The new external microbeam facility of the Oxford nuclear microprobe and its application to problems in archaeological science

436 I!; ' I ' : i| i ' k /^aUPTMANM ^9] Keesmann. I.. 1989, Chemischc und m • - a ion eisen eiche Schiacken. In R p. nciailun c sucluiniien zu 1987. Symposium Lihlice Í9H7. P aguc o i O'^' Í20] C addock,PT., 1995.£ í / /V/í «/A/,»,,,„ , 1211 ^i i n I - * " l* n(im i(>n. uJinhu uh '■''i Gale, N.H., Papas ama aki. A.. S os-Gale y . " ce- and Coppe Me allu gy in he Acgean B o— ^ CoppC w An iqui y, ed. PT. C addock and ""<1 Snwl in i Technology 81-101. ^22] Le y, T., Adams, R.A. and Na|j „ Hughcs). B i . .Musi:um C)cc. ' Jo dán: The Jaba! Ham a Fidan (^k dí!Tu Homepage. A duu-nlo^y P ojcc. 1999. In e ne - Kólschbach,S., 1999. Expc imcnic zu .Simni. . . . . ■y.i.- Ve ah ens echnik on Windd cn. P iili'sK. ische Kup c gcwinnung. Wissenscha en, Rhcin.-Wes al. T-cchn M ""u «-''"ghau. Hii enwesen und [241 D , "• ^'<» hschulc Aachcn. ' oachmann, H.G. and Ro hcnbc g. B.. 19x0 In ^ i/cesFup e /,n77nwa- a/. (cds.H.G Con on S- e he J, Bochum, 215-236. ^ Rolhcnbc g). Dc Anschni . Be»- Haup mann, A., Lu z, J., Pe nicka. £. yp.i . 1 • , , -y de iihes en Kup e e hü ung im Vo dc cn O icn ' í'"u ii Teclinolog» Moun ains-A chaeologica Ana olica e M " ""iTn e ! ciío o . , / I '-^''poia nica Alba Painiicn Dedica a Uni e Si a La Sapienza, Rom, ícd. M. F angipane H w. 4 1 ;, ' au - « M. Mellink^ 541-572. Haup mann, M. I.i^c an , P. Mn lhiae & New ¡=™ ' A . B^'^h-nann H.G, nd Maddin. R,. |yy„, c halcl. hic Cppe Sme ing; AM ?T h . A chnc.mci y (ej s. Demi ci. Oze and G.D. Summc .s),Tubi ak. Anka a 3 jo Haup'^nn.A.andRoden.C.. '''««■ A cha«mciailu g¡sche Un c suchungcn zu Kup c - N.H., Bachmann, HG.. Rchenbe g. B., S ns-Cú lc. Z.A. and Tylcc e R F.. 1990, ne Ad en i iou.s P oduclion o I on in ihc .Smeliing al Coppc . In Resmn hes in 'hn ^abah 1959.1984. V„l. II.-The Aneen, Me,.,lu„.^, „, c- In.,-,. A,-cl,.,eo-McU,ll■ S'"' (ed. B. Ro henbe g), London, 182-191 . Roilie ibe g, B. and Shaw, C.T., 1990. The Disco e y <, a Oippo Mine and Sme"®'' m Ihe End o Ihe Ea ly B onze Age (EB IV) in he Timna Vallcy. In.s . A chaeo-Me- • S udies, Newsle e 15/16, 1-8. ^^"P mann. A., 1989, The Ea lie.s Pe iod.s o Coppe Me.allu gy in Feinan/Jo dan. I" « ^o ld A chaeome allu gy, íed: A. Haup mann. E Pe nicka and G.A. Waene ). C>e ^nschn¡ ,Beihe 7 .Bochum, 119-135. [27] [28] [29] [30] [3l] p. VCU.y, I7/0, -y [32j Is ael Explo . Soc., Je u.salem. ®=''-A ieh, I., 1983, Cenl al-Sou hem Sinai in he Ea ly B onze Age II and ,,, Reía ^"■ an, R. (ed,), 1978, Ea y A ad: The Chalc„u,hu Seniemen, and Ea ly B onze Age ^"y- Is ael Explo . Soc., Je usalem. ^'•-A ieh, I., 1983, Cenl al-Sou hem Sin 'dnship wi h Pales ino. Le an! XV, .39-48. THE NEW EXTERNAL MICROBEAM FACILITY OF THE OXFORD NUCLEAR MICROPROBE AND ITS APPLICATION TO PROBLEMS IN ARCHAEOLOGICAL SCIENCE G.W. G ime*'^ Abs ac Recen de elopmen s o he ex emal beam acili y o he Ox o d Nuclea Mi- c op obe ha e led o an enhancemen o he capabili ies o he ins umen o analysing la ge o sensi i e objec s in ai wi h a spa ial esolu ion o 50 o 100 (xm. Used in conjunc ion wi h he 1 pm esolu ion in- acuo acili y his p o ides