ENTRY L0057 19970129 0000L005700000001 SUBENT L0057001 19970129 0000L005700100001 BIB 13 83 L005700100002 INSTITUTE (1USALRL,1USAGWU,1CANSAS,3AULAML,1CANTOR) L005700100003 REFERENCE (J,PR/C,36,1286,8705) L005700100004 (J,BAP,31,855(HH14),8604) L005700100005 AUTHOR (B.L.BERMAN,R.E.PYWELL,S.S.DIETRICH,M.N.THOMPSON, L005700100006 K.G.MCNEIL,J.W.JURY). L005700100007 TITLE Absolute photoneutron cross sections for Zr, I, Pr, L005700100008 Au, and Pb. L005700100009 FACILITY (LINAC,1USALRL) L005700100010 INC-SOURCE (QMPH,ARAD) Positron annihilation in flight. L005700100011 Energy resolution (FWHM) ranged from about 200 keV at L005700100012 the lowest energy (E(gamma) = 10 MeV) to around 400 L005700100013 keV at the highest energy (E(gamma) = 33 MeV). L005700100014 DETECTOR (BF3) Neutron 4pi detector, consisting of a 61-cm cube L005700100015 of paraffin containing 48 BF3 tubes arranged in four L005700100016 concentric rings of 12 tubes each. L005700100017 METHOD (EXTB,RINGR) Direct photoneutron detection. L005700100018 Ring-ratio neutron multiplicity measurement. L005700100019 A noteworthy feature of this experiment is the use of L005700100020 a remotely controlled pneumatic 8-position revolving L005700100021 sample changer, which allowed all of the samples, as L005700100022 well as a blank sample and a neutron calibration L005700100023 source, to be inserted into the center of 4pi neutron L005700100024 detector sequentially without changing the beam tuningL005700100025 or any other experimental conditions. This feature L005700100026 enabled relative cross section measurements to be madeL005700100027 with a precision of about 2%. This is much better L005700100028 than the overall absolute accuracy of about 5% typicalL005700100029 of recent measurements near the peak of the giant L005700100030 resonance of medium and heavy nuclei. L005700100031 ANALYSIS Photoneutrons from each sample and from a sample-blank L005700100032 were measured, both with and without the annihilation L005700100033 target present. After the recorded neutron events L005700100034 were corrected for pileup in the detector, the neutronL005700100035 backgrounds (annihilation target removed) were L005700100036 substracted for both the positron and electron L005700100037 measurements. L005700100038 Because the energy spectrum of the annihilation-plus- L005700100039 Bremsstrahlung radiation differs from that of purely L005700100040 Bremsstrahlung photons, a measured correction was L005700100041 applied to the ion-chamber (beam monitor) response to L005700100042 normalize the electron data to the positron data. L005700100043 The normalized electron data then were substracted fromL005700100044 the positron data, leaving the neutron counts which L005700100045 result only from the annihilation radiation. L005700100046 The measured sample-blank data, normalized to equal L005700100047 photon flux, were substracted from the target data to L005700100048 give the net target results. L005700100049 After a small correction for the neutron multiplicity L005700100050 in each ring, the data were corrected for the energy- L005700100051 dependent efficiency of the neutron detector using theL005700100052 ring-ratio result for each energy. L005700100053 The data were then converted to the photoneutron cross L005700100054 sections by