ENTRY L0053 19970129 0000L005300000001 SUBENT L0053001 19970129 0000L005300100001 BIB 14 81 L005300100002 INSTITUTE (1USALRL,3AULAML,1CANSAS,1CANTOR) L005300100003 REFERENCE (J,PR/C,26,777,8209) L005300100004 AUTHOR (J.W.JURY,B.L.BERMAN,J.G.WOODWORTH,N.T.THOMPSON, L005300100005 R.E.PYWELL,K.G.MCNEILL) L005300100006 TITLE Photoneutron cross sections for 15N. L005300100007 FACILITY (LINAC,1USALRL) L005300100008 INC-SOURCE (QMPH,ARAD) Positron annihilation in flight. L005300100009 The energy resolution (FWHM) of the annihilated- L005300100010 radiation component of the photon beam varied from L005300100011 150 keV for photon energies near 11 MeV to 450 keV forL005300100012 the highest energies used. L005300100013 SAMPLE The 62.0-g sample was in form of 15N gas (isotopic L005300100014 purity 98.9%) contained in a 1-m long by 2.54-cm L005300100015 diameter (volume=0.507 l) sample holder at a preasure L005300100016 of 11.5 mpa (113.5 atm). L005300100017 DETECTOR (BF3) Neutron 4pi detector, consisting of a 61-cm cube L005300100018 of paraffin containing 48 BF3 tubes arranged in four L005300100019 concentric rings of 12 tubes each. L005300100020 METHOD (EXTB,RINGR) Direct photoneutron detection. L005300100021 Ring-ratio neutron multiplicity measurement. L005300100022 ANALYSIS After the recorded neutron events were corrected for L005300100023 pileup in the detector, the neutron backgrounds L005300100024 (annihilation target removed) were substracted for L005300100025 both the positron and electron measurements. L005300100026 Because the energy spectrum of the annihilation-plus- L005300100027 Bremsstrahlung radiation differs from that of purely L005300100028 Bremsstrahlung photons, a measured correction was L005300100029 applied to the ion-chamber (beam monitor) response to L005300100030 normalize the electron data to the positron data. L005300100031 The normalized electron data then were substracted fromL005300100032 the positron data, leaving the neutron counts which L005300100033 result only from the annihilation radiation. L005300100034 The measured sample-blank data, normalized to equal L005300100035 photon flux, were substracted from the target data to L005300100036 give the net target results. L005300100037 After a small correction for the neutron multiplicity L005300100038 in each ring, the data were corrected for the energy- L005300100039 dependent efficiency of the neutron detector using theL005300100040 ring-ratio result for each energy. L005300100041 The data were converted to photoneutron cross sections L005300100042 by applying the measured ion-chamber response per L005300100043 photon, the known number of target nuclei in the beam,L005300100044 and a small correction for the photon attenuation in L005300100045 the sample. L005300100046 A multiplicity analysis of the number of neutrons L005300100047 recordered in each beam burst allows the (gamma,n) andL005300100048 (gamma,2n) yields to be extracted simultaneously and L005300100049 independently. L005300100050 ERR-ANALYS (DATA-ERR2) Possible systematic errors associated with L005300100051 the cross sections do not exceed 7% at energies below L005300100052 about 15 MeV, but might reach 20% at