a unique elemen al analysis acili y which is being applied o a numbe o a - chaeological p oblems. This pape desc ibes b ie ly he capabili ies o he aci li y and ou lines he ange o applica ions. 1. INTRODUCTION Ion Beam Analysis (IBA) has a well-es ablished ole in he cha ac e isa ion o a - chaeological and his o ical objec s. The combina ion o ace elemen sensi i i y and quan i a i e accu acy o e ed by he echniques o P o on Induced X- ay Emission (PIXE) o Ru he o d Backsca e ing (RBS) p esen s a solu ion o many p oblems in- ol ing he s udy o a e ac s and aw ma e ials. Using a sui able mic o- ocusing sys- em, IBA can be ca ied ou wi h a spa ial esolu ion o he o de o 1 pm [1], bu his is o en inapp op ia e o a chaeological objec s. This is due o he na u e o he ma e ials, which a e o en he e ogeneous, con aining pa icula e inclusions wi h diame e s o less han 100 mic ome es. The long pene a ion dep h o MeV ligh ions a e ages he signal o e he ange o he ions ( ens o mic ome es) and so unless hin samples a e used, i is no possible o analyse small inclusions sepa a ely om he ma ix and he ad an age o using mic on o sub-mic on beams is los . Ano he p ac ical disad- an age o high esolu ion mic obeam acili ies o a chaeological applica ions is he equi emen o place he sample in an e acua ed chambe , which o mos a chaeo- Uni e si y o Ox o d. Depa lmen o Ma e ials. Pa ks Road. Ox o d. OXl 3PH. UK 438 íi i ilü 11 ! '<. 1^1 N G.W. logical o his o ical objec s equi es sampling, which may be highiy undesi able o p ecious, delica e objec s. 2. THE OXFORD EXTERNAD MICROBEAM FACILITY The long ange o MeV ions in ai p esen s he possibili y o analysing la ge o agüe objec s in ai wi h no sampling equi ed. The beam diame e is deg aded by collisions wi h ai molecule (by app oxima ely 10 pm pe mm o ai pa h), bu as dis- cussed abo e, his is no a majo p oblem o a chaeological samples and by ca e ul design, a spa iai esolu ion o less han 50 pm can be achie ed. Fo he majo i y o sample ion beam analysis in ai is non-des uc i e; he p esence o ai o helium a ound he sample dispe ses any localised hea ing cause by he beam, and so p e en s any he mal damage. In o ganic ma e ials, decomposi ion o la ge o ganic molecules can III Cong eso Nacional de A queome ía 439 x- ay de ec o (ligh elemen s) Beamiine (High acuum) Pa ióle de ec o (below) Magne ic de lec o ;^^Sample Exi nozzle Gamma ay de ec o abso be x- a/de ec o ( ace eie/wdd sj j . ihe V ^^hema ic plan iew o he ex e nal beam analysis acüi y al Ox o d. The beam eme ges o n Q "^o he beamiine h ough a 300 pm diame e hale in a 2mm diame e coppe nozzle sealed Q ^ . ^ hm) plás ic oil. X- ays emi ed om he sample a e de ec ed by wo de ec o s moun ed aí ay /• ^he beam. One de ec o is i ed wi h an x- ay ab.so be o kiü he in ense low ene gy has ensu e good de ec ion limi s o he ace elemen s while he o he de ec o he °^^ ) be and is i ed wi h a magne ic de lec o o ensu e ha high ene gy p o ons do no each o de ec o o gamma ays is moun ed a 90" o he beam. Below he beamiine. a de ec o ple'^^^^'^' S p o ons eco ds he RBS spec um and allows he o al amoun o cha ge alling on he sa n- ^^m o ed. No shown in his diag am a e a ideo mic oscope which uses a mi a o iew he samni"'!'"