Nucl ear I nst rument s and Methods in Physi cs Resear ch A324 ( 1993) 191- 197 Nort h-Hol l and A spect r omet er f or 1 GeV el ect r ons usi ng sci nt i l l at i on det ect or s M . Anghi nol f i , P. Cor vi si er o, G . Cosci a, L . Mazzaschi , V. Mokeev, G . Ri cco, M . Ri pani , M . Tai ut i and A. Zucchi at t i I s t i t ut o Nazi onal e di Fi si ca Nucl ear e and Di part i ment o di Fi si ca vi a Dodecaneso 33, 16146 Genova, I t al y N . Bi anchi , E. De Sanct i s, P. Levi Sandr i , V . Lvcher i ni , V. Mvcci f or a, E. Pol l i and A.R. Reol on I s t i t ut o Nazi onal e di Fi si ca Nucl ear e Labor at or i Nazi onal i di Fr ascat i , I t al y P. Ros s l I s t i t ut o Nazi onal e di Fi si ca Nucl ear e I SS, I t al y G . Ger vi no I s t i t ut o Nazi onal e di Fi si ca Nucl ear e, Tor i no, I t al y Recei ved 1 June 1992 NUCLEAR I NSTRUMENTS & METHODS IN PHYSI CS RESEARCH Sect i on A The desi gn c r i t er i a of a sci nt i l l at or t el escope f or hi gh ener gy el ect r ons, consi st i ng of pl ast i c sci nt i l l at or s, a BGO pr eshower det ect or , a segment ed BGO cal ori met er and an aer ogel Cher enkov count er ar e di scussed . The per f or mance of t he t el escope is descr i bed usi ng t he dat a col l ect ed in an i ncl usi ve el ect r on scat t er i ng experi ment ar ound 1 GeV, with emphasi s on t he ef f i ci ency to el ect r ons, whi ch is enhanced by t he anal ysi s of t he compl et e i nf ormat i on pr ovi ded by such a mul t i det ect or syst em. 1 . I nt r oduct i on The el ect romagnet i c i nt er act i on is an i deal pr obe to st udy t he hadr oni c st r uct ur e of t he nucl eus . It is de- scr i bed by quant um el ect r odynam i cs, it is suf f i ci ent l y weak to be comput ed in a per t ur bat i ve appr oach and it is sensi t i ve to t he ent i r e nucl ear vol ume . The el ect r on scat t er i ng has so f ar suppl i ed a ver y accur at e and or gani c i nf ormat i on on t he char ge di st r i but i on, on si n- gl e par t i cl e st at e char act er i st i cs and al so on nucl eon exci t ed st at es and t hei r behavi our in nucl ear mat t er . Magnet i c spect r omet er s have normal l y been used to det ect scat t er ed el ect r ons. Thei r mos t char act er i st i c per f or mance is t he hi gh moment um r esol ut i on (Op/ p 10 - 3 - 10 -4 ), and lim i t ed moment um accept ance (1 .1 <Pmax / Pmm < 2) . The sol i d angl e cover ed is t ypi cal l y of a f ew msr and Cher enkov count er s pr ovi de appr o- pr i at e el ect r on i dent i f i cat i on . El ect r on spect r omet er s based on sci nt i l l at i on coun- t er s can be a val i d al t er nat i ve wher e an ener gy r esol u- t i on of t he or der of a f ew per cent is compat i bl e with t he pr eci si on r equi r ed to t he experi ment . A sci nt i l l a- t i on t el escope coul d cover a muc h l ar ger sol i d angl e wi t hout bei ng lim i t ed in t he accept ed moment umr ange 0168- 9002/ 93/ $06. 00 C 1993 - El sevi er Sci ence Publ i sher s B.V. Al l r i ght s r eser ved and coul d al l ow t he si mul t aneous acqui si t i on of multi- pl e i nf ormat i ons f r om t he const i t uent det ect or s . For t he st udy of i ncl usi ve el ect r on scat t er i ng up to ' .~ GeV [ 1] of f an oxygen t ar get at t he Jet - Tar get f aci l i t y of t he I NFN Fr ascat i Nat i onal Labor at or i es we have devel oped such a spect r omet er . Thi s has r epr e- sent ed a good sol ut i on to t he space const r ai nt s of our experi ment al ar ea and has r esul t ed par t i cul ar l y sui t - abl e to t he ki nemat i cal condi t i ons of our experi ment wher e t he pr ot on and pi on backgr ound was a sever e pr obl em . 2 . The sci nt i l l at i on t el escope The schemat i c l ayout of our t el escope is shown in fig. 1 . The r eact i on pr oduct s ar e i nt er cept ed in or der by a t hi n si ngl e pl ast i c sci nt i l l at or , an aer ogel Cher enkov count er , a segment ed t hi ck pl ast i c sci nt i l l a- t or , a BGOpr eshower count er and a mat ri x of 20 BGO cr yst al s ar r anged (5 x 4) in a car bon f i br e basket . The first el ement is a t hi n pl ast i c sci nt i l l at or ( l abel ed ( a) in fig . 1) of si ze 2.5 x 3.0 x 0 .2 cm 3 . Thi s det ect or di st i ngui shes char ged par t i cl es f r om neut r al par t i cl es