applying the measured ion-chamber responseL005700100055 per photon, the known number of target nuclei in the L005700100056 beam, and a small correction for the photon L005700100057 attenuation in the sample. L005700100058 A multiplicity analysis of the number of neutrons L005700100059 recordered in each beam burst allows the (gamma,n) andL005700100060 (gamma,2n) yields to be extracted simultaneously and L005700100061 independently. L005700100062 ERR-ANALYS (DATA-ERR1) Statistical errors only. L005700100063 (DATA-ERR2) Uncertainty in absolute cross section does L005700100064 not exceed 10%, and results mainly from normalizationL005700100065 uncertainty and from the uncertainty in the absolute L005700100066 photon flux (about 5%). L005700100067 COMMENT These results resolve outstanding discrepancies among L005700100068 previous measurements. L005700100069 In view of the continuing controversy concerning L005700100070 discrepancies between the absolute values of certain L005700100071 photoneutron cross sections measured at Livermore and L005700100072 Saclay, the photoneutron cross sections near the peak L005700100073 of the giant dipole resonance for Zr, I, and Pb, were L005700100074 remeasured where previous results from the two L005700100075 laboratories were quite different, and for Pr and Au, L005700100076 where the previous results were essentially the same. L005700100077 The new results are in agreement with both sets of L005700100078 previous data for Pr and Au, with the Livermore L005700100079 results for Zr, and with Saclay results for Pb; L005700100080 for I, they fall midway between the two previous data L005700100081 sets. L005700100082 STATUS Converted from Berman compilation. L005700100083 HISTORY (891207C) L005700100084 (950406A) BIB updated L005700100085 ENDBIB 83 0 L005700100086 COMMON 1 3 L005700100087 DATA-ERR2 L005700100088 PER-CENT L005700100089 10. L005700100090 ENDCOMMON 3 0 L005700100091 ENDSUBENT 90 0 L005700199999 SUBENT L0057002 19970129 0000L005700200001 BIB 2 4 L005700200002 REACTION ((40-ZR-0(G,N),,SIG)+(40-ZR-0(G,N+P),,SIG)) L005700200003 Threshold of the reaction zr-91(gamma,n+p) is 15.6 MEV L005700200004 SAMPLE 113.4 gram solid sample in form of right circular L005700200005 cylinder of natural Zr, 51.5% 90Zr. L005700200006 ENDBIB 4 0 L005700200007 NOCOMMON 0 0 L005700200008 DATA 3 11 L005700200009 EN DATA DATA-ERR1 L005700200010 MEV MB MB L005700200011 14.938 107.65 2.74 L005700200012 15.416 132.60 2.49 L005700200013 15.895 156.88 3.25 L005700200014 16.373 158.92 3.67 L005700200015 16.851 149.15 3.97 L005700200016 17.329 120.45 4.05 L005700200017 17.807 105.14 4.34 L005700200018 18.285 89.62 4.70 L005700200019 18.763 73.66 4.88 L005700200020 19.242 66.58 5.12 L005700200021 19.720 50.56 7.71 L005700200022 ENDDATA 13 0 L005700200023 ENDSUBENT 22 0 L005700299999 SUBENT L0057003 19970129 0000L005700300001 BIB 2 3 L005700300002 REACTION (40-ZR-0(G,2N),,SIG) L005700300003 SAMPLE 113.4 gram solid sample in form of right circular L005700300004 cylinder of natural Zr, 51.5% 90Zr. L005700300005 ENDBIB 3 0 L005700300006 NOCOMMON 0 0 L005700300007 DATA 3 11 L005700300008 EN DATA DATA-ERR1 L005700300009 MEV MB MB L005700300010 14.938 1.00 0.40 L005700300011 15.416 3.92 0.50 L005700300012 15.895 8.47 0.80 L005700300013 16.373 15.61 0.99 L005700300014 16.851 