higher energies. L005300100053 CORRECTION Corrected for: L005300100054 - pileup of counts in the detector, L005300100055 - ion-chamber response to electron and positron, L005300100056 produced radiation, L005300100057 - neutron multiplicities in each ring, L005300100058 - photon attenuation in the sample. L005300100059 COMMENT A very broad giant dipole resonance extending from L005300100060 about 16 to 30 MeV was observed, with a maximum L005300100061 (gamma,n-tot) cross section of about 11 mb at 23.5 L005300100062 MeV. L005300100063 The magnitude of the measured average photoneutron L005300100064 energies shows that most of the strength below 15 MeV L005300100065 decays to the ground state of 14N, whereas most of theL005300100066 strength in the giant resonance decays to excited L005300100067 states. L005300100068 Comparison with particle-capture cross section data L005300100069 indicates that multiparticle-multihole interference L005300100070 effects probably account for some of the pronounced L005300100071 intermediate structure observed above 16 MeV in the L005300100072 (gamma,n) cross section. L005300100073 Comparison with a recent shell-model calculation favor L005300100074 the use of a Tabakin potential over a delta-function L005300100075 force with a sober exchange mixture, in marked L005300100076 contrast with recent corresponding results for 13C andL005300100077 17O. L005300100078 Comparisons are also made to features of recently L005300100079 measured photoreaction cross sections for 12,13C, L005300100080 14,15N, and 16,17,18O. L005300100081 HISTORY (891207C) L005300100082 (950406A) BIB Updated L005300100083 ENDBIB 81 0 L005300100084 COMMON 1 3 L005300100085 DATA-ERR2 L005300100086 PER-CENT L005300100087 20. L005300100088 ENDCOMMON 3 0 L005300100089 ENDSUBENT 88 0 L005300199999 SUBENT L0053002 19970129 0000L005300200001 BIB 3 4 L005300200002 REACTION ((7-N-15(G,N)7-N-14,,SIG)+(7-N-15(G,N+P)6-C-13,,SIG)) L005300200003 Threshold of the reaction (gamma,n+p) is 18.4 MeV. L005300200004 ERR-ANALYS (DATA-ERR1) Statistical errors only. L005300200005 STATUS Converted from Berman compilation. L005300200006 ENDBIB 4 0 L005300200007 NOCOMMON 0 0 L005300200008 DATA 3 102 L005300200009 EN DATA DATA-ERR1 L005300200010 MEV MB MB L005300200011 10.802 0.21 1.30 L005300200012 10.969 1.01 1.39 L005300200013 11.135 1.53 1.14 L005300200014 11.302 0.37 0.77 L005300200015 11.421 0.28 1.07 L005300200016 11.540 0.86 0.98 L005300200017 11.659 1.90 0.77 L005300200018 11.778 1.55 0.93 L005300200019 11.945 1.73 0.86 L005300200020 12.111 1.46 0.86 L005300200021 12.278 1.07 0.62 L005300200022 12.444 0.90 0.96 L005300200023 12.611 0.39 0.80 L005300200024 12.778 0.58 0.78 L005300200025 12.944 1.08 0.67 L005300200026 13.111 1.00 0.65 L005300200027 13.277 1.27 0.60 L005300200028 13.444 1.43 0.76 L005300200029 13.611 1.16 0.87 L005300200030 13.777 1.93 0.80 L005300200031 13.944 1.77 0.74 L005300200032 14.110 2.09 0.66 L005300200033 14.277 1.98 0.73 L005300200034 14.444 1.71 0.75 L005300200035 14.610 1.71 0.81 L005300200036 14.777 1.39 0.80 L005300200037 14.943 1.42 0.70 L005300200038 15.110 1.40 0.84 L005300200039 15.348 1.39 0.57 L005300200040 15.586 1.42 0.69 