ðà
¬f¯CgJ©çÌ¿ÌúËõgOtB[ðpµ½ªÍ
R¾

såwåw@w¤Ènv |f¯ÈwêU§606_8502 ss¶ækìÇª¬FT¸@ÍâÔ³ª¬f¯CgJ\Ê©çÌæµ½÷±qÌúªÍª2011NÉ¨±Èíê½B±êÉæèCS
^Ì½ËXyNgðàÂ¬f¯ÍF»ðó¯½ÊRhCg©çÈéÆ¢¤C±êÜÅÉè³êÄ¢½¦ÎÆ¬f¯ÆÌÎÖWª³µ©Á½±ÆªÅIIÉmØ³êC¦ÎÌN¹ÉI~ªÅ½ê½¾¯ÅÈ­CF»ðÍ¶ßÆ·é¬f¯\ÊãÅÌlXÈvZXª¾ç©É³ê½BäXÌ¤O[vÍCSPring­8 É¨¢ÄúËõðp¢½}CNgOtB[ðp¢ÄC±êçÌ±qÌ 3 ³\¢ðTu~NÌóÔªð\Å¾ç©Éµ½B±ÌÆ«CFe Ì K zû[ð²Þ 2 ÂÌÙÈÁ½ X üGlM[Å¯êTvðBe·é±ÆÉæèCèÊIÈz¨Ì 3 ³ªzð¾é±ÆªÅ«½ianalytical dual­energy micro­tomographyjB±êÉæèCgJÌ÷±qªÊRhCgiLL RhCgjÉÎ·é±ÆCÜ½±qÌ 3 ³O`©çÍ±qÍÕËjÐÅ

èC±q\ÊÌêÍÕ³êÄ¢é±ÆÈÇð¾ç©Éµ½BÜ½±ÌñjóªÍðÍâÔ³T

vúªÍÌî{íªÆµÄ¨¦C±ÌãÉ¨±Èíê½jóªÍÌ½ßÉÇÌûüÅWÉTvðßÄØf·é©Æ¢¤f[^ðñµC÷×È±q©çÅåÀÌîñðø¦æ­¾é±ÆªÅ«½B¯ðN¹ÆµÄ¢éÆl¦çêÄ«½B¬f¯Ì\Ê¨¿

1. Í¶ßÉ

ÍC¦ÎÌßÔO`Âõ½ËXyNgÆär·é±Æ¬f¯Í¾zn`¬Éf¯ÉÜÅå«­ÈêÈ©Á½Éæèè³êéªCCgJÍ S ^¬f¯ÅÏª³ê¬VÌÅC¾zn`¬ÌîñðcµÄ¢éÆl¦çêÄé½ËXyNgð¦µCÍâÔ³T¸@ÉæéßÚÏª¢éBú{Fqó¤J­@\iJAXAjÌÍâÔ³TÉæèÊRhCg¦ÎÌÅàÆ­É LL5é¢¸@Í2003N 5 ÉÅ¿ã°çêC2005N 9 ÉCgJ

Í LL6 RhCgÆÄÎêé¦ÎÉÞ·é±Æªw

Æ¼t¯çê½¬³ÈTCYi535~294~209 mjÌ¬E³ê½2)Bµ©µÈªçCS ^¬f¯ÆÊRhCµ C ¯ N 11  Ü Å Ï ª ð ¨ ± È ¤ Æ Æ àg¦ÎÌ½ËXyNgÍ®SÉÍêv¹¸C»Ìá¢ÍÉ1_2)C¬f¯\ÊÌ MUSES_C Regio ÆÄÎêé÷×±uF»£13) ÆÄÎêé¬f¯\ÊÅÌvZXÉNöqÅ¢íê½næ©çTvÌæð¨±ÈÁ½3)B2010µÄ¢éÆl¦çêÄ¢éB]ÁÄCÍâÔ³Tv

N 6 CnúªÍÌæêÌÚIÍCCgJÌ\Ê¨¿ª{ÉFf¯ÉÉAÒµ½T¸@ÍåCÉËüµÄR¦s«½ªCTvJvZÍ³ñû³ê½B±êÍ¬»ðó¯½ÊRhCgiLL RhCgjÅf¯©çßÄTv^[³ê½àÌÅé¾¯Åé©ÉÂ¢Ä¼ÚIÈmØð^¦é±ÆÉÈ­CiA|væÉivæjÉ¢ÅnOVÌ©

ÍâÔ³TvÍnÌåCâL@¨Éõ³êÄ¢ÈçÌæ³ê½ 2 ÔÚÌSXif¯Ì\yFâ¬f¢SX±qÅ¯\ÊÅÍ¬VÌªÕËµÄÅ«½×©¢»ðêÊÉÓ¡ÉÂ¢ÄÌîñð^¦Ä­êéÍ¸Å·éjÌTvÅàéBJAXA ÌLèC¬f¯ÅÌSXÌ`¬âi»éB[V{

