobettercontrol
the possible
which means here random linear polarization),sosystematic
biascontrol
inducedthe fact thatthe detector
as to better
thebypossible
systematic
bias isnotcylindricallythe x, y, z is
structureinducedby thesymmetric:
fact that indeed
the detector
notcylindricallythesuchx, y,biases.
z structureofthe detectorsymmetric:
was found indeed
to induce
Figurethe detector
wasto induce setup.
such biases.
2ofshows
the layoutof foundthe experimental
Figure 2 shows the layout of the experimental
The weak point of TPCs is that they generate a huge
setup.
flow of information that is incident on the digitizing
The weak point of TPCs is that they generate aelectronics,
case 2⇥288
to be dealt
withhuge flow inof ourinformation
thatcharges
is incident
on the
every
30
ns,
with
the
consequence
that,
with
a
storagedigitizing electronics, in our case 2 × 288 charges
depth
511withtimeeverybins, 30
thens,
durationof thedigitization
to be ofdealtwith theconsequenceofan witheventacanbe asdepth
long asthat,storageof 1.7511ms.
timeTherefore,bins, the toduration
digitizationof an event noise
can beascope
withofthethehuge
rate of backgroundmainlylongtoastracks
1.7 ms.
to cope withthe huge
due
fromTherefore,
g-ray conversions
upstreamof therate of backgroundnoise mainly
to tracks
fromdetectoror of the detector
gas, wedue
have
designedand
γ-rayconversions
upstreamofthedetector
orofused a sophisticated trigger system that allowed the
us todetectorgas, webyhave
and usedarejectbackgroundmore designed
than two ordersof magnisophisticated trigger system that allowed us totude while the overall trigger efficiency on the signal
reject background by more than two orders of(ie.
g conversions
to pairs
in trigger
the TPCefficiencygas) was on
kept
magnitude
while theoveralllarger
than
50
%
[14].
the signal (i.e. γ conversions to pairs in the TPC

A TPC[6, 7]1 conversions
is a volumetofilled
matter,pairs,with
γZ→
e+e−Z.here
using
nuclearan argon-basedgas,
in an electricfield,here
here
A TPC [6, 7]
is immersed
a volume filledwith matter,homogeneous.
Afterahigh-energy“event”hastaken
an argon-based gas, immersed in an electric field,
place
the gas, for usAfterg ! ae+high-energye− , the two “event”
leptons ionhereinhomogeneous.
has
The twoionizetaken
the gason theirpathandforexitustheplacein thegas,
γ detector→ e+e−,2 theleptons
ionize theon theirtheizationelectrons
driftgas(oppositeto)pathalongandtheexitelectric
2 The ionization electrons drift (opposite to)detector
field and are collected on the TPC “endplate” anode.
electric field
and are collected
the of
TPC
Wealong
havethesegmented
the endplate
into two on
seriesor“endplate”
anode.
We
have
segmented
theendplatethogonal strips, the charge collected by each providing
into two series of orthogonal strips, the charge
two projections on the x and y “transverse” directions,collected by each providing two projections on therespectively,of the signalthat is arriving
at theofendx and y “transverse”
directions,
respectively,
the
plate
at
a
given
time
t.
The
measurementof athegiven
drift
signal that is arriving at the end- plate at
durationt − tmeasurement
time, provides
0 , where t0 isofthetime t. The
theevent
drift durationt − t0,thewheremeasurementof thethird time,“longitudinal”
coordit 0 is theevent
providesthenate,
z. Duringofmostof the“longitudinal”
datataking atcoordinate,
NewSUBmeasurement
the thirdz. Duringof the data taking
NewSUBARU
we usedmost
an argon-isobutane
95-5%at mixture
at a
ARU
we
used
an
argon-isobutane
95-5%
mixtureatpressure of ⇡ 2.1 bar. The presence of a small
amountapressure
of
≈
2.1
bar.
The
presenceofasmall
of multi-atomic molecules limits the “heating” of theamount byoftheirmulti-atomic
molecules
limitstheelectrons
multiple collisions
duringthe drift“heating” of the electrons by their multiple
and therefore decreases the value of the diffusion cocollisions during the drift andptherefore decreases
Figuredown
1 shows
efficientdownoftothe
about
0.03 cm/the value
diffusionco- cm.
efficienttotheaboutlayoutof theHARPO
detector[11]. the layout of0.03
cm/√cm.
Figure1 shows
thedetector[11].place in November 2014.
TheHARPO
data taking
took
Theweredata produced
taking tookbyplace
Novemberscattering
2014. γg-rays
laserin Compton
rays
were
producedbylaserComptonscattering(LCS) of a laser beam on the high-energy (GeV) elec(LCS)of ina laserbeam on the storagehigh-energy
(GeV)
trons
storedthe NewSUBARU
ring [12,13].
electrons
storedinthe
NewSUBARU
storagering
Tuning the electron energy in the range 0.6 – 1.5 GeV[12, 13]. Tuning the electron energy in the range 0.6
and using lasers with various wavelenths (Nd:YVO4– 1.5 GeV and using lasers with various
1wwavelengths
and 2w, CO(Nd:YVO
we were able to vary
2 and Erbium),
4 1ω and 2ω, CO2 andtheErbium),Compton-edge
fromthe1.7Compton-edge
to 74 MeV. γ
we wereg-energy
able to varygas)
was kept
largera than
50 %Figure3 shows
sampleof[14].
events. The analysis
Figureshows
sample of[15].
events.
The analysisof thedata3 iswell aadvanced
Figure4, for exof
the
data
is
well
advanced[15].
Figure4,
for angle,
example, shows the distribution of the azimutal
ample,
showsthe
distributionoftheazimuthal
w, of nuclear conversions at a g energy of 11.8 MeV.
angle,
ω ,ofofthe
nuclearat a γ energy
of
The
ratio
P ⇡ 1 conversions
and P ⇡ 0 distribution
enables
11.8 MeV. The ratio of the P ≈ 1 and P ≈ 0
an almost complete cancellation of the systematic bidistribution enables an almost complete
ases. A (1 + A cos[2(w − w p )]) fit of this distribucancellation of the systematic biases. A (1 +tionyields −a ωvalueof the polarization asymmetry ofAcos[2(ωp)]) fit of this distribution yields a
Avalue= 7.4of±the0.6polarization%, that is lower
than theofvalueof 17%
asymmetryA = 7.4±
predicted
QED thanat thatCarlo
0.6%,that by
is lower
the energy
value of[4].
17%Monte
predicted
simulations
show
that thisof the simulations
asymmetry is
by QED at thatenergy[4].dilution
Monte Carlo
show
that
this
dilutionoftheasymmetryiscompatible with that induced by the single-track resolution at that energy [15].

-energyfrom 1.7 to 74
Monochromaticity
wasMeV.
obtained by collimating the
g beam on axis. In that case, the polarization (fraction
2Time projection chambers are considered alsoenable us to perform polarimetry too [5]. In practice though, thefor Compton telescopes [8] and photoelectric
cross section for a large enough recoil electron momentum is much
telescopes[9, 10].
too small to perform a measurement on a cosmic source [3, 4].

2 Time projection chambers are considered also for Compton
telescopes [8] and photoelectric telescopes [9, 10].

422

NP=100%/NP=0%

1.4

E⌅ = 11.8MeV

1.2

ratio (P=1)/(P=0)[5] Y. Iwata et al., “New polarimeter for high[5] Y. Iwata et al., “New polarimeter for high-energy
energy gamma-rays,” Nucl. Instrum. Meth. A
gamma-rays,” Nucl. Instrum. Meth. A 336, 146
336, 146 (1993).

DATA(1993).

LNA
IMI[6] D.R. Nygren and J. N. Marx, “The Time
[6]Projection
D.R. Nygren
and J. N.Physics
Marx, “TheTime
Chamber”,
Today
31 Projection(1978)
46.Chamber”, Physics Today 31 (1978) 46.

1 + A cos(2(ω - ωp))
A = 7.4 ± 0.6%, ωp = 2.2 ± 2.6o
⇤2 / NDF = 19.1 / 15 = 1.27

[7]
Nucl.Instrum.
Instrum.Meth.
Meth.
[7]D.D.Attie,
Attie,“TPC“TPCreview,”
review,” Nucl.
AA
598,
598,
89
(2009).
89 (2009).

1

RY

0.8

PRE

0.6
0.4
0.2

[8] T. Tanimori et al., “An Electron-Tracking[8] T. Tanimori et al., “An Electron-Tracking Compton
Compton Telescope for a Survey of the Deep
Telescope for a Survey of the Deep Universe by MeV
Universe
by MeV gamma-rays,” Astrophys. J.
gamma-rays,” Astrophys. J. 810, no. 1, 28 (2015)
Figure
4.
The
ratio
of
the
P≈1
and
P≈0
810,
no.
1,
28 (2015) [arXiv:1507.03850 [astroFigure 4: The ratio of the P ⇡ 1 and P ⇡ 0 azimutal[arXiv:1507.03850 [astro-ph.IM]].
azimuthal
distributions
of
11.8
MeV
γ
+
−
ph.IM]].
distributions of 11.8 MeV
g conversion to e e pairs
conversion to e+e− pairs in 2.1 bar argon[9]K.K.Jahoda
Jahodaetetal.,al.,“Polarization“Polarization from
[9]
from Relativistic
RelativisticAsin 2.1
bar argon-isobutane
isobutane
95:5 gas. 95:5 gas.
trophysical X-raY
Sourses:
The PRAXYS
Small ExAstrophysical
X-ray
Sources:
The PRAXYS
plorer Explorer
Observatory”,
American Astronomical
SociSmall
Observatory”,
Americancompatible with that induced by the single-track
ety, AAS Meeting#225,AAS
id.338.40.
Astronomical
Society,
Meeting#225,
id.
resolution at that energy [15].
This work is funded by the French National Re338.40.
[10] “Design improvements and X-ray performance of a
This
work
is
fundedbytheFrenchNational
Research Agency (ANR-13-BS05-0002) and was per- [10] “Design
improvements
and X-ray performancetime projection
chamber polarimeterfor persistent assearch Agency
and wasperformedby using(ANR-13-BS05-0002)
NewSUBARU-GACKO(Gammaofatime
projection
chamberpolarimeter
forInt.
tronomicalsources”,
J.E.
Hill
et
al.,
Proc. SPIE
formed by using NewSUBARU-GACKO (Gamma
Collaboration Hutch of Konan University). It involved
persistentastronomicalsources”,
J.E.
Hill
et
al.,
Soc. Opt. Eng. 9144, 91441N, Montreal(2014)
Collaboration Hutch of Konan University). It
Proc. SPIE Int. Soc. Opt. Eng. 9144, 91441N,
contributions from members of Irfu CEA-Saclay
involved contributions from members of Irfu CEA[11]Montreal(2014)
D. Bernard et al., “HARPO: a TPC as a gammaandof LLR& CNRS/IN2P3
Saclayand ofEcole
LLR PolytechniqueEcole Polytechnique& CNRS/
ray telescope and polarimeter,” Proc. SPIE Int.
(France),and of JASRI/SPring8
and of LASTI
D. Bernard
et al.,“HARPO:
TPC as a
IN2P3 (France),and of JASRI/SPring8
and Uniof [11] Soc.
Opt. Eng.
9144,
91441M, a Montreal(2014)
versityofHyôgo(Japan).
gammaray telescopeand polarimeter,” Proc.
LASTI University of Hyogo (Japan).
[arXiv:1406.4830[astro-ph.IM]].
SPIE
Int.
Soc.
Opt.
Eng. 9144, 91441M,
Onbehalfbehalfof of
Frenchgroupsof theproject,OnthetheFrenchgroupsof theproject,“the[12]Montreal(2014)
K. Horikawa et al.,[arXiv:1406.4830“Measurements for the [astroenergy and“the detector
wouldlike to express
mydetectorteam”, team”,
I wouldI liketo express
my warmest
flux of laser Compton scattering g-ray photons genph.IM]].
warmesttogratitude
to ourJapanese “thecolleagues,“thegratitude
our Japanesecolleagues,
beam team”,
in an electron storage ring: NewSUBARU”,[12] erated
K.Horikawa
et al., “Measurements for the
beamteam”,
without
thededication,
without the dedication, the effectiveness and thethe
efNucl. Instrum. Meth. A 618, 209 (2010).
energy and flux of laser Compton scattering γeffectiveness and the efficiency of whom weficiency of whom we couldn’t have achieved such ageneratedin an electron
couldn’t have achieved such a successful data[13]rayS. photons
Amano etal., “Several-MeV
g-ray storage
generation
successful
and collected
such excellentring:
NewSUBARU”,
Nucl.
Instrum.
Meth. Ataking anddata-taking
collected suchexcellent quality
data. Iin NewSUBARU
by laser
Comptonbackscattering“,
quality618,
209Instrum.
(2010).Meth. A 602, 337 (2009).
a m cdata.
o n v i nI cam
e d convincedt h a t t h ethat
r ethes u l resultst s o f oft hthisis
Nucl.
characterization
of
such
a
high-performance
MeV- [13] S. Amano et al., “Several-MeV γ-ray
characterization of such a high-performance MeV[14] Y. Geerebaert et al., “Measurement of 1.7 toGeVtelescopeand andpolarimeter
will setgroundGeVg-rayγ-raytelescopepolarimeterwill
set
generation in NewSUBARU by laser Compton
74 MeV polarised gamma rays with the HARPO
useon
of board
TPCs aonboardspacea future
space
togroundthe usetoofthe
TPCs
futuremission.
backscattering“,
Nucl. Instrum. Meth. A 602,
TPC,” Proceedings VCI2016, arXiv:1603.06817
mission.
337 (2009).
0

⇥3

⇥2

⇥1

0

1

2

3

ω - ω0 [rad][physics.ins-det], to appear in Nucl. Instrum. Meth.

[14] Y.
et al., “Measurement of 1.7 to 74
A,Geerebaert
doi:10.1016/j.nima.2016.06.031.
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43
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0

0

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Y channel

250

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500

time [30ns bin]

200
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150
100

100

50

50

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100

200

0

300 100

400 200

X channel

200

150

100

100

50

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0

0

0

100

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0
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250

150

100

100

50

50

0

0

100

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500

time [30ns bin]

200

150

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0

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1500

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1000

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3004000

3500

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500

time [30ns bin]

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3500

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Figure 3:of
Four
examplesof gbyraysby the BL01beam
NewSUBARU
beam toline,
Figure 3: Four examples
g raysprovided
the provided
BL01 NewSUBARU
line, converting
an convertinge+ e− pair to an e+ e− pairFigure 3. Four examples of γ rays provided by the BL01 NewSUBARU beam line, converting to an e
into
the 2.1 bar argon-isobutane
gasHARPO
mixtureof theofHARPO
detector.
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event,
the(x,t)
and (y,t) signal
into the 2.1 bar argon-isobutane
mixtureof thedetector.
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each
event,
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(x,t)
and
(y,t)
signal+e− pair into thegas
2.1barargon-isobutane
gas mixture
thedetector.
each
event,
the(x,“maps”
areshown.
The
vertical
lines
at
the
⇡
90
and
⇡
410
time
bins
show
the
event
time
t
and
the
arrival“maps” are shown.
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lines
at
the
⇡
90
and
⇡
410
time
bins
show
the
event
time
t
0 bins show the 0 and the arrivalt) and (y, t) signal “maps” are shown. The vertical lines at the ≈ 90 and ≈ 410 time
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MeV
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downwards
in
the
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are directed
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the (x,t)
map, while the incident
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photonwas
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directedhorizontally,horizontally, coming
coming fromfrom thethe “left”.
“left”. The
11.8
MeV eventshows
aa strongstrong localized energy
photon
The
11.8
MeV
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shows
photon was directed horizontally, coming from the “left”. The 11.8 MeV event shows a strong localized energy
localized energy deposit on the “upper leg”, due to a low-energy δ -ray.
depositon theleg”, due toa low-energy d -ray.
deposit on the “upperleg”,
due“upper
to a low-energy
d -ray.

4444Measurements of nuclear resonance fluorescence on 52Cr
with a linearly polarized photon beam at BL01
Toshiyuki Shizuma1, T. Hayakawa1, F. Minato2, I. Daito3, H. Ohgaki3, S. Miyamoto4
1
National Institutes for Quantum and Radiological Science and Technology
2
Japan Atomic Energy Agency
3
Kyoto University
4
LASTI, University of Hyogo

Abstract
Electromagnetic dipole transitions in 52Cr were measured via nuclear resonance fluorescence with alinearly polarized photon beam generated by laser Compton scattering between laser light and highenergy electrons. More than 40 transitions were observed at excitation energy between 7.5 and 12
MeV in 52Cr. Parity quantum numbers of the excited states were determined by comparison of
azimuthal intensity asymmetry of scattered  rays with respect to the polarization plane of theincident photon beam. Strength distribution of the dipole transitions was obtained from the measured
intensity of the scattered  rays. A total ground state decay width of 35.6(1.1) eV was obtained atenergy region between 7.5 and 12 MeV.
Introduction
Electric dipole (E1) and magnetic dipole (M1)
excitations at low excitation energy are
fundamental excitation modes of atomic nuclei.
The observation of the E1 and M1 transitions
provides information on the collective and singleparticle motion such as pygmy E1 resonance(PDR) [1] and spin-flip M1 resonance [2]. For
example, the M1 resonance is related to the spin
dependent part of the nuclear excitation [3].
Nuclei in the vicinity of the closed � � � �
28 shells such as chromium, iron, and nickel
exhibit one of the most favorable regions forobserving both the E1 and M1 transitions at low
excitation energy. However, it is difficult todistinguish E1 and M1 transitions in nuclear
resonance fluorescence (NRF) measurementswith unpolarized photon beam such as
bremsstrahlung radiation, since both E1 and M1
transitions have same angular distribution. On theother hand, by using a linearly polarized photon
beam it is possible to determine whether thetransition type is E1 or M1, since E1 transitions
have different angular distribution from M1
transitions with respect to the polarization of theincident photon beam. In order to measure the E1
and M1 strength distribution in 52Cr, we havecarried NRF measurements with a linearlypolarized
photonbeam
deliveredat
NewSUBARU.
Experiments and Results
A quasi-monoenergetic, linearly polarized
photon beam was generated in backward
Compton scattering of laser light with high energy
electrons circulated in the NewSUBARU electron
storage ring. A Q-switch Nd:YVO4 laser with awavelength of 1064 nm operated at a frequency of

20 kHz was used for the incident laser photons.
The energy of electrons was chosen to be 683, 708,
731, 756, 792, and 828 MeV to generate quasimonoenergetic photon beams with the maximum
energy of 8.2, 8.8, 9.4, 10, 11, and 12 MeV,
respectively. A 10 cm thick Pb collimator with a
3-mm aperture was used to produce a quasimonoenergetic photon beam with �� ⁄� � ��.
The average photon flux was 6.2x105 photons/s
which was measured by an 8”x10” NaI(Tl)scintillation detector. The target was a natural
chromium with a diameter of 1 cm and a length of
3cm. Two high-purity Ge detectors withefficiencies of 120% and 140% relative to a 3”x3”
NaI scintillation detector were used to observe
scattered  rays from the target. The 120% (140%)
Ge detector was placed horizontally (vertically) ata scattering angle  of 90° to measure intensity
asymmetry of scattered  rays with respect to thepolarization plane of the incident photon
beam. The energy distribution of the incident
photon beam was measured by a 3.5”x4” LaBr3
detector. A Monte Carlo simulation code EGS-5[4] was used to analyze the response of the LaBr3
detector for extraction of the energy distributionof the incident photon beam.
Figure 1 shows a typical energy spectrum of
scattered  rays obtained at polar and azimuthal
angles of ��, �� � �90°, 0°� and �90°, 90°�from the measurements with the maximum
photon beam energy of 8.2 MeV. In the upper(lower) panel M1 (E1) transitions are shown.
The intensity asymmetry of the scatteredrays with respect to the polarization plane of theincident photon beam can be used to deducetransition multipolarity, i.e., parity quantum

45References[1] A. Tonchev et al., Phys. Rev. Lett. 104,
072501 (2010).
[2] K. Heyde et al., Rev. Mod. Phys. 82, 2365
(2000).
[3] A. Richter, Prog. Part. Nucl. Phys. 34, 261(1995).
[4] W.R. Nelson et al., SLAC National
Accelerator Laboratory, Report No. SLAC-R-

35.6(1.1) eV was obtained at energy region
between 7.5 and 12 MeV.
30

parallel=00
perpendicular60 = 90Counts / 2 keV

20
10

40
20
0
6500

7000

7500

8000

8500

Energy (keV)

Figure 1 Typical NRF -ray spectra observed at
the polar and azimuthal angles of ��, �� �
�90°, 0°� and �90°, 90°� are shown in upper
panel and lower panel, respectively. In addition to
the NRF  rays, peaks associated with single anddouble escapes are seen.

M1

Asymmetry

numbers of resonant states. The azimuthal angular
distribution of dipole transitions is known as
3W�θ, ϕ� � W�θ� � �� � cos � θ�cosϕ4where θ is the scattering angle between theincoming and scattered photons and  is theazimuthal angle defined by the polarization plane
and the reaction plane. W�θ� is the angularcorrelation function for unpolarized radiation [5].
Here, the minus (plus) sign is for E1 (M1)transitions.
The analyzing power for parity determination
is defined by using the azimuthal angular
distribution of ��90°, 0°� and ��90°, 90°� as��90°, 0°� � ��90°, 90°�����90°, 0°� � ��90°, 90°�The analyzing power equals to �� for M1
transitions and �� for E1 transitions under the
100% linear polarization of the incident photon
beam. On the other hand, the measured intensity
asymmetry is given by�∥ � ��� �����∥ � ��
where �∥ ( �� ) is the measured intensity of
scattered  rays detected at θ � 90° in the plane
parallel (perpendicular) to the polarization plane.
Here, q is the measurement sensitivity of thedetection system which is estimated to be 0.8 forthe present case by using the Monte Carlosimulation code. Therefore, the azimuthal
intensity asymmetry is expected to be +0.8 for M1
transitions and -0.8 for E1 transitions. Figure 2
shows the measured intensity asymmetry for the
scattered  rays. The data are clearly separated on
the multiporalities (E1 or M1) of the transitions.
The energy integrated scattering cross sections
�� were deduced from the measured intensity ofthe transtions to the ground states. Here, �� isdefined using the partial decay width of theground state transition as�� � � ��� � Γ��
�� �
�
�
Γ
��� � � �
where �, E, and  are the spin, energy, and total
decay width of the excited state, respectively, and�� is the spin of the groud state. From the present
measurement, a total ground state decay width of

0.5
0
−0.5
−1
−1.5

E1
7.0

8.0

9.0

10.0

11.0

12.0

Excitation energy (MeV)

Figure 2 Azimuthal intensity asymmetry obtainedfor M1 (closed circle) and E1 (open circles)
transitions in 52Cr. The experimental sensitivity q(=0.8) deduced from the numerical calculation isshown with dashed lines.
265 (1985).
[5] L.W. Fagg and S.S. Hanna, Rev. Mod. Phys.
31, 711 (1959).

46

Azimuthal anisotropy of neutrons in
56Fe(polarized , n)55Fe reaction at BL01
T. Hayakawa1, T. Shizuma1, S. Miyamoto2, S. Amano2, A. Takemoto2, M. Yamaguchi2, and K. Horikawa2,
H. Akimune3, S. Chiba4, K. Ogata5 and M. Fujiwara5
1
National Institute for Quantum and Radiological Science and Technology
2
LASTI, University of Hyogo
3
Konan University
4
Tokyo Institute of Technology
5
Research Center for Nuclear Physics (RCNP), Osaka University
Abstract
We have measured the azimuthal anisotropy of neutron yields emitted from the 56Fe( n)55Fe reaction
with a linearly polarized -ray beam generated by laser Compton scattering at the beam line of BL01 in
NewSUBARU. The neutron yields have been measured as a function of the azimuthal angle φ of thelinear polarization plane of the  ray beam at the polar angle of 90◦. The azimuthal anisotropy of the neutrons
measured at �=0◦, 10◦, 25◦, 45◦, 60◦, 70◦, and 90◦ has been well reproduced by a function of a + bcos(2�)
predicted by Agodi in 1957.

Introduction
In 1957, Agodi predicted theoreticallythat when a nucleus is excited via dipole
transitions with linearly polarized -rays,
the azimuthal angle distribution of
nucleons emitted from (, n) and (, p)reactions at the polar angle =90◦ should
follow a simple function of a + b cos(2φ),
where � is the azimuthal angel [1].
Because there was no established method
to generate 100% linear polarized energy
tunable -ray beam, Agodi’s prediction has
not been examined for nuclei in a widemass region. Horikawa et al. have verified
for the first time this prediction bymeasuring neutrons from Au, I, and Cu [2]using linear polarized laser Compton
scattering -ray beams at BL01 in
NewSUBARU. However, the azimuthal
angle distributions were measured only in
30 degree steps. Unfortunately, since thefunction of cos(2�) has the symmetry
against �, only a few measured points
give difference values. Therefore, in thisstudy we measure neutron yields from the56Fe(polarized , n)55Fe reaction at sevenangles of �=0◦, 10◦, 25◦, 45◦, 60◦, 70◦, andto verify in further detail the90◦
azimuthal angle distribution predicted by
Agodi [3].

provided from a Q-switch Nd:YVO4 laser. The
maximum energy of the generated photon beam
was 16.7 MeV, which was determined by theelectron energy and the laser wavelength. Theenergy of electrons stored in NewSUBARU was
974 MeV. The wavelength of the laser was 1064
nm. In contrast, the lowest energy of the LCS
beam was mainly determined by the collimatorsize. A collimator with a diameter of 3 mm wasset before the target position. The energy spreadof the rays is about 3 MeV. The diameter of theincident -ray beam was about 3 mm at the target
position. The storage ring was operated by asingle bunch mode with a repetition rate of 2.5
MHz to generate only one -ray pulse by one
laser pulse. The time widths of the electron bunch
and the laser pulse were 60 ps and 8 ns,
respectively. The laser power was 3.8 W and theelectron current was about 20 mA. The evaluatedflux of the photons was (1-2)106 photons/s in anenergy range from 14 MeV to 16.7 MeV.
Neutrons were generated by the photoninduced reaction on 56Fe (see Fig. 1). The
neutrons were measured using the time-of-fight(TOF) method. The target was located inside of
the irradiation room with a concrete shield with athickness of 540 mm. Neutrons were led to theoutside of the irradiation room through a holewith a diameter of 80 mm. The distance between
the target and the detector was 970 mm. Neutronsand photons were measured using a plastic
scintillator with a size of �50 mm  30 mm witha 60-mm diameter photomultiplier. This detector
was located at the polar angle of =90◦ outside of
the irradiation room. A 2-mm thickness leadExperiments and Results
The LCS ray beam was generated by theCompton scattering of high energy electrons
stored in NewSUBARU with laser photons

47

shield was set in front of the detector to absorb
low photons. However, high energy γ-rays
scattered from the target were also observed. A
time-to-amplitude converter (TAC) was used tomeasure the time interval between a start pulse
from the detector and a stop pulse from theelectron storage ring. The TAC signals wererecorded using a multi-channel analyzer (MCA).
A natural iron target with a size of φ10 mm ×
50 mm was used. Since the isotopic abundance of
56Fe is 91.7%, we assume that the neutron
anisotropy from 56Fe is dominated in thefollowing discussion.

7/27/25/21/23/2-

Counts per channel

 rays

104
10 3
102

Neutrons

101
100

600

750

700

650

Time [ns]Figure 2 Typical Time-of-Flight spectrum. The
neutrons and -rays emitted from the irontarget are clearly separated.

