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Current Status ofLight Sources and Beamlines

Ⅱ Current Status of Light Sources and Beamlines

Light Source in 2022
Yoshitaka TairaUVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, JapanIn FY2022, UVSOR-III was operated for users asscheduled for 36 weeks from end of May 2022 toMarch 2023. Monthly statistics of operation time andintegrated beam current are shown in Fig. 1. From April
1 to May 6 was a shutdown period, during which
periodic inspections were conducted. The two weeks
following the shutdown were allocated to the adjustmentof the accelerator and beamlines.
The weekly operation schedule is as follows.
Mondays are assigned to machine studies from 9:00
AM to 9:00 PM. User operation is assigned Tuesday
through Friday, with Tuesday and Wednesday operatingfrom 9:00 AM to 9:00 PM, and Thursday from 9:00
AM to 9:00 PM on Friday for 36 continuous hours.
Thus, the user’s beam time per week is 60 hours.
July to August is the period when attention should be
paid to instantaneous voltage drops caused by lightning
strikes. Beam dumps due to instantaneous voltage
drops occurred frequently, resulting in loss of operation
time. High voltage application errors in the klystronpulse modulator had been occurring since the fall of
2021 and were still occurring frequently in 2022. The
cause of this event is unknown, but it is not occurring
now. It is possible that the error was corrected
accidentally during an inspection. Regarding vacuumrelated issues, vacuum leakage from the bellows ductof the bending magnet of the booster synchrotron has
occurred frequently. The vacuum level has deteriorated
due to the formation of pinholes in the ducts, but thishas been addressed each time by applying repair
materials. Failures of the beam position monitor moduleand the RF frequency signal generator were addressedby replacing them with alternatives or repairing them.
APPLE-II type tandem undulators are in operational
at BL1U. Until now, they were used only on machine
study days as the standard orbit of the electron beam foruser operation did not pass through the central axis ofthese undulators. From April 2022, the standard orbit
has been changed to one that passed through the center
axis. This improvement allows some users to conduct
experiments on the BL1U undulators during normaluser operation.
We started a design study for the future plan of
UVSOR-IV. As a first step, we have analyzed thepresent magnetic lattice, seeking a possibility to reduce
the emittance more [1]. Although, we did not find asolution to drastically reduce emittance, we have founda few interesting solutions that achieved lower
emittance than the current situation. As the second step,
we have started designing a totally new storage ring,which is close to the diﬀraction limit in the VUV range[2].
The steep rise in electricity prices is a global problem.
Although the rate of increase in electricity prices inJapan is lower than in Europe, the impact is stillenormous. UVSOR’s electricity rates typically range
between 50 - 60 million yen per year, but the estimatedamount for FY2022 is over 80 million yen. The power
consumption of the electron accelerator and beamline
during non-operating periods is 50 kW and 150 kW,
respectively. These are mainly the power used tomaintain a high vacuum, such as vacuum pumps.
During accelerator operation, these increase to 390 kW
and 250 kW, respectively. As power saving measures,
we have begun shortening operation hours outside ofnormal user operation, such as weekend operation,
turning oﬀ unused equipment, and shutting down
vacuum pumps at beamlines with low user utilization.
The light source development and utilization
beamline BL1U, constructed under the support ofQuantum Beam Technology Program by MEXT/JST,
continue to develop new light source technologies andtheir applications such as free electron laser, coherent
harmonic generation, coherent synchrotron radiation,
coherent control [3], laser Compton scattered gamma
rays [4], and optical vortices.

Fig. 1. Monthly statistics in FY2022.
[1] E. Salehi and M. Katoh, Proceedings of IPAC2021(2021) 3970.
[2] E Salehi, Y Taira, M Fujimoto, L Guo, M. Katoh, J.
Phys.: Conf. Ser. 2420 (2023) 012062.
[3] T. Kaneyasu et al., Sci. Rep. 13 (2023) 6142.
[4] Y. Taira et al., Rev. Sci. Instr. 93 (2022) 113304.

