ENTRY 23236 20140607 22392323600000001 SUBENT 23236001 20140607 22392323600100001 BIB 12 42 2323600100002 REFERENCE (J,JRN,300,599,2014) 2323600100003 #doi:10.1007/s10967-014-3068-3 2323600100004 AUTHOR (L.Sneyers,P.Vermaercke) 2323600100005 TITLE Determination of Q0 and k0 factors for 75Se. 2323600100006 INSTITUTE (2BLGMOL) L.Sneyers,P.Vermaercke. 2323600100007 FACILITY (REAC,2BLGMOL) Irradiation channels S84, Y4 and X26 of 2323600100008 the BR1 reactor at SCK*CEN, Belgium, were used . 2323600100009 INC-SOURCE (REAC) 2323600100010 INC-SPECT Parameters of the neutron spectra: 2323600100011 Channel f a 2323600100012 S84 17.0 -0.003 2323600100013 Y4 38.7 0.066 2323600100014 X26 95.0 0.11 2323600100015 f - ratio of the thermal neutron flux to epithermal 2323600100016 flux, 2323600100017 a - slope parameter of the epithermal spectrum. 2323600100018 METHOD (ACTIV) Each of the materials were irradiated in 2323600100019 three different channels of the BR1 reactor, both under2323600100020 a 1 mm thick Cd cover and bare, always accompanied by a2323600100021 IRMM-530 flux monitor. 2323600100022 DETECTOR (HPGE) After irradiation and appropriate cooling time, 2323600100023 samples were measured on five HPGe detectors Obelix, 2323600100024 Panoramix,Calvin, Asterix or Hobbes (efficiency ranging2323600100025 between 40 and 55 %). 2323600100026 ANALYSIS The Hyperlab program was used for net peak area 2323600100027 evaluation. 2323600100028 The value f (thermal-epithermal flux ratio) was 2323600100029 determined for each channel using the Cd ratio method, 2323600100030 measuring the Au-monitor, bare and Cd-covered, at the 2323600100031 same position on the same detectors as the Se-samples. 2323600100032 CORRECTION - Coincidence correction. 2323600100033 Coincidence correction factors for a Se-shot measured 2323600100034 at 25 cm detector distance: 2323600100035 E-gamma (keV) COI factor 2323600100036 121.1 0.996 2323600100037 136.0 0.996 2323600100038 264.7 0.997 2323600100039 279.5 0.998 2323600100040 400.7 1.011 2323600100041 - Epithermal and thermal self-shielding corrections 2323600100042 were calculated using the MATSFF program. 2323600100043 HISTORY (20140607C) M.M. 2323600100044 ENDBIB 42 0 2323600100045 NOCOMMON 0 0 2323600100046 ENDSUBENT 45 0 2323600199999 SUBENT 23236002 20140607 22392323600200001 BIB 10 48 2323600200002 REACTION ((34-SE-74(N,G)34-SE-75,,RI)// 2323600200003 (34-SE-74(N,G)34-SE-75,,SIG)) 2323600200004 Q0 value (ratio of resonance integral to thermal 2323600200005 neutron activation cross-section) 2323600200006 SAMPLE Three different materials: 2323600200007 - a pure Se shots standard, Manufacturer Alfa Aesar, 2323600200008 Puratronic, typical weight Se 5 mg, concentration 2323600200009 99.999% pure; 2323600200010 - pure Se powder, Manufacturer Alfa Aesar, typical 2323600200011 weight Se 5 mg, concentration 99.999% pure; 2323600200012 -an ICP standard solution , Manufacturer NIST 3149a, 2323600200013 typical weight Se 0.1 mg, concentration 1,000 ppm . 2323600200014 Samples were packed in plastic bags and spacers were 2323600200015 used to create a minimum 2 cm distance between the 2323600200016 different samples during irradiations. 2323600200017 DECAY-DATA (34-SE-75,119.8D) 2323600200018 METHOD - k0 and Q0 values were determined by bare monitor 2323600200019 method. 2323600200020 - k0, Q0 and FCd were determined by Cd-covered methods.2323600200021 ANALYSIS The effective mean resonance energy Er needed to 2323600200022 convert the measured Q0(a) to Q0 was 29.05 eV as 2323600200023 calculated A.Trkov (2013, private communication). 2323600200024 In our calculations the impact of taking Er equal to 2323600200025 29.4 eV (from REL-REF of F.De Corte+) was < 0.1 %. 