Volume 38
Number 9
September 2023
Pages 1723–1896

JAAS

Journal of Analytical Atomic Spectrometry

rsc.li/jaas

ISSN 0267-9477

PAPER

Alexander Meshik et al.
Noble gas mass-spectrometry for extraterrestrial
micro-samples: analyses of asteroid matter returned by
Hayabusa2 JAXA mission

Open Access Article. Published on 21 July 2023. Downloaded on 10/15/2024 6:53:21 PM.
This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence.

JAAS
View Article Online

PAPER

Cite this: J. Anal. At. Spectrom., 2023,
38, 1785

View Journal | View Issue

Noble gas mass-spectrometry for extraterrestrial
micro-samples: analyses of asteroid matter
returned by Hayabusa2 JAXA mission†
Alexander Meshik, *a Olga Pravdivtseva,a Ryuji Okazaki,b Kasumi Yogata,cToru Yada,c Fumio Kitajima,b Hisayoshi Yurimoto,d Tomoki Nakamura,eTakaaki Noguchi,f Hikaru Yabuta,g Hiroshi Naraoka,b Kanako Sakamoto,cShogo Tachibana,ch Masahiro Nishimura,c Aiko Nakato,c Akiko Miyazaki, cMasanao Abe,c Tatsuaki Okada,c Tomohiro Usui,c Makoto Yoshikawa,cTakanao Sakai,c Satoshi Tanaka,c Fuyuto Terui,i Satoru Nakazawa,cSeiichiro Watanabe, j Yuichi Tsudac and Hayabusa2 Initial Analysis Volatile Team
Mass spectrometry of noble gas isotopes extracted from limited amounts of extraterrestrial materials
delivered by robotic space missions requires high sensitivity, high ion transmission, low detection limit,
and several other characteristics not readily available in commercial instruments. We compared two
diﬀerent conﬁgurations of electron impact ionisation. We concluded that the ion source with cylindrical

Received 19th April 2023
Accepted 23rd June 2023

symmetry and without a magnetic ﬁeld in the ionisation region is better for analyzing all stable noble gas

DOI: 10.1039/d3ja00125c

isotopes extracted from sub-milligram extraterrestrial samples. Isotopic analyses of noble gases retrieved
using multi-step heating of sub-mg samples delivered from near-Earth (162 173) asteroid Ryugu support

rsc.li/jaas

this conclusion.

Introduction
Noble gases and their stable isotopes are excellent geo- andcosmo-chemical tracers of geophysical processes1 because of
their very low concentrations in most natural materials.
However, their chemical inertness provides a relatively easymeans of separating them from major chemically active
components. Noble gases can uniquely identify “presolar”

aPhysics Department, Washington University, Saint Louis, MO, 63130, USA. E-mail:ameshik@physics.wustl.edu

bDepartment of Earth and Planetary Sciences, Kyushu University, Fukuoka, 819-0395,
Japan

c

Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency(JAXA), Sagamihara, 252-5210, Japand

Department of Earth and Planetary Sciences, Hokkaido University, Sapporo, 0600810, Japane

Department of Earth Science, Tohoku University, Sendai, 980-8578, Japanf

Division of Earth and Planetary Sciences, Kyoto University, Kyoto, 606-8502, Japang
Department of Earth and Planetary Systems Science, Hiroshima University, HigashiHiroshima, 739-8526, Japanh

UTokyo Organization for Planetary and Space Science, The University of Tokyo, Tokyo,
113-0033, Japani

Kanagawa Institute of Technology, Atsugi 243-0292, Japanj

Department of Earth and Environmental Sciences, Nagoya University, Nagoya, 4648601, Japan† Electronic supplementary information
https://doi.org/10.1039/d3ja00125c(ESI)

available.

This journal is © The Royal Society of Chemistry 2023

See

DOI:

(predate solar system) components that are barely resolvable byisotopes of other elements.
The Sun contains more than 99% of the total solar system
mass, including the most extensive inventory of noble gases,
which are omnipresent in the surface layer of all materials
exposed to the Solar Wind (SW). The second most abundant
noble gas component is Q (for quintessence, ref. 2), carried by
the carbonaceous mineral assembly (phase-Q) in the acidresistant residue le aer HF- and HCl-dissolution of the
99.5% of the meteorite mass. The isotopic composition of heavy
noble gases in phase Q resembles mass-dependently fractionated solar wind suggesting “local” (ref. 3) rather than “presolar”(ref. 4) origin. The isotopic structure of presolar noble gases
diﬀers from both solar and Q. These presolar isotopes wereformed in various nucleosynthetic processes in stars andinherited by material accreted from the protoplanetary disc. XeHL with a U-shaped isotopic pattern due to paired excesses inboth heavy and light isotopes is likely produced by the r-process(rapid neutron capture) and the p-process that generates
proton-rich isotopes. Lighter noble gases (Kr, Ar, Ne, and He)
co-released with Xe-HL are also labelled – HL since they seemingly have a common carbonaceous carrier in primitive meteorites – nanodiamonds. Noble gas isotopes from “presolar”
silicon-carbide and graphite preserve the record of slowneutron capture (s-process) that occurred in asymptotic giant
branch (AGB) stars.5 All above mentioned noble gases (oencalled “trapped”) carry specic isotopic signatures

J. Anal. At. Spectrom., 2023, 38, 1785–1797 | 1785

View Article Online

Open Access Article. Published on 21 July 2023. Downloaded on 10/15/2024 6:53:21 PM.
This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence.

JAAS
characteristic of their mineral hosts (reference compositions in
ESI†). Other isotopes formed in situ have accumulated laterfrom radioactive decay, spallation, and other nuclear reactions.6
Refractory minerals retain signatures of the early processes;
other materials may lose nucleosynthetic noble gases to various
degrees due to thermal and/or aqueous alteration. Isotopic
analyses of noble gases extracted from diﬀerent solar systemobjects reveal ngerprints of various processes that have led totheir present isotopic composition and ultimately decipher theformation and evolution of the analysed materials.
Extraterrestrial materials available for (destructive) noble gas
analyses are oen limited or insuﬃcient for retrieving useful
information. This was the rationale for developing analyticaltechniques capable of reliable mass-spectrometric analyses of
all noble gas isotopes from sub-mg asteroid material.
Washington University Noble Gas Laboratory (WUNGL)7 has
four operational mass spectrometers: multi-collector Noblesse(NU-Instruments), Helix-MC+ (ThermoFisher), and two nearly
identical single collector instruments, one built in Zurich,8
another cloned later in St. Louis. All instruments have magnetic
sector geometry, electron impact ionization, and identicalcalibration systems. Three mass spectrometers can share gas
extraction lines, which provides a direct comparison of theirperformances by analysing gas released from the same sample.
This arrangement allowed us to optimize the experimental
conguration for obtaining the most accurate and precise
isotopic composition of all noble gases extracted from themicrogram samples of the asteroid Ryugu delivered by the
Hayabusa2, JAXA mission.

Methods
Sensitivity
Sensitivity is crucial for analysing small amounts of noble gases
when ion counting statistics limit precision. In 1950–1960 noble
gas mass-spectrometry experienced three signicant advancements: (1) static vacuum mode of operation, (2) bright Nier ion
source utilizing electron impact ionization, and (3) an ioncounting detection. These three innovations dramaticallyincreased sensitivity, reducing detection limits; thus, making
noble gas isotope mass spectrometry an invaluable tool forisotope geochemistry, geochronology, and nuclear physics.
Since then, however, the sensitivity of noble gas mass spectrometers has remained the same. Three commercial noble gas
instruments dominate the present market – Noblesse (NuInstruments), Helix (ThermoFisher Scientic), and NGX (IsotopX). All three have the same fundamental ∼1 mA Torr−1
sensitivity as the earlier generation instruments VG-5400 and
MAP-215 (when renormalized to the same electron emission
current).
Since ionization cross sections and ionization potentials of
the elements cannot be changed, the only way to improve thesensitivity of the ion source is to increase electron density in theionization region by increasing the electron emission current.
Increased current can be achieved by reducing work function by
doping tungsten lament with some REE, or using a lanthanum
hexaboride (or similar) emitter. It is feasible to further increase

1786 | J. Anal. At. Spectrom., 2023, 38, 1785–1797

Paper
the path of electrons by optimizing the magnetic eld conguration in the ion source, but no signicant progress has beenreported yet. Resonance ionization dramatically improves ofsensitivity for the major Xe and Kr isotopes,9,10 but light, lowabundant isotopes are oen aﬀected by unresolvable, nonresonantly ionized hydrocarbons.9 Hence, this elegant technique does not work for Ar, Ne, and He. Recently developed,
a quadrupole ion trap mass spectrometer achieves the sensitivityof 1 × 1013 cps Torr−1 (ref. 11), three orders of magnitude lessthan the sensitivity of modern magnetic sector instruments.
Another approach is the implementation of the highsensitivity Baur–Signer ion source with cylindrical symmetry.12
The ring-shaped lament emits a hollow cone of electrons anddoes not require an electron-focusing magnet essential for
operating the Nier ion source. The magnetic eld in the ionforming region bends ions of diﬀerent mass/charge, introducing elemental and isotopic discrimination. The magnet-free
Baur source has much smaller and more stable mass discrimination allowing to analyse all noble gases without re-tuning theion source. It is also ∼4 times more sensitive than the Niersource,12 but its sensitivity is pressure dependent. Compared to
the Nier source, ions in the Baur source stay in the ionization
area longer (nearly zero extraction potential), which causes
undesirable space charge eﬀects making sensitivity pressure
dependent and limiting the application of the Baur source forthe analyses of terrestrial samples. Later source modications(GS 73, GS 75, and GS 98) address nonlinearity but at theexpense of ion transmission and sensitivity.12 However, for thepuried gas extracted from sub-milligram natural samples, thestatic pressure in the mass spectrometer remains well below
10−9 Torr, and the ion count rate rarely exceeds 105 count per s(except for 40Ar).

