ENTRY 31511 20160929 31753151100000001 SUBENT 31511001 20160929 31753151100100001 BIB 16 69 3151100100002 INSTITUTE (3ARGCAB) 3151100100003 REFERENCE (J,JRN,241,25,1999)Data are given 3151100100004 (J,RCA,78,11,1997) Some details of method are given 3151100100005 (J,NSE,127,245,1997) Details of the activity 3151100100006 measurements, the calculations of cross sections and 3151100100007 the evaluation of systematic uncertainties are given. 3151100100008 They are coded under INC-SPECT, DETECTOR, MONITOR and 3151100100009 DECAY-MON 3151100100010 AUTHOR (M.A.Arribere,S.Ribeiro Guevara,A.J.Kestelman, 3151100100011 I.M.Cohen) 3151100100012 TITLE Determination of the fission averaged cross sections 3151100100013 of some threshold reactions induced on chlorine, 3151100100014 potassium and calcium, and their role in the 3151100100015 development of self-validated methods of neutron 3151100100016 activation analysis 3151100100017 METHOD (ACTIV) Activation method with registration of 3151100100018 secondary gamma-ray spectra. 3151100100019 FACILITY (REAC,3ARGCAB) 3151100100020 INC-SOURCE (REAC) Neutrons from RA-6 materials test reactor 3151100100021 at Centre Atomico Barilochi with thermal neutron flux 3151100100022 about 6.0E+12 neutrons/cm**2/sec, epithermal neutron 3151100100023 flux about 3.0E+11 neutrons/cm**2/sec and fast neutron 3151100100024 flux about 2.0E+12 neutrons/cm**2/sec 3151100100025 INC-SPECT Undisturbed U-235 fission spectrum. Set of 8 3151100100026 activation detectors having thresholds from 2.6 to 3151100100027 11.6 MeV were used to show that flux of fission 3151100100028 neutrons is undisturbed 3151100100029 DETECTOR (HPGE) 67 cm*3 ORTEC high-purity germanium intrinsic-N 3151100100030 coaxial detector with resolution 2 keV at 1.33 MeV. 3151100100031 The detector absolute efficiency curve was obtained 3151100100032 with IAEA standard sources (Am-241, Ba-133, Co-60, 3151100100033 Cs-137, Eu-152) calibrated within 2 per-cent 3151100100034 uncertainty. Ra-226 source was also used 3151100100035 SAMPLE High purity chemical samples with approximate masses 3151100100036 NaCl - 250 mg, KH2PO4 - 150 mg, K2HPO4 - 150 mg and 3151100100037 CaCO3 - 150 mg, dried at 80C deg and kept in a 3151100100038 desiccator up to a moment of irradiation 3151100100039 MONITOR (28-NI-58(N,P)27-CO-58,,SIG,,FIS) Data are taken 3151100100040 from J.H. Baard, W.L. Zijp and H. Nolthenius, Nuclear 3151100100041 Data Guide for Reactor Neutron Metrology, Kluwer 3151100100042 Academic Publishers, Dordrecht, The Netherlands, 1989 3151100100043 DECAY-MON (27-CO-58-G,70.82D,DG,810.772,.9944) Data are taken 3151100100044 from J.H. Baard, W.L. Zijp and H. Nolthenius, Nuclear 3151100100045 Data Guide for Reactor Neutron Metrology, Kluwer 3151100100046 Academic Publishers, Dordrecht, The Netherlands, 1989 3151100100047 CORRECTION Gamma self-attenuation factor for 811.79 keV line in 3151100100048 nickel foil and wire was calculated as 0.992 3151100100049 and 0.981, respectively. 3151100100050 ERR-ANALYS (ERR-T) The total uncertainty was determined by 3151100100051 propagation of the following partial uncertainties. 3151100100052 (ERR-S) The statistical component was obtained as 3151100100053 weighed averaged for few measurements. 3151100100054 (MONIT-ERR) reference cross section ( 2.8% ) 3151100100055 (ERR-1,2.,3.) 