Ⅲ-5

Life, Earth andPlanetary Sciences

BL4UⅢ -5. Life, Earth and Planetary Sciences

BL4U

Hayabusa2 Returned Samples: Unique and Pristine Record of Solar System
Materials from Asteroid Ryugu
M. Ito1, N. Tomioka1, M. Uesugi2, A. Yamaguchi3,4, N. Imae3,4, N. Shirai5, T. Ohigashi4,6,
M. Kimura3, M-C, Liu7, R.C. Greenwood8, K. Uesugi2, A. Nakato9, K. Yogata9, H. Yuzawa6,
Y. Kodama15, A. Tsuchiyama10, M. Yasutake2, R. Findlay8, I.A. Franchi8, J.A. Malley8,
K.A. McCain7, N. Matsuda7, K.D. McKeegan7, K. Hirahara11, A. Takeuchi2, S. Sekimoto12,
I. Sakurai13, I. Okada13, Y. Karouji14, T. Yada9, M. Abe9, T. Usui9, S. Watanabe13
and Y. Tsuda4,91

JAMSTEC Kochi, 2JASRI/SPring-8, 3NIPR, 4SOKENDAI, 5Tokyo Met. Univ., 6UVSOR/IMS, 7UCLA, 8Open Univ.,
9
JAXA/ISAS, 10Ritsumeikan Univ., 11Osaka Univ., 12Kyoto Univ., 13Nagoya Univ., 14JAXA/JSEC, 15Toyo Corp.

The Hayabusa2 spacecraft successfully returned
surface materials from the C-type asteroid Ryugu to
Earth on December 6th, 2020. The sample capsulecontained a large number of small grains, collected fromtouchdown (TD) sites 1 and 2 on Ryugu, with a total
mass of ~5.4 g [1]. After initial characterization of thegrains by JAXA curation [1,2], eight Ryugu particles(~60 mg in total), four from Chamber A and four from
Chamber C, were allocated to the Phase2 curation
Kochi team (Ph2K). The principal goals of the research
are to elucidate the nature, origin, and evolutionary
history of asteroid Ryugu, and to document thesimilarities to and/or differences from other known
extraterrestrial samples, such as chondritic meteorites,
interplanetary dust particles and returned cometary
samples collected by the NASA Stardust mission.
The coordinated micro-analysis work involved theuse of a wide range of multi-beam instruments to acquiredetailed micro-textural and chemical information about
the samples at a sub-micrometer scale using a
combination of FIB, STXM-NEXAFS, NanoSIMS andTEM [4,5]. In parallel, we conducted bulk systematic
analysis of the samples using SEM-EDS, EPMA, XRD,
large geometry type SIMS, high precision O isotopic
analysis by laser fluorination and INAA [4-8].
Using a combination of STXM-NEXAFS –NanoSIMS – TEM techniques, we have been able toestablish the spatial distribution of organics with an
aliphatic-rich carbon structure that are associated withphyllosilicates at sub-micrometer scale in the C006825 FIB section (Fig. 1).
C-NEXAFS spectra in the C0068-25 section show avariety of functional groups of aromatic (or C=C),
C=O, C-H or aliphatic, and C(=O)O, without 1s-σ*
exciton of graphene structures (Fig. 1(A)). Figure 1(B)shows the spatial distribution of carbon in the section.
In Fig. 1(C), three representative areas of aromatic (orC=C)-rich organics can be seen in red, aliphatic-richcarbon is shown in green and matrix in blue. Areas
with an intense aliphatic-rich carbon structure (green
area in Fig. 1(C)) are present locally in coarse-grained
phyllosilicates in the section (Fig. 1(D)), as well as
areas with a poorly aromatic (C=C) carbon structure.

The distribution of organics with an aliphatic carbon
structure may vary significantly depending on theexistence of coarse-grained phyllosilicates. The CNEXAFS revealed that the organics in the Ryugu
particles are chemically distinct from the previously
studied IOM of the Murchison CM chondrite [8]andshow greater similarity to IDPs [9] and cometary
particles obtained by the Stardust mission [10].
A question that arises is whether the unique natureof the aliphatic carbon-rich organics associated withcoarse-grained phyllosilicates observed in this study isa unique feature, only found in the Ryugu asteroid.
This question requires additional work. Further study
is needed to fully define the nature of the organics andtheir relationship with the surrounding hydrous
mineral phases.