Ion transmission and consumption
Ion transmission — the fraction of ionized atoms passed
through the instrument and counted by the detector — isanother crucial factor in analyses of small gas amounts. Hightransmission is needed to minimize an instrumental bias, mass
discrimination, that “must vanish as the transmission
approaches 100%”.13 Nier-type ion sources typically have lessthan 20% ion transmission. Even in “bright” sources, only oneof every ve ions is detected. In contrast, the Baur ion source,
especially its early version, has at least 90% transmission.12
Other factors to consider for micro-analyses of noble gases
include gas consumption during the measurements andmemory eﬀects. In static vacuum mode, a mass-spectrometer
acts like an ion pump. During the measurements, the countrates steadily decrease due to ion implantation into the detector
and beam-dening electrodes. Newly ionized atoms of noble
and chemically active gases can knock out previously implanted
ions, increasing the count rate with time. When the contributions of these two counteracting processes are compatible, thetime evolution of the count rate becomes non-monotonic. As
a result, the count rate needs to be approximated by two
superimposed exponents to interpolate the count rate to thebeginning of the analysis (Fig. 1).

This journal is © The Royal Society of Chemistry 2023

View Article Online

Open Access Article. Published on 21 July 2023. Downloaded on 10/15/2024 6:53:21 PM.
This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence.

Paper

JAAS
units; i.e., the same isotope is measured by diﬀerent ion
detectors in the same run.15,16 It allows directly estimating of theeﬃciency ratios but only between neighbouring detectors. The
ratios of isotopes further apart are the product of several
correction factors, which inates analytical errors. Thisapproach is not useful for the analyses of small ion signals.

Ion counting

Fig. 1 Time-evolution of similar Xe signals with noticeable memory
eﬀect (top panel, copy of Fig. 3a from ref. 14). A strong memory eﬀectcauses the increase in count rate during the ﬁrst three cycles. The
linearly zero-extrapolated value of 41 ± 1 Hz is meaningless. The actual
initial count rate is likely <36 Hz observed in the ﬁrst cycle. Hence, this
instrument appears have been exposed to signiﬁcant quantities of Xe.14
A Similar signal of 130Xe without a noticeable memory eﬀect is shownat the bottom panel. A linear zero-extrapolated value of 53.3 ± 0.7 Hz
is most likely correct. Vertical error bars correspond to standard
deviations of count rates in one measurement cycle. Total number ofcycles is 25. Two data points were rejected since their corresponding130
Xe/132Xe ratios deviate from the ﬁt line by more than 2.5s.

In practice, noble gas analyses only last once all ions getcounted. Although longer duration analyses would improvecounting statistics, the systematic errors would increase due tothe memory eﬀects. The counting rate “half-life” determines
reasonable analysis duration. In our instruments with a Baurion source, this time is about 1 hour, while for our Helix-MC+
and Noblesse, the half-life is between 15 and 20 minutes, whichsignicantly compromises counting statistics.
Multicollection
The early generation of noble gas mass spectrometers operated
in single collection mode: only one isotope was measured ata time, while others were not counted. In this respect, theintroduction of simultaneous counting of several isotopes
provided a signicant improvement due to better utilization ofions. There is a drawback, however. In static vacuum mode, theion beam intensity is proportional to the partial pressure of theanalysed isotope and hence inversely proportional to theinternal volume of the mass-spectrometer. Therefore multicollection comes at a price – the gain in ion collection eﬃciency is compromised by increased volume, making these
instruments not signicantly better than the traditional singlecollector mass spectrometers. For example, the 5-multiplier
Noblesse mass-spectrometer has about a 3 litre volume, morethan three times larger than our single collector instruments.
Additionally, in multi-collector instruments, a new source ofsystematic error appears – variations of relative counting eﬃciencies of the electron multipliers. This problem is typicallymitigated by shiing the magnetic eld by one or two massThis journal is © The Royal Society of Chemistry 2023

Despite recent advancements in sub-femtoampere current
measurement techniques,17,18 ion counting with secondary
electron multipliers remains the only practical option for small
ion currents. As the count rates become lower, the pulse height
distribution of the electron multiplier becomes a crucial
parameter for separating a valid ion signal from the multipliernoise. The optimal pulse discrimination level depends on themass of incoming ions19 and should be adjusted as the multiplier ages. In an attempt to make the instrument “userfriendly”, manufacturers of commercial noble gas massspectrometers do not necessarily provide a means to investigate pulse height distribution, e.g., the ability to select andadjust the discrimination threshold depending on analysed gas.
Meanwhile, for low count rate measurements, setting a correct
discrimination level for analyses of diﬀerent noble gases andmonitoring pulse height distribution is essential to maximize
counting eﬃciencies, reject noise, and double counting causedby pulse ringing.
In our built-in-house instruments, the operation andisotopic analyses are controlled by a exible LabView code thatallows setting an individual discrimination level for each gas
and, if necessary, for each isotope. One of the routines
embedded in this code is a determination of pulse height
distribution (Fig. 2) that diagnoses the multiplier health andhelps to determine an optimal discrimination level for eachmass.
During isotopic analyses, two identical channels simultaneously count each ion beam with slightly diﬀerent (by a few

Screenshot of pulse height distribution (bin size is 1 mV) for low
Xe count rate suggesting an optimal discrimination level of about –40 mV; for the most abundant 132Xe it is about –60 mV. Commercial
noble gas instruments cannot obtain this representation of pulse
height distribution for small signals. Instead, the count rate as a function of the multiplier voltage is used. Such a plot, however, does notallow ﬁnding the optimal discrimination threshold and does not work
for low count rates.
Fig. 2
124

J. Anal. At. Spectrom., 2023, 38, 1785–1797 | 1787

View Article Online

Open Access Article. Published on 21 July 2023. Downloaded on 10/15/2024 6:53:21 PM.
This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence.

JAAS

Fig. 3 Time-evolution of small signal corresponding to ∼5000 atomsof 124Xe. Even in this extreme case no memory ingrowth is observed.
Zero-extrapolated value is 0.33 ± 0.06 counts per s. Two data points
are rejected since the corresponding 124Xe/132Xe ratios deviate fromthe ﬁt line more than 2.5s.

mV) pulse discrimination thresholds. Although this approach
does not improve the counting statistics (the same number of
events), it monitors pulse height distribution change during
analysis. To enhance sensitivity, we compared two discriminator settings based on the cumulative count rate of all
isotopes. If these sums are within statistical errors, then the
count rates for both channels are averaged. If one is signicantly larger than the other, only one set of count rates is taken
into account. This ion detection method makes low count ratemeasurements more reliable and provides early warning of
possible multiplier problems – e.g., degrading, aging, or darkcurrent changes. Fig. 3 illustrates the result of our eﬀorts toanalyse minute amounts of noble gases extracted froma microgram-size sample.
Background
Minimizing experimental background is an obvious requirement for the analyses of small samples. Extraterrestrial materials from meteorites and asteroids have fresh, well degasses
surfaces susceptible to the terrestrial contaminants.20 This
assertion especially applies to small particles with a highsurface/volume ratio. Samples from asteroid Ryugu analysed inthis work are the rst extraterrestrial material that largely
avoided terrestrial contamination due to careful planning andexecution of the JAXA Hayabusa2 mission.21–23 However, mass
spectra always contain background signals from the intrinsic
atmospheric noble gases and hydro- and uro-carbon residual
contaminants that can interfere with noble gas isotopes.
Isobaric interferences
Oils and lubricants are the primary sources of hydrocarbons in the
background. Commercial mass-spectrometers typically use
economical, claimed to be oil-free, turbomolecular pumps or
popular tabletop pumping stations that contain an ∼8 ml oil
cartridge on the low vacuum side. In case of power/vacuum
failure, the entire vacuum system could be easily contaminatedby the oil vapours from this cartridge. We mitigate this risk using
true oil-free Osaka turbopumps with magnetically levitated rotors
backed by a scroll pump. The Osaka pump obtains a pressure of<5 × 10−10 mbar. Further pressure reduction is achieved with two
1788 | J. Anal. At. Spectrom., 2023, 38, 1785–1797

