ENTRY 13746 20100625 13641374600000001 SUBENT 13746001 20100625 13641374600100001 BIB 13 50 1374600100002 INSTITUTE (1USAANL) 1374600100003 REFERENCE (J,PR/C,61,047601,2000) 1374600100004 AUTHOR (J.K.Hwang,A.V.Ramayya,J.H.Hamilton,C.J.Beyer, 1374600100005 J.Kormicki,X.Q.Zhang,A.Rodin,A.Formichev,J.Kliman, 1374600100006 L.Krupa,G.M.Ter Akopyan,Yu.Ts.Oganessian, G.Hubarian, 1374600100007 D.Seweryniak,C.J.Lister,R.V.F.Janssens,I.Ahmad, 1374600100008 M.P.Carpenter,J.P.Greene,T.Lauritsen,I.Wiedenhoever, 1374600100009 W.C.Ma,R.B.Piercey,J.D.Cole) 1374600100010 TITLE 5He ternary fission yields of 252Cf and U235(n,f) 1374600100011 FACILITY Gammasphere array at Argonne National Laboratory 1374600100012 SAMPLE 252Cf source (30 microCi) sandwiched between two Au 1374600100013 foils each 19 mg/cm**2 in thickness. An 0.84 mg/cm**21374600100014 Mylar foil is placed On each side of the Cf sample. 1374600100015 METHOD (EDE) Energy distribution analysis. 1374600100016 No reliable data was obtained for alpha energies below1374600100017 9.0 MeV, the low energy cutoff of the measurement. 1374600100018 DETECTOR (TELES) 2 DE-E Si detector telescopes installed in the 1374600100019 center of the Gammasphere array. Each DE-E telescope 1374600100020 included one DE detector (15 microns thick and 10x10 1374600100021 mm**2 area) and one E strip detector (400 microns 1374600100022 thick and 60x60 mm**2 in area) with 29 strips. 1374600100023 The DE and E telescopes, installed at 6 and 40 mm 1374600100024 from the source, respectively, provided Z and A 1374600100025 identification for all charged light particles. 1374600100026 MONITOR Energy calibration of telescopes performed with 224Ra 1374600100027 and 228Th radioactive source and 6.2-MeV alpha peak 1374600100028 from decay of 252Cf deposited on surface of Au foil. 1374600100029 CORRECTION Corrected for: 1374600100030 . energy loss of alpha particles in Au foil, 1374600100031 . 6.2-MeV decay alpha particles from accidental 1374600100032 contamination of surface of Au foil with the source 1374600100033 material. 1374600100034 ANALYSIS Shape of energy spectrum of ternary alpha particles 1374600100035 analyzed. Low energy tail was attributed to alpha 1374600100036 particles originating from 5He emission. Contribution 1374600100037 from the breakup of 6He and 8He was neglected as <1%. 1374600100038 Observed energy spectra fitted with Gaussian functions 1374600100039 to disentangle contributions of 5He and 4He. 1374600100040 The only requirement of the fitting procedure is that 1374600100041 widths of the two Gaussian distributions have the same1374600100042 FWHM. 1374600100043 The small additional spread in momentum which is 1374600100044 contribution of the breakup of 5He to distribution 1374600100045 imparted by the fission is neglected in this approach.1374600100046 STATUS (TABLE) Data taken from Table I in reference. 1374600100047 No reply to author proof from J.K. Hwang 1374600100048 HISTORY (20010730C) IS 1374600100049 (20050722C) DR Reference corrected 1374600100050 (20100625A) VM: BIB updates. 1374600100051 Subentry 13746.002 corrected. 1374600100052 ENDBIB 50 0 1374600100053 NOCOMMON 0 0 1374600100054 ENDSUBENT 53 0 1374600199999 SUBENT 13746002 20100625 13641374600200001 BIB 5 18 1374600200002 REACTION ((98-CF-252(0,F)ELEM/MASS,TER,FY)/ 1374600200003 (98-CF-252(0,F)ELEM,TER,FY)) 1374600200004 ERR-ANALYS (DATA-ERR) Absolute uncertainty given. 1374600200005 Uncertainties depend on low-energy cutoff of alpha 1374600200006 spectra. 1374600200007 CRITIQUE ** BY AUTHOR ** Application of method with 5He-particle1374600200008 energy fixed at 15.4 MeV, as reported by of Cheifetz, 1374600200009 to data of Loveland for 252Cf, and of D'hondt et al. 1374600200010 and Caitucoli et al. for 235U(n,f), where the alpha 1374600200011 spectra extend to ~0.1MeV, leads to ternary 5He yields1374600200012 much larger than the 4He data and to very different 1374600200013 FWHM fit for the two He isotopes. This is at variance1374600200014 with the experimental observation that, for ternary 1374600200015 particles of the same charge, widths of energy 1374600200016 distributions are independent of mass. 1374600200017 REL-REF (D,,Cheifetz+,J,PRL,29,805,1972) 1374600200018 HISTORY (20030107A) Reaction updated. 1374600200019 (20100625A) Reaction quantity corrected. 1374600200020 ENDBIB 18 0 1374600200021 COMMON 1 3 1374600200022 ELEMENT 1374600200023 NO-DIM 1374600200024 2. 1374600200025 ENDCOMMON 3 0 1374600200026 DATA 4 2 1374600200027 MASS DATA -DATA-ERR +DATA-ERR 1374600200028 NO-DIM NO-DIM NO-DIM NO-DIM 1374600200029 4. 79.6 24.4 12.0 1374600200030 5. 20.4 2.9 21.9 1374600200031 ENDDATA 4 0 1374600200032 ENDSUBENT 31 0 1374600299999 ENDENTRY 2 0 1374699999999