L005300200041 15.824 1.74 0.59 L005300200042 16.062 3.05 0.58 L005300200043 16.300 3.53 0.55 L005300200044 16.538 3.44 0.65 L005300200045 16.776 4.08 0.69 L005300200046 17.014 4.86 0.63 L005300200047 17.252 5.77 0.60 L005300200048 17.490 4.69 0.67 L005300200049 17.728 3.62 0.61 L005300200050 17.966 2.52 0.57 L005300200051 18.204 2.90 0.51 L005300200052 18.442 4.36 0.45 L005300200053 18.680 4.15 0.54 L005300200054 18.918 3.98 0.56 L005300200055 19.156 4.25 0.58 L005300200056 19.394 5.54 0.54 L005300200057 19.632 4.48 0.54 L005300200058 19.870 5.31 0.50 L005300200059 20.108 5.66 0.49 L005300200060 20.227 5.93 0.52 L005300200061 20.465 5.99 0.50 L005300200062 20.584 5.49 0.50 L005300200063 20.703 4.44 0.56 L005300200064 20.822 4.39 0.61 L005300200065 20.941 4.86 0.40 L005300200066 21.060 5.36 0.52 L005300200067 21.298 5.10 0.53 L005300200068 21.536 5.39 0.57 L005300200069 21.774 6.80 0.53 L005300200070 22.012 7.66 0.45 L005300200071 22.250 6.47 0.58 L005300200072 22.488 9.68 0.81 L005300200073 22.726 8.78 0.93 L005300200074 22.964 11.68 0.85 L005300200075 23.202 8.91 0.99 L005300200076 23.440 8.58 1.03 L005300200077 23.678 9.85 0.97 L005300200078 23.916 10.41 0.94 L005300200079 24.154 6.86 0.80 L005300200080 24.392 7.05 0.90 L005300200081 24.630 7.54 0.66 L005300200082 24.868 9.33 0.63 L005300200083 25.106 9.62 0.69 L005300200084 25.344 8.68 0.81 L005300200085 25.582 8.61 0.83 L005300200086 25.820 6.72 0.80 L005300200087 26.058 6.39 1.02 L005300200088 26.296 6.82 0.60 L005300200089 26.534 5.68 0.60 L005300200090 26.772 3.82 0.62 L005300200091 27.010 4.26 0.63 L005300200092 27.248 3.75 0.66 L005300200093 27.486 4.97 0.65 L005300200094 27.724 3.60 0.69 L005300200095 27.962 3.86 0.70 L005300200096 28.438 4.37 0.70 L005300200097 28.914 3.72 0.84 L005300200098 29.390 2.75 0.77 L005300200099 29.866 2.00 0.60 L005300200100 30.342 1.84 0.54 L005300200101 30.818 1.32 0.70 L005300200102 31.294 1.25 0.77 L005300200103 32.246 2.11 1.15 L005300200104 32.722 2.97 1.49 L005300200105 33.674 1.30 1.00 L005300200106 35.102 0.93 0.98 L005300200107 35.578 1.63 1.00 L005300200108 36.054 2.71 0.97 L005300200109 36.530 1.52 0.98 L005300200110 37.006 1.34 0.97 L005300200111 37.482 2.10 1.02 L005300200112 37.958 0.78 1.08 L005300200113 ENDDATA 104 0 L005300200114 ENDSUBENT 113 0 L005300299999 SUBENT L0053003 19970129 0000L005300300001 BIB 4 6 L005300300002 REACTION ((7-N-15(G,2N)7-N-13,,SIG)+ L005300300003 (7-N-15(G,2N+P)6-C-12,,SIG)) L005300300004 Threshold of the reaction (gamma,2n+p) is 23.3 MeV. L005300300005 ERR-ANALYS (DATA-ERR1) Statistical errors only. L005300300006 STATUS Converted from Berman compilation. L005300300007 HISTORY (950406A) REACTION corrected. L005300300008 ENDBIB 6 0 L005300300009 NOCOMMON 0 0 L005300300010 DATA 3 56 L005300300011 EN DATA DATA-ERR1 L005300300012 MEV MB MB L005300300013 19.632 -0.01 0.00 L005300300014 19.870 0.00 0.02 L005300300015 20.108 0.01 0.02 L005300300016 20.227 0.03 0.03 L005300300017 20.465 0.06 0.03 L005300300018 20.584 0.00 0.03 L005300300019 20.703 0.07 0.04 L005300300020 20.822 -0.01 0.01 L005300300021 20.941 0.01 0.02 L005300300022 21.060 0.00 0.02 L005300300023 21.298 0.05 0.03 L005300300024 21.536 0.03 0.03 L005300300025 