ENTRY 30947 20090914 31413094700000001 SUBENT 30947001 20090914 31413094700100001 BIB 13 61 3094700100002 TITLE Fission of 232Th by reactor neutrons: mass-yield curve 3094700100003 AUTHOR (R.H.Iyer,C.K.Mathews,N.Ravindran,K.Rengan, D.V.Singh, 3094700100004 M.V.Ramaniah,H.D.Sharma) 3094700100005 INSTITUTE (3INDTRM) 3094700100006 REFERENCE (J,JIN,25,465,1963) 3094700100007 FACILITY (REAC,3INDTRM) Apsara swimming pool reactor 3094700100008 INC-SPECT Pile neutrons from core of Apsara reactor; samples 3094700100009 irradiated in the same position for 15 min to 40 hrs. 3094700100010 Fluctuations of reactor power level during irradiations3094700100011 were small and did not affect results. 3094700100012 Compiler's comment (ML): for the coding of reaction and3094700100013 neutron energy, the spectrum of neutrons fissioning 3094700100014 Th-232 (fission threshold about 1.1 MeV) was assumed 3094700100015 to be (close to) a fission spectrum. 3094700100016 SAMPLE For irradiation: 3094700100017 Thorium: pure oxide, hydrocarbonate, or metal foils:3094700100018 <0.5 ppm uranium, <0.8 ppm cerium, 3094700100019 <0.2 ppm samarium, <0.08 ppm iron. 3094700100020 Th oxide: 10 g samples 3094700100021 Uranium: metal foils, 0.5 g samples 3094700100022 Samples in separate pure aluminium foils, enclosed 3094700100023 in the same pure aluminium containers. 3094700100024 For counting: 3094700100025 Separated fission products centred on aluminium 3094700100026 plates and covered with 3 mg/cm2 cellophane paper. 3094700100027 METHOD (RVAL).Relative U-235 thermal fission, standard: Mo-99;3094700100028 Simultaneous irradiation of Th and U samples; 3094700100029 counting of samples under identical conditions. 3094700100030 (RCHEM). Samples were dissolved, fission products 3094700100031 chemically separated and mounted for counting. 3094700100032 (BSPEC,GSPEC).Counted long enough to keep statistical 3094700100033 error below 1%; if possible, until complete decay. 3094700100034 DETECTOR (PROPC).Betas: Sugarman-type methane flow counter, end 3094700100035 window covered with 1.1 mg/cm2 aluminised mylar 3094700100036 (NAICR).Gammas: 1.5x1 inch, single channel or 100 3094700100037 channel pulse hight analyser. 3094700100038 ANALYSIS (DECAY) 3094700100039 CORRECTION 1) For aliquot and chemical yield 3094700100040 2) For decay after irradiation 3094700100041 3) Counting: for self-absorption and scattering; 3094700100042 Corrections for decay during irradiation cancelled out 3094700100043 in the R-value because of simultaneous irradiation 3094700100044 of samples. The authors assumed that the genetic 3094700100045 relationships are the same in Th-232 fast and U-235 3094700100046 thermal neutron fission under the conditions of the 3094700100047 experiment and for the fission products considered. 3094700100048 They discussed the complicated decay schemes and 3094700100049 existing isomers for the isotopes of Ag, Cd, In and 3094700100050 Sn, which they could not correct for, and concluded 3094700100051 that the corresponding errors in R-values should 3094700100052 have been small. 3094700100053 Corrections for U-235 fast fission were negligible. 3094700100054 Contributions from secondary noutron fission in large 3094700100055 thorium targets were estimated to be less than 1% 3094700100056 and could be neglected. 3094700100057 No corrections were applied for neutron capture. 