ÝÅTvJvZªJ³ê4)C2012N 9 _ÅCgJN¹Æl¦çêé±qÍ2000Âöx©o³êÄ¢éB»Ì½­Í10 mm ÈºÌTCYÅÅåÅà300 mm ö
xÌ÷±qÅ

Á½BÜ½CéB±êçÌÌ¢­Â©Ì±qªàÌ

2. ÍâÔ³TvúªÍÆ»ÌTv
MÒª[_[ÆÈÁ½åwR\[VA`[ÌúªÍÅÍCç©¶ßõµÄ¢½t[iFig. 1jÉlXÈ¤@ÖÉzz³êC2011N 1 ©ç12É©¯]ÁÄCzª³ê½ärIå«Èñ60±qi30_180 mmjÄúªÍª¨±Èíê½4_12)BÜ½2012N 6 ©çÍC

ð 1 ±q¸ÂªÍµ½BFig. 1 É¨¢ÄEÌ 3 ÂÌt[ÛöåÉæéÚ×ªÍªJn³êÄ¢éBÍCnåCi_fÉóKXjân

L@¨ÌõªÅ¬ÖÌºªÏª³ê½¦ÎÌO¹ðÍâõw½ËX

À É È é æ ¤ É C F   » Ì T ¸5) C ó K X ¯ Ê Ì ª

yNgªèÉæèCÙÆñÇÌ¦Îiñ99.9÷jÍ¬fÍ6)CL@¨ÌªÍ7,8)Ì½ßÉÂXÉªÍð¨±ÈÁ½à

n328  úËõ Nov. 2012 Vol.25 No.6
(C) 2012 The Japanese Society for Synchrotron Radiation Researchðà ¡ ¬f¯CgJ©çÌ¿ÌúËõgOtB[ðpµ½ªÍFig. 1(Color online) A ow chart for the preliminary examinationof Hayabusa samples. Each analysis was made grain­by­grain. Three ows for ``space weathering'', ``noble gases''and ``organic materials'' were specically made to minimize
terrestrial contamination from the atmosphere (oxygen andnoble gasses) and organic materials. Some particles wereanalyzed in multiple ows. See SOM in4) for details of themainstream ow analysis.

Fig. 2 (Color online) Summary of the preliminary examination
results of Hayabusa samples, where interior and surface
processes throughout the solar system history are shown.
(Original drawing of Dr. S. Tachibana of Hokkaido Univer­sity was slightly modied).

êûCSXÆµÄÌCgJ±qÌªÍÉæèC¦Î©çÅÍ¾çêÈ¢îñª¾çê½BCgJ\ÊÍCÌÅ

éBL@¨ªÍÍ±q\ÊÉÂ¢Ä¨±ÈÁ½ãC

¬VÌâ÷¦ÎÌÕË¾¯ÅÈ­C¾zââÍFüÌ«qúË»ªÍðp¢½³fªÍ9)ð¨±ÈÁ½B»ÌÆËðó¯Ä¢éBÌSX±qÅÍC»Ì±q\Ê¼Ì½­Ì±qÉÂ¢ÄÍCCXg[ÆÄñ¾t

É100 nm öxÌúÝðàÂà®Sim±qðÜÞñ»¿[É¨¢Ä÷¬±q©çÅåÀÌîñðø«o·½ß

]_wª©o³êÄ¨èC±êªÌ½ËXyNgÌ

ÉCñjóªÍiX ü CT ªÍ10)CX üñÜªÍ4)j©çÏ»iÔ»¨æÑÃ»jðà½çµ½´öÅjóªÍi±qfÊÌ¸^¨æÑ§ß^dq°÷¾Ï@çêÄ¢é13) B±Ìæ¤ÈÏ»ÍC\ÊÖÌ÷¦ÎÕ¨æÑÇ³fªÍ4)CñCI¿ÊªÍÉæé¯ÊÌËâ¾zÆËÉNö·éÆl¦çêCF»ÆÄÎêé±Æªm11) jÖÆªÍª¨±Èíê½BMÒÌ¤O[vÄ¢éB¡ñÌ§ß^dq°÷¾iTEMjðp¢½ªÍÍC±ÌCXg[ÅÅÉ¨±Èíê½ñjóªÉæèCCgJ±q\ÊÉàSÉxÞim±qðÜÞñ

ªÍÍÆµÄCX ü CTiúËõgOtB[jðp¢½±»¿]_wª©o³êC¬f¯ÅÌF»ªÀØ³êqÌ 3 ³\¢ðß½10) BêAÌ¬ÊiFig. 2jÍCT

