ENTRY 21763 19820730 00002176300000001 SUBENT 21763001 19820730 00002176300100001 BIB 14 79 2176300100002 INSTITUTE (2ZZZGEL) 2176300100003 REFERENCE (W,H.-H..KNITTER+,810313) 2176300100004 (P,INDC(EUR)-14,5,8103) 2176300100005 AUTHOR (H.-H.KNITTER,C.BUDTZ-JOERGENSEN,D.L.SMITH) 2176300100006 TITLE -NEUTRON INDUCED FISSION CROSS SECTION OF PU-238 2176300100007 IN THE ENERGY RANGE FROM 150 KEV TO 10 MEV 2176300100008 FACILITY (VDG ) 7 MV VAN DER GRAAFF 2176300100009 INC-SOURCE (P-LI7) NEUTRON ENERGIES 146 KEV TO 993 KEV 2176300100010 (P-T ) NEUTRON ENERGIES 1 MEV TO 4 MEV 2176300100011 (D-D ) NEUTRON ENERGIES 3.95 MEV TO 10 MEV 2176300100012 DETAILS OF GAS TARGET GIVEN IN 2176300100013 (J,AKE,33,205,7900) 2176300100014 .VAN DER GRAAFF OPERATED IN PULSED MODE, 2176300100015 AVERAGE CURRENT = 4 MICRO-A, PULSE WIDTH = 2176300100016 1.5 NANOSEC, REPETITION FREQUENCY = 2.5 MHZ 2176300100017 .NEUTRON ENERGY SPREAD = 60 KEV FOR P-LI7, 2176300100018 = 70 - 150 KEV FOR P-T, = 180 - 660 KEV FOR D-D 2176300100019 .UNCERTAINTY IN AVERAGE NEUTRON ENERGY = 2176300100020 +-5 KEV FOR P-LI7, = +-15 KEV FOR P-T, 2176300100021 = +- 50 KEV FOR D-D 2176300100022 SAMPLE .U-F4 EVAPORATED ONTO, OR PU OXIDE HARDFIRED ONTO 2176300100023 0.5 MM THICK STAINLESS STEEL BACKING. 2176300100024 .DIAMETER OF FISSILE LAYER = 28 MM 2176300100025 .SAMPLE WEIGHT IN MICRO-G 2176300100026 1) PU 53.24 +- 0.5 2) U 591.7 +- 3.0 2176300100027 .ISOTOPIC CONTENT IN ATOM PERCENT 2176300100028 1) PU-238 89.63 PU-239 9.71 2176300100029 PU-240 0.634 PU-241 0.0204 2176300100030 PU-242 0.0069 2176300100031 2) U-235 99.1896 U-234 0.1776 2176300100032 U-236 0.0310 U-238 0.6018 2176300100033 METHOD (TOF ) BACK TO BACK SAMPLES OF PU AND U IN NEUTRON 2176300100034 BEAM. FISSION FRAGMENT DETECTORS DISCRIMINATE AGAINST 2176300100035 ALPHAS FROM PU DECAY. CROSS SECTION RATIO CALCULATED 2176300100036 FROM RATIO OF MEASURED FISSION EVENTS, CORRECTED AS 2176300100037 DETAILED BELOW. 2176300100038 .TIME OF FLIGHT NEUTRON DETECTOR INSTALLED 11.30 M 2176300100039 FROM NEUTRON SOURCE AT ZERO DEGREES. 2176300100040 1) TO MONITOR NEUTRON PRODUCTION DURING MEASUREMENTS 2176300100041 2) TO MEASURE ENERGY SPECTRUM OF 2176300100042 NEUTRONS FROM D-D TARGET. 2176300100043 DETECTOR (FISCH) CONVENTIONAL DESIGN USED FOR U-235 FISSION 2176300100044 FRAGMENTS, DESIGN USED FOR PU-238 FRAGMENTS IS 2176300100045 DETAILED IN (J,AKE,33,205,7900) 2176300100046 COMMENT .NO DATA PREVIOUSLY EXISTED IN 5 TO 10 MEV REGION. 2176300100047 STATUS .DATA TAKEN FROM FIRST REFERENCE. 2176300100048 HISTORY (820114C) A.P.T. 2176300100049 (820217E) 2176300100050 CORRECTION .BACKGROUND EVENTS ( SPONTANEOUS FISSION, FISSION 2176300100051 INDUCED BY BACKGROUND NEUTRONS, ALPHAS FROM PU-DECAY) 2176300100052 SUBTRACTED. BACKGROUND LESS THAN 2 PERCENT FOR U-235. 2176300100053 FOR PU-238 LESS THAN 5 PERCENT FOR P-LI7 AND P-T 2176300100054 TARGETS, BUT EXCEEDS 100 PERCENT BELOW A NEUTRON 2176300100055 ENERGY OF 200 KEV. 2176300100056 .FISSION EVENTS DUE TO PU-239 AND PU-241. 