Ⅲ- 5[1] Yada T. et al., Nature Astron (2021)
doi.org/10.1038/s41550-021-01550-6.
[2] Pilorget, C. et al., Nature Astron (2021)
doi.org/10.1038/s41550-021-01549-z.
[3] Uesugi M. et al., Rev. Sci. Instrum. 91 (2020) 035107.
[4] Ito M. et al., Nature Astron, in revision (2022).
[5] Tomioka N. et al., 53rd LPSC (2022).
[6] Yamaguchi A. et al., 53rd LPSC (2022).
[7] Greenwood R.C. et al., 53rd LPSC (2022).
[8] Cody, G.D. et al., Earth Planet. Sci. Lett. 272 (2006)
446.
[9] Keller, L.P. et al., Geochim. Cosmochim. Acta 68(2004) 2577.
[10] Sandford S.A. et al., Science 314 (2006) 1720.

149 1 Ⅲ05-

Ⅲ -5. Life,BL1U
Earth and Planetary Sciences

BL1U

Study of Pygmy Dipole Resonance using Linearly Polarized Photon BeamT. Shizuma1, M. Omer2, T. Hayakawa1, K. Ali3, H. Zen3, H. Ohgaki3, S. Miyamoto4,
K. Sugita5 and Y. Taira5

National Institutes for Quantum Science and Technology, Tokai 319-1106, Japan
2
Japan Atomic Energy Agency, Tokai 319-1195, Japan
3
Institute of Advanced Energy, Kyoto University, Uji 611-0011, Japan
4
Laboratory of Advanced Science and Technology for Industry, University of Hyogo, Kamigori 678-1205, Japan
5
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan1

the intensity asymmetry of resonantly scattered γ-rays
with respect to the polarization plane of the incident
photon beam.

Fig. 1. Photo of the experimental setup used for NRF
measurements at BL1U.
410Counts / 1 keV

Ⅲ- 5

The emergence of low energy dipole strength socalled Pygmy Dipole Resonance (PDR) has motivatedmany experimental and theoretical efforts [1]. The PDR
has been observed as a concentration of electromagnetic
strength near the low-energy tail of the Giant Dipole
Resonance (GDR). It provides useful information on
fundamental properties such as the neutron-skinthickness of medium to heavy nuclei, the nuclear
symmetry energy, and the properties of neutron stars.
The stable lead isotopes, including 206Pb, are suitable forthese studies since they exhibit an appreciable amountof low-energy dipole strength.
In a previous nuclear resonance fluorescence (NRF)
measurement for 206Pb using unpolarized bremsstrahlung[2], extra strengths were observed at the energy region
ranging from 5 to 8 MeV which could be related to the
PDR. The photo-absorption cross sections in 208Pb in
average amount to about 60% of that in 206Pb. Thisbehavior differs from that found in the series of xenon
isotopes, in which the summed dipole strength in theenergy region from 6 to 9 MeV increases with theneutron numbers [3]. Possible reasons are that thestrength in the quasi-continuum may not be neglected in
208
Pb either or that there are structural differences thatinterfere the effect of the neutron excess [3].
To study the PDR nature in 206Pb we measured NRF
γ rays using linearly polarized photon beam. The laser
Compton scattering (LCS) γ rays with a maximum
energy of 7.54 MeV were generated by collision of 746MeV electrons with linearly polarized laser photons
with a wavelength of 800 nm at a collision angle of 82
degrees. A lead collimator with a 18-cm thickness and
3-mm aperture was used to form a quasi-monochromatic
LCS photon beam. The photon flux was measured
during the NRF measurement by a large volume LaBr3
scintillation detector. The target consisted of a metallic
cylinder (8 mm in diameter) of enriched 206Pb. Fourhigh-purity germanium (HPGe) detectors were used tomeasure scattered photons from the target. Two of thesedetectors were placed in the horizontal plane at ascattering angle of 90 degrees and the others wereplaced in the vertical plane. The experimental setup is
shown in Fig. 1. A part of the photon scattering spectra
observed at a polar angle of 90 degree relative to thepolarization plane of the incident photon beam isrepresented in Fig. 2. The measured spectra are used todetermine the parities of the resonant states by extracting

2

10

0

10

0

4000
Energy (keV)

8000

Fig. 2. Typical γ-ray spectrum observed at a polar
angle of 90 degrees relative to the polarization planeof the incident photon beam.

[1] D. Savran et al., Prog. Part. Nucl. Phys. 70 (2013)
210.
[2] T. Shizuma et al., Phys. Rev. C 98 (2018) 064317.
[3] R. Massarczyk et al., Phys. Rev. Lett. 112 (2014)072501.