½5)B±êÉæèCåCÌÈ¢VÌÌ½ËXyNgðÏCGXÉ 6 ÂÌ_¶4_6,9_11)ÆµÄ­\³êCTCG

»³¹é´öðêÊIÉà¾Å«é±Æª¦³ê½BÜ½

XÌ2011NÌu[NX[ÉàIÎê½B

óKX¯ÊÌªÍÉæèC±qÉÅ¿Üê½¾zóKCT ðp¢½ªÍÌÚ×ðq×éi4 ÍjOÉC±±ÅÍêAÌúªÍÌ¬ÊÉÂ¢ÄC»ÌTvðq×éB

X¬ªªo³êC±qªCgJÌÅà\ÊÉØÝµ½ÔXP[Í150NöxÅ

é±ÆCÜ½âÍFüNúªÍÉ¨¢ÄCz¨Ì³fÉ¯ÊÌg¬â[hg¬C¹ÌóKXÍoÅ«È©Á½±Æ©çC±qªSXâÎgDÉæèCÍâÔ³ªñûµ½TvÍ¬f¯CwàÉØÝµ½ÔXP[ÌãÀª300NöxÅèC»Ì½­Í LL5

é±Æªª©Á½6)B±êçÌNãÍCSXÌØÝé¢Í LL6 É®·éÊRhCg¦ÎÉÞ·éÔXP[i10­NöxjÆä×Ä³|IÉZ­C¬

gJ\ÊÉ¶ÝµÄ¢½±qÅ¨¿Åé±Æªª©Á½4,9_11) B2 íÞÌz¨ÔÌ³fªz©çèµ½CgJ±q\¬¨¿ÌÅB·xÍ
800
CöxÅ

èCÁÅúËüjíÅ

é 26Al Éæé¬f¯ÌÁMfðàÆÉµÄC20 km ÈãÌ¼aðàÂC
gJêVÌàÅMÏ¬ðó¯½àÌÅéÆl¦çêéBÜ½ 4 ÍÅÚµ­q×éæ¤ÉCCgJ±qÌ 3 ³`ó©çÍC±qÍÕËjÐÅ

èC±q\ÊÌêÍÕ³êÄ¢é±ÆÈÇªí©Á½10)B

é±Æªí©

Á½4)BÜ½CêÌTv±qÍMÏ¬xÌá¢ LL4
ÌàÌÅ³È¬f¯ÌÁ¥Å

è4,10)C±êçÌ±qÍêVÌÌ\ÊÉÁ½àÌÆl¦çêéBêVÌªÊÌVÌÌÕËÉæèjó³êCjÐÌêªÄWÏµÄ»ÝÌCgJÆÈÁ½Æ¢

3. úËõgOtB[ÆÍâÔ³TvÖÌp
X ügOtB[iX ü CTjÍ X üª¨Ìð§ß·¤upCVÌf1)ðÀØµCæèïÌIÈ`éÛÉ¾çêézûâÊVtgÈÇÌîñðàÆÉC¨ð^¦½iFig. 2jB

ÌÌà\¢ð¾éè@Å

éBA±IÈfW^fw

úËõ Nov. 2012 Vol.25 No.6  329

DmkrDtjwj(2)Æ È è C 2 Â Ì G l  M [ Å B e µ ½ CT  Ì · ª i Dm ÌóÔªzjÍ³f j ÌóÔªzð½fµ½àÌÆÈéBµ©µÈªçC§xÍ³fg¬ÌÖÅàèCµ§ÉÍ±Ìû@ÅèÊIÈ³fg¬ð³mÉ¾é±ÆÍïµ¢B³çÉ½Æ¦èÊIÈ³fg¬ð¾çê½ÆµÄà C ·ª  Ìî ñ Í 1  ³I Å

è C ÙÈ é ¨ ¿Ô ÌI[o[bvÍð¯çêÈ¢BTsuchiyama et al.10,18)ÍCÍâÔ³TvÌúªÍÉ¨¢ÄCÁèÌ³fÌ
X üzû[ð²ñ¾ 2 ÂÌGlM[ÅÌ CT BeÉæFig. 3(Color online) Mass attenuation coecients (MAC) of ele­ments plotted against x­ray photon energy. E1 and E2 areenergies just below and above the K­absorption edge energyof Fe (7.112 keV).

èC½­Ì¨¿iÍâÔ³TvÅÍz¨jÌ¯èªÅ«é±Æð¦µ½B
ÍâÔ³TvÌæ¤Èf¯¨¿inÌ}g¨¿àÜßÄjÌåv³fg¬ÍCö­«³fð¢½¾z
nÉ¨¯é³f¶ÝxÉß­CMg, Si, Fe, O ÉxñÅ¨

iCT jðÏÝdËé±ÆÉæèCTCYÈÇèÊIÈ

èCS, Al, Ca, Na, Ni ¨æÑ Cr ª±êÉÂÃ­19)B±Ìô½wîñðàÂ 3 ³à\¢ª¾çêéB¢tæ¤È³fg¬ð½fµÄCÍâÔ³TvâÊR

bNX§xÆ±Â«ðàÂúËõÌ X üðp¢é±ÆÉhCgÌåv\¬z¨Í Table 1 É°½æ¤ÈàÌÆæèC¢ S/N äÆóÔªð\ðàÂ CT ª¾çêéÈéB4 ÂÌåv³fÌÅÆ­Éd¢³fÍ Fe Å éBiá¦Î14) jBêûCtl][v[gðà¿¢½

Fe Ì K zû[ÌGlM[Í7.112 keV Å

X ü°÷õwnÉæè X ür[ðgåµÄCTu~N²ñ¾ 7 keV Æ 8 keV ÅÌåv\¬z¨Ì LAC lª Fig.