^^ o/ e sample du ing analysis and a low powe alignmen láse o a.ssis in po.si ioning he ^ o analysis. Figu e 2. A gene al iew o he new ex e nal beam acili y being used o he cha ac e isa ion o su ace laye s on an IB"" cen u y b ome s a ue o Bud- dha. cause discolo a ion, bu in many cases (e.g. pape s) his ades o e a pe iod o days and in any case is con íned o he small a ea o he beam. An ex e nal beam sys em has been de eloped o he Ox o d Scanning P o on Mic o- p obe acili y using design concep s desc ibed i s by he AGLAE g oup in Pa ís [2] (see i gu es 1 and 2). The key o high pe o mance o his ype o sys em is o mini- mise he dis ance be ween he exi o he beam om he acuum and he sample. This educes beam sca e ing and also educes he abso p ion o he emi ed signáis, bu in o de o allow a ee pa h om he sampling poin o he de ec o . In his design he exi nozzle consis s o a hollow coppe cylinde wi h he diame e educing in s eps om 12 mm o app oxima ely 2 mm. Coppe was chosen o he nozzle ma e ial in o de o educe he gamma ay backg ound which migh esul i ligh elemen s such as Al we e used and he beam s ikes he inne su ace. The only signáis induced om coppe a e he Cu x- ays, which do no escape om he walls o he nozzle. The beam eme ges in o ai h ough a 300 (jim diame e ape u e co e ed wi h an 8 (jim Kap on 440 (y y. GRME III CoNGRi-so Nacional db A queomb ía 441 $ ,. | lli i ■ 'i : í' i I : 1 , Figu e 3. View h ough he ideo " ic oscope o he ex e na! beam ocili y, This shows he coppe exi ozzle p ojec ing om he bo om he image and he ^ i ace o a sampie o J 8"" cen u y islamic lus ewa e. Fhe ou line o he lus e giazed deco a ion can be seen as he da k egions o he sampie. ^indow. Two quad upole lenses ocus he beam h ough he no/.zlc, so ha he amoun beam s iking he ape u e is minimised. No e ha his aiso means ha he spa ial '"esolu ion is no de e mined by he size o he ape u e holc. The sampie is moun ed 3pp oxima ely 4 mm om he window, allowing a csolu ion o 40-50 pm o be ^chie ed on he sampie. De ec o s o x- ays, ecoiling p o ons and gamma ays allow ®"3lysis using PIXE, RBS and also P o on índuced Gamma- ay Emission (PIGE) analy- o he de ec ion o ligh elemen s such as Li and F. This allows i ually he en- Pe iodic abie o be co e ed in a single measu emen . A ideo mic oscope and a Powe láse a e used o align he desi ed egión o he sampie in he beam (sea gu e 3). pyjj echnical de ails o he new ex emal beamiinc will be p esen ad alsa- whe e [3]. ^ sepa a a de elopmen , he ex e nal beam acili y has been i ed wi h a high ^®^^sed pulsad láse o enable he su ace o he sampie o be abla ad a axac ly spe ^Po as he analysis is aking place (4). This exci ing de elopmen is aimed em^' co osión laye s on ancien me áis, bu he abili y o dia ^"^3ce ilms in a well con olled manne o e an a ea o less han 100 pm ha e implica ions o many aspec o he analysis o ancien ma e ials, ^ desi able o cha ac e ise sepa a ely bo h he co osión ilm o pa ina and •^nde lying bulk ma e ial. 3. ^PPLICATIONS OF THE OXFORD EXTERNAL BEAM FACILITY The e iai/- applica ions o he Ox o d ex e nal beam o a chaeological ma- summa ised below: Panel ( un) Hg% Top 5,08 11,30 