150 2 Ⅲ05-

BL3U

Ⅲ -5. Life, Earth and Planetary Sciences

BL3U

X-ray Absorption Spectra of Lipid Bilayer Membranes in Aqueous Solutions
R. Tero1, Yu Kinjo1 and M. Nagasaka2

Toyohashi University of Technology, Toyohashi 441-8580, Japan
2
Institute for Molecular Science, Okazaki 444-8585, Japan1

The lipid bilayer is a self-assembled structure ofamphiphilic lipid molecules and is the fundamental
structure of biomembranes such as cell membranes.
Internal structures of lipid bilayers, such as twodimensional domains and hydrophobic thickness, andphysical properties affect the transportation of materials,
information, and energy through the biomembranes. All
these physiological reactions proceed in the presence ofions. Ions in the aqueous solution significantly influence
to these structures and properties of lipid bilayers.
Phosphatidylcholine (PC) is the most abundant lipid ofeukaryotic cell membranes. Cations bind to thephosphate and carbonyl groups of PC. However, affinityof cations to PC and effects of cations to molecularorientation are still controversy especially in the fieldsof theoretical simulations [1]. We aim to determine thebinding affinity of cations to lipids in aqueous solutions
experimentally, by means of X-ray absorption
spectroscopy (XAS) [2,3].
Supported lipid bilayers (SLBs) of dioleoyl-PC(DOPC) were formed on the Si3N4 membranes of the
XAS flow cell [2] by the vesicle fusion method. We
prepared DOPC-SLBs with few residual vesicles asshown in Fig. 1. Fluorescence recovery after
photobleaching observation showed that fluid andcontinuous SLB covered the whole Si3N4 membranesurface. O-K edge XAS spectra of the Si3N4 membrane
before and after formation of SLB were obtained in abuffer solution (NaCl 100 mM, HEPES 25 mM/ pH 7.4
NaOH) which thickness was controlled to be less than
100 nm. The XAS spectrum of the Si3N4 membranewithout SLB was subtracted from that with SLB.
The O-K-edge spectrum of DOPC appeared at 531- 533 eV (Fig. 2). It is attributed to three components
due to the phosphate and carbonyl groups on the PC
headgroup: 1s→π* transitions of P=O, P-O-Na, and
C=O at 531.5 eV, 532.3 eV, 532.0 eV, respectively [3].
We measured XAS spectra at different incident angle toobtain the orientation of these groups in the lipid bilayer[4]. The relative intensity of the three components
varied with the incident angle (Fig. 2). The result
indicates that XAS in the aqueous sotion is capable toobtain information about the molecular orientation oflipids in bilayer membranes.
In conclusion, we obtained O-K edge XAS spectraof SLBs in an aqueous solution at various incident
angles. We will investigate the effects of the cation
concentration and species on the XAS components andtheir relative intensities.

Fig. 1. Fluorescence image of DOPC-SLB on the the
Si3N4 membranes of the XAS flow cell.

a

b

c

Ⅲ- 5

Fig. 2. O K-edge XAS spectra of DOPC-SLB obtained
at various incident angle: (a) 0°, (b) 35°, and (c) 48°.
Black dotted curves represent raw data. Dashed curves
and red solid curves show deconvoluted components
and their summation, respectively.
[1] T. B. Woolf, Biophys. J. 104 (2013) 746; A. Catte,
Phys. Chem. Chem. Phys. 18 (2016) 32560.
[2] M. Nagasaka, H. Yuzawa, T. Horigome, and N.
Kosugi, J. Electron Spectros. Relat. Phenomena 224(2018) 93.
[3] R. Tero, W.-Z. Goh and M. Nagasaka, UVSOR
Activity Report 2020 48 (2021) 129.
[4] H. Kondoh, F. Matsui, Y. Ehara, T. Yokoyama and
T. Ohta, Langmuir 17 (2001) 8178.

151 3 Ⅲ05-

Ⅲ -5. Life,BL4U
Earth and Planetary Sciences

BL4U

Evaluation of Exposure-Effects on Biomolecules for the Molecular Mappingof Biological Specimens Using STXM
A. Ito1, K. Shinohara2, A. Matsuura3, S. Toné4, M. Torigata1, K. Tohya5, H. Yuzawa6
and T. Ohigashi6,7

1School of Engineering, Tokai University, Hiratsuka 259-1292, Japan
Graduate School of Health Sciences, Fujita Health University, Toyoake 470-1192, Japan
3
Research Integrity Office, Fujita Health University, Toyoake 470-1192, Japan
4
School of Science and Engineering, Tokyo Denki University, Hatoyama 350-0394, Japan
5
Kansai University of Health Sciences, Kumatoricho 590-0482, Japan
6
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
7
School of Physical Sciences, The Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan2

though the repeated measurement and confirmation of
the results remained.
2.5

Absorption

(a)

2
1.5
1
0.5
0

(b)

283

285

287 289 291 293
Photon energy (eV)

295

397

399

401 403 405 407
Photon energy (eV)

409

530

532

534 536 538 540
Photon energy (eV)542

Absorption

1.5
1
0.5
0

(c)

