ENTRY M0672 20050614 M037M067200000001 SUBENT M0672001 20050614 M037M067200100001 BIB 16 45 M067200100002 TITLE Fission cross section and fissility of 209Bi by 60 - M067200100003 270 MeV tagged photons. M067200100004 AUTHOR (M.L.TERRANOVA,G.YA.KEZERASHVILI,V.A.KISELEV, M067200100005 A.M.MILOV,S.I.MISHNEV,I.YA.PROTOPOPOV,V.N.ROTAEV, M067200100006 D.N.SHATILOV,O.A.P.TAVARES) M067200100007 INSTITUTE (4RUSSIB,2ITYFRA,3BZLRIO) M067200100008 REFERENCE (J,JP/G,22,1661,1996) M067200100009 INC-SOURCE (MPH,COMPT,LASER) Tagged photons produced by the M067200100010 compton and backscattering gamma quanta at M067200100011 backscattering laser photon facility ROKK-2 at the M067200100012 VEPP-3 storage ring. M067200100013 FACILITY (ESTRG,4RUSSIB) ROKK-2 facility of Budker Institute M067200100014 of Nuclear Physics, Novosibirsk. M067200100015 SAMPLE The bismuth targets consisted of high-purity metal M067200100016 films prepared by vacuum evaporatuion on alumonoum M067200100017 plates 300 micron thick. The targets (4 cm in M067200100018 diameter) were licated insude the FF vessel at a M067200100019 distance of 3 mm from the multiwire spark counter M067200100020 anodes. M067200100021 DETECTOR (MWSC) Nuclear fission fragment detector (FF) based on M067200100022 multiwire spark counters (SC). M067200100023 METHOD (EXTB,SITA) M067200100024 ANALYSIS The direct fission fragment track counting. M067200100025 MONITOR (92-U-238(G,F),,SIG) M067200100026 REL-REF (R,,A.S.ILJINOV+,J,NP/A,539,263,1992) 238U monitor M067200100027 absolute fission cross section. M067200100028 ERR-ANALYS (DATA-ERR) Statistical errors. M067200100029 STATUS (CURVE) Data from Fig. 2 were compiled at the Russia M067200100030 MSU SINP CDFE by V.V.VARLAMOV. M067200100031 COMMENT Tagged photons produced by the ROKK-2 facility have M067200100032 been used to measure the photofission cross section M067200100033 of 209Bi in the energy range 60 - 270 MeV. Fission M067200100034 events were detected by using a nuclear fragment M067200100035 detector based on multiwire spark counters. M067200100036 Fissility values have been deduced and compared with M067200100037 available data obtained with monochromatic photons M067200100038 in othder laboratories. These data have been M067200100039 analysed in the framework of a two-step model wich M067200100040 considers the primary photointegration occuring via M067200100041 the quasi-deuteron and/or photomesonic processes, M067200100042 followed by mechanism of evaporation-fission M067200100043 competition for the excited residual nucleus. The M067200100044 model was found to reproduce the main experimental M067200100045 features of 209Bi photofissility up to 300 MeV. M067200100046 HISTORY (20050606C) M067200100047 ENDBIB 45 0 M067200100048 NOCOMMON 0 0 M067200100049 ENDSUBENT 48 0 M067200199999 SUBENT M0672002 20050614 M037M067200200001 BIB 1 1 M067200200002 REACTION (83-BI-209(G,F),,SIG) M067200200003 ENDBIB 1 0 M067200200004 NOCOMMON 0 0 M067200200005 DATA 3 10 M067200200006 EN DATA DATA-ERR M067200200007 MEV MB MB M067200200008 60. .015 .075 M067200200009 89.3 .306 .078 M067200200010 124.1 .448 .079 M067200200011 148.3 1.015 .082 M067200200012 173.6 1.731 .269 M067200200013 178.7 2.015 .284 M067200200014 208.9 2.388 .388 M067200200015 223.7 3.313 .672 M067200200016 239.1 4.575 .587 M067200200017 270. 6.594 .321 M067200200018 ENDDATA 12 0 M067200200019 ENDSUBENT 18 0 M067200299999 ENDENTRY 2 0 M067299999999