Max Energy
16.7 MeV
1- (1+)

70

1408
1316
931
411
0

60

Sn
9298 keV

55 Fe
E1 (M1)
Exitation

0+

0

50

Neutron yields

NeutronEmission

105

40
30
20
10

56 Fe

Figure1
Schematic
figureforphotodisintegration reactions on 56Fe. Excitedstates with low spin states in 56Fe are populatedby the absorption of a photon, and subsequently
these excited states decays away to the residual
nucleus 55Fe by the emission of a neutron.

0
0

10

20

30

40

50

60

70

80

90

Angle [Degree]
Figure 3 Neutron yields as a function of the angle
between the detector and the plain of the linear
polarization. The dashed line is derived by 2fitting.
plot a neutron yields as a function of theazimuthal angle, ϕ, between the detector and theplain of the linear polarization of the incident
gamma-ray beam. These yields can be
reproduced well by the function of a + b cos(2ϕ),
which was predicted by Agodi [3].

The neutron anisotropy was measured bychanging the angle of the linear polarization
plane of the incident LCS ray beam at the angles
of φ=0◦,10◦, 25◦, 45◦, 60◦, 70◦, and 90◦, where�=0◦ was defined as the electric wave being in
the plane of the detector. The linear polarization
plane angle of the LCS beam was determined bymeasuring the polarization plane angle of thelaser since the polarization of the laser wastransferred directly to the LCS -ray.
Figure 2 shows a typical TOF spectrum
measured by the plastic scintillator. A broad peakfor neutrons and a sharp peak for gamma-rays areobserved. These two peaks are clearly separated
by the TOF method. The background originatedfrom natural radioactivities and cosmic-rays is
low compared with the neutron signal. Next, weReferences[1] A. Agodi, Il Nuovo Cimento, 5(1), 21 (1957).
[2] K. Horikawa et al., Phys. Lett. B, 737, 109(2014).
[3] T. Hayakawa et al., Phys. Rev. C 93, 044313(2016).

48

The film modification of Si-containing hydrogenated DLC
films by the soft X-ray irradiation
Shotaro TANAKA1, Ryo IMAI1, Takayuki HASEGAWA2 and Kazuhiro KANDA1
1. LASTI, University of Hyogo
2. Synchrotron Analysis L. L. C.
Abstract
The film modification of Si-containing diamond-like carbon (Si-DLC) films by the exposure tosynchrotron radiation (SR) in the soft X-ray region was studied by near-edge X-ray absorption finestructure (NEXAFS) spectroscopy using SR. We found that Si oxidization layer was formed atsurface of Si-DLC and this oxidization layer was deoxidized by the additional exposure to soft Xray. Because of absorption of soft X-ray by Si oxidization layer, the Si oxidization layer protect SiDLC films from soft X-ray exposure, and desorption of hydrogen was suppressed.

Introduction
Diamond-like carbon (DLC) films have various
useful properties such as high hardness, a low
friction coefficient, high abrasion quality, a gas
barrier, chemical inertness and surface lubrication.
Because of these characteristics, DLC films were
utilized as coating materials on automobile parts,
hard disks, artificial blood vessels, edge tools andfood containers. In addition, DLC films are
expected to be used in outer space as a lubrication
instead of oil, which cannot be used in spacebecause it freezes in vacuums [1, 2]. But, it has beenreported that hydrogenated DLC (H-DLC) films
were caused desorption of hydrogen due to soft Xray exposure [3].
Hetero elements such as Si, Ti and W were
improved by several properties of DLC films suchas heat-resisting property, and adhesion. We foundout that desorption of hydrogen was suppressed in
the soft X-ray exposure to Si doped DLC films. But
sp2/(sp2+sp3) ratio of C atom estimated from
NEXAFS spectra was increased and film volume
was decreased by soft X-ray exposure. These results
are same with the results of irradiation experiments
for none doped H-DLC films. Clarification of theeffect of soft X-ray exposure on DLC films isimportant to ensure that DLC films are used in outerspace safely. In this study, we investigated themodification of Si-DLC films by soft X-ray
exposure by the measurement of Si-K edge
NEXAFS spectra of Si-DLC films.

Experiments
500-nm-thick Si-DLC films were deposited on
Si wafers by using a plasma-enhanced CVD method.
The content of H, C and Si of Si-DLC films were
≈40 at.％, ≈40 at.％ and ≈20 at.％ respectively.
There were estimated from the combination of
Rutherford backscattering spectrometry (RBS) andelastic recoil detection analysis (ERDA) techniques.
The soft X-ray irradiation of the Si-DLC films
was carried out at BL06. The SR at the BL06
irradiation chamber had a continuous spectrum
from IR to soft X-rays, lower than 1000 eV. This
include 110 eV and 300 eV, which is the ionizationenergy of a silicon L shell and a carbon K shell,
respectively. During this experiment, the electronenergy of NewSUBARU storage ring was 1.0 GeV.
The BL06 sample stage was room temperature andthe pressure in the chamber was the order of 10-5 Pa.
An SR dose [mA･h] was derived from the productof the ring current [mA] and exposure time [h].
Si-K edge NEXAFS spectra were measured bytotal electron yield (TEY) method at BL05A of the
NewSUBARU. This measurement enabled us toknow information on the local structure near surface
of sample. The soft X-ray exposure to sample
carried out at magic angle (54.7°) with respect tothe surface of the sample. The measured energy
range in the experiment was 1810-1890 eV of Si-K
edge.

49

Result and discussion
Figure 1 shows Si-K edge NEXAFS spectra of
Si-DLC films exposed to the soft X-ray, that of the
Si-DLC film before exposure and that of the SiO2
powder for comparing the peak of Si-DLC films.
The peak of 1846.8 eV was appeared at 80 mA･hsoft X-ray dose. This peak derived from SiO2. This
result means that Si in Si-DLC films was oxidized
by soft X-ray exposure under existence of oxygen.
However, intensity of the peak of 1846.8 eV
decreased at 1500 mA･h dose. Figure 2 shows Si-K
edge NEXAFS spectra around 1846.8 eV. The peakof 1846.8 eV drastically increased until 800 mA･hdose. However, at 1000 mA･h dose (pink line), theintensity of peak decreased. Moreover, the intensityof peak decreased sharply at 1500 mA･h dose. On
the other hand, the intensity of the energy range
about 1843-1846 eV increased. This energy range
derived from deoxidization of SiO2 [4]. These
results mean that the Si oxidization layer wasformed at 200 mA･h dose. It is considered the Si
was oxidized by residual oxygen at vacuum
chamber. The formed Si oxidization layer was
deoxidized by the additional exposure to soft X-ray. It
is considered that hydrogen in Si-DLC films wasdesorbed by soft X-ray exposure at the dose range of
0-200 mA ･ h. Beyond 200 mA ･ h, Because ofabsorption of soft X-ray by Si oxidization layer, soft
X-ray was not reached bulk of Si-DLC, anddesorption of hydrogen was suppressed. Figure 3
shows result of dependence of soft X-ray irradiationof volume change. Comparing these results with theresults of volume change, the volume wasdrastically decreased by desorption of hydrogenprocess at the dose range of 0-200 mA･h. Beyond
200 mA･h, the Si oxidization layer protect Si-DLC
films from soft X-ray exposure, and desorption ofhydrogen was suppressed. As a result degree ofvolume decrease was slowly decrease. However the
Si oxidization layer was deoxidized in the region
more than 800 mA･h, degree of volume change was
not changed. It is considered that deoxidization of
Si oxidization layer is not affected the durability
against X-ray exposure. Oxidization of Si in SiDLC caused by the irradiation of atomic oxygen
was reported [5]. Thus, it is considered that these
phenomena can be observed at outer space.
Therefore, it was found that the Si-DLC films have
durable against space environment such as soft Xray.

Conclusion
The film modification of Si-DLC films by the soft
X-ray exposure was investigated by the measurementof Si-K edge NEXAFS spectra. Si oxidization layer
was formed at surface of Si-DLC films by soft X-ray
exposure under existence of oxygen. The Si
oxidization layer was deoxidized by the exposure tosoft X-ray. In addition, it was founded the Si
oxidization layer protect Si-DLC films from soft X-ray
exposure because of soft X-ray was desorbed by the Si
oxidization layer. Therefore, Si-DLC films have highdurable against space environment such as soft X-ray
and atomic oxygen.
Reference[1] C. Donnet et al., Surf. Coat. Technol. 120(1999)548.
[2] C. Donnet et al., Tribology of Diamond-like
Carbon, Springer, 2008.
[3] R. Imai et al., Diamond. Relat. Matel.
44(2014)8-10.
[4] R. Sammynaiken et al., J. Appl. Phys. 92(2002) 3000.
[5] K. Kidena et al., Trans. Mat. Res. Soc. Japan40 (2015) 363.

50

500 mA·h

Normalized Absorption [a.u.]

1846.8 eV

200 mA·h

Figure 2. Si-K edge NEXAFS spectra

SiO 2

Normalized Absorption [a.u.]

1500 mA·h
1000 mA·h
800 mA·h

100 mA·h

1835

1840
1845
Energy [eV]1850

around 1846.8 eV of Si-DLC films before
and after soft X-ray exposure.

80 mA·h

100
80
段差 /nm0 mA·h1830 1850 1870 1890
Energy [eV]

0 mA·h80 mA·h
100 mA·h
200 mA·h
500 mA·h
800 mA·h1000 mA·h
1500 mA·h

60
40

Figure 1. Si-K edge NEXAFS spectra of20

Si-DLC films before and after soft X-ray

0

exposure and SiO2 powder. The blue line
is 1846.8 eV.

0

1000

2000
3000
Dose量 /mA·h

4000

Figure 3. Dependence of soft X-ray irradiationof volume change.

51

Surface Modification Processes of Highly HydrogenatedDiamond-Like Carbon Thin Films by the Soft X-ray Irradiation
1

Kazuhiro Kanda1, Ryo Imai1, Keiji Komatsu2, Hidetoshi Saitoh2
LASTI, University of Hyogo, 2 Nagaoka University of Technology

Abstract
Synchrotron radiation process of a hydrogenated diamond-like carbon (H-DLC) film wasinvestigated by the exposure of H-DLC films to white soft X-ray lower than 1000 eV. The desorbed
species from the surface of H-DLC film by irradiation of soft X-ray and its dose dependence were
measured using quadrupole mass spectrometer. The dose dependency of thickness and density of HDLC film were discussed by the measurement of X-ray reflection. The film modification of H-DLC
film by the SR exposure was confirmed to occur due to the desorption of hydrogen molecule from
H-DLC film in the dose range of 0 - 200 mA･h.
Introduction
Diamond-like carbon (DLC) film isamorphous carbon film, which contains sp3
hybridized carbon corresponding to a diamondhybridized
carbonstructureandsp2
corresponding to a graphite structure. In addition,
DLC film usually contains a certain amount ofhydrogen. The superlubricity of DLC film, along
its low friction coefficient, high hardness,chemical inert, and high wear and corrosion
resistance, make it one of the most promisingcoatings for applications, such as cutting tools,
automobile parts, molds, computer hard disks,
optical devices, food containers, and artificial
blood vessels. Recently DLC film wasconsidered to use as a lubrication material inspace from its superlubricity. Oils and fats, which
are used as lubricant materials on the ground,cannot be used in outer space, because theyevaporated and froze in a vacuum. Hydrogenated
DLC (H-DLC) film with a hydrogen content
greater than 40 at.% can be expected to use as alubrication material in space because it provides
ultra-low friction (friction coefficient less than
0.001), even under vacuum conditions [1,2]. On
the other hand, in the outer space, environmental
tolerances unlike ground, such as ultra-highvacuum, variation in temperature from a hightemperature to low temperature, collision withionic particles and neutral atoms, and soft X-ray
irradiation, are required. It has been consideredthat the DLC film generally had very strong
tolerance for a soft X-ray [3]. However, ourgroup has recently reported that soft X-ray
exposure on H-DLC films leads to surface
modification; Soft X-ray irradiation against
hydrogen-rich DLC films caused desorption ofhydrogen from film and film volume change [4]and rise of hardness [5]. Still, the modification
processes causing by soft X-ray exposure on HDLC films are not yet fully understood.
In order to use hydrogenated DLC films

safely in space, it is necessary to clarify the
influence of soft X-ray on film properties and rateof the deterioration of H-DLC film by the soft-X
ray. In the present work, for the purpose to grasp
the modification processes by soft X-ray
exposure on H-DLC films, we measured thedesorbed species from the surface of H-DLC film
by irradiation of soft X-ray and its dose
dependence using quadrupole mass spectrometer(QMS). In addition, dose dependences of film
density and thickness were estimated by themeasurement of X-ray reflection (XRR).
Material and methods
H-DLC films were deposited on Si wafers byusing an amplitude-modulated RF plasmaenhanced CVD method. (Nippon ITF Co.) Thismethod enables the deposition of DLC films
containing a lot of hydrogen. The desired valueof film thickness was 200-nm-thick. The
hydrogen content of H-DLC films was estimatedto be 50 at.% by using the combination of
Rutherford backscattering spectrometry (RBS)
and elastic recoil detection analysis (ERDA)
techniques [5].
The SR irradiation of the H-DLC films was
carried out at BL06 of the NewSUBARU
synchrotron facility. The experimental apparatus
at BL06 are described in detail in refs. [6,7]. The
light source of BL06 was bending magnet. The
SR extracted from a bending magnet was
introduced to sample stage as straight light via apair of mirror. The SR at the BL06 sample stage
had a continuous spectrum from IR to soft X-rays,
lower than 1 keV. This includes 300 eV, which is
the ionization energy of a carbon K shell. During
this experiment, the electron energy of the
NewSUBARU ring was 1.0 GeV and the ring
current was 300 mA in the top-up mode. Except
the detection of desorbed species using
quadrupole mass spectrometer, the SR was

52

irradiated to a sample surface perpendicularly.
An SR dose [mA･h] is derived from the productof the ring current [mA] and exposure time [h].
In the present study, the H-DLC films were
exposed to soft X-ray in the dose region to 3000
mA･h. During the exposure of the H-DLC films
to soft X-ray, the pressure in the irradiationchamber was the order of 10-5 Pa and thetemperature of a sample stage was confirmed to
be room temperature using a thermocouple. Afterthe SR exposure, the modified H-DLC films were
kept in the dry box.

respectively. These are back ground species, whichwere not removed by above treatment, and/or
species, which adhered to the surface of the H-DLC
film. In tense peak at mass number 2 showed thathydrogen molecules and/or hydrogen molecule ionswere desorbed from the surface of H-DLC film by
SR exposure. Peak at mass number 1 is due tohydrogen ion and/or hydrogen atom, which might
directly come out of a H-DLC film; and made bydecoupling of hydrogen molecules in the QMS is
possible. It is a noteworthy fact that the species thatcarbon coupled with hydrogen, such as CH＋ (massnumber, 13), CH2 ＋ (mass number, 14), C2H2 ＋(mass number 26), and etc. were not observed. In
other words, desorption of carbon, namely, etching
was very slower than desorption of hydrogen.
Next we studied dose dependence of quantity ofdesorbed species. In this experiment, we usedcommercial DLC film deposited with ion plating
method (Nanotec) for a reference as a representative
mark of typical DLC film. The hydrogen content ofion-plating DLC (IP-DLC) film was 20 %estimated by using ERDA/RBS. Fig. 2 showed thedose dependence of most intense peak at mass
number, 2.

Result and Discussion
Dose dependences of the desorbed species
from H-DLC film surface by the irradiation ofsoft X-ray was measured using a QMS (Anelva
Co., Q-M400QA-M) equipped at irradiationchamber of BL06. A detectable mass range wasfrom 1 to 400, and mass resolution, M/ΔM≧2M.
The QMS was arranged perpendicular to theadvancing direction of soft X-ray beam. In thismeasurement, an incident soft X-ray beam wasintroduced to a sample at 45 with respect to thesurface normal. The desorbed species from thesample were detected with a QMS arranged at
45 with respect to the surface normal of thesample in the opposite direction of the incident
beam. Detected signals with QMS wereconsidered to include not only desorbed species
from sample DLC films, but residual gas species
in the irradiation chamber and substrate Si wafer.
Therefore, we measured the mass spectrum in the
SR exposure to Si wafer without the depositionof DLC film as back-ground, and we subtracted
these values from the measured mass spectrum in
the SR exposure to H-DLC film. Mass spectrum
just after an SR irradiation start to H-DLC film,
which was obtained by such treatment describedabove, was showed in Fig. 1. In the mass range
more than 60, the peak was not observed.

Fig.2 SR dose dependence of H2+ species (massnumber = 2) from H-DLC film and IP-DLC film.
A large quantity of hydrogen is emitted from the HDLC film at the same time to start irradiation of soft Xray. Quantity of desorbed hydrogen decreased steadily
with increase of SR dose and became approximately
constant with a very small value in the dose range morethan 200 mA ･ h. On the other hand, desorption ofhydrogen was hardly observed even if IP-DLC film
was expose to soft X-ray. That to say, it was confirmedthat hydrogen was not desorbed in the exposure of the
DLC film with the hydrogen content less than a certain
value. From these results, H-DLC film can be modified
due to desorption of hydrogen by the soft X-ray
exposure, while IP-DLC film has high tolerance against
soft X-ray.
We performed the measurement of the X-ray
reflection (XRR) to obtain a film thickness anddensity of the H-DLC film. The X-ray reflection wasmeasured with XRR apparatus (Mac science,
M03XHF MXP3). Fig. 3 showed the exposure dose

Fig. 1 Mass spectrum of desorbed species from
H-DLC film by the irradiation of SR just after
start.
Peaks in Fig. 1 at mass number 18 and 28 wereascribable to water molecule and nitrogen molecule,

53

200

1.8
Density [g/cm 3]

Film Thickness [nm]dependence of the film thickness estimated from
XRR study.
as-grown
irradiated

180
160
140
120
100

1.6
1.4
1.2

0

1000
2000
SR dose [mA·h]

3000

Fig. 3 Dose dependence of thickness of H-DLC
film estimated by the measurement of XRR.

as-grown
irradiated

0

1000
2000
SR dose [mA·h]

3000

The film thickness at the time of non-irradiation was
according to film formation condition in 200 nm.
Film thickness suddenly decreased from 200 nm to145 nm by SR exposure in the dose range of 0 - 200
mA･h. In the dose range more than 200 mA･h, film
thickness decreased gently and maintained theconstant in 130 nm.
Fig. 4 showed the dose dependence of film density
on the basis of XRR measurement.

Conclusion
In the irradiation of soft X-ray against H-DLC film,
desorption of hydrogen from H-DLC film, decrease offilm thickness, and increase of film density was
occurred in the dose range of 0 - 200 mA･h. These
dose dependences were accord with that of hydrogencontent in the film which was estimated from
ERDA/RBS technique in ref. [5]. From these results,
modification of H-DLC film by the soft X-ray begins
with desorption of hydrogen molecules from H-DLC
film by the absorption of soft X-ray. It was confirmedthat desorption of hydrogen caused decrease of film
volume and increase of density, and other film
properties.

The density of H-DLC film at the time of nonirradiation was 1.25 g/cm3. Density of diamond andgraphite are 3.51 g/cm3 and 2.26 g/cm3. Density of
DLC films almost populated in the range of 1.7-2.3
g/cm3, and that of H-DLC film used in the present study,
1.25 g/cm3 was very small. Density of H-DLC film
before SR exposure, 1.25 g/cm3 increased drastically to
1.40 g/cm3 by after SR exposure with the 200 mA･hdose. In the dose range more than 200 mA･h, film
density increased gradually and became constant, 1.60
g/cm3 in the dose more than 2000 mA･h. From theseFig. 4it Dosedependencethat
of decreasedensity of
results,
was confirmed
in H-DLC
the film
film
estimatedbythemeasurementof
XRR.
thickness and increase in the film density of H-DLC
film by irradiation of soft X-ray.

References[1] C. Donnet et al., Tribology of Diamond-like Carbon,
Springer (2008).
[2] C. Donnet et al., Surf. Coat. Technol. 68-69 (1994)
626.
[3] H. Kyuragi et al., Appl. Phys. Lett. 50 (1987) 1254.
[4] K. Kanda et al., Jpn. J. Appl. Phys. 50 (2011)055801.
[5] R. Imai et al., Diamond Relat. Matter. 44 (2014) 810.
[6] K. Kanda et al., Jpn. J. Appl. Phys., 42 (2003) 39833985.
[7] Y. Kato et al., Jpn. J. Appl. Phys., 43, (2004) 39383940.

54

Refractive-index modifications in Silica-Based Films
by Undurator Radiation with a multilayer spectrometer
K. Moriwaki, G.Kimura, Graduate School of Eng., Kobe Univ.,
K.Kanda, and S.Matsui, LASTI/Univ. Hyogo

Abstract
Undurator radiation (UR) by the NewSUBARU (BL7A) is used for silica-based films
modifications for applications of optical devices like waveguides. UR with or without a multilayer
spectrometer is used for the samples, and the observed effects are compared. The modification layers
are separated in two parts of the shallow and strong one and the relatively deep and moderate one
without the spectrometer. The thin layers with less than 5 nm thickness from the surface show strong
reduction and high refractive index changes on the order of 10-2 depending on the UR energy. With
the spectrometer, the surface reduction layer is not observed after the UR radiation, although therelatively deep and moderately modified layer is observed. The difference between the samples
irradiated with and without the spectrometer may be caused by the irradiation intensity or a sample
temperature effect.
Introduction
Synchrotron radiation (SR) and undurator
radiation (UR) are used for radiation-induced
refractive index changes in silica-based glass for
optical devices like optical waveguides1,2). UR isa very useful tool for the materials modifications,because it can select a useful wavelength, havingvery high intensity. UR with a multilayer
spectrometer would be more useful for the
purpose because it has high intensity and themost suitable wavelength can be selected withouthigher order ones. In this report, modification
effects are compared with or without the
spectrometer.

spectrometer1,2). The two-layer structures havelarge refractive-index in the very thin surface,and have relatively low refractive-index layer inthe underlying part.
For the surface layer in the two-layer structures,it was found that the refractive-index changes are
increased by making the UR irradiation
wavelength longer. By the results of XPS
measurements, Si-Si bonds in the shallow surface
layer less than 4nm thickness appeared, thatmeans surface reduction. A correlation between
an amount of the Si-Si bonds and the refractiveindex changes were also found. By the results of
optical absorbance measurements, defects were
found to be generated by the UR irradiation. The
Si-Si bonds is a major cause of the refractive
index changes in the sample. Other defects arealso suggested to be a cause of the refractiveindex changes in both the shallow surface and theunderlying layer. The refractive indices werereduced drastically by removing the surface
reduction layer, but they still remain at certain
level (10-3) which can be applied for some opticaldevices2).
Figure2 shows that the surface reduction layer
is not observed in the sample irradiated by URwith the spectrometer, as compared in the sample
irradiated without the spectrometer. There is aclear difference between the two samples. The
samples show also no reduction evidence asshown in Fig.3, by increasing irradiation-dose up
to by 4 time as much as the one in Fig.2. The
results in Fig.3 might mean that causes of the
reduction are not only by the higher irradiation
intensity but by the sample temperature effect,
because the sample temperature is drasticallydecreased on the samples irradiated by UR withthe spectrometer.

Experiments and Results
Thermally grown SiO2 films on Si substrates
and fused quartz substrates were used for the UR
irradiation. UR with the first-peak energy ranging
from 20 to 110eV is used without the
spectrometer, and more than 80eV is used withthe spectrometer. Irradiated samples werecharacterized by XPS (X-ray Photoelectron
Spectroscopy), optical absorption spectroscopy,
and refractive index measurements.
Figure 1 shows two modification layer modelfor the samples irradiated by UR without theHigh n layer
SiO2

Low n layer

Si substrate

FIG.1 Two modification-layers irradiated by URwith a peak energy from 20 to 110eV without the
spectrometer. Each layers show higher (10-2-10-1)
and lower (10-2) refractive-index changes,
respectively.

55

Intensity (arb.unit)

Further investigations are needed for themeasurements because of the scattered results in
Fig.4.
The refractive index changes may be caused by
defects in the irradiated samples, as appeared in
Fig.5 and Fig.6. By using the spectrometer, theabsorbance for the irradiated samples isdecreased from the one without the spectrometer,
but still show the certain level (Fig.5). The
absorbance data were changed by the irradiatedpeak-energies as in Fig.6, but its reproducibility
is not clear yet.

500mA*hour without multilayer filter
500mA*hour with multilayer filter

O
O

Si

O
O

Si-Si

114 112 110 108 106 104 102 100 98

Binding Energy (eV)

96

94

0.05

without the spectrometerwith the spectrometer0.04

absorbanceIntensity (arb.unit)

Fig2. XPS spectra of Si 2p peaks for UR
irradiated samples with an energy of 80eVwith and without a multilayer filter. Twopeaks are those of SiO2 and Si-Si bond2).
500mA*hour
1000mA*hour
1500mA*hour
2000mA*hour

0.0380eV 500mA*hour

0.02
0.01
0.00
200

114 112 110 108 106 104 102 100 98

Binding Energy (eV)

96

250

300

wavelength (nm)350

Fig5. Optical absorbance for samples
irradiated by UR with and without the
spectrometer.

94

Fig3. XPS spectra of Si 2p peaks for UR
irradiated samples with the spectrometer byincreasing the dose from 500 to 2000
mA*hour.

Absorbance

0.08

Although the surface reduction layer
disappeared, refractive index changes were also
found for the samples irradiated by UR with thespectrometer, as shown in Fig.4. The refractive
index changes in Fig.4 are lower than the one
caused by the surface reduction, but are still highenough for an application to optical devices.

80eV
120eV
180eV

0.06
0.04
0.02
0.00

200

250

300

wavelength (nm)350

Fig6. Optical absorbance for samples
irradiated by UR with the spectrometer at 3
peak-energies from 80-180 eV.
Conclusions
UR-irradiatedsamples
showedclear
differences between by the radiation with andwithout the spectrometer. Those kinds ofmodification would be useful for silica-based
glass as optical material, but further
investigations are needed to determine the mosteffective radiation conditions
References[1] K.Moriwaki et al., LASTI Annual Report
vol.15 (2013).
[2] K.Moriwaki et al., LASTI Annual Report
vol.16 (2014).

Fig.4 Refractive index changes after
irradiation by UR with the spectrometer.

56

Effect of the soft X-rayon the surface of fluorinated DLC film
1

H. Takamatsu1, M. Okada1, M. Niibe1 , K. Kanda1
LASTI, University of Hyogo, 3-1-2 Koto, Kamigori, Ako, Hyogo 678-1205 Japan

Abstract
The effect of the soft X-ray on the surface of the fluorinated diamond-like carbon (F-DLC) film
was investigated. The studies of stylus profiler, X-ray photoelectron spectroscopy (XPS) and thenear-edge X-ray absorption fine structure (NEXAFS) showed that decrease in film thickness, fluorine desorption and increase in sp2/(sp2+sp3) ratio of C atom in the F-DLC film was caused by
the irradiation of the soft X-ray.

1. Introduction

carried out at BL06 of the NewSUBARU synchrotron facility. The SR at the BL06 irradiation chamber had a continuous spectrum from IR to soft Xray, lower than 1000 eV. This includes the ionizationenergy of a carbon K shell at 300 eV and the ionization energy of a fluorine K shell at 690 eV. As a result, the K shell electrons of the C and F atoms could
be excited by SR at BL06. During this experiment,
the electron energy of the NewSUBARU storage
ring was 1.0 GeV. The BL06 sample stage was room
temperature and the pressure in the chamber was theorder of 10-5 Pa. An SR dose [mA･h] was derived
from the product of the ring current [mA] and irradiation time [h].