Paper
40 l s−1 ion pumps. All components of our vacuum systems weremachined using water-soluble lubricants and acetone as cutting
uids. Whenever possible, the internal surfaces of the gas preparation line were electro-polished, and ultra-sonicated in acetone
and de-ionized water. All vacuum lines are at least 34” OD tofacilitate electro-polishing and to maximize pumping speed. The
entire system has been repeatedly baked to 275 °C and isconstantly kept at 90 °C. Further background improvement has
been achieved by utilizing a hot (>1000 °C) W-lament that cracks
long hydrocarbons into smaller fragments that miniature Tisublimation pumps can adsorb. However, ubiquitous hydrocarbons are still present at low levels and interfere with some noble
gas isotopes. Most of these interferences are only partiallyresolvable from Xe, with the most prominent being C3F5 (m/z =131) C9H20 (m/z = 128) and C6H6 (m/z = 78).
Other types of barely resolvable isobaric interferences areprotonated peaks: HD+ and H3+ from 3He and 20NeH+ from
21
Ne+; and double charged CO2++ from 22Ne+, 40Ar++ from 20Ne+.
We use predetermined correction factors to account for all theseinterferences and measure peaks with m/z = 2, 3, 4, 18, 19, 20,
21, 22, 40, 44 in the same run. This approach is possible due toan excellent Varian Mat magnet with rapid and reproducible
eld stabilisation, in just a couple seconds, with little eldscanning required to remove the hysteresis. Finally, there is theinterference of 80Kr+ with 40Ar beam due to the so-called“change of charge” eﬀect. Nevertheless, all Kr and Xe isotopes
can be measured in the same run if Ar is not abundant or/and
cryogenically separated.
The background of a clean well-baked vacuum system typically has a near atmospheric isotopic composition and usuallyconstitutes a negligible fraction of the extracted gas. However,the background contribution (blank) can be signicant andisotopically distinct when analysing a limited amount of gas.
There are some peculiarities of noble gas background (blanks)that we do not entirely understand. For example, blanks madebefore sample fusion are sometimes larger than aer the
sample has been melted and presumably completely degassed.
Melting a few mg of Al- or Pt-foil has the same eﬀect on thenoble gas blank. It could be that hydrogen from these foils
reduces some remaining, not completely degassed surface
impurities. If excessive hydrogen becomes a problem during theanalysis, a Pd-lter can remove it. This approach was utilized
during analyses of solar wind collectors from Genesis NASAmission.24 Kept at ∼450 °C, it eﬀectively removed hydrogenfrom the vacuum system. In this work, however, we did not use
this technique since it increases CO2++, which interferes with
22
Ne+ in the mass spectrum.

Noble gas extraction
The two most common gas extraction techniques are heating inultra-high vacuum using high-temperature vacuum ovens orlasers. Several laser extraction systems operating at 1064 (CWand Q-switched modes), 533, 266, 193 nm, and vacuum
furnaces with capacities ranging from 25 g to 10 mg wereavailable for this work. However, we found that these options
are not optimal for degassing sub-mg samples. Furnaces

This journal is © The Royal Society of Chemistry 2023

View Article Online

Open Access Article. Published on 21 July 2023. Downloaded on 10/15/2024 6:53:21 PM.
This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence.

Paper

JAAS

typically have a high noble gas background, and laser extraction
has poor temperature control, especially below ∼800 °C.
Preparing mineral fractions from micro samples in an airlessenvironment is not feasible. Therefore to separate gases
released from various minerals, we employed step-wise gas
extraction, taking advantage of the diﬀerence in thermal properties of the minerals involved. A miniaturized gas-extraction
low-blank oven was built and calibrated up to 2000 °C for thiswork. This device was specically developed to facilitate loading
Ryugu samples without exposing them to the terrestrial atmosphere. An earlier version of this oven was used for analyses ofnoble gases from the 0.44 mg sample of IOM from the Paris
meteorite.25 The current version used in this work has an
improved multilayer tantalum thermal shielding to homogenize temperature along the W-coil and all-metal sample loading
device with custom made 6 mm thick sapphire viewport toobserve manipulation of Pt-capsules containing micro-samples.
This device was specically developed to facilitate loading
Ryugu samples without exposing them to the terrestrial atmosphere. The sample loading procedures along with sample
weighting were performed in dry nitrogen, following the intricate protocol developed by Kyushu University (ref. 26 and 27).
Testing the experimental setup
To estimate the overall performance of our analytical setup, it
would be reasonable to analyse noble gases extracted froma well-characterized, inter-laboratory standard that is homogeneous at sub-mg level. Unfortunately, except for Ar, no suchstandard exists to our knowledge. Instead, small calibrated
shots of air are typically used as laboratory standards. However,a standard protocol has yet to be established for preparing,
purifying, and admitting these air shots to the mass spectrometer. Pneumatically controlled valves commonly employed
to “pipette” air standards into mass-spectrometers act too fast
to completely avoid fractionation caused by molecular ow
regime, with the extent of this fractionation depending on theinternal volumes and conductance of a particular vacuum line.
Besides the extensive noble gas analyses of solid material
returned from Ryugu,26,27 JAXA collected the head gas accumulated in sample return capsules. Several well-equilibrated
aliquots of this gas were prepared28 and distributed among
diﬀerent laboratories, where they were independently analysedusing diﬀerent mass spectrometers and gas preparation techniques.29 We will not discuss the results of these works here but
rather consider the head gas sub-samples as a perfectly
homogenized noble gas standard. Fig. 4 shows several noble gas
isotopic ratios that include the least abundant isotopes. While
the plotted ratios generally agree, 1s error bars corresponding
to ratios are diﬀerent for the diﬀerent experimental setups.
Isotopic ratios obtained using Nier-type ion sources (Fig. 4a andd) are generally less precise compared to those from Baursources (Fig. 4b and c).
Stability of the instruments with timeHigh ion transmission and the absence of a magnetic eld in
the ionisation region make sensitivity stable and less mass-This journal is © The Royal Society of Chemistry 2023

Selected isotope ratios in the head gas from the Hayabusa2
sample return container, as measured by diﬀerent laboratories
employing diﬀerent mass-spectrometry and noble gas extraction andpuriﬁcation techniques. Plotted data (from Table S1 in ESI,† ref. 29)
were obtained using Nier-type ion source: at GRPG, Nancy (a); Kyushu
Univ., Fukuoka (d) and Baur source: with reduced space charge eﬀects
at ETH, Zurich (b) and high transmission version at Washington Univ.,
St. Louis (c). Shown errors are 1s.

Fig. 4dependent compared to the commercial mass-spectrometers
equipped with the Nier-type ion source with an electron
focusing magnet. The ring-shaped lament of the Baur ion
source has a uniform temperature and provides nearly the same
ionisation probability for each emitted electron. It is regulated
by electron emission current, in contrast to electron trap
current in the Nier-type source, which is typically a fraction of
the emission current. This diﬀerence is likely the main reason
for the long-time stability and reliability of the Baur source. The
stability sensitivity and small and constant instrumental mass
discrimination do not require frequent instrument calibration
with air standards, saving time and reducing atmosphericmemory. The ring lament operates at a relatively low temperature and lasts years, with little or no source retuning being
needed aer its replacement.
Our single collector instruments employ a stable, longlasting Allen-type electron multiplier with Cu–BeO-dynodes.
This alloy is known to provide a higher and more stable yieldof secondary electrons than Al2O3, which is oen preferred byelectron multiplier manufacturers because of the concerns ofberyllium toxicity.

J. Anal. At. Spectrom., 2023, 38, 1785–1797 | 1789

View Article Online

Open Access Article. Published on 21 July 2023. Downloaded on 10/15/2024 6:53:21 PM.
This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence.

JAAS

Paper

Electronic units of our high ion transmission instruments
are from reliable manufacturers: Spellman (Hauppauge, NY,
USA), Stanford Research Systems (Sunnyvale, CA, USA), Bruker(Ettlingen, Germany), and Kepco Inc. (Flushing, NY, USA), withall of the units being controlled via GPIB using LabView(National Instrument, Austin, TX, USA) codes.

