Determination of Photon Interaction Parameters of CaO and MgO for Multi-Energetic Photons using γ-ray Attenuation Technique

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1 IOSR Journal of Appld Physcs (IOSR-JAP) -ISS: Volu 8, Issu 2 Vr. I (Mar. - Apr. 26), PP Dtrnaton of Photon Intracton Paratrs of CaO and MgO for Mult-Enrgtc Photons usng γ-ray Attnuaton Tchnqu A.S. MadhusudhanRao, Hagos Tsgay 2, Abb Gtachow 3 Dpartnt of Physcs,HawassaUnvrsty,Hawassa, Ethopa, 2 Dpartnt of Physcs, HawassaUnvrsty,Hawassa, Ethopa, 3 Dpartnt of Physcs, HawassaUnvrsty,Hawassa, Ethopa. Abstract:Mass attnuaton coffcnts(µ ) ofcao and MgOat dffrnt γ-nrgs wr dtrnd xprntally usng narrow collatd ba transsson thod. Th saplwas rradatd wth radoactv pont sourc of dffrnt γ-nrgs vz. A (.595MV), Cs (.66MV), Co (.73MV &.332MV). Th transttd γ- photons wr dtctd and rcordd by a ai(ti) scntllaton dtctor wth rsoluton of 8.5% for.662mv of 37Cs. Thortcal ass attnuaton coffcnts wr statd usng xtur rul. Th xprntal s rportd n th prsnt work ar copard wth th calculatd s and th s obtand fro X-COM. Lnar attnuaton coffcnt (µl), total atoc cross-scton (σ t), lctronc cross-scton (σ ), ffctv atoc nubr (Z ff), lctron dnsty ( ff) and photon an fr-path (λ) wr dtrnd wth s-prcal rlatons usng ass attnuaton coffcnts obtand xprntally and thortcally. Exprntal s of paratrs rportd for CaO andmgo n th prsnt work usng dffrnt γ-nrgs ar copard wth th statd thortcal data. Kywords:Mass attnuaton coffcnt, lnar attnuaton coffcnt, ffctv atoc nubr, ffctv lctron dnsty. I. Introducton Th ntracton of hgh nrgy photons wth attr s portant n radaton dcn, bology, nuclar ngnrng and spac tchnology.th study of paratrs such as ass attnuaton coffcnt(µ ),lnar attnuaton coffcnt (µ l), total atoc cross-scton (σ t), lctronc cross-scton (σ ), ffctv atoc nubr (Z ff), lctron dnsty ( ff), an fr-path (λ)ar portant paratrs n undrstandng th physcal proprts of copost atrals. Thy ar vry portant n any appld flds lk nuclar dagnostcs, radaton protcton, nuclar dcn and radaton dostry.th quantts can b dtrnd thortcally and xprntally. Mass attnuaton coffcnt s a asurnt of how strongly a substanc absorbs or scattrs radaton at a gvn wavlngth, pr unt ass. Mass attnuaton coffcnt can b usdto drv any othr photon ntracton paratrs. Lnar attnuaton coffcnt (µ l) dscrbs th fracton of a ba of X-rays or γ- rays that s absorbd or scattrd pr unt thcknss of th absorbr. Thr hav bn xprntal and thortcal nvstgatons to dtrn (µ ) s n varous lnts and copounds/xturs. Hubbl [] rportd (µ ) s for 4 lnts and 45 xturs and copounds ovr th nrgy rang fro kv to 2MV. Ths tabls wr rplacd wth Hubbl and Sltzr tabulaton for all lnts (Z=-92) and 48 addtonal substancs of dostrcntrst [2]. Brgr and Hubbl dvlopd th thortcal tabls and coputr progra (XCOM) for calculatng attnuaton coffcnts for lnts, copounds and xturs for photon nrgs fro kv to GV [3]. Ths progra was transford to th Wndows platfor by Grward t al.