The diamond-like carbon (DLC) film is wellknown for its various superior properties like highhardness, wear resistance, chemical inertness, andlow friction coefficients [1]. It’s used in various situation such as automobile parts, electronic components, medical instrument, the space industry, etc.,
and the development efforts for further performanceenhancements are conducted by many researchers
every day now.
The several properties of the DLC film were improved by doping of hetero elements such as Si, Ti
and W. Especially, the fluorinated diamond-like carbon (F-DLC), which contains fluorine atom in the
DLC film has some excellent properties, such as low
surface energy, low-dielectric constant, chemical inertness, etc., while keeping the high hardness of the
DLC film [2].
It has been reported that hydrogen was desorbed
from the hydrogenated DLC (H-DLC) film due tothe soft X-ray irradiation [3]. In this study, we investigated the effect of the soft X-ray on surface of the FDLC film. The steps between irradiation parts andunirradiation parts, the element composition ratio at
the film surface and the sp2/(sp2+sp3) ratio of C
atom in the film were measured with stylus profiler,
X-ray photoelectron spectroscopy (XPS) and the C-K
edge near edge X-ray absorption fine structure(NEXAFS) spectra, respectively.

Result and discussion
Fig.1 shows the film thickness change by the soft
X-ray irradiation. Red points indicate film thicknesses which were estimated using stylus profiler
from the step depth between irradiation part andunirradiation part on the F-DLC film surface. The
step was created by putting an Au mesh on the FDLC film surface, during irradiation of the soft Xray. The film thickness decreased precipitously
from 210 nm to 160 nm, in the SR dose range of 0300 mA･h, and became constant in about 150 nm
over 500 mA･h. Blue points show the film thickness which estimated from the section images of irradiated F-DLC without an Au mesh with the scanning electron microscope (SEM). The results of stylus profiler and SEM show the stop of the film
thickness decrease. In addition, the difference of thefilm thickness between the sample with Au meshand the sample without Au mesh did not appear.
Therefore it can be understood that stop of the film
thickness decrease is an end of the reaction not alimit of the aspect ratio.
Fig.2 shows change of the elementary composition
ratio in the soft X-ray irradiated F-DLC estimatedwith XPS. Red points, blue points and green points

2. Experiments
The 210-nm-thick F-DLC film was deposited on
Si wafers by using a plasma-enhanced CVD method.
The hydrogen content and the fluorine content of
the F-DLC film were estimated, respectively, to be≈2 at.％ and ≈40 at.％ with the combination of
Rutherford backscattering spectrometry (RBS) andelastic recoil detection analysis (ERDA) techniques.
The soft X-ray irradiation of the F-DLC film was57

Film thickness [nm]show fluorine content, oxgen content, and carbon
content, respectively. The fluorine content decreased precipitously from 0.8 to 0.2, in the SR dose
range of 0-300 mA･h, and became constant in about
0.1 over 500 mA･h. The carbon content relatively
increased with a decrease in fluorine. As these results, it is clear that fluorine is desorbed from the FDLC film surface by the soft X-ray irradiation. The
oxgen content increased from 0 to 0.15, the range of
0-300 mA･h, and became constant about 0.2 over
500 mA･h. It is understood that the nonpair electronof carbon which created by fluorine desorption isstabilized by combination with oxgen in residual atmosphere.
Fig.3 shows the sp2/(sp2+sp3) ratio change of carbon in F-DLC by the soft X-ray irradiation. The
sp2/(sp2+sp3) ratio was estimated from the C-K
NEXAFS spectrum by comparison with the highlyordered pyrolytic graphite (HOPG) as a standard
sample. The sp2/(sp2+sp3) ratio increased precipitously from 0.4 to 0.6, in the range of 0-300 mA･h,and became constant in about 0.6 over 500 mA･h.
In other words, the bonding state of carbon varied
from diamond-like to graphite-like by irradiation of
SR dose with 300 mA･h. It is understood that thedangling bond of carbon which created by fluorine
desorption and dissociation of carbon single bonding formed carbon double bonding by recombination.

Au mesh
SEM

200

150

100

0

1000

2000

SR dose [mA・h]

Fig.1 The soft X-ray irradiation dose dependence of the film thickness with Stylus profiler and SEM

Elemental ratio

1

F

0.8

O

C

0.6
0.4
0.2
0

0

1000

SR Dose [mA・h]

2000

Fig.2 The soft X-ray irradiation dose dependence of the element composition ratio with XPS

Conclusion
The effect of the soft X-ray on surface of F-DLC film
was investigated by the measurements of the film
thickness with stylus profiler, the element composition ratio at the film surface with XPS and thesp2/(sp2+sp3) ratio of C atom with C-K edge
NEXAFS. In the range of 0-300 mA･h, the film
thiclness decreased precipitously from 210 nm to
160 nm, the fluorine content decreased precipitously from 0.8 to 0.2, and the sp2/(sp2+sp3) ratio
increased precipitously from 0.4 to 0.6. In the dose
region more than 500 mA･h, the effect of the soft Xray on surface of F-DLC film was not observed.

sp2/(sp2+sp3) ratio

1
0.8
0.6
0.4
0.2
0

0

1000

SR dose [mA・h]

2000

Fig.3 The soft X-ray irradiation dose dependence of the sp2/(sp2+sp3) ratio with
NEXAFS

References[1] A. Grill, Diamond Relat. Mater., 8 (1999) 428.
[2] S. Miyake et al., J. Tribol., 1991
[3] R. Imai et al., Diamond. Relat. Matel.
44(2014)8-10.

58

Evaluation of damage in an organic thin filmwith cluster ion sputtering
S. Fujita1, Y. Nohara1, M. Ohno1, Y. Haruyama2
Nissan Chemical Industries, Ltd, Chiba, Japan2
LASTI, University of Hyogo, Hyogo, Japan

1

Abstract
We investigated the changes of surface morphology and chemical bonding state of cluster ion
sputtered PMMA thin film to evaluate sputtering damage in an organic thin film. By measuring theatomic force microscope (AFM) image of sputtered PMMA, it was confirmed that the surface
roughness of PMMA increased with increasing incident cluster ion energy. On the other hand, thenear-edge X-ray absorption fine structure (NEXAFS) spectra at the carbon K-edge region, suggested
that the amount of C=C and C=O bonds in sputtered PMMA was influenced by the ion species andincident energy of ion.
Introduction
Ion sputter depth profiling has been widelyused with X-ray photoelectron spectroscopy(XPS) or time-of-flight secondary ion mass
spectrometry(TOF-SIMS)
forthecharacterization of thin film structures. However,
the monomer ion sputtering causes significant
damage to the structure of organic materials.
Therefore, in case of sputtering polymeric thinfilms, those chemical bonding state orcomposition ratio are changed from original state.
In order to improve this problem, the cluster ion
sputtering method has been attracting attention inrecent years. The cluster ion is a collection of
atomic or molecule ions, it has been reported that
it is possible to sputter organic materials at lower
damage than monomer ions. In the previous
studies, it was reported that cluster ions do not
penetrate deeply into target materials because
incident energy of each constituent ion was very
low, therefore, the energy of their impact was
deposited within the few nanometers of thesurface [1]. However, the mechanism has notbeen completely clarified yet. Therefore, weinvestigated changes of surface morphology andchemical bonding state of cluster ion sputtered
PMMA thin film to evaluate sputtering damage
in an organic thin film.

used for the purpose of comparison with thosecluster ions. The sputtering rate of each ion
species for PMMA was evaluated by XPS. Table
1 shows the sputtering condition at each ion
species. After sputtering, the surface roughness
was measured by AFM (Bruker Dimension Icon)
and the chemical bonding state was measured by
XPS and NEXAFS. For XPS measurements, amonochromatic Al Kα (hν = 1486.6 eV) X-ray
source was used. The NEXAFS measurements
were performed at NewSUBARU synchrotron
radiation (SR) facility on beamline 7B. NEXAFS
spectra were simultaneously measured by theAuger electron yield (AEY), total electron yield(TEY) and fluorescence yield (FY) methods. To
reduce the SR irradiation damage of the samples
during measurements, the samples were cooled atabout 80 K and NEXAFS spectra were recordedat this temperature.
Results and discussion
Fig.1 shows AFM images of each PMMA
surface after sputtering. Scanned area was all 10
× 10 μm. The value of average surface roughness(Ra) obtained from the AFM was described at thebottom of each image. It was confirmed that theeach surface roughness of PMMA after
sputtering increased as compared with that before
sputtering. At the surface after the Ar monomer
sputtering, a lot of hole with diameter of about150-200 nm were observed. Meanwhile, at thesurface after each cluster ion sputtering, thegranular structure was observed. Moreover, it
was confirmed that the surface roughness after
Ar-GCIB sputtering increased with increasing

Experiments
PMMA (Sigma-Aldrich, Mw = 120,000) was
dissolved in toluene as a 4 wt% solution. PMMA
thin films were prepared by spin coating on an
ITO/glass substrate with a thickness of about 150
nm. PMMA were sputtered with an ion gun
attached to the XPS (PHI 5000 VersaProbe and
PHI Quantera) instrument. In sputtering, Ar gas
cluster ion beam (Ar-GCIB) with a mean size of
about 2500 atoms/cluster and C60 cluster beam
were used. Moreover, Ar monomer ion was also59

Table.1 The sputtering condition at each ion species

incident ion energy. This was considered to be
due to the energy of each constituent ion in ArGCIB increased. These results suggest that ion
species and incident energy have a significant
effect on PMMA surface morphology.
Fig.2 shows the C 1s and O 1s XPS spectra of
the PMMA after sputtering. Three peaks wereobserved at 288.6, 286.4, and 285 eV in C 1s
spectrum. These peaks were assigned as C=O, CO, and C=C from PMMA, respectively.
Furthermore, two peaks were observed at 533.5
and 532 eV in O 1s spectrum. These peaks wereassigned as O-C, O=C from PMMA, respectively[2]. After Ar monomer sputtering, the intensitiesof C-O and C=O peaks decreased while that of CC peak increased. Therefore, it was confirmedthat the chemical bonding state of PMMA surface

Fig.2 XPS spectra of PMMA after
sputtering
C=C peak is derived from sputtering damage, andthe C=O peak from PMMA [3,4]. Next, weestimated the ratio of each bond intensity fromthe NEXAFS spectra for comparison. As shownin Fig.4, the amount of C=C was largest at Ar
monomer, followed in order by C60, Ar-GCIB
and before sputtering. Here, the amount of C=C
after cluster ion sputtering was not significantly
changed compared with that before sputtering.
On the other hand, the amount of C=O bond wassmallest at Ar monomer sputtering. The amountof C=O bond by the AEY and TEY methods
indicated opposite trend against C=C.
Furthermore, FY spectra showed that the ArGCIB sputtering did not change in the chemicalbonding state in PMMA thin film.

Fig.1 AFM images of PMMA surface
after sputtering
after Ar monomer sputtering was significantly
changed compared with that before sputtering.
Meanwhile, there was no significant change inthe cluster ion sputtered surface.
Fig.3 shows the C K-edge NEXAFS spectraof the PMMA after sputtering. The NEXAFS
spectra were normalized by the edge-jumpintensity. Two peaks were observed at 285 and289 eV. These peaks were assigned as a transition
from a carbon 1s to π* orbital of C=C, and to π*
of C=O, respectively [3]. It is considered that the60

Fig.4 The ratio of each bond intensity

Fig.3 C K-edge NEXAFS spectra ofPMMA after sputtering
References[1] G. Gillen et al., Rapid. Commun. Mass
Spectrom. 12, 1303, (1998)[2] C. Ton-That et al., Polymer. 42, 1121, (2001)[3] O. Dhez et al., J. Electron Spectrosc. Relat.
Phenom. 128, 85, (2003)[4] B. Pignataro et al., Nucl. Instrum. Methods
Phys. Res. B. 131, 141, (1997)

61

Molecular orientation in photoreactive liquid crystalline
polymer films observed by NEXAFS
Y. Haruyama1, Y. Taniguchi2, M. Kondo2, N. Kawatsuki2, M. Okada1, and S. Matsui1
1 Laboratory of Advanced Science and Technology for Industry, University of Hyogo
2Graduate School of Engineering, University of Hyogo

Abstract
The molecular orientation of the pre-aligned photoreactive liquid crystalline polymer PMCB10M
films has been investigated using the near-edge X-ray absorption fine structure (NEXAFS) at the C
K-edge region. By combining the thickness dependence of PMCB10M films and three types ofsimultaneous detection methods of NEXAFS measurements, the molecular orientations of
PMCB10M films at the near-surface (<2 nm), at the inner-surface (~10 nm) and in the bulk (>10nm) were evaluated. In addition, it was found that the orientation of the liquid crystalline
molecules near the surface was parallel to the surface irrespective of the thickness of PMCB10M
films.
Introduction
The studies on the photoinduced molecularorientation of the polymeric films have attracted
significant attention for a potentially wide range
of applications such as birefringent opticaldevices, the photo alignment layer of liquid
crystal displays, and optical memories. The
polymethacrylatecomprisedof
4methoxycinnamolybihenyl (MCB) side groups
connected via decylene spacers (PMCB10M) is
one of photoreactive liquid crystalline polymers[1, 2]. It was reported that the molecularorientation of photoreactive liquid crystalline
polymer controlled by the linearly polarized UV
radiation and the subsequent annealing procedure[1, 2]. However, the molecular orientation ofphotoreactive liquid crystalline polymer near thesurface and the interface between the film and thesubstrate is not clear. To investigate the molecularorientation of PMCB10M films, NEXAFS
spectra at the C K-edge region were measured bythree types of simultaneous detection methods
with the different probing depth.
Experiments
PMCB10M was synthesized as described in aprevious paper [1]. PMCB10M films of 15-150
nm thickness were prepared by spin-coating atetrahydrofuran (THF) solution of the polymers
onto ITO coated glasses. The pre-aligned
PMCB10M films were prepared by irradiating thelinearly polarized UV light to the films and by
subsequently annealing at 120-240 °C for 10
minutes.
NEXAFS experiments were performed at abeamline 7B of the NewSUBARU synchrotron
radiation (SR) facility, the University of Hyogo.
NEXAFS spectra were simultaneously measured
by Auger electron yield (AEY), total electron
yield (TEY) and fluorescence yield (FY) methods.

The sample could be rotated around a vertical axis
to change the incidence angle of the SR to thesample surface. The direction of the linear
polarization in the SR was horizontal. To evaluate
the molecular orientation of PMCB10M films,
NEXAFS spectra were recorded in parallel andperpendicular configurations, where the directionof linearly polarized UV light irradiated to thefilms was parallel and perpendicular to that of thelinear polarization in the SR, respectively.
Experiments and Results
Figures 1(a) and 1(b) show the C K-edge
NEXAFS spectra of pre-aligned PMCB10M films,
measured by the AEY method, as a function ofincidence angle of the SR in parallel andperpendicular configurations, respectively. The
thickness of PMCB10M films was 150 nm. A
sharp peak at 284.8 eV, which was assigned totransitions from the C 1s orbital to the unoccupied* orbitals originating from aromatic ring sites,
was observed [2, 3]. With increasing the incidence
angle, the intensity of the peak at 284.8 eV
decreased
remarkably
intheparallelconfiguration while it was almost unchanged in
the perpendicular configuration. This indicatesthat the orientation of the liquid crystalline
molecules in PMCB10M at the near-surface isparallel to the polarization direction of the UV
light. On the other hand, the angular dependenceof the intensity at 284.8 eV in the TEY method
became smaller than that in the AEY method asshown in figure 1(c). In addition, the angulardependence of the intensity at 284.8 eV in the FY
method (not shown) had the similar angulardependence to that in the TEY. These results
indicate that the orientations of the liquid
crystalline molecules in pre-aligned PMCB10M
films at the inner-surface and in the bulk are

62different from that at the near-surface.
NEXAFS spectra of pre-aligned PMCB10M
films in the thickness of 15 and 55 nm were alsomeasured in parallel and perpendicularconfigurations. In the case, the angulardependence of the intensity at 284.8 eV in the

AEY method showed the similar behaviour to thatin the thickness of 150 nm. Therefore, it was
found that the orientation of liquid crystalline
molecules near the surface was parallel to thesurface irrespective of the thickness of
PMCB10M films.

(a)

(c)

(b)

(c)

(d)

(d)

Fig. 1 C K-edge NEXAFS spectra of pre-aligned PMCB10M films, measured by the AEY and the
TEY methods, as a function of incidence angle of the SR in parallel (a), (c) and perpendicular (b), (d)configurations, respectively..
References[1] N. Kawatsuki and J. Horii: Mol. Cryst. Liq.
Cryst. 498, 49-58, (2009).
[2] N. Kawatsuki, Y. Taniguchi, M. Kondo, Y.
Haruyama, and S. Matsui: Macromolecules 48,
2203, (2015).
[3] N. Kawatsuki, Y. Inada, M. Kondo, Y.
Haruyama, and S. Matsui: Macromolecules 47,
2080, (2014).

63

A large takeoff-angle dependence of C-K emission spectra
observed in highly oriented pyrolytic graphite
1

Noritaka Takehira,1 Masahito Niibe,1 Yuma Araki,1 and Takashi Tokushima,2,1
Laboratory of Advanced Science and Technology for Industry, University of Hyogo,
2
SPring-8 Center, RIKEN

Abstract
We observed a large takeoff-angle dependence of C-K emissions in highly oriented pyrolytic
graphite (HOPG). The dependence changes by mosaic spread in HOPG samples and X-ray
excitation energy. At the excitation energy of 310 eV, far from the absorption edge, we observeda large takeoff-angle dependence of π → 1s emission, which has never been reported. According
to the band calculation for HOPG, the large angle dependency could be attributed to the resonanttransition of 1s electrons to π* state at the 25 eV higher than the Fermi level.
Experiment
Table 1 shows four type of commecially-available
HOPG crystal samples and their mosaic spread(Union Carbide Co. and Optigraph Inc.). The SXES
experiments were perfomed at the beamline BL09A [12] at the NewSUBARU SR facility. The
samples are fixed in a copper holder to measure theC-K emission spectra. The angle between the
directions of the incident beam and the take-out of
the emission spectrum is fixed to 90 °. The takeoffangle dependence of the emission spectra wasmeasured by rotating the sample varing from 15 ° to
75 ° around a vertical axis.

Introduction
The soft x-ray spectroscopy using highly brilliant
synchrotron radiation is a capable tool for analyzing
the local structure around an atom. In particular,
high-resolution x-ray emission spectroscopy and xray absorption spectroscopy in the soft x-ray region
are well suited for analyzing the local and electronic
structures of light-element materials because these
spectroscopies can provide high-resolution
elemental orbital information. Additionally, thecombination of soft x-ray emission and absorption
spectroscopies can investigate bandgap structure,
because they directly reflect the valence andconduction bands, respectively.
A number of studies [1-10] of the electron
structure of gaphite has been studied in detail,especially with the absorption and emission spectraof the soft X-rays. The layered strucuture ofgraphite leads the separation of electron orbitals : σorbitals spread in the basal plane, while π orbitals
are perpendicular to the plane. This difference in thepolarization of π and σ electrons is claritied by thedependence of X-ray emission and absorption
spectra of graphite on the angle of incidence to thesample surface.
We measured the takeoff-angle dependence of
the C-K emission spectra of an HOPG with the
newly constructed soft X-ray emission spectrometer(SXES) at the NewSUBARU SR facility [11]. As aresult, we observed a large take-off-angle
dependence of C-K emissions that has not beenpreviously reported. Also the mosaic spread of
HOPG and excitation energy dependence ofemission spectra is distinguished clearly.

Table 1. Four type of commecially-available
HOPG crystal samples and their mosaic spread.
samplemosaicspreadOptigraph Inc.
AGraphZ 0.4±0.1 °0.4±0.1 ° Union Carbide Co.
ZYA
0.8±0.2 ° Union Carbide Co.
ZYB
3.5±1.5 ° Union Carbide Co.
ZYH
Results and Discussion
Figure 1 shows the takeoff-angle dependence of
the C-K emission spectra measured for the
AGraphZ-HOPG. The excitation energy of the soft
X-rays used in this measurement was 310 eV.
Because the incident X-ray intensity changes uponrotation of the sample, all the emission spectra werenormalized to unity for the emission peak intensityof the σ → 1s transition at around 276 eV. The peakaround the energy 282 eV is found to have a large64

A shown in Figure 3, the large takeoff-angle
dependence was observed at 284.5 eV and 291.8 eV,
where the large resonant absorptions were also
observed. When viewing only the C-K absorption
spectra, particularly strong resonant absorption does
not appear at 310 eV. However, in the band
structure of the fairly high-energy side of thegraphite calculated by R.F. Willis et al. [15], there
is a portion of the high density of states named “π2”at 310 eV (25 eV higher than the Fermi level). The
large takeoff-angle dependence of the π emission
observed at 310 eV is believed to be related to theresonant photon absorption by the C1s → π2transition.

angle dependence, and it is identified as lightemission due to π → 1s transitions.
In previous reports [1-10], the intensities of πemission were at most comparable or less to the σemission intensity. We are the first to report theobservation that the π emission intensity is muchhigher than the σ emission.

Figure 1.Takeoff-angle dependence of C-K
emisson spectra for AGraphZ-HOPG at theexcitation energy of 310 eV.
Figure 2 shows the takeoff-angle dependence of
the intensity of π emission for four type of HOPG
samples at the excitation energy of 310 eV, and thecurves denote the calculated value using model ofideal graphite structure [13,14]. Because of mosaic
spread of HOPG samples, takeoff-angle
dependence were found to varied significantly. It isfound that as the quality of the crystal structure of
the graphite become better, the takeoff-angle
dependence of π emission increases.
Figure 3 shows the excitation energy dependenceof the integrated intensity of π emission ratio (πθ /π75) and C-K absorption spectra measured for the
AGraphZ-HOPG. It is found from the figure that the
integrated intensity of π emission exhibits a large
value at 284.5 eV where the sharp π* absorption
occurs and 291.8 eV where a σ* absorption
indicates an increase. Moreover, the integrated
intensity of π emission ratio was also found toincrease with a gradual curve at the excitationenergy of around 310 eV, as reported in Figure 1.

Figure 2. Intensity of π emission ratio (πθ / π75),
for various samples and calculated curve at theexcitation energy of 310 eV.

Figure 3.Excitation energy dependence ofintegrated intensity of π emission ratio (πθ / π75)
for AGraphZ-HOPG.

65Acknowledgments
This work was performed under the auspices of
MEXT (Ministry of Education, Culture, Science andTechnology, Japan) under the contract subject "Project
for Creation of Research Platforms and Sharing ofAdvanced Research Infrastructure.”

References[1] - R. A. Rosenberg, P. J. Love et al., Phys. Rev.
B. 33, 4034 (1986).
[2] - Y. Ma, N. Wassdahl et al., Phys. Rev. Lett.
69, 2598 (1992).
[3] - Y. Ma, P. Skytt et al., Phys. Rev. Lett. 71,
3725 (1993).
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10457 (1994).
[5] - J. A. Carlisle, E.L. Shirley et al., Phys. Rev.
Lett. 74, 1234 (1995).
[6] – J. H. Guo and J. Nordgren, J. Elec. Spectra.
Rel. 110, 105 (2000).
[7] – E. L. Shirley., J. Elec. Spectra. Rel. 110, 305(2000).
[8] – A. V. Sokolov, E. Z. Kurmaev et al., J. Exp.
Theor. Phys. 77, 108 (2003).
[9] – V. V. Belavin, A. V. Okotrub et al., J. Exp.
Theor. Phys. 103, 604 (2006).
[10] - L. Zhang, N. Schwertfager et al., Phys. Rev.
B. 86, 245430 (2012).
[11] - M. Niibe and T. Tokushima, AIP Conf.
Proc. (SRI2015), in press.
[12] - M. Niibe et al., Synchrotron Radiation
Instrumentation, AIP Conf. Proc. 705, 576 (2004).
[13] – A.Mansour, S.E.Schnatterly et al., Phys.
Rev. B 31, 6521 (1985).
[14] – A.Mansour, S.E.Schnatterly et al., Phys.
Rev. B 36, 9234 (1987).
[15] - R.F. Willis, B. Fitton, and G. S. Painter,
Phys. Rev. B 9, 1926 (1974).

66

Irradiation Effect of Oxygen Plasma to TiO2 Thin Films
Yuma Araki1, Masahito Niibe1, Retsuo Kawakami2, Noritaka Takehira1, Yoshitaka Nakano3(Univ. Hyogo 1, Tokushima Univ. 2, Chubu Univ3)
Abstract
In our previous study, we found that the TiO2 thin film prepared by sputtering deposition had
oxygen deficiency. Therefore, we irradiated oxygen plasma to the TiO2 film to decrease oxygen
deficiency and improve photocatalytic activity. Photocatalytic activity of the TiO2 thin films wasevaluated by measuring the decomposition rate of organic dye (brilliant blue FCF) with UV
irradiation. Composition of the film and irradiation damage were analyzed with X-ray
photoelectron spectroscopy (XPS) and near edge X-ray absorption fine structure (NEXAFS)
methods, respectively. As a result, O/Ti ratio at the surface of TiO2 thin films increased whenoxygen plasma was irradiated. And there is a high correlation between photocatalytic activity andO/Ti ratio at the surface.

Introduction
TiO2 is known as photocatalytic material and used
for many products. Therefore, it has been required
to improve the photocatalytic performance. In
generally, TiO2 are used as powder. However,using it as thin film is superior in transparency anduniformity. In our previous study, we succeeded to
produce anatase type TiO2 thin films by sputtering
on a glass substrate(1), and it had photocatalytic
activity. However, we found that the sample hadless activite than original single-crystal because ofoxygen deficiency(2). Therefore, we irradiated TiO2
thin films with oxygen plasma for intending todecrease oxygen vacancy density and to improve
photocatalytic activity.
Experiment
TiO2 thin film was coated on a glass substrateusing the facing target type magnetron sputtering
equipment(1). Then oxygen plasma was irradiatedto the films by dielectric barrier discharge system.
The flow rate of oxygen gas was 15 ml/min and gas
pressure and irradiation time were changed from10 to 1000 hPa and 60 to 180 min, respectively. In
this study, substrate temperature was risen byplasma irradiation. Therefore, to clarity the effectof substrate temperature, we made another sample
in which oxygen plasma was irradiated to the films
for a short time while heating the substrate by aheater. Oxygen plasma was irradiated with fiveminutes at gas pressure 1,000 hPa and substratetemperature was changed from 30 to 200 ℃.
O/Ti concentration ratio at the surface of TiO2
thin films was evaluated by X-ray photoelectron

spectroscopy (XPS, Shimadzu ESCA-1000).
Etching damage was analyzed by near edge X-ray
absorption fine structure (NEXAFS) of the Ti-L
absorption edge at the New SUBARU BL-09A. To
evaluate photocatalytic activity, TiO2 sample wassoaked in brilliant blue solution and irradiatedultraviolet rays using a black light and measured
the dye decomposition rate.
Result
The treatment time dependence of dye
decomposition rate and the O/Ti ratio at the surfaceof TiO2 thin film were shown in Fig.1 (a) and Fig.1(b), respectively. The dye decomposition rate andthe O/Ti ratio at the surface of TiO2 thin films
shows good correlation. Photocatalytic activity andO/Ti ratio at the surface of TiO2 thin films
improved when oxygen plasma was irradiated until
60 minutes. However, the O/Ti ratio decreased
when the oxygen plasma was irradiated more than
60 minutes. We thought that it was caused by a risein substrate temperature by the oxygen plasma
irradiation.
The heater temperature dependency of dye
decomposition rate and O/Ti ratio at the surface ofTiO2 thin film were shown in Fig.2 (a) and Fig.2(b), respectively. The dye decomposition rate andthe O/Ti ratio at the surface of TiO2 thin films
shows good correlation. However, the temperatureof substrate increased more than 30 degrees,
photocatalytic activity and O/Ti ratio at the surfaceof TiO2 thin films decreased. Because diffusivity
coefficient increased by substrate temperature rose,
oxygen could be diffused.