Results
Based on the on-hand comparison of several instruments anddevelopmental work described above we have selected the best
presently available for us technique for isotopic analyses oflimited quantities of noble gases. It is the built in-house highsensitivity (5 mA Torr−1 at 0.25 mA electron emission) 21 cm
radius 90° magnetic sectors mass-spectrometer. This instrument is equipped with >90% ion transmission ion source
without an e-focusing magnet and operates at the 3 kV acceleration voltage for Kr, Xe, and Ar and at 4 kV for light noble
gases. This conguration results in low memory and long (>1 h.
for Xe and Kr) useful ion-counting time (as Fig. 1 and 3 show).
Instrumental mass discrimination is small (0.06%/u for Xe) andstable (e.g., ref. 30). Sensitivity is stable, varies only few percent
over a long time (see Fig. S2 in ESI†), and the instrument
practically does not require retuning.
A miniature gas extraction low-blank oven was calibrated to±15 °C. Chemically active gases were removed using a series of
SEAS getters and freshly deposited Ti-lms. A hot tungsten
lament facilitated the cracking of complex hydrocarbons intofragments that more readily react with the getter material.
Noble gases were separated cryogenically before the isotopic
analyses into the fractions He + Ne, Ar, and Xe + Kr. Xe blank(1770 °C × 10 min) of ∼3 × 10−15 cm3 STP was determined bymelting of Pt foil of the same weight as the Pt capsules containing actual samples.
We applied our developments for analyses of all noble gas
isotopes from two Ryugu samples: A0105-04 (173 mg) and C010605 (82 mg), collected from the rst and the second touchdown
sites, respectively.31 Ref. 26 and 32 report the preparation of the
Ryugu samples and initial analyses. Gases were extracted in 7
temperature steps from C0106-05 and in 11 steps from A010504. Each extraction step lasted 10 minutes aer the temperature reached the set point. Xe and Kr from A0105-04 suggest
three major gas release peaks, while lower resolution stepheating of C0106-05 resolved only two peaks (Fig. 5).

Release proﬁles of the most abundant isotopes of noble gases
released during step-wise heating from Ryugu samples collected fromtwo diﬀerent locations on the asteroid. Ordinates show temperature
steps normalized to °C; therefore areas under the release curves
accurately represent gas amounts.

Fig. 5

ratio with temperature results from a depth-dependent
implantation eﬀect, similar to the fractionation observed in
Genesis solar wind collectors (Fig. 5a in ref. 15).
Main Ne release occurs between 500 °C and 1260 °C. Neon
released in this temperature interval is a mixture of solar wind,Q, and cosmogenic Ne, except for the 1260 °C extraction of theA0105-04 sample (Fig. 7).
Temperature fractions below ∼900 °C are dominated bysolar wind with a minor addition of cosmogenic Ne, which issomewhat smaller for C0106-05. Ne–Q dominates Ne at higher
temperatures, with 1000–1300 °C being a typical destruction
temperature of phase Q. At low and high temperatures,amounts of Ne released from both Ryugu samples only
marginally exceed the blank level. The isotopic composition of

Helium and neon
He (m/z = 3, 4) and Ne (m/z = 20, 21, 22) were not cryogenicallyseparated from each other and analysed in one run along withpeaks at m/z = 2, 18, 19, 40, 44 required for isobaric corrections
that were applied individually within each mass scans. Blank
corrections were applied using analyses of noble gases extracted
from empty Pt-capsules identical to those containing actual
samples. Isotopic compositions of He (Fig. 6) are consistent
with pure and/or fractionated solar wind with possible minor
contributions of He from phase Q at high temperatures.
However, it is more likely that the apparent decrease in 3He/4He

1790 | J. Anal. At. Spectrom., 2023, 38, 1785–1797

Fig. 6 Isotopic composition of helium released from Ryugu samples
A0105-04 (red diamonds) and C0106-05 (blue circles). Dotted lines
correspond to solar wind (SW), fractionated solar wind (FSW) and He
associated with phase Q (P1).16

This journal is © The Royal Society of Chemistry 2023

View Article Online

Open Access Article. Published on 21 July 2023. Downloaded on 10/15/2024 6:53:21 PM.
This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence.

Paper

JAAS

Fig. 8 Argon isotopes released from Ryugu samples A0105-04 (reddiamonds) and C0106-05 (blue circles). End-member components(SW, A, Q, HL, and cosmogenic) are the same as in Fig. 7. Error bars are
1s.

Neon isotopes released from Ryugu samples A0105-04 (reddiamonds) and C0106-05 (blue circles). Numbers indicate Ne
extraction temperatures (in °C). Filled symbols and bold numbers
correspond to the major gas release. Compositions of neon endmember components (S – Solar wind, Q – phase Q, A – atmospheric,H – neon-HL associated with meteoritic nanodiamonds, G – nearlypure 22Ne produced in s-process and carried by SiC, and cosmogenicNe) are from ref. 33–35. Dashed lines illustrate the trend of Ne isotopic
composition during step-wise heating. As extraction temperature
increases, Ne composition departs from the solar wind – cosmogenic
mixing line towards Ne-HL. This trend is evident for A0105-04 (red)and suggestive for C0106-05 (blue). Errors are 1s.
Fig. 7and 0.1840 ± 0.0009 (1s) for A0105-04 (Fig. 9). The diﬀerence
between these two values is statistically insignicant.
However, there is small but statistically signicant diﬀerencein the y-intercepts of the tting lines: (2.26 ± 0.84) × 10−5 forC0106-05 and (0.90 ± 0.55) × 10−5 for A0105-04. Both samples
apparently have 38Ar resolvable from zero at 1s level, with
C0106-05 having more cosmogenic 38Ar contribution thanA0105-04.
Krypton and xenon

Ne in A0105-04 suggests the presence of Ne-HL, which is associated with meteoritic nanodiamonds. This component is notapparent in C0106-05, possibly due to the heterogeneous
distribution of the Ne-HL component among ∼100 mg grains.
Neon released at 340 °C and 1610 °C from both samples
tentatively show contribution from Ne–G associated withgraphite and/or SiC; however, the large error bars (Fig. 7, further
inated aer blank subtraction) prevent from this conclusion.

Argon
Aer He and Ne analyses, argon was further cryogenicallyseparated from Kr and Xe and admitted to the mass spectrometer for analyses. In addition to Ar isotopes (m/z = 36, 38,40), m/z = 35, 37 were also analyzed to correct for the ubiquitous
H35,37Cl+. The interference corrections were applied for each of
the twenty-ve measurement cycles individually.
Argon is released from both Ryugu samples in one broad
peak from ∼400 °C to 1500 °C (Fig. 5). Within experimental
uncertainties, 36Ar/38Ar ratios are uniform and close to solar
wind Ar35 at these temperatures, while outside this range, they
are similar to Q and/or atmospheric values. There is neither
indication of Ar-HL nor of cosmogenic argon. The latter is likely
due to the low abundance of target elements in phase Q. If both
Ryugu samples were similarly exposed to the solar wind, theA0105-04 apparently retains its signature better as suggested bytemperature fractions below ∼700 °C (Fig. 8).
Both samples contain highly variable amounts of 40Ar. Welldened correlations of 38Ar/40Ar with 36Ar/40Ar yield thefollowing values of 38Ar/36Ar: 0.1833 ± 0.0054 (1s) for C0106-05
This journal is © The Royal Society of Chemistry 2023

It is diﬃcult to estimate the contributions of solar and other Kr
components, even for the most abundant isotopes, because of
the relatively small isotopic diﬀerences in major Kr components. Krypton isotopic compositions that correspond to hightemperature fractions scatter within 1–2s around atmosphericand Q values, while at temperatures below ∼700 °C they arecloser to the solar wind value (Fig. 10).
86
Kr/84Kr ratios in mid-temperature fractions (1000–1500 °C)
are marginally elevated compared to Q-value, suggesting
possible contributions from Kr-HL and/or Kr-G.
The three heaviest Xe isotopes (m = 136, 134, 132) are typically the most abundant and thus measured more precisely
than other isotopes. However, the 3-isotope plot corresponding

Fig. 9 Slopes of correlation lines between 38Ar/40Ar and 36Ar/40Ar
suggests statistically insigniﬁcant diﬀerence in 38Ar/36Ar ratios in Ryugu
samples A0105-04 and C0106-05.

J. Anal. At. Spectrom., 2023, 38, 1785–1797 | 1791

View Article Online

Open Access Article. Published on 21 July 2023. Downloaded on 10/15/2024 6:53:21 PM.
This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence.