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− 12 −

Ⅱ Current Status of Light Sources and Beamlines− 13 −

Beamlines in 2022
Fumihiko Matsui
UVSOR Synchrotron Facility, Institute for Molecular Science

UVSOR is one of the highest-brilliance light sourcesin the extreme-ultraviolet region among the synchrotron
radiation facilities with electron energies of less than 1
GeV. The low natural emittance of the UVSOR-III
storage ring, 17.5 nm-rad, was accomplished after the
successful completion of the storage ring upgrade
project (the UVSOR-III project) in 2012. Eight bending
magnets and six insertion devices are available assynchrotron light sources at UVSOR. There are a totalof fourteen operational beamlines. Twelve of them are
the so-called “Public beamlines”, which are open toscientists from universities and research institutes
belonging to the government, public organizations,private enterprises and also those from foreigncountries. The beamline BL6U is the “In-housebeamlines”, and are dedicated to the use of researchgroups within Institute for Molecular Science (IMS).
The beamline BL1U is a partially “Public” and partially“In-house” beamline. There is one tender X-ray (TX)
station equipped with a double-crystal monochromator,
seven extreme ultraviolet (EUV) and soft X-ray (SX)
stations with grazing incidence monochromators, threevacuum ultraviolet (VUV) stations with normal
incidence monochromators, two infrared (IR) stations
equipped with Fourier Transform interferometers, andone direct radiation station located after two tandem
undulators, as shown in the appended table (next page)for all available beamlines at UVSOR in 2022. The
details of the updates for undulator beamlines are thefollowings.
● In BL1U, the development of a new light source
and the utilization of gamma-rays are being carriedout. This beamline is equipped with a tandem
undulators with a buncher section, which can beused for free electron laser in the range fromvisible to deep UV, VUV coherent harmonic
generation, and generation of spatiotemporal
structured light such as an optical vortex beam, avector beam and double-pulsed wave packets.
It is also equipped with a femto-second laser
system synchronized with the accelerator, which
is used for the generation of Compton scatteredgamma-rays. Users are provided with gamma-ray
induced positron annihilation spectroscopy that
can analyze nanometer-order defects in bulk
materials. To increase the counting rate ofannihilation gamma rays, an array detector witheight BaF2 scintillators was developed. The
measurement can be completed in a few hours formetal samples.
● In BL3U, the ultrathin-liquid cell for low-energy
XAS has been developed. The studies of local
structures of several aqueous solutions and various
chemical processes in solution such as catalytic

●

●

●

− 14 −and electrochemical reactions, and laminar flows
in microfluidics by using operando XAS in C, N,
and O K-edges were demonstrated. Moreover, anargon gas window that is eﬀective from 60 to 240
eV with the removal of high-order X-rays, which
will develop chemical research since it includes
K-edges of Li and B and L-edges of Si, P, S, andCl was established.
Resonant soft X-ray scattering (RSoXS) for soft
materials is also applicable. RSoXS is similar tosmall angle X-ray scattering (SAXS) and canprovide information on the mesoscopic structure(1-100nm) of sample. This method has selectivityof elements, functional groups and molecularorientation. Since soft X-ray region include K—edge energies of light element (C, N, O), RSoXS
is a powerful tool to investigate soft matters.
BL4U, which is equipped with a scanningtransmission soft X-ray microscope (STXM), is
actively used not only by academic users but also
by many industrial users. The STXM can beapplied to wide range of sciences, such as polymer
science, material science, cell biology,
environmental science, and so on. In FY2020, it
became possible to image the lithium K-edge witha spatial resolution of 72 nm. Final adjustments
for the airtight sample transport system and thesample transport container were carried out for theorganic substance analysis of the Hayabusa2
returned samples for the summer of FY2021.
In BL5U, high energy resolution angle-resolved
photoemission spectroscopy (ARPES) is available.
Users can now use so-called “deflector mapping”
for all kinetic energies and lens modes by using
the latest version of ARPES analyzer. Users canalso obtain spatial-dependence of the electronic
structure of solid surfaces using micro-focused
beam (50 μm). An alkali-metal deposition system
has been installed. Potassium for example can bedeposited while the sample is still mounted on the
manipulator at low temperatures. As part of thedevelopment of spin-resolved ARPES, a twodimensional image of the spin-resolved spectrumof the Rashba splitting of Au(111) surface has
been successfully obtained.
At BL6U, one of the In-house beamlines,
photoelectron momentum microscope (PMM),
which is a new-concept multi-modal electronic
structure analysis system with high resolution inreal space and momentum space, has been installed
and is in operation. A key feature of the PMM isthat it can very eﬀectively reduce radiationinduced damage by directly projecting a single
photoelectron constant energy contour inⅡ Current Status of Light Sources and Beamlines●