21.774 0.04 0.03 L005300300026 22.012 0.00 0.03 L005300300027 22.250 0.08 0.04 L005300300028 22.488 0.09 0.04 L005300300029 22.726 0.12 0.05 L005300300030 22.964 0.05 0.04 L005300300031 23.202 0.17 0.06 L005300300032 23.440 0.06 0.05 L005300300033 23.678 0.05 0.04 L005300300034 23.916 0.04 0.05 L005300300035 24.154 0.21 0.07 L005300300036 24.392 0.00 0.15 L005300300037 24.630 0.32 0.08 L005300300038 24.868 0.20 0.08 L005300300039 25.106 0.48 0.10 L005300300040 25.344 0.88 0.13 L005300300041 25.582 0.89 0.14 L005300300042 25.820 0.90 0.14 L005300300043 26.058 0.79 0.23 L005300300044 26.296 0.70 0.11 L005300300045 26.534 0.70 0.11 L005300300046 26.772 0.91 0.15 L005300300047 27.010 0.70 0.15 L005300300048 27.248 0.89 0.16 L005300300049 27.486 0.60 0.15 L005300300050 27.724 0.94 0.16 L005300300051 27.962 0.89 0.16 L005300300052 28.438 0.72 0.14 L005300300053 28.914 0.58 0.18 L005300300054 29.390 0.66 0.18 L005300300055 29.866 0.84 0.16 L005300300056 30.342 0.79 0.17 L005300300057 30.818 1.01 0.19 L005300300058 31.294 0.77 0.19 L005300300059 32.246 0.68 0.20 L005300300060 32.722 0.63 0.20 L005300300061 33.674 0.31 0.14 L005300300062 35.102 0.17 0.12 L005300300063 35.578 0.25 0.12 L005300300064 36.054 0.18 0.11 L005300300065 36.530 0.29 0.12 L005300300066 37.006 0.16 0.12 L005300300067 37.482 0.10 0.12 L005300300068 37.958 0.12 0.13 L005300300069 ENDDATA 58 0 L005300300070 ENDSUBENT 69 0 L005300399999 SUBENT L0053004 19970129 0000L005300400001 BIB 3 4 L005300400002 REACTION (7-N-15(G,X)0-NN-1,,SIG) L005300400003 The sum: (G,N)+(G,N+P)+2(G,2N)+2(G,2N+P). L005300400004 ERR-ANALYS (DATA-ERR1) Statistical errors only. L005300400005 STATUS Converted from Berman compilation. L005300400006 ENDBIB 4 0 L005300400007 NOCOMMON 0 0 L005300400008 DATA 3 102 L005300400009 EN DATA DATA-ERR1 L005300400010 MEV MB MB L005300400011 10.802 0.21 1.30 L005300400012 10.969 1.01 1.39 L005300400013 11.135 1.53 1.14 L005300400014 11.302 0.37 0.77 L005300400015 11.421 0.28 1.07 L005300400016 11.540 0.86 0.98 L005300400017 11.659 1.90 0.77 L005300400018 11.778 1.55 0.93 L005300400019 11.945 1.73 0.86 L005300400020 12.111 1.46 0.86 L005300400021 12.278 1.07 0.62 L005300400022 12.444 0.90 0.96 L005300400023 12.611 0.39 0.80 L005300400024 12.778 0.58 0.78 L005300400025 12.944 1.08 0.67 L005300400026 13.111 1.00 0.65 L005300400027 13.277 1.27 0.60 L005300400028 13.444 1.43 0.76 L005300400029 13.611 1.16 0.87 L005300400030 13.777 1.93 0.80 L005300400031 13.944 1.77 0.74 L005300400032 14.110 2.09 0.66 L005300400033 14.277 1.98 .73 L005300400034 14.444 1.71 0.75 L005300400035 14.610 1.71 0.81 L005300400036 14.777 1.39 0.80 L005300400037 14.943 1.42 0.70 L005300400038 15.110 1.40 0.84 L005300400039 15.348 1.39 0.57 L005300400040 15.586 1.42 0.69 L005300400041 15.824 1.74 0.59 L005300400042 16.062 3.05 0.58 L005300400043 16.300 3.53 0.55 L005300400044 16.538 3.44 0.65 L005300400045 16.776 4.08 0.69 L005300400046 17.014 4.86 0.63 L005300400047 17.252 5.77 0.60 L005300400048 17.490 4.69 0.67 L005300400049 17.728 3.62 0.61 L005300400050 17.966 2.52 0.57 L005300400051 18.204 2.90 0.51 L005300400052 18.442 4.36 0.45 L005300400053 18.680 4.15 0.54 L005300400054 18.918 3.98 0.56 L005300400055 