67

NEXAFS spectra of the TiO2 thin films wereshown in Fig 3. Etching damage was not observedin less than 1,000 hPa and at high temperature.
Therefore, photocatalytic activity of the TiO2 thinfilms had little influence by etching damage. As aresult, we succeeded to control an oxygen
deficiency under a certain condition. To improve
the photocatalytic activity, we have to suppress therise in substrate temperature by controlling
irradiation of the plasma and need to try further
development.
【References】
1) K. Tominaga,K. Okada, Y. Miyamoto, S.
Ohkuma, K. Shiraishi, K. kusaka , and T
Hanabusa , e-J. Surf . Sci . nanotechnol . 7 ,
290 (2009)2) R. Kawakami et al subtitled to J.Vac.Sci.
Technol.A(2015)

Fig.2 dye decomposition rate (a) and O/Ti ratio
treated with increasing temperature at the surface(b) of TiO2 thin film

Fig.1 dye decomposition rate (a) and O/Ti
ratio (b) at the surface of TiO2 thin films

Fig.3 Ti-L NEXAFS spectra of TiO2 thin films
treated at 100 hPa and various treatment time68Modification of horizontally aligned multi-walled carbon
nanotube films by Ar ion beam irradiation and its
characterization by soft x-ray spectroscopy
S. Honda1,7, M. Niibe2, M. Terasawa2,7, R. Hirase3, H. Yoshioka3, H. Izumi3, K. Niwase4, E. Taguchi5, T. Harada2,
Y. Muramatsu1, K.-Y. Lee6 and M. Oura7
1
Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, Hyogo 671-2280, Japan
2
Laboratory of Advanced Science and Technology for Industry, University of Hyogo, 3-1-2 Kouto, Kamigori,
Ako, Hyogo 678-1205, Japan
3
Hyogo Prefectural Institute of Technology, Kobe 654-0037, Japan
4
Hyogo University of Teacher Education, Kato, Hyogo 673-1494, Japan
5
Osaka University, Ibaraki, Osaka 567-0047, Japan
6
Department of Electronic Engineering, National Taiwan University of Science and Technology, No. 43, Sec. 4,
Keelung Rd., Taipei 106, Taiwan
7
RIKEN SPring-8 Center, Sayo, Hyogo 679-5148, Japan

Abstract
Low energy Ar ions were irradiated to horizontally aligned multi-walled carbon nanotube (HAMWCNT) films using an electron cyclotron resonance ion source at SPring-8 BL17SU. Soft X-ray
photoelectron spectroscopy (XPS) and soft X-ray absorption spectroscopy (XAS) measurements
were performed to characterize electronic states of the irradiated HA-MWCNT films at BL17SU ofSPring-8 and BL10 of NewSUBARU.
Introduction
Nanostructured carbon materials such ascarbon nanotubes (CNTs) and graphenes havebeen extensively studied toward realization of
next-generation nanodevice applications. The
morphology of the CNTs strongly relates to thedevice performance. For example, horizontallyaligned multi-walled CNTs (HA-MWCNTs)
have been demonstrated to be applicable to thenanodevices such as sensors, and LSIinterconnects. On the other hand, irradiating
nanostructured carbon materials with energetic
charged particles, such as ions and electrons, isthought to be capable of tailoring their structure
and properties, and can be applied to process of
nanodevice fabrication. It was reported that theelectrical transport properties and structuralproperties of the individual CNT were modified
by the electron irradiation. Thus, many
researches were focused on the charged particle
irradiated individual CNT. However effects ofion irradiation on the structural properties and/or
electronic states of ensembles of HA-MWCNT
films have not been fully understood.

MWCNT films were characterized by scanningelectronmicroscopy(SEM),
Raman
spectroscopy
andtransmission
electronmicroscopy (TEM). In addition, soft X-ray
photoelectron spectroscopy (XPS) and soft X-ray
absorption spectroscopy (XAS) measurements
were performed at BL17SU at SPring-8 [2] andBL10 at NewSUBARU [3], respectively.
Results and Discussion
Figure 1 shows the C K-edge XAS spectra of
the HA-MWCNT films as-prepared andirradiated by Ar ions of different fluences. The
intensity was normalized using the * peakheight at 292 eV. The incident angle () of the SR
beam to the sample plane was varied from 45 to
90 (normal incidence). As shown in Fig. 1(a), it
is apparent that as-prepared HA-MWCNT films
shows an inverse dependence of the * peakheight at 285 eV with increasing . On the other
hand, for the irradiated HA-MWCNT films, there
is no  dependence of the * peak height withincreasing Ar ion fluence. These results indicate
the amorphization of the MWCNTs after Ar ion
irradiation.
Figure 2 shows the C 1s XPS spectra of the
HA-MWCNT films as-prepared and irradiated byExperimental
HA-MWCNT films were grown by catalytic
thermal chemical vapor deposition. Electron
cyclotron resonance ion source at SPring-8
BL17SU [1] was employed for irradiation of
singly charged Ar ions with a energy of 5.0 keV.
The structural properties of irradiated HA-

69

(a)

(b)

as-preparedAr +1.01015 ions/cm2

*

270 275 280 285 290 295 300 305 310
Energy (eV)HOPG

Intensity (a.u.) / deg.
45
54.5
75
90

270 275 280 285 290 295 300 305 310
Energy (eV)

(d)

(c)

3.01015 ions/cm2

Carbon blackEF

Intensity (a.u.)

Intensity (a.u.)*h = 700 eV

1.01016 ions/cm2

1.01016 ions/cm2

3.01015 ions/cm2

Intensity (a.u.)

Intensity (a.u.)

Ar 3p

270 275 280 285 290 295 300 305 310
Energy (eV)0

10 20 30 40 50 60
Binding Energy (eV)Fig. 3 C valence band XPS spectra of the irradiated
HA-MWCNT films

270 275 280 285 290 295 300 305 310
Energy (eV)

Ar ions of different fluencies, with HOPG andcarbon black (CB, N330) as references. It was
found that the shape of C 1s XPS spectra of HAMWCNT films was changed from asymmetry tonear symmetry after Ar ion irradiation. The
spectra of carbon black (amorphous carbon) aresimilar to those of the irradiated HA-MWCNT
films. Since carbon black is composed of sp2hybridized carbon crystallites, sp2-hybridized
carbon hexagonal ring network in the MWCNT
may be destroyed and nonbenzenoid rings andedge
carbon atoms may be formed after the irradiation[4].

Moreover, as shown in Fig.3, additional
peaks appeared in C valence band XPS spectra
after the irradiation. It is also worth noting that C
valence band XPS spectra in the vicinity of the
Fermi level of as-prepared and irradiated HAMWCNT films have different features. Theses
peaks in Fig. 3 can be assigned to O 2s electrons[5]. Compared with C 1s spectra, valence band
spectra were more sensitive to chemical
environment. The valence band spectra showedthat there were two different chemical states ofoxygen. The oxidation of C atoms may be
attributed to the defect on the MWCNT surface
induced by the irradiation. Furthermore, C Kedge and O K-edge XAS spectra of the irradiated
HA-MWCNT films were compared withstandard aromatic compounds having various
oxygenated functional groups (fingerprint
method [6]). As a result, carboxyl groups are
considered to be introduced onto the MWCNTs
after the irradiation.
References[1] M. Oura et al., J. Synchrotron Radiat. 5, 1058
(1998).
[2] K. Horiba et al., J. Electron Spectrosc. Relat.
Phenom. 144–147, 1027 (2005).
[3] Y. Muramatsu et al., Adv. X-Ray Chem.
Anal. , Japan 43, 407 (2012).
[4] R. D. Heidenreich et al., J. Appl. Cryst. 1, 1
(1968).
[5] Y. Xie et al., Surf. Sci. Spectra 1, 271 (1993).
[6] Y. Muramatsu et al., Surf. Rev. Lett. 9, 267(2002).

h = 700 eVCarbon black

HOPG

Intensity (a.u.)

1.01015 ions/cm2
as-prepared

Fig. 1 C K-edge XAS spectra of the irradiated
HA-MWCNT films.

Ar +Ar 3s O 2s

1.01016 ions/cm2

3.01015 ions/cm2
1.01015 ions/cm2

as-prepared282 283 284 285 286 287 288 289 290
Binding Energy (eV)Fig. 2 C 1s XPS spectra of the irradiated
HA-MWCNT films.

70

Development of High-Reflective W/Si-multilayer Diffraction
Grating for the Analysis of Fluorine Materials°Masaki Kuki1, Tomoyuki Uemura2, Masato Yamaguchi1, Tetsuo Harada1,
Takeo Watanabe1, Yasuji Muramatsu2, and Hiroo Kinoshita1
1Center for EUV Lithography, LASTI, University of Hyogo,
1-1-2 Kouto, Kamigori, Ako-gun, Hyogo, Japan
2
Graduate School of Engineering, University of Hyogo,
2167 Shosha, Himeji, Hyogo, Japankuki@lasti.u-hyogo.ac.jp

For the analysis of fluorine materials and 3d transition metals by soft-x-ray absorption spectroscopy, A
new diffraction grating with multilayer coating was installed at the BL-10 beamline of the NewSUBARU
synchrotron light source. The target photon energy range of this grating is from 500 eV to 1,000 eV, which
includes absorption edges of fluorine and 3d transition metals. The beam intensity of BL-10 in this range
was very low due to low reflectance of the diffraction grating for the usage of monochromator. In order toobtaining high reflectance, we developed wideband W/Si multilayer and this multilayer was coated on a
new diffraction grating. The reflectance of this multilayer was approximately 13-times higher than that ofprevious Ni single layer at the fluorine absorption energy edge of 697 eV. The beam intensity at theenergy of 697 eV using the new diffraction grating was over 40 times stronger than that using the previous
Ni-coated diffraction grating. As the result, using the new diffraction grating, it can be observed that thehigh-quality absorption spectrum of EUV resist at the absorption edge of fluorine and standard materialsof 3d transition metals. The results show that the W/Si multilayer coating significantly improved theperformance of the grating at the target energy range.
Keywords: W/Si multilayer, wideband multilayer grating, synchrotron light, soft x-ray absorption
spectroscopy

1. Introduction
Soft-x-ray absorption spectroscopy (XAS) is
widely used for the analysis of light element
materials, which measures absorption spectrum near
the absorption edges. The XAS system at BL10
beamline of NewSUBARU synchrotron light source[1-4]. For example, deterioration mechanism of tirerubber and engine oil were analyzed [2, 3]. In
addition, we analyzed the chemical reaction of theextreme ultraviolet (EUV) chemically amplified(CA) resist using BL-7 XAS system [5]. We
measured XAS spectrum around the fluorine
absorption energy edge of 697 eV to evaluate thedecomposition reaction of photoacid generator(PAG) of CA EUV resist during EUV exposure.
However, this previous result had large noise due tolow photon intensity in this energy region. In orderto develop of high-sensitive EUV resist, it isnecessary to measure the fluorine energy regionswith low noise in and sufficient energy resolution.
The main reason of the poor intensity own to the
low reflectance of the diffraction grating in BL-7
and BL-10 beamlines, which had a small deviation
angle of 168° for the diffraction grating.
Since in general, a CA resist is easy to deteriorate,
it is important to analyze the resist by XAS near the
resist process equipment for resist coating, baking,developing spin coater, developer, and hot platein the clean room. Thus a new diffraction grating
which had high reflectance on 697 eV for the usage
of XAS at BL-10 beamline of NewSUBARU
should be installed. For considering general usage of71

Fig.1．Schematic layout of BL-10 of NewSUBARU.

the horizontal direction. The monochromator typewhich was utilized for BL-10 beamline is the planevaried line-space grating (VLSG), and it was
described the paper written by Hettrick andUnderwood [7]. The reflected light by the sphericalconcave M0 mirror focused on the exit slit in thevertical direction by M1 concave mirror anddiffraction grating. Two gratings were installed in
the monochromator, which had groove densities of
600 mm-1 (G1) and 1,800 mm-1 (G2). The deviation
angle of the grating is small as 168°, because BL-10
was originally designed for low-energy use of theresearch for EUVL energy region. The G1 grating
was originally installed for the EUV research. The
G2 grating was installed for XAS measurement in2009. In this study, a new grating with groove
density of 2400 mm-1 (G3) was installed. The exit
slit is relayed up to 5.2 m downstream at unity
magnification by a vertical refocusing mirror, where
the focusing size is approximately 0.05 × 0.8 mm2
on a sample. The all GAOI of the three glancing
spherical mirrors such as M0, M1, and M2 is 3°.
The mirrors were coated with single layer ofplatinum with the thickness of 50 nm. The deviation
angle of the grating is 168°, and was corresponded
to GAOI of 6° with specular-reflection condition.
The G2 grating was coated with single layer of Ni
with the thickness of 100 nm. The calculated
reflectance of the glancing mirrors and G2 grating
are shown in Fig.2. These two data were calculated
value using the IMD software [8] in this paper. The

BL-10, target energy of the new grating was set
from 500 eV to 1,000 eV, which includes absorption
edges of fluorine and 3d transition materials. Highreflectance of the new grating is essential for the
precise reaction mechanism analysis of the resist forthe semiconductor devices.
The platinum coated grating would have notenough reflectance due to the small deviation angleof the grating for BL-10. For example in thesoft-x-ray emission spectroscopy, wideband
multilayer
coatingsignificantly
improvedreflectance of a grating [6]. Thus, we developed amultilayer coating and it was coated on the gratingin this study to enhance the reflectance in the target
energy region. The beam intensity and XAS
spectrum were evaluated with the newmultilayer-coated grating.
2. Experimental
2.1 Design of beamline BL-10
The optical layout of BL-10 of NewSUBARU isshown in Fig.1. This beamline was originallydesigned for reflectometry of EUV optics, where areflectometer is located at the end of the beamline.
The vacuum chamber for the reflectometer was used
for the XAS measurement. The entrance slit design
is slitless. The M0 mirror is a concave mirror with agrazing angle of incidence (GAOI) of 3°, whichhorizontally focuses on the sample which wassettled in the XAS chamber with magnification of
three. The acceptance angle of the M0 is 5 mrad in

72

W/Si multilayer is shown in Fig. 4. As a results, it
was achieved that high reflectance the diffraction
grating of over 10% in the whole target energy
region by coating an aperiodic-designed W/Si
multilayer.

surface roughness was assumed to be 1 nm. Since
the reflectance of the glancing mirrors wasapproximately 30% at the photon energy of 697 eV,
the reflectance of the grating requires higher than
10% in the target energy region. However, since thereflectance of the G2 grating was less than 1% in theenergy range higher 700 eV, the beam intensity
becomes very low at the sample surface for XAS
experiment. Thus, the high reflective coating isneeded to increase the light intensity. And, thegroove height of 4.2 nm for the G3 grating was
optimized to achieve high diffraction efficiency at
the photo energy of 697 eV.

Fig. 3. Calculated reflectance of single metal layers
and W/Si multilayers for the grating coating.

Fig.2. Calculated reflectance of BL-10 opticalcomponents of the mirrors and the grating (G2).

2.2. Design of multilayer coating
In this study, a W/Si-multilayer coating wasdeveloped for the G3 grating to enhance thereflectance in the target photo energy region. The
material pair of the multilayer was chosen to W/Si
because of high optical contrast and low absorption
to achieve high reflectance. Figure 3 shows thecalculated reflectance of aperiodic W/Si multilayer,
periodic W/Si multilayer, Pt single layer, and Ni
single layer, with GAOI of 6°. Platinum is generally
used for mirror coating of glancing mirrors for the
beamline of the synchrotron. Surface roughness ofthe single layer was assumed to be 1 nm with the
thickness of 50 nm. Roughness of the multilayerinterface was assumed to 0.5 nm. The periodic W/Si
multilayer film had 10 periods of 3.0-nm-thick W
layer and 7.0-nm-thick Si layer. Reflectance of thisperiodic W/Si multilayer was approximately 30% at
the photon energy of 697 eV, and has more than
20% in the target photo energy region. As a results,
an aperiodic design had wideband reflectance asshown in Fig. 3, and the structural design of theFig.4. Structural design of the wideband
W/Simultilayer.
The multilayer had aperiodic structure which
consisted of one periodic multilayer coated on ten
periodic multilayer. And the multilayer thickness
was optimized to obtain the high reflectance in thephoton energy target region. The periodic structurereflects well in energy region from 800 to 1,000 eV,
where the period thickness was optimized to reflect
this region. And, the top two layers widely reflects
low-energy beam below 800 eV, because reflectanceof tungsten single layer was enough high in this low
energy region. Thicknesses of the two top layers
were optimized to make positive interference of thereflections from the top surfaces (vacuum/W, W/Si,
Si/W and W/Si). Further, the thickness of thismultilayer was easy to control in deposition because
the thickness of the period structure was able tomeasure with high accuracy by x-ray reflectivity(XRR) measurement.

73

resolution of 600 can be achieved around the photoenergy of 700 eV. A photodiode (IRD SXUV-100)
was used as a detector to measure the beam intensity.
GAOI was 6°. A 1-μm-thick Cu filter was installed
to cut the high order light from the grating. The
reflectance in photon energy range from 500 to 930
eV, because absorption edge of the Cu filter wasaround 930 eV.
2.5. XAS measurement of EUV resistThesamplewaspolyhydroxyl
styrene-co-tert-butylacrylate (PHS-TBA) resist witha photoacid generator of tri-phenyl sulfonium
nonaflate (TPS-nonaflate), which measured inprevious paper [5]. The resist film thickness of 50
nm was spin-coated on a wafer. EUV light of 91.8
eV with the G1 grating was exposed on the sample
with seven exposure dose condition from 0 to 98
mJ/cm2. XAS spectrum was measured by total
electron yield (TEY) method. The seven exposed
position was measured around fluorine absorption
edge of 650 to 730 eV with the G3 grating. The
exit-slit width was 20 μm, where the energy
resolution was 1,300 around 700 eV.

Fig.5. Schematic view of the magnetron-sputtering
deposition system.
2.3 Deposition system
The W/Si multilayers were prepared by amagnetron-sputtering deposition system as shown in
Fig. 5. A 6-inch RF cathode was used for Si layer
deposition, and a 6-inch DC cathode was used for W
layer deposition. Twelve samples of 6-inch Si wafer
were usually settled by large holding plate with 830
mm in diameter. Each 6-inch-wafer sample wassettled at the distance of 300 mm from the rotation
center on the holding plate. For each deposition
layer, the deposition layer thickness was controlled
by the rotation speed of the holding plate. The
deposition system was pumped down to the vacuum
pressure higher than 1.5 × 10-4 Pa, and typically thedeposition was carried out at the Ar pressure of 1.7
Pa. When W/Si multilayer was deposited on a Si
wafer at the Ar pressure of 0.17 Pa, the film waspeeled off due to high film stress. The Ar gas
pressure was chosen to 1.7 Pa to reduce the film
stress. At this Ar pressure condition, the deposited
multilayer did not peel off.
For the development of the multilayer, a Si wafer
was used as a substrate. The grating substrate is 150
mm in length, 30 mm in width, and 25 mm inthickness. And the groves were patterned in theregion of 130 mm (L) × 22 mm (W). In deposition,
the grating substrate was set the groove region
parallel to the rotation direction of the holding plate.

3. Results and discussions
Figure 6 shows the measurement result of thereflectance. At the photon energy of 697 eV for the
fluorine 1s core level absorption edge, thereflectance of the Ni single layer, the Pt single layer
and the wideband W/Si multilayer were about 0.7%,
2.7% and 13.4%, respectively. The reflectance of the
W/Si multilayer is 13 times higher than that of Ni
single layer. And since the W/Si multilayer had highreflectance of more than 10% for the photon energy
region from 500 to 930 eV, this multilayer wascoated on the G3 grating substrate and it was
installed in BL-10 for the soft x-ray absorption
spectroscopy.
Figure 7 shows the beam intensity measured by
the photodiode with the G2 and the G3 grating
without filters. The exit-slit width was 10 μm. The
electron current measured by the photodiode with
the G3 diffraction grating at the photon energy of
697 eV was 69 nA and the photodiode current was
40 times larger than that with the G2 diffraction
grating. In addition, the photon energy region from500 to 1,000 eV, the photodiode current was

2.4. Measurement condition of reflectance
Reflectance of W/Si multilayer on a Si wafer wasmeasured at the reflectometer of BL-10. Reflectanceof a 76.5-nm-thick Ni and 52.9-nm-thick Pt single
layers were also measured. The G2 grating waschosen. When the width of the exit slit was set to be
50 μm, the monochromated photon energy

74the photo energy of 1,020 eV was clearly resolved.
The TEY-XAS method using BL-10 beamline has agood capability to measure the absorption spectra toevaluate chemical bonding in the photon energy
region from 500 to 1100 eV.

significantly improved and was more than 50 nA.
This result shows the largest photon number can beobtained using the G3 diffraction grating in thetarget photon energy region.

Fig.6. Reflectance of the wideband W/Si-multilayer,
the Ni single-layer, the Pt single-layer samples

Fig.8. TEY-XAS measurement result of the resist atfluorine absorption edge

(a)

(b)

(c)

(d)

Fig.7. Beam intensity with G2 and G3 gratings
Figure 8 shows the result of TEY-XAS
measurement of the EUV CA resist material. The
absorption structure of fluorine 1s core level wasmeasured with a high signal-to-noise ratio. We
successfully observed the peak height of theabsorption spectra decreased slightly with increasing
the EUV exposure dose. This is indicated that thefluorine 1s core level of the anion of photo acidgenerator in the EUV CA resist decomposed during
EUV exposure. Figure 9 shows the 1s core levelabsorption spectra measured by TEY-XAS method
for the fluorine of the anion of PAG in the EUV
resist and 3d-transition-metal compounds. All the
spectra were measured with a high signal-to-noise
ratio. The monochromator had enough energy
resolution to evaluate the chemical bonding for thecompounds. In addition to the target energy region,
the absorption spectrum of Zn 1s core level around(e)Fig.9. TEY-XAS measurement result of the standard
samples such as (a) B2O3 and TiO2, (b) CaF, (c) CoO,(d) CuO and Cu2O3, and (e) ZnO compounds.
4. Conclusions
We developed high reflective and wideband
multilayer coating for the photon energy from 500 to
1,100 eV. This coating had aperiodic structure of
W/Si with 11 periods. The reflectance of this coating75

was 13 times higher than the previous Ni single
layer coating, and was over 10% in the target photon
energy region. We deposited the wideband
multilayer on the grating substrate of G3, which was
employed as a monochromator of BL-10 beamline
for the TEY-XAS measurement method. The beam
intensity was significantly improved more than 40
times at the absorption edge energy of fluorine 1s
core level. And, high photon intensity can beachieved in the target photon energy region. We
measured the resist sample using TEY-XAS method.
The fluorine decomposition reaction of the resist
was clearly measured with good signal-to-noise ratio.
And, the absorption structures of standard 3dtransition metal compounds were also resolved
clearly. This result shows BL-10 beamline had highcapability of XAS measurement in the photon
energy region from 500 to 1100 eV with a sufficientenergy resolution and high beam intensity. In
addition, the reflectometer of BL-10 can measure
the reflectance of the metal coatings on an opticalelement in this photo energy region, and it can bestrongly contributed the development of soft x-ray
optics. The well-developed W/Si aperiodic
multilayer diffraction grating can provide significant
improvement of beamline performance for the highenergy photon region.

References
1. Y. Muramatsu, A. Tsueda, T. Harada, and H.
Kinoshita, Adv. X-Ray Chem. Anal. Jpn. 43, 407(2012) (in Japanese).
2. Y. Muramatsu, A. Tsueda, T. Uemura, T. Harada,and H. Kinoshita, Adv. X-Ray Chem. Anal. Jpn. 44(2013) 243 (in Japanese).
3. T. Uemura, Y. Muramatsu, K. Nanbu, T. Harada,and H. Kinoshita, Adv. X-Ray Chem. Anal. Jpn. 45(2014) 269 (in Japanese).
4. T. Uemura, Y. Muramatsu, K. Nanbu, D.
Fukuyama, M. Kuki, T. Harada, T. Watanabe, and H.
Kinoshita, Adv. X-Ray Chem. Anal. Jpn. 46 (2015)(in Japanese, in printing).
5. K. Emura, T. Watanabe, M. Yamaguchi, H.
Tanino, T. Fukui, D. Shiono, Y. Haruyama, Y.
Muramatsu, K. Ohmori, K. Sato, T. Harada, and H.
Kinoshita, J. Photopolym. Sci. Technol. 27 (2014)
631.
6. T. Imazono, M. Koike, N. Hasegawa, M. Koeda,
T. Nagano, H. Sasai, Y. Oue, Z. Yonezawa, S.
Kuramoto, M. Terauchi, H. Takahashi, N. Handa,
and T. Murano, J. Phys: Conference Series 425(2013) 152008.
7. M. C. Hettrick and J. H. Underwood, AIP Conf.
Proc. 147 (1986) 237.
8. D. L. Windt, Comput. Phys. 12 (1998) 360.

76

Development of the molecular orientation analysis by soft
X-ray absorption spectroscopy (soft XAS)
Eiji Takahashi1, Katsuya Imanishi1, Shogo Suehiro1, Yoshiyuki Suzuri2,
Yuki Ota3, Yasuji Muramatsu3
Sumika Chemical Analysis Service, Ltd.,
1-135, Kasugade-Naka 3-chome, Konohana-ku, Osaka 554-0022, Japan
2
Innovation Center for Organic Electronics, Yamagata University,
1-808-48 Arcadia, Yonezawa, Yamagata 992-0119 Japan
3
Graduate School of Engineering, University of Hyogo,
2167, Shosha, Himeji, Hyogo 671-2280 Japan
1

Abstract
Soft X-ray absorption spectroscopy (soft XAS) can detect light elements at high sensitivity. In thisstudy, about a material used for organic light-emitting diodes, was analyzed for its molecularorientation by using XAS. We were able to determine the orientation angle by confirming horizontal
orientation of the molecules from the measurement results using XAS. As a result, we havedeveloped the analysis method of organic thin films with depth information, which will contributeto the optimization of manufacturing process.
Introduction
Organic multilayered thin films are used fororganic light-emitting diodes and organic solar cells.
In the manufacturing process of these films, it isimportant to control accurately the thickness of eachlayer in nm because the mixing ratio between theconstituents and their states affect the performanceof these films. Controlling of their molecularorientation has recently gaining attention as it would
lead to the improvement of thin film properties [1, 2].
Spectroscopic ellipsometry is known as a handy andeffective method for determining the molecularorientation of single-layer thin films [1]. For thinfilms of several tens of nm in thickness,
multilayered structure or mixed layers, whose
analysis is more difficult due to detection sensitivity
and effects from multiple elements, new evaluation
methods are required.
Soft X-ray absorption spectroscopy (soft XAS)
can detect light elements at high sensitivity. A
spectrum generated by this method reflects theelectronic state of each element. Based on thisspectrum, mixture ratio can be calculated by using astandard spectrum for each compound andmolecular orientation can be determined bymeasuring incident angle dependence [3, 4]. The
information depth is expected to be shallow because
soft X-rays have lower penetrabilities.
In this study, B3PyMPM (4,6-bis(3,5-di-3-pyridylphenyl)-2-methylpyrimidine), a material used
for electron transport layer, was analyzed for its
molecular orientation by using XAS.