2323600200026 REL-REF (R,,F.De Corte+,J,AND,85,47,2003) 2323600200027 ERR-ANALYS (DATA-ERR) Absolute uncertainties are expanded 2323600200028 uncertainties expressed at a 95 % confidence interval 2323600200029 with a coverage factor k = 2. 2323600200030 FLAG (1.) Cd-ratio method, Se-short sample 2323600200031 (2.) Cd-ratio method, Se-powder 2323600200032 (3.) Cd-ratio method, Se-ISP 2323600200033 (4.) Bare method, Se-short sample 2323600200034 (5.) Bare method, Se-powder 2323600200035 ADD-RES Measured k0-values: 2323600200036 E-gamma Se-powder Se-shot 2323600200037 keV Bare Cdsubtracted Bare Cdsubtracted 2323600200038 121.1 0.00223 0.00216 0.00220 0.00221 2323600200039 136.0 0.00744 0.00747 0.00755 0.00755 2323600200040 264.7 0.00763 0.00758 0.00775 0.00765 2323600200041 279.5 0.00319 0.00322 0.00322 0.00322 2323600200042 400.7 0.00145 0.00147 0.00146 0.00146 2323600200043 The value for FCd which gave the best matching results 2323600200044 for k0 was 0.89 +-0.03 (the given uncertainty is the 2323600200045 expanded uncertainty expressed at a 95 % confidence 2323600200046 interval with k = 2). The assumption that FCd was equal2323600200047 to unity would have led to k0-factors about 3 % higher 2323600200048 in calculations. 2323600200049 STATUS (TABLE) Table 7 of J,JRN,300,599,2014. 2323600200050 ENDBIB 48 0 2323600200051 COMMON 2 3 2323600200052 EN-MIN-NM EN-MEAN-DN 2323600200053 EV EV 2323600200054 0.5 0.0253 2323600200055 ENDCOMMON 3 0 2323600200056 DATA 3 5 2323600200057 DATA DATA-ERR FLAG 2323600200058 NO-DIM NO-DIM NO-DIM 2323600200059 11.5 0.4 1. 2323600200060 11.0 0.4 2. 2323600200061 11.1 0.4 3. 2323600200062 11.6 0.5 4. 2323600200063 10.4 0.5 5. 2323600200064 ENDDATA 7 0 2323600200065 ENDSUBENT 64 0 2323600299999 SUBENT 23236003 20140607 22392323600300001 BIB 6 36 2323600300002 REACTION ((34-SE-74(N,G)34-SE-75,,RI)// 2323600300003 (34-SE-74(N,G)34-SE-75,,SIG)) 2323600300004 Q0 value (ratio of resonance integral to thermal 2323600300005 neutron activation cross-section) 2323600300006 ANALYSIS Averaged for all samples and two methods. 2323600300007 ERR-ANALYS (DATA-ERR) Absolute uncertainties are expanded 2323600300008 uncertainties expressed at a 95 % confidence interval 2323600300009 with a coverage factor k = 2. 2323600300010 ADD-RES E-gamma,keV Measured k0-values 2323600300011 121.1 0.00220 +- 0.00004 2323600300012 136.0 0.00750 +- 0.00015 2323600300013 264.7 0.00765 +- 0.00015 2323600300014 279.5 0.00321 +- 0.00006 2323600300015 400.7 0.00146 +- 0.00003 2323600300016 The uncertainty given is a propagated uncertainty 2323600300017 which is mainly based upon the uncertainty of the 2323600300018 reference value, counting statistics, reference 2323600300019 efficiency and uncertainties on Q0 and FCd. 2323600300020 Data obtained in this work and previous 3 works 2323600300021 from REL-REFs: 2323600300022 E-gamma,keV Proposed k0-values 2323600300023 121.1 0.00218 +- 0.00005 2323600300024 136.0 0.00744 +- 0.00019 2323600300025 264.7 0.00752 +- 0.00019 2323600300026 279.5 0.00319 +- 0.00008 2323600300027 400.7 0.00145 +- 0.00004 2323600300028 The calculated thermal cross section based upon these 2323600300029 proposed k0-values is 54.45 b. 2323600300030 REL-REF (D,,X.Lin+,J,JRN,295,1921,2013) 2323600300031 Our results are systematically higher. 2323600300032 (A,,G.Kennedy+,J,JRN,257,(3),475,2003) 2323600300033 Our results match well. 2323600300034 (A,,R.Jacimovic+,J,NIM/A,622,415,2010) 2323600300035 Mainly the difference at 400 keV. 2323600300036 STATUS (TABLE) Table 7 of J,JRN,300,599,2014. 2323600300037 (DEP,23236002) In 23236002- initial exp.data. 2323600300038 ENDBIB 36 0 2323600300039 COMMON 2 3 2323600300040 EN-MIN-NM EN-MEAN-DN 2323600300041 EV EV 2323600300042 0.5 0.0253 2323600300043 ENDCOMMON 3 0 2323600300044 DATA 2 1 2323600300045 DATA DATA-ERR 2323600300046 NO-DIM NO-DIM 2323600300047 11.2 0.3 2323600300048 ENDDATA 3 0 2323600300049 ENDSUBENT 48 0 2323600399999 ENDENTRY 3 0 2323699999999