2176300100057 .DIFFERENCES IN GEOMETRY OF PU AND U SAMPLES RELATIVE 2176300100058 TO THE NEUTRON SOURCE, INCLUDING THE EFFECT OF THE 2176300100059 BACKING MATERIAL ON THE NEUTRON FLUX. 2176300100060 .DETECTOR EFFICIENCIES, INCLUDING THE ABSORPTION OF 2176300100061 FISSION FRAGMENTS IN THE FISSILE SAMPLES AND 2176300100062 NON-DETECTION DUE TO REACTION KINEMATICS. 2176300100063 .FOR P-LI7 TARGET THERE IS A WEAK SECOND GROUP OF 2176300100064 NEUTRONS DUE TO AN EXCITED FINAL STATE OF 4-BE-7. 2176300100065 .FOR DEUTERIUM GAS TARGET CORRECTIONS FOR NEUTRONS 2176300100066 PRODUCED BY STRUCTURAL MATERIAL OR ( ABOVE 5 MEV 2176300100067 NEUTRON ENERGY ) BY D(D,NP)D BREAKUP REACTION. 2176300100068 ERR-ANALYS (ERR-1) TYPICAL U-235 FISSION FRAGMENT 2176300100069 DETECTION EFFICIENCY 2176300100070 (ERR-2) TYPICAL PU-238 FISSION FRAGMENT 2176300100071 DETECTION EFFICIENCY 2176300100072 (ERR-3) ERROR IN NUMBER OF U-235 ATOMS IN SAMPLE 2176300100073 (ERR-4) ERROR IN NUMBER OF PI-238 ATOMS IN SAMPLE 2176300100074 (ERR-5) ERROR IN GEOMETRIC CORRECTION 2176300100075 (ERR-S) TOTAL UNCORRELATED ERROR COMPUTED FROM 2176300100076 QUADRATIC SUM OF ERRORS IN FISSION EVENT 2176300100077 COUNT FOR U AND PU SAMPLES 2176300100078 (RATIO-ERR) TOTAL ERROR FOR EACH DATA POINT 2176300100079 .IN TABLE 2 OF FIRST REFERENCE THERE IS A QUOTED ERROR 2176300100080 IN THE NUMBER OF FISSION EVENTS DUE TO PU-239 2176300100081 ENDBIB 79 0 2176300100082 NOCOMMON 0 0 2176300100083 ENDSUBENT 82 0 2176300199999 SUBENT 21763002 19820730 00002176300200001 BIB 2 2 2176300200002 REACTION ((94-PU-238(N,F),,SIG)/(92-U-235(N,F),,SIG)) 2176300200003 STATUS .DATA TAKEN FROM FIRST REFERENCE 2176300200004 ENDBIB 2 0 2176300200005 COMMON 6 3 2176300200006 ERR-1 ERR-2 ERR-3 ERR-4 ERR-5 ERR-S 2176300200007 PER-CENT PER-CENT PER-CENT PER-CENT PER-CENT PER-CENT 2176300200008 7.0000E-01 1.6000E+00 5.0000E-01 1.0000E+00 6.0000E-01 3.5000E+002176300200009 ENDCOMMON 3 0 2176300200010 DATA 3 89 2176300200011 EN RATIO RATIO-ERR 2176300200012 MEV NO-DIM NO-DIM 2176300200013 1.4600E-01 4.7470E-01 1.7000E-02 2176300200014 1.4700E-01 4.5320E-01 1.7000E-02 2176300200015 1.9600E-01 5.6190E-01 2.1000E-02 2176300200016 1.9600E-01 4.0790E-01 1.6000E-02 2176300200017 1.9600E-01 5.3090E-01 2.0000E-02 2176300200018 1.9700E-01 5.6200E-01 2.1000E-02 2176300200019 2.4600E-01 6.3600E-01 2.3000E-02 2176300200020 2.4700E-01 6.8050E-01 2.6000E-02 2176300200021 2.9500E-01 6.7490E-01 2.4000E-02 2176300200022 2.9700E-01 6.0910E-01 2.4000E-02 2176300200023 3.4500E-01 7.8190E-01 2.8000E-02 2176300200024 3.4500E-01 7.1610E-01 2.6000E-02 2176300200025 3.4700E-01 8.3290E-01 3.1000E-02 2176300200026 3.9500E-01 8.5510E-01 3.1000E-02 2176300200027 4.4500E-01 1.0290E+00 3.6000E-02 2176300200028 4.4600E-01 9.5510E-01 3.4000E-02 2176300200029 4.9500E-01 1.1650E+00 4.1000E-02 2176300200030 5.4400E-01 1.3600E+00 4.7000E-02 2176300200031 5.9400E-01 1.4560E+00 5.1000E-02 2176300200032 5.9600E-01 1.4840E+00 5.2000E-02 2176300200033 6.4400E-01 1.5160E+00 5.3000E-02 2176300200034 6.9400E-01 1.7030E+00 5.9000E-02 2176300200035 7.4300E-01 1.6490E+00 5.7000E-02 2176300200036 7.9300E-01 1.8530E+00 6.4000E-02 2176300200037 8.4300E-01 1.6970E+00 5.9000E-02 