JAAS

Paper

Fig. 10 Isotopic composition of Kr released from Ryugu samples
A0105-04 (red diamonds) and C0106-05 (blue circles). Filled symbols
correspond to temperature fractions above ∼700 °C. End member
components (S, A, Q, HL) are the same as in Fig. 7. Kr compositions of N
and G (variable) carried by graphite or SiC are from ref. 33 and 34. Error
bars are 1s. Several points are slightly shifted (less that the symbol size)
to improve clarity.

to these isotopes is probably the least diagnostic and is somewhat confusing (Fig. 11a). Generally all points representing ouranalyses scatter along the mixing line connecting atmosphericand Q values. Coincidently all other end members would shiexperimental points along nearly the same line. Therefore,
estimating relative contributions from potential Xe components
based on this plot alone is nearly impossible. Three other morediagnostic Xe isotope plots are shown in Fig. 11b–d.
Total xenon extractions (i.e., all temperature fractions
combined) are plotted on the mixing line between atmosphericand Q (for clarity not depicted in Fig. 11). However, Xe extracted
from 1260 °C to 1500 °C (typical range for Xe-HL) demonstrates
small but statistically signicant departures from Q-values(Fig. 11b and c). In contrast to lower temperature resolution
laser gas extraction (ref. 22), the observed elevations in lightisotopes 124Xe, 126Xe, 128Xe, and possibly 129Xe indicate the presence of Xe-HL – a presolar Xe component associated with nanodiamond in primitive meteorites. Neon released between 1130 °C
and 1260 °C from sample A0105-04 also indicates the presence ofan HL component; however, no Ne-HL is apparent in the C010605. This is likely due to the signicantly lower temperature resolution of the C0106-05 gas extraction – the 1260 °C Ne extraction
from this sample actually represents gas released from 870 °C to1260 °C. All Xe plots combined reveal no evidences for Solar windor Xe-G from SiC and graphite component.
Fig. 11d shows an excess of 129Xe, evidently from the decay ofprimordial 129I. Interestingly, this excess is observed from 870 °C to 1130 °C, in a narrower temperature range than for Xe-HL,
reaching the maximum at 1000 °C extraction. This diﬀerence

1792 | J. Anal. At. Spectrom., 2023, 38, 1785–1797

Fig. 11 Isotopic composition of Xe released from Ryugu samples
A0105-04 (red diamonds) and C0106-05 (blue circles). Filled symbols
correspond to Xe extracted from 1000 °C to 1500 °C for A0105-04
and from 1260 °C to 1500 °C for C0106-05. Fractions below 1000 °C
tend to group close to the atmospheric value, while fractions above
1000 °C scatter around Q. End member components (SW, A, Q, HL, G)
are the same as in the previous ﬁgures. Pu and U arrows show direction(from Q) to the corresponding ﬁssion compositions. Error bars are 1s.
Some points are shifted by the symbol size to improve clarity.

indicates that Xe-HL and iodine-derived Xe are carried by
diﬀerent mineral phases and step-wise gas extraction is capableof resolving them.

This journal is © The Royal Society of Chemistry 2023

View Article Online

Paper

Open Access Article. Published on 21 July 2023. Downloaded on 10/15/2024 6:53:21 PM.
This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence.

Discussion
Noble gases are retained in natural minerals surprisingly welland are released upon heating only when a host mineral isthermally destructed or goes through a major phase transition.
Below ∼900 °C, extraction of solar wind ions implanted in theoutermost 1 mm grain layers typically occurs. The major noble
gas component Q is released above ∼1000 °C, and then, as
temperature increases, HL (+P6) gases carried by the refractorycarbon phase (nanodiamonds) appear. Radiogenic iodinederived 129Xe inherits its 129I mother isotope site in the crystalline structure of the specic mineral and would be released ina temperature range characteristic of its host phase. Therefore,
isotopic analyses of gases released during multistep heating canprovide information about mineral phases that host released
noble gas components.
The small mass of Ryugu material available for initial analyses limited the number of temperature steps. Recent studies of
Ryugu noble gases26,27 typically used 2–4 laser heating steps,
which is not suﬃcient for satisfactory resolution of various
noble gas components. We studied similarly sized samples, but
our experimental setup allowed us to analyse all noble gas
isotopes in 7 steps for the 82 mg sample (C0106-05) and 11 steps
for the 173 mg sample (A0105-04) with the same or better
precision. As evident from Fig. 1, seven heating steps were
insuﬃcient to resolve two the high-temperature Xe releasepeaks resolved in the 11-step gas extraction.
3
He/4He ratios in both samples decrease with extraction
temperature (Fig. 6), suggesting solar wind fractionation that
increases with the implantation depth. Both samples have bulk
4
He/20Ne ratios of 174 ± 5, lower than the solar wind value(∼660) and closer to the Q value (∼110). Therefore we cannot
exclude a small contribution of He–Q.
Ne data (Fig. 7) exhibit an unmistakable low- and hightemperature component. The 530 °C and 700 °C extractions
from A0105-04 are binary mixtures of solar wind and cosmogenic Ne. As the extraction temperature increases, the solar
wind component is replaced by a mixture of Ne–Q (1000 °C) andcosmogenic Ne (1130 °C). The intermediate 870 °C extraction isa ternary mixture of solar wind, Q, and cosmogenic Ne
components. The 1260 °C point suggests the presence of Ne-HLand indicates that the sample has already lost the solar wind
and the cosmogenic Ne components. Two major Ne releases
from sample C0106-05 demonstrate a similar trend; however,the 7-step extraction cannot resolve the presence of Ne-HL.
Argon likely has two major release peaks – below and above∼1000 °C (Fig. 5). From ∼1000 °C to ∼1500 °C the 36Ar/38Ar
ratios in both samples are uniform and close to the solar windvalue (Fig. 8). At the highest and the lowest temperatures, little
Ar is released, and these ratios are consistent with both, Ar–Q
and atmospheric values. The most noticeable variation in the36
Ar/38Ar ratios of the samples occurs during the gas release at
low temperatures. In this temperature range C0106-05 haseither more atmospheric Ar or more cosmogenic 38Ar thanA0105-04 or both. A good correlation between 36Ar/40Ar and38
Ar/40Ar (Fig. 9) suggests that 40Ar is most likely from

This journal is © The Royal Society of Chemistry 2023

JAAS
atmospheric contamination, not from the K-bearing minerals(40Ar is negligible in the solar wind). There is no statisticallysignicant diﬀerence between the correlation line slopes.
However, a slight diﬀerence in the intercepts of the tting lines
with the 38Ar/40Ar axis supports a higher abundance of spallogenic 38Ar in C0106-05. C0106-05 was collected during thesecond touchdown, about 20 m from the articially created 1–2
m deep crater, and it was expected to contain some ejecta.36
Since the production rate of 38Ar increases with depth, a higher
abundance of spallogenic 38Ar in C0106-05 indicates that thissample represents a deeper layer of the asteroid.
Kr isotopic variations are relatively minor and typically lessdiagnostic for the presence of diﬀerent noble gas components.
Nevertheless, Kr isotopic compositions from low-temperature
extractions tend to scatter around atmospheric values. At
higher temperatures, they shi to Q-values with possible additions of Kr-HL and/or Kr-G (Fig. 10). This separation trend ismore clearly observed in the Xe 3-isotope plots (Fig. 11).
Xe isotope plots are not equally informative. Although three
heavy isotopes are typically measured with signicantly better
precision than the light ones, considering 134Xe/132Xe vs.
136
Xe/132Xe (Fig. 11a) alone can be misleading since nearly all Xe
components lie along the same mixing line between Q andatmospheric values. Light, least abundant, isotopes aremeasured with signicantly lower precision. Nevertheless, the124
Xe/132Xe vs. 126Xe/132Xe experimental points represent a hightemperature release peak that indicates enrichment in 124Xe
and 126Xe. This result is consistent with Xe-HL, the only known
Xe component that can produce the observed shi from Xe–Q
(Fig. 11b). The small excess of 128Xe, also a characteristic featureof Xe-HL, is apparent in 128Xe/132Xe vs. 130Xe/132Xe (Fig. 11c).
Although Xe-G is also enriched in 128Xe, this excess is unlikely
due to the presence of presolar SiC or graphite since they areless abundant then nanodiamonds, the carrier of Xe-HL.
Considering all the noble gas isotopes together, our dataconrm the presence of the HL component in both samples
analysed in this work, hence, resolving the doubts about its
presence in Ryugu samples.27
Xe plot involving odd isotopes (Fig. 11d) shows clear excess
of 129Xe, the decay product of extinct 129I (15.6 Myr), with 129Xe
being released in a more narrow temperature range than Xe–Q,
suggesting diﬀerent host minerals for these two components. A
close relationship between Ryugu and CI chondrites waspreviously suggested based on the nitrogen and noble gases
data.27 Interestingly, the release of radiogenic iodine-derived
129*
Xe in magnetite separated from CI carbonaceous chondrite Orgueil is characterized by two major peaks;37 the lowtemperature one in a 900–1050 °C range, similar to what isobserved here for the Ryugu samples. The presence of magnetite is a marker of aqueous activity. Based on the 53Mn–53Cr
systematics of Ryugu carbonates, the uid–rock interaction
occurred within approximately the rst 2–5 million years ofsolar system history.38,39 Since magnetite is one of the rst
minerals to form during aqueous alteration, studding Xeisotopic systematics in magnetite separated from Ryugu could
further rene the alteration timeline.

J. Anal. At. Spectrom., 2023, 38, 1785–1797 | 1793

View Article Online

JAAS

Open Access Article. Published on 21 July 2023. Downloaded on 10/15/2024 6:53:21 PM.
This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence.

