ENTRY 23100 20130203 22342310000000001 SUBENT 23100001 20130203 22342310000100001 BIB 20 136 2310000100002 TITLE Emission probabilities of gamma-rays from Np-238 and 2310000100003 their use for determination of the thermal neutron 2310000100004 capture cross section of Np-237 2310000100005 AUTHOR (A.Letourneau, F.Marie, P.Mutti, I.AlMahamid) 2310000100006 INSTITUTE (2FR SAC) A.Letourneau, F.Marie. 2310000100007 (2FR ILL) P.Mutti. 2310000100008 (1USABRK) I.AlMahamid. 2310000100009 REFERENCE (J,ARI,68,432,2010) 2310000100010 #doi:10.1016/j.apradiso.2009.11.038 2310000100011 REL-REF (I,22924001,F.Marie+,J,NIM/A,556,547,2006) 2310000100012 Exp. setup and method of analysis details. 2310000100013 MCNP code for simulation of HFR reactor. 2310000100014 (R,,B.Singh+,J,NDS,105,109,2005) 2310000100015 (R,,F.E.Chukreev+,J,NDS,97,129,2002) 2310000100016 (R,,J.K.Tuli+,J,NDS,100,347,2003) 2310000100017 FACILITY (REAC,2FR ILL) High flux reactor of Laue-Langevin 2310000100018 Institute in Grenoble. 2310000100019 MINI-INCA chamber. 2310000100020 INC-SOURCE (REAC) H9 irradiation channel allows for 4-PI 2310000100021 irradiation geometry. 2310000100022 INC-SPECT Highly thermalized neutron flux. Estimated epithermal 2310000100023 to thermal ratio of 0.0021 in Westcott convention. 2310000100024 Neutron density was quite constant in irradiation area.2310000100025 Deduced neutron flux (6.57+-0.15)*10**14 n/cm**2/s, 2310000100026 main uncertainty is attributed to the uncertainty of 2310000100027 initial quantity of Co-59 (=<2%). 2310000100028 PART-DET (G,A) 2310000100029 SAMPLE (93-NP-237,ENR=0.997574) Np-237 sample was 2310000100030 electrodeposited by molecular plating 2310000100031 technique on 12 mm diameter Ni foil of 4 microm 2310000100032 thickness in Lawrence Berkeley National Lab. Deposit 2310000100033 area - circle of 6 mm diameter. Mounted on Ti holder 2310000100034 together with 6 mm diameter Al foil containing 1% (in 2310000100035 mass) of Co-59 for neutron flux measurement. Distance 2310000100036 between Np-237 target and Co-59 monitor - 35 mm. 2310000100037 backing, irradiated 2 hours in H9 channel. 2310000100038 Isotopic composition of Np-237 sample: 2310000100039 Np-237 - 99.7574 %, Pu-238 - 0.00135 %, 2310000100040 Pu-239 - 0.1218 %, Pu-240 - 0.10635 %, 2310000100041 Cm-243 - 0.0083 %, Cm-244 - 0.0048 %. 2310000100042 Np-237 activity (370.3 +- 3.7) Bq was determined 2310000100043 relative to Cm-244 calibration source from 2310000100044 Radioactivity Standards Lab. of CERCA; the activity 2310000100045 was certified to be known with one-sigma 2310000100046 uncertainty of 0.7% for Cm-244 alpha-source. 2310000100047 Using nuclear parameters the number of Np-237 atoms was2310000100048 deduced to be (3.612+-0.036)*10**6 corresponding 2310000100049 to mass of (14.21+- 0.14) microg. 