Top 5,08 11,60 Cen e 5,06 15,00 Bo om 6,16 14,50 Mean 5,35 13,10 s.d. 0,54 1,92 3.1. CORROSION FILMS, SURFACE LAYERS AND BULK COMPOSITION OF METALS In addi ion o using PIXE o cha ac e ise he composi ion o bulk me áis, hin (< 10 pm) su ace laye s can be cha ac e- i sed accu a ely and non-des uc i ely using RBS. This p o ides in o ma ion comple- men a y o ha which can be ob ained o hick laye s using he láse abla ion acil i y. The Ox o d ex emal beam has been used o in es íga e a wide ange o me al ypes, and alloys based on coppe , sil e , gold and i on ha e been in es iga ed. In a s udy o a medie al al a c oss [3], he hickness and composi ion o he gilding laye s was de e mined om he ela i e in ensi ies o he gold, me cu y and coppe x- ays induced by he beam. The a io o he gold and me cu y L-lines p o ided he Au:Hg a io in he amalgam gilded i lm, and since he coppe x- ays om he subs a e a e abso bed by he o e lying gilding laye , he a io o he coppe K-line o he gold L-line p o ides a e y accu a e measu emen o he hickness o he i lm, as shown in able 1, in which p esen s he hickness and pe cen age o me cu y eco ded on he h ee back panels. Ano he example, shown in i gu e 2, in ol ed he in es iga ion o a I?"* cen u y Buddha om Thailand. Al hough his objec was b onze, he black su ace had an un- usual appea ance. Using RBS, i was possible o de e mine ha he su ace was coa ed wi h a hin laye o o ganic ma e ial ich in ca bón and oxygen which was di using in o he coppe . One explana ion o his could be he in e ac ion o he me al wi h he smoke o de o ional lamps and candles o e a long pe iod. 3.2. POTTERV AND GLAZES A majo ad an age o he ex emal beam acili y in he s udy o po e y is he abili y o analyse he whole objec wi hou sampling, which can be di icul and undesi ed on a e agile objec s. A ange o analyses ha e been ca ied ou bo h on whole ob- jec s (e.g. he cha ac e isa ion o blue and whi e glazes on Chínese po celain) and on agmen s (e.g. he analysis o IS"* cen u y Islamic lus e glazes). In he case o he lus e glazes, he composi ion o he me al su ace laye can be de e mined using PIXE and he hickness o he me al laye can also be de e mined using RBS. Figu e 3 shows he su ace o a lus e giazed she d iewed h ough he ideo mic oscope o he ex emal beam acili y. The coppe beam exi nozzle can be seen a he bo om o he pic u e and he deco a ion o he sampie can be seen. The da k egions a e lus e giazed. Figu e 4(a) shows he RBS spec mm acqui ed om he lus e giazed egión using a p ima y beam ene gy o 3 MeV. The small high ene gy peak in he spec mm indica es he me al lie coppe laye esul ing om he lus e glaze. The o al a ea o his peak is a measu e o he amoun o coppe p esen in he ilm, while he shape gi es an in- dica ion o he dep h dis ibu ion. In his case, al hough he s a is ics we e no con- 442 Q.W. G iue III Cong eso Nacional de A queome ía 443 ÍH5 195 205 2i5 225 2^^ 2-3** 2^^ 275 Kca.ojÍ ^MeV " ins ewa e ^lazc e n dcd in ai nm/ií; p o on.s i /¡ an iniíUil en^^'Sy iiXC l TÍ/ Z*^/ I í* (*/ y I li u y/ í* y/y 1 yi»9y/ (/«•■• /■'>•.. «7... *í/ / S'/ //// i Iíi ¡ í/// //V / // ? ^ ^ 'neasu ed da a is shown as do s and hc hin ¡hu- is a hc( e ín p o iig , "'"•^" ea aai ^nd he appeu s as he snudl peak in hc hii h ene s^' e pión o he un¡ ig J O om he glaze appea as s eps a lowe ene py. The ¡a pe peak in he cen e o a bg ecoils om ni open and nxypen nuelei in he ai . The dala n /. eeo ded in 90 ^Pec ^ o JOOpA. (h): The iheo e iea! sample dep h dis ihu ion used o ealeida e he "^ igu e 4 (a). ^lus easibili y s udy, he e is a s ong indica ion o a di usion p o ile in he glaze, as shown by he simuia ed cu es, esul ing in he p o ile shown "gu e 4(b). he 3.3. *3lass and enamel beajp ^ conside a ions o sampling aiso appiy o glass objec s and he ex e nal h3s also been applied o he cha ac e isa ion no only o ancien jec jy í^ ge agmen s bu also minia u e mediae al enamelled panels. Thc ob- such analyses has la gely been o de e mine he na u e o added cons i uen s ^olo an s. Jewp,. ■^LLERY and gems ones Th P o epa^ inc easing in e es in he analysis o ancien gems ones as an aid s udies [5 and 6]. Many gems one mine als do no ha e a ixed comp^si- ion, and may comp ise a mix u e o end-membe s in a ying concen a ions. Exam- ples o hese include game s which ha e h ee end membe s and ou malines wi h as many as wel e. De e mining he end-membe ac ion allows he compa ison o s ones (e.g. o de e mine whe he all s ones in an objec we e om he same sou ce), while he ace elemen con en may be cha ac e is ic o he mine al deposi , al hough he e is s ill a only a limi ed amoun o compa ison da a a ailable o his ype o applica- ion. The ex emal beam acili y is ideal o he cha ac e isa ion o moun ed gems ones, since hey do no ha e o be emo ed om he objec in which hey a e moun ed and he echnique is non-des uc i e. The Ox o d acili y has been used in a numbe o easibili y s udies, including he cha ac e isa ion o he í s ime o he ou maline in- aglio o Alexande he G ea om he Ashmolean Museum [7]. 4. CONCLUSION AND ACKNOWLEDGEMENTS This b ie desc ip ion o he Ox o d ex emal beam acili y has demons a ed he ca- pabili ies o in-ai mic o-analysis using ocused beams o MeV ions. This echnique o - e s unique ad an ages o he a chaeological scien is o he cha ac e isa ion o ancien ma e ials and a e ac s, and a b ie summa y o applica ions has been p esen ed. This wo k has na u ally in ol ed he collabo a ion o co-wo ke s om many di e en ins i u- ions, and he au ho especially wishes o acknowledge he con ibu ions o he ollow- ing people: Ms M.H. Ab aham and D J.P No ho e o he Uni e si y o Ox o d Depa - men o Ma e ials, D R. Cambe o So heby's, London, D M. Vicke s o he Ashmolean Museum, Ox o d, P o . M. Ti e o he Resea ch Labo a o y o A chaeology and he His o y o A , Ox o d and D L. Tho eson o he Ge y Museum, Los Angeles. 5. REFERENCES [11 G ime, G.W., Dawson, M., Ma sh, M., McA hu , I.C. and Wa , F., 1991, The Ox o d sub-mic on nuclea mic oscopy acili y. Nucí. Ins . and Me hs. B54, 52-63. [2] Calliga o, T, Maca hu , J.D., and Salomen, J., 1996, An imp o ed expe imen al se up o he simul aneous PIXE analysis o hea y-elemen s and ligh -elemen s wi h a 3 MeV p o on ex emal-beam. Nucí. Ins . and Me hs. B109, 125-128. [3] G ime, G.W., Ab aham, M.H., and No ho e , J.P., The new ex emal mic obeam o he Ox o d Nuclea Mic oscopy acili y, o be p esen ed a he 7"' In ema