ENTRY 22803 20131117 22382280300000001 SUBENT 22803001 20131117 22382280300100001 BIB 18 131 2280300100002 TITLE Measurement of the Mo-nat(n,x)Nb-94 reaction cross 2280300100003 sections using ultra low-level gamma-ray spectrometry 2280300100004 at HADES 2280300100005 AUTHOR (P.Reimer, M.Hult, A.J.M.Plompen, P.N.Johnston, 2280300100006 V.Avrigeanu, S.M.Qaim) 2280300100007 INSTITUTE (2ZZZGEL) Reimer, Hult, Plompen, Johnston 2280300100008 (2GERJUL) Reimer, Qaim 2280300100009 (3AULAUL) Johnston, Royal Melbourne Institute of 2280300100010 Technology, Dept of Applied Physics 2280300100011 (3RUMBUC) Avrigeanu 2280300100012 REFERENCE (J,NP/A,705,(3-4),265,2002) Main reference, data given2280300100013 ((T,REIMER,20011013)=(R,JUEL-3986,20011013)) The 2280300100014 Manuscript of the Thesis. Full description of the 2280300100015 experiment and data Table. 2280300100016 (J,NSTS,2,(1),192,200208) 2280300100017 REL-REF (I,,A.Fessler+,J,NSE,134,171,2000) Experimental details2280300100018 (M,,J.F.Briesmeister,R,LA-13709-M,2002) Neutron 2280300100019 Spectrum evaluation with the help of Monte-Carlo 2280300100020 code (MCNP-4C) 2280300100021 FACILITY (VDG,2ZZZGEL) 7-MV Van de Graaff Accelerator, 2280300100022 Neutron Physics Unit, Institute For Reference 2280300100023 Materials and Measurements, Geel, Belgium. 2280300100024 Deuterium beam current is aprx 15 micro-A, 2280300100025 beam energy is 4 MeV . 2280300100026 INC-SOURCE (D-T) H-3(d,n)He-4. Deuterons incident on a metal 2280300100027 titanium-tritium target (1.923 mg/cm**2 thick) 2280300100028 on a silver backing (0.5 mm thick). This reaction 2280300100029 generated primary neutrons with energies in the range 2280300100030 13.4 to 20.6 MeV. Energy scale uncertainty is 5 keV. 2280300100031 INC-SPECT -Monte-Carlo code (MCNP-4C) was used to calculate 2280300100032 neutron spectrum and activity distribution 2280300100033 in the samples. 2280300100034 METHOD (ACTIV) cross sections were measured using the neutron 2280300100035 activation method. 2280300100036 (GSPEC) Ultra low-level gamma-ray spectrometry . 2280300100037 (STTA) Stack target irradiation . 2280300100038 DETECTOR (HPGE) For central sample activity measurement at the 2280300100039 earth surface. 2280300100040 (TELES,HPGE,HPGE) Several high purity germanium 2280300100041 detectors for side samples activity measurements 2280300100042 at the depth of 225 m . 2280300100043 (LONGC) Long counter working in multichannel scaling 2280300100044 mode - for neutron flux monitoring . 2280300100045 MONITOR 1(13-AL-27(N,A)11-NA-24,,SIG) Primary Standard Monit1 2280300100046 Used For Measurements with Neutron Energy Above 6 MeV2280300100047 2(13-AL-27(N,P)12-MG-27,,SIG) Secondary Standard. Monit22280300100048 3(27-CO-59(N,2N)27-CO-58,,SIG) Monit3 2280300100049 4(41-NB-93(N,2N)41-NB-92-M,,SIG) Monit4 Secondary Stand.2280300100050 All Measurements Involving Secondary Standards were 2280300100051 Eventually Referenced to the Primary Standards. 2280300100052 All Relative Measurements were Eventually Normalized 2280300100053 To the Primary Standards. 2280300100054 MONIT-REF 1(,H.Conde,R,INDC(SEC)-101,1992) (M0NIT1) Also H.Conde, 2280300100055 R,NEANDC-311"U",M.Wagner+,J.Physics Data,13-5,1990 2280300100056 2(,P.F.Rose+,R,ENDF-201,1991) (MONIT2) Evaluated 2280300100057 Nuclear Data File, ENDF/B-VI.6 2280300100058 3(,P.F.Rose+,R,ENDF-201,1991) (MONIT3) Evaluated 2280300100059 Nuclear Data File, ENDF/B-VI.1 . 2280300100060 4(,H.Conde,R,INDC(SEC)-101,1992) (MONIT4) See also 2280300100061 H,Conde,R,NEANDC-311/U,1992 , 2280300100062 M.Wagner+,R,INDC(AUS)-D14,199110 . 2280300100063 DECAY-MON 1(11-NA-24,14.9590HR,DG,1369.,1.0) Monit1 2280300100064 2(12-MG-27,9.458MIN,DG,843.76,0.718) Monit2 2280300100065 3(27-CO-58-G,70.86D,DG,810.78,0.9945) Monit3 2280300100066 4(41-NB-92-M,10.15D,DG,934.44,0.9907) Monit4 2280300100067 ANALYSIS -Cross-section ratios were derived from the gamma 2280300100068 ray analysis obtained during simultaneous irradiation 2280300100069 at different energies of different samples and 2280300100070 monitor foils using energy dependence of the monitor 2280300100071 reactions. 2280300100072 CORRECTION - Experimental data following application of various 2280300100073 corrections. Most of these correction procedures 2280300100074 were standard. The neutron scattering corrections 2280300100075 were derived by the Monte-Carlo method using the 2280300100076 computer code (MCNP-4C). The raw experimental data 2280300100077 were corrected for the following effects: 2280300100078 . Gamma-ray detection efficiency. 