ENTRY 22256 19961128 00002225600000001 SUBENT 22256001 19961128 00002225600100001 BIB 18 86 2225600100002 INSTITUTE (2GERKFK) 2225600100003 REFERENCE (J,AJ,389,784,92) 2225600100004 AUTHOR (H.BEER,G.WALTER,F.KAEPPELER) 2225600100005 TITLE -MEASUREMENT OF THE SE-76(N,G) CAPTURE CROSS SECTION 2225600100006 AND PHENOMENOLOGICAL S-PROCESS STUDIES. THE WEAK COM- 2225600100007 PONENT. 2225600100008 FACILITY (VDG ) THE KARLSRUHE 500 KHZ PULSED 3.75 MV VAN DE 2225600100009 GRAAFF ACCELERATOR WAS USED. 2225600100010 INC-SOURCE (P-LI7) THE NEUTRON BEAM WAS COLLIMATED. 2225600100011 SAMPLE .THE SE-76 AND AU-197 SAMPLES CONSISTED OF METAL FOILS,2225600100012 25 MM IN DIAMETER AND WEIGHING 4.9509 GRAMS AND 4.642 2225600100013 GRAMS, RESPECTIVELY. THE SE SAMPLE HAD THE FOLLOWING 2225600100014 ISOTOPIC COMPOSITION 2225600100015 . 2225600100016 ISOTOPE PERCENT 2225600100017 . ------- ------- 2225600100018 74 1.2 2225600100019 76 98.5+/-0.2 2225600100020 77 0.2 2225600100021 78 0.03 2225600100022 80 0.01 2225600100023 82 .LT. 0.02 2225600100024 ................................................. 2225600100025 THE AU SAMPLE HAD A NATURAL ISOTOPIC COMPOSITION. THE 2225600100026 GRAPHITE SAMPLE WAS A DISK WITH THE SAME DIAMETER, 2225600100027 HAVING A WEIGHT OF 1.036 GRAMS AND A NATURAL ISOTOPIC 2225600100028 COMPOSITION. THE SAMPLES WERE POSITIONED ALTERNATIVELY2225600100029 INTO THE NEUTRON BEAM TO AVERAGE OVER INTENSITY FLUC- 2225600100030 TUATIONS. 2225600100031 METHOD (TOF ) NEUTRON ENERGIES WERE MEASURED BY TIME-OF- 2225600100032 FLIGHT. CAPTURE EVENTS WERE REGISTERED BY DETECTING 2225600100033 THE GAMMA-RAY CASCADES OF THE EXCITED COMPOUND NUC- 2225600100034 LEUS. THE CAPTURE CROSS SECTION OF SE-76 WAS MEASURED 2225600100035 RELATIVE TO AU-197. 2225600100036 DETECTOR (SCIN ) THE GAMMA-RAY CASCADES OF THE EXCITED COMPOUND 2225600100037 NUCLEUI WERE DETECTED WITH TWO C6D6 LIQUID SCINTIL- 2225600100038 LATION COUNTERS, WELL SHIELDED TO REDUCE THE BACK- 2225600100039 GROUND COUNT RATE. FOUR DIFFERENT TOF SPECTRA WERE 2225600100040 RECORDED, /1/ SE-76, /2/ AU-197, /3/ A SPECTRUM WITH- 2225600100041 OUT SAMPLE TO OBTAIN THE SAMPLE INDEPENDENT BACK- 2225600100042 GROUND, AND /4/ A GRAPHITE SPECTRUM TO SIMULATE THE 2225600100043 BACKGROUND SPECTRUM FROM SAMPLE SCATTERED NEUTRONS. 2225600100044 AS THE EFFICIENCY OF THE DETECTORS WERE A NON-LINEAR 2225600100045 FUNCTION OF GAMMA-RAY ENERGY, A GAMMA-RAY WEIGHTING 2225600100046 TECHNIQUE WAS APPLIED. 