ENTRY M0687 20060331 M040M068700000001 SUBENT M0687001 20060331 M040M068700100001 BIB 15 60 M068700100002 TITLE Isovector quadrupole resonance in 13C(g,n) reaction. M068700100003 AUTHOR (K.MAEDA,S.ITO,H.ITOH,O.KONNO,H.MATSUYAMA, M068700100004 T.MURAKAMI,T.SASAKI,T.SUDA,M.TAKEYA,T.TERASAWA) M068700100005 INSTITUTE (2JPNTOH) Tohoku University, Sendai, Physics M068700100006 Department, Graduate School of Science, Laboratory M068700100007 for Nuclear Science. M068700100008 (2JPNIPC) Institute of Physical and Chemical Research M068700100009 (RIKEN), Wako. M068700100010 (2JPNJPN) Ichinoseki National College of Technology, M068700100011 Ichinoseki. M068700100012 (2JPNKTO) Kyoto University, Department of Physics, M068700100013 Graduate School of Science. M068700100014 REFERENCE (J,JPJ,75,(3),034201,200603) M068700100015 FACILITY (LINAC,2JPNTOH) Laboratory of Nuclear Science. M068700100016 (SRING,2JPNTOH) Laboratory of Nuclear Science. M068700100017 INC-SOURCE (QMPH,TAGD) Tagged photons obtained at the Laboratory M068700100018 of Nuclear Science (LNS) of Tohoku University - an M068700100019 electron beam of 89.5 MeV from 300-MeV linear M068700100020 accelerator injected into the Sendai Stretcher Ring M068700100021 (SSTR) and extracted with an average duty factor of M068700100022 ~ 80 %, bremsstrahlung photons were produced by 3 M068700100023 micro-meter gold radiator and tagged by recoil M068700100024 electrons which were momentum analyzed in a photon M068700100025 tagging spectrometer. M068700100026 SAMPLE Target sample consisted of 98 % isotopically enriched M068700100027 13C powder, pressed into a thin-walled aluminium M068700100028 cylinder, 226 mm long and 70 mm in a diameter with M068700100029 100 micromm thick Mylar film on both ends, thickness M068700100030 is 4270 mg/cm**2. M068700100031 DETECTOR (SCIN) Three identical NE213 liquid scintillator M068700100032 detectors, thin plastic scintillator as veto counter M068700100033 placed in front of each neutron detector. M068700100034 METHOD (TOF) Flight path of 2.5 m with timing uncertainty M068700100035 delta-t = 0.72 ns (FWHM). M068700100036 ANALYSIS The absolute cross sections were deduced from the M068700100037 experimental yields taking into account the number M068700100038 of target atoms, the number of tagged photons, the M068700100039 photon tagging efficiency and the attenuation of the M068700100040 photons and neutrons in the target and the materials M068700100041 between the target and neutron detectors. M068700100042 ERR-ANALYS (ERR-S) Statistical uncertainty. M068700100043 STATUS (TABLE) Data received by e-mail from K.Maeda M068700100044 (2006.03.19) with help of N.Otsuka. M068700100045 ADD-RES Forward (55 deg) to backward (125 deg) asymmetry of M068700100046 13C(g,n)12C reaction - [Y(55) - Y(125)]/[Y(55) + M068700100047 Y(125)]. M068700100048 COMMENT The photoneutron cross section for 13C was measured M068700100049 in the tagged photon energy range Eg = 17 - 70 MeV. M068700100050 Substantial forward to backward asymmetry was M068700100051 observed above the giant dipole resonance region. M068700100052 The observed asymmetries were analyzed by the direct M068700100053 and semi-direct model, assuming two isovector E2 