ExperimentFig. 1 shows the organic materials used and themolecular structure. The molecular orientation was
analyzed using a thin film prepared by vapor
deposition of B3PyMPM on a silicon wafer (Fig. 1a).
(a)

(b)

Fig. 1(a) The structure of thin films, and(b) Molecular structure of the
B3PyMPM
XAS measurements were conducted at BL10
in the New SUBARU. The specimen surfaces were
irradiated with microbeam X-ray to obtain spectraby measuring the photoelectric current in thespecimens with an ammeter (Total electron yield).
The measurements were performed across thenitrogen k-edge and carbon k-edge (N K and C K).
Each signal intensity was normalized by theintensity of peaks (σ*) generated by nitrogen (orcarbon) σ bonds.
Results and Discussion
Fig. 2 shows the XAS spectra of B3PyMPM thinfilm obtained for different incident angles (θ) of soft
X-ray to the substrate.
At the N K edge of the spectra, the ratio of signal
intensity to the peak intensity generated by π bonds
between nitrogen and carbon became higher as the77

incident angle of X-ray decreased (smaller θ). Thiswas because the polarization direction of X-ray
coincided with the direction of π orbital, indicatingthat the main skeleton, pyrimidine, as well as thefour pyridine rings at molecular ends composing
B3PyMPM were oriented horizontally to thesubstrate.

molecules.
Conclusions
Up until now, there has been only few methods
available for accurate assessment of organic thinfilm's molecule orientation. In this study, XAS
proved to be capable of analyzing materials used fororganic light-emitting diodes. Also, calculations of
information depth enabled the analysis of organic
thin films with depth information, which willcontribute to the optimization of manufacturing
process.
References[1] D. Yokoyama: J. Mater. Chem., 21, 19187(2011).
[2] D. Yokoyama, H. Sasabe, Y. Furukawa, C.
Adachi, J. Kido: Adv. Funct. Mater.,21, 1375 (2011).
[3] F. Zheng, B.-N. Park, S. Seo, P. G. Evans, F. J.
Himpsel: J. Chem. Phys., 126, 154702 (2007).
[4] Y. Muramatsu, E. M. Gullikson: 'Advances in XRay Chemical Analysis, Japan' (in Japanese), 42,267 (2011).

Fig. 2 XAS spectra of B3PyMPM thin film
fordifferent X-ray incident angles(N K
edge)
These molecular orientations are in agreementwith the results of spectroscopic ellipsometry [2].
Fig. 3 shows the signal intensity ratio of π* to σ*plotted against the soft X-ray incident angles. We
referred to a method explained in a previous study[3]
in calculating the angle (α) between the normal
vector to the substrate surface and the π* orbital thatis perpendicular to the molecular plane, assumingthat all aromatic rings of B3PyMPM were on thesame plane. In this calculation, molecularorientation to the substrate surface would be
horizontal if α < 54.7° (the magic angle),
perpendicular if α > 54.7°, and non-oriented if α =54.7°.

Fig. 3 Molecular orientation of B3PyMPM
thin film(N K edge)
The calculation results were α = 47° for N K
edge, confirming horizontal orientation of the78Local structure analysis of graphitic carbon materials by X-ray
absorption spectroscopy
Kentaro Murayama1, Taizo Haruyama1, Rie Kazihara1, Yasuji Muramatsu2
1
MIKUNI COLOR, Ltd., 2University of Hyogo

Abstract
To characterize graphitic carbon materials by soft X-ray absorption spectroscopy, XANES of manygraphitic carbon samples were measured in BL10 at the NewSUBARU. It has been found that therelationship between the π* peak width and height in C K-XANES provides information on local
structure of hexagonal carbon layers. Hence, we have proposed the relationship which is named as“π* peak map” for the significant index of local structure analysis of graphitic carbon materials.
Introduction
Graphitic carbons have attracted muchattention for energy and transparent electrodematerials because of their superior electricalconductivity and low cost. The electricalconductivity is dependent on the π electron statesof sp2-carbon atoms in hexagonal carbon layers.
It is therefore required to develop a measurement
technique for obtaining some information of
local structure. We have previously found that
X-ray absorption near-edge structure (XANES)in the C K region provides information of edge
carbon atoms and/or nonbenzenoid rings in the
hexagonal carbon layers [1]. In this study, we
have measured C K-XANES of many industrial
graphitic carbon materials and deeply discuss theπ* profiles.
Experiments
Samples were commercially available
graphite, carbon nanotube (CNT), and carbon
black (CB) of furnace carbon black, acetylene
black, and Ketchen black. Physical properties ofthem are listed in Table 1. XANES
measurements were carried out at BL10 in the
NewSUBARU SR facility. Powder samples of
the carbon materials were pressed and held on
indium substrates, and total electron yield (TEY)
was measured by monitoring the sample
photocurrent in the C K region. Incident angle of
SR beam to the sample plane was turned at themagic angle of 54.5º. A 1800 mm-1 grating and a
20 µm slit were used for the C K-XANES
measurements.

layers. To clearly display the broader portion in
π* peak of carbon samples, subtracted spectra
between each carbon sample and HOPG areplotted on XANES with bold lines. The broader
portion can be shown as two peaks at 284.5 eV
and 286.2 eV which are named as peak a and b,
respectively. From our previous spectral analyses
by using the first-principle calculation code,
CASTEP, such the peaks a and b can be
explained by edge carbon atoms in hexagonalcarbon layers [2].
To further discuss the π* peak profile, wehave plotted the relationship between the π*
peak height (π*/σ* peak height ratio) and width(peak a) in Figure 2, which is named as “π* peakmap” [3]. In the map, carbon samples takecharacteristic distribution dependent on the kindof samples. The samples of graphite (denoted by
GRA in the figure) distribute near HOPG, which
Table. 1 Details of the graphitic carbon samples.
2 -1

Sample name Surface area / m g
FB1
250
FB2
12
FB3
220
FB4
560
FB5
350
FB6
125
FB7
79
FB8
370
FB9
260
FB10
180
FB11
290
FB12
290
FB13
25
FB14
142
FB15
244
FB16
119
FB17
79
FB18
56
AB1
39
AB2
69
AB3
370
AB4
156
AB5
380
AB6
63
AB7
58
KB1
800
KB2
377
GRA1
258.4
GRA2
9.9
GRA3
7.9
GRA4
GRA5
GRA6
GRA7
CNT1
CNT2

Results and Discussion
Figure 1 shows the C K-XANES of the
carbon samples and the highly oriented pyrolytic
graphite (HOPG) as a reference. Compared to
HOPG, the π* peak profile of carbon samples isgenerally broader. Such the broader π* peak
profile should reflect the the π electron statevariation of carbon atoms in hexagonal carbon

79

Particle size / nm
15
122
16
13
11
20
24
13
16
18
14
14
225
18
16
22
28
38
48
35
12
26

40

3

DBP absorption / cm 100g
52
41
105
91
115
150
77
69
55
98
98
155
130
80
144
101
158
140
160
250
220
282
234
218
360
300

-1

References[1] Y. Muramatsu, R. Harada, M. Motoyama, andE. M. Gullikson, TANSO, 236, 2-8 (2009).
[2] Y. Muramatsu, T. Ooe , T. Okada, and E.
M. Gullikson, Proc. of the 9th International
Symposiumon
AtomicLevel
Characterizations for New Materials andDevices ’13, ALC'13, 516-518 (2013).
[3] Y. Muramatsu, K. Murayama, and T. Okada,
Proc. of the 10th International Symposium on
Atomic Level Characterizations for New
Materials and Devices ’15, ALC'15, 27p-P-38(2015).

C K - XANES DAY1σ*π*

C K - XANES
σ*
π*

HOPG

HOPG

FB1

FB5

AB5

FB15

FB2

FB6

AB6

FB16

FB3

FB7

AB7

FB17

FB8

KB2

TEY normalized at π* peak (arb. Units)(sample) – (HOPG)
a b

FB4

a b

DAY2

(sample) – (HOPG)(sample)
a b

a b

AB4

FB12

GRA3

FB13

CNT1

FB14

KB1
280

285

290

295 300 280 285

GRA4

GRA2

FB11

AB3

– (HOPG)

GRA1

FB10
AB2

C K - XANES DAY3
σ*
π*

FB18

FB9

AB1

GRA5
GRA6
GRA7

CNT2
290

295

280

285

Photon energy / eV

290

295 300 280

285

290

295

Fig. 1 C K – XANES spectra of HOPG and graphitic carbon samples.

1.2

Peak height ratio, π* / σ*is rational because graphite particles should holdlarge hexagonal carbon layers. Samples of CNT
also distribute near HOPG, because CNT
consists of hexagonal carbon structures.
Acetylene black (AB) and Ketchen black (KB)
distribute on left side of furnace carbon (FB).
Such the distribution seems to reflect theelectrical conductivity dependent on local
structures; electrical conductivities of AB andKB are higher than those of FB. From theseresults, it can be considered that samples which
distribute on left side in π* peak map hold larger
hexagonal carbon layers and higher crystalline
structures. On the contrary, the samples whichhave some structural defects like edge carbon
atoms and/or nonbenzenoid rings are distributed
on right side in the map. This consideration fromthe π* peak map can not be obtained by thephysical properties shown in Table 1.
It is therefore concluded that the proposed
π* peak map is useful for characterization ofgraphitic carbons from the view point of local
structures.

1.0
0.8
0.6
HOPG
FB
KB

0.4
0.2
0

0

0.2
0.4
Peak a height

AB
CNT
GRA

0.6

Fig. 2 Relationship between the π* / σ* peak heightratio and peak a height (π* peak map).

80

300

Soft X-Ray Absorption Spectroscopy of Oxygen in
Rubber - Brass adhesive layer
Takashi Kakubo 1, Naoya Amino 1, Keita Nanbu 2, Yasuji Muramatsu 2,

1 Yokohama rubber Co., Ltd., 2-1 Oiwake, Hiratsuka, Kanagawa 254-8601, Japan

2 Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, Hyogo 671-2201,

Japan

Abstract
The chemical state of oxygen in the rubber and brass adhesion layer was evaluated by using totalelectron-yield soft X-ray absorption spectroscopy (TEY-XAS). Fatty acids including in rubbercompounds are influence to the adhesion of rubber and brass. Oxygen including in fatty acid on
rubber surface was estimated. After adhering rubber compound and brass plate by curing, theadhesion layer was sliced. Each of the surfaces was measured by TEY-XAS at NewSUBARU and
Advanced Light Source (ALS). The quantitative analysis of oxygen can be obtained from the peakheight ratio Oσ*/Cσ* in the TEY-XAS.
Introduction
The adhesion of rubber and steel in tire isquite important for safety driving of automobile.
If the adhesion systems do not work, the tire will
be break soon. So some analysis for the adhesion
system was evaluated [1, 2]. Fatty acids including
the rubber compounds affect to decrease adhesive
force of rubber and metal. Fatty acids areincluding in natural rubber, compounding agent
or cobalt salt. To evaluate the chemical state ofsurface oxygen in the rubber and brass adhesion
layer, TEY-XAS was used. After adhering rubbercompound to brass plate by curing, the rubber
layer was sliced. Each of the surfaces wasmeasured by TEY-XAS at NewSUBARU and at
Advanced Light Source (ALS). The quantitative
analysis of oxygen can be obtained from the peakheight ratio Oσ*/Cσ* from the results of TEYXAS.

Soft x-ray absorption spectra of the samples
were measured with the total-electron-yield(TEY) in beamline BL-10 at the NewSUBARU
and in beamline BL-6.3.2 at the Advanced Light
Source (ALS). Same samples were used for bothmeasurements, and both XAS results werecompared.
Figure 2 shows the results of XAS in the CK
and OK region of adhesion sample. Stearic acidwas used for standard sample of fatty acid.
Acetone extracted brass plate was used forNormal brass sample.
NS
Stearic acid

Total electron yield (arb.units)

Back

NS

Stearic acid

*

Back

Back

InsideInsideRubbersurface

RubbersurfaceBrasssurfaceBrasssurface

NormalBrass

Normal
Brass

ALS

*

InsideRubber
Brass

ALS

* *

Experiments and Results
Rubber compound including natural rubber,carbon black, Zinc oxide, sulfur and rubber
agents was mixed and prepared. After putting theuncured rubber on the brass plate, the rubber was
cured at 170 °C for 10min. To make it easier topeel off, only 0.5phr sulfur was mixed to therubber compound. The adhesion layer was sliced
by cutting knife after curing as shown in Figure
1. Each of the surfaces was measured by XAS.
HeatingCuringSlice

OK-XANESCK-XANES280

290

300 520

530

540

550

560

Rubber surface

Photon energy/ eVBrass surface

Fig.2 Soft x-ray absorption spectra in the CK
and the OK region of Rubber and Brassadhesion sample.

Fig.1 Adhesive samples for XAS measurement.

81

[2] K. Ozawa et al., Applied Surface Science.,
264, pp.297-304 (2013).

For rubber samples, * bonding in the CK
region were observed at 285eV. Some impurities
on the brass were observed from the result of
Normal brass. The peak of * bonding of ZnO in
the OK was shown at 538 eV. The peak of *
bonding of carboxyl group in the OK was shownat 540 eV. ZnO was mixed in the rubber, so the
ZnO component was detected by XAS
measurement.
Figure 3 shows that the peak height ratio O*/ C*. The peak height ratio of Rubber surface
and Brass surface are higher than that of Back or
Inside. The ratio in the rubber increases as close to
the brass. Oxygen including in fatty acid on rubber
surface was estimated. In addition, the ratio of
Brass surface and Normal brass are higher. Brassis originally stabilized by ZnO because of ZnO isformed on the brass surface. Thereby ZnO is
detected strongly on brass surface by XAS
measurement. The amount of oxygen derived ZnO
on brass surface is common to be reduced byvulcanization of rubber.
Peak height ratio , O * / C*

0.6
0.5
0.4
0.3
0.2
0.1 NS ALS
0Back

InsideSurfaceBrasssurface

Brass

Fig.3 Peak height ratio Oσ*/Cσ* of eachparts in adhesion layer.
The peak height ratios measured at ALS werehigher than that measured at NewSUBARU. The
tendency of oxygen content in each layer is similar.
Conclusions
The quantitative analysis of oxygen derived
fatty acid or ZnO can be obtained from the peakheight ratio Oσ*/Cσ* in the TEY-XAS. Oxygen
content of the rubber close to the brass isincreased. This result is due to fatty acids in therubber. It is possible to know the tendency of theoxygen component in the rubber and brassadhesion layer.
References[1] T. Hotaka et al., Nippon Gomu Kyokaishi.,
77,7, pp.244-249 (2004).

82

Analyses of surface state of detonation nanodiamond
Masahiro Nishikawa1, Ming Liu1, Akira Yamakawa1, and Yasuji Muramatsu2
1
Daicel Corporation, 2 University of Hyogo
Abstract
Detonation nanodiamond (DND) is a carbon nanomaterial promising for various applications,and controlling its surface state is very important to express its functionality. For this purpose,
we have started X-ray absorption near edge structure (XANES) measurements at BL-10 in the
NewSUBARU SR facility.
Introduction
Detonation nanodiamond (DND) is nanosized synthetic diamond with 4 ~ 5 nm in average
diameter of primary particle (Fig.1) [1]. It is akind of “carbon nanomaterial” and greatly
expected for wide range of applications by taking
advantage of physical properties of diamond incombination with the characteristics ofnanoparticles. DND is produced from explosives
by detonation process followed by purificationand dispersion processes (Fig.2). Daicel
Corporation has installed a test facility for
detonation process in Harima Plant (Hyogo,
Japan).
Due to small particle size, DND has large
specific surface area more than 300 m2/g. 10 ~20% of all atoms making up particles are exposedon the surface, where oxygen functional groups
like carboxylate or hydroxyl group exist (Fig.3).
The state of functional groups is affected bydetonation and purification conditions, andaffects the dispersibility in various media invarious conditions.
Analyzing surface state of DND precisely andcontrol that properly is very important to obtainfavorable dispersibility in target medium, bywhich the expression of distinguishedfunctionality of DND is expected.
For this purpose, we have started analyses of
DND surface state with X-ray absorption nearedge structure (XANES) measurement [2, 3].

Fig.2 Manufacturing processes of detonation
nanodiamond.

Fig.3 Illustration of nanodiamond primary particle
and its surface.
Experiments
XANES measurements were carried out at
BL-10 [4] in the NewSUBARU SR facility. CKedge, OK-edge and NK-edge XANES wererecorded by the total electron yield (TEY)method.
DND sample was manufactured by Daicel
Corporation. Average primary particle diameterof the sample was determined 4.1 nm according
to Sherrer’s equation by HMFW of the 111 peakof powder X-ray diffraction analysis. BET
specific surface area was 341 m2/g. Oxygen
content of the sample was estimated ca. 13% byelemental analysis, and nitrogen content was
2.5%.

2 nm

Primary particle

Fig.1
Transmission electron microscope(TEM) image of nanodiamond (by the courtesyof Prof. T. Hayashi, Shinshu University).

83

Absorption intensity

Results and Discussion
CK-edge XANES spectrum of DND is shownin Fig.4 together with that of highly oriented
pyrolytic graphite (HOPG).
Absorption peak at 285.1 eV is presumably
the peak from * of sp2 carbon on the DND
surface. The photon energy is slightly lower thanthat of HOPG (285.5 eV). It is supposed that sp2
carbon of DND would be less ordered thangraphitic carbon like HOPG. Further
investigation for the exact structure is needed.
Assuming that the intensity of * peak is liner tothe sp2 carbon content and that of HOPG is 100%,
sp2 carbon content of the DND sample isestimated 8.5% from the relative intensity of *
peak for DND, with standardized at 293 eV(Table 1). The peak at 286.7 eV is supposed tocome from hydroxylated sp2 carbon. It has been
observed that intensities of those peaks vary,
sometimes with subtle shift of photon energy, by
manufacturing
processes
andtreatment
conditions (data not shown).
OK-edge and NK-edge XANES spectra areshown as Fig. 5. We are presuming that the peakintensity of OK-edge XANES and that at 286.7
eV of CK-edge XANES, and oxygen content by
elemental analysis correlate one another. On theother hand, peak shape and intensity of NK-edge
XANES is unchanged among various samples.
Nitrogen in DND is derived from nitro group of
explosives and nitrogen content in DND is almost
the same among samples unless nitrogencontaining group is introduced by additional
treatment.
We are working for various samples withdifferent sources, processes and treatments forfurther elucidation.

Nanodiamond
HOPG

Absorption intensity

280

285

290

295

300

305

C=C

C-OH

285

287

Photon energy / eV

0.15

310

315

0.1
0.05
0

Fig. 4281

283

Photon energy / eV289

CK-edge XANES spectrum of DND

Absorption intensity

0.13
0.08
0.03
-0.02

520

540

560

Absorption intensity

Photon energy / eV

0.06
0.05
0.04
0.03
0.02
0.01
0
-0.01

390

400

410

420

Photon energy / eV

430

Fig. 5 OK-edge XANES (upper) and NK-edge
XANES (lower) spectra of DND

Table 1 Peak intensities of DND (standardized
at 293 eV of CK-edge XANES)
CK-edge XANES* (C=C) Relative intensity to * (C-OH)
285.1 eV
HOPG *286.7 eV
0.067
0.085
0.103

References[1] V. N. Mochalin, O. Shenderova, D. Ho and Y.
Gogotsi, Nature Nanotechnology, 7, 11-23(2012).
[2] S. Osswald, G. Yushin, V. Mochalin, S. O.
Kucheyev, and Y. Gogotsi, J. Am. Chem. Soc.,
128, 11635-11642 (2006).
[3] E. M. Zagrebina, A. V. Generalov, A. Y.
Klyushin, K. A. Simonov, N. A. Vinogradov, M.
Dubois, L. Frezet, N. Mårtensson, A. B.
Preobrajenski, and A. S. Vinogradov, J. Phys.
Chem. C, 119, 835-844 (2015).
[4] T. Uemura, Y. Muramatsu, K. Nambu, D.
Fukuyama, M. Kuki, T. Harada, T. Watanabe, andH. Kinoshita, Adv. X-ray Chem. Anal., Japan, 46,
317-325 (2015).

OK-edge XANES* (C=O)
* (OH)
530.9 eV538.7 eV
0.057
0.111

84

Analysis of the carbon blackby soft X-ray absorption spectroscopy
Atsusyoshi Inoue1, Masaya Fujisue2, Takeshi Hattori1, Tsuyoshi Takakura1,
Tomohiko Inoue1, Kentarou Murayama3, Yasuji Muramatsu3
1Mitsubishi Chemical Corporation, 2Mitsubishi Rayon Co. LTD, 3University of Hyogo

Abstract
Soft X-ray absorption spectroscopy (XAS) is effective analysis method for characterizing
chemical bonding state of carbon materials. For example, in the case of nano-graphite, wehave obtained information of edge carbon atoms in hexagonal carbon layer by analyzing the
XAS spectra in the CK region. In this study, we have evaluated variety of furnace carbon
blacks (CB) by the XAS measurement. As a result, we have found the inverse correlation
between the intensity of the peak attributed to edge carbon in hexagonal carbon layer andthe nitrogen absorption specific surface area (N2SA), Di-butyl phthalate oil absorption (DBP),
respectively. Furthermore, we have confirmed the difference of the local structure during thegraphitization.
Introduction
As a raw material of tires and rubber products,
CB is wildly used. In order to satisfy thecustomer’s requirements, variety of CBs areproduced. For further understanding of chemicaland physical bonding between CB and rubber, it isimportant to investigate the fundamental
structure, especially, the chemical bonding state ofhexagonal carbon layer. XAS measurement is a
powerful tool to identify carbon double bond andsingle bond, in addition, the edge carbon atoms inhexagonal carbon layer. In this report, we havefocused on the chemical bonding state change ofhexagonal carbon layer in CBs from XAS
measurements by changing the physicalproperties (N2SA, DBP, and graphitization) ofCBs, and those results are issued.

Results
Fig.1 shows the relationship between the π＊/σ＊
ratio and normalized peak-a height (CB(●),
nano-graphite (ᇞ)). Dotted line is the primary
approximation line of nano-graphite.
Plot of grinded nano-graphite shifted towards thelower right as we extend the grinding time. Thisshows that the grinding time increases thenumber of defect in hexagonal carbon layer.
In case of CB, π ＊ /σ ＊ and normalized peak-aheight are in the range of 0.7-0.9 and 0.3-0.5,
respectively. These plots are distributed along thedotted line.
Focusing on Sample1 and Sample2, plot shifted
towards upper left compared to Sample0. Sincegraphitized temperature is higher in Sample2
than in Sample1, the number of defect inhexagonal carbon layer is expected to be lower inSample2. Therefore, XAS could confirm therearrangement of crystallite during thegraphitization.

Experiments
XAS measurements by total electron yield (TEY)
were performed using synchrotron radiation in
BL-10 at the NewSUBARU [1]. CBs provided from
Mitsubishi Chemical Corporation have beenmeasured. Those samples have N2SA in the rangeof 28-374(m2/g) and DBP in the range of 46-137(ml/100g). Graphitized CBs (Sample1 andSample2) are also included.
We have considered the chemical bonding state ofcarbon by using two parameters, π ＊/σ ＊and thenormalized peak-a height. π＊/σ＊ is peak intensity
ratios between the π* peak and the σ ＊ peak.
Normalized peak-a height was obtained bysubtracting the measured spectrum from thehighly oriented pyrolytic graphite (HOPG)
spectrum as a reference [2,3]. Peak-a, attributed
to the edge carbon atoms in hexagonal carbon
layer, appears approximately at 284 eV in thesubtracted spectrum. For a reference, nanographites obtained by mechanically grinding
HOPG under Ar atmosphere were measured.

Π*/σ* Peak height ratio

1.1

Sample21

Sample1
Sample0

0.9
0.8
0.7
0.6

●:carbon black△:nano-graphite
0

0.2

0.4

0.6

Peak-a height

0.8

Fig.1 Relationship between peak heightratio (π＊/σ＊) and peak-a height (CB (●) and
nano-graphite (ᇞ)).

85

Fig.2 shows the relationship between N2SA andnormalized peak-a height (2a), along with relation
between DBP and normalized peak-a height (2b).
Normalized peak-a height of CB linearly decrease
as N2SA increase. Similar relation is observed for
DBP. It is new to know that the number of defectin hexagonal carbon layer is affected by DBP,
although it may take a little more time to identify
the cause of observed results.
Interestingly however, Sample1 and Sample2
show totally different balance. This result
suggested that we can produce CB with different
chemical bonding state, independent of N2SA andDBP.
As described above, XAS measurement is usefulin comparing the chemical bonding state ofhexagonal carbon layer of CB. In our future work,
we would like to identify the effect of oxygen at theedge of hexagonal carbon layer by analyzing
oxidized CBs.

Peak-a height

0.6
0.5

(2a)

Sample 00.4
0.3

Sample1

0.2
0.1

Sample2
0

100

200

N2SA(m2/g)

300

400

Peak-a height

0.6

References[1] T. Uemura, Y. Muramatsu, K. Nambu, D.
Fukuyama, M. Kuki, T. Harada, T. Watanabe, andH. Kinoshita, Adv. X-ray Chem. Anal., Japan, 46,
317-325 (2015).
[2] Y. Muramatsu, T. Ooe, T. Okada, and E.M.
Gullikson, Proc. 9th International Symposium on
Atomic Level Characterization for New Material
and Devices, 516-518 (2013).
[3] Y. Muramatsu, K. Murayama, and T. Okada,
Proc. 10th International Symposium on Atomic
Level Characterization for New Material andDevices’ 15, 27p-P-38 (2015).

0.5

Sample 0

(2b)

0.4
0.3

Sample1

0.2
0.1

Sample2
40

70

100

130

DBP (ml/100g)

160

Fig.2 Upper panel (2a) shows the relationshipbetween peak-a height and N2SA (m2/g). Lower
panel (2b) shows the relationship between peaka height and DBP (ml/100g).

86Development of Transmission Grating for EUV Interference
Lithography of 1X nm HP
Tsubasa Fukui, Hirohito Tanino, Yuki Fukuda, Masaki Kuki, Takeo Watanabe, Hiroo Kinoshita, andTetsuo Harada
Laboratory of Advanced Science and Technology for Industry, University of Hyogo
3-1-2 Koto, Kamigori, Ako-gun, Hyogo, 687-1205, Japan
tfukui@lasti.u-hyogo.ac.jp
The advanced feature size patterning process of semiconductor conductor devices was being charged with
the important role with development of an information-technology oriented society. Extreme ultraviolet
lithography (EUVL) is expected as a leading candidate of the next generation lithography for semiconductor
electronic devices. The development of EUV resist which has high resolution, high sensitivity, low LWR,
and low out gassing is a second critical issue of the EUVL. Development of the two-beam interference
exposure tool using the EUV light has been upgraded for the critical dimension of 10-nm-order in EUV
resist patterining process. This tool was installed at the 10.8-nm-long undulator beamline BL09B of
NewSUBARU synchrotron radiation facility. Using this EUV interference lithographic method, 15 nm hp
resist pattern had been replicated on a silicon wafer. The transmission grating fabrication is the mostsignificant key technology in the EUV interference lithography. The advanced fabrication process is applied
for the transmission-grating fabrication for the EUV resist patterning beyond the feature size of 15 nm, suchas 12.5 and 10 nm.
Keywords: EUV lithography, interference lithography, transmission diffraction grating

1. Introduction
EUVL [1] will be used in the semiconductor electronic
device high volume manufacturing for the patterning in the
16 nm feature size around 2016. The top three issues of the
EUVL are the development of 1) source, 2) resist, and 3)
mask. The critical issues of EUV resist are thesimultaneous achievement of the high resolution,
sensitivity, low LER, and low out gassing [2]. Currently,
on Feb. 25, 2015, ASML press release announced thatusing ASML NXE-3300B exposure beta tool, the EUVlight-source power increased to 90 W at the intermediate
focus position, and TSMC semiconductor chip
manufacturer exposed 1022 wafers in 24 hours. 10-nmfeature-size-pattering technology is required in 2020 for
the high volume manufacturing listed in the international
technology roadmap for semiconductor (ITRS) [3].
The resolution specification of ASML NXE3300B
EUV exposure tool is 22 nm. Thus it cannot reach to theresolution of 10-nm order. To accelerate the EUV resist
development of 10-nm order, it is very significant todevelop the EUV interference lithographic exposure tool
for the resolution achievement of 10-nm order [4]. The
EUV interference lithography had been developed andreplicated 15 nm line and space (L/S) resist pattern byusing two window-type transmission-diffraction grating(TDG) on which has 30 nm L/S grating pattern. In addition,
28-nm-diameter-hole resist pattern had been replicated byfour window-type TDG which has 40 nm L/S grating
pattern [5, 6, 7]. The replicated 15 nm L/S and 28 nm hole
resist patterns on a silicon wafer are shown in Fig. 1(a) and(b), respectively.
(a)

(b)

Fig. 1 (a) 15-nm-L/S inorganic-resist pattern, and (b) 28nm-diameter hole organic-resist pattern using EUV-IL
The reduction of the vibration amplitude from a dry
pump is a significant factor for the resist patterning of asmall feature size in the EUV-IL exposure. The
displacement of the vibration amplitude between the TDG
and wafer should be reduced to approximately 1/3 of thetarget resolution of 10 nm in EUV-IL [8]. The vibration
amplitude displacement of the frequency range from 0 to
50 Hz has been suppressed less than 3 nm.