ÌóÔªð\ðàÂ CT ð¾é±ÆªÅ«éiá¦

4 É v  b g ³ ê Ä ¢ é B á ¦ Î C © ñ ç ñ Î m Ol F

Î15)jB(Mg, Fe)2 SiO4 nÍtHXeCgmMg2SiO4 nÆt@X üÌzûÌîñðàÆÉµ½zûgOtB[ÅèC±êðCCgmFe2SiO4 nð[¬ªÆ·éÅnÌÅ

èCÍCX üÌüzûWiLACjÌóÔªzÆµÄ¨ÌÌ

Mg#([Mg]/{[Mg]{[Fe]}) Éæè LAC lÍÏ»·éB

fW^fwiCT jª¾çêéB¨¿Ì LAC lCmC

Fe zû[æè¢ 8 keV ÅÍ Mg#Ìáºi·Èí¿ Fe

ÍCr ð§xCti (E) ð³f i Ì¿ÊzûWiX üÌGÊÌÁjÉ]ÁÄ LAC lªå«­Á·éÌÉÎµÄCéFFig. 3jCwi ð³f i ÌdÊlM[CECÌÖÅFe zû[æèá¢ 7 keV ÅÍ Mg#ÌáºÅ LAC lÍÜèÁµÈ¢iFig. 4jB¯lÌ±ÆÍ Ca ÉRµ¢PÎª¦Æ·éÆ

mLPxF(Mg, Fe)SiO3 nÅà¢¦C2 ÂÌÅnÌÌ LAC

mrti(E)wi(1)

lÍ 2 ³IÉI[o[bv·éBµ©µÈªçCÍÅ\³êéBPF X üðp¢éÆiúËõ©çÍt

Ì Mg#ÍÙÚêèÌlðÁÄ¨èCFig. 4 Å¦³êéæi

âÔ³TvÉÜÜêé©ñçñÎÆ Ca ÉRµ¢PÎbNXÌPF X üª¾çêéjCX üÌGlM[ÉÎ¤É¼ÒðeÕÉæÊ·é±ÆªÅ«½BêûCCa Éxµ½èÊIÈ LAC lðàÂ CT ª¾çêC±êæè¨ÞPÎmHPxF(Ca, Mg, Fe)SiO3 nÅÍCMg#¾¯ÅÈ¿Ì¯èªÂ\ÆÈé16)Bµ©µÈªç(1)®©çí©é­ Ca ÊªÏíé±ÆÉæÁÄà LAC lÍÏ»·éBáæ¤ÉC§xÆ³fg¬ÌgÝí¹ÉæèêÊIÉÍÙ

¦ÎCMg Ì[¬ªmiCa, Mg)SiO3nÅÍCMg æèd³
é Ca ÊÌÁÉæèCÆ­ÉGlM[Ìá¢ 7

ÈÁ½¨¿ªÙÚ¯¶ LAC lðàÂÌÅCPêÌ LAC

fÅlÌÝ©ç¨¿ð¯è·éÉÍÀEªkeV ÅÌ LAC lÌÁª 8 keV Éä×Äå«­ÈèCFe

éB

2 ÂÌÙÈÁ½ X üGlM[ðIñÅ¯êÌTv

ÊÌÁÆÍÙÈéghðàÂB±Ìæ¤ÉµÄCðBe·é±ÆÉæèCãLÌâèðð·é±ÆªÅFig. 4 É¨¢ÄCz¨Ì Fe ÊªÁ·éÆ LAC lÍã

éÁèÌ³f j ÉÚûââEÖCêû Fe Ì­È¢z¨É¨¢Ä S, Ca, Cr È

µC»Ì³fÌ X üzû[ÌGlM[Ì¼ºÆ¼ãÌÇÌ Si, Mg æèd¢³fÊªÁ·éÆ LAC lÍEûGlM[i E1 Æ E2 jÅBe·éiFig. 3jB±Ì 2 ÂÌââãÖÆÏ»·é±ÆÉÈèC½­Ìz¨ð¯è·é±«éB·ª@iá¦Î17)jÅÍC

