ENTRY 22863 20041222 00002286300000001 SUBENT 22863001 20041222 00002286300100001 BIB 12 61 2286300100002 TITLE Production of neutron-rich nuclei in fission induced 2286300100003 by neutrons generated by the P+C-13 reaction at 2286300100004 55-MeV. 2286300100005 AUTHOR (L.STROE, G.LHERSONNEAU, A.ANDRIGHETTO, P.DENDOOVEN, 2286300100006 J.HUIKARI, H.PENTTILA, K.PERAJARVI, L.TECCHIO, Y.WANG) 2286300100007 INSTITUTE (2ITYPAD) 2286300100008 (2SF JYV) 2286300100009 REFERENCE (J,EPJ/A,17,57,2003) 2286300100010 HISTORY (20041129C) 2286300100011 (20041222U) Last checking has been done. 2286300100012 SAMPLE A 25*25-mm uranium target of 15-mg/cm**2 thickness 2286300100013 was used. 2286300100014 DETECTOR (COIN,GELI,SCIN).The gamma-rays were observed with 2286300100015 a planar Ge and two coaxial Ge-detectors placed at 2286300100016 about 8-cm from the collection spot. The energy range 2286300100017 covered was from 15-KeV to 2-MeV and the total peak 2286300100018 efficiency was 8.E-03 at 13-MeV. 2286300100019 .In order to suppress the room background, the Ge- 2286300100020 detectors were operated in coincidence with a 40% 2286300100021 efficiency thin plastic scintillator triggered by 2286300100022 beta-particles, built as a cylinder surrounding the 2286300100023 collection spot. 2286300100024 FACILITY (OLMS,2SF JYV) 2286300100025 METHOD (ASEP) 2286300100026 ADD-RES (COMP).The results, position of the maximum in the 2286300100027 (z,a)-plane, width and magnitude, are very comparable 2286300100028 with those where the neutron are generated by 2286300100029 bombardment of natural C-12 graphite with 50-MeV 2286300100030 deuterons. 2286300100031 COMMENT *By authors*.Depending on the geometry of the 2286300100032 converter/target assembly the isotopic yields, however,2286300100033 are a factor of 2-3 lower due to less efficient 2286300100034 production of neutrons per primary projectile, 2286300100035 especially at small forward angles. 2286300100036 *By authors*.The efficiency of mass separation cannot 2286300100037 be controlled well enough to make its variation 2286300100038 negligible with respect to other sources of errors in 2286300100039 measurements. The procedure adopted to extract isotopic2286300100040 cross sections is therefore based on the following two 2286300100041 steps. First, the mass cross sections are calculated 2286300100042 for the neutron spectrum experienced by the target. 2286300100043 This supposes the knowledge of mass cross section curve2286300100044 versus neutron energy and of the spectral distribution 2286300100045 of the neutrons impinging on the fissile target. 2286300100046 Subsequently, for the certain number of masses selected2286300100047 with the mass separated the relative cross section of 2286300100048 isobars are measured. Absolute value are obtained by 2286300100049 normalization using the fact that the mass cross 2286300100050 section is sum of the cross sections of individual 2286300100051 isobars. This method is possible owing to the fast 2286300100052 separator time, much shorter than beta-decay lifetimes 2286300100053 of thedetectable isotopes and the negligible element 2286300100054 selectivity of the igisil method. The problem of 2286300100055 measuring relative cross section is thus reduced to 2286300100056 that of measuring the intensities of the beams of the 2286300100057 various isobars delivered by separator. 2286300100058 *By compiler*.En is the average neutron energy. 2286300100059 INC-SOURCE A 55-MeV proton beam from K-130 cyclotron bombarded 2286300100060 a C-13 thick target made of pressed powder with a 2286300100061 density of 736-mg/cm**3 and a length of 50-mm, placed 2286300100062 inside a cylindrical Al-container of 1-mm thickness. 2286300100063 ENDBIB 61 0 2286300100064 COMMON 1 3 2286300100065 EN 2286300100066 MEV 2286300100067 15.2 2286300100068 ENDCOMMON 3 0 2286300100069 ENDSUBENT 68 0 2286300199999 SUBENT 22863002 20041222 00002286300200001 BIB 4 5 2286300200002 REACTION (92-U-0(N,F)ELEM/MASS,CUM,FY,,REL) 2286300200003 COMMENT *By authors*.Experimental cumulative yields. 2286300200004 Corrections for half-lifes being performed. 2286300200005 STATUS .Table in main ref 2286300200006 ERR-ANALYS (DATA-ERR).The error is reported by authors in table. 2286300200007 ENDBIB 5 0 2286300200008 NOCOMMON 0 0 2286300200009 DATA 4 26 2286300200010 ELEMENT MASS DATA DATA-ERR 2286300200011 NO-DIM NO-DIM ARB-UNITS ARB-UNITS 2286300200012 37. 94. 5.2 0.6 2286300200013 37. 95. 1.6 0.2 2286300200014 38. 94. 5.4 1.2 2286300200015 38. 95. 2.1 0.5 2286300200016 39. 94. 6.5 0.9 2286300200017 39. 102. 0.8 0.2 2286300200018 40. 102. 7.4 1.1 2286300200019 41. 102. 12.4 1.5 2286300200020 42. 108. 2.2 1.1 2286300200021 43. 102. 15.4 2. 2286300200022 43. 108. 2.9 0.3 2286300200023 44. 108. 2.3 0.6 2286300200024 44. 112. 1. 0.3 2286300200025 45. 108. 2.8 0.7 2286300200026 45. 112. 2.2 0.4 2286300200027 46. 118. 0.9 0.2 2286300200028 47. 118. 2. 0.5 2286300200029 48. 124. 0.5 0.2 2286300200030 49. 124. 1.4 0.4 2286300200031 50. 130. 1. 0.2 2286300200032 50. 132. 0.8 0.2 2286300200033 51. 130. 2.2 0.3 2286300200034 51. 132. 3.4 0.4 2286300200035 53. 140. 0.9 0.2 2286300200036 54. 140. 7.3 0.8 2286300200037 55. 140. 12.1 1.4 2286300200038 ENDDATA 28 0 2286300200039 ENDSUBENT 38 0 2286300299999 SUBENT 22863003 20041222 00002286300300001 BIB 2 2 2286300300002 REACTION (92-U-0(N,F)MASS,,ZP) 2286300300003 STATUS .Table in main ref 2286300300004 ENDBIB 2 0 2286300300005 NOCOMMON 0 0 2286300300006 DATA 2 10 2286300300007 MASS DATA 2286300300008 NO-DIM NO-DIM 2286300300009 94. 37.6 2286300300010 95. 37.9 2286300300011 102. 40.5 2286300300012 108. 42.7 2286300300013 112. 44.2 2286300300014 118. 46.4 2286300300015 124. 48.5 2286300300016 130. 50.7 2286300300017 132. 51.5 2286300300018 140. 54.4 2286300300019 ENDDATA 12 0 2286300300020 ENDSUBENT 19 0 2286300399999 ENDENTRY 3 0 2286399999999