Conclusions
Superior ion utilization in Baur ion source, relatively low massspectrometer volume, very small, stable instrumental massdiscrimination, low memory and background achieved in our
experimental setup allow retrieving more information from the
sub-mg amounts of extraterrestrial material and separation ofnoble gas components by applying multi-step gas extraction
techniques. Particularly, some doubts about the presence ofapparently presolar xenon-HL have been resolved. Presence ofradiogenic iodine-derived 129*Xe in the Ryugu samples ina temperature range observed for the CI chondrite Orgueil,
further support the relationship between Ryugu in CI
chondrites.

Author contributions
Al. M. and O. P. made analytical developments, performed
analyses of asteroid samples delivered by the Hayabusa2
mission and prepared rst version of the manuscript. R. O., K.
S. and Sh. T. developed novel techniques to collect samples
from the asteroid surface, to protect them from atmosphericcontamination (for the rst time since the beginning of sample
return era). R. O., F. K. and T. Y. prepared the samples for thenoble gas analysis. H. Y., To. N, Ta. N., R. O., H. Y., H. N., K. S.
and S. T. coordinated the Ryugu sample initial analysis
campaign. K. Y., T. Y., M. N., A. N., Ak. M., M. A., T. O. and T. U.
contributed the Ryugu sample curation at JAXA. M. Y., T. S., Sa.
T., F. T., S. N., S. W. and Y. T. oversaw the entire operation phaseof the spacecra including two sampling operations.

Conﬂicts of interest
There are no conicts to declare.

Acknowledgements
We are grateful to Dr Charles Hohenberg, the founder of noble gas
facility at Physics Department of Washington University, whorecognised early on the analytical potential of the Baur ion sourceand built the rst mass-spectrometer equipped with this source.
John Stehman helped to write a LabView code to control the mass
spectrometer used in this study. Hayabusa2 YAXA mission
provided unique samples and developed intricate technique to
avoid atmospheric contamination aer landing. We thank Jeﬀrey
Gillis-Davis for his help with revising the manuscript and theanonymous reviewers for their valuable comments and suggestions. This work is supported by NASA grants 80NSSC22K0590,
80NSSC17K0018 and JAXA Hayabusa2 mission.

References
1 M. Ozima and F. A. Podosek, Noble Gas Geochemistry,
Cambridge University Press, Cambridge, 2nd edn, 2002.
2 R. S. Lewis, B. Srinivasan and E. Anders, Host Phase of
a Strange Xenon Component in Allende, Science, 1975, 190,
1251–1262.

1794 | J. Anal. At. Spectrom., 2023, 38, 1785–1797

Paper
3 U. Ott, Planetary and pre-solar noble gases in meteorites,
Chem. Erde, 2014, 74(4), 519–544.
4 H. Y. McSween Jr. and G. R. Huss, Cosmochemistry, Cambridge
University Press, 2010, p. 568, ISBN 978-0-521-87862-3.
5 R. S. Lewis, S. Amari and E. Anders, Interstellar grains inmeteorites: II. SiC and its noble gases, Geochim.
Cosmochim. Acta, 1994, 58, 471–494.
6 R. Wieler, Noble Gas Mass Spectrometry, in, Treatise on
Geochemistry, Elsevier, Oxford, 2nd edn, 2014, vol. 15, pp.
355–373. DOI: 10.1016/B978-0-08-095975-7.01428-5.
7 A. Meshik and O. Pravdivtseva, Noble gas laboratory at
Washington University: history and analytical capabilities,
47th Lunar and Planetary Science Conference, 2016, p. 1681,
https://www.hou.usra.edu/meetings/lpsc2016/pdf/1681.pdf.
8 C. M. Hohenberg, Rev. Sci. Instrum., 1980, 51(8), 1075–1082.
9 S. A. Crowther and J. D. Gilmour, J. Anal. At. Spectrom., 2012,27, 256–269.
10 I. Strashnov, D. J. Blagburn and J. D. Gilmour, A resonanceionization time of ight mass spectrometer witha cryogenic sample concentrator for isotopic analysis of
krypton from extraterrestrial samples, J. Anal. At. Spectrom.,
2011, 26, 1763–1772.
11 G. Avice, A. Belousov, K. A. Farle, S. M. Madzunkov, J. Simcic,
D. Nikolic, M. R. Darrach and C. Sotin, High-precision
measurements of krypton and xenon isotopes with a newstatic-mode Quadrupole Ion Trap Mass Spectrometer, J.
Anal. At. Spectrom., 2019, 34, 104.
12 H. Baur, Numerische Simulation und Praktische Erprobung
einer
Rotation-Symmetrischen
Ionenquelle
fürGasmassenspektrometer, PhD thesis, ETH Zürich, 1980, p.
94, Nr. 6596.
13 F. Albarède, E. Albalat and P. Télouk, Instrumental Isotope
Fractionation in Multiple-Collector ICP-MS, J. Anal. At.
Spectrom., 2015, 30, 1736–1742.
14 N. Vogel, V. S. Heber, H. Baur, D. S. Burnett and R. Wieler,
Argon, krypton, and xenon in the bulk solar wind ascollected by the Genesis mission, Geochim. Cosmochim.
Acta, 2011, 75, 3057–3071.
15 A. Meshik, C. Hohenberg, O. Pravdivtseva and D. Burnett,
Measuring the isotopic composition of solar wind noble
gases, in Exploring the Solar Wind, ed. M. Lasar, InTech,
2012, pp. 93–121, ISBN 978-953-51-0339-4, https://www.intechopen.com/chapters/32533.
16 U. Ott, B. Baecker and M. Trieloﬀ, Multiple ion counting innoble gas mass spectrometry, Workshop on the Modern
Analytical Methods Applied to Earth and Planetary Sciences,
Sopron, Hungary, 2014, LPI Contribution No. 1821, id.4001.
17 S. E. Cox, S. R. Hemming and D. Tootell, The Isotopx NGX
and ATONA Faraday ampliers, Geochronology, 2020, 2,
231–243, DOI: 10.5194/gchron-2-231-2020.
18 Z. A. Palacz, High Precision Calcium Isotope Ratio
Measurements Using Faraday Collectors with ATONA
Ampliers, American Geophysical Union, Fall Meeting,2018, abstract #V43A-01, Bibcode: 2018AGUFM.V43A.01P.
19 R. Moshammer and R. Matthäus, Secondary electron
emission by low energy ion impact, J. Phys., Colloq., 1989,
50(C2), 111–120, DOI: 10.1051/jphyscol:1989220.

This journal is © The Royal Society of Chemistry 2023

View Article Online

Open Access Article. Published on 21 July 2023. Downloaded on 10/15/2024 6:53:21 PM.
This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence.

Paper
20 C. M. Hohenberg, N. Thonnard and A. Meshik, Meteorit.
Planet. Sci., 2002, 37, 257–267, DOI: 10.1111/j.19455100.2002.tb01108.x.
21 R. Okazaki, H. Sawada, S. Yamanouchi, Sh. Tachibana,Y. N. Miura, K. Sakamoto, Y. Takano, M. Abe, S. Itoh,K. Yamada, H. Yabuta, C. Okamoto, H. Yano, T. Noguchi,
T. Nakamura, K. Nagao and The Hayabusa2 SMP Team,
Hayabusa2 Sample Catcher and Container: Metal-Seal
System for Vacuum Encapsulation of Returned Samples
with Volatiles and Organic Compounds Recovered from CType Asteroid Ryugu, Space Sci. Rev., 2017, 208, 107–124,
DOI: 10.1007/s11214-016-0289-5.
22 H. Sawada, R. Okazaki, S. Tachibana, K. Sakamoto,Y. Takano, C. Okamoto, H. Yano, Y. Miura, M. Abe,S. Hasegawa, T. Noguchi and Hayabusa2 SMP Team,
Hayabusa2 Sampler: Collection of Asteroidal Surface
Material, Sci. Rev., 2017, 208, 81–106, DOI: 10.1007/s11214017-0338-8.
23 K. Sakamoto, Y. Takano, H. Sawada, R. Okazaki, T. Noguchi,
M. Uesugi, H. Yano, T. Yada, M. Abe, S. Tachibana and The
Hayabusa2 Project Team, Environmental assessment in theprelaunch phase of Hayabusa2 for safety declaration of
returned samples from the asteroid (162173) Ryugu:
background monitoring and risk management during
development of the sampler system, Earth, Planets Space,2022, 74, 90, DOI: 10.1186/s40623-022-01628-z.
24 A. Meshik, C. M. Hohenberg, O. Pravdivtseva and
D. S. Burnett, Geochim. Cosmochim. Acta, 2014, 127, 326–347.
25 D. V. Bekaert, Y. Marrocchi, A. Meshik, L. Remusat and
B. Marty, Meteorit. Planet. Sci., 2019, 54, 395–414, DOI:
10.1111/maps.13213.
26 R. Okazaki, B. Marty, H. Busemann, K. Hashizume,
J. D. Gilmour, A. Meshik, T. Yada, F. Kitajima,
M. W. Broadle, D. Byrne, E. Füri, M. E. I. Riebe,
D. Krietsch, C. Maden, A. Ishida, P. Clay, S. A. Crowther,L. Fawcett, T. Lawton, O. Pravdivtseva, Y. N. Miura, J. Park,
K. Bajo, Y. Takano, K. Yamada, S. Kawagucci, Y. Matsui,
M. Yamamoto, K. Righter, S. Sakai, N. Iwata, N. Shirai,
S. Sekimoto, M. Inagaki, M. Ebihara, R. Yokochi,
K. Nishiizumi, K. Nagao, J. Lee, A. Kano, M. W. Caﬀee,
R. Uemura, T. Nakamura, H. Naraoka, T. Noguchi,
H. Yabuta, H. Yurimoto, S. Tachibana, H. Sawada,
K. Sakamoto, M. Abe, M. Arakawa, A. Fujii, M. Hayakawa,N. Hirata, N. Hirata, R. Honda, Ch. Honda, S. Hosoda,
Y. Iijima, H. Ikeda, M. Ishiguro, Y. Ishihara, T. Iwata,
K. Kawahara, S. Kikuchi, K. Kitazato, K. Matsumoto,
M. Matsuoka, T. Michikami, Y. Mimasu, A. Miura,
T. Morota, S. Nakazawa, N. Namiki, H. Noda, R. Noguchi,
N. Ogawa, K. Ogawa, T. Okada, C. Okamoto, G. Ono,
M. Ozaki, T. Saiki, N. Sakatani, H. Senshu, Y. Shimaki,
K. Shirai, S. Sugita, Yu. Takei, H. Takeuchi, S. Tanaka,
E. Tatsumi, F. Terui, R. Tsukizaki, K. Wada, M. Yamada,T. Yamada, Y. Yamamoto, H. Yano, Y. Yokota,
K. Yoshihara, M. Yoshikawa, K. Yoshikawa, S. Furuya,
K. Hatakeda, T. Hayashi, Y. Hitomi, K. Kumagai,
A. Miyazaki, A. Nakato, M. Nishimura, H. Soejima,
A. Iwamae, D. Yamamoto, K. Yogata, M. Yoshitake,