GlM[Å LAC lÌ·ªCDmm( E2 )|m( E1 )CðÆÆªÂ\ÆÈéBÜ½CÅnÌðÂ­éz¨Ì»wg¬

Úµ½³fÈOÅÍ E1 kE2 ÈÌÅ Dti k0 ÆÈ

iá¦Î Mg#jàèÅ«C±Ìè@ð analytical dual­éÆCéÌÉÎµÄCDtj ÍLÀÌlðÆéB]ÁÄ(1)®æèenergy tomography ÆÄñ¾18)BÈãÉq×½æ¤ÉC±Ìè@ÍTvÌ\¬z¨

330  úËõ Nov. 2012 Vol.25 No.6

ðà ¡ ¬f¯CgJ©çÌ¿ÌúËõgOtB[ðpµ½ªÍTable 1mineralRepresentative minerals in ordinary chondrites and Hayabusa samples

abbriviation

formulacrystal systemÞ

end member

abbriviation

formulaolivineOl(Mg, Fe)2SiO4

Orthforsterite
fayalite

FoFa

Mg2SiO4
Fe2SiO4

low­Ca pyroxene

LPx(Mg, Fe)SiO3

Orth, Monoenstatite
ferrosilite

En
Fs

MgSiO3
FeSiO3high­Ca pyroxene

HPx(Ca, Mg, Fe)SiO3

Monodiopsite

Þ
DiÞ
Þ
HdÞ
Ab

CaMgSi2O6

hedenbergite
albiteCaFeSi2O6
NaAlSi3O8

anorthiteAn

CaAl2Si2O8

plagioclase

Pl(Na, Ca)Al(Al, Si)Si2O8

Mono, Triapatitemerrillite

ÞÞ
CPÞ
Þ
CPÞÞ

Ca5(PO4)3(F, Cl, OH)
Ca9NaMg(PO4)7

Hex
Tri

chromitetroilite

Chm
Tr

Cub
Hex

kamacite

Kam

FeCr2O4FeS
a­(Fe, Ni)

taeniteTaeg­(Fe, Ni)

Cub

Cub

ÞCub: cubic, Hex: hexagonal, Orth: orthorhombic, Mono: monclinic, Tri: triclinicÞÞEn and Fs are also endmembers.
ÞÞÞApatite and merrillite are abbreviated as CP (Ca phoshate).

texp (|mx)(3)]ÁÄCCT Ä\¬ÉÅàKØÈ S/N äª¾çêéÌÍ mxk1 ÌÆ«ÆÈéBLAC lÍ(1)®©çí©éæ¤É
X üÌGlM[ÌÖÅèÚ·é³fÌzû[ÌG l  M [ ð E ÞÆ · é Æ C K Ø È T  v  T C Y Ím(E Þ)|1 öxÆÈéBÍâÔ³TvÌêC»ÌÅKTCYÍ¨¨æ» 5`100 mm ÅTCYÆ¯öxÅ

èCÀÛÌTv

Á½B±Ìè@ÍÍâÔ³Tv¾¯ÅÈ­ClXÈªìÉ¨¢ÄàC¡Ì¨¿iz¨jðÜÞTvÉKpÂ\ÅÉC
Fig. 4(Color online) A two­dimensional histogram of linear at­
tenuation coecient (LAC) values at 7 and 8 keV for an
Itokawa particle (RA_QD02_0013). Logarithm of the num­
ber of voxels is shown as a rainbow scale (from 0 to the max­imum). Solid symbols show LAC values calculated from themean chemical compositions of minerals of Itokawa
particles4). LAC values of olivine, pyroxene and plagioclasesolid solutions are also shown as open symbols. Numbers
along forsterite­fayalite, enstatite­ferrosilite, enstatite­diop­side and albite­anorthite joins are the forsterite, enstatite,wollastonite and albite contents (in mol.÷), respectively.
Abbreviations for minerals are the same as Table 1.

éBãÌc_©çí©éæ¤Ú·é³fª Fe æèày¢ÆKØÈTvTCYÍ¬³­Èè·¬ÄµÜ¢»ÀIÅÈ­ÈéªCFe æèàd¢³fÅÍTvTCYÍå«­ÈèCLøÈè
@ÅéÆ¢¦éB

4. }CN CT ðp¢½CgJ±qÌ
3 ³\¢
P 3 ³à\¢ðàÆÉ}CN CT ªÍÌÚIÍCò

¦ÎÆÌäræèCgJÌ\Ê¨¿ð¾ç©É·é±ÆC
Q 3 ³±q`óðàÆÉSX`¬Éi»ÉÖA·òR úªÍt[É¨¢ÄãÉéîñð¾é±ÆC»µÄòi¨¿jªç©¶ßí©ÁÄ¢éêÉÍ CT ÌÝ©ç¨±È¤jóªÍÌ½ßÌîñð¾é±ÆÅÁ½10) Bz¨Ì 3 ³ªzª¾çêé¾¯ÅÈ­C¨¨æ»Ì»À±ÍCSPring­8 Ìr[C BL47XU É¨¢ÄCwg¬ðmé±ÆàÅ«éÆ¢¤ÉßÄLøÈàÌÅ

