ENTRY 13814 20010727 00001381400000001 SUBENT 13814001 20010727 00001381400100001 BIB 15 44 1381400100002 INSTITUTE (1USAANL) 1381400100003 REFERENCE (J,NP/A,157,520,1970) 1381400100004 AUTHOR (G.B.Beard, G.E.Thomas) 1381400100005 TITLE Gamma Rays from Thermal Neutron Capture in 28Si, 29Si 1381400100006 and 30Si. 1381400100007 FACILITY (REAC) Reactor CP-5. 1381400100008 INC-SOURCE (REAC) Reactor core with a neutron flux ~3E+13 1381400100009 n/cm**2 s. 1381400100010 INC-SPECT Reactor spectrum. 1381400100011 METHOD Internal-target facility used; target sample placed in 1381400100012 high-flux region of reactor and viewed (through a 1381400100013 collimator) by a detector located outside the reactor.1381400100014 Counting rate kept below 2000/sec to avoid peak 1381400100015 broadening. 1381400100016 DETECTOR (GELI) Ge(Li) detector having an active volume of 1381400100017 4 cm**3 and a resolution width of 6.7 keV for 7-MeV 1381400100018 gamma rays. The neutron flux on the detector was 1381400100019 reduced by collimators with neutron absorbing and 1381400100020 scattering materials (filters). 1381400100021 ANALYSIS A singles spectrum was taken by each sample and a 1381400100022 double escape spectrum was obtained by requiring 1381400100023 coincidence between the Ge(Li) detector signal and 1381400100024 the accompanying annihilation radiation observed with 1381400100025 two NaI(Tl) detectors. 1381400100026 Impurity lines were identified from the known 1381400100027 background of the system as well as by a comparison 1381400100028 with spectra from enriched isotopes. 1381400100029 MONITOR (14-SI-29(N,G)14-SI-30,,SPC,,SPA) Relative intensities 1381400100030 normalized to average of the intensities other 1381400100031 investigators have reported for strong 6744 keV. 1381400100032 Gamma-ray calibration based primarily on the peaks 1381400100033 from the 4945.43 keV transition in carbon. Relative 1381400100034 intensities were obtained by first summing the counts 1381400100035 under the individual peaks and then employing the 1381400100036 relative efficiency curve determined for the Ge(Li) 1381400100037 detector. 1381400100038 CORRECTION Corrected for the various thicknesses of the borated 1381400100039 polyethylene absorber. 1381400100040 ERR-ANALYS (ERR-S) Statistical errors in the peak areas given. 1381400100041 COMMENT The results from the 28Si(n,gamma)29Si reaction agreed 1381400100042 well with those from other investigations using 1381400100043 natural or enriched 28Si as targets. 1381400100044 HISTORY (20010630C) IS 1381400100045 (20010727A) BIB correction. 1381400100046 ENDBIB 44 0 1381400100047 COMMON 1 3 1381400100048 EN-DUMMY 1381400100049 EV 1381400100050 0.0253 1381400100051 ENDCOMMON 3 0 1381400100052 ENDSUBENT 51 0 1381400199999 SUBENT 13814002 20010710 00001381400200001 BIB 4 7 1381400200002 REACTION (14-SI-29(N,G)14-SI-30,,SPC,,SPA) 1381400200003 SAMPLE 150 mg of SiO2 enriched to over 99% in 29Si. 1381400200004 ERR-ANALYS (E-ERR) Uncertainties in gamma-ray energies; do not 1381400200005 include possible systematic errors estimated to 1381400200006 be 0.5 keV maximum at low energies and a maximum of 1381400200007 1.0 keV at high energies. 1381400200008 STATUS Data taken from Table 1 of reference. 1381400200009 ENDBIB 7 0 1381400200010 NOCOMMON 0 0 1381400200011 DATA 5 24 1381400200012 E E-ERR DATA ERR-S ERR-S 1381400200013 KEV KEV PC/REAC PC/REAC PER-CENT 1381400200014 2235.9 0.4 2.1 10. 1381400200015 2678.0 1.0 0.30 10. 1381400200016 3101.2 0.2 0.91 10. 1381400200017 3498.0 0.5 0.13 0.02 1381400200018 3738. 2. 0.05 0.02 1381400200019 3769.3 0.5 0.19 10. 1381400200020 3864.8 0.2 1.2 10. 1381400200021 3966.8 0.5 0.13 10. 1381400200022 4011.3 1.5 0.06 0.01 1381400200023 5127.9 0.8 0.08 0.01 1381400200024 5271.2 0.2 0.84 10. 1381400200025 6662.6 1.0 0.04 0.01 1381400200026 6744.2 0.3 1.33 10. 1381400200027 6821. 2. 0.04 0.01 1381400200028 6839.3 0.3 0.17 10. 1381400200029 7111.1 0.3 0.24 10. 1381400200030 7350.6 1.0 0.021 0.004 1381400200031 8374.5 2.0 0.027 0.007 1381400200032 8900. 2. 0.026 0.005 1381400200033 8954.4 2.0 0.006 0.003 1381400200034 9151.7 2.0 0.008 0.003 1381400200035 9619.6 1.0 0.036 10. 1381400200036 9791.7 1.0 0.041 10. 1381400200037 10608.0 0.4 0.26 10. 1381400200038 ENDDATA 26 0 1381400200039 ENDSUBENT 38 0 1381400299999 SUBENT 13814003 20010710 00001381400300001 BIB 4 7 1381400300002 REACTION (14-SI-30(N,G)14-SI-31,,SPC,,SPA) 1381400300003 SAMPLE 150 mg of SiO(2) enriched to over 99% in 30Si. 1381400300004 ERR-ANALYS (E-ERR) Uncertainties in gamma-ray energies; do not 1381400300005 include possible systematic errors estimated to 1381400300006 be 0.5 keV maximum at low energies and a maximum of 1381400300007 0.8 keV at high energies. 1381400300008 STATUS Data taken from Table 3 of reference. 1381400300009 ENDBIB 7 0 1381400300010 NOCOMMON 0 0 1381400300011 DATA 5 13 1381400300012 E E-ERR DATA ERR-S ERR-S 1381400300013 KEV KEV PC/REAC PC/REAC PER-CENT 1381400300014 753.0 1.0 1.1 0.2 1381400300015 1307. 2. 0.081 10. 1381400300016 1694.8 1.0 0.032 0.008 1381400300017 2206.9 0.6 0.11 0.04 1381400300018 2781.0 0.2 0.77 10. 1381400300019 3055.0 0.4 0.73 10. 1381400300020 3534.0 1.0 0.022 0.005 1381400300021 3630.2 0.3 0.076 10. 1381400300022 4259. 2. 0.004 0.002 1381400300023 4381.5 0.4 0.018 10. 1381400300024 4528.3 0.2 0.13 10. 1381400300025 5873.2 0.5 0.011 0.002 1381400300026 6588.7 0.4 0.018 10. 1381400300027 ENDDATA 15 0 1381400300028 ENDSUBENT 27 0 1381400399999 ENDENTRY 3 0 1381499999999