3094700100058 STATUS (RIDER).Ref. 63IYE1.data from Table 1 of 1st reference 3094700100059 HISTORY (19881017T) Converted to Exfor90236 by NNDC 3094700100060 (19911127A) ML: converted to regular exfor; revised 3094700100061 completely, added subentry 3 3094700100062 (20090912A) SD:Updated to new date formats,lower case. 3094700100063 ENDBIB 61 0 3094700100064 NOCOMMON 0 0 3094700100065 ENDSUBENT 64 0 3094700199999 SUBENT 30947002 20090914 31413094700200001 BIB 7 22 3094700200002 REACTION (((90-TH-232(N,F)ELEM/MASS,CUM,FY,,FIS)/ 3094700200003 (90-TH-232(N,F)42-MO-99,CUM,FY,,FIS))// 3094700200004 ((92-U-235(N,F)ELEM/MASS,CUM,FY,,MXW)/ 3094700200005 (92-U-235(N,F)42-MO-99,CUM,FY,,MXW))) 3094700200006 RESULT (RVAL) 3094700200007 DECAY-DATA Taken from: E.P.Steinberg and L.Glendenin, 1st Int. 3094700200008 Conf. Peaceful Uses of Atomic Energy, Geneva, 1955; 3094700200009 Proceed., vol.7, paper p/614. 3094700200010 Comment: values are not given but corrections are small3094700200011 (see 'CORRECTION'). 3094700200012 REL-REF (R,,E.P.Steinberg+,C,55GENEVA,7,614,1955) 3094700200013 ERR-ANALYS (ERR-S) Errors are statistical, given as 1 standard 3094700200014 deviation. 3094700200015 Compilers comment (ML): No detailed information; 3094700200016 obviously, errors were calculated as standard 3094700200017 deviations from the mean of the results of different3094700200018 determinations (no error given for value obtained 3094700200019 from one determination). 3094700200020 COMMENT by compiler (ML): In-117 is given as the ground state 3094700200021 by the authors in the table, although the metastable3094700200022 state has a longer half life. 3094700200023 MISC-COL (MISC) Number of determinations 3094700200024 ENDBIB 22 0 3094700200025 COMMON 2 3 3094700200026 EN-DUM-NM EN-DUM-DN 3094700200027 EV EV 3094700200028 1.0 E+06 0.0253 3094700200029 ENDCOMMON 3 0 3094700200030 DATA 6 30 3094700200031 ELEMENT MASS ISOMER DATA ERR-S MISC 3094700200032 NO-DIM NO-DIM NO-DIM NO-DIM NO-DIM NO-DIM 3094700200033 33. 77. 2.83 0.14 3. 3094700200034 35. 83. 8.21 0.59 3. 3094700200035 38. 90. 2.8 0.1 2. 3094700200036 38. 91. 2.55 0.20 4. 3094700200037 40. 95. 1.81 0.11 2. 3094700200038 40. 97. 1.56 0.02 2. 3094700200039 44. 103. 0.110 0.005 3. 3094700200040 44. 106. 0.230 0.012 3. 3094700200041 45. 105. 0. 0.072 0.003 2. 3094700200042 46. 109. 0. 3.71 0.28 3. 3094700200043 46. 112. 14.1 1.3 2. 3094700200044 47. 111. 0. 7.7 0.7 3. 3094700200045 47. 113. 0. 11.65 0.85 3. 3094700200046 48. 115. 0. 11.6 0.6 4. 3094700200047 48. 115. 1. 16.3 4.3 4. 3094700200048 49. 117. 0. 10.44 1.22 2. 3094700200049 50. 121. 0. 8.77 0.40 2. 3094700200050 50. 123. 0. 4.19 0.18 2. 3094700200051 50. 125. 0. 2.70 0.27 3. 3094700200052 51. 127. 1.52 0.07 4. 3094700200053 53. 131. 1.22 0.05 3. 3094700200054 55. 137. 1.58 0.02 2. 3094700200055 56. 139. 2.21 0.11 3. 3094700200056 56. 140. 2.92 0.08 5. 3094700200057 58. 141. 2.86 0.13 2. 3094700200058 58. 144. 2.88 0.01 2. 3094700200059 59. 143. 2.66 0.09 4. 3094700200060 60. 147. 3.08 0.16 4. 3094700200061 61. 149. 1.82 1. 3094700200062 63. 156. 0.410 0.051 2. 3094700200063 ENDDATA 32 0 3094700200064 ENDSUBENT 63 0 3094700299999 SUBENT 30947003 20090914 31413094700300001 BIB 7 42 3094700300002 REACTION (90-TH-232(N,F)ELEM/MASS,CUM,FY,,FIS) 3094700300003 ANALYSIS The fission product yields from Th-232 (=Y(fp,2)) are 3094700300004 calculated from the measured R-values (=R) and the 3094700300005 U-235 fission yields (=Y(fp,5)) according to: 3094700300006 Y(fp,2) = R * Y(99,2) * Y(fp,5)/Y(99,5) 3094700300007 where Y(99,2) and Y(99,5) are the corresponding 3094700300008 Mo-99 yields. 3094700300009 MONITOR ((MONIT1)90-TH-232(N,F)42-MO-99,CUM,FY,,FIS) = Y(99,2) 3094700300010 obtained by normalising the relative Th-232 yields 3094700300011 (including estimated yields) to a total of 200%. 