19.156 4.25 0.58 L005300400056 19.394 5.54 0.54 L005300400057 19.632 4.46 0.54 L005300400058 19.870 5.31 0.50 L005300400059 20.108 5.68 0.49 L005300400060 20.227 5.99 0.52 L005300400061 20.465 6.11 0.50 L005300400062 20.584 5.49 0.50 L005300400063 20.703 4.58 0.56 L005300400064 20.822 4.37 0.61 L005300400065 20.941 4.88 0.40 L005300400066 21.060 5.36 0.52 L005300400067 21.298 5.20 0.53 L005300400068 21.536 5.45 0.57 L005300400069 21.774 6.88 0.53 L005300400070 22.012 7.66 0.45 L005300400071 22.250 6.63 0.58 L005300400072 22.488 9.86 0.81 L005300400073 22.726 9.02 0.93 L005300400074 22.964 11.78 0.85 L005300400075 23.202 9.25 0.99 L005300400076 23.440 8.70 1.03 L005300400077 23.678 9.95 0.97 L005300400078 23.916 10.49 0.94 L005300400079 24.154 7.28 0.80 L005300400080 24.392 7.05 0.91 L005300400081 24.630 8.18 0.66 L005300400082 24.868 9.73 0.63 L005300400083 25.106 10.58 0.70 L005300400084 25.344 10.44 0.82 L005300400085 25.582 10.39 0.84 L005300400086 25.820 8.52 0.81 L005300400087 26.058 7.97 1.05 L005300400088 26.296 8.22 0.61 L005300400089 26.534 7.08 0.61 L005300400090 26.772 5.64 0.64 L005300400091 27.010 5.66 0.65 L005300400092 27.248 5.53 0.68 L005300400093 27.486 6.17 0.67 L005300400094 27.724 5.48 0.71 L005300400095 27.962 5.64 0.72 L005300400096 28.438 5.81 0.71 L005300400097 28.914 4.88 0.86 L005300400098 29.390 4.07 0.79 L005300400099 29.866 3.68 0.62 L005300400100 30.342 3.42 0.57 L005300400101 30.818 3.34 0.73 L005300400102 31.294 2.79 0.79 L005300400103 32.246 3.47 1.17 L005300400104 32.722 4.23 1.50 L005300400105 33.674 1.92 1.00 L005300400106 35.102 1.27 0.99 L005300400107 35.578 2.13 1.00 L005300400108 36.054 3.07 0.98 L005300400109 36.530 2.10 0.99 L005300400110 37.006 1.66 0.98 L005300400111 37.482 2.30 1.03 L005300400112 37.958 1.02 1.09 L005300400113 ENDDATA 104 0 L005300400114 ENDSUBENT 113 0 L005300499999 SUBENT L0053005 19970129 0000L005300500001 BIB 2 3 L005300500002 REACTION ((7-N-15(G,N)7-N-14,,INT)+(7-N-15(G,N+P)6-C-13,,INT)+ L005300500003 (7-N-15(G,2N)7-N-13,,INT)) L005300500004 STATUS (DEP,L0053004) Data taken from TABLE 2 in article L005300500005 ENDBIB 3 0 L005300500006 NOCOMMON 0 0 L005300500007 DATA 3 1 L005300500008 EN-MIN EN-MAX DATA L005300500009 MEV MEV MB*MEV L005300500010 10.8 38. 105.9 L005300500011 ENDDATA 3 0 L005300500012 ENDSUBENT 11 0 L005300599999 SUBENT L0053007 19970129 0000L005300700001 BIB 2 2 L005300700002 REACTION ((7-N-15(G,N)7-N-14,,INT)+(7-N-15(G,N+P)6-C-13,,INT)) L005300700003 STATUS (DEP,L0053002) Data taken from TABLE 2 in article L005300700004 ENDBIB 2 0 L005300700005 NOCOMMON 0 0 L005300700006 DATA 3 1 L005300700007 EN-MIN EN-MAX DATA L005300700008 MEV MEV MB*MEV L005300700009 10.8 38. 98.4 L005300700010 ENDDATA 3 0 L005300700011 ENDSUBENT 10 0 L005300799999 SUBENT L0053008 19970129 0000L005300800001 BIB 2 2 L005300800002 REACTION (7-N-15(G,2N)7-N-13,,INT) L005300800003 STATUS (DEP,L0053003) Data taken from TABLE 2 in article L005300800004 ENDBIB 2 0 L005300800005 NOCOMMON 0 0 L005300800006 DATA 3 1 L005300800007 EN-MIN EN-MAX DATA L005300800008 MEV MEV MB*MEV L005300800009 10.8 38. 7.6 L005300800010 ENDDATA 3 0 L005300800011 ENDSUBENT 10 0 L005300899999 ENDENTRY 7 0 L005399999999