ENTRY 21854 19830801 00002185400000001 SUBENT 21854001 19830801 00002185400100001 BIB 16 102 2185400100002 INSTITUTE (2ZZZGEL) EXPERIMENTAL SITE. H.L. 2185400100003 (2GERJUL) R.W.,S.M.Q. 2185400100004 REFERENCE (C,82ANTWER,,349,8209) MAIN REFERENCE. 2185400100005 (P,INDC(EUR)-15,19,8203) 2185400100006 AUTHOR (H.LISKIEN,R.WOELFE,S.M.QAIM) 2185400100007 TITLE -DETERMINATION OF LI-7(N,N'T)HE-4 CROSS SECTIONS. 2185400100008 FACILITY (VDG ) 7 MV VAN DE GRAAFF AT GEEL. 2185400100009 INC-SOURCE (D-D ) FOR NEUTRON ENERGY RANGE 5 TO 8 MEV 2185400100010 (D-T ) FOR NEUTRON ENERGY RANGE 13 TO 16 MEV. 2185400100011 TITANIUM OCCLUDED TARGETS ON 0.3 MILLI-M SILVER 2185400100012 BACKINGS. 2185400100013 -ABOUT 2 MILLI-G PER CM2 D-TI BOMBARDED BY DEUTERON 2185400100014 CURRENTS OF BETWEEN 8 AND 10 MICRO-AMP. 2185400100015 SAMPLE IRRADIATION TIME VARIED FROM 28 TO 53 HOURS. 2185400100016 -ABOUT 1 MILLI-G PER CM2 T-TI BOMBARDED BY A DEUTERON 2185400100017 CURRENT OF 25 MICRO-AMP. 2185400100018 SAMPLE IRRADIATION TIME 160 HOURS. 2185400100019 SAMPLE .LITHIUM ENRICHED IN LI-7 TO 99.99 +/- 0.01 ATOMS 2185400100020 PER CENT. NOMINAL DIMENSIONS- 20 MILLI-M DIAMETER 2185400100021 4 MILLI-M THICK. TYPICAL WEIGHT- 660 MILLI-G WITH A 2185400100022 VARIATION +/- 20 MILLI-G. 2185400100023 .SAMPLES WERE ETCHED WITH METHANOL AND ENCAPSULATED IN 2185400100024 0.25 MILLI-M THICK ALUMINIUM CONTAINER. 2185400100025 METHOD (ACTIV) TRITIUM EXTRACTED FROM IRRADIATED SAMPLES 2185400100026 AND ITS ACTIVITY DETERMINED. 2185400100027 DETECTOR (PROPC) GAS PROPORTIONAL COUNTER 2185400100028 .THE NEUTRON FLUX WAS MONITORED WITH A PROTON RECOIL 2185400100029 TELESCOPE DESCRIBED IN H.LISKIEN, PROC. SYMP. NEUTRON 2185400100030 STANDARDS AND FLUX NORMALIZATION, ARGONNE PAGE 343 2185400100031 (1970) 2185400100032 DECAY-DATA (1-H-3,12.3YR) 2185400100033 MONITOR (1-H-1(N,EL)1-H-1,,DA) NEUTRON-PROTON SCATTERING CROSS 2185400100034 SECTION AT 180 DEGREES. DATA TAKEN FROM J.C.HOPKINS 2185400100035 (1971). 2185400100036 PART-DET (B- ) BETA MINUS FROM TRITIUM DECAY. 2185400100037 STATUS .DATA TAKEN FROM MAIN REFERENCE. 2185400100038 HISTORY (830504C) A.P.T. 2185400100039 (830801E) 2185400100040 CORRECTION .TRITIUM PRODUCTION BY FAST NEUTRONS ON LI-6 MAY BE 2185400100041 NEGLECTED DUE TO THE HIGH ENRICHMENT OF THE SAMPLE. 