reciprocal space with a radius of a few Å-1 or real
space with a radius of a few hundred μm onto a 2D
detector. Experiments such as valence band
photoelectron spectroscopy on the micrometerscale and resonance photoelectron diﬀraction bysoft X-ray excitation are performed. In FY2023,
we plan to further expand PMM’s capabilities byintroducing an additional 2D spin filter. In addition
to grazing-incidence soft X-ray excitation, normalincidence vacuum ultraviolet (VUV) beam withvariablepolarizations(horizontal/vertical/
circular) became also available at the same focal
position of the PMM via a newly added branchfrom the next BL7U. This highly symmetricalmeasurement geometry completely eliminates thep-polarized linear dichroism eﬀect in the circulardichroism measurements of valence band, making
transition matrix element analysis much simpler
and reliable.
At BL7U, high-energy resolution ARPES isavailable with extremely low energy of photons (6eV~) using the low-temperature 6-axis manipulator
with a sample temperature 4.5-350 K. In FY2021,
the deflector-type detector for the hemisphericalanalyzer was installed to realize an eﬀective 2D
measurement with the automated manipulator
control. Users can perform the measurement of thebulk sensitive electronic structure of solids and thehigh-throughput measurement for molecularmaterials using high-photoionization cross-section
using low-excitation photon energy.
Those wishing to use the open and in-house beamlines
are recommended to contact the appropriate beamline
contact persons (see next page). Applications can besubmitted at NOUS (https:// nous.nins.jp/user/signin).
All users are required to refer to the beamline manuals
and the UVSOR guidebook, on the occasion of
conducting the actual experimental procedures. For
updated information on UVSOR, please see http://
www. uvsor.ims.ac.jp.

− 15 −

Beamlines at UVSOR
Beamline
BL1U

Monochromator /Spectrometer

Energy Range

Targets

Techniques(Irradiation)

Y. Taira

Solid

Reflection
Absorption

K. Tanaka

Solid

Reflection
Absorption

F. Matsui

Solid

Photoemission

S. KeraGas
LiquidSolid

Absorption
Photoemission
Photon-emission
Reflection
Absorption
Photon-emission

Free electron laser

1.6 – 13.9 eV
BL1B

Martin-Puplett FT-FIR

0.5 – 30 meV
BL2A

Double crystal

585 – 4 keV
18-m spherical grating(Dragon)

BL2B

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

BL3U

BL3B

23 – 205 eV

40 – 800 eV

2.5-m off-plane Eagle

Solid

1.7 – 31 eV
Varied-line-spacing
plane grating(Monk-Gillieson)
Varied-line-spacing
plane grating(Monk-Gillieson)

BL4U

BL4B

Spherical grating(SGM-TRAIN†)

BL5U

BL5B

50 – 770 eV

25 eV – 1 keVVariable-included-angle
varied-line-spacing
plane grating

BL6B

40 – 500 eVMichelson FT-IR
10-m normal incidence(modified Wadsworth)

BL7B

Yellow columns represent undulator beamlines.
In-house beamline.

*− 16 −

H. Iwayama
iwayama@ims.ac.jp

F. Matsui
matui@ims.ac.jp

Photoionization
Photodissociation
Photoemission

H. Iwayama

Solid

Photoemission

K. Tanaka

Solid

Calibration
Absorption

K. Tanaka

Gas
Solid

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

iwayama@ims.ac.jp

k-tanaka@ims.ac.jp

k-tanaka@ims.ac.jp

F. Matsui
matui@ims.ac.jp

K. Tanaka
k-tanaka@ims.ac.jp

Solid

Photoemission

K. Tanaka

Solid

Reflection
Absorption
Photon-emission

F. Matsui

6 – 40 eV

1.2 – 25 eV

kera@ims.ac.jp

Gas
Solid

Solid

3-m normal incidence

matui@ims.ac.jp

T. Ohigashi

4 meV – 2.5 eV
BL7Uk-tanaka@ims.ac.jp

Absorption(Microscopy)

