ENTRY 20362 19840109 00002036200000001 SUBENT 20362001 19840109 00002036200100001 BIB 13 55 2036200100002 INSTITUTE (2GERKFK) 2036200100003 REFERENCE (J,NSE,33,24,6807) 2036200100004 AUTHOR (H.O.MENLOVE,W.P.POENITZ) 2036200100005 TITLE -ABSOLUTE RADIATIVE CAPTURE CROSS SECTION 2036200100006 FOR FAST NEUTRONS IN U-238.- 2036200100007 FACILITY (VDG ) PULSED 3 MV VAN DE GRAAFF ACCELERATOR 2036200100008 INC-SOURCE (P-LI7) THIN TARGET 2036200100009 SAMPLE .SHAPE DETERMINATION, METALLIC DISK, 0.1 CM THICK, 9 CM2036200100010 DIAMETER, DEPLETED TO 0.4 PERCENT U-235. 2036200100011 .ABSOLUTE 30 KEV VALUE, 2 METALLIC FOILS, 0.0066 CM 2036200100012 THICK, 1.1 CM DIAMETER, DEPLETED TO 0.22 PERCENT U-2352036200100013 METHOD .CROSS SECTION SHAPE WAS DETERMINED BY RECORDING 2036200100014 RESPONSE OF SCINTILLATOR TANK TO PROMPT CAPTURE GAMMAS2036200100015 RELATIVE TO GREY NEUTRON DETECTOR COUNTS. USE OF 2036200100016 MONOENERGETIC NEUTRONS WAS COMBINED WITH 2036200100017 (TOF ) TIME-OF-FLIGHT METHOD TO DETERMINE BACKGROUND, 2036200100018 NEUTRON ENERGY AND ITS SPREAD. 1.5 M FLIGHT PATH. 2036200100019 .ABSOLUTE CROSS SECTION WAS MEASURED AT 30 KEV WITH 2036200100020 KINEMATICALLY COLLIMATED NEUTRONS AS FOLLOWS. 2036200100021 (ACTIV) BE-7 ACTIVITY OF LI TARGET GAVE NUMBER OF NEU- 2036200100022 TRONS PRODUCED, NP-239 ACTIVITY OF U SAMPLE GAVE NUM- 2036200100023 BER OF CAPTURE EVENTS. THE LATTER WAS MEASURED BY 2 2036200100024 METHODS. RESULT WAS ALSO CHECKED AGAINST AU(N,GAMMA). 2036200100025 DETECTOR (STANK) 800L SCINTILLATOR TANK AS CAPTURE DETECTOR, 2036200100026 (MTANK) GREY DETECTOR FOR FLUX SHAPE, 2036200100027 (GELI ) FOR NP-239 278 KEV GAMMA RAY, 2036200100028 (NAICR) FOR NP-239 106 KEV GAMMA RAY IN COINCID. WITH 2036200100029 X-RAY (2 CRYSTALS) AND FOR BE-7 478 KEV AND AU-197 2036200100030 411 KEV GAMMA RAYS (1 CRYSTAL). GELI AND NAI DETECTORS2036200100031 WERE CALIBRATED WITH AM-243 SOURCE OF KNOWN ACTIVITY. 2036200100032 MONITOR (79-AU-197(N,G)79-AU-198,,SIG) 2036200100033 .THE 30 KEV MEASUREMENT RELATIVE TO AU(N,GAMMA) YIELDS 2036200100034 - 492+-17 MB FOR U, IF 599+-12 MB IS TAKEN FOR AU. 2036200100035 - 473+-15 MB FOR U IS OBTAINED FROM THE ASSOCIATED 2036200100036 BE-7 ACTIVITY. HENCE THE SHAPE DATA WERE NORMALIZED TO2036200100037 THE AVERAGE, 2036200100038 - 479+-14 MB AT 30 KEV. 2036200100039 HISTORY (740522C) 2036200100040 (740929E) 2036200100041 CORRECTION .NUMEROUS CORRECTIONS ARE LISTED IN NUCL.SCI.ENG., 2036200100042 33(1968)24. 2036200100043 ERR-ANALYS .MAIN SHAPE UNCERTAINTIES ARE 2036200100044 1.5-4.5 PERCENT FROM TANK COUNT STATISTICS, 2036200100045 0.0-4.0 PERCENT FROM ENERGY DEPENDENCE OF SPECTRUM 2036200100046 - FRACTION ABOVE TANK BIAS, 2036200100047 0.0-3.7 PERCENT FROM ENERGY DEP. OF TANK EFFICIENCY, 2036200100048 0.0-2.0 PERCENT FROM ANISOTROPY EFFECTS IN GREY DET., 2036200100049 0.0-2.0 PERCENT FROM LOW-EN. NEUTRONS IN GREY DET. 2036200100050 OTHERS ARE SPECIFIED IN NUCL.SCI.ENG.,33(1968)24. 2036200100051 .MAIN UNCERTAINTIES IN 30 KEV VALUE ARE 2036200100052 - 1.7 PERC. FROM ABSOL. CALIBR. OF NP-237 COUNTER, 2036200100053 - 1.4 PERC. FROM ABSOL. CALIBR. OF BE-7 COUNTER, 2036200100054 - 2.0 PERC. FROM 30 KEV AU CAPTURE CROSS SECTION, 2036200100055 - 1.6 PERC. FROM BE-7 GAMMA RAYS PER DISINTEGRATION. 2036200100056 OTHERS ARE LISTED IN NUCL.SCI.ENG.,33(1968)24. 2036200100057 ENDBIB 55 0 2036200100058 NOCOMMON 0 0 2036200100059 ENDSUBENT 58 0 2036200199999 SUBENT 20362002 19840109 00002036200200001 BIB 3 4 2036200200002 REACTION (92-U-238(N,G)92-U-239,,SIG) 2036200200003 STATUS .DATA TAKEN FROM NUCL.SCI.ENG.,33(1968)24. 2036200200004 HISTORY (740522C) 2036200200005 (740929E) 2036200200006 ENDBIB 4 0 2036200200007 NOCOMMON 0 0 2036200200008 DATA 5 9 2036200200009 EN EN-RSL EN-ERR DATA DATA-ERR 2036200200010 MEV PER-CENT MEV B B 2036200200011 2.4400E-02 2.7000E+01 9.0000E-04 5.1600E-01 2.7000E-02 2036200200012 3.0000E-02 5.0000E+01 1.5000E-03 4.7900E-01 1.4000E-02 2036200200013 4.3800E-02 3.7000E+01 1.3000E-03 4.0400E-01 1.9000E-02 2036200200014 6.3300E-02 2.0000E+01 7.0000E-04 3.0200E-01 1.4000E-02 2036200200015 9.7300E-02 2.1000E+01 2.8000E-03 2.0100E-01 1.1000E-02 2036200200016 1.5700E-01 1.8000E+01 3.0000E-03 1.5300E-01 9.0000E-03 2036200200017 2.6400E-01 1.7000E+01 3.0000E-03 1.2600E-01 9.0000E-03 2036200200018 3.7300E-01 1.6000E+01 1.2000E-02 1.2300E-01 1.1000E-02 2036200200019 5.0300E-01 1.8000E+01 1.2000E-02 1.1000E-01 1.0000E-02 2036200200020 ENDDATA 11 0 2036200200021 ENDSUBENT 20 0 2036200299999 ENDENTRY 2 0 2036299999999