87

The TDG has two window. In general, the coherent light isdiffracted into the 0th, ±1st, ±2st, …. -orders lights from adiffraction grating. The interference fringe is generated byinterfering with the +1st order light from one window of
TDG and -1st order light from another window of TDG,
and the generated-fringe pitch has a half pitch of the TDG
grating pattern. As a result, resist pattern pitch of the 1/2
pattern pitch of the TDG can be replicated on a wafer whensettle at the interference position. For example, a TDG with20 nm L/S grating pattern can form a resist pattern of 10
nm L/S on a wafer at the interference position.
In the resolution region of 10 nm and below, since thereplicated pattern is easy to be affected by the flare of theimaging optics, the flare control of the optics is verysignificant. However, since in the case of EUV-IL, EUVIL need not to use optics, there is no flare to be affected to
the fine pattern replication. Thus EUV-IL is a powerfulexposure tool to evaluate resist resolution and LWR
performance for the development of EUV resist material.

However, with taking care of the vibration suppression,
since the TDG fabrication for 10-nm-order EUV resist
patterning is most significant, this paper focused on the
fabrication of the TDG for the EUV resist patterning of 10nm-order resolution achievement using EUV-IL.
2. Experiment
2. 1. Interference lithography
A schematic view of the interference lithography which
was installed is shown in Fig. 2. An experimental chamber
was installed at 10.8-m-long undulator beamline BL09C.
The 1.0 GeV electron linear accelerator of the large
synchrotron radiation facility of SPring-8 is used as an
injector for the New SUBARU electron beam storage ringwhich is a medium scale light source. The circumstance of
this ring is approximately 118.9 m and the schematic viewof this facility was shown in Fig. 3.

Fig. 4 Principle of interference exposure
2.2 Transmission-diffraction gratings
A TDG is the significant key element of EUV-IL for theadvanced fine resist patterning. A schematic view of afabrication process of a TDG is shown in Fig. 5 [10].
Diffraction efficiency strongly depends on the absorbermaterial and its thickness. TaN material was selected to
employ as an absorber grating of the TDG because of thehigh diffraction efficiency, the good sputtering and dryetching performance.
First, 25 nm TDG tried to fabricate. And then 20 nm
TDG process was evaluated. To achive the advanced finepatterning for these TDGs, the following three specified
process should be employed.
1) The SiO2 hard mask process should be employed forthe patterning of the TaN layer with aspect ration of
approximately 3.
2) The low stress sputtering of the TaN and SiO2 layers
was required.
3) The center stop process was employed to cut off theincident light for the interfrence patterning.

Fig.2 A schematic view of the interference lithography
which was installed

Fig. 3 The schematics view of NewSUBARU
synchrotron light facility
Configuration of the two beam interference exposure
tool using the coherent EUV light is shown in Fig. 4 [9].

88fabricate a TDG with 25 and 20 nm L/S. In addition, resist
with higher etching tolerance is needed.
gL3002T (Gluon Lab.) resist which is a revised versionof ZEP520A resist and HSQ resist (XR-1541-002, Toray
Dow Corning) were tried to use in the fabrication processof the TDG. The averaged molecular weight of gL3002T
resist is 10 times larger than that of ZEP520A resist andalso has higher resolution and process stability comparison
to the organic positive type resist.
HSQ resist is a negative type resist of on the basis of thesilicon containing resist and has a resolution of 6 nm.
However, the sensitivity of HSQ resist is approximately 10
times lower than that of ZEP520A resist.
As results, gL3002T and HSQ resists were employed
for the fabarication of the TDG with a featsure size of 25
and 20 nm L/S grating pattern.

The transmission fabrication flow is listed as followings.
1) The low stress 100-nm thick Si3N4 double coated 4inches Si substrate was performed as the TDG
substrate.
2) The TaN and SiO2 layers which employed as anabsorber grating and hard mask respectively weresputtered on the substrate.
3) Electron beam resist was coated.
4) The resist was patterned by 50-keV-electron-directwriting tool.
5) The EB resist pattern was transformed to the SiO2
hard mask layer by dry etching process.
6) The hard mask pattern was transformed to the TaN
absorber grating by dry etching process.
7) The back side Si3N4 layer was dry etched.
8) The back side Si was removed by the KOH wet
etching process at the temperature of 90 ºC to performthe Si3N4 membrane.
9) A 2 m thick EB resist was coated to perform thecenter stop layer to cut off the direct incident EUV
light.
10) The center stop resist on the window area was
exposed by EB, and development and rinse
processing were carried out.
11) The remained resist was removed by O2 ashingprocess.

3. Results and Discussions
3.1 gL3002T resist process
The resist was spin coated on a SiO2 layer to be thethickness of 50 nm. Prebake was carried out at thetemperature of 180 ºC in 180 s. O-xylene and 2-propanol
was employed as a developer and rinse solutions,
respectively. A SEM image of the cross sectional view of
the replicated gL3002T resist pattern is shown in Fig. 6.
Both scanning electron microscope (SEM) images of 25
and 20 nm L/S resist patterns were replicated on a SiO2
layer as shown in Fig. 6(a) and (b), respectively.
(a)

(b)

Fig. 6 SEM images of (a) 25 nm and (b) 20 nm L/S
gL3002T resist pattern on SiO2 layer
Fig. 5 Fabrication process flow of TDG

A fine rectangular cross sectional shape of 25 nm L/S
gL3002T resist pattern was formed. However, since it
couldn't be formed in the case of 20 nm L/S resist pattern,
gL3002T was employed in the fabrication of TDG with afeature size of 25 nm.
SiO2 25 nm L/S pattern was formed by dry etching using
the 25 nm L/S gL3002T resist pattern as a mask. The crosssectional SEM image of SiO2 25 nm L/S pattern is shown

2.3 Resist processing
In this fabrication process of TDG, the electron beamlithography playes an important role to form a grating
pattern with a small feature size. ZEP520A (Nihon Zeon)
resist had been employed as the EB pattering of the TDG.
However this resist resolution limit was 25 nm in the EB
direct writing. A higher resolution EB regist is required to89

in Fig. 7(a). For this CF4 etching process, RF and bias
power were 100 W and 25 W, respectively. And chamber
vacuum pressure was 1.3 Pa, and the CF4 gas flow rate was
60 sccm.
TaN 25 nm L/S pattern was formed by dry etching using
the 25 nm L/S SiO2 pattern as a mask. The cross sectional
SEM image of TaN 25 nm L/S pattern is shown in Fig. 7(b).
For this Cl2 etching process, RF and bias power were 100
W and 25 W, respectively. And chamber vacuum pressure
was 1.3 Pa, and Cl2 gas flow rate was 25 sccm.
(a)the initial HSQ resist thickness was 36 nm. The 2.38%
TMAH alkali aqueous solution and deionized water were
employed as a developer and rinse solution.
Development and rinse conditions were at thetemperature of 22 ºC in the period of 30 s, and at the room
temperature in the period of 30 s, respectively.
(a)

(b)

(b)

Fig. 8 20 nm L/S pattern (a) affected by charging up on Si
substrate and (b) to stop the effect of charging up Espaser
was employed
Fig. 7 Cross sectional SEM images of (a) SiO2 and (b)TaN 25 nm L/S patterns formed after dry etching

In the case of a TDG fabrication, resist pattern should be
replicate SiO2 layer for the hard mask process. Figure 9shows cross sectional SEM image of 20 nm L/S HSQ
pattern on a SiO2 layer.

After the Si substrate back side etching and formulationof the center stop processes, 25 nm L/S TDG was succeed
to fabricate. Using TDG, 12.5 nm L/S resist pattern will be
replicate in the EUV-IL exposure.
3.2 HSQ resist process
Replicated 20 nm L/S HSQ resist pattern on a bare Si
wafer using 50 keV EB direct writing tool is shown in Fig.
8(a). However, HSQ resist pattern with a waving shape
was replicated because of charging up in EB lithography.
Since the exposure sensitivity of HSQ resist has
approximately 10 times lower than that of ZEP520 resist,large amount of negative electric charges are accumulatedon the resist surface during EB exposure. It is easier tooccur this charging up phenomenon using low sensitivity
EB resist material. Thus Espacer (Showa Denko) was
employed as a top coating material to avoid charging up
phenomenon. Espacer is water soluble and has a large
conductivity. Fig. 8(b) shows the CD-SEM image of 20
nm L/S HSQ resist pattern applied Espacer top-coatingprocess before the EB exposure. As shown in this figure,the waving shape disappeared and 20 nm L/S HSQ pattern
was succeed to replicate. The top-coating condition was
2,500 rpm in 60 s using spin coater, after the HSQ resist
coating on the substrate. For HSQ resist process condition,
spin-coating condition was 2,500 rpm in 60 s and prebake
was carrired out at the tempreature of 80 ºC in 80 s. And

Fig. 9 20 nm L/S pattern with Espaser process
2.38% TMAH alkali aqueous solution was employed
for the development. The cross sectional resist patternshape is not a rectangular. To obtain the rectangular crosssectional shape of HSQ resist pattern, the alkaline strong
NaOH aqueous solution was employed. To raise osmosisof NaOH into the HSQ resist material, NaCl was added.
Finally, mixture aqueous solution of 1% NaOH and 4%
NaCl was employed as a developer. As a result, 20 nm L/S
HSQ resist pattern with a rectangle-cross-sectional shape
was replicated with employing the mixture developer
solution of NaOH/NaCl. This cross sectional SEM imageis shown in Fig. 10(a). The thickness was 36 nm.
SiO2 20 nm L/S pattern was formed by dry etching using

90References
1. H. H. Solak, C. David, J. Gobrecht, V. Golovkina, F.
Cerrina, S.O. Kim, P.F. Nealey / Microelectronic
Engneering 67 (2003) 56.
2. The summaries of the International Symposium of
Extreme Ultraviolet Lithography 2010
3. ITRS Roadmap [http//www.itrs.net/].
4. Yasuyuki Fukushima, Naoki Sakagami, Teruhiko
Kimura, Kamaji Yoshito, Takafumi Iguchi, Yuya
Yamaguchi, Masaki Tada, Tetsuo Harada, Takeo
Watanabe, and Hiroo Kinoshita : “Development ofExtreme Ultraviolet Interference Lithography
System,” Jpn. J. Appl. Phys. 49 (2010) 06GD06-1 .
5. Y. Fukushima, Y. Yamaguchi, T. Kimura, T.
Iguchi, T. Harada, T. Watanabe and H. Kinoshita:“EUV Interference Lithography for 22 nm Node andBelow,” J. Photopolym. Sci. Technol. 23 (2011) 673.
6. T. Urayama, T. Watanabe, Y. Yamaguchi, N.
Matsuda, Y. Fukushima, T. Iguchi, T. Harada, H.
Kinoshita : “EUV Interference Lithography for 1X
nm,” J. Photopolym. Sci. Technol. 24 (2011) 153.
7. Y. Yamaguchi, Y. Fukushima, T. Harada, T.
Watanabe and H. Kinoshita: “Transmission grating
fabrication for replicating resist pattern of 20 nm andbelow,” Jpn. J. Appl. Phys. 50 (2011) 06GB10-1.
8. Hirohito Tanino, Tsubasa Fukui, Kazuya Emura, Yuta
Hayashi, Yuki Fukuda, Masaki Kuki, Masato Yamaguchi,
Tetsuo Harada, Takeo Watanabe, Hiroo Kinoshita:“Development of EUV interference lithography systemfor evaluation of EUV resist with hp 10 nm,” I. E. E. Jpn.
(2014) 7.
9. S. Suzuki, Y. Fukushima, R. Ohnishi, T. Watanabe, and H.
Kinoshita, “Pattern Replication in EUV Interference
Lithography,” J. Photopolym. Sci. Technol. 21 (2008) 435.
10. Y. Yamaguchi, Y. Fukushima, T. Iguchi, H. Kinoshita
T. Harada and T. Watanabe “Fabrication Process of EUVIL Transmission Grating,” J. Photopolym. Sci. Technol.
23(2010) 681.

the 20 nm L/S HSQ resist pattern as a mask. The crosssectional SEM image of SiO2 20 nm L/S pattern is shownin Fig. 10(b). Thickness was 20 nm. For this CF4 etchingprocess, RF power, Bias power, chamber pressure, CF4 gas
flow rate were 100 W, 25 W, 1.3 Pa, and 60 sccm, respectively.
(a)

(b)

Fig. 10 Cross sectional SEM images of 20 nm L/S (a)HSQ resist pattern, and (b) SiO2 pattern after CF4 dry
etching
As shown in this figure, the cross sectional shape of 20
nm SiO2 pattern is rectangle. TaN 20 nm L/S grating
pattern could be replicate employing this SiO2 pattern as amask in dry etching in Cl2 gas.
4. Conclusions
25 nm L/S gL3002T resist pattern with a rectangularcross sectional shape was formed. TaN grating pattern wasformed by CF4 and Cl2 gas dry etching. Fabrication of a
TDG which has 25 nm L/S grating pattern was completed
by forming the back side etching of Si substrate and thecenter stop process.
HSQ resist with 20 nm L/S rectangular cross sectional
pattern was formed by employing mixture aqueous
solution of 1 % NaOH and 4 % NaCl as a developer. 20
nm L/S of SiO2 was formed by CF4 gas dry etching. 20 nm
L/S of a TaN grating pattern can be transform by SiO2 20
nm L/S pattern as a Cl2 dry-etching mask. Using the TDG
with 20 nm L/S grating pattern, EUV resist will be
evaluated in EUV-IL exposure.

91

Trial fabrication of PTFE-filled E-plane waveguide coupler
using SR etching process
Mitsuyoshi Kishihara1, Akinobu Yamaguchi2, Yuichi Utsumi2, and Isao Ohta3
Faculty of Computer Science & System Engineering, Okayama Prefectural University
2
Laboratory of Advanced Science and Technology, University of Hyogo
3
University of Hyogo

1

Abstract
We report a trial fabrication of the PTFE-filled E-plane waveguide coupler for shortmillimeter-wave based on the SR etching process of PTFE, with the aim of developing integrated
waveguide circuits. In this report, an integrated PTFE pattern, in which the two 3-dB couplers arecascaded, is fabricated. Then, the frequency characteristics of the fabricated coupler are measured.
Introduction
The metal-covered waveguide circuits such as
H- and E-plane waveguide circuits suit with themillimeter-wave
andsubmillimeter-wave
applications requiring refined configurations,because the structures are very simple andvarious desired performances are realized by
optimization of the contour of circuit structure.
Recently,
variousmicromachining
technologies such as laser cutting, lithography,
etc. have been applied to the development ofcomponents in the field of microwave andmillimeter-wave engineering as well as in thefield of mechatronics, optics, and fluidics. Trialfabrications of a hollow waveguide hornantenna at W-band based on the fabrication
process using SU-8 photoresist, a coplanartransmission line and its filter at microwave
band based on the LIGA process, etc. have beenreported. Also, it has been reported that PTFE
(Polytetrafluoro-ethylene) microstructures canbe fabricated by direct exposure to synchrotron
radiation (SR) [1]. The SR direct etchingprocess has been applied to the fabrication ofvarious PTFE-filled waveguide circuits [2]. The
fabrication process is considered useful toconstruct the components for millimeter-wave
and submillimeter-wave frequencies.
In this report, a PTFE-filled E-plane
waveguide coupler for short millimeter-wave isfabricated based on the SR direct etchingprocess of PTFE, sputter deposition of metal,
and electroplating, with the aim of developing
integrated waveguide circuits [3]. First, acavity-type 3-dB directional coupler is designed
at 180 GHz. Then, an integrated PTFE pattern,in which the two 3-dB couplers are cascaded, isfabricated. For the measurement, a frequency
tripler is used to obtain the G-band (140-220GHz) signals from a V-band (50-75 GHz) source,and only the transmitted power is detected. The

frequency characteristics of the PTFE-filled
E-plane waveguide coupler are measured, andthe validity of the fabrication process is verified.
PTFE-Filled Waveguide Coupler
Figure 1 illustrates a structure of PTFE-filled
E-plane waveguide 3-dB coupler. It consists of arectangular cavity (a  b  d) and four E-plane
waveguides (w  d).The dimensions of thePTFE-filled waveguide were determined as 0.40mm  0.80 mm (w  d) for the 180 GHz
operation. The dimensions a, b of the cavity andthe position t were optimized to realize the 3-dB
coupler, and a = 1.77 mm, b = 1.42 mm, and t =0.27 mm were obtained.
In this report, an integrated PTFE pattern thatthe two 3-dB couplers are cascaded is fabricated,
and the transmitted characteristics of the circuit
are measured.
Fabrication
A trial fabrication of the PTFE-filled E-plane
waveguide coupler for 180 GHz operation was
performed based on the SR direct etchingprocess, sputter deposition of metal, andelectroplating. Figure 2 illustrates theexperimental situation of the SR etching process.
A stencil mask representing circuit pattern is puton the PTFE sheet (thickness: 0.80 mm). Then
X-ray is irradiated to obtain the PTFE pattern.
Figure 3 displays the integrated PTFE patternFig.1 Structure of PTFE-filled E-plane waveguide
coupler.

92

X-raymask
hotplate
PTFE sheet

Fig.2

PTFE sheet is etched by direct exposure to SR.

Fig.5
Frequency characteristics
Fig.3 Integrated PTFE pattern obtained by the SR direct cavity-type 3-dB couplers.
etching process. Two 3-dB couplers are cascaed.

Measurement
A measurement system is prepared using afrequency tripler (VDI WR5.13 Broadband
Tripler, 140 GHz - 220 GHz) and a detector(VDI WR5.1 Zero-Bias Detector, 140 GHz 220 GHz) to measure the frequency
characteristics of the 180 GHz PTFE-filledtheintegrated

waveguides. A vector network analyzer (Agilent
E8361C) is used for the V-band source (50 GHz- 70 GHz). The V-band signal is inputted to thetripler, and only the transmitted power isobserved as DC-voltage.
Figure 5 shows the frequency characteristicsof the integrated cavity-type 3-dB couplers
constructed of PTFE-filled E-plane waveguide.
Solid red line indicates the measured
transmission characteristics of the couplers. The
frequency characteristics of the S-parameters
using a high frequency structure simulator(HFSS) are plotted for comparison. It is foundthat the measured curve S21 shows similartendency to the simulated S21 except in theproximity of 176 GHz and 183 GHz. Although
the causes of the two falls of the transmission
characteristics must be made clear, thecombined output signal of the 3-dB couplers canbe observed in the G-band.

Fig.4 Integrated PTFE pattern covered with Au film by the
sputter deposition and electroplating.

of the two 3-dB couplers obtained by the SR
direct etching process. The amount of X-rays
exposed is 1700 Asec. It takes about 1.6 hours to
obtain the PTFE pattern. The fabrication
accuracy is within errors of ±7.5m, which
depends on the accuracy of the mask. Note thatthe stepped (4) transformers for impedance
matching are also embedded in the pattern in
Fig. 3.
After etching the PTFE pattern, thewaveguide structure covered with thin metal
film can be realized by sputtering Au all overthe surface of the PTFE pattern as shown in
Fig.4. The PTFE pattern is exposed to Ar plasma
for several minutes to perform surface
modification. Then, Au is deposited on theentire surface. In this report, the Au film of
about 500 nm in thickness is formed. To
increase the thickness of the Au film,
electroplating process is used. In this work, Au
film is increased up to 5 m. After forming theAu film, the integrated pattern of thePTFE-filled E-plane waveguide couplers is
obtained by removing the unnecessary frame.

ofConclusion
Trial fabrication of the cascaded PTFE-filled
E-plane waveguide 3-dB couplers for shortmillimeter-wave was demonstrated, and thetransmission characteristics were measured. The
fabrication process is considered applicable forthe development of integrated waveguidecircuits.
Acknowledgement
This work was supported by JSPS
KAKENHI Grant Number 26420314.
References[1] Y. Zhang, T. Katoh, M. Washio, H. Yamada,and S. Hamada, Applied Physics Letters, vol.67,
no.6, pp.872-874, Aug. 1995.
[2] M. Kishihara, H. Ikeuchi, Y. Utsumi, T.
Kawai, and I. Ohta, IEICE Trans. Electron.
vol.E95-C, no.1, pp. 122-129, Jan. 2012.
[3] M. Kishihara, H. Ikeuchi, Y. Utsumi, T.
Kawai, and I. Ohta, IEICE Trans. Electron.
vol.E95-C, no.1, pp. 122-129, Jan. 2012.

93Lab-on-a-CD to implement high precise unit chemical
operation for Immunoassay
Masaya Takeuchi1, Yasuto Arisue1, Yoshiaki Ukita2, Chiwa Kataoka3,
Toshiro Kobayashi4, Akinobu Yamaguchi1, Yuichi Utsumi1
1University of Hyogo, 2University of Yamanashi,
3 Carbuncle Bio ScienTech LLC, 4National Institute of Technology Tsuyama College

Abstract
The Lab-on-a-CD is a kind of micro analysis system that implement unit chemical operations such as
cleaning, mixing and so on. This device is circular and it manipulate solution by utilizing centrifugal
force when rotated. As an application of device, ELISA is effective. ELISA is immunoassay that enable
quantitative analysis by utilizing Antigen-antibody reaction. In this study, we fabricate Lab-on-a-CD
using capillary, siphon valve and attempt high accuracy of sequential sending solution assumed ELISA.

Introduction
In Clinical Examination, ELISA isfamous method that examine pestilencemaker such as protein and peptide and soon. ELISA enable quantitative analysis byutilizing antigen-antibody-reaction withenzyme. This is several types and explains
sandwiches method for example. First, we
uniformly fix primary-antibody to solid
phase surface (Fig.1(a)) and inject antigen(Fig.1(b)). Then part of antigen adhere
Primary-antibody. After washing extra
antigen (Fig.1(c)), we inject secondary
antibody fixing enzyme (Fig.1(d)) andlikewise wash it (Fig.1(e)). Finally,
substrate is injected (Fig.1(f)). Then
substrate reacts with enzyme and varies(a) Fixing Primary Antibody(b) Injecting Antigen(c) Washing Antigen(d) Injecting Secondary
Antibody(e) Washing Secondary
Antibody

its spectrum of absorbance. Thus,
quantitative analysis is possible tomeasuretheabsorbance.
Thereaction-stop-solution is actually injected
because of suppressing excess reaction ofsubstrate and Enzyme.
For way realized this ELISA, there ismethod that use micro titer plates. But
this method take long period of time andreduce reliability.
Also, the method
using robot is very expensive. This
prevents development to Clinic. For ameans solving these problem, micro
analysis system is attracted attention.
Micro analysis system is device that
integrate unit chemical operation such as
mixing, washing and so on by using fineflow-path. It is expected miniaturizationof device, reduction of reagent, shorteningof examination time and high precision.
There is Lab-on-a-CD in a kind of device
that utilize micro analysis system. This
device is disk-shaped and is formed
Flow-path from center to outside.
Centrifugal force is generated by rotatedthis and can send a liquid from center tooutside. We can realize unit chemical
operation by this.
In this study, we fabricate Lab-on-a-CD
for ELISA utilizing capillary valve, siphon
valve, mixing structure and attempt highefficiency and high accuracy.

(f) Injecting Matrix andEmission

Design of Lab-on-a-CD
Material of device uses PDMS. One of
two PDMS cut into a circle is dug
Flow-path by Rapid-typing-method[1].

Fig.1 Sandwiches method

94

The other is smooth. The Lab-on-a-CD
complete by pasting two PDMS. However,the PDMS is applied Hydrophilic treatment
beforehand.
Lab-on-a-CD using Capillary valve, Siphon
valve, mixing structure is operated while therotational speed up and down and realize
protocol that need to analyze in low rotation
speed.
Fig.2 shows concept figure of capillary
valve. Capillary valve is designed morethin than flow-path[2]. Liquid can stay bysurface tension between Capillary valve
andflow-path(Fig.2(b)).
Designof
Break-rotation-speed become possible byadjusting width of capillary valve because
strength of surface tension depends onthatofcapillaryvalve,
where
Break-rotation-speed is rotation speed
that solution of reserver flow out byCentrifugal
force.
Relationofbreak-rotation-speed 𝑓𝑓𝑐𝑐𝑐𝑐 and width ofcapillary valve is expressed by following
equation.
𝛾𝛾𝛾𝛾𝛾𝛾𝛾𝛾𝛾𝛾𝛾
𝜋𝜋 𝜌𝜌𝜌𝜌𝜌𝜌𝜌̅𝑑𝑑𝐻𝐻

𝛾𝛾𝛾𝛾𝛾𝛾𝛾𝛾𝛾𝛾𝛾

Design of break rotation speed become
possible.
Proposed Lab-on-a-CD need
operation
mixingSubstrate
andreaction-stop-solution. But quantity ofsolution dealt with micro analysis system
is micro scale and the nature of the fluid isdifference compared with macro scale.
There is two state of laminar flow andturbulence. Laminar flow is regular flow
Center of CD

R1
R2
θ

Where γ is surface tension of liquid, θ is contact
angle, ρ is density of liquid, dH is width ofvalve,∆𝑅𝑅 𝑅𝑅 𝑅𝑅2 − 𝑅𝑅1 , 𝑅𝑅̅ = (𝑅𝑅2 + 𝑅𝑅1 )/2.

Fig. 3.

R1

𝑅𝑅𝑒𝑒 =

𝜃𝜃

Flow-path(a) Capillary valve

Concept of siphon
valvethat the flow line of the fluid is parallel.
Turbulence is irregular flow that the flowline proceeds while crossing. Reynolds
number Re express the nature of the fluid.

Center of CD

Reserver𝐻𝐻(1)

𝑓𝑓𝑐𝑐𝑐𝑐 = √ 2

R2

(2)

𝑓𝑓𝑐𝑐𝑐𝑐 = √𝜋𝜋2𝜌𝜌𝜌𝜌𝜌𝜌𝜌̅𝑑𝑑

𝜌𝜌𝜌𝜌𝜌𝜌
𝜇𝜇(3)Where 𝜈𝜈 is flow velocity, d is innerdiameter of Flow-path, 𝜇𝜇 is viscosity.
Fluid that Reynolds number equals showshydrodynamically the equivalent nature.
Fluid becomes more irregular if thisnumber is large. It switches from Laminarflow to turbulence at about Re = 2000. In
micro analysis system, Reynolds number
becomes comparatively small numericalnumber and the nature of laminar flow
notably appear. In other words, the mix ofsolution is almost not occur in flow path incase of using Y-type-micro-mixer(Fig.4).
Thus, we must wait mix of solution a few(b) Contact angle

Fig. 2. Structure of Capillary valve

Siphon valve utilize capillarity and the principleof the siphon(Fig.3)[3]. Liquid of reserver enter
flow-path by capillarity and fulfill valve. Next,
by increasing rotation speed, strengthen
centrifugal force and send liquid by the principleof the siphon. Break rotation speed of Siphon
valve is expressed following equation.