2185400100042 THE EFFECT OF EPITHEMAL AND THERMAL NEUTRONS WAS 2185400100043 SHOWN TO BE ALSO NEGLIGIBLE BY IRRADIATING ADDITIONAL 2185400100044 LITHIUM SAMPLES ( ENRICHED TO 95.7 +/- 0.5 PER CENT ) 2185400100045 AT THREE NEUTRON ENERGIES - 5.23 6.49 AND 7.73 MEV. 2185400100046 .FOR THE D-D NEUTRON SOURCE, THE FLUX AT THE POSITION 2185400100047 OF THE HYDROGEN RADIATOR WAS CORRECTED FOR THE 2185400100048 TRANSMISSION OF THE SAMPLE. THIS WAS CALULATED FROM 2185400100049 THE LI-7 TOTAL CROSS SECTION, BUT WAS ALSO VERIFIED 2185400100050 EXPERIMENTALLY AT THREE NEUTRON ENERGIES USING A 2185400100051 SPARE LITHIUM SAMPLE. 2185400100052 .DURING SOME OF THE LONG IRRADIATION RUNS THE DATA 2185400100053 ACQUISITION OF THE PROTON RECOIL COUNTER WAS 2185400100054 INTERRUPTED BY ACCIDENT AND THE FLUX DURING THESE 2185400100055 INTERRUPTIONS HAD TO BE CALCULATED FROM THE ION BEAM 2185400100056 CHARGE ASSUMING PROPORTIONALITY BETWEEN CHARGE AND 2185400100057 NEUTRON PRODUCTION. 2185400100058 .FROM THE FLUX AT THE POSITION OF THE RADIATOR FOIL 2185400100059 THE FLUX AVERAGED OVER THE SAMPLE VOLUME WAS 2185400100060 DETERMINED TAKING INTO ACCOUNT THE GEOMETRY AND THE 2185400100061 ANGULAR DISTRIBUTION OF THE SOURCE NEUTRONS. 2185400100062 CORRECTIONS FOR NEUTRON SCATTERING AND ABSORPTION 2185400100063 WITHIN THE SAMPLE WERE PERFORMED. 2185400100064 .THE SPECTRUM OF SECONDARY NEUTRONS WAS DETERMINED 2185400100065 WITH A CALIBRATED NE-213 TOF SPECTROMETER AND WAS 2185400100066 FOUND TO BE CONSISTENT WITH RESULTS WHICH WERE 2185400100067 DEDUCED FROM THE LOW ENERGY TAIL OF THE OBSERVED 2185400100068 PROTON RECOIL SPECTRA. THE EFFECT OF THESE 2185400100069 SECONDARY NEUTRONS ON THE TRITIUM BREEDING CROSS 2185400100070 SECTION IS ESSENTIALLY ZERO BELOW 6.5 MEV PRIMARY 2185400100071 NEUTRON ENERGY AND INCREASES TO ABOUT 3.5 PER CENT 2185400100072 AT 8 MEV. 2185400100073 ERR-ANALYS (EN-ERR) UNCERTAINTY IN INCIDENT NEUTRON ENERGY IS 2185400100074 DUE TO UNCERTAINTIES IN - 2185400100075 DEUTERON ENERGY 2185400100076 TARGET THICKNESS 2185400100077 STOPPING POWER OF TARGET MATERIAL FOR 2185400100078 DEUTERONS 2185400100079 IRRADIATION ANGLE 2185400100080 THE QUOTED ERROR COVERS THE FULL RANGE OF THE 2185400100081 SPECTRUM SEEN BY THE SAMPLE. 2185400100082 (ERR-T) TOTAL ERROR ( ONE SIGMA ) OBTAINED BY QUADRATIC2185400100083 SUMMATION OF THE FOLLOWING CONTRIBUTIONS. 2185400100084 ( TYPICAL VALUES FOR THE D-D AND D-T SOURCES 2185400100085 ARE GIVEN IN PER CENT ). 