1.5
Absorption

Ⅲ- 5

It is well recognized that spectromicroscopy using ascanning transmission X-ray microscope (STXM) inthe soft X-ray region is a powerful tool for themolecular mapping of biological specimens. We havebeen working on a quantitative mapping of nucleic
acids (DNA and RNA) and proteins (histone andbovine serum albumin abbreviated as BSA) in
chromosomes, cultured mammalian cells, and isolated
apoptotic nuclei using combined NEXAFS spectra at
the C, N and O-K absorption edges [1-3].
In the quantitative analysis, precise absorption
spectra of constituent molecules are definitely required.
However exposure of X-rays for the observation itself
could induce molecular changes resulting in the spectralchanges of them. Actually, we have calculated theexposure and absorption doses for biological specimens
in a hydrated condition to achieve a defined spatial
resolution based on the method by Sayre et al. [4], andestimated the number of DNA strand breaks generated[5]. For example to obtain 100 nm spatial resolution, theabsorption dose in the order of 104 Gy is required, which
induces about 105 DNA double strand breaks per cell.
In the present study, we evaluated the exposure-effects
on the spectra of major biological molecules such as
DNA, RNA, histone and BSA as a trial.
We prepared dry thin films of DNA, RNA, histone,
and BSA on SiN membrane. Each one micrometersquare area in the specimens was scanned with 10 x 10
pixels at the energy of C, N and O-K absorption edge
regions in this order with a dwell time of 6, 12 and 20
msec in addition to 2 msec for DNA. For each dwell
time the scanned area was shifted to the different area.
Figure 1 shows NEXAFS of DNA at the C, N and
O-K absorption edges with four kinds of dwell times.
A slight but significant change was observed in the
profiles of the spectra, though it was not clear whether
or not that was depending on the level of exposures.
In the case of RNA and histone, similar tendency
was observed. However for BSA, a clear change in the
profiles was observed in a dwell time dependent
manner.
At this stage of the results, we decided that spectra of
the molecules observed at the same exposure condition
should be chosen as the reference data for analysis,

1
0.5
0

Fig. 1. NEXAFS of DNA at the C-K (a), N-K (b), andO-K (c) edges. Dwell time: 2 (black), 6 (red), 12 (blue),and 20 (green) msec.

[1] K. Shinohara et al., Ultramicrosc. 194 (2018) 1.
[2] K. Shinohara et al., J. X-Ray Sci. Technol. 26 (2018)877.
[3] K. Shinohara et al., Cells 8 (2019) 8.
[4] D. Sayre et al., Ultramicrosc. 2 (1977) 337.
[5] K. Shinohara and A. Ito, J. Microsc. 161 (1991) 463.

152 4 Ⅲ05-

BL4U

Ⅲ -5. Life, Earth and Planetary Sciences

BL4U

Physicochemically Characterization of Dust/Salt Mixtures Originatingfrom the Source of East Asian Dust Storms
1

J. Li1, W. Liu1, L. Li2, T. Ohigashi3, M. Hallquist2, S. Wang1 and X. Kong2

Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, Northwest University,
Xi'an 710127, China
2
Department of Chemistry and Molecular Biology, University of Gothenburg, SE-412 96 Gothenburg, Sweden
3
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan

Mineral dust aerosols are a primary component in theatmosphere, accounting for almost half of troposphericaerosol masses, and they can deteriorate human living
conditions, endanger human health, and affectecosystems. In the context of global climate change, thetrend of warming and drying that is intensifying
desertification in northern China is clear. The dominantregional geophysical feature, the neighboring Third Pole,that is the elevated region represented by the Himalayas
and the Tibetan Plateau, impacts the entire planet’s
climate directly and via global teleconnections [1]. In
this study, dust, salts and mixed samples were collectedfrom important source regions of East Asian Dust
Storms, including the Badain Jaran Desert, the Tengger
Desert and the Ulan Buh Desert in northwestern China.
Scanning transmission X-ray microscopy (STXM)
measurements were performed at the BL4U UVSORIII beamline. For STXM measurements sample
particles were deposited on filmed TEM grids, anddata was analyzed with the aXis2000 program.
Example optical images are presented in Fig. 1, where
Fig. 1(a) is an image captured at 348 eV photon energy,
corresponding to calcium absorption. Potassiumcontaining particles in the same sample are highlighted
in Fig. 1(b) (297 eV) as the dark more cubic particles.
Individual particles were chemically mapped using
the STXM technique. Particle images are shown in Fig.
2 and a zoomed-in view in Fig. 2(a). Figure 2(a) shows
the two typically observed particle morphologies,
needle-like and more cubic or polygonal. We observedistinct chemical characteristics of the twomorphologies, as illustrated in Figs. 2(b)–2(d), which
include the carbon K-edge and potassium L-edge
spectra, the calcium L-edge spectra and the oxygen Kedge spectra.
The carbon K-edge includes the presence of acarbonate peak (at 290.2 eV) for needle particles that is
minimally present for the polygonal particles [2]. Given
the region around 284–290 eV is flat, these particles
cannot include significant black or organic carbon
components. At the potassium L-edge, a doublet at297.2 and 299.8 eV indicates the presence of potassiumin the polygonal particle [3]. In Fig. 2(c), the calcium Ledge shows the presence of calcium (at 348.8 and 352.1
eV) in the needle, suggesting the needle is likely CaCO3[2]. At the oxygen K-edge (Fig. 2(d)), one sharp peak isobserved at 533.6 eV in the needle, which likely
corresponds to the oxygen in the carbonate ions, whichfurther supports the supposition that the needle-likeparticles are dominated by CO3 and Ca. The broad