6 – 600 eV
BL6U*

yostaira@ims.ac.jp

Gas
LiquidSolid

20 – 200 eV

Plane grating

Contact

k-tanaka@ims.ac.jp

matui@ims.ac.jp

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

Fig. 1. Configuration of the free electron laser

VerticalCircular

Horizontal

Fig. 2. Brilliance of BL1U Apple-II Undulator

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

Wave Length

Wave Length

800 nmPulse Length

130 fsec

199-800 nm-4Spectral Band Width~10

Polarization

Circular/Linear

Oscillator

90.1 MHz

Pulse Rate

11.26 MHz

Pulse Energy

2.5 mJ

10 mJ

50 mJ

Max. Ave. Power~1 W

Repetition Rate

1 kHz

1 kHz

10 Hz

− 17 −

BL1B
Terahertz Spectroscopy Using Coherent Synchrotron Radiation▼Description
Coherent synchrotron radiation (CSR) is a powerful light source in the terahertz (THz) region. This beamline has
been constructed for basic studies on the properties of THz-CSR. However, it can be also used for measurements ofreflectivity and transmission spectra of solids using conventional synchrotron radiation.
The emitted THz light is collected by a three-dimensional magic mirror (3D-MM, M0) of the same type as thosealready successfully installed at BL43IR in SPring-8 and BL6B in UVSOR-II. The 3D-MM was installed in bendingmagnet chamber #1 and is controlled by a 5-axis pulse motor stage (x, z translation; θx, θy, θz rotation). The acceptanceangle was set at 17.5-34 degrees (total 288 mrad) in the horizontal direction. The vertical angle was set at ±40 mrad
to collect the widely expanded THz-CSR.
The beamline is equipped with a Martin-Puplett type interferometer (JASCO FARIS-1) to cover the THz spectral
region from 4 to 240 cm-1 (hν = 500 μeV-30 meV). There is a reflection/absorption spectroscopy (RAS) end-station
for large samples (~ several mm). At the RAS end-station, a liquid-helium-flow type cryostat with a minimum
temperature of 4 K is installed.

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

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

▼Technical Data
Interferometer

Martin-Puplett (JASCO FARIS-1)

Wavenumber range(Energy range)

4-240 cm-1
(500 PeV-30 meV)

Resolution in cm-1

0.25 cm-1

Experiments

Reflection/transmission spectroscopy

Miscellaneous

Users can use their experimental system in this beamline.

− 18 −

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

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

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

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

− 19 −

BL2B
Photoelectron spectroscopy of molecular solids▼Description
This beamline previously dedicated for experiments in the field of gas phase photoionization and reaction
dynamics. Then, the beamline has been reconstructed for photoelectron spectroscopy of molecular solids with a newend station, and experiments can be performed from May 2014. The monochromator is a spherical grating Dragon
type with 18-m focal length. High throughput (1 × 1010 photons s-1) and high resolution (E/∆E = 2000 - 8000) areachieved simultaneously under the condition of the ring current of 100 mA [1]. The optical system consists of two
pre-focusing mirrors, an entrance slit, three spherical gratings (G1 - G3), two folding mirrors, a movable exit slit,
and a refocusing mirror [2]. The monochromator is designed to cover the energy range of 23–205 eV with the threegratings: G1 (2400 lines mm-1, R = 18 m) at 80–205 eV; G2 (1200 lines mm-1, R = 18 m) at 40–100 eV; G3 (2400lines mm-1, R = 9.25 m) at 23–50 eV. The percentage of the second-order light contamination at hν = 45.6 eV is
23 % for G2 or 7 % for G3.
A UHV chamber is placed downstream of the refocusing mirror chamber and equipped silicon photodiode,sapphire plate Au mesh and filters for absolute photon flux measurement, monitor the photon-beam position, relative
photon flux measurements and attenuate higher order light, respectively.
The new end station consists of a main chamber with a hemispherical analyzer (SCIENTA R3000) and a liquidHe-cooled cryostat (temperature range of 15-400 K) with 5-axis stage, a sample preparation chamber with a fastentry load-lock chamber and a cleaning chamber with LEED, ion gun for sputtering and IR heating unit.
[1] M. Ono, H. Yoshida, H. Hattori and K. Mitsuke, Nucl. Instrum. Meth. Phys. Res. A 467-468 (2001) 577.
[2] H. Yoshida and K. Mitsuke, J. Synchrotron Radiation 5 (1998) 774.

Fig. 2. End station of BL2B for photoelectron
spectroscopy of molecular solids.
Fig. 1. Throughput from Dragon monochromator.

