ENTRY L0238 20181209 L038L023800000001 SUBENT L0238001 20181209 L038L023800100001 BIB 11 54 L023800100002 TITLE Measurement of the 80Se(gamma,n) reaction with L023800100003 linearly polarized gamma rays L023800100004 AUTHOR (S.A.Yates,B.Fallin,C.R.Howell,Krishichayan, L023800100005 W.Tornow,S.M.Grimes) L023800100006 INSTITUTE (1USATNL,1USAOHO) L023800100007 REFERENCE (J,PR/C,98,054621,2018) L023800100008 FACILITY (ESTRG,1USATNL) Experiment performed at HIgS facility L023800100009 at Duke University, generated circularly polarized L023800100010 and monoenergetic photon beams. L023800100011 SAMPLE (34-SE-80,ENR=0.9945) The selenium target consisted of L023800100012 2.99 g of enriched 80Se powder, encased in a plastic L023800100013 cylinder. The volume containing the 80 Se powder was L023800100014 20-mm diameter x 5-mm long.The front and back ends of L023800100015 the plastic cylinder were 1.5 mm thick each, and the L023800100016 surrounding circular wall was 5.5 mm thick. L023800100017 DETECTOR (SCIN) Three liquid-scintillation detectors filled L023800100018 with BC501-A fluid were placed around the target. L023800100019 The front of each detector was covered with a 2.4 mm L023800100020 thick lead disk to desensitize the scintillators to L023800100021 the prompt gamma ray flash. L023800100022 Position of individual detectors with respect to L023800100023 sample and gamma ray beam was as follows L023800100024 Detector Distance(cm) Theta(deg) Phi(deg) L023800100025 1. 55.3+-0.2 90 180 L023800100026 2. 55.6+-0.2 90 270 L023800100027 3. 52.8+-0.2 135 0 L023800100028 (SCIN) The number of photons incident on the target L023800100029 was measured with the thin plastic scintillator paddle L023800100030 that was located upstream. L023800100031 METHOD (TOF,PSD) Energy of emitted neutrons were determined L023800100032 using time-of-flight. Excellent pulse shape properties L023800100033 of BC501-A was used to identify neutrons. Gamma ray L023800100034 peak position was used as internal time reference. L023800100035 INC-SOURCE (LCS) The HIgS facility produces a quasi- L023800100036 monoenergetic Compton backscattered photon beam L023800100037 tunable in wide energy range with either linear or L023800100038 circular polarization. A high-flux photon beam is L023800100039 created by colliding relativistic electron beam L023800100040 bunches, circulating in a storage ring, with photon L023800100041 pulses inside the high-power optical cavity of a free- L023800100042 electron laser. The 15.6-MeV gamma ray beam was L023800100043 produced by Compton backscattering of FEL photons with L023800100044 wavelength 454.7 nm off 624-MeV electrons. The gamma L023800100045 ray beam at the HIGS is pulsed with a bunch width of L023800100046 300 ps FWHM and a period of 180 ns between pulses. L023800100047 This time structure enables neutron energy L023800100048 determinations by time-of-flight methods. L023800100049 ANALYSIS Angle-integrated differential cross-section data were L023800100050 integrated with respect to excitation energy. Due to L023800100051 the 600-keV energy threshold, measured cross section L023800100052 data were extrapolated from the maximum excitation L023800100053 energy of the measurements to the theoretical maximum L023800100054 excitation energy. L023800100055 HISTORY (20181209C) Compiled by S.H. L023800100056 ENDBIB 54 0 L023800100057 NOCOMMON 0 0 L023800100058 ENDSUBENT 57 0 L023800199999 SUBENT L0238002 20181209 L038L023800200001 BIB 3 13 L023800200002 REACTION (34-SE-80(G,N)34-SE-79,,SIG) L023800200003 STATUS (TABLE) Data taken from tab.3 of the reference L023800200004 ERR-ANALYS (ERR-1) Systematic uncertainty in plastic paddle L023800200005 efficiency L023800200006 (ERR-2) Systematic uncertainty in neutron detector L023800200007 efficiency L023800200008 (ERR-3) Systematic uncertainty in neutron effective L023800200009 transmission L023800200010 (ERR-SYS) Total systematic uncertainty L023800200011 (ERR-T) The total uncertainties reflect both the L023800200012 totalsystematic uncertainty of the differential L023800200013 cross-section measurements and the extrapolation L023800200014 uncertainty, added in quadrature. L023800200015 ENDBIB 13 0 L023800200016 COMMON 5 3 L023800200017 EN-RSL ERR-1 ERR-2 ERR-3 ERR-SYS L023800200018 PER-CENT PER-CENT PER-CENT PER-CENT PER-CENT L023800200019 3. 7. 4. 5. 10. L023800200020 ENDCOMMON 3 0 L023800200021 DATA 3 3 L023800200022 EN DATA ERR-T L023800200023 MEV MB MB L023800200024 15.6 108.7 15.0 L023800200025 15.8 112.9 16.1 L023800200026 16.0 113.1 15.1 L023800200027 ENDDATA 5 0 L023800200028 ENDSUBENT 27 0 L023800299999 ENDENTRY 2 0 L023899999999