This journal is © The Royal Society of Chemistry 2023

JAAS
R. Fukai, T. Usui, H. C. Connolly Jr, D. Lauretta,
S. Watanabe and Y. Tsuda, Noble gases and nitrogen insamples of asteroid Ryugu record its volatile sources andrecent surface evolution, Science, 2022, 379(6634),
eabo0431, DOI: 10.1126/science.abo0431.
27 M. W. Broadley, D. J. Byrne, E. Füri, L. Zimmermann,
B. Marty, R. Okazaki, T. Yada, F. Kitajima, S. Tachibana,K. Yogata, K. Sakamoto, H. Yurimoto, T. Nakamura,
T. Noguchi, H. Naraoka, H. Yabuta, S. Watanabe, Y. Tsuda,
M. Nishimura, A. Nakato, A. Miyazaki, M. Abe, T. Okada,T. Usui, M. Yoshikawa, T. Saiki, S. Tanaka, F. Terui,
S. Nakazawa, H. Busemann, K. Hashizume, J. D. Gilmour,
A. Meshik, M. E. I. Riebe, D. Krietsch, C. Maden, A. Ishida,
P. Clay, S. A. Crowther, L. Fawcett, T. Lawton,
O. Pravdivtseva, Y. N. Miura, J. Park, K. Bajo, Y. Takano,
K. Yamada, S. Kawagucci, Y. Matsui, M. Yamamoto,
K. Righter, S. Sakai, N. Iwata, N. Shirai, S. Sekimoto,
M. Inagaki, M. Ebihara, R. Yokochi, K. Nishiizumi,
K. Nagao, J. I. Lee, A. Kano, M. W. Caﬀee and R. Uemura,
The noble gas and nitrogen relationship between Ryugu
and carbonaceous chondrites, Geochim. Cosmochim. Acta,
2023, 345, 62–73, DOI: 10.1016/j.gca.2023.01.020.
28 Y. N. Miura, R. Okazaki, Y. Takano, K. Sakamoto,
Sh. Tachibana, K. Yamada, S. Sakai and H. Sawada, The
GAs Extraction and Analyses system (GAEA) for immediate
extraction and measurements of volatiles in the Hayabusa2
sample container, Earth, Planets Space, 2022, 74, 76, DOI:
10.1186/s40623-022-01638-x.
29 R. Okazaki, Y. N. Miura, Y. Takano, H. Sawada, K. Sakamoto,T. Yada, K. Yamada, S. Kawagucci, Y. Matsui, K. Hashizume,
A. Ishida, M. W. Broadley, B. Marty, D. Byrne, E. Füri,
A. Meshik, O. Pravdivtseva, H. Busemann, M. E. I. Riebe,
J. Gilmour, J. Park, K. Bajo, K. Righter, S. Sakai,
S. Sekimoto, F. Kitajima, S. A. Crowther, N. Iwata,
N. Shirai, M. Ebihara, R. Yokochi, K. Nishiizumi, K. Nagao,
J. Ik Lee, P. Clay, A. Kano, M. W. Caﬀee, R. Uemura,
M. Inagaki, D. Krietsch, C. Maden, M. Yamamoto,L. Fawcett, T. Lawton, T. Nakamura, H. Naraoka,
T. Noguchi, H. Yabuta, H. Yurimoto, Y. Tsuda,
S. Watanabe, M. Abe, M. Arakawa, A. Fujii, M. Hayakawa,N. Hirata, N. Hirata, R. Honda, C. Honda, S. Hosoda,
Y. Iijima, H. Ikeda, M. Ishiguro, Y. Ishihara, T. Iwata,
K. Kawahara, S. Kikuchi, K. Kitazato, K. Matsumoto,
M. Matsuoka, T. Michikami, Y. Mimasu, A. Miura,
T. Morota, S. Nakazawa, N. Namiki, H. Noda, R. Noguchi,
N. Ogawa, K. Ogawa, T. Okada, C. Okamoto, G. Ono,
M. Ozaki, T. Saiki, N. Sakatani, H. Senshu, Y. Shimaki,
K. Shirai, S. Sugita, Y. Takei, H. Takeuchi, S. Tanaka,
E. Tatsumi, F. Terui, R. Tsukizaki, K. Wada, M. Yamada,T. Yamada, Y. Yamamoto, H. Yano, Y. Yokota,
K. Yoshihara, M. Yoshikawa, S. Furuya, K. Hatakeda,
T. Hayashi, Y. Hitomi, K. Kumagai, A. Miyazaki, A. Nakato,
M. Nishimura, H. Soejima, A. Iwamae, D. Yamamoto,K. Yogata, M. Yoshitake, R. Fukai, T. Usui, T. Ireland,
H. C. Connolly Jr, D. S. Lauretta and S. Tachibana, First
asteroid gas sample delivered by the Hayabusa2 mission: A

J. Anal. At. Spectrom., 2023, 38, 1785–1797 | 1795

View Article Online

Open Access Article. Published on 21 July 2023. Downloaded on 10/15/2024 6:53:21 PM.
This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence.