▼Technical Data
Monochromator

18 m spherical grating Dragon-type

Wavelength Range

23-205 eVResolution

2000–8000 depending on the gratings

Experiments

Angle-resolved ultraviolet photoelectron spectroscopy− 20 −

BL3U
Varied-Line-Spacing Plane Grating Monochromatorfor Molecular Soft X-Ray Spectroscopy▼Description
The beamline BL3U is equipped with an in-vacuum undulator composed of 50 periods of 3.8 cm period length.
The emitted photons are monochromatized by the varied-line-spacing plane grating monochromator (VLS-PGM)
designed for various spectroscopic investigations in the soft X-ray range. Three holographically ruled laminar
profile plane gratings are designed to cover the photon energy range from 40 to 800 eV. The beamline has liquid cells
for soft X-ray absorption spectroscopy (XAS) in transmission mode as shown in Fig. 1. The liquid cell is in theatmospheric helium condition, which is separated by a 100 nm thick Si3N4 membrane with the window size of
0.2 × 0.2 mm2 from the beamline in an ultrahigh vacuum condition. The thin liquid layer is assembled by using two
100 nm thick Si3N4 membranes. The thickness of the liquid layer is controllable from 20 to 2000 nm by adjusting
the helium pressures around the liquid cell in order to transmit soft X-rays. Liquid samples are exchangeable in situ
by using a tubing pump. The liquid cell has two types of windows: one is the liquid part to obtain the soft X-ray
transmission of liquid (I), and the other is the blank part to obtain the transmission without liquid (I0). We can obtain
the reliable XAS spectra based on the Lambert-Beer law ln(I0/I). Since the liquid cell is in the atmospheric condition,
we can measure XAS of liquid samples in the real environment. Operando XAS observation of several chemical
reactions such as catalytic, electrochemical reactions are also possible by using our liquid cells developed for these
purposes.

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

▼Technical Data
Monochromator
Energy Range
Resolution
Experiments

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

− 21 −

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

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

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

▼Technical Data
Monochromator-2.5 m normal-incidence monochromator

Energy range

1.7-31 eV (40~730 nm)

Resolution ('hQ/ hQ)

t 12000 (at ~ 6.9 eV, 0.02 mm slits, G1 (1200 l/mm)

Experiments

Photoluminescence, reflection, and absorption spectroscopy, mainly for solids− 22 −

BL4U
Scanning Transmission X-ray Microscopy in the Soft X-ray Region▼Description
In the soft x-ray region, there are several absorption edges of light elements and transition metals. The near edge
X-ray absorption fine structure (NEXAFS) brings detailed information about the chemical state of target elements.
A scanning transmission X-ray microscope (STXM) in the soft X-ray region is a kind of extended technique of the
NEXAFS with high spatial resolution. The STXM has a capability of several additional options, for example, in-situ
observations, 3-dimensional observation by computed tomography and ptychography, by utilizing the characteristicsof the X-rays. The STXM can be applied to several sciences, such as polymer science, material science, cell biology,
environmental science, and so on.
This beamline equips an in-vacuum undulator, a varied-line-spacing plane grating monochromator and a fixed exit
slit. The soft X-ray energy range from 50 to 770 eV with the resolving power (E/∆E) of 6,000 is available. The
aperture size of the fixed exit slit determines not only the resolving power but also the size of a microprobe. A
Fresnel zone plate is used as a focusing optical device through an order select aperture and its focal spot size of ~30
nm is available at minimum. An image is acquired by detecting intensities of the transmitted X-rays by aphotomultiplier tube with scintillator with scanning a sample 2-dimensionally. By changing the energy of theincident beam, each 2-dimensional NEXAFS image is stacked. A main chamber of STXM is separated from thebeamline optics by a silicon nitride membrane of 50-nm thickness; therefore, sample folders can be handled in
vacuum or in helium.
M1 mirror andGratingPinholeSlit

M2 mirror

M0 mirror

Fixed exit slit

STXM

Fig. 1. Schematic image of BL4U

Fresnel zone plate
Order Sorting Aperture
SamplePhoto multiplier tube
with scintillator P-43

Monochromatized X-rays

Central stopper

Fig. 2. Schematic image of STXM

▼Technical Data
Energy range (E)50 -770 eVResolving power (E/'E)~6,000

Photon flux on a sample (photons/s)~2u107 @400 eV

Focusing optical element

Fresnel zone plate

Spatial resolution~30 nmExperiments

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

Measurement environment− 23 −

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

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㻝㻱㻥

㻝㻱㻤
㻜

㻞㻜㻜

㻠㻜㻜

㻢㻜㻜

㻤㻜㻜

㻝㻜㻜㻜

㻝㻞㻜㻜

㻼㼔㼛㼠㼛㼚㻌㻱㼚㼑㼞㼓㼥㻌㻔㼑㼂㻕

Fig. 1. Throughput from the VLS-PGM monochromatoron BL4B.

Fig. 2. Photo of BL4B.

▼Technical Data
Monochromator

Varied-line-spacing Plane Grating Monochromator

Energy range

25-1000 eVResolution

E / ǻE > 5000 (at maximum)

Experiments

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

− 24 −

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

Fig. 1. Picture and photon flux of BL5U.

