ENTRY M0664 20050221 0000M066400000001 SUBENT M0664001 20050221 0000M066400100001 BIB 14 50 M066400100002 TITLE Cross section measurements of the 181Ta(g,n)180Ta M066400100003 reaction near threshold and the p-process M066400100004 nucleosynthesis. M066400100005 AUTHOR (H.UTSUNOMIYA,H.AKIMUNE,S.GOKO,M.OHTA,H.UEDA, M066400100006 T.YAMAGATA,K.YAMASAKI,H.OHGAKI,H.TOYOKAWA,Y.-W.LUI, M066400100007 T.HAYAKAWA,T.SHIZUMA,E.KHAN,S.GORIELY) M066400100008 REFERENCE (J,PR/C,67,015807,2003) M066400100009 (J,NP/A,738,136,2004) M066400100010 INSTITUTE (2JPNKON,2JPNKTO,2JPNAIS,2JPNJAE,1USATAM,2FR PAR, M066400100011 2BLGBRU) M066400100012 FACILITY (ESTRG,2JPNAIS) Electron storage ring TERAS at the M066400100013 National Institute of Advanced Industrial Science M066400100014 and Technology (AIST). M066400100015 INC-SOURCE (QMPH,COMPT) Laser Compton scattering (LCS). M066400100016 DETECTOR (BF3) M066400100017 METHOD (RINGR) 8 BF3 proportional counters embeded in a M066400100018 polyethilene moderator cube; four of those located M066400100019 in a concentric ring at 11 cm from the beam axis, M066400100020 the other four at 13 cm. M066400100021 SAMPLE Tantalum disk 2mm thick and 20 mm in diameter. M066400100022 ANALYSIS Direct measurement. M066400100023 ERR-ANALYS Statistical errors. M066400100024 COMMENT New measurements of the photoneutron reaction on M066400100025 181Ta have been conducted with the AIST-LCS (laser M066400100026 Compton scattering) beam in the 7.8 - 12.0 MeV M066400100027 energy range. The major advantage of the present M066400100028 g-ray experiment is its intense peaking in the M066400100029 energy window of astrophysical interest, i.e., close M066400100030 to the neutron threshold. Details on photon beams M066400100031 from the laser Compton scattering, neutron counting, M066400100032 and experimental determination of the 181Ta M066400100033 photoneutron cross section are given. The present M066400100034 experimental data are in good agreemrnt with the M066400100035 IAEA evaluation. Reaction rate calculations at the M066400100036 Hauser-Feashbach statistical model are performed and M066400100037 confronted with the experimental data. The data M066400100038 provide constraints on the low-energy tail of the M066400100039 dipole strength function. It was found that among M066400100040 the three different models for the E1-strength M066400100041 considered, only the microscopic quasiparticle M066400100042 random phase approximation model can reproduce the M066400100043 extra strength observed in the 181Ta(g,n)180Ta M066400100044 reaction at energies of about 8.5 MeV. Such an M066400100045 experiment helps to improve the determination of the M066400100046 corresponding stellar photodisintegration rate of M066400100047 181Ta which directly influences the p-process M066400100048 production of 180Ta. M066400100049 STATUS (CURVE) The data from Fig. 8 have been digitized at M066400100050 the Russia MSU SINP CDFE by V.V.Varlamov. M066400100051 HISTORY (20050218C) M066400100052 ENDBIB 50 0 M066400100053 NOCOMMON 0 0 M066400100054 ENDSUBENT 53 0 M066400199999 SUBENT M0664002 20050221 0000M066400200001 BIB 1 1 M066400200002 REACTION (73-TA-181(G,N)73-TA-180,,SIG) M066400200003 ENDBIB 1 0 M066400200004 NOCOMMON 0 0 M066400200005 DATA 3 13 M066400200006 EN DATA DATA-ERR M066400200007 MEV MB MB M066400200008 7.8 10.6 5.5 M066400200009 8.2 21.5 6.7 M066400200010 8.6 30.6 6.1 M066400200011 8.9 33.3 6.7 M066400200012 9.4 56.7 5.6 M066400200013 9.7 52.4 8.2 M066400200014 10.2 93.9 6.1 M066400200015 10.3 76.7 5.9 M066400200016 10.5 97. 5.3 M066400200017 10.6 137. 6.2 M066400200018 11.1 185.5 5.6 M066400200019 11.5 288.3 5.6 M066400200020 12.0 297.7 5.3 M066400200021 ENDDATA 15 0 M066400200022 ENDSUBENT 21 0 M066400299999 ENDENTRY 2 0 M066499999999