components in the oxygen K-edge spectra are associatedwith other oxygen species. These results show themixing state of the CaCO3 and K/O salts in sandsamples, and these two components most likely havedifferent solubilities, i.e., CaCO3 has low solubility inwater, but the K/O salts may be highly dissolvable. The
STXM results here provide unique information thatcannot be accessed by other conventional methods.

Fig. 1. STXM images shows the morphology ofdust/salt mixture particles. (a,b) Snapshots measured
at 348 eV and 297 eV.

Ⅲ- 5Fig. 2. STXM image and spectra of representative
particles. (a) Optical image, (b) spectra scanned at C
K-edge and K L-edge, (c) Ca L-edge spectra, (d) O Kedge spectra. Blue lines and red lines represent themean spectra for needle-like particles and polygonal
particles, respectively.
[1] Q. You et al., Earth-Sci. Rev. 217 (2021) 103625.
[2] K. Benzerara et al., Geobio. 2 (2004) 249.
[3] R. C. Moffet et al., Atmo. Chem. Phys. 13 (2013)
10445.

153 5 Ⅲ05-

Ⅲ -5. Life,BL5B
Earth and Planetary Sciences

BL5B

Development of Multilayer-coated Mirrors for the Next Generation of the
Inner Magnetospheric Imaging
K. Inoue1, A. Tomioka1, J. Yang 2, H. Lin2, K. Yoshioka1,2 and I. Yoshikawa1,2

Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo,
Tokyo 113-0033, Japan2
Department of Complexity Science and Engineering, Graduate School of Frontier Sciences, The University of Tokyo,
Chiba 277-8561, Japan1

Ⅲ- 5

Inner magnetospheric imaging at 30.4 nm, which is aresonantly scattered emission line by singly-ionizedhelium, contributed to our present understandings ofplasmasphere formation, emerges of fine structures andsolar wind interaction. RemFigote-sensing technique inthis spectral region has become known as a promising
tool in geophysics.
We have still strong motive in extension of the innermagnetospheric imaging since instrument developments
on Kaguya, Nozomi, International Space Station. A
multilayer coated mirror reflecting the EUV radiation at
the normal incidence has been providing solutions to
overcome the technical difficulties, i.e., existing optics
has less effective collection of EUV photons. Therefore,
multilayer coated mirrors have been employed for solar
physics and astrophysics as well. The multilayer coating
consisting of alternating layers of typically molybdenum
and silicon (Mo/Si) achieved the highest and stablereflectivity (approximately 20 %) at 30.4 nm, andtherefore it has been most often employed in the space
missions. The thickness of each layer should bedetermined by the trade-off as follows: it maximizes theconstructive interference of the incidence reflected ateach interface and it minimizes the total absorption to
enable more interfaces to contribute to the absolutereflectance increase.
Recently, we have shown the performance of the newmultilayer coated mirror, consisting of 40 pairs of Mg
and SiC. Its peak reflectivity achieved 30 % or higher.
However, we had to realize that the Mg/SiC multilayer
mirror has decisive disadvantage. The degradation of
the reflectivity occurred under the condition of hightemperature and/or high humidity. The interface between
two materials became unstable, the thickness of thelayer changes due to interfacial tension, and then thereflectance decreased dramatically (diffusion problem).
As a result, we were forced to use a conventional
multilayer mirror.
Space mission payloads have to survive hot and/or
humidity environments before the launch as well asvery cold condition in space. The development ofrobust instruments against environmental changes ismandatory for us.
More recently, we have designed a new multilayer
coating, (B4C/MgSi). We use the metal alloys of MgSi
instead of using bulk of Mg to solve diffusion problems.
Figure 1 shows the reflectivity of the coating for S- andP- polarizations. For both polarizations, the measured

reflectivities are relatively ~ 25 % lower than those of
the expectations by calculations (We have an ordinary
way using optical constants [1] to calculate thereflectivity). We will have some modification on the
manufacturing process (e.g., Mg/Si ratio) to increase up
to the expectations.
On the other hand, for non-polarization radiation (thatis our target in planetary science), we expect that we haveachieved higher reflectivity (average over S- and Ppolarizations, about 30 %) than that of a conventional
Mo/Si coating. The development will be progress nextyear.