▼Technical Data (Expected Performance)
Light source

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

Monochromator

Monk-Gillieson VLS-PGM

Energy Range

20-200 eVResolution

hv/ ǻE > 10,000 for < 10 ȝm slits

Experiment

ARPES, Space-resolved ARPES, Spin-resolved ARPES

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

Beam spot size

23 (H) x 40 (V) μm

Main Instruments

Hemispherical photoelectron analyzer with deflector scan (MBS A-1
Lens#4),
Liq-He flow cryostat with 5-axis manipulator (3.8 K-350 K)− 25 −

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

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

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

▼Technical Data
Monochromator

Plane Grating Monochromator

Energy range

6-600 eV (2-200 nm)

Resolution

E / ǻE ~500

Experiments

Calibration of optical elements, reflection and absorption spectroscopy mainly
for solids− 26 −

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

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

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

1E13

3rd

1E12

5th

1st
1E11

DE 168q
DE 170q
DE 172q
DE 174q

1E10
1E9
1E8
1E7
30

100

Photon energy(eV)Fig. 1. Throughput spectra of the BL6U
monochromator at various included angles.

Fig. 2. Photograph of BL6U end station▼Technical Data
Monochromator

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

Energy range

40-500 eV(practical)

Resolution

E / ǻE > 10000 (at maximum)

Experiments

High-resolution soft X-ray spectroscopy (photoelectron spectroscopy for solid
surfaces)− 27 −

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

Reflection/absorption
end station

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

IR microscopy imaging(Jasco IRT-7100)

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

Fig. 1. Schematic top view of BL6B.

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

▼Technical Data
Interferometer

Michelson (Bruker Vertex70v)-1Michelson (Jasco FT/IR-6100)

Wavenumber Range(Energy range)

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

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

0.1 cm-1

0.5 cm-1

Experiments

Reflectivity and transmission
spectroscopy
THz Microspectroscopy

IR microscopy imaging (JASCO IRT-7000)
ATR spectroscopy− 28 −

BL7U (SAMRAI)
Angle-Resolved Photoemission of Solids in the VUV Region▼Description
Beamline 7U, named the Symmetry- And Momentum-Resolved electronic structure Analysis Instrument(SAMRAI) for functional materials, was constructed to provide a photon flux with high energy resolution and highflux mainly for high-resolution angle-resolved photoemission spectroscopy, so-called “ARPES”, of solids [1]. An
APPLE-II-type variable-polarization undulator is installed as the light source. The undulator can produce intense
VUV light with horizontal/vertical linear and right/left circular polarization. The undulator light is monochromatizedby a modified Wadsworth type monochromator with three gratings (10 m radius; 1200, 2400, and 3600 lines/mm
optimized at hv = 10, 20, and 33 eV). The energy resolution of the light (hv/Δhv) is more than 104 with a photon fluxof 1011-1012 ph/s or higher on samples in the entire energy region. The beamline has a photoemission end-stationequipped with a 200 mm-radius hemispherical photoelectron analyzer (MB Scientific AB, A-l analyzer) with awide-angle electron lens and a liquid-helium-cooled cryostat with 6-axis pulse motor control. The main function of
the beamline is to determine the electronic structure of solids and its temperature dependence in order to reveal theorigin of their physical properties.
[1] S. Kimura, T. Ito, M. Sakai, E. Nakamura, N. Kondo, K. Hayashi, T. Horigome, M. Hosaka, M. Katoh, T. Goto,
T. Ejima and K. Soda, Rev. Sci. Instrum. 81 (2010) 053104.

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

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

Monochromator

10 m normal-incidence monochromator (modified Wadsworth type)

Photon energy range

6 – 40 eV (Ȝ = 30 – 200 nm)

Resolution (hv/ǻhv)E / ǻE > 10000-50000

Photon flux on sample

t 1011-1012 ph/s (depending on hv)

Beam size on sample

200 (H) × 50 (V) ȝm2

Experiments

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

− 29 −

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

Fig. 1. Throughput spectra of BL7B measured using asilicon photodiode.

Fig. 2. Photo of BL7B.

▼Technical Data
Monochromator

3 m Normal-Incidence Monochromator

Wavelength Range

50-1000 nm (1.2-25 eV)Resolution

E / 'E = 4000-8000 for 0.01 mm slits

Experiments

Absorption, reflection, and fluorescence spectroscopy, mainly for solids− 30 −UVSOR User 1

UVSOR User 2