é^zû X ü CT @ðp¢Ä¨±ÈÁ½B±êÉæèC

ªCÁèÌ³fÌzû[ðp·é½ßÉTvTCYñ50 mm æè¬³È¿ÅÍñ200 nmC»êæèå«¢éBú³CxCðàÂ¨ÌÌ X üÌ§ß¦C¿ÅÍñ500 nm ÌÀøIÈóÔªð\ðàÂ 3 ³É§ÀªtCÍ LAC lCm ÆÌÖWÉéB

CT  ª ¾ ç ê ½ B 3 Í Å q × ½ analytical dual­energy
microtomography ÉæèCèÊIÈz¨Ì 3 ³ªzi3úËõ Nov. 2012 Vol.25 No.6  331

Fig. 5

(Color online) A nal cross section of an Itokawa particle(RA_QD02_
SEM0031) (from SOM in10)). (A) An FE_
back­scattered electron image. The particle is embedded in aresin. (B) A CT images corresponding to the FE_SEM sec­tion shown in (A). (C) A CT image of a vertical section of(B) after the left part was removed by polishing. (D) A CT
image of a horizontal section of (B) after the upper part wasremoved by polishing. Abbreviations for minerals are thesame as Table 1.

Fig. 6(Color online) Modal compositions of minerals of Itokawa
6, L4_6 and H4_particles10) and ordinary chondrites (LL4_623)).

Fig. 7

Slice images of Itokawa particles obtained by
microtomography (from10)). (A) A polymineralic particle
with thermally equilibrated texture (RA_QD02_
0063: 7 keV,
X431 cm|1). (B) A monomineralic particle with thermal­
ly equilibrated texture (RA_QD02_0014: 7 keV, X287
cm|1). Some voids dene a 3D plane (arrows). (C) A parti­
cle with rounded edges on the surface (RA_QD02_0042: 7
keV, X575 cm|1). (D) A particle with thermally less­equilibrated texture (RA_QD02_0048: 7 keV, X431
cm|1). Mes: mesostasis. Abbreviations for minerals are thesame as Table 1.

³gDjð¾é¾¯ÅÈ­CãÉ¨±Èíê½jóªÍÌ½ßÉÇÌæ¤ÉTvðØf·é©Æ¢¤f[^ðÁ½B±qÌ 9 öxÍMÏ¬ðó¯½

ñµC÷×È±q©çÅåÀÌîñðø¦æ­¾é±Æ

Æà®IÅ

ªÅ«½iFig. 5jB±Ìæ¤ÉC}CN CT ðp¢½ªgDðà¿iFigs. 7ABCjCLL5ÍÍÍâÔ³TvúªÍÌî{íªÅ

àÌÅ

Á½B

é¢Í LL6 ÉÎ·éÁ½BêûC1 öxÌ±qÍMÏ¬ÌöxÌá

^[TvÌªÍÆµÄÍCNASA ÌX^[_Xg¢ LL4 ÉÎ·éÆl¦çêégDðàÁÄ¢½iFig.

væÉæè¿Açê½a¯oTvÉÂ¢ÄäXÌO

7DjB

[vÉæÁÄnßÄ CT ªp³ê20,21)CÍâÔ³T

e±qÌ 3 ³O`©çC±qTCYC3 ³`óâ\v  Å analytical dual­energy tomography ð p ¢ ½ n Ê\¢ðßCSXâÕËjóÀ±Ê24) ÆärIÈªÍª¨±ÈíêC¬÷ðûß½àÌÅµ½10) BCgJ±qÌÝÏTCYªziFig. 8jÍùzéB

CT Beð¨±ÈÁ½48±qÌÌÏÌaÍ4.2~106mm3 Å

è ¼ a ñ 100 mm ÌÉ   · é i ¿ Ê Í 15

ñ_2 ÌÎªzðà¿CSXiùzÍñ_3jÆÍÙ Èè mm T CY ÈºÌ ±q ª­ È¢± Æð ¦µÄ ¢mg)22)B±êçÌ±qSÌÌz¨[hg¬ÍÊRhéB±êÍCVÌÌdÍÌá¢ð½fµÄ¢éàÌÆl¦CgÌÅà LL RhCgÌàÌ23)ÆÅàæ­êv

çêéªCÚµ¢´öÌÁèÉÍÁÄ¢È¢B3 ³`µ½10)iFig. 6jBÜ½C±êÉæèßçê½oN§xóªzi3 ²äÌªzjÍÕËÀ±jÐÌªzÆæÊÅ«Í3.4 g/cm3 Å¸iFig. 9jCCgJ±qÍÕËjÐÅèCupCf1) i2 ÍQÆj332  úËõ Nov. 2012 Vol.25 No.6

éÆl¦Äæ¢ðà ¡ ¬f¯CgJ©çÌ¿ÌúËõgOtB[ðpµ½ªÍFig. 8(Color online) Cumulative size distribution of Itokawa par­ticles (from10)). Sphere­equivalent diameters of the tapping
samples and the diameter of the spatula samples are shown.
The slope of the spatula sample should become steeper dur­ing sweeping by the spatula, which would have pulverizedsome of the particles.

