Broude, C

Goldring, G

Hass, M

CERN Document Server

.@MHc5machines of this type in the world which can handle Be, we have implanted stable ’Be OCR Outputof the 300 keV ion implantation machine at Technion in Haifa, which is one of the_fewmeasurement of the cross-section. The first part has already been started. Making usetarget conditions, ii) ion source development and target production and iii)The research will be divided into three separate stages: i) establishment of optimumconventional targets were used.possible to overcome the difficulties encountered in previous experiments in whichthickness (which makes ot-ot coincidence experiments possible). All this should make itshallow, accurately known depth distribution of the ’ B ions and iv) a very small targetcomplete homogeneity, ii) accurate knowledge of the number of ’ Be ions, iii) aion implanted target will have the following advantages over those previously used: i)already been pioneered at ISOLDE for the preparation of Na targets [9]. Such an22entirely new approach conceming ’ Be target preparation but the method itself hasWe want to produce ’ Be targets by implanting a thin film with ’ Be ions. This is andetermination for the Be(p,y)Be reaction.78Target problem is generally perceived to be the weak link in the cross-sectionof the final targets (purity, homgenety and target thickness) are not well defined. TheThis is done bye a rather difficult chemical procedure and as a result the characteristicstarget for these measurements, had to be prepared from unstable ’ Be('l`1/2:53 days).due, in part, to the large discrepancies between apparently similar experiments. Thereaction has been studied many times, doubts persist about the accuracy of the resultssun and for solving the so-called "solar neutrino puzzle"[l-8]. Even though thisBe(p,y)Be. This cross-section is of fundamental importance for the physics of the7*8accurate information than is presently available on the cross-section for the reactionThe objective of the research we want to propose is to provide more reliable andContactman: M.LindroosSpokesman: M.HassL.Weissman1)M.Hass1), c.Bmnae1>,o.o¤1anng1>,R.Kn1isn2>, M.Lindroos3), H.Ravn3) and9W·@C Eu M G Ep Q; CERN3) - TECHNION2) - Weizmann rnsnnne nr Sciencel_{<J’rr\"*y*9, ,;; FABRICATION OF IMPLANTED 7Be TARGETSLETTER OF INTENT3.3.1994*300005457[SC/{lgPatriciaZAMPAGLIONE CERN/ISC 94-5NCERN LIBRARIES, GENEVAJ 1 1 3[6] S.A.Bludman et al., Phys.Rev. D47(1993)2220 OCR Output[5] E.Kh.Akhnedov et al, Phys.Lett. B303(l993)85[4] P.Anselmann et al, -GALEX collaboration, Phys.Lett. 285(1992)390[3] P.Anselmann etal, -GALEX collaboration, Phys.Lett. 285(1992)376and refemecs therein[2] B.W.Filippone, A.J.Elwyn, C.N.davids, D.D.Koetke, Phys.Rev.C28(1983)2222;[1] C.W.Johnson, E.Kolbe, S.E.Koonin, K.Langake, Astrophysics J. 392(1912)320Referencesthe "solar neutrino puzzle"determination of the astrophysically important cross-section and should help to settleThe experiment we want to propose will yield a most significant improvement in thethe production of one target.with a beam intensity of 1* 10V atoms/(s*ttA) would require 4 shifts of implantation forcoul be expected. We need approximately 10Be atoms in the target matrix which14is commissioned. With these improvements a ’ Be beam of 6* 10-6* 10atoms/(s*ttA)8910%. The target thickness could be raised by a factor of 3 once the 40 cm long targetsuccessful ion-source development programme could possibly raise the efficiency topresent ion-source it would result in an ion-bearn intensity of 7* 100 atoms/(s*uA) . Ag/cme at the 1 GeV BOOSTER proton-beam is about 7*10atoms/(s*uA) . With the10ion-source as anode insulator. The production rate of ’ Be in a graphite target of 20losses were found to be due to exchange reactions with the stable BeO present in thesource and a more uniform target heating efficiencies of 0.01% were achieved. Theefficiency of only 0.0001-0.001%. In off-line measurements with a hot plasma ionJudging from the cross—section of the reaction this corresponds to an ion-sourceirradiated with 910 MeV 5He beam combined with a hot plasma discharge ion-source.atoms/(s*lLA) has been observed emerging from a 122g/cm·* Tantalum targetcondition for making radioactive ion beams of Be. On·line an Be beam of 2* 1011readily released from Graphite and Tantalum target materials which is a necessaryat ISOLDE. At present Be has been found in off-line measurements been found to beion source development programme of the feasibility of producing radioactive targetsBefore submitting a formal proposal we want to have clear indication from our jointsection, will take place at the Weizmann institute.(T echnion). The third part of the proposed research, the measurement of the crossworkshop resources and know-how concerning ionization and transport of Befrom the two extemal institutes could be in form of e.g. manpower for target tests,present we propose a joint CERN-Technion-Wl development effort. Contributionsradioactive beam intensities further ion source development has to take place. Atradioactive targets at the ISOLDE facility of CERN. However, to achieve sufficientSpectroscopy (SIMS). The second part ultimately aims at the production of theinvestigated before and after proton bombardment using Secondary Ion MassAccelerator Laboratory. Implantation profile and sample homogeneity will bep.A proton beam at E(p)=l MeV at the Van der Graaf of the Weizmann institutenecessary, by utilizing the High Voltage Platform) . These will be irradiated with a 4into different target matrices at enegies which will be available at ISOLDE (ifB58(1991)174[9] H.Ravn, W.H.Schu1te, C.Rolfs, F.B.Waanders and R.W.Kavanagh, Nucl.Intr.Meth.1990) vol. 12, p. 143Adelaide, Australia, 1989, edited by R.J.Protheroe (U. of Adelaide Press, Adelaide,[8] R.Davis, Jr. et al, in Proceedings of the 21st Intemational Cosmic Ray Conference,[7] J .N.Bahcall and M.H.Pinsonneau1t, Rev.Mod.Phys. 64(1992)885

Fabrication of implanted $^{7}$ Be targets

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Fabrication of implanted 7^{7}7Be targets

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Fabrication of implanted $^{7}$ Be targets