2 to 3% - uncertainty in the detector 3151100100056 absolute efficiency determination 3151100100057 - other systematic uncertainties 3151100100058 COMMENT The feasibility of use of 17-Cl-37(n,p)16-S-37 reaction3151100100059 in epicadmium neutron spectra for determination 3151100100060 of chlorine in neutron activation analysis without 3151100100061 interference from 16-S-36(n,g)16-S-37 reaction is 3151100100062 given. 19-K-41(n,a)17-Cl-38 reaction can be used only 3151100100063 for potassium determination in the samples having high 3151100100064 K to Cl ratio. For this the irradiation with and 3151100100065 without cadmium cover should be performed. None of the 3151100100066 reactions studied offer the possibility for calcium 3151100100067 assay, except in some very particular case. 3151100100068 HISTORY (20010315C) Compiled by VP 3151100100069 (20160922U) VS. SF4 in MONITOR corrected. 3151100100070 Coded info in ERR-ANALYS added. 3151100100071 ENDBIB 69 0 3151100100072 COMMON 3 3 3151100100073 KT-DUMMY MONIT MONIT-ERR 3151100100074 MEV MB MB 3151100100075 1.32 111. 3. 3151100100076 ENDCOMMON 3 0 3151100100077 ENDSUBENT 76 0 3151100199999 SUBENT 31511002 20010315 00003151100200001 BIB 5 13 3151100200002 REACTION (17-CL-37(N,P)16-S-37,,SIG,,FIS) 3151100200003 METHOD Cadmium cover was used to reduce activity 3151100200004 from 17-CL-37(N,G) reaction 3151100200005 DECAY-DATA (16-S-37,5.05MIN,DG,3103.36,.940) 3151100200006 ANALYSIS The influence of the competitive reactions 3151100200007 16-S-36(n,g)16-S-37 and 18-AR-40(n,a)16-S-37 in the 3151100200008 sample was shown to be negligible. Cross section value 3151100200009 was obtained as weighted averaged of results of 4 3151100200010 measurements with their statistical uncertainties 3151100200011 (0.237+-0.018, 0.226+-0.014, 0.235+-0.018 and 3151100200012 0.245+-0.021 mb).Then systematic uncertainty was 3151100200013 added 3151100200014 ERR-ANALYS Statistical and total uncertainties are given 3151100200015 ENDBIB 13 0 3151100200016 NOCOMMON 0 0 3151100200017 DATA 3 1 3151100200018 DATA ERR-S ERR-T 3151100200019 MB MB MB 3151100200020 0.234 0.0086 0.015 3151100200021 ENDDATA 3 0 3151100200022 ENDSUBENT 21 0 3151100299999 SUBENT 31511003 20010315 00003151100300001 BIB 6 19 3151100300002 REACTION (19-K-41(N,A)17-CL-38,,SIG,,FIS) 3151100300003 METHOD Cadmium cover was used to reduce interference 3151100300004 from the 17-CL-37(N,G)17-CL-38 reaction due to 3151100300005 impurity of chlorine in the sample 3151100300006 DECAY-DATA (17-CL-38,37.24MIN,DG,1642.71,0.319) 3151100300007 (17-CL-38,37.24MIN,DG,2167.41,0.424) 3151100300008 ANALYSIS The interference from 19-K-39(n,2n)19-K-38 reaction 3151100300009 leading to the same decay gamma in 18-AR-38 after beta+3151100300010 decay (T1/2=7.63MIN) was reduced by time exposure 3151100300011 before the activity measurements. Cross section value 3151100300012 was obtained as weighted averaged of results of 6 3151100300013 measurements (3 for KH2PO4 and 3 for K2HPO4) with their3151100300014 statistical uncertainties 3151100300015 (0.742+-0.170, 0.744+-0.120, 0.806+-0.120, 3151100300016 0.750+-0.062, 0.717+-0.040 and 0.752+-0.043 mb). 3151100300017 Then systematic uncertainty was added. 