Fig. 10(Color online) The 3D external shapes of Itokawa particles(stereograms). (A) A particle with sharp edges (RA_QD02_0023, box size: 232~232~203 mm). (B) A particle withrounded edges (RA_QD02_
0042, box size: 112~112~93mm).

J±qÅÍFßçêÈ©Á½ªC±êÍÕË¬xÌá¢ÉæéàÌÆl¦çêéB

5. ÍâÔ³TvúªÍÌÜÆßÆ
¡ãÌW]êAÌúªÍÉæèCS ^¬f¯ÍF»ðó¯½ÊRhCgÅéÆ¢¤±êÜÅÉè³êÄ¢½¦ÎÆ¬f¯ÆÌÎÖWª³µ©Á½±ÆªÅIIÉm
Ø³êC¦ÎÌN¹ÉI~ªÅ½ê½¾¯ÅÈ­CF»ðÍ¶ßÆ·é¬f¯\ÊãÅÌlXÈvZXª¾
ç©É³ê½iFig. 2jBµ©µÈªçCCgJ±qÌâFig. 9(Color online) 3D shape distribution of Itokawa particles
and fragments of impact experiments (from10)). The lon­gest, middle and shortest axes, a, b and c, of the Itokawa
particles were obtained by ovoid approximation of the CTdata.

Î¶¬NãâåKÍÕËNãiCgJÌ`¬NãÉÎ·éÍ¸ÅéjÍí©ÁÄ¢È¢BÜ½C¾zÉFüÆËâ÷¦ÎÕËÆ±q\ÊÅÌñ»¿»ÉSim±q¶¬â@BIÕÆ¢Á½¬f¯\ÊvZXÌIÈðÍ±ê©çÌÛèÅ

èCSXÆÌär¤ÉæèàÜß½åCÌÈ¢VÌÅÌ\ÊvZXÌïI±Æð¦µÄ¢éBÀÛC½­Ì±qÍjóÅÅ«½ÆlÈðª¡ãúÒ³êéB¦çêéV[vÈGbWðàÁÄ¢½ªCêÌ±q\

Yf¿¨¿âL@¨Ì¶ÝÍ»ÝÌÆ±ëmF³êÄ¢ÊÉÍÛÝðÑÑ½GbWªÏ@Å«CÕËjÐªÕ³

È¢7,8) B10 mm ÈºÌ±qÍ»ÝÌÆ±ëÀSÉnhê½Æl¦çêéiFigs. 7BC, 10jB±êÍCCgJÖÌOÅ«È¢½ßC¢¾ªÍÌ½ßÉzª³êÄ¢È¢÷¬VÌÕËÉNöµ½nkgU®ÉæèUN³ê½±qªC±êçÌÉÍCgJÉ~è¢¾L@¨àÜß½^®ª¨±èC±qª@BIÉÕ³ê½àÌÅÙ¿¨¿Ì¶ÝªúÒ³êéBéÂ\«ª¢B±Ìæ¤È@BIÕªCF»5)â¾z
óKXÌÅ¿Ý6)ÆÇÌæ¤ÈÖWÉ¤ÛèÅéÌ©Í¡ãÌ

éªC±êçð·éÆC¿ÊÌ¬³ÈV

Ì\ÊÉ¨¢Äà®IÈvZXªärIZ¢^CX

6. ÍâÔ³ 2 væÍâÔ³ 2 ÍCÍâÔ³Ìwe[Wðó¯p¢¾P[Å¨±ÁÄ¢é±Æªí©Á½iFig. 2jBêûCú¬f¯T¸ÉTv^[væÅÌSXÅÝçêéæ¤ÈCSX±qÌZðÍCg

¿ã°C1999JU3 ÆÄÎêé¬f¯iñ900 mjðÏªµC

éB2014NÅ

úËõ Nov. 2012 Vol.25 No.6  333

TvðÌæµÄC2020N12ÉnAÒª\è³êÄ¢éB»Ì½ËXyNgiC ^jæèCYf¿RhCg¦ÎÉÎ·é¨¿Ì¶Ýª\z³êÄ¢éB±Ì¦ÎÍz¨ÉiÜz¨ÆµÄz¨ÉÜÜêéjÉL

12)
13)
14)

ÉCmÉ¶½Ì´

15)Þ¿ÉÎµÄ¢éBTvªÍÉæèC±êçÌ¨¿

16)
17)