2185400100086 ORIGIN D-D D-2185400100087 ------ --- --2185400100088 SAMPLE WEIGHT 0.5 0.2185400100089 ISOTOPIC SAMPLE COMPOSITION 0.1 0.2185400100090 EXTERNAL GEOMETRY 2.9 2.0-2.2185400100091 EFFECT OF SPURIOUS NEUTRONS 0.1-1.2 0.2185400100092 SCATTERING WITHIN THE SAMPLE 1.0 1.2185400100093 INTERNAL TELESCOPE GEOMETRY 1.3 1.2185400100094 HYDROGEN CONTENTS OF RADIATORS 1.5 1.2185400100095 PROTON RECOILS 1.0-3.0 1.2185400100096 N-P SCATTERING CROSS SECTION 1.0-1.2 2.2185400100097 SAMPLE TRANSMISSION 0.5 -2185400100098 ANGULAR DISTRIBUTION OF SOURCE 0.1 3.2185400100099 FLUX INTERPOLATION 0.0-2.6 -2185400100100 TRITIUM EXTRACTIION 2.0 2.2185400100101 CALIBRATION OF TRITIUM COUNTER 3.0 3.2185400100102 TRITIUM COUNTING 0.8-4.1 0.2185400100103 TRITIUM HALF LIFE 0.2 0.2185400100104 ENDBIB 102 0 2185400100105 NOCOMMON 0 0 2185400100106 ENDSUBENT 105 0 2185400199999 SUBENT 21854002 19830801 00002185400200001 BIB 3 4 2185400200002 REACTION (3-LI-7(N,N+T)2-HE-4,,SIG) 2185400200003 STATUS .TABLE 1 2185400200004 HISTORY (830504C) A.P.T. 2185400200005 (830801E) 2185400200006 ENDBIB 4 0 2185400200007 NOCOMMON 0 0 2185400200008 DATA 4 26 2185400200009 EN EN-ERR DATA ERR-T 2185400200010 MEV MEV MB MB 2185400200011 4.9900E+00 2.3000E-01 9.5000E+01 6.0000E+00 2185400200012 5.2300E+00 2.4000E-01 1.3700E+02 1.0000E+01 2185400200013 5.3900E+00 1.8000E-01 2.0000E+02 1.2000E+01 2185400200014 5.4900E+00 1.8000E-01 2.6900E+02 1.6000E+01 2185400200015 5.6100E+00 1.7000E-01 2.9700E+02 2.0000E+01 2185400200016 5.7400E+00 1.6000E-01 3.1600E+02 1.8000E+01 2185400200017 5.7400E+00 1.6000E-01 3.9900E+02 2.3000E+01 2185400200018 5.9900E+00 1.6000E-01 3.5200E+02 2.1000E+01 2185400200019 6.2300E+00 1.5000E-01 3.6900E+02 2.3000E+01 2185400200020 6.4900E+00 1.8000E-01 3.6100E+02 2.1000E+01 2185400200021 6.7300E+00 1.4000E-01 3.5900E+02 2.2000E+01 2185400200022 6.9800E+00 1.4000E-01 3.6700E+02 2.4000E+01 2185400200023 7.2300E+00 1.3000E-01 3.6900E+02 2.4000E+01 2185400200024 7.2300E+00 1.3000E-01 3.8800E+02 2.5000E+01 2185400200025 7.4800E+00 1.3000E-01 3.6400E+02 2.4000E+01 2185400200026 7.4800E+00 1.3000E-01 3.5200E+02 2.3000E+01 2185400200027 7.7300E+00 1.3000E-01 3.5100E+02 2.5000E+01 2185400200028 1.3010E+01 1.2000E-01 3.2200E+02 2.0000E+01 2185400200029 1.3510E+01 1.7000E-01 2.9200E+02 1.9000E+01 2185400200030 1.3770E+01 2.0000E-01 3.0600E+02 1.9000E+01 2185400200031 1.4020E+01 2.4000E-01 2.7100E+02 1.7000E+01 2185400200032 1.4770E+01 2.8000E-01 2.6300E+02 1.7000E+01 2185400200033 1.5030E+01 3.1000E-01 2.5600E+02 1.6000E+01 2185400200034 1.5270E+01 3.2000E-01 2.6900E+02 1.7000E+01 2185400200035 1.5780E+01 3.1000E-01 2.4600E+02 1.6000E+01 2185400200036 1.6030E+01 3.3000E-01 2.5300E+02 1.6000E+01 2185400200037 ENDDATA 28 0 2185400200038 ENDSUBENT 37 0 2185400299999 ENDENTRY 2 0 2185499999999