ional Con e ence on Nuclea Mic obeam Technology and Applica ions, Bo deaux, Sep embe 2000, and published in Nucí. Ins . and Me hs B, 2001. [41 Ab aham, M.H., G ime, G.W., and No ho e , J.P., The combina ion o ex emal ion beam analysis wi h con olled láse abla ion o he s udy o hick co osión i lms on ancien me áis, o be p esen ed a he 7"' In ema ional Con e ence on Nuclea Mic obeam Tech nology and Applica ions, Bo deaux, Sep embe 2000, and published in Nucí. Ins . and Me hs B, 2001. [51 Que e, G., Bouquillon, A., Calliga o, T., Dubus, M., and Salomón, J., 1996, PIXE analy sis o jewels om an Achaemenid omb (4"'-cen u y-BC), Nucí. Ins . and Me hs. B109, 686-689. 444 G.W. Gk/aíe [6] Calliga o, T., Mossmann, A., Poi o , J.P., and Que é. G., 1998, P o enance s udy o u bíes om a Pa hian s a ue e by PIXE analysis. Nucí. Ins . ami Mah.s . B138, 846-850. [6] G ime, G.W., and Tho esen. L.. Ion Beam Analysis o Gems ones - In es iga ion o a Tou malíne In aglio o Alexande he G ea in he Ashmolcan Museum. in A chaeogeni- mology, (ed. L. Tho esen), Ge y Museum Publica ions. Los Angeles, (in p css). THE DEVELOPMENT OF SPANISH METALLURGY AND COPPER CIRCULATION IN PREHISTORIC SOUTHERN SPAIN Sophie S os-Gale'" 1. INTRODUCTION The e is no doub ha in he Spanish Coppe Age he ea lies echnological de e- lopmen s o coppe smel ing, and he ex ac ion o sil e and in, we e based on he mine al esou ces o he Ibe ian Península. Much wo k has been conduc ed ecen ly in Spain by scien is s ying o link he ace elemen al composi ion o p ehis o ic me al a e ac s wi h he known o e sou ces, in pa icula a la ge amoun o da a on coppe based me áis and sil e a e ac s om all dis ic s o Spain ha e been published e cen ly by Ro i a Llo ens [1]. Howe e , he a chaeome allu gical su ey o mine al e sou ces, ha needs o accompany such esea ch, is la gely limi ed o sou hem Spain, in pa icula he sou h wes [2]. In he eas em Medi e anean in he las wen y yea s he e we e se e al p ojec s combining a chaeome allu gical su eys and chemical and lead iso ope analyses o o es and B onze Age a e ac s [3 and 4]. The lead iso ope composi ions o o es and a e ac s a e used as hei cha ac e is ic ' mge p in s' [5], The analy ical me hod used cu - en ly o lead iso ope cha ac e isa ion o a chaeological ma e ials and o e mine als is The mal lonisa ion Mass Spec ome y (TIMS). This echnique p o ides highly accu- a e da a o lead iso ope (LI) composi ions o lead p esen in ancien me áis, glasses, glazes and pigmen s, e en i lead is p esen only a he le el o a ew pa s pe mil- lion [6]. The LI p o enance s udies a e based on he di e si y o p opo ions o lead iso ope a oms in o e mine als ela ed o hei geological his o y. This ea u e allows o cha ac e ise geog aphical sou ces o mine als acco ding o he pa em o he lead iso ope a ios measu ed in hem. The lead iso ope cha ac e is ics o o es do no change du ing hei smel ing, ca ying he LI inge p in o he o e in o he me al. The me hodology o lead iso ope p o enance esea ch is based on accumula ing iso opic, geochemical and a chaeome allu gical in o ma ion abou known o e deposi s ox Iso ace Labo a o y o he Resea ch Labo a o y o A chaeology. Uni e si y o Ox o d. Keble Rd. .^RH.