Fig. 1. Reflectivity of the multilayer coating of
B4C/MgSi. We have measured the reflectivity for both
S and P polarizations. Predictions by the calculations arealso shown.

[1] Eric Gullikson. The Center for X-Ray Optics.
Retrieved March 27, 2022, fromhttps://henke.lbl.gov/optical_constants/

154 6 Ⅲ05-

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Ⅲ -5. Life, Earth and Planetary Sciences

BL5B

Performance Evaluation of an Optical Filter Aiming for Observation of
Atmosphere of Comets
Y. Sasaki1, Y. Suzuki2, K. Yoshioka1,2, M. Taguchi3, M. Kuwabara3, H. Akadama2, T. Kosugi1,
H. Lin1 and J. Yang1
1

Department of Complexity Science and Engineering, Graduate School of Frontier Sciences, The University of Tokyo,
Chiba 277-8561, Japan2
Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo,
Tokyo 113-0033, Japan3
Departmemt of Physics, Graduate School of Science, Rikkyo University, Tokyo 171-8501, Japan

Investigating the hydrogen isotope (D/H) ratio of
emitted gases from comets is important to understandthe water-related history of the solar system. Here, weare developing a Lyman-alpha line absorption cell thatcan distinguish the emission line of D and H, by utilizing
the resonance absorption of the hydrogen atoms. To
evaluate its performance, accurate calibration of the
wavelength for the monochromator is required. However,the BL5B facility is known to have a drift-like tendency.
Therefore, we examined the temporal shift of the
wavelength using the known absorption line of the
Krypton (Kr) .
We evaluated the wavelength shift by irradiating the
EUV light to the absorption cell filled with Kr gas (Fig.
1). The measurements were conducted three times. For
all measurements, the scanned wavelength was from122.6 nm to 124.6 nm, and the scan step was 0.01nm.
The slit width was 0.01 mm. The pin hole diameterwas 1 mm, and the grating and the mirror were set as“G3M5”. The gas pressure of the Kr gas was 1000 Pa.
The result is shown in Fig. 2. The absorption
wavelength by Kr is 123.58 nm in literature [1]. However,the figure shows two primary absorptions, 123.50 nm
and 123.80 nm. We have two hypotheses for this result.
The one is that the absorption near the wavelength of
123.50 nm might be the absorption by Kr, since its
wavelength is near that of Kr in literature [1]. Based on
this hypothesis, the other absorption, which is around123.80 nm, should be an effect of other substances. A
possible substance is water molecules. They absorb
light near the wavelength of 122.00nm, 123.85 nm, and124.10 nm. It is difficult to completely prevent watermolecules from entering the cell, so some watermolecules remaining in the cell might absorb the lightnear 123.80 nm. However, if this hypothesis is correct,
an absorption near 124.10 nm also should appear. As the
future work, we plan to dry the Kr cell completely bybaking enough and confirm whether the absorption
around 123.80 nm is derived from water molecules.
The other hypothesis is that both two absorption
lines are caused by water molecules. It means that the
wavelength adjustment by approximately +0.30 nm isneeded. Based on this hypothesis, we have to consider
the possibility that the absorption by Kr is too faint toobserve. The future work for this case is the same as
mentioned above, since if both absorptions are effectsof water molecules, both absorptions would disappear

by drying the cell. Moreover, we also should find out
appropriate Kr gas pressure.
As a supplementary experiment, we also evaluatedthe upper limit of absorption rate by hydrogen byfilling the cell with hydrogen gas. It can be derived by
calculating the ratio of the standard deviation to theaverage direct count, using the hydrogen-filled cell.
We call it “relative error”.
The measurement was conducted 10 sets. Eachmeasurement set has three trials. The scanned wavelength
was from 119.6 nm to 123.6 nm, and the scan step was
0.02 nm. The slit width was 0.01 mm. The pin holediameter was 1 mm, and the grating and the mirror wereset as “G3M5”. The hydrogen gas pressure was 200 Pa.
Electric energy applied to the filament in the cell waschanged from (1.05 W, 2002 K) to (2.60 W, 2740K).
As a result, the average “relative error” was 2.31 %.
This means that if the absorption for hydrogen Lymanalpha is less than 2.31%, we cannot find it out.
Therefore, we have to adjust the power for the filament
so that the absorption exceeds the ratio.

Ⅲ- 5Fig. 1. The setup of experimental instruments.

Fig. 2. The absorption spectrum of Kr. It shows
primary absorptions at 123.50 nm and 123.80 nm.
[1] National Institute of Standards and Technology,
NIST Atomic Spectra Database Lines Data, https://physics.nist.gov/PhysRefData/ASD/lines_form. html.
Accessed March 2, 2022.