[4] and th Wndows vrson s bng calld Wn-Xco. Scattrng and absorpton of X-ray and γ-radaton ar rlatd to th dnsty and atoc nubrs of an lnt. In copost atrals, t s rlatd to th ffctv atoc nubr (Z ff) and th lctron dnsty ( ff). In copost atral, a sngl nubr cannot rprsnt th atoc nubr unquly across th ntr nrgy rang, as th partal ntracton cross-scton hav dffrnt atoc nubr, Z, dpndnc [5]. Ths nubr s calld th ffctv atoc nubr, (Z ff), whch s vry usful paratr for any flds.effctv atoc nubr s a convnnt paratr for rprsntng th attnuaton of X-rays and γ-rays n a copost du and partcularly for th calculaton of dos n radaton thrapy [6]. Ths nubr s vry usful n choosng a substtut copost atral n plac of an lnt for a gvn nrgy dpndng on th rqurnt.svral nvstgators [7-9] hav ad xtnsv (Z ff) studs n varty of copost atrals such as bologcally portant atrals, sconductors, alloys, dostrc copounds and glasss. In ltratur, thr ar alost no rports on th study of photon ntracton paratrs of CaOand MgO. Ths proptd us to carry out ths work. Th xprntal s (of γ- ntracton paratrs wth attr)obtand for dffrnt γ-nrgs ar copard wth th statd thortcal data and th s of. DOI:.979/ Pag

2 II. Exprntal Mthod Transsson xprnt wth th narrow ba (good-gotry) stup has bn usd for asurng th ncdnt and transttd ntnsts, and hnc calculatng th attnuaton coffcnt.th gaa rays ar wll collatd usng lad collators. Each of th collators has a cylndrcal shap and a crcular aprtur. Th block dagra of th xprntal stup s shown n Fgur. Fg. Block dagra of th xprntal stup Th CaOof th prsnt study has hgh purts (99.5% 99.9%), conssts 7.5% of Ca and 28.5% of Oxygn.Th pllt s prpard by coprssng th CaO powdr at a prssur of 2 ps. Th wght of th powdr s 2. g and th thcknss of pllt s.4 c. Th MgO of th prsnt study has hgh purts (99.5% 99.9%), conssts 6.3% of Mg and 39.7% of Oxygn. Th pllt s prpard by coprssng th MgO powdr at a prssur of 24 ps. Th wght of th powdr s 22. g and th thcknss of pllt s.4 c. Th sapl atralhas bn shapd nto pllt wth a d st by usng hydraulc prss, for asurng th attnuaton. Th sapl was thn frly ountd on th sapl holdr. Th sapl holdr along wth th sapls fxd btwn th sourc and th dtctor at approprat poston nsurng a propr algnnt of sapl wth collaton 6 on thr sd. Th dstanc btwn γ- sourc and sapl was 8c and th dstanc btwn sapl and dtctor was 6c. Th sapl plltwas rradatd by dffrnt γ nrgs [(.595 MV), (.662 MV), (.73 MV &.332 MV)] ttd by C 24 A, 3 c 37 Cs and.73 µc 6 Co radoactv pont sourcs rspctvlyintnsts of th transttd photons wr rcordd,by choosng th countng t as 2 nuts, undr th photo paks. Th γ - ray counts of dffrnt nrgs wth sapl (I) and wthout sapl (I o) wr dtctd and rcordd usng a ai (Tl) scntllaton dtctor of (3 3nch) crystal coupld wth a ultchannl analyzr. Th gaa radaton dtctor usd n our study s a sodu odd thallu actvatd dtctor. Th dtctor has a rsoluton of 8.5% for.662mv of 37 Cs. Th.762 datr and.762 thck crystal s ntgrally coupld to a.762 datr photo ultplr tub (PMT). Th PMT has a 4 pn bas and can b ountd on two typs of PMT praplfr unts. Th on usd n our study s a coaxal n-ln pr-aplfr. Th wak dtctor puls ntrs th praplfr (or prap.) whch has two an functons; puls shapng and apltud gan, Th aplfd puls s thn fd to th Mult-Channl Analyzr (MCA), whch convrts th analog sgnal nto a dgtal nubr through an analog to dgtal convrtr (ADC), n ths cas th softwar s usd