@¨©çÈéàÌÅC»ê¼êÅÌnÌ¾znúÉ¨¯éi»Ìð¾ªúÒ³êéBñ10N
ãÌªÍÌ½ßÉCóÔªð\»â X üñÜðpµ½gOtB[ÈÇC³çÈéúËõ}CNgO
tB[ÌJ­ªdvÅéBÓ«CT Tu`[ðÍ¶ßÆ·éÍâÔ³TvúªÍ`[ÌF³ñCÜ½ JAXA L

[V`[ð

18)
19)
20)
21)
22)
23)

Í¶ßÆ·éÍâÔ³TCGXvWFNg`[ÌF³ñÉ´ÓµÜ·BÜ½CÍâÔ³Tv±qÌ}CN24)

E. Nakamura et al.: Proc. Nat. Acad. Sci. 109: E624_
E629(2012).
L. A. Taylor et al.: J. Geophys. Res. Planets 106, 985 (2001).
U. Bonse and F. Busch: Progr. Biophys. Mol. Bio. 65, 133(1996).
A. Takeuchi, K. Uesugi and Y. Suzuki: J. Phys.: Conf. Ser.
186, 012020 (2009).
A. Tsuchiyama et al.: Am. Min. 90, 132 (2005).
S. Ikeda, T. Nakano and Y. Nakashima: Mineral. Mag. 64,
945 (2000).
A. Tsuchiyama et al.: submitted to Geochim. Cosmochim.
Acta.
K. Lodders: Astrophys. J. 591, 1220 (2003).
A. Tsuchiyama et al.: Meteor. & Planet. Sci. 44, 1203 (2009).
T. Nakamura et al.: Science 321: 1664 (2008).
A. Tsuchiyama et al.: Lunar Planet. Sci. Conf., XLII, 1870
(2012).
R. Hutchison: Meteorites: A Petrologic, Chemical and Isotopic
Synthesis. 506 pp. Cambridge Univ. Press, Cambridge(2004).
F. Capaccioni et al.: Nature 308, 832 (1984).

 CT Beð¨±È¤±ÆªÅ«½ SPring­8 ÉÓÓð\
µÜ·B

ÒÐî
Ql¶£

1)
2)
3)
4)
5)
6)
7)
8)
9)
10)
11)

A. Fujiwara et al.: Science 312, 1330 (2006).
M. Abe et al.: Science 312, 1334 (2006).
H. Yano et al.: Science 312, 1350 (2006).
T. Nakamura et al.: Science 333, 1113 (2011).
T. Noguchi et al.: Science 333, 1121 (2011).
K. Nagao et al.: Science 333, 1128 (2011).
H. Naraoka et al.: Geochem. J. 46, 61 (2012).
F. Kitajima et al.: Lunar Planet. Sci., XLII 1855 (2011).
M. Ebihara et al.: Science 333, 1119 (2011).
A. Tsuchiyama, et al.: Science 333, 1125 (2011).
H. Yurimoto et al.: Science 333, 1116 (2011).

334  úËõ Nov. 2012 Vol.25 No.6

{R¾

såwåw@w¤Èn f¯Èwê
UÉ³ö
E­mail: atsuchikueps.kyoto­u.ac.jp
êåFz¨wÉf¯¨¿Èwmªðn
1982Nåww¤Èn¿wêåÛömÛöC¹CwmCNASA W
\FZ^[¨æÑISåwÌ¤õCsåwwèCåãåw³{utÉ³öC¯åwwCw¤
È³öÉ³öðoÄC{Nxæè»EBðà ¡ ¬f¯CgJ©çÌ¿ÌúËõgOtB[ðpµ½ªÍAnalysis of samples collected from theAsteroid Itokawa using synchrotron
radiation based tomography
Akira TSUCHIYAMA
Abstract

Division of Earth and Planetary Sciences, Graduate School of Science, Kyoto
University, Kitashirakawaoiwakecho, Sakyo­ku, Kyoto 606_8502, Japan

Preliminary examination of small particles collected from asteroid Itokawa by the Hayabusa
spacecraft was successfully made in 2011. The examination denitely conrmed that the surface
material on an S­type asteroid is composed of ordinary chondrites suered by space weatheringand led to the end of the origin of meteorites. The examination also revealed a variety of processeson the asteroid. Our research group examined three­dimensional structures of the Itokawa parti­
cles with sub­micron resolution using synchrotron radiation­based microtomography at SPring­8.
3D distribution of minerals of each particle was obtained by comparing a set of CT images taken atdual x­ray energies below and above the K­absorption edge of Fe (analytical dual­energy micro­
tomography). Our results show that the Itokawa particles correspond to ordinary chondrites (LLchondrites). 3D external shapes of the particles showed that the particles are impact fragments
and some of them were abraded. Use of microtomography for non­destructive analysis can pro­vide key information for the design of later destructive analyses of the same particle by providing
critical information concerning where a particle should be cut to obtain the best areas of specicminerals in cross sections of these small particles. This is one of the key features of the Hayabusa
preliminary examination strategy for the analytical ow sequential studies.

úËõ Nov. 2012 Vol.25 No.6  335