3151100300018 ERR-ANALYS Statistical and total uncertainties are given 3151100300019 CORRECTION Corrections due to chlorine impurities for cadmium 3151100300020 shielded potassium samples was less than 1% 3151100300021 ENDBIB 19 0 3151100300022 NOCOMMON 0 0 3151100300023 DATA 3 1 3151100300024 DATA ERR-S ERR-T 3151100300025 MB MB MB 3151100300026 0.740 0.025 0.044 3151100300027 ENDDATA 3 0 3151100300028 ENDSUBENT 27 0 3151100399999 SUBENT 31511004 20010315 00003151100400001 BIB 5 12 3151100400002 REACTION (20-CA-42(N,P)19-K-42,,SIG,,FIS) 3151100400003 METHOD Cadmium cover was used to reduce interference 3151100400004 from (n,g) reaction on possible potassium 3151100400005 impurities in the sample 3151100400006 DECAY-DATA (19-K-42,12.360HR,DG,1524.70,0.1808) 3151100400007 ANALYSIS The interference from 21-SC-45(n,a)19-K-42 reaction 3151100400008 due to impurity in the calcium sample was not detected.3151100400009 Cross section value was obtained as weighted averaged 3151100400010 of results of 3 measurements with their statistical 3151100400011 uncertainties (3.03+-0.11, 2.98+-0.10 and 3.35+-0.13 3151100400012 mb).Then systematic uncertainty was added 3151100400013 ERR-ANALYS Statistical and total uncertainties are given 3151100400014 ENDBIB 12 0 3151100400015 NOCOMMON 0 0 3151100400016 DATA 3 1 3151100400017 DATA ERR-S ERR-T 3151100400018 MB MB MB 3151100400019 3.09 0.11 0.22 3151100400020 ENDDATA 3 0 3151100400021 ENDSUBENT 20 0 3151100499999 SUBENT 31511005 20010315 00003151100500001 BIB 5 16 3151100500002 REACTION (20-CA-43(N,P)19-K-43,,SIG,,FIS) 3151100500003 METHOD Measurements were done with cadmium covered sample 3151100500004 DECAY-DATA (19-K-43,22.3HR,DG,372.76,0.8680) 3151100500005 (19-K-43,22.3HR,DG,396.86,0.1185) 3151100500006 (19-K-43,22.3HR,DG,593.39,0.1126) 3151100500007 (19-K-43,22.3HR,DG,617.49,0.792) 3151100500008 ANALYSIS The evaluated contribution of 3151100500009 20-CA-46(n,a)18-AR-43 ->(beta-)->19-K-43 to the total 3151100500010 activity of 19-K-43 under given conditions of 3151100500011 measurements was less than 1.0E-5%. 3151100500012 Final value is obtained as weighted averaged 3151100500013 of results of 4 measurements with their statistical 3151100500014 uncertainties (3.5+-1.2, 2.201+-0.091, 2.283+-0.094 and3151100500015 2.306+-0.086 mb). Then systematic uncertainty was 3151100500016 added 3151100500017 ERR-ANALYS Statistical and total uncertainties are given 3151100500018 ENDBIB 16 0 3151100500019 NOCOMMON 0 0 3151100500020 DATA 3 1 3151100500021 DATA ERR-S ERR-T 3151100500022 MB MB MB 3151100500023 2.27 0.052 0.12 3151100500024 ENDDATA 3 0 3151100500025 ENDSUBENT 24 0 3151100599999 SUBENT 31511006 20010315 00003151100600001 BIB 5 9 3151100600002 REACTION (20-CA-44(N,P)19-K-44,,SIG,,FIS) 3151100600003 METHOD Measurements were done with cadmium covered sample 3151100600004 DECAY-DATA (19-K-44,22.13MIN,DG,1157.03,0.58) 3151100600005 ANALYSIS Final value is obtained as weighted averaged 3151100600006 of results of 4 measurements with their statistical 3151100600007 uncertainties (0.084+-0.013, 0.0717+-0.0068, 3151100600008 0.0774+-0.0073 and 0.067+-0.012 mb). Then systematic 3151100600009 uncertainty was added 3151100600010 ERR-ANALYS Statistical and total uncertainties are given 3151100600011 ENDBIB 9 0 3151100600012 NOCOMMON 0 0 3151100600013 DATA 3 1 3151100600014 DATA ERR-S ERR-T 3151100600015 MB MB MB 3151100600016 0.074 0.0044 0.013 3151100600017 ENDDATA 3 0 3151100600018 ENDSUBENT 17 0 3151100699999 ENDENTRY 6 0 3151199999999