to control th MCA functons and othr sttngs, Th nrgy and th ffcncy of th syst wr calbratd usng a crtfd standard sourc fro th Intrnatonal Atoc Enrgy Agncy. Masurnt of γ-ray attnuaton counts at vry nrgy rpatd a nu of nn ts bfor and aftr th sapl was ntroducd and th avrag was consdrd n all our calculatons. Evry t th sourc of γ- radaton s rplacd by th othr n th sourc vault, th stup s rcalbratd. Th sa procdur s followd for ach sapl pllt. III. Thory Th rlatons usd n th prsnt work ar suarzd n ths scton. Mass attnuaton coffcnts for th dffrnt atrals and nrgs ar dtrnd by prforng transsson xprnts. Ths procss s dscrbd by th followng quaton: I I xp( t) DOI:.979/ Pag ()

3 Whr I and I ar un- attnuatd and attnuatd photon ntnsts µ = µ/ρ (c 2 /g) s th ass attnuaton coffcnt t (g/c 2 ) s sapl ass thcknss (th ass pr unt ara) Th total ass attnuaton coffcnt µ for any chcal copound or xtur of lnts s gvn by xtur rul [6]: w ( ) (2) Whr w s th wght fracton (µ ) s th ass attnuaton coffcnt of th lnt For a atral coposd of ult lnts th fracton by wght s gvn by n A w n A (3) Whr A s th atoc wght of th th lnt and n s th nubr of forula unts. Th total atoc cross-scton (σ t) for atrals can b obtand fro th asurd s of µ usng th followng rlaton Whr t A n A s atoc ass of atrals (5) A s th Avagadro s nubr. Total lctronc cross-scton (σ ) for th lnt s xprssd by th followng quaton ( ) A Z f t Z (6) Whr f dnots th fractonal abundanc of th lnt wth rspct to th nubr of atos such that f +f 2+f 3+f 4+..f = Z s th atoc nubr of th lnt Th total atoc cross-scton (σ t) and total lctronc cross-scton (σ ) ar rlatd to th ffctv atoc nubr (Z ff) of th atral through th followng rlaton Z ff t (7) Effctv lctron nubr or lctron dnsty ( ff) (nubr of lctrons pr unt ass) can b calculatd usng th followng rlaton: ff A Z ff n Th avrag dstanc btwn two succssv ntractons, calld th photon an fr path (λ), s gvn by x xp( x) dz xp( x) dx (9) Whr (µ l) s lnar attnuaton coffcnt and x s th absorbr thcknss. Th uncrtanty n th asurd physcal paratrs dpnds on uncrtanty n th furnac tpratur and asurnt of th ass attnuaton coffcnt, whch has bn statd fro rrors n ntnsts I,I and thcknss (l) usng th followng rlaton l ff (4) (8) DOI:.979/ Pag

4 ( I I I o l ) ln () l whrδi,, ΔI and Δl ar th rrors n th ntnsts I I I l I, I and thcknss l rspctvly. In ths xprnt, th ntnsts I and I hav bn rcordd for th sa t and undr th sa xprntal condtons. Estatd rror n ths asurnts was around 2%. Thortcal s for th ass attnuaton coffcnts can also b obtand by Wn progra [2]. Ths progra s basd on xtur rul to calculat th partal and total ass attnuaton coffcnts for all lnts and xturs at standard as wll as slctd nrgs. IV. Rsults And Dscusson Mass attnuaton coffcnts (µ )of CaO and MgOpllts studd n th prsnt work hav bn obtand xprntally for dffrnt photon nrgs. Th s obtand xprntally ar copard wth thortcal s calculatd by usng s-prcal rlatons (, 2 and 3)of scton-3 and wth th s of and ar found to b n good agrnt,as n th Tabls-2. It s clarly sn that ass attnuaton coffcnt dpnds on photon nrgy and chcal contnt. Th ass attnuaton coffcnt s dcras wth ncras n photon nrgy as sn fro Fgur.2. Th ass attnuaton