20.57 1.12 L005700300015 17.329 26.92 1.18 L005700300016 17.807 26.35 1.29 L005700300017 18.285 24.59 1.36 L005700300018 18.763 23.25 1.40 L005700300019 19.242 21.43 1.46 L005700300020 19.720 25.03 2.16 L005700300021 ENDDATA 13 0 L005700300022 ENDSUBENT 21 0 L005700399999 SUBENT L0057004 19970129 0000L005700400001 BIB 2 4 L005700400002 REACTION (40-ZR-0(G,X)0-NN-1,UNW,SIG) L005700400003 The sum: (G,N)+(G,N+P)+(G,2N). L005700400004 SAMPLE 113.4 gram solid sample in form of right circular L005700400005 cylinder of natural Zr, 51.5% 90Zr. L005700400006 ENDBIB 4 0 L005700400007 NOCOMMON 0 0 L005700400008 DATA 3 11 L005700400009 EN DATA DATA-ERR1 L005700400010 MEV MB MB L005700400011 14.938 109.65 2.77 L005700400012 15.416 140.43 2.54 L005700400013 15.895 173.82 3.35 L005700400014 16.373 190.14 3.80 L005700400015 16.851 190.29 4.13 L005700400016 17.329 174.30 4.22 L005700400017 17.807 157.85 4.53 L005700400018 18.285 138.81 4.89 L005700400019 18.763 120.15 5.07 L005700400020 19.242 109.44 5.33 L005700400021 19.720 100.61 8.01 L005700400022 ENDDATA 13 0 L005700400023 ENDSUBENT 22 0 L005700499999 SUBENT L0057005 19970129 0000L005700500001 BIB 2 5 L005700500002 REACTION ((53-I-127(G,N)53-I-126,,SIG)+ L005700500003 (53-I-127(G,N+P)52-TE-125,,SIG)) L005700500004 Threshold of the reaction (gamma,n+p) is 15.3 MeV. L005700500005 SAMPLE 100.0 gram solid sample in form of right circular L005700500006 cylinder of natural I. L005700500007 ENDBIB 5 0 L005700500008 NOCOMMON 0 0 L005700500009 DATA 3 11 L005700500010 EN DATA DATA-ERR1 L005700500011 MEV MB MB L005700500012 12.069 82.71 1.82 L005700500013 12.548 102.70 2.24 L005700500014 13.026 127.75 2.45 L005700500015 13.504 163.64 2.75 L005700500016 13.982 203.26 3.53 L005700500017 14.460 235.02 4.11 L005700500018 14.938 252.26 2.91 L005700500019 15.416 245.35 3.81 L005700500020 15.895 228.06 5.72 L005700500021 16.373 216.08 4.37 L005700500022 16.851 169.21 5.89 L005700500023 ENDDATA 13 0 L005700500024 ENDSUBENT 23 0 L005700599999 SUBENT L0057006 19970129 0000L005700600001 BIB 2 3 L005700600002 REACTION (53-I-127(G,2N)53-I-125,,SIG) L005700600003 SAMPLE 100.0 gram solid sample in form of right circular L005700600004 cylinder of natural I. L005700600005 ENDBIB 3 0 L005700600006 NOCOMMON 0 0 L005700600007 DATA 3 4 L005700600008 EN DATA DATA-ERR1 L005700600009 MEV MB MB L005700600010 15.416 -0.31 0.77 L005700600011 15.895 1.50 1.35 L005700600012 16.373 2.09 1.08 L005700600013 16.851 21.35 1.69 L005700600014 ENDDATA 6 0 L005700600015 ENDSUBENT 14 0 L005700699999 SUBENT L0057007 19970129 0000L005700700001 BIB 2 4 L005700700002 REACTION (53-I-127(G,X)0-NN-1,,SIG) L005700700003 The sum: (G,N)+(G,N+P)+2(G,2N). L005700700004 SAMPLE 100.0 gram solid sample in form of right circular L005700700005 cylinder of natural I. L005700700006 ENDBIB 4 0 L005700700007 NOCOMMON 0 0 L005700700008 DATA 3 11 L005700700009 EN DATA DATA-ERR1 L005700700010 MEV MB MB L005700700011 12.069 82.71 1.82 L005700700012 12.548 102.70 2.24 L005700700013 13.026 127.75 2.45 L005700700014 13.504 163.64 2.75 L005700700015 13.982 203.26 3.53 L005700700016 14.460 235.02 4.11 L005700700017 14.938 252.26 2.91 L005700700018 15.416 244.73 3.89 L005700700019 15.895 231.06 5.88 L005700700020 16.373 220.26 4.50 L005700700021 16.851 211.92 6.13 L005700700022 ENDDATA 13 0 L005700700023 ENDSUBENT 