2280300100079 . Gamma-ray branching factors. 2280300100080 . Gamma-ray coincidence summing effects. 2280300100081 . Geometric effects. 2280300100082 . Gamma-ray absorption. 2280300100083 . Absorption and scattering of neutrons. 2280300100084 . Low-energy neutrons from the target. 2280300100085 . Decay of product nuclei. 2280300100086 . Fluctuations in neutron flux during the 2280300100087 irradiation period. 2280300100088 . Isotopic abundances. 2280300100089 . Multiple scattering of the neutrons in samples .2280300100090 ADD-RES (THEO) For all measurements nuclear model calculations2280300100091 were produced using models of the Hauser- 2280300100092 Feshbach type (HELGA, GNASH, EMPIRE, STAPRE, 2280300100093 STAPRE-H) . 2280300100094 ERR-ANALYS (ERR-T) Total Errors for the cross sections were 2280300100095 deduced by combining partial errors from 2280300100096 various sources in quadrature. Error sources 2280300100097 considered were: 2280300100098 (ERR-S,,25.) Max Statistical counting errors - 25% 2280300100099 (ERR-1,,3.) Max Uncertainty in detector 2280300100100 efficiencies - 3% 2280300100101 (ERR-2,,8.) Max Uncertainty in gamma-emission 2280300100102 probability - 8% 2280300100103 (ERR-3,,8.) Max Uncertainty in decay half lives - 8% 2280300100104 (ERR-4,,7.) Max Uncertainty in coincidence summing 2280300100105 corrections - 7% 2280300100106 (ERR-5,,3.) Max Uncertainty in the absorption of 2280300100107 gamma rays - 3% 2280300100108 (ERR-6,,1.) Max Uncertainty due to sample mass - 1% 2280300100109 (ERR-7,,1.) Max Uncertainty due to counting times - 1% 2280300100110 (ERR-8,,1.) Max Uncertainty due to cooling times - 1% 2280300100111 (ERR-9,,6.) Max Uncertainty due to gas-in/gas-out 2280300100112 background neutrons - 6% 2280300100113 (ERR-10,,16.) Max Uncertainty due to breakup 2280300100114 neutrons - 16% 2280300100115 (ERR-11,,12.) Max Uncertainty in Low-Energy Neutron 2280300100116 corrections - 12% 2280300100117 (ERR-12,,0.5) Max Uncertainty due to neutron flux 2280300100118 fluctuations - 0.5% 2280300100119 (ERR-13) Normalization uncertainty . 2280300100120 (ERR-14) Most frequently occurring uncertainty due to 2280300100121 reference cross section error . 2280300100122 (EN-ERR) Error in the Center of Neutron Energy Line . 2280300100123 HISTORY (20030502) J.O.S. 2280300100124 (20030502U) Last checking has been done. 2280300100125 (20090814A) M.M. Reference C,2001TSUKUBA was corrected.2280300100126 ERR-14 value was defined according to value given in 2280300100127 J,NP/A,705. 2280300100128 Maximal errors value were moved from COMMON block into2280300100129 ERR-ANALYS lines. ERR-1 -> ERR-S . 2280300100130 Errors numbers were renumbered. 2280300100131 (20131117U) SD: Ref. 2001TSUKUB deleted according to 2280300100132 MEMO CP-D/791. ERR-ANALYS updated. Minor corrections. 2280300100133 ENDBIB 131 0 2280300100134 COMMON 3 3 2280300100135 ERR-13 ERR-14 EN-RSL 2280300100136 PER-CENT PER-CENT KEV 2280300100137 8. 3. 5. 2280300100138 ENDCOMMON 3 0 2280300100139 ENDSUBENT 138 0 2280300199999 SUBENT 22803002 20090814 22142280300200001 BIB 4 16 2280300200002 REACTION (42-MO-0(N,X)41-NB-94,,SIG) Sum of the Mo-94(N,P) and 2280300200003 Mo-95(N,N+P) reactions 2280300200004 SAMPLE 2 mm thick sample was used to allow measurement of low2280300200005 activity of the reaction product. Samples were squares2280300200006 24 mm side-length and 2mm thickness, and disks of 50mm2280300200007 diameter and up to 14 mm thickness . 2280300200008 Total mass of all samples was 1482.2 ( 290.8, 596.2, 2280300200009 595.2 ) gram arranged around the neutron source 2280300200010 in a special geometry consisting of one central and 2280300200011 two side samples. 2280300200012 Samples are of natural isotopic abundance. Isotopes 2280300200013 in question were of following quantity - 2280300200014 Mo-94 content is 9.25%, 2280300200015 Mo-95 content is 15.92% 2280300200016 DECAY-DATA (41-NB-94,20300.YR,DG,871.1,0.999) 2280300200017 STATUS (TABLE) From Table 5 of J,NP/A,705,(3-4),265,2002. 2280300200018 ENDBIB 16 0 2280300200019 NOCOMMON 0 0 2280300200020 DATA 4 3 2280300200021 EN EN-ERR DATA ERR-T 2280300200022 MEV MEV MB MB 2280300200023 14.5 0.7 9.9 1.6 2280300200024 18.0 0.7 17.6 1.4 2280300200025 20.3 0.3 28.3 7.3 2280300200026 ENDDATA 5 0 2280300200027 ENDSUBENT 26 0 2280300299999 ENDENTRY 2 0 2280399999999