Theory and Application of X-Ray and Gamma-Ray Backscatter to Landmine Detection

Abstract

Iloek 20) Cont'd) lFoir dfifferenit soorce/tietettor gt'onieiries are comipared ili terms of cotniitrate for ai givtii sour'e strength. agt*teti * trc-hei ratio, walsitivity to hevight variations above Ilici scattere'r, andt szitsitivitv to secgttvrer dvnsitN Thieoret'ical and prat tieal fmt Iors ill the' 54'ft'ttioli of souirces andit dv'i'ttors art' t'oisidt'enif Three' ttechiIit~iis for comp~ensating for height I'ariationis art' iisvwssvd, flth-most promising of whichl is a K-etfge-filter meiothod. ftatk~stat fir mine dletection is showni to be based on thec fact that t'xpfosivvs-have a lower *i~iramgt atomic mit'ndbr than thei surromndinig soil mntdiuni anid, therefore,.; lower photot'jt'trii' ahrstirptiozi crotss.%ec'tioti. As a ctonsequence. mlore' photton." arte hackseattert'd from c~~plwsivveý than fromt ,oil iii fthe eniergy region below about 200 keV. An account is given tIt flit-historY of rew~archi inl backscattt'r mine detfectioni spanning 5 years of' effort,. inelud. img ba~ici msitif'hi studiit's paranit'tt'r opt)?imizaition , comiputer simulationi, dvtvelopmeti'd of' c'tlipihunuit't. and fieldi te'stinig. It is ctwhielui thalit flthe limitations of thet backseiufer tipproaehi tiut1 weighl ifs tajiahtiitit's% hell viewved fromi ii practical militarv standtptint. Nevt'rtlt'less, flt' wo.(rk tltetrilt'dl dlid providet t'onisidlerable' in.,ighit infto thit mciii&'inisin of fthe photonbackseatfi'r process whtich may be of interest to tother re'searchers in flthe field. hf ,nft.t'hit'njstrv DI visitti, IL.233 I 1',kcrt'Ii tnunrt' La.boraiftor\ IP.i~inO. r' 114) 110 1 55