22 0 L005700799999 SUBENT L0057008 19970129 0000L005700800001 BIB 2 5 L005700800002 REACTION ((59-PR-141(G,N)59-PR-140,,SIG)+ L005700800003 (59-PR-141(G,N+P)58-CE-139,,SIG)) L005700800004 Threshold of the reaction (gamma,n+p) is 14.4 MeV. L005700800005 SAMPLE 100.0 gram solid sample in form of right circular L005700800006 cylinder of natural Pr. L005700800007 ENDBIB 5 0 L005700800008 NOCOMMON 0 0 L005700800009 DATA 3 11 L005700800010 EN DATA DATA-ERR1 L005700800011 MEV MB MB L005700800012 12.069 89.88 1.98 L005700800013 12.548 116.61 2.56 L005700800014 13.026 148.70 2.71 L005700800015 13.504 193.74 3.11 L005700800016 13.982 246.18 3.73 L005700800017 14.460 289.24 4.33 L005700800018 14.938 337.49 3.23 L005700800019 15.416 338.43 3.27 L005700800020 15.895 310.34 3.39 L005700800021 16.373 259.71 2.49 L005700800022 16.851 212.53 2.44 L005700800023 ENDDATA 13 0 L005700800024 ENDSUBENT 23 0 L005700899999 SUBENT L0057009 19970129 0000L005700900001 BIB 2 5 L005700900002 REACTION ((79-AU-197(G,N)79-AU-196,,SIG)+ L005700900003 (79-AU-197(G,N+P)78-PT-195,,SIG)) L005700900004 Threshold of the reaction (gamma,n+p) is 13.7 MeV. L005700900005 SAMPLE 126.5 gram solid sample in form of right circular L005700900006 cylinder of natural Au. L005700900007 ENDBIB 5 0 L005700900008 NOCOMMON 0 0 L005700900009 DATA 3 11 L005700900010 EN DATA DATA-ERR1 L005700900011 MEV MB MB L005700900012 12.069 318.24 4.24 L005700900013 12.548 398.98 5.19 L005700900014 13.026 465.69 5.53 L005700900015 13.504 494.15 5.54 L005700900016 13.982 478.65 10.59 L005700900017 14.460 466.20 8.26 L005700900018 14.938 405.26 11.11 L005700900019 15.416 327.57 15.07 L005700900020 15.895 251.09 16.48 L005700900021 16.373 142.83 14.26 L005700900022 16.851 91.53 14.82 L005700900023 ENDDATA 13 0 L005700900024 ENDSUBENT 23 0 L005700999999 SUBENT L0057010 19970129 0000L005701000001 BIB 2 3 L005701000002 REACTION (79-AU-197(G,2N)79-AU-195,,SIG) L005701000003 SAMPLE 126.5 gram solid sample in form of right circular L005701000004 cylinder of natural Au. L005701000005 ENDBIB 3 0 L005701000006 NOCOMMON 0 0 L005701000007 DATA 3 7 L005701000008 EN DATA DATA-ERR1 L005701000009 MEV MB MB L005701000010 13.982 -0.66 2.44 L005701000011 14.460 -2.05 0.67 L005701000012 14.938 3.29 2.71 L005701000013 15.416 32.15 3.77 L005701000014 15.895 59.89 4.14 L005701000015 16.373 95.47 3.63 L005701000016 16.851 104.78 3.77 L005701000017 ENDDATA 9 0 L005701000018 ENDSUBENT 17 0 L005701099999 SUBENT L0057011 19970129 0000L005701100001 BIB 2 4 L005701100002 REACTION (79-AU-197(G,X)0-NN-1,,SIG) L005701100003 The sum: (G,N)+(G,N+P)+2(G,2N). L005701100004 SAMPLE 126.5 gram solid sample in form of right circular L005701100005 cylinder of natural Au. L005701100006 ENDBIB 4 0 L005701100007 NOCOMMON 0 0 L005701100008 DATA 3 11 L005701100009 EN DATA DATA-ERR1 L005701100010 MEV MB MB L005701100011 12.069 318.24 4.24 L005701100012 12.548 398.98 5.19 L005701100013 13.026 465.69 5.53 L005701100014 13.504 494.15 5.54 L005701100015 13.982 477.34 10.87 L005701100016 14.460 462.09 8.29 L005701100017 14.938 411.84 11.43 L005701100018 15.416 391.86 15.53 L005701100019 15.895 370.87 16.99 L005701100020 16.373 333.77 14.72 L005701100021 16.851 301.09 15.29 L005701100022 ENDDATA 13 0 L005701100023 ENDSUBENT 22 0 L005701199999 SUBENT L0057012 19970129 0000L005701200001 BIB 3 5 