JAAS
treasure box from Ryugu, Sci. Adv., 2022, 8, eabo7239, DOI:
10.1126/sciadv.abo7239.
30 O. Pravdivtseva, F. L. H. Tissot, N. Dauphas and S. Amari,Evidence of presolar SiC in the Allende Curious Mariecalcium–aluminium-rich inclusion, Nat. Astron., 2020, 4,
617–624.
31 T. Morota, S. Sugita, Y. Cho, M. Kanamaru, E. Tatsumi,
N. Sakatani, R. Honda, N. Hirata, H. Kikuchi, M. Yamada,
Y. Yokota, S. Kameda, M. Matsuoka, H. Sawada, C. Honda,
T. Kouyama, K. Ogawa, H. Suzuki, K. Yoshioka,
M. Hayakawa, N. Hirata, M. Hirabayashi, H. Miyamoto,T. Michikami, T. Hiroi, R. Hemmi, O. S. Barnouin,
C. M. Ernst, K. Kitazato, T. Nakamura, L. Riu, H. Senshu,
H. Kobayashi, S. Sasaki, G. Komatsu, N. Tanabe, Y. Fujii,
T. Irie, M. Suemitsu, N. Takaki, C. Sugimoto, K. Yumoto,
M. Ishida, H. Kato, K. Moroi, D. Domingue, P. Michel,
C. Pilorget, T. Iwata, M. Abe, M. Ohtake, Y. Nakauchi,
K. Tsumura, H. Yabuta, Y. Ishihara, R. Noguchi,
K. Matsumoto, A. Miura, N. Namiki, S. Tachibana,M. Arakawa, H. Ikeda, K. Wada, T. Mizuno, C. Hirose,
S. Hosoda, O. Mori, T. Shimada, S. Soldini, R. Tsukizaki,
H. Yano, M. Ozaki, H. Takeuchi, Y. Yamamoto, T. Okada,Y. Shimaki, K. Shirai, Y. Iijima, H. Noda, S. Kikuchi,
T. Yamaguchi, N. Ogawa, G. Ono, Y. Mimasu,
K. Yoshikawa, T. Takahashi, Y. Takei, A. Fujii,
S. Nakazawa, F. Terui, S. Tanaka, M. Yoshikawa, T. Saiki,
S. Watanabe and Y. Tsuda, Sample collection fromasteroid (162173) Ryugu by Hayabusa2: Implications forsurface evolution, Science, 2020, 368(6491), 654–659, DOI:
10.1126/science.aaz6306.
32 R. Okazaki, S. Yamanouchi, K. Shimada, A. Baba, F. Kitajima
and T. Yada, Methods and tools for handling,transportation, weighing, and pelletization applied to theinitial analysis of volatile components in the Hayabusa2
samples, Earth, Planets Space, 2022, 74, 190, DOI: 10.1186/
s40623-022-01747-7.
33 G. R. Huss, A. P. Meshik, J. B. Smith and C. M. Hohenberg,
Presolar diamond, silicon carbide, and graphite incarbonaceous chondrites: implications for thermal
processing in the solar nebula, Geochim. Cosmochim. Acta,
2003, 67(24), 4823–4848, DOI: 10.1016/j.gca.2003.07.019.
34 R. S. Lewis, B. Srinivasan and E. Anders, Host phase ofa strange xenon component in Allende, Science, 1975, 190,
1251–1262.
35 A. Meshik, J. Mabry, C. Hohenberg, Y. Marrocchi,
O. Pravdivtseva, D. Burnett, C. Olinger, D. Reisenfeld and
A. J. G. Jurewicz, Constraints on neon and argon isotopic
fractionation in solar wind, Science, 2007, 318, 433–435,
DOI: 10.1126/science.1145528.
36 S. Tachibana, H. Sawada, R. Okazaki, Y. Takano,
K. Sakamoto, Y. N. Miura, C. Okamoto, H. Yano,
S. Yamanouchi, P. Michel, Y. Zhang, S. Schwartz,
F. Thuillet, H. Yurimoto, T. Nakamura, T. Noguchi,
H. Yabuta, H. Naraoka, A. Tsuchiyama, N. Imae,
K. Kurosawa, A. M. Nakamura, K. Ogawa, S. Sugita,
T. Morota, R. Honda, S. Kameda, E. Tatsumi, Y. Cho,
K. Yoshioka, Y. Yokota, M. Hayakawa, M. Matsuoka,

1796 | J. Anal. At. Spectrom., 2023, 38, 1785–1797

Paper
N. Sakatani, M. Yamada, T. Kouyama, H. Suzuki,
C. Honda, T. Yoshimitsu, T. Kubota, H. Demura, T. Yada,
M. Nishimura, K. Yogata, A. Nakato, M. Yoshitake,
A. I. Suzuki, S. Furuya, K. Hatakeda, A. Miyazaki,
K. Kumagai, T. Okada, M. Abe, T. Usui, T. R. Ireland,
M. Fujimoto, T. Yamada, M. Arakawa, H. C. Connolly Jr,
A. Fujii, S. Hasegawa, N. Hirata, N. Hirata, C. Hirose,
S. Hosoda, Y. Iijima, H. Ikeda, M. Ishiguro, Y. Ishihara,
T. Iwata, S. Kikuchi, K. Kitazato, D. S. Lauretta,
G. Libourel, B. Marty, K. Matsumoto, T. Michikami,
Y. Mimasu, A. Miura, O. Mori, K. Nakamura-Messenger,
N. Namiki, A. N. Nguyen, L. R. Nittler, H. Noda,
R. Noguchi, N. Ogawa, G. Ono, M. Ozaki, H. Senshu,
T. Shimada, Y. Shimaki, K. Shirai, S. Soldini, T. Takahashi,
Y. Takei, H. Takeuchi, R. Tsukizaki, K. Wada,
Y. Yamamoto, K. Yoshikawa, K. Yumoto, M. E. Zolensky,
S. Nakazawa, F. Terui, S. Tanaka, T. Saiki, M. Yoshikawa,
S. Watanabe and Y. Tsuda, Pebbles and sand on asteroid(162173) Ryugu: In situ observation and particles returned
to Earth, Science, 2022, 375, 1011–1016, DOI: 10.1126/
science.abj8624.
37 O. Pravdivtseva, A. N. Krot and C. M. Hohenberg, I-Xe datingof aqueous alteration in the CI chondrite Orgueil: I.
Magnetite and ferromagnetic separates, Geochim.
Cosmochim. Acta, 2018, 227, 38–47, DOI: 10.1016/
j.gca.2018.02.004.
38 K. A. McCain, N. Matsuda, M.-C. Liu, K. D. McKeegan,
A. Yamaguchi, M. Kimura, N. Tomioka, M. Ito, N. Imae,
M. Uesugi, N. Shirai, T. Ohigashi, R. C. Greenwood,
K. Uesugi, A. Nakato, K. Yogata, H. Yuzawa, Y. Kodama,
K. Hirahara, I. Sakurai, I. Okada, Y. Karouji, S. Nakazawa,T. Okada, T. Saiki, S. Tanaka, F. Terui, M. Yoshikawa,
A. Miyazaki, M. Nishimura, T. Yada, M. Abe, T. Usui,
S. Watanabe and Y. Tsuda, Early uid activity on Ryugu
inferred by isotopic analyses of carbonates and magnetite,
Nat. Astron., 2023, 7, 309–317. https://www.nature.com/
articles/s41550-022-01863-0.
39 T. Yokoyama, K. Nagashima, I. Nakai, E. D. Young, Y. Abe,
J. Aléon, C. M. O. ’D. Alexander, S. Amari, Y. Amelin,
K. Bajo, M. Bizzarro, A. Bouvier, R. W. Carlson,
M. Chaussidon, B.-G. Choi, N. Dauphas, A. M. Davis, T. Di
Rocco, W. Fujiya, R. Fukai, I. Gautam, M. K. Haba,
Y. Hibiya, H. Hidaka, H. Homma, P. Hoppe, G. R. Huss,
K. Ichida, T. Iizuka, T. R. Ireland, A. Ishikawa, M. Ito,
S. Itoh, N. Kawasaki, N. T. Kita, K. Kitajima, T. Kleine,
S. Komatani, A. N. Krot, M.-C. Liu, Y. Masuda,
K. D. McKeegan, M. Morita, K. Motomura, F. Moynier,
A. Nguyen, L. Nittler, M. Onose, A. Pack, C. Park, L. Piani,
L. Qin, S. S. Russell, N. Sakamoto, M. Schönbächler,
L. Taa, H. Tang, K. Terada, Y. Terada, T. Usui, S. Wada,
M. Wadhwa, R. J. Walker, K. Yamashita, Q.-Z. Yin,
S. Yoneda, H. Yui, A.-C. Zhang, H. C. Connolly Jr,
D. S. Lauretta, T. Nakamura, H. Naraoka, T. Noguchi,
R. Okazaki, K. Sakamoto, H. Yabuta, M. Abe, M. Arakawa,
A. Fujii, M. Hayakawa, N. Hirata, Na. Hirata, R. Honda,
Ch. Honda, S. Hosoda, Y. Iijima, H. Ikeda, M. Ishiguro,
Y. Ishihara, T. Iwata, K. Kawahara, S. Kikuchi, K. Kitazato,

This journal is © The Royal Society of Chemistry 2023

View Article Online

Open Access Article. Published on 21 July 2023. Downloaded on 10/15/2024 6:53:21 PM.
This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence.

Paper
K. Matsumoto, M. Matsuoka, T. Michikami, Y. Mimasu,
A. Miura, T. Morota, S. Nakazawa, N. Namiki, H. Noda,
R. Noguchi, N. Ogawa, K. Ogawa, T. Okada, Ch. Okamoto,
G. Ono, M. Ozaki, T. Saiki, N. Sakatani, H. Sawada,
H. Senshu, Y. Shimaki, K. Shirai, S. Sugita, Y. Takei,
H. Takeuchi, S. Tanaka, E. Tatsumi, F. Terui, Y. Tsuda,
R. Tsukizaki, K. Wada, S. ichiro Watanabe, M. Yamada,T. Yamada, Y. Yamamoto, H. Yano, Y. Yokota,

This journal is © The Royal Society of Chemistry 2023

JAAS
K. Yoshihara, M. Yoshikawa, K. Yoshikawa, S. Furuya,
K. Hatakeda, T. Hayashi, Y. Hitomi, K. Kumagai,
A. Miyazaki, A. Nakato, M. Nishimura, H. Soejima,
A. Suzuki, T. Yada, D. Yamamoto, K. Yogata, M. Yoshitake,
S. Tachibana and H. Yurimoto, Samples returned from theasteroid Ryugu are similar to Ivuna-type carbonaceous
meteorites, Science, 2022, 379, 6634, DOI: 10.1126/
science.abn7850.

J. Anal. At. Spectrom., 2023, 38, 1785–1797 | 1797