ENTRY D6075 20090803 D069D607500000001 SUBENT D6075001 20090803 D069D607500100001 BIB 14 63 D607500100002 TITLE Determination of the 233-Pa (n, f) reaction cross D607500100003 section from 11.5 to 16.5 MeV neutron energy by the D607500100004 hybrid surrogate ratio approach D607500100005 AUTHOR (B.K.Nayak, A.Saxena, D.C.Biswas, E.T.Mirgule, D607500100006 B.V.John, S.Santra, R.P.Vind, R.K.Choudhury, D607500100007 S.Ganesan) D607500100008 INSTITUTE (3INDTRM) D607500100009 REFERENCE (J,PR/C,78,061602,2008) D607500100010 FACILITY (VDGT,3INDTAT) D607500100011 SAMPLE A self-supporting thorium target of thickness 2.0 D607500100012 Mg/cm**2 was bombarded with a 6-Li beam. D607500100013 DETECTOR (SOLST,SISD) a solid state delta E - E telescope of D607500100014 thickness 150.0 micro millimeter to 1.0 millimeter was D607500100015 kept at 90 degree with respect to the beam direction D607500100016 around the transfer grazing angle to identify the D607500100017 projectile-like-fragments (PLF). A 16 strip solid D607500100018 state detector (each strip of size 2.0 X 64.0 mm) was D607500100019 placed at a back angle covering the laboratory angular D607500100020 range of 141-158 degree to detect fission fragments in D607500100021 coincidence with PLFs. D607500100022 METHOD (EDE) The proton, deuteron, triton, alpha and 6-Li D607500100023 particles are uniquely identified by plotting delta D607500100024 E against the delta E + E. This plot was transformed D607500100025 to create an effective particle identification versus D607500100026 energy plot. D607500100027 INC-SOURCE A self-supporting thorium was bombarded with 6-Li D607500100028 beam of energy 38.0 MeV from a 14 MV Pelletron D607500100029 accelerator at Mumbai. D607500100030 ANALYSIS (SURGT) The 234-Pa and 236-U compound systems have D607500100031 been populated at overlapping excitation energies in D607500100032 the same experiment through 232-Th (6-Li,A) 234-Pa and D607500100033 232-Th (6-Li,D) 236-U transfer channels at E (lab) = 38D607500100034 MeV, and the absolute surrogate method is used to D607500100035 determine fission decay probabilities of the above D607500100036 compound nuclei by dividing the number of PLF-fission D607500100037 coincidences by the associated PLF-singles data. The D607500100038 experimental values of fission decay probability D607500100039 ratios of 234-Pa and 236-U compound nuclei at the same D607500100040 excitation energies have been used to deduce the 233-PaD607500100041 (n,f) cross-section using a surrogate ratio approach. D607500100042 ERR-ANALYS (ERR-S) The uncertainties shown in the measured cross D607500100043 section is due to the statistics of coincidence D607500100044 counts in each energy beam. D607500100045 COMMENT A new hybrid surrogate ratio approach has been D607500100046 employed to determine neutron-induced fission cross D607500100047 sections of 233-Pa in the energy range of 11.5 to D607500100048 16.5 MeV for the first time. The 233-Pa D607500100049 (n,f) cross sections are deduced from the measured D607500100050 fission decay probabilities ratios of 234-Pa and D607500100051 236-U compound nuclei using the surrogate ratio D607500100052 method. The 233-Pa (n,f) cross section data from the D607500100053 present experiment along with the data from the D607500100054 literature, covering the neutron energy range of 1.0 D607500100055 to 16.5 MeV have been compared with the predictions D607500100056 of statistical model code EMPIRE-2.19. While the D607500100057 present data are consistent with the model D607500100058 predictions, there is a discrepancy between the D607500100059 earliear experiment data and EMPIRE-2.19 predictions D607500100060 in the neutron energy range of 7.0 to 10.0 MeV. D607500100061 STATUS (APRVD)Entry approved by Dr. B. K. Nayak D607500100062 HISTORY (20090803C)Compiled by Mr.Paresh Prajapati of The 3D607500100063 M. S. University of Baroda and Dr. S. Ganesan of D607500100064 Reactor Physics Design Division, B.A.R.C, Mumbai. D607500100065 ENDBIB 63 0 D607500100066 NOCOMMON 0 0 D607500100067 ENDSUBENT 66 0 D607500199999 SUBENT D6075002 20090803 D069D607500200001 BIB 4 8 D607500200002 REACTION ((90-TH-232(3-LI-6,A+F),PAR,SIG)/ D607500200003 (90-TH-232(3-LI-6,D+F),PAR,SIG)) D607500200004 EN-SEC (E-EXC-NM,91-PA-234) D607500200005 (E-EXC-DN,92-U-236) D607500200006 STATUS (TABLE) Data has been provided by author and analysed D607500200007 by Mr. Paresh Prajapati, MSU, Baroda. D607500200008 COMMENT In reaction code, it is a ratio of fission decay D607500200009 probability of compound nuclei. D607500200010 ENDBIB 8 0 D607500200011 COMMON 1 3 D607500200012 EN D607500200013 MEV D607500200014 38.0 D607500200015 ENDCOMMON 3 0 D607500200016 DATA 4 6 D607500200017 E-EXC-NM E-EXC-DN DATA ERR-S D607500200018 MEV MEV NO-DIM NO-DIM D607500200019 17. 17. 0.50184 0.028 D607500200020 18. 18. 0.51408 0.027 D607500200021 19. 19. 0.49964 0.021 D607500200022 20. 20. 0.47535 0.020 D607500200023 21. 21. 0.52743 0.026 D607500200024 22. 22. 0.68700 0.049 D607500200025 ENDDATA 8 0 D607500200026 ENDSUBENT 25 0 D607500299999 ENDENTRY 2 0 D607599999999