L005701200002 REACTION ((82-PB-0(G,N),,SIG)+(82-PB-0(G,N+P),,SIG)) L005701200003 Threshold of the reaction 207pb(gamma,n+p) is 14.0 MEV L005701200004 SAMPLE 99.7 gram solid sample in form of right circular L005701200005 cylinder of natural Pb, 52.4% 208Pb. L005701200006 STATUS Converted from Berman compilation. L005701200007 ENDBIB 5 0 L005701200008 NOCOMMON 0 0 L005701200009 DATA 3 11 L005701200010 EN DATA DATA-ERR1 L005701200011 MEV MB MB L005701200012 12.069 424.16 5.89 L005701200013 12.548 483.12 6.94 L005701200014 13.026 554.28 6.98 L005701200015 13.504 613.28 7.94 L005701200016 13.982 596.23 11.89 L005701200017 14.460 540.38 14.46 L005701200018 14.938 395.36 15.97 L005701200019 15.416 282.52 17.01 L005701200020 15.895 178.63 17.61 L005701200021 16.373 107.25 13.31 L005701200022 16.851 60.04 14.71 L005701200023 ENDDATA 13 0 L005701200024 ENDSUBENT 23 0 L005701299999 SUBENT L0057013 19970129 0000L005701300001 BIB 2 3 L005701300002 REACTION (82-PB-0(G,2N),,SIG) L005701300003 SAMPLE 99.7 gram solid sample in form of right circular L005701300004 cylinder of natural Pb, 52.4% 208Pb. L005701300005 ENDBIB 3 0 L005701300006 NOCOMMON 0 0 L005701300007 DATA 3 8 L005701300008 EN DATA DATA-ERR1 L005701300009 MEV MB MB L005701300010 13.504 -0.13 0.90 L005701300011 13.982 -0.40 0.52 L005701300012 14.460 7.55 3.12 L005701300013 14.938 29.20 3.56 L005701300014 15.416 57.43 4.04 L005701300015 15.895 76.92 4.27 L005701300016 16.373 87.55 3.27 L005701300017 16.851 93.56 3.69 L005701300018 ENDDATA 10 0 L005701300019 ENDSUBENT 18 0 L005701399999 SUBENT L0057014 19970129 0000L005701400001 BIB 2 4 L005701400002 REACTION (82-PB-0(G,X)0-NN-1,,SIG) L005701400003 The sum: (G,N)+(G,N+P)+2(G,2N). L005701400004 SAMPLE 99.7 gram solid sample in form of right circular L005701400005 cylinder of natural Pb, 52.4% 208Pb. L005701400006 ENDBIB 4 0 L005701400007 NOCOMMON 0 0 L005701400008 DATA 3 11 L005701400009 EN DATA DATA-ERR1 L005701400010 MEV MB MB L005701400011 12.069 424.16 5.89 L005701400012 12.548 483.12 6.94 L005701400013 13.026 554.28 6.98 L005701400014 13.504 613.02 7.99 L005701400015 13.982 595.43 12.16 L005701400016 14.460 555.48 14.79 L005701400017 14.938 453.76 16.37 L005701400018 15.416 397.39 17.49 L005701400019 15.895 332.47 18.12 L005701400020 16.373 282.34 13.71 L005701400021 16.851 247.16 15.17 L005701400022 ENDDATA 13 0 L005701400023 ENDSUBENT 22 0 L005701499999 SUBENT L0057015 19970129 0000L005701500001 BIB 2 6 L005701500002 REACTION ((59-PR-141(G,N)59-PR-140,,SIG)+ L005701500003 (59-PR-141(G,N+P)58-CE-139,,SIG)) L005701500004 Threshold of the reaction (gamma,n+p) is 14.4 MeV. L005701500005 Data labeled 1980, 1986. L005701500006 SAMPLE 100.0 gram solid sample in form of right circular L005701500007 cylinder of natural Pr. L005701500008 ENDBIB 6 0 L005701500009 NOCOMMON 0 0 L005701500010 DATA 3 11 L005701500011 EN DATA DATA-ERR1 L005701500012 MEV MB MB L005701500013 13.71 223.5 2.75 L005701500014 13.95 253.5 3.00 L005701500015 14.20 273.5 3.00 L005701500016 14.44 304.0 3.25 L005701500017 14.69 322.5 3.25 L005701500018 14.93 342.5 3.50 L005701500019 15.12 350.5 3.25 L005701500020 15.42 333.5 3.50 L005701500021 15.67 332.5 3.50 L005701500022 15.91 305.5 3.00 L005701500023 16.16 292.3 3.50 L005701500024 ENDDATA 13 0 L005701500025 ENDSUBENT 24 0 L005701599999 ENDENTRY 15 0 L005799999999