155 7 Ⅲ05-

Ⅲ -5. Life,BL5B
Earth and Planetary Sciences

BL5B

Performance Evaluation of UV Absorption Filter Onboard SpacecraftY. Suzuki1, M. Kuwabara2, M. Taguchi2, K. Yoshioka1,3, T. Katsumata2, M.Tateyama2, K. Goda4,
A. Yamazaki4, K. Inoue4 and A. Tomioka4
1
Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo,
Tokyo 113-0033, Japan2
Department of Physics, College of Science, Rikkyo University, Tokyo 171-8501, Japan3
Department of Complexity Science and Engineering, Graduate School of Frontier Sciences, The University of Tokyo,
Chiba 277-8561, Japan
4
Department of Earth and Planetary Physics, Faculty of Science, The University of Tokyo, Tokyo 113-0033, JapanⅢ- 5

In the planetary science, deuterium-hydrogen (D/H)
isotope ratio of comets is emphasized to know theorigin of water on Earth. We develop an imager
onboard the Comet Interceptor spacecraft to observethis. However, small spectrometers have too low
wavelength resolution to distinguish emission lines of
H and D, whose wavelength are different only by 33
pm. To overcome this difficulty, we use gas filters
named Hydrogen Absorption Cell. This is a small glass
cell filled with hydrogen molecules, in whichfilaments are set. By applying voltage to this filament,
hydrogen molecules dissociate into atoms resulting inabsorption of Ly-α. It is noted that Ly-α of deuterium
is not absorbed. Therefore, we can evaluate D/H ratio
from the difference of the brightness of the observation
target when the voltage is applied (called “on”) and not
applied (called “off”) to the filament.
Our experiments aim to understand appropriatepressure of filled hydrogen for the future comet
exploration. We obtained transmittance spectra withseveral pressure conditions through the comparison of“on” and “off” data. Then, absorption width and depth
are evaluated using Gaussian fitting. Wavelength
scanning was performed using the G3M4 grating
system with the range of 121.5-122.5 nm, 0.02 nm steps
and summing 20 times. The higher hydrogen pressureis, the more difficultly the filament temperature rises,
since hydrogen molecules take away the heat of thefilament. Thus, experiments were conducted under
three conditions –temperature of the filament is fixed,
power applied to the filament is fixed, and applied
voltage is fixed.
The results are shown in Fig. 1. When power orvoltage are fixed, the temperature of the filamentdecreases and absorption gets shallower with higher
pressure. On the other hand, when filament’s temperature
is fixed to 1800 K, absorption gets deeper. However,power consumption also increases. Although it seems
that intermediate pressure (from 200 to 400 Pa) is thebest so far, we need to precisely discuss it in terms oflifetime of filaments and available power onboard thespacecraft.
When voltage is applied, filaments are expected toglow like light bulbs, which causes the contaminationof observation data. To verify this fact, we measured
the brightness with shutters closed. As we expected,
the filament gets brighter as its temperature rises.
Besides, at constant temperature, higher hydrogenpressure is found to suppress the brightness. Utilizing
this knowledge, we will soon estimate the expected
S/N ratio of the instrument mounted on the spacecraft.

Fig. 1. Dependence of absorption width and depth on the pressure of filled hydrogen in the cell.

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Ⅲ -5. Life, Earth and Planetary Sciences

BL7B

The Effect of Space Weathering on The PAH Wavelength of Interstellar
Dust Organic Matter
1

J. Yang1, H. Lin1, K. Inoue2, A. Tomioka2, K. Yoshioka1, 2 and I. Yoshikawa1, 2

Department of Complexity Science and Engineering, Graduate School of Frontier Sciences, The University of Tokyo,
Chiba 277-8561, Japan2
Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo,
Tokyo 113-0033, Japan