3094700300012 ((MONIT2)92-U-235(N,F)ELEM/MASS,CUM,FY,,FIS) = Y(fp,5) 3094700300013 ((MONIT3)92-U-235(N,F)42-MO-99,CUM,FY,,FIS) = Y(99,5) 3094700300014 MONIT-REF (,S.KATCOFF,J,NUC,18,(11),201,1960) All U-235 yields 3094700300015 ERR-ANALYS (ERR-S) The errors in the data Table correspond to the 3094700300016 statistical errors of the R-values, to which the 3094700300017 following errors have to be added: 3094700300018 Errors of U-235 thermal yields; 3094700300019 Additional uncertainties from complicated decay schemes3094700300020 in the valley region (see: correction); 3094700300021 The largest error contribution comes from the Th-232 3094700300022 yield curve normalisation. 3094700300023 The total error is estimated to be about 10-20%. 3094700300024 COMMENT by compiler (ML): 3094700300025 1) The final Th-232 yields as given by the authors are 3094700300026 included to give an idea of the absolute yield 3094700300027 values. However, the U-235 reference yields are 3094700300028 superseded, and absolute yields will change 3094700300029 considerably, especially in the valley region, if 3094700300030 up-to-date U-235 yields are used. 3094700300031 2) 2 Misprints in Table 1 of the publication for Ba-1393094700300032 (corrected in data Table) 3094700300033 - The U-235 reference yield is given as 5.55; 3094700300034 - The error of the Th-232 yield is given as 0.033. 3094700300035 3) Differences in U-235 reference yields compared to 3094700300036 those given by Katcoff (Monit-ref): 3094700300037 - Rh-105: Value in Monit-ref is for Ru-105 3094700300038 - Ag-113: No value given in Monit-ref for A=113 3094700300039 - In-117: Value in Monit-ref is for Cd-117m (3 hr) 3094700300040 - Sn-125: Value in Monit-ref is for Sb-125 3094700300041 - Pr-143: Not given in Monit-ref;does not agree 3094700300042 with values for Ce-143 or Nd-143. 3094700300043 STATUS (DEP,30947002) Derived from measured R-values 3094700300044 ENDBIB 42 0 3094700300045 COMMON 6 3 3094700300046 EN-DUMMY EN-NRM1 MONIT1 EN-NRM2 EN-NRM3 MONIT3 3094700300047 MEV MEV PC/FIS EV EV PC/FIS 3094700300048 1. 1. 2.78 0.0253 0.0253 6.06 3094700300049 ENDCOMMON 3 0 3094700300050 DATA 6 30 3094700300051 ELEMENT MASS ISOMER MONIT2 DATA ERR-S 3094700300052 NO-DIM NO-DIM NO-DIM PC/FIS PC/FIS PC/FIS 3094700300053 33. 77. 0.008 0.0110 0.0006 3094700300054 35. 83. 0.510 1.92 0.14 3094700300055 38. 90. 5.77 7.41 0.27 3094700300056 38. 91. 5.81 6.80 0.55 3094700300057 40. 95. 6.20 5.15 0.31 3094700300058 40. 97. 5.90 4.22 0.06 3094700300059 44. 103. 3.00 0.150 0.007 3094700300060 44. 106. 0.38 0.0400 0.0021 3094700300061 45. 105. 0. 0.9 0.0300 0.0014 3094700300062 46. 109. 0. 0.030 0.051 0.004 3094700300063 46. 112. 0.010 0.065 0.006 3094700300064 47. 111. 0. 0.019 0.067 0.006 3094700300065 47. 113. 0. 0.011 0.059 0.004 3094700300066 48. 115. 0. 0.0097 0.052 0.002 3094700300067 48. 115. 1. 0.0007 0.0052 0.0014 3094700300068 49. 117. 0. 0.011 0.053 0.006 3094700300069 50. 121. 0. 0.015 0.060 0.003 3094700300070 50. 123. 0. 0.015 0.0290 0.0012 3094700300071 50. 125. 0. 0.021 0.026 0.002 3094700300072 51. 127. 0.13 0.091 0.004 3094700300073 53. 131. 3.10 1.73 0.07 3094700300074 55. 137. 6.15 4.46 0.06 3094700300075 56. 139. 6.55 6.64 0.33 3094700300076 56. 140. 6.35 8.50 0.23 3094700300077 58. 141. 6.0 7.87 0.36 3094700300078 58. 144. 6.0 7.93 0.03 3094700300079 59. 143. 6.00 7.32 0.25 3094700300080 60. 147. 2.7 3.82 0.20 3094700300081 61. 149. 1.13 0.945 3094700300082 63. 156. 0.014 0.0027 0.0003 3094700300083 ENDDATA 32 0 3094700300084 ENDSUBENT 83 0 3094700399999 ENDENTRY 3 0 3094799999999