2310000100050 Np-237 and Co-59 samples were irradiated for 2.733 h in2310000100051 so-called diaphragm position of Lohengrin spectrometer 2310000100052 (H9 channel) 2310000100053 DECAY-DATA (93-NP-237,2.144E+6YR,A,4771.4,0.2315,A,4788.0,0.4764) 2310000100054 Alphas: 4771.4 +- 0.8 keV - 0.2315+- 0.29, 2310000100055 4788.0 +- 0.9 keV - 0.4764 +- 0.06; 2310000100056 gamma: 984.45 +- 0.02 keV, 2310000100057 HL=(2.144+-0.007)*10**6 year - 2310000100058 data from REL-REF B.Singh+. 2310000100059 From REL-REF of F.E.Chukreev+: 2310000100060 DETECTOR (SPEC,HPGE,IMPSI) Lohengrin mass spectrometer,equipped 2310000100061 with high purity germanium detector with intrinsic 2310000100062 efficiency of 9.98 %, energy resolution of 1.7 keV at 2310000100063 1173 keV; passive implanted planar silicon detector 2310000100064 with energy resolution 17 keV for 5.5 MeV alpha-rays. 2310000100065 METHOD (ASPEC) Composition of Np-237 sample and quantity of 2310000100066 Np-237 atoms were determined by alpha-spectroscopy 2310000100067 prior to irradiation by using Mini-INCA chamber. 2310000100068 (GSPEC) Alpha- and gamma- spectroscopy to analyze 2310000100069 samples after about half an hour after irradiation. 2310000100070 Measurements were made 2-3 days after the end of 2310000100071 irradiation. 2310000100072 ANALYSIS The photopeak activities were determined from 2310000100073 multi-peak chi-square minimization procedure, each 2310000100074 peak being modeled by Gaussian function added to an 2310000100075 exponential background. Final errors of gamma 2310000100076 activities contained the errors of fit and errors on 2310000100077 photopeak efficiency. 2310000100078 Measured activities/+-error: 2310000100079 Cooling time(days) 2310000100080 2.4037 2.5709 2.7381 2.9049 2310000100081 Np-237,Bq 371.2/3.6 367.5/3.4 367.4/3.4 387./5. 2310000100082 Pu-238,Bq 4890./83. 5184./85. 5263./85. 5387./129. 2310000100083 Np-238,Bq: 2310000100084 984.45keV 15.31/0.36 14.44/0.34 13.67/0.32 13.06/0.36 2310000100085 1025.87keV 5.32/0.21 5.05/0.20 4.72/0.19 4.54/0.26 2310000100086 1028.54keV 11.25/0.34 10.62/0.32 9.99/0.31 9.61/0.39 2310000100087 Absolute gamma-ray emission probabilities from Np-238 2310000100088 were determined in reference to the measured 2310000100089 alpha-activities of Pu-238. 2310000100090 Ratio of measured gamma-activities of Np-238 over the 2310000100091 alpha-activity of Pu-238 was used to deduce gamma-ray 2310000100092 intensities by fitting 2310000100093 MONITOR ((MONIT)27-CO-59(N,G)27-CO-60,,SIG) Effective c-s. 2310000100094 Neutron flux was measured by means of standard 2310000100095 Co-59(n,gamma)Co-60 reaction. Effective capture c-s 2310000100096 was evaluated by means of precise simulation of HFR 2310000100097 reactor with MCNP code using value of S.Mughabghab+ 2310000100098 for 0.0253 eV capture c-s of Co-59 (see ASSUMED). 2310000100099 ASSUMED (ASSUM1,27-CO-59(N,G)27-CO-60,,SIG,,MXW) 2310000100100 Value from REL-REF of Mughabghab,2006 at 0.0253 eV. 2310000100101 DECAY-MON (27-CO-60-G,1925.1D,DG,1173.237,0.999736, 2310000100102 DG,1332.501,0.999856) 2310000100103 HL=1925.1+-0.5 day. 2310000100104 Gamma: 1173.237 keV - 0.999736+-0.0007, 2310000100105 1332.501 keV - 0.999856+-0.0004 . 