95

Laminar flow

5
3

2

4

1
Fig. 4. Y-type-micro-mixer

7

6

8

9

1

Fig. 7. Concept of proposed Lab-on-a-CD

2
Mixing areaminutes in resever. We propose mixing
structure to solve this problem. Fig.5 shows theconcept of device used verification experiment.
Mixing area is formed between 1,2-reserver anddown reserver. When the solution runs
Flow-path, it yield vortex by using
mixing-structure, which is explained as below.
Velocity of fluid running pipe interior center isfaster than pipe interior surface because ofvalve, Siphon valve, mixing structure andperform “Sequential-selection-solution-sendingexperiment” assumed ELISA. Fig.7. showsconcept of fabricated device. The capillary
valve’s width of 1-6 reservers becomes thin as
the capillary number is large. 6, 7-reserver is thesame width. Thus, Break rotation speed increaseas the capillary number is large. Also 6,
7-reserver is the same Break rotation speed.
Fig.8 shows the relation between break rotation
speed calculated by actual width flow-path andmeasured by experiment. Measured value ofrespective break rotation speed is smaller thanthat calculated. As this reason, we consider thathydrophilic process of PDMS is not enough.
Next, we perform the experiments assuming
actual ELISA carried out by the sequential
unit chemical operation. Respective reserver isStrong stremeline
Weak stremeline

Value calculated by the actual valve widthExperimental value

Down reserver
Fig. 5.

Mixing structure

Rotation speed (rpm)

3000
2500
2000
1500
1000
500
0

Fig. 6. Formation of Coriolis force

1

2

3
4
5
Reserver number

6

7

Fig. 8. Relation of Break rotation speed
and Resever number

surface tension. Thus, Corioli’s force occurring
when rotating CD is different pipe interior
center and surface. The vortex occur by thisaction(Fig.6). Thus, liquid is easier to mix.

fulfilled with solution and rise rotation speed by1000 rpm per second. We verify whether
assumed experiment is possible or not.
1-reserver(antigen) valve is open as risingrotation speed and solution is injected
6-reserver(reaction field). This solution is sent

Experiments and Results
We fabricate Lab-on-a-CD utilizing Capillary96to 8-reserver(Waste-solution-reserver) using
siphon valve. These operation is likewise
performed 3-reserver(Primary-Antibody) and 2,
4-reserver (Washing-solution). Next, solution of
5-reserver(Substrate) is sent to 6-reserver.
Capillary valve of 6,7-reserver is broken byrotation speed further, the solution is sent to
9-reserver(inspection reserver) through themixing area. Fig.9 shows the experimental result.
Capillary valve, Siphon valve operate as
designed and the solution is mixed and can besent to inspection reserver. Thus we can realize
Sequential-selection-solution-sending assuming
ELISA.

Fig.9. Mixing structure[1] J. Cooper McDonald, et al., : “Fabrication of
Microfluidic system in poly”, Electrophoresis,
Vol.21, pp.27-40(2000)[2] Siyi Lai, Shengnian, et al., : “Design of a Compact
Dsik-like Microfluidic Platform for Enzyme-Linked
Immunosorbent Assay” , Anal. Chem, Vol.76, pp.
1832-1837 (2004)[3] Jens Ducree, et al., : “The centrifugal
microfluidic Bio- Disk platform”, Journal of
Micromechanics and Micro Engineering, Vol.17,
pp.103-115 (2007)

97

Proposal of Direct Digital Manufacturing Approach for
Production of Microfluidic Devices
Yoshiaki Ukita1, Akinobu Yamaguchi2, and Yuichi Utsumi2
1
University of Yamanashi
2
Laboratory of Advanced Science and Technology, University of Hyogo

Abstract
We propose and discuss direct digital manufacturing (or three-dimensional printing technology) forthe low-cost manufacturing of microfluidic devices. The difficulty of commercialization of
microfluidic product and advantage of direct digital manufacturing are briefly discussed. Then someexample of microfluidics manufacturing using direct digital manufacturing and flow pumping in thedeveloped microfluidic chips using centrifugal pumping are introduced.
Introduction
It has been widely shared problem that thedevelopment cost of microfluidic system forchemical and analytical system is too high torealize product with reasonable amount of initialinvestment, since beginning size of the market isniche or too small to compare to the investment
while it have to be grown in future. Direct digitalmanufacturing (or 3D printing technology) is
becoming popular style in industry for
production of final product. Especially in the caseof small volume production of complex resin
structure in niche market, it is advantageous since
it does not require the production of expensive
mold or molding facilities. In this report wewould like to propose and discuss the potential of
direct digital manufacturing for the production of
microfluidic devices.

Concept
Figure 1 depicts the difference of microfluidic
device production by conventional manner anddirect digital manufacturing. In the case of
conventional manner, the microfluidic system isdeveloped in research and development processusing small volume production method thattypically utilized in research such as
photolithography for the manufacturing of
microfluidic chips. Afterward when the prototypeof the product is developed the development
phase shifts to scaling up. In this shift of thephase it is forced to change the way of
manufacturing since typical research technology
is not suitable mass production of producttherefore there is great gap between research andscaling-up and there require great amount ofinvestment, time, and patience. On the other hand,in the case of direct digital manufacturing, theDeath valley
Feed backTime & cost

Chips
DriverFluidic controller
Detector integration

Mass production
Millions of $Reagent Device 10$/Kit
Driver 15,000$

Investigation forcommercialization

Limited applications
Limited users

Skipping Death valley

Reagent few$/Kit
Existing 3D printer few 100s $Mini‐centrifuge as driver few 100s $Diverse way of use and application

Chip manufacturing
by direct digitalmanufactureing

Fig. 1 Comparison of conventional way of commercialization and proposed way of commercialization by direct
digital manufacturing approach.

98

development of the research can be driven using
the 3D printer that potentially used by end-user
therefore once the product is developed in the
research phase the product can be directly
introduced to market since the product can besupplied with the style of electronic data.
Therefore direct digital manufacturing of
microchip is advantageous to greatly reduce thecost of initial investment for commercializationof microfluidic products [1].
Demonstration of direct digital manufacturingof microfluidic chips and centrifugal flow
control

Fig. 2 Demonstration of centrifugal microfluidic
pumping in monolithic microfluidic chip with 500 x
500 μm2 embedded microchannel.

Figure 2 shows the demonstration of centrifugal
microfluidic pumping in monolithic microfluidic
chip. Square shaped microchannels with 500 x
500 μm2 and 250 x 250 μm2 are successfully
embedded while some channels cannot flow
through the liquid due to clogging of the
microchannel due to residual resin in the
microchannel [2]. We also attempt autonomous

flow sequencing using water clock concept andsuccessfully demonstrated four step flow
injection at steadily rotating device that
manufactured by the use of existing three
dimensional printer [2, 3]. (data not shown) Referthe references for further detail of the research anddevelopment [1-3].
Summary
In this report we discussed the potential
advantage of the use of direct digitalmanufacturing concept for the production of
microfluidic
product.
Moreoverthedemonstration of microfluidic manufacturing andcentrifugal flow control are introduced. Owing
the concept of centrifugal microfluidic pumping
is also advantageous since it is possible to utilize
the mini-centrifuge, which already commerciallyavailable and cheap, as device driver.
References[1] Y. Ukita, Y. Utsumi, Y. Takamura, Direct
digital manufacturing of a mini-centrifuge-driven
centrifugal
microfluidic
deviceanddemonstrationofasmartphone-based
colorimetric enzyme-linked immunosorbent assay,
Analytical Methods, 8, 256-262, 2016 DOI:
10.1039/C5AY01969A[2] Y. Ukita, Y. Takamura, Y. Utsumi, Direct
DigitalManufacturingofAutonomous
Centrifugal Microfluidic Device, Japanese
Journal of Applied Physics, 55, 06GN02, 2016,
DOI: 10.7567/JJAP.55.06GN02[3] Y. Ukita, Y. Takamura, Y. Utsumi, Waterclock-based autonomous flow sequencing in
steadily rotating centrifugal microfluidic device,
Sensors and Actuators B, 220, 180-183., 201599

Synthesis of particles extracted from aqueous solution
induced by X-ray radiolysis using synchrotron radiation
Akinobu Yamaguchi1, Ikuo Okada2, Takao Fukuoka1, and Yuichi Utsumi1
1
Laboratory of Advanced Science and Technology, University of Hyogo
2
Synchrotron Radiation Research Center, Nagoya University

Abstract
We report the synthesis of metallic nano- and micro- particles from the corresponding liquid solution[gold(I) trisodium disulphite solution, electrical plating solution, including Na3Au(SO3)2 andNH2CH2CH2NH2 etc.] by X-ray radiolysis using synchrotron radiation. These results demonstrate
the behavior of three-dimensional printers, enabling us to build composite material structure withmetallic and other materials.
Introduction
The potential to fabricate metallic nano-andmicro materials on silicon substrates or othersubstrates from liquid solutions is ideal for threedimensional lithography systems, drug delivery
materials, Many methods are currently available
for the synthesis of such particles. For example,
synthesis of these particles has been successfully
demonstrated by sonochemical reaction,
chemical reduction of metallic ions in aqueous
solutions, and laser ablation and laser-induced
photochemical reactions, etc.
X- or -ray irradiation has also been
investigated as a radiation-assisted synthesis ofgold particles on a silicon substrate was reported
by Rosenberg and coworkers [1] and Yamaguchi
et al.[2] The method for synthesizing nano- andmicro-particles. Other groups also demonstrated
the synthesis of gold and nickel colloical particles
induced by synchrotron radiation (SR) X-ray
irradiation. The formation of such particles was
also performed using a laboratory X-ray source,
however the synthesis rate was very slow. The
physical and chemical mechanisms of particle
formation through X- or -ray radiolysis havebeen investigated by X-ray photoelectron
spectroscopy and optical spectroscopy. As aresult, the metallic particles are essentially
produced by a redox reaction induced by X- or ray irradiation within the solution. The X- or ray exposure enables us to easily induce chemical
reactions to obtain metallic particles, as theirradiation provides hydrogen and hydroxyl
radicals in the following matter:���, H ∗ , OH ∗ , H� O� , H� .
H� O �� ���
In this report, we demonstrate the synthesis of
metallic particles from corresponding aqueous
solutions by X-ray radiolysis. We reported theformation of gold, copper and iron particles. In
the case of gold particles, the prepared substrateenabled the measurement of molecule throughthe surface enhanced Raman spectroscopy.
Experiments and Results
Various metallic particles were directly
synthesized from appropriate solutions throughX-ray irradiation using the SR. [2] The
deposition experiment setup is schematicallyshown in Fig. 1. After SR X-ray exposure, thespecimen was washed with deionized water toremove residual materials. All experiments were

Fig. 1 Experimental setup for the X-ray irradiation of the
Na3Au(SO3)2 electroplating solution. Photon intensity
obtained from A: synchrotron radiation, B: mirror, C: Be
film, D: Al film, E: metallic solution and F: Stainlesssteel mask.

performed in air and at room temperature.
First, gold nanoparticles were prepared by Xray irradiation of electroplating solutions
consisted of a gold (I) trisodium disulphite 2 – 3 %Na3Au(SO3)2 and 1.4 – 1.9 % NH2CH2CH2NH2
etc. The solution was deposited on a 10 mm2
silicon substrate sealed by a SiN membraneprotected silicon and polytetrafluoroethylene(PTFE) plates. This assembly was covered bystainless steel frame holder. The PTFE plate
between SiN membrane and Si substrate protects
the solution seeping from the stainless steel frame100Fig. 3 Surface-enhanced Raman scattering (SERS)
spectra of 4bpy for different densities. The insets show
molecular formula of 4bpy and an SEM image of Au
nanoparticles.

Fig. 2 SEM images of Au nanoparticles acquired after
X-ray irradiation times of (a) 30 and (b) 60 s.
Corresponding high-resolution SEM images are shownin (a-i) and (b-i). (c) Substrate surface coverage by Au
nanoparticles as a function of X-ray irradiation time.

holder as shown in Fig. 1.
Figure 2 shows SEM images of Au
nanoparticles deposited on Si substrate in (a) 30
and (b) 60 s by X-ray irradiation. As shown in the
SEM images, quasi-spherical particles exhibiting
almost uniform nanometric sizes were created in
the irradiated area. In the electroplating solution,
the radial reaction is induced and Au ion is
reduced to the metallic Au as��
Au�SO� ���� � � � Au � �SO� .
The grains become denser and theirinterconnections
remainedrandomwithincreasing irradiation time. We found thatelementary particles ranging from a few to several
tens of nanometers gradually aggregated intolarger particles and clusters. The surface
roughness increase considerably up to a few

hundreds of nanometers with increasing
irradiation time. However, the film appeared
discontinuous. The surface coverage was plotted
as a function of the irradiation time as shown in
Fig. 2(c).
Next, the surface enhanced Raman scattering(SERS) of 4, 4’-bypiridine was measured using
the Si substrate on which gold nanoparticles andclusters was deposited. The SERS measurement
was performed using a simple Raman
spectrometer without any microscope (RAM100S, Lambda Vision Inc.) equipped with a 785
nm laser (100 mW) with 2�2 mm2 squared leaser
spot area. Figure 3 shows the density dependenceof SERS spectra of 4bpy using the substrateprepared by 600 s of X-ray irradiation.
Characteristic Raman peaks for 4bpy were visible
at 1000, 1200, 1280 and 1580 cm-1. Some SERSactive structures known as ‘hot-spot’ may exist on
the Si substrate.
In conclusion, Au nanoparticles weresynthesized by direct X-ray synchrotron radiationof an electroplating solution. Au cluster grew andaggregated to generate SERS-active structure‘hot-spots’ as the X-ray irradiation density
increased. This direct X-ray irradiation induced
metallic nanopartciles can also provide novel
lithography process to construct the additional
nanostructures onto the previously patterned area.
This convenient and high-sensitivity in situ SERS
platform can be used in Lab-on-a-Chip.
References[1] R. A. Rosenberg et al., J. Vac. Sci. Technol. B
16, 3535 (1998); Q. Ma et al., Appl. Phys. Lett.
76, 2014 (2000).
[2] A. Yamaguchi et al., Mater. Chem. Phys. 160,
205 (2015); A. Yamaguchi et al., Jpn. J. Appl.
Phys. 55, 055502 (2016).

101

Negative tone 50 nm line and space pattern fabrication
by electron beam lithography using NEB-22
Makoto Okada and Shinji Matsui
LASTI, Univ. of Hyogo

Abstract
Electron beam lithography (EBL) is an important technology as a nanofabrication process. To
delineate a high-resolution pattern with a short EB exposure time, EB resists are being developed.
NEB-22 is one of negative-tone chemically amplified EB resist. So far, it was difficult to fabricate
less than 100 nm line-and-space (L&S) pattern of NEB-22. We attempted a 50 nm scale L&S pattern
fabrication by EBL using a diluted NEB-22.
Introduction
Nanoimprint lithography (NIL) [1, 2] is a oneof the nanofabrication technologies, andnanoimprint mold with a high resolution pattern
is usually fabricated by electron beam lithography(EBL). The reversal pattern of the mold pattern isimprinted on the resin because NIL is a contact
process. Hence, it is important to choose thepositive- or negative-tone mold patterns
depending on the intended use.
NEB-22 (Sumitomo Chemical Co., NEB22A2) [3] is one of the negative-tone EB CARs
[4] and has potential in the fabrication of less than
50 nm line and space (L&S) pattern because a 36
nm isolated line was delineated by EBL [5]. If we
can fabricate 50 nm scale L&S pattern by EBL
using NEB-22 with a low dose, NEB-22 becomesa workable choice for fabricating negative-tone
less than 100 nm L&S pattern. We therefore
attempted EBL using NEB-22 for negative-tonehigh-resolution L&S patterning.
This study is published from Jpn. J. Appl. Phys.
54 (2015) 118004.
Experiments and Results
A direct-write EBL was carried out by Elionix
ELS-7500 system. The acceleration voltage andbeam current were 50 kV and 50 pA, respectively.
The exposed area was 300  1200 μm2. The
exposure dose was 40 μC/cm2. we diluted NEB22
with
1-methoxy-2-propyl
acetate(propyleneglycol monomethyl ether acetate,
PGMEA), which is the solvent of NEB-22, at aweight ratio of 2:1. The NEB-22 film spin-coatedat 4000 rpm was about 100-nm thickness, which
was measured by using JEOL JSM-6700F SEM
apparatus. A hexamethyldisilazane (HMDS)
treated Si substrate was used to increase adhesion
between the resist and the substrate. We carriedout post-apply bake (PAB) and post-exposurebake (PEB) for 2 min. PAB and PEB temperatures
were 90 and 95oC, respectively. A colddevelopment was carried out for fabricating thehigh-resolution NEB-22 pattern [6]. The exposed

NEB-22 substrate was soaked in 2.38%
tetramethylammonium hydroxide (TMAH) at 10o
C for 20 s. The rinse was done in deionized waterat room temperature for 30 s. We observed thefabricated NEB-22 pattern by SEM.
We first carried out EBL using undiluted NEB22 for delineating the high-resolution pattern.
Figures 1(a) and 1(b) show the SEM image of topview and cross-sectional SEM images of thefabricated pattern. We confirmed from the crosssectional SEM image that the pattern wasdeveloped, but it was collapsed because the patternheight was about 200 nm. This result shows that thelow height NEB-22 pattern fabrication is necessary
to achieve the high-resolution pattern by EBL.

(a)

(b)
Fig. 1 (a) Top-view and (b) cross-sectional
SEM images of the fabricated pattern by
EBL using undiluted NEB-22.
We next used the diluted NEB-22. Figures 2(a) and2(b) show the top-view and cross-sectional SEM

102

images of the NEB-22 pattern. The negative-tone
NEB-22 pattern was clearly fabricated. The lineand space-widths were 40 nm and 60 nm,
respectively. In addition, the pattern height was
about 90 nm. We then calculated the resist contrast
from the contrast curve in Fig. 3, as the slope of thelinear portion of the rising section of the curve andobtained 2.9. These results indicate that we
succeeded in the negative-tone fine pattern
fabrication by EBL using diluted NEB-22.
Fig. 3 Relationship between normalized
fine pattern height and exposure dose.
[7]. Copyright (2015) The Japan societyof Applied Physics.

(a)Conclusion
We challenged to fabricate the fine negativetone L&S pattern by EBL using diluted NEB-22.
The NEB-22 film thickness was about 100 nm
before EBL. The negative-tone pattern fabricationof 40-nm-line, 60-nm-space, and 90-nm-height
was succeeded. NEB-22 has a resolution
capability to fabricate 30 nm scale pattern. We
further continue the research to achieve the 30 nm
L&S patterning of NEB-22.
Acknowledgements
This work was partially supported by adaptable& seamless Technology Transfer Program
through Target-driven R&D (A-STEP) (Research
No. AS2615023M) funded by Japan Science andTechnology Agency.

(b)
Fig. 2 (a) Top-view and (b) cross-sectional
SEM images of the fabricated pattern by
EBL using diluted NEB-22 [7]. Copyright(2015) The Japan society of Applied
Physics.

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54, 118004 (2015).

103

105

106

List of publications(1) Papers
1.

"Photoneutron cross sections for neodymium isotopes: Toward a unified understanding of (γ ,n) and (n,γ )reactions in the rare earth region"
H.-T. Nyhus, T. Renstrøm, H. Utsunomiya, S. Goriely, D. M. Filipescu, I. Gheorghe, O. Tesileanu, T. Glodariu, T.
Shima, K. Takahisa, S. Miyamoto, Y.-W. Lui, S. Hilaire, S. Pe ́ru, M. Martini, L. Siess, and A. J. Koning
Physical Review C, 91, 015808-1-7 (2015).

2.

"ニュースバル放射光施設における放射光利用の新展開"
宮本修治
シリーズ「共用施設活用のススメ」第５回
OPTRONICS, Vol.34, No.5, pp.121-127 (2015). ISSN 0286-9659

3.

"レーザーコンプトン散乱 γ 線を用いた光核反応"
早川岳人, 宮本修治
展望, Isotope News, No.734, pp. 12-16 (2015).

4.

"Photoneutron Reactions in Nuclear Astrophysics"
H. Utsunomiya, S. Goriely, D.M. Filipescu, O. Tesileanu, I. Gheorghe,T. Glodariu, H.-T. Nyhus, T. RenstrØm,Y.-W. Lui, T. Shima, K. Takahisa, S. Miyamoto
Journal of Physics: Conference Series 590, 012023 (2015).

5.

"The γ-Ray Beam-Line at NewSUBARU"
H. Utsunomiya, S. Hashimoto, S. Miyamoto
Nuclear Physics News, vol.25, Issue 3, pp.25-29, July-September (2015). DOI:10.1080/10619127.2015.1067539

6.

"Photodisintegration of 9Be through the 1/2+ state and cluster dipole resonance"
H. Utsunomiya, S. Katayama, I. Gheorghe, S. Imai, H. Yamaguchi, D. Kahl, Y. Sakaguchi, T. Shima, K.
Takahisa, S. Miyamoto
Physical Review C, 92, pp. 064323-1-8 (2015).

7.

"Dispersion, spatial growth rate, and start current of a Cherenkov free-electron laser with negative-index
material"
Y. Wang, Y. Wei, D. Li, K. Takano, Ma. Nakajima, X. Jiang, X. Tang, X. Shi, Y. Gong, J. Feng, and S.
Miyamoto
Physics of Plasmas, 22, 083111-1-7 (2015).

8.

"HARPO, a gaseous TPC as a gamma telescope and polarimeter: first measurement in a polarised photon
beam between 1.7 and 74 MeV"
Delbart, S. Amano, D. Attié, D. Bernard, P. Bruelc, D. Calvet, P. Colas, S. Daté, M. Frotin, Y. Geerebaert, B.
Giebels, D. Götza, P. Gros, S. Hashimotob, D. Horan, T. Kotaka, M. Louzir, Y. Minamiyama, S. Miyamoto, H.
Ohkuma, P. Poilleux, I. Semeniouk, P. Sizun, A. Takemoto, S. Wang, M. Yamaguchi
The 34th International Cosmic Ray Conference, 30 July- 6 August, 2015
The Hague, The Netherlands, Proceedings of Science (POS)9.

"HARPO: beam characterization of a TPC for gamma-ray polarimetry and high angular-resolution
astronomy in the MeV-GeV range"
S. Wang, D. Bernard, P. Bruel, M. Frotin, Y. Geerebaert, B. Giebels, P. Gros, D. Horan, M. Louzir, P. Poilleux, I.
Semeniouk, D. Atti ́e, D. Calvet, P. Colas, A. Delbart, P. Sizun, D. Götz, S. Amano, T. Kotaka, S. Hashimoto, Y.
Minamiyama, A. Takemoto, M. Yamaguchi, S. Miyamoto, S. Dat é , H. Ohkuma
7th International Symposium on Large TPCs for Low-Energy Rare Event Detection
Journal of Physics: Conference Series 650, 012016 (2015). doi:10.1088/1742-6596/650/1/012016
1

107

10. "Damage Characteristics of n-GaN Crystal Etched with N2 Plasma by Soft X-ray Absorption
Spectroscopy"
Masahito Niibe, Takuya Kotaka, Retsuo Kawakami, Yoshitaka Nakano, Takashi Mukai
e-J. Surf. Sci. Nanotech, 14, 9-13 (2016).
11. "Surface Analysis of AlGaN Treated with CF4 and Ar Plasma Etching"
Shodai Hirai, Masahito Niibe, Retsuo Kawakami, Tatsuo Shirahama, Yoshitaka Nakano, Takashi Mukai
e-J. Surf. Sci. Nanotech, 13, 481-487 (2015).
12. "Resistance of Hydrogenated Titanium-doped Diamond-Like-Carbon Film to Hyperthermal Atomic
Oxygen"Kengo Kidena, Minami Endo, Hiroki Takamatsu, Masahito Niibe, Masahito Tagawa, Kumiko Yokota, Yuichi
Furuyama, Keiji Komatsu, Hidetoshi Saitoh and Kazuhiro Kanda
Metals. 5, 1957-1970 (2015).
13. "Hyperthermal Atomic Oxygen Beam Irradiation Effect on the Hydrogenated Si-doped DLC Film"
Kengo Kidena, Minami Endo, Hiroki Takamatsu, Ryo Imai, Masahito Niibe, Kumiko Yokota, Masahito Tagawa,Yuichi Furuyama, Keiji Komatsu, Hidetoshi Saitoh and Kazuhiro Kanda
Trans Mat. Res. Soc. Jpn. 40, 353-358 (2015).
14. "Structural dependence of corrosion resistance of amorphous carbon films against nitric acid"Atsuyuki Takarada, Tsuneo Suzuki, Kazuhiro Kanda, Masahito Niibe, Masayuki Nakano, Naoto Ohtake, Hiroki
Akasaka
Diamond and Related Materials, 51, 49-54 (2015)
15. "Study of Synchrotron Radiation Near-Edge X-Ray Absorption Fine-Structure of Amorphous
Hydrogenated Carbon Films at Various Thicknesses"
Sarayut Tunmee, Ratchadaporn Supruangnet, Hideki Nakajima, XiaoLong Zhou, Satoru Arakawa, Tsuneo
Suzuki, Kazuhiro Kanda, Haruhiko Ito, Kenji Komatsu, and Hidetoshi Saitoh
Journal of Nanomaterials, 2015, Article ID 276790 (2015).
16. "Surface functionalization of Diamond-like carbon film by the irradiation of soft X-ray"
Kazuhiro Kanda
CERAMICS JAPAN, 50, 46-52 (2015). (in Japanese)
17. "Comparison between AlGaN surfaces etched by carbon tetrafluoride and argon plasma: Effect of thefluorine impurities incorprated in the surface"
Retsuo Kawakami, Masahito Niibe, Yoshitaka Nakano, Tatsuo Shirahama, Shodai Hirai, Takashi Mukai
Vacuum, 119, 264-269 (2015).
18. "Ar+-irradiation-induced damage in hydride vapor-phase epitaxy GaN films"
Yoshitaka Nakano, Daisuke Ogawa, Keiji Nakamura, Retsuo Kawakami, and Masahito Niibe
J. Vac. Sci. Technol. A33, 043002 (2015).
19. "Recovery of x-ray absorption spectral profile in etched TiO2 thin films"
Keiji Sano, Masahito Niibe, Retsuo Kawakami and Yoshitaka Nakano
J. Vac. Sci. Technol. A33, 031403 (2015).
20. "Electrical Investigation of Deep-Level Defects Induced in AlGaN/GaN Heterostructures by CF4 Plasma
Treatments"
R. Kawakami, Y. Nakano, M. Niibe, T. Shirahama, and T. Mukai
ECS Solid State Letters, 4, 36-38 (2015).
2

108

21. "Three-dimensional hydrogen silsesquioxane nanostructure fabrication by reversal room-temperaturenanoimprint using poly(dimethylsiloxane) mold"N. Sugano, M. Okada, Y. Haruyama, and S. Matsui
Jpn. J. Appl. Phys. 54, 06FM05-1-06FM05-4 (2015).
22. "Evaluation of the fluorinated antisticking layer by using photoemission and NEXAFS spectroscopies"
Y. Haruyama, Y. Nakai, and S. Matsui
Applied Physics A 121, pp. 437–441 (2015).
23. "Electronic structure of fluorinated self-assembled monolayer investigated by photoelectron spectroscopy
in the valence band region"
Y. Haruyama and S. Matsui
Jpn. J. Appl. Phys. 54, 075202-1-075202-4 (2015).
24. "High-resolution line and space pattern fabrication by electron beam lithography using NEB-22 resist"
M. Okada and S. Matsui
Jpn. J. Appl. Phys. 54, 118004-1-118004-2 (2015).
25. "Influence of film thickness on the reorientation structure of photoalignable liquid crystalline polymer
films"
N. Kawatsuki, Y. Taniguchi, M. Kondo, Y. Haruyama, S. Matsui
Polymer 90, pp. 290-294 (2016).
26. "Phase Imaging Results of Phase Defect Using Micro Coherent EUV Scatterometry Microscope"
Tetsuo Harada, Hiraku Hashimoto, Tsuyoshi Amano, Hiroo Kinoshita, and Takeo Watanabe
J. Micro-Nanolith. Mem. 15, 021007 (2016).
27. "Actual defect observation results of an extreme ultraviolet blank mask by coherent diffraction imaging"
Tetsuo Harada, Hiraku Hashimoto, Tsuyoshi Amano, Hiroo Kinoshita, and Takeo WatanabeAppl. Phys. Express 9, 035202 (2016).
28. "Phase Imaging Results of Phase Defect Using Micro Coherent EUV Scatterometry Microscope"
Tetsuo Harada, Hiraku Hashimoto, Tsuyoshi Amano, Hiroo Kinoshita, and Takeo Watanabe
Proc. SPIE 9635 96351E (2015).
29. "Development of element technologies for EUVL"
Hiroo Kinoshita, Takeo Watanabe and Tetsuo HaradaAdv. Opt. Techn. 4, pp. 319-331 (2015).
30. "Development of High-Reflective W/Si-multilayer Diffraction Grating for the Analysis of Fluorine
Materials"
Masaki Kuki, Tomoyuki Uemura, Masato Yamaguchi, Tetsuo Harada, Takeo Watanabe, Yasuji Muramatsu, andHiroo Kinoshita
J. Photopolym. Sci. Technol., 28, pp. 531-536 (2015).
31. "Development of Transmission Grating for EUV Interference Lithography of 1X nm HP"
Tsubasa Fukui, Hirohito Tanino, Yuki Fukuda, Masaki Kuki, Takeo Watanabe, Hiroo Kinoshita, and Tetsuo
HaradaJ. Photopolym. Sci. Technol., 28, pp. 525-529 (2015).