2225600100047 .A NEUTRON COUNTER, USED TO MONITOR THE FLUX, WAS 2225600100048 PLACED AT 90 DEGREES TO THE BEAM AXIS. 2225600100049 PART-DET (G ) 2225600100050 ANALYSIS .THE DATUM GIVEN WAS OBTAINED BY INTEGRATING THE 2225600100051 MEASURED EXCITATION FUNCTION OVER A MAXWELL-BOLTZMANN 2225600100052 DISTRIBUTION WITH TEMPERATURE KT. THE EXPERIMENTAL 2225600100053 DATA WERE EXTRAPOLATED BEYOND 200 KEV ASSUMING A 1/E 2225600100054 DEPENDENCE. THE LOWER INTEGRATION LIMIT WAS EXTENDED 2225600100055 FROM 3 KEV TO THERMAL ENERGY BY TAKING INTO ACCOUNT 2225600100056 THE CONTRIBUTION FROM RESOLVED RESONANCES QUOTED BY 2225600100057 MUGHABGAB ET AL. 2225600100058 MONITOR (79-AU-197(N,G)79-AU-198,,SIG) 2225600100059 MONIT-REF (,MACKLIN,W,MACKLIN,82) THE STANDARD GOLD CAPTURE 2225600100060 CROSS SECTION AS A FUNCTION OF ENERGY WAS TAKEN FROM 2225600100061 MACKLIN AND 2225600100062 (,RATYNSKI+,J,PR/C,37,595,88) NORMALIZED TO THE MORE 2225600100063 PRECISE CROSS SECTION DATA POINT AT KT = 25 KEV FROM 2225600100064 RATYNSKI AND KAEPPELER. 2225600100065 CORRECTION .THE DATA WERE CORRECTED FOR NEUTRON MULTIPLE SCATTER- 2225600100066 ING AND SELF-SHIELDING, AND FOR GAMMA-RAY SELF-ABSORP-2225600100067 TION IN THE SAMPLES. 2225600100068 ERR-ANALYS (ERR-T) THE TOTAL ERROR GIVEN INCLUDES THE FOLLOWING 2225600100069 CONTRIBUTIONS 2225600100070 (ERR-1) GOLD STANDARD ERROR 1.5 222225600100071 (ERR-2) PULSE HEIGHT WEIGHTING TECHNIQUE ERROR 3 2225600100072 (ERR-3) NEUTRON MULTIPLE SCATTERING AND 2225600100073 SELF-SHIELDING ERROR 1 2225600100074 (ERR-4) MAXIMUM GAMMA-RAY SELF-ABSORPTION ERROR 1 2225600100075 (ERR-5) TIME-DEPENDENT BACKGROUND 2225600100076 CORRECTION ERROR 3 2225600100077 (ERR-6) ISOTOPE IMPURITIES ERROR 0.4 2225600100078 . 2225600100079 COMMENT .THE MEASURED EXCITATION FUNCTION FROM 3 TO 200 KEV IS 2225600100080 GIVEN IN FIG. 2 OF THE MAIN REF. 2225600100081 STATUS .DATA TAKEN FROM MAIN REF. 2225600100082 HISTORY (940109C) N.O. 2225600100083 (950420E) 2225600100084 (961128A) + + CORRECTED BY S.MAEV 2225600100085 -T FROM MONITOR CODE DELETED 2225600100086 MONIT-REF CODE CORRECTED 2225600100087 ERROR STRUCTURE GIVEN IN RETRIEVABLE FORM + + 2225600100088 ENDBIB 86 0 2225600100089 COMMON 6 3 2225600100090 ERR-1 ERR-2 ERR-3 ERR-4 ERR-5 ERR-6 2225600100091 PER-CENT PER-CENT PER-CENT PER-CENT PER-CENT PER-CENT 2225600100092 1.5 3. 1. 1. 3. 0.4 2225600100093 ENDCOMMON 3 0 2225600100094 ENDSUBENT 93 0 2225600199999 SUBENT 22256002 19961128 00002225600200001 BIB 3 6 2225600200002 REACTION (34-SE-76(N,G)34-SE-77,,SIG,,MXW) 2225600200003 STATUS .DATA TAKEN FROM MAIN REF. 2225600200004 HISTORY (940109C) N.O. 2225600200005 (950420E) 2225600200006 (961128U) * * -T DELETED IN REACTION SF4 2225600200007 DATA-ERR CHANGED TO ERR-T * * 2225600200008 ENDBIB 6 0 2225600200009 NOCOMMON 0 0 2225600200010 DATA 3 1 2225600200011 KT DATA ERR-T 2225600200012 KEV MB MB 2225600200013 3.0000E+01 1.6400E+02 8.0000E+00 2225600200014 ENDDATA 3 0 2225600200015 ENDSUBENT 14 0 2225600299999 ENDENTRY 2 0 2225699999999