2310000100106 From REL-REF of J.K.Tuli+. 2310000100107 Gamma-activities at 1173.2 and 1332.5 keV were measured2310000100108 after irradiation giving an activity for Co-60 of 2310000100109 (6.00+-0.06)*10**5 Bq . 2310000100110 ERR-ANALYS (ERR-T) Total error includes 2310000100111 (ERR-1,,1.) Error on the decay rates. 2310000100112 (ERR-2) Error on the alpha-ray efficiency and modeling 2310000100113 of alpha-peak. 2310000100114 (ERR-S,,1.) Statistical error on the alpha-ray 2310000100115 measurement of Pu-238. 2310000100116 (ERR-4,,0.3) Error on emission probability of 2310000100117 alpha-rays from Pu-238. 2310000100118 (ERR-5) Error on gamma-ray photopeak efficiency. 2310000100119 (ERR-6,1.,3.) Error on the gamma-ray measurement of 2310000100120 Np-238 (including the statistical errors). 2310000100121 (ERR-9) Error on the neutron flux. 2310000100122 (ERR-10) Error on the initial quantity of Np-237 atoms.2310000100123 Maximal dead time uncertainty -1.%. 2310000100124 Maximal uncertainty of initial quantity of Co-59, 2310000100125 included in neutron flux error, -2.% 2310000100126 Error on combustion cross section of Np-238 2310000100127 (negligible in this case) - 16%. 2310000100128 CORRECTION For counts lost - correction factor applied for three 2310000100129 main Np-238 gamma-rays was (5+- 1) % . 2310000100130 HISTORY (20100327C) M.M. 2310000100131 (20110204U) SD: DOI was corrected. 2310000100132 Code ERR-7 (Error on combustion ...) deleted. 2310000100133 (20120120A) NDS(VZ): REL-REF: ND/B->NDS 2310000100134 (20130203A) SD: Small correction in SAMPLE. SF8=MXW was2310000100135 changed on SPA from REACTION code in Subent 002. 2310000100136 Title of the journal in REL-REF of Subent 003 was 2310000100137 changed (INC -> JIN). 2310000100138 ENDBIB 136 0 2310000100139 COMMON 8 6 2310000100140 MONIT MONIT-ERR ASSUM1 ASSUM1-ERR ERR-2 ERR-5 2310000100141 ERR-9 ERR-10 2310000100142 B B B B PER-CENT PER-CENT 2310000100143 PER-CENT PER-CENT 2310000100144 31.1 0.9 37.18 0.06 1. 2. 2310000100145 2.2 1.1 2310000100146 ENDCOMMON 6 0 2310000100147 ENDSUBENT 146 0 2310000199999 SUBENT 23100002 20130203 22342310000200001 BIB 7 26 2310000200002 REACTION (93-NP-237(N,G)93-NP-238,,SIG,,SPA) 2310000200003 DECAY-DATA (93-NP-238,2.117D,DG,984.45,0.256, 2310000200004 DG,1025.87,0.089, 2310000200005 DG,1028.54,0.188) 2310000200006 Gamma-ray intensities were measure in this experiment:2310000200007 0.256+-0.004, 0.089+-0.002, 0.188+-0.003 . 2310000200008 (94-PU-238,87.7YR,A,5456.3,0.2898,A,5499.03,0.7091) 2310000200009 HL=87.7+-0.3 year, 2310000200010 Alphas: 5456.3+-0.3 keV - 0.2898+-0.10, 2310000200011 5499.03+-0.20 keV - 0.7091+-0.10 . 2310000200012 ANALYSIS Effective cross sections were deduced from Np-238 2310000200013 activity measurement and from Pu-238 activity 2310000200014 measurement, resulting in effective cross-section. 