In astronomy, extinction is the absorption andscattering of electromagnetic radiation by dust and gas
between the emitting astronomical object and theobserver. Interstellar extinction was first recorded in1930 by Robert Julius Trumpler. However, its effects
were already noticed by Friedrich Georg Wilhelm vonStruwe in 1847, and its influence on stellar colors wasobserved by many, but they did not link it to theprevalence of galactic dust.
Polycyclic aromatic hydrocarbons (PAH) are aprevalent component of space organics and are present
in interstellar dust. They play an important role in avariety of astronomical observations in the ultraviolet
and far-infrared ranges, covering a wide range of objects
and environments from meteorites and interplanetary
dust particles to the outer solar system [1].
A prominent feature in the measured extinction
curves of many objects in the Milky Way is a broad"bulge" at about 2175 Å, right into the ultraviolet
region of the electromagnetic spectrum. This feature
was first observed in the 1960s, but its origin remains
unclear. Several models have been proposed to explain
the bulge, including graphite particles containing a
mixture of PAH molecules. Studies of embedded
interplanetary dust particles (IDPs) have observed thisfeature and identified the presence of carriers oforganic carbon and amorphous silicates in the particles.
The PAH present on Earth have an absorption bandwith a wavelength of about 210 nm. And due to theweathering of the universe, PAH may increase thewavelength range of the UV absorption band in theuniverse.
Therefore, it is assumed that the reflection band of
PAH on Earth has a wavelength of about 210 nm, which
may correspond to the absorption band of 217.5 nm thatappears in the interstellar darkening curve (the curve
describing the absorption spectrum of interstellar dust).
This experiment was conducted to observe andanalyze the effect of space weathering on the lightabsorption properties of PAH. We prepared PAH
samples Fig. 1) synthesized in the laboratory forcomparison experiments with PAH samples exposedon the International Space Station (ISS) (exposed
samples) and similar samples synthesized and stored
in the laboratory (unexposed samples), both exposed
and unexposed samples were made of PAH only andnot mixtures. We divided the reflectance properties ofthese samples into three parts with the non-exposed

samples in the wavelength range of 100-300 nm for theexperiments and compared the reflectance properties.
The reflectance properties of the Coronene samples
showed a significant decrease near 270 nm wavelengths
and a trend in the 210-280 nm wavelength range where
the attenuation of reflected light was more pronounced
in the longer wavelength range (Fig. 2).
This trend suggests that the wavelength
corresponding to the bottom of the depression may
shift to longer wavelengths due to space weathering.

PAH SamplessFig. 1. PAH samples installation diagram.

Fig. 2. The reflection characteristics of coronene
samples in the wavelength range of 160-300 nm.

[1] Salama, Farid. (2008). PAHs in astronomy - A review.
Proceedings of The International Astronomical Union.
251. 10.1017/S1743921308021960.

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Ⅲ -5. Life,BL7B
Earth and Planetary Sciences

BL7B

A study on Space weathering of Carbonaceous Meteorites by
Far-ultraviolet Spectroscopy
H. Akadama1, Y. Suzuki1, J. Yang2 and K. Yoshioka1,2

Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo,
Tokyo 113-0033, Japan2
Department of Complexity Science and Engineering, Graduate School of Frontier Sciences, The University of Tokyo,
Chiba 277-8561, Japan1

Ⅲ- 5

We study space weathering in Carbon-complex
asteroids by measuring the spectral shifts ofcarbonaceous meteorites due to weathering, focusing on
the far-ultraviolet (FUV; 50-200 nm). The feature of themeteorite materials on this spectral area has not beenmuch examined well.
Asteroids are believed to be well preserved inprimitive state since they have been left out of theplanetary formation process. Accordingly, they havebeen the focus of much attention as a clue to the natureof the early solar system. However, to analogize thepast state from the present observations, it is necessary
to understand the process of transformation such as
space weathering.
Space weathering is the dominant transformation
process on the surface of celestial bodies with thin
atmospheres, such as asteroids. This process is causedby solar photons, charged particles like energetic
electrons, and impacts by micrometeorites. The physicalproperties of such asteroid surfaces have been understood
mainly through spectroscopic observations in thevisible and infrared regions. However, the spectra inthese regions of Carbon-complex asteroids are
generally flat and have little characteristic shape [1]. On
the other hand, the UV spectra of organic compounds
vary remarkably with the degree of carbonization,suggesting that the UV region may be suitable for
evaluating space weathering effects on Carbon-complex
asteroids.
In this study, four types of carbonaceous chondrites
included in the meteorites were irradiated with FUV
light from the UVSOR BL7B, and the FUV spectra
before and after the irradiation were compared (Fig. 1).
To compare reflectance before and after UV irradiation,
relative reflectance with respect to a specific wavelength
was used.
As a result, bluing of the spectrum was observed in
the wavelength range of 50~200 nm (Fig. 2). This change
was the opposite of that observed for hydrocarbons
using polystyrene, and like that observed for bodies
with little or no organic matter, such as the lunar surface[2]. Since carbonaceous chondrites contain about 20
wt% of Fe, it is possible that a process of coating withFe of several hundred nm in size occurred by the UVirradiated surface, like that in the lunar surface.

Fig. 1. Light irradiation of a meteorite sample.

Fig. 2. Relative reflectance variation in a certain
carbonaceous meteorite (“Aguas Zarcas”). (Thehorizontal axis is wavelength [nm] and the verticalaxis is relative reflectance (normalized at red spots).
Blue and orange lines correspond to before and after
irradiation, respectively.)[1] S.J. Bus& R.P. Binzel, Icarus, 158 (2002) 146.
[2] A.Hendrix et al., Journal of Geophysical Research,
117 (2012) E12

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