3

10932. "Effective EUV Resist Outgassing Barrier Using a Novel Top Coat Material"
Xiaowei Wang, Georg Pawlowski, Tetsuo Okayasu, Masato Suzuki, Yusuke Hama, Takeo Watanabe, Tetsuo
Harada, and Hiroo Kinoshita
J. Photopolym. Sci. Technol., 28, pp. 111-117 (2015).
33. "Recent Progress in EUV Resist Outgas Research at EIDEC"
Eishi Shiobara, Isamu Takagi, Yukiko Kikuchi, Takeshi Sasami, Shinya Minegishi, Toru Fujimori, Takeo
Watanabe, Tetsuo Harada, Hiroo Kinoshita, and Soichi Inoue
J. Photopolym. Sci. Technol., 28, pp. 103-110 (2015).
34. "Development of a reflectometer for a large EUV mirror in NewSUBARU"Haruki Iguchi, Hiraku Hashimoto, Masaki Kuki, Tetsuo Harada, Takeo Watanabe, and Hiroo Kinoshita
Proc. SPIE 9658, 965819 (2015).
35. "EUV mask observations using a coherent EUV scatterometry microscope withhigh-harmonic-generation source"
Takahiro Fujino, Yusuke Tanaka, Tetsuo Harada, Yutaka Nagata, Takeo Watanabe, and Hiroo Kinoshita
Proc. SPIE 9658, 965818 (2015).

a36. "Quantitative phase imaging of a small phase structure on an extreme-ultraviolet mask by coherent
diffraction imaging"
Tetsuo Harada, Hiraku Hashimoto, Yusuke Tanaka, Tsuyoshi Amano, Takeo Watanabe, Hiroo Kinoshita
Appl. Phys. Express 8, 055202 (2015).
37. "Extreme ultraviolet mask observations using a coherent extreme ultraviolet scatterometry microscopewith a high-harmonic-generation source"
Takahiro Fujino, Yusuke Tanaka, Tetsuo Harada, Yutaka Nagata, Takeo Watanabe, and Hiroo Kinoshita
Jpn. J. Appl. Phys. 54, 06FC01 (2015).
38. "Analysis of EUV Resist Outgassing Depended on the Dosage"
E. Shiobara, I. Takagi, Y. Kikuchi, T. Sasami, S. Minegishi, T. Fujimori, T. Watanabe, T. Harada, H. Kinoshita, S.
Inoue
SPIE Proc. 9422, 942210 (2015).
39. "Study of Dill’s B parameter measurement of EUV resist"
Atsushi Sekiguchi, Yoko Matsumoto, Tetsuo Harada, Takeo Watanabe, and Hiroo Kinoshita
SPIE Proc. 9422, 94222L (2015).
40. "ニュースバル多目的ビームライン BL10 における軟 X 線吸収分析（4）；軟 X 線吸収分析装置の導入と有機薄膜試料の軟 X 線吸収・反射率分析"
植村智之，村松康司，南部啓太，福山大輝，九鬼真輝，原田哲男，渡邊健夫，木下博雄
Ｘ線分析の進歩第 46 集，pp. 317-325 (2015).
41. "Surface-enhanced Raman Scattering active metallic nanostructure fabricated by photochemical reactionof synchrotron radiation"
A. Yamaguchi, T. Matsumoto, I. Okada, I. Sakurai and Y. Utsumi
Materials Chemistry and Physics 160, 205-211 (2015).

4

11042. "On-chip integration of novel Au electrode with a higher order three-dimensional layer stacknanostructure for surface-enhanced Raman spectroscopy"
Akinobu Yamaguchi, Takao Fukuoka, Ryohei Hara, Kazuhisa Kuroda, Ryo Takahashi and Yuichi Utsumi
RSC Advances, 5, 73194 -73201 (2015).
43. "Fabrication of Dihedral Corner Reflector Array for Floating Image Manufactured by X-ray
Lithography using Synchrotron Radiation"
A. Yamaguchi, S. Maekawa, T. Yamane, I. Okada and Y. Utsumi
Transactions of the Japan Institute of Electronics Packaging 8(1), 23-28 (2015).
44. "Water-clock-based autonomous flow sequencing in steadily rotating centrifugal microfluidic device"
Yoshiaki Ukita, Yuzuru Takamura, Yuichi Utsumi
Sensors and Actuators B: Chemical, 220, 180-183 (2015).
45. "Proposal of Minicentrifuge-Compatible Centrifugal Microfluidic Device"
Yoshiaki Ukita, Yuichi Utsumi, Yuzuru Takamura
Sensors and Materials, 27, 5, 391-402 (2015).
46. "Fabrication of SERS Active Noble Metallic Nanostructure by Synchrotron Radiation Induced
Photochemical Reaction"
T. Matsumoto, I. Okada, I. Sakurai, Y. Utsumi and A. Yamaguchi
IEEE Xplore (Electronic Packaging and iMAPS All Asia Conference (ICEP-IACC), 2015 International
Conference on, Kyoto 2015), pp866-869 (2015).
47. "Fabrication and evaluation of dihedral corner reflector array for floating image manufactured bysynchrotron radiation"
T. Yamane, S. Maekawa, Y. Utsumi, I. Okada and A. Yamaguchi
IEEE Xplore (Electronic Packaging and iMAPS All Asia Conference (ICEP-IACC), 2015 International
Conference on, Kyoto 2015), pp436-439 (2015).
48. "Application of Gold Nanoparticles Self-assemblies to Unclonable Anti-counterfeiting Technology"
T. Fukuoka, A. Yamaguchi, R. Hara, T. Matsumoto, Y. Utsumi and Y. MoriIEEE Xplore (Electronic Packaging and iMAPS All Asia Conference (ICEP-IACC), 2015 International
Conference on, Kyoto 2015), pp432-435 (2015).
49. "X 線励起液相反応による金属ナノ粒子生成と応用 (Synthesis and application of gold nanoparticles
using photochemical reaction induced by X-ray irradiation)"
山口明啓，岡田育夫, 福岡隆夫，村上元規，内海裕一
MES 2015, pp265-268 (2015). (in Japanese)
50. "微量分子検出のための高次ナノ構造体の創製と実装 (Fabrication and Assembly of Higher Order
Nanostructure for Surface Enhanced Raman Scattering)"
山口明啓，福岡隆夫，内海裕一
Mate 2016, pp281-284 (2015). (in Japanese)
51. "放射光光化学反応による金属ナノ粒子生成 (Synthesis of metallic nanoparticles in liquid solution using
X-ray photochemical reaction)"
山口明啓，岡田育夫，櫻井郁也，福岡隆夫，石原マリ，内海裕一
Mate 2016, pp457-458 (2016). (in Japanese)

5111

(2) International meetings
1.

"Measurement of a Polarized Gamma Ray Beam from 1.7 to 74 MeV with the HARPO TPC"
P.Gros, D. Bernard, Ph. Bruel, M. Frotin, Y. Geerebaert, B. Giebels, Ph. Gros, D. Horan, M. Louzir, P.
Poilleux, I. Semeniouk, S. Wang, D. Calvet, D. Attié, P. Colas, A. Delbart, P. Sizun, Diego Götz, S.
Amano, T. Kotaka, S. Hashimoto, Y. Minamiyama, A. Takemoto, S. Miyamoto, M. Yamaguchi, S. Daté,
H. Ohkuma
13th Pisa Meeting on Advanced Detectors, 24-, May (2015).

2.

"NewSUBARU LCS Gamma-ray Source"
Shuji Miyamoto
International Workshop of Laser Compton Scattering Gamma Ray Sources and Their Applications,
NewSUBARU, Kouto, Japan, Nov. 11 - 12, 2015.

3.

Hold International Workshop 国際ワークショップ開催
International Workshop of Laser Compton Scattering Gamma Ray Sources and Their Applications,
NewSUBARU, Kouto, Japan, Nov. 11 - 12, 20154.

"Low-Temperature Crystallization of Si, Ge and Si-Nanocrystal by Soft X-Ray Irradiation"
N. Matsuo, A. Heya, S. Miyamoto, T. Mochizuki, K. Kanda, K. Kohama, M. Takahashi, K. Itoh
Collaborative Conference on 3D and Materials Research 2015, 15-19 June 2015, Busan, South Korea.

5.

"Development of DLC cone for fast ignition experiment"
Mayuko Koga, Takuma Ono, Takuma Tokunaga, Hayato Kadota, Takashi Hashimoto, Kazuhiro Kanda,
Takayoshi Norimatsu
9th International Conference on Reactive Plasmas (ICRP-9) October 12-16, 2015.

6.

"Double Crystal Monochromator Controlled by Integrated Computing on BL07A in New
SUBARU, Japan"
Masato Okui, Naoki Yato, Akinobu Watanabe, Baiming Lin, Norio Murayama, Sei Fukushima andKazuhiro Kanda
12th International Conference on Synchrotron Radiation Instrumentation(SRI2015) July 6-10, 2015,
Marriott Marquis Times Square New York City, NY United States.

7.

"Continuous Generation of Laser Plasma x-ray using Solid Rare Gas Targets"
S.AmanoThe 4th Advanced Lasers and Photon Source Conference (ALPS’15), Yokohama, Apri.22-24, 2015.

8.

"Anatase TiO2 Thin Films Grown by Facing-Target Reactive Sputtering and Its Impact on
Photocatalytic Activity"
Retsuo Kawakami, Masahito Niibe, Yoshitaka Nakano, Chisato Azuma and Takashi Mukai
Proceedings of International Symposium of Dry Process 2015, pp.125--126, Nov. 2015, Awaji Japan.

9.

"A Relation between Pinch-Off Voltages and Deep-Level Defects in AlGaN/GaN
Hetero-Structures Treated by CF4 Plasma"
Yoshitaka Nakano, Retsuo Kawakami, Masahito Niibe, Tatsuo Shirahama and Takashi Mukai
11th International Conference on Nitride Semiconductors (ICNS-11), Beijing, Sep. 2015.

1112

10. "Low energy soft X-ray Emission Spectrometer at BL-09A in NewSUBARU"
Masahito Niibe and Takashi Tokushima
The 12th inter’l conf. on Synchrotron Radiation Instrumentation (SRI2015) 6-10 July 2015, New York,USA.
11. "Development of the Surface-sensitive Soft X-ray Absorption Fine Structure Measurement
Technique for the Bulk Insulator"
Takumi Yonemura, Junji Iihara, Shigeaki Uemura, Koji Yamaguchi, Masahito Niibe
The 12th inter’l conf. on Synchrotron Radiation Instrumentation (SRI2015) 6-10 July 2015, New York,USA.
12. "Comparison between Surface Characteristics of Titanium Oxide Thin Films Treated with N2
Dielectric Barrier Discharge Plasma and Annealed in N2 Gas"
Retsuo Kawakami, Masahito Niibe, Yoshitaka Nakano and Takashi Mukai
Proc. 13th International Symposium of Sputtering & Plasma Processes (ISSP), pp.63--66, Kyoto, Jul.
2015.
13. "Temperature dependence of molecular orientation of liquid crystalline polymer induced bynanoimprint-graphoepitaxy"
M. Okada, Y. Haruyama, S. Matsui, R. Hosoda, Y. Taniguchi, N. Kawatsuki and H. Ono
59th International Conference on electron, ion, photon beam technology and fabrication(EIPBN2015),
San Diego, USA, 2015/5/27
14. "Upgrade of a Vacuum Ultraviolet and Soft X-ray Undulator Beamline BL07B in NewSUBARU"
Y. Haruyama and S. Matsui
12th International Conference on Synchrotron Radiation Instrumentation (SRI 2015), Newyork, USA,
2015/7/7
15. "Surface Evaluation of HSQ containing PDMS Additive after Room-temperature
Nanoimprinting"N. Sugano, M. Okada, Y. Haruyama, and S. Matsui
32nd International Conference of Photopolymer Science and Technology(ICPST-32), Chiba, Japan,
2015/7/25
16. "Toward Less Than 50 nm-Line and Space Negative Tone Pattern Fabrication by Electron Beam
Lithography using NEB-22"
M. Okada and S. Matsui
41th International Conference on Micro and Nano Engineering (MNE2015), The Netherlands, 2015/9/22
17. "Localized liquid crystalline molecular orientation in line and space pattern fabricated by double
nanoimprint-graphoepitaxy"
M. Okada, Y. Taniguchi, Y. Haruyama, H. Ono, N. Kawatsuki, and S. Matsui
41th International Conference on Micro and Nano Engineering (MNE2015), The Netherlands, 2015/9/23
18. "Negative tone high resolution line and space pattern mold fabrication by electron beamlithography using NEB-22"
M. Okada and S. Matsui
The 14th International Conference on Nanoimprint and Nanoprint Technology 2015 (NNT2015), Napa,
USA, 10/23

2113

19. "Double nanoimprint-graphoepitaxy for localized liquid crystalline molecular orientation in
imprinted pattern"
M. Okada, Y. Taniguchi, Y. Haruyama, H. Ono, N. Kawatsuki, and S. Matsui
The 14th International Conference on Nanoimprint and Nanoprint Technology 2015 (NNT2015), Napa,
USA, 10/23
20. "Resin Concentration Dependence of Residual Layer Thickness in UV Reversal Nanoimprinting"N. Sugano, M. Okada, Y. Haruyama and S. Matsui
28th International Microprocesses and Nanotechnology Conference (MNC2015), Toyama, Japan,
2015/11/12
21. "Negative Tone 40 nm-Line and 60 nm-Space Pattern Fabrication by Electron Beam Lithography
Using NEB-22"
M. Okada and S. Matsui
28th International Microprocesses and Nanotechnology Conference (MNC2015), Toyama, Japan,
2015/11/12
22. "Study of the Durability of Antisticking Layer against Repeated Ultra Violet Nanoimprinting"
S. Iyoshi, M. Okada, Y. Haruyama and S. Matsui
28th International Microprocesses and Nanotechnology Conference (MNC2015), Toyama, Japan,
2015/11/13
23. "Evaluation of Molecular Orientation of Photo-Cross-Linkable Liquid Crystalline Polymer in 200
nm-Line and Space Pattern by Measuring Diffraction Efficiency"
M. Okada, Y. Taniguchi, Y. Haruyama, H. Ono, N. Kawatsuki, and S. Matsui
28th International Microprocesses and Nanotechnology Conference (MNC2015), Toyama, Japan,
2015/11/13
24. "Observation Result of Actual Phase Defects on an EUV Mask Using Micro Coherent EUV
Scatterometry Microscope"
H. Hashimoto, T. Harada, T. Amano, H. Kinoshita and T. Watanabe
Micronano conference 2015, Toyama, Japan, Nov.10-13, 2015.
25. "Measurement Result of an EUV Collector Mirror Using a Large Reflectometer at
NewSUBARU"
H. Iguchi, H. Hashimoto, M. Kuki, T. Harada, H. Kinoshita, T. Watanabe, Y.Y. Platonov, M.D. Kriese
and J.R. Rodriguez
Micronano conference 2015, Toyama, Japan, Nov.10-13, 2015.
26. "Soft X-ray Absorption Spectroscopy using SR for EUV Resist Chemical Reaction Analysis(Invited talk) "Takeo Watanabe
TWG EUV Ressit Workshop, Maastricht, Netherland, Oct. 4, 2015.
27. "Extreme ultraviolet mask observations using a coherent extreme ultraviolet scatterometry
microscope with a high-harmonic-generation source"
Takahiro Fujino, Yusuke Tanaka, Tetsuo Harada, Yutaka Nagata, Takeo Watanabe, Hiroo Kinoshita
Photomask Technology 2015, Monterey, USA, 2015/9/29.

3114

28. "Development of Transmission Grating for EUV Interference Lithography of 1X nm HP"
Tsubasa Fukui, Hirohito Tanino, Yuki Fukuda, Masaki Kuki, Takeo Watanabe, Hiroo Kinoshita, andTetsuo Harada
The 32nd International Conference of Photopolymer Science and Technology, Makuhari Messe, Chiba,
Japan, June 24 - 26, 2015.
29. "Development of High-Reflective W/Si-multilayer Diffraction Grating for the Analysis of Fluorine
Materials"
Masaki Kuki, Tomoyuki Uemura, Masato Yamaguchi, Tetsuo Harada, Takeo Watanabe, Yasuji
Muramatsu, and Hiroo Kinoshita
The 32nd International Conference of Photopolymer Science and Technology, Makuhari Messe, Chiba,
Japan, June 24 - 26, 2015.
30. "Recent Progress in EUV Resist Outgas Research at EIDEC"
Eishi Shiobara, Isamu Takagi, Yukiko Kikuchi, Takeshi Sasami, Shinya Minegishi, Toru Fujimori, Takeo
Watanabe, Tetsuo Harada, Hiroo Kinoshita, and Soichi Inoue
The 32nd International Conference of Photopolymer Science and Technology, Makuhari Messe, Chiba,
Japan, June 24 - 26, 2015.
31. "Effective EUV Resist Outgassing Barrier Using a Novel Top Coat Material"
Xiaowei Wang, Georg Pawlowski, Tetsuo Okayasu, Masato Suzuki, Yusuke Hama, Takeo Watanabe,
Tetsuo Harada, and Hiroo Kinoshita
The 32nd International Conference of Photopolymer Science and Technology, Makuhari Messe, Chiba,
Japan, June 24 - 26, 2015.
32. "EUV resist outgassing analysis for the new platform resists at EIDEC"
Eishi Shiobara, Yukiko Kikuchi, Shinji Mikami, Takeshi Sasami, Takashi Kamizono, Shinya Minegishi,
Takakazu Kimoto, Toru Fujimori, Takeo Watanabe, Tetsuo Harada, Hiroo Kinoshita, Satoshi Tanaka
SPIE advanced Lithography 2016, San Jose USA, Feb. 23-24, 2016.
33. "FABRICATION OF TRANSMISSION GRATING OF EUV INTERFERENCE
LITHOGRAPHY FOR 1X NM HP EUV RESIST EVALUATION"
Takeo Watanabe, Tsubasa Fukui, Hirohito Tanino, Yuki Fukuda, Masaki Kuki, Masato Yamaguchi,
Tetsuo Harada
EUV International Symposium 2015, Masstricht, Netherland, Oct. 6-8, 2015.
34. "QUANTITATIVE PHASE-CONTRAST IMAGING OF A PHASE DEFECT USING ALENSLESS MICROSCOPE"
Tetsuo Harada, Hiraku Hashimoto, Tsuyoshi Amano, Hiroo Kinoshita, Takeo Watanabe
EUV International Symposium 2015, Masstricht, Netherland, Oct. 6-8, 2015.
35. "A Study of EUV Resist Sensitivity by Using Metal materials"
Atsushi Sekiguchi, Yoko Matsumoto, Tadashi Yamanouchi, Takeo Watanabe, Tetsuo Harada, Hiroto
Kudo
EUV International Symposium 2015, Masstricht, Netherland, Oct. 6-8, 2015.
36. "Comparison of EUV Resist Outgassing between Organic and Inorganic Materials"
Yukiko Kikuchi, Takeshi Sasami, Shinya Minegishi, Shinji Mikami, Takashi Kamizono, Toru Fujimori,Takeo Watanabe, Tetsuo Harada, Eishi Shiobara
EUV International Symposium 2015, Masstricht, Netherland, Oct. 6-8, 2015.

4115

37. "Phase Imaging Results of Phase Defect Using Micro Coherent EUV Scatterometry Microscope"
Tetsuo Harada, Hiraku Hashimoto, Tsuyoshi Amano, Hiroo Kinoshita, and Takeo Watanabe
Photomask Technology 2015, Monterey, USA, Sep.29 - Oct.1, 2015.
38. "Development of Micro Coherent EUV Scatterometry Microscope for Phase DefectCharacterization"
Hiraku Hashimoto, Yusuke Tanaka, Tetsuo Harada, Takeo Watanabe, Hiroo Kinoshita
Photomask Japan 2015, Yokohama, Japan, Apr. 20-22, 2015.
39. "Development of a reflectometer for a large EUV mirror in NewSUBARU"Haruki Iguchi, Hiraku Hashimoto, Masaki Kuki, Tetsuo Harada, Takeo Watanabe, and Hiroo Kinoshita
Photomask Japan 2015, Yokohama, Japan, Apr. 20-22, 2015.
40. "EUV mask observations using a coherent EUV scatterometry microscope with ahigh-harmonic-generation source"
Takahiro Fujino, Yusuke Tanaka, Tetsuo Harada, Yutaka Nagata, Takeo Watanabe, and Hiroo Kinoshita
Photomask Japan 2015, Yokohama, Japan, Apr. 20-22, 2015
41. "Fabrication of SERS Active Noble Metallic Nanostructure by Synchrotron Radiation Induced
Photochemical Reaction"
T. Matsumoto, I. Okada, I. Sakurai, Y. Utsumi and A. YamaguchiInternational Conference on Electronics Packaging (ICEP2015), April 14-17 (2015), Kyoto, Japan
42. "Fabrication and evaluation of dihedral corner reflector array for floating image manufactured bysynchrotron radiation"
T. Yamane, S. Maekawa, Y. Utsumi, I. Okada and A. YamaguchiInternational Conference on Electronics Packaging (ICEP2015), April 14-17 (2015), Kyoto, Japan
43. "Application of Gold Nanoparticles Self-assemblies to Unclonable Anti-counterfeiting Technology"
T. Fukuoka, A. Yamaguchi, R. Hara, T. Matsumoto, Y. Utsumi and Y. MoriInternational Conference on Electronics Packaging (ICEP2015), April 14-17 (2015), Kyoto, Japan
44. "Optofluidicdevices implemented 3D gold nanostructure enabling surface enhanced Raman
scattering"
Akinobu Yamaguchi, Takao Fukuoka, Ryo Takahashi, and Yuichi Utsumi
The International Chemical Congress of Pacific Basin Societies 2015, December 15-20 (2015), Honolulu,
Hawaii, USA
45. "SERS active gold nanostructure by synchrotron radiation induced photochemical reaction"
Takeshi Matsumoto, Ikuo Okada, Ikuya Sakurai, Yuichi Utsumi, Akinobu Yamaguchi
The International Chemical Congress of Pacific Basin Societies 2015, December 15-20 (2015), Honolulu,
Hawaii, USA
46. "Surface enhanced Raman scattering sensing using a coffee-ring-type 3D silver nanostructureself-assembled on glass substrates"
Akinobu Yamaguchi, Takao Fukuoka, Ryohei Hara, Yuichi Utsumi
The International Chemical Congress of Pacific Basin Societies 2015, December 15-20 (2015), Honolulu,
Hawaii, USA

5116

47. "Gold nanoparticle self-assemblies for on-dose-authentication of medical tablets"
Takao Fukuoka, Akinobu Yamaguchi, Yuichi Utsumi, Yasushige MoriThe International Chemical Congress of Pacific Basin Societies 2015, December 15-20 (2015), Honolulu,
Hawaii, USA
48. "Sterically-bulky self assemblies of gold nanoparticles"
Takao Fukuoka, Ryo Takahashi, Yuichi Utsumi, Akinobu Yamaguchi
The International Chemical Congress of Pacific Basin Societies 2015, December 15-20 (2015), Honolulu,
Hawaii, USA
49. "Fundamental study of a microwave irradiation structure using transparent post-wall waveguide"
Mitsuyoshi Kishihara, Yasuhito Minamiyama, Akinobu Yamaguchi, Yuichi Utsumi
The International Chemical Congress of Pacific Basin Societies 2015, December 15-20 (2015), Honolulu,
Hawaii, USA

6117

(3) Academic degrees
1. Master of Engineering
Shodai Hirai (University of Hyogo)"Surface analysis of AlGaN films etched with Ar, CF4 and UV-assisted CF4 plasmas"
Tsubasa Fukui (University of Hyogo)
10 nm 領域の EUV 干渉露光用透過型回折格子の製作"Fabrication of an EUV interference-lithography grating for 1x-nm pattern replication"
Masato Yamaguchi (University of Hyogo)
軟 X 線吸収分光法による EUV フォトレジスト分析手法の開発"Chemical reaction analysis of EUV photoresist using soft x-ray absorption spectroscopy"
Hirohito Tanino (University of Hyogo)
EUV 干渉露光装置の高度化"Improvement of EUV interference-lithography system"
Takahiro Fujino (University of Hyogo)
高次高調波を用いた回折顕微鏡による EUV マスクの欠陥観察手法の開発"Defect observation of EUV mask using an EUV diffraction microscope with a high harmonic generation EUV
source"Masaki Kuki (University of Hyogo)
500〜1,100 eV 領域用の高反射 W/Si 多層膜回折格子の開発"Development of a high-reflective W/Si-multilayer coating on a diffraction grating for 500 - 1,100 eV region"
Takeshi Matsumoto (University of Hyogo)"Study on detection of mouse IgG through ELISA using Lab-on-a-CD"
Motoki Murakami (University of Hyogo)"Study on fabrication of microfluidic chip and micro-total analysis system made of PTFE"
2. Master of Science
Karin Kobayashi (University of Hyogo)"Study of LEENA Electron Beam Monitor and Tuning of Accelerator"
Takuya Matsumoto (University of Hyogo)"Simulation Study of Laser Compton Gamma-ray Beam Source"
Norihiro Sugano (University of Hyogo)"ナノインプリント用 PDMS 離型剤含有 HSQ レプリカモールドに関する研究"

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LASTI Annual Report Vol.17 (2015)________________________________________________________
September 2016, Published byLaboratory of Advanced Science and Technology for Industry
University of Hyogo
3-1-2 Kouto, Kamigori-Cho, Ako-gun, Hyogo 678-1205, JAPAN
Phone: +81-791-58-0249 / FAX: +81-791-58-0242
Editorial board
NIIBE Masahito (Editor in Chief)
SHOJI Yoshihiko
HARUYAMA Yuichi
YAMAGUCHI Akinobu
HARADA Tetsuo______________________________________________________________