M068700100054 resonances, which locate at Ex = 39.9 (1.5) MeV with M068700100055 width = 8 (6) MeV and Ex = 43.2 (1.8) with width = M068700100056 13 (6) MeV. They are identified as the T> and T< M068700100057 isospin components of the isovector quadrupole M068700100058 strength, which exhaust most of the sum rule. M068700100059 HISTORY (20060330C) Data from Fig.5 compiled at the MSU SINP M068700100060 CDFE by Vladimir Varlamov used data tables obtained M068700100061 from Kazushige Maeda with the help of Naohiko Otsuka. M068700100062 ENDBIB 60 0 M068700100063 COMMON 2 3 M068700100064 EN-RSL ANG M068700100065 KEV ADEG M068700100066 1.7 90. M068700100067 ENDCOMMON 3 0 M068700100068 ENDSUBENT 67 0 M068700199999 SUBENT M0687002 20060331 M040M068700200001 BIB 4 10 M068700200002 REACTION (6-C-13(G,N)6-C-12,PAR,DA) M068700200003 EN-SEC (E-LVL,6-C-12) M068700200004 LEVEL-PROP (6-C-12,E-LVL=0.0,SPIN=0.,PARITY=+1.) M068700200005 (6-C-12,E-LVL=4.4,SPIN=2.,PARITY=+1.) M068700200006 REL-REF (N,M0324008,J.G.Woodworth+,J,NP/A,327,53,1979) M068700200007 Agree with the present data in the GDR region, but M068700200008 larger at photon energies above ~ 27 MeV. M068700200009 (N,L0048002,J.W.Jury+,J,PR/C,19,1684,1979) M068700200010 Agree with the present data in the GDR region, but M068700200011 larger at photon energies above ~ 27 MeV. M068700200012 ENDBIB 10 0 M068700200013 COMMON 2 3 M068700200014 E-LVL E-LVL M068700200015 MEV MEV M068700200016 0.0 4.4 M068700200017 ENDCOMMON 3 0 M068700200018 DATA 3 24 M068700200019 EN DATA ERR-S M068700200020 MEV MU-B/SR MU-B/SR M068700200021 17.4 220.6 24.8 M068700200022 18.7 85.2 10. M068700200023 20.1 115.9 15.2 M068700200024 21.5 236.9 14.8 M068700200025 23. 141.4 12.5 M068700200026 24.6 82.5 9. M068700200027 26.2 108.4 10.8 M068700200028 27.9 106.1 10.8 M068700200029 29.6 50.7 8.5 M068700200030 31.3 36.8 6.8 M068700200031 33. 60.7 10.1 M068700200032 34.8 43.8 8.5 M068700200033 36.6 42.1 9.1 M068700200034 38.4 37.7 7.7 M068700200035 40.1 42.4 9.1 M068700200036 42. 45.7 17.1 M068700200037 43.7 69.3 19.6 M068700200038 46.5 44.3 12.1 M068700200039 50. 29.6 11. M068700200040 53.4 3.2 5.6 M068700200041 56.7 38. 10.1 M068700200042 59.9 16. 8.1 M068700200043 63.5 35.8 10.4 M068700200044 67. 24.3 9. M068700200045 ENDDATA 26 0 M068700200046 ENDSUBENT 45 0 M068700299999 SUBENT M0687003 20060331 M040M068700300001 BIB 3 3 M068700300002 REACTION (6-C-13(G,N)6-C-12,PAR,DA) M068700300003 EN-SEC (E-LVL,6-C-12) M068700300004 LEVEL-PROP (6-C-12,E-LVL=15.1,SPIN=1.,PARITY=+1.) M068700300005 ENDBIB 3 0 M068700300006 COMMON 1 3 M068700300007 E-LVL M068700300008 MEV M068700300009 15.1 M068700300010 ENDCOMMON 3 0 M068700300011 DATA 3 14 M068700300012 EN DATA ERR-S M068700300013 MEV MU-B/SR MU-B/SR M068700300014 33. 136.2 10.1 M068700300015 34.8 147.4 11. M068700300016 36.6 123.7 10.2 M068700300017 38.4 94.8 8.5 M068700300018 40.1 86. 7.9 M068700300019 42. 112.9 21.8 M068700300020 43.7 93.5 20.2 M068700300021 46.5 71. 12.7 M068700300022 50. 74.3 13. M068700300023 53.4 52.7 11. M068700300024 56.7 21. 7.1 M068700300025 59.9 8.1 3.4 M068700300026 63.5 19.5 6.7 M068700300027 67. 18.8 7.1 M068700300028 ENDDATA 16 0 M068700300029 ENDSUBENT 28 0 M068700399999 ENDENTRY 3 0 M068799999999