2176300200038 8.9300E-01 1.6080E+00 5.6000E-02 2176300200039 9.4300E-01 1.6150E+00 5.6000E-02 2176300200040 9.9200E-01 1.6480E+00 5.7000E-02 2176300200041 1.0000E+00 1.7140E+00 6.0000E-02 2176300200042 1.1000E+00 1.6410E+00 5.7000E-02 2176300200043 1.2000E+00 1.7030E+00 5.9000E-02 2176300200044 1.3000E+00 1.7150E+00 6.0000E-02 2176300200045 1.4000E+00 1.6700E+00 5.8000E-02 2176300200046 1.5000E+00 1.7360E+00 6.1000E-02 2176300200047 1.6000E+00 1.7190E+00 6.0000E-02 2176300200048 1.7000E+00 1.7420E+00 6.1000E-02 2176300200049 1.8000E+00 1.6730E+00 5.8000E-02 2176300200050 1.9000E+00 1.7480E+00 6.1000E-02 2176300200051 2.0000E+00 1.7260E+00 6.0000E-02 2176300200052 2.1000E+00 1.8070E+00 6.3000E-02 2176300200053 2.2000E+00 1.8180E+00 6.3000E-02 2176300200054 2.3000E+00 1.7580E+00 6.1000E-02 2176300200055 2.4000E+00 1.8510E+00 6.5000E-02 2176300200056 2.5000E+00 1.8520E+00 6.5000E-02 2176300200057 2.6000E+00 1.7850E+00 6.2000E-02 2176300200058 2.7000E+00 1.8080E+00 6.3000E-02 2176300200059 2.8000E+00 1.8450E+00 6.4000E-02 2176300200060 2.9000E+00 1.8030E+00 6.3000E-02 2176300200061 3.0000E+00 1.9360E+00 6.8000E-02 2176300200062 3.1000E+00 1.8230E+00 6.4000E-02 2176300200063 3.2000E+00 1.8900E+00 6.6000E-02 2176300200064 3.2000E+00 1.8540E+00 6.5000E-02 2176300200065 3.4000E+00 1.7970E+00 6.3000E-02 2176300200066 3.5000E+00 1.8540E+00 6.5000E-02 2176300200067 3.6000E+00 1.8250E+00 6.4000E-02 2176300200068 3.7000E+00 1.7560E+00 6.2000E-02 2176300200069 3.8000E+00 1.8000E+00 6.3000E-02 2176300200070 3.9000E+00 1.8400E+00 6.4000E-02 2176300200071 3.9400E+00 1.9070E+00 7.1000E-02 2176300200072 4.0000E+00 1.9110E+00 6.7000E-02 2176300200073 4.2200E+00 2.0140E+00 7.5000E-02 2176300200074 4.4900E+00 1.8880E+00 7.0000E-02 2176300200075 4.7500E+00 1.7900E+00 6.7000E-02 2176300200076 4.9900E+00 2.0170E+00 7.5000E-02 2176300200077 5.2200E+00 1.9200E+00 7.2000E-02 2176300200078 5.4500E+00 1.8610E+00 7.0000E-02 2176300200079 5.6700E+00 1.9860E+00 7.4000E-02 2176300200080 5.8900E+00 1.8620E+00 7.0000E-02 2176300200081 6.1100E+00 2.1810E+00 7.9000E-02 2176300200082 6.3300E+00 2.2340E+00 8.1000E-02 2176300200083 6.5400E+00 1.8210E+00 6.6000E-02 2176300200084 6.7500E+00 1.8280E+00 6.6000E-02 2176300200085 6.9600E+00 1.6480E+00 5.9000E-02 2176300200086 7.1600E+00 1.7200E+00 6.2000E-02 2176300200087 7.3700E+00 1.6720E+00 6.0000E-02 2176300200088 7.5700E+00 1.6020E+00 5.8000E-02 2176300200089 7.7700E+00 1.5440E+00 5.6000E-02 2176300200090 7.9700E+00 1.5590E+00 5.6000E-02 2176300200091 7.9700E+00 1.5810E+00 5.7000E-02 2176300200092 8.1700E+00 1.5740E+00 5.7000E-02 2176300200093 8.3700E+00 1.5580E+00 5.6000E-02 2176300200094 8.5700E+00 1.5860E+00 5.7000E-02 2176300200095 8.7700E+00 1.6290E+00 5.9000E-02 2176300200096 8.9600E+00 1.6480E+00 5.9000E-02 2176300200097 9.1600E+00 1.5140E+00 5.5000E-02 2176300200098 9.3600E+00 1.5080E+00 5.4000E-02 2176300200099 9.5500E+00 1.6170E+00 5.8000E-02 2176300200100 9.7500E+00 1.6530E+00 6.0000E-02 2176300200101 9.9400E+00 1.6300E+00 5.9000E-02 2176300200102 ENDDATA 91 0 2176300200103 ENDSUBENT 102 0 2176300299999 ENDENTRY 2 0 2176399999999