2310000200015 Present value was compared to the effective c-s 2310000200016 calculated by MCNP simulation - JEFF-3.1 and ENDF/B-VI 2310000200017 are in good agreement, JENDL is lower about 11 %. 2310000200018 FLAG (1.) From Np-238 activity 2310000200019 (2.) From Pu-238 activity 2310000200020 (3.) Resulting value. 2310000200021 COMMENT From Dr.A.Letourneau: REACTION MXW -> SPA (H9 ch of 2310000200022 ILL is only 98% thermalized) 2310000200023 STATUS (TABLE) Table 5 of J,ARI,68,432,2010 and 2310000200024 text, page 437. 2310000200025 (COREL,22941031) In 22941 - prelim. publications. 2310000200026 HISTORY (20130203A) SD: SF8=MXW was changed on SPA from 2310000200027 REACTION code in Subent 002. 2310000200028 ENDBIB 26 0 2310000200029 COMMON 1 3 2310000200030 EN-DUMMY 2310000200031 EV 2310000200032 0.0253 2310000200033 ENDCOMMON 3 0 2310000200034 DATA 3 3 2310000200035 DATA ERR-T FLAG 2310000200036 B B NO-DIM 2310000200037 149.9 3.7 1. 2310000200038 150.3 3.7 2. 2310000200039 150.1 3.7 3. 2310000200040 ENDDATA 5 0 2310000200041 ENDSUBENT 40 0 2310000299999 SUBENT 23100003 20130203 22342310000300001 BIB 6 28 2310000300002 REACTION (93-NP-237(N,G)93-NP-238,,SIG,,,DERIV) 2310000300003 ANALYSIS 25.3 meV value was extracted from measured effective 2310000300004 cross section using the ratio of 25.3 meV c-s to 2310000300005 effective cross, calculated from data bases JEFF-3.1 2310000300006 and ENDF/B-VI (see ASSUM2). 2310000300007 ASSUMED (ASSUM2,(93-NP-237(N,G)93-NP-238,,SIG,,MXW)/ 2310000300008 (93-NP-237(N,G)93-NP-238,,SIG)) 2310000300009 REL-REF (A,23100003,F.Brown+,J,JIN,2,205,1956) 2310000300010 (A,12487005,M.S.Smith+,J,PR,107,525,1957) 2310000300011 (A,23109001,S.H.Eberle+,R,KFK-1456,51,1971) 2310000300012 (A,40579007,L.N.Jurova+,J,YK,1984,(1/55),3,1984) 2310000300013 (A,22366002,K.Kobayashi+,J,NST,31,1239,1994) Agree 2310000300014 after additional correction. 2310000300015 (A,10877002,L.W.Weston+,J,NSE,79,184,1981) 2310000300016 (A,,R.P.Schuman+,R,IN-1296,1969) 2310000300017 (D,20638070,R.B.Tattersall+,J,JNE/A,12,32,1960) 2310000300018 (D,22977003,H.Harada+,J,NST,43,1289,2006) 2310000300019 (D,22835002,T.Katoh+,J,NST,40,559,2003) 2310000300020 (R,,S.F.Mughabghab,B,NEUT.RES,,2006) Ref. for ASSUM. 2310000300021 STATUS (TABLE) Table 5 of J,ARI,68,432,2010. 2310000300022 (DEP,23100002) Derived from Subent 002 using mean ratio2310000300023 value. 2310000300024 (COREL,22941032) In 22941 - prelim. publications. 2310000300025 HISTORY (20100327C) M.M. 2310000300026 (20110204U) SD: DOI was corrected. 2310000300027 Code ERR-7 (Error on combustion ...) deleted. 2310000300028 (20130203A) SD: Title of the journal in REL-REF was 2310000300029 changed (INC -> JIN). 2310000300030 ENDBIB 28 0 2310000300031 NOCOMMON 0 0 2310000300032 DATA 5 1 2310000300033 EN DATA ERR-T ASSUM2 ASSUM2-ERR 2310000300034 EV B B NO-DIM NO-DIM 2310000300035 0.0253 182.2 4.5 0.824 0.003 2310000300036 ENDDATA 3 0 2310000300037 ENDSUBENT 36 0 2310000399999 ENDENTRY 3 0 2310099999999