coffcnt of a atral dcrass bcaus probablty of absorpton rducs wth ncrasng ncdnt photon nrgs whch rsults n th ncras n th transsson of photons through t. Th xprntal s for CaO and MgO studd n th prsnt work tnd to b slghtly sallr than thortcal s. Th total xprntal uncrtanty of ass attnuaton coffcnt s dpnd on th uncrtants of pak ara valuaton, ass thcknss asurnts, xprntal syst, countng statstcs, and ffcncy rrors and so on.th ass attnuaton coffcnt s dcras wth ncras n photon nrgy. Th ass attnuaton coffcnt s for lnts n th databas prtan to solatd nutral atos, and do not tak nto account olcular and sold-stat ffcts whch odfy th s, spcally n th vcnty of absorpton dgs. Also, databas dos not calculat nrgy absorpton coffcnts that rprsnt th convrson of photon nrgy to kntc nrgy of scondary Copton, photo and pard lctrons. Ths factors s to hav lttl ffct n th cas of CaO and MgO.Lnar attnuaton coffcnts (µ l), total photon ntracton cross-sctons (σ tand σ ), ffctv atoc nubr (Z ff), ffctv lctron nubr ( ff) and photon an fr path (λ) for CaO and MgO at dffrnt γ-nrgs ar statdby usng ass attnuaton coffcnts (xprntal, thortcal and s) obtand, wth th hlp of s-prcal rlatons (4-9) of scton-3 as sn fro Tabls-2.Although th dpndnc of and on th photon nrgy s donant at low nrgs, t s nglgbl at hgh nrgsthz ff and th ff rans constant and ar found to b ndpndnt of photon nrgy for a copound.th lctron dnsty s closly rlatd to th ffctv atoc nubr and hnc has th sa qualtatv nrgy dpndnc, as ffctv atoc nubras sn fro th Tabls-2 and fro Fgur 3 and Fgur 4,total photon cross-scton and lctron cross-scton (σ tand σ ) dcrass wth th ncras n photon nrgy. Lastly, th photon an fr path (λ) for a copound found to b ncrasng wth th photon nrgy as sn fro th Tabls -2 and Fgur 5. Ths s du to th dcras n th probablty of ntracton of photons n th atral wth th ncras n nrgy V. Conclusons Prsnt xprntal study has bn undrtakn to gt nforaton on th (µ ) and rlatd paratrs (σ t,σ, Z ff, ff and λ) for CaO and MgOat dffrnt γ-nrgs. W can undrstand that th (µ ) s usful and snstv physcal quantty to dtrn th (Z ff) and ( ff) of a copound. Th (µ ) s CaO and MgOn th prsnt study dcrass wth ncras n photon nrgy. Also, th varaton of (σ tand σ ) wth nrgy s dntcal to ass attnuaton coffcnt. Th data (µ, σ t, σ, Z ff, ff and λ) of Cao and MgO at dffrnt γ- nrgs n th prsnt study has bn rportd for th frst t. Acknowldgnts Authors thank Unvrsty Grants Cosson (UGC), w Dlh for th fnancal assstanc through Spcal Assstanc Progra (SAP) o. F.53/8/DRS/29 (SAP-). DOI:.979/ Pag

5 Tabl-µ,µl,σt,σ, Zff, ff. & λ s (coparson btwn xprntal, thortcal and X-co)of CaO at dffrnt γ-nrgs E [MV] A(.595) Cs(.662) Co(.73) Co(.332) Photon ntracton paratr X- Co Epr cal Eprc al µ [ -3 2 kg - ] µl [ - ] σt [ -25 barn/ato] σ [ -26 barn/ato] Zff ff [ 23 lctron/g] λ [ -2 ] Tabl-2 µ, µl, σt,σ, Zff, ff. & λ s (coparson btwn xprntal, thortcal and X-co) of MgO at dffrnt γ-nrgs E [MV] A(.595) Cs(.662) Co(.73) Co(.332) Photon ntracton paratr X- Co µ [ -3 2 kg - ] µl [ - ] σt [ -25 barn/ato] σ [ - 26 barn/ato] Zff ff [ 23 lctron/g] λ [ -2 ] DOI:.979/ Pag

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