ENTRY RWK87 0 RWK87 0 1 SUBENT RWK87 1 0 RWK87 1 1 BIB 12 58 RWK87 1 2 INSTITUTE (SFHLS) RWK87 1 3 REFERENCE (J,NIM/B,28,199,1987) RWK87 1 4 AUTHORS (J.RAISANEN,T.WITTING,J.KEINONEN) RWK87 1 5 TITLE ABSOLUTE THICK-TARGET GAMMA-RAY YIELDS FOR ELEMENTAL RWK87 1 6 ANALYSIS BY 7 AND 9 MEV PROTONS RWK87 1 7 FACILITY (VDG) 5-MV TANDEM VAN DE GRAAFF ACCELERATOR RWK87 1 8 EGP-10-11, PHYSICS DEPARTMENT, UNIVERSITY OF RWK87 1 9 HELSINKI, HELSINKI, FINLAND. RWK87 1 10 INC-PART (P) PROTONS RWK87 1 11 TARGETS INP THICK TARGET. PRESSED PELLET 1 MM THICK X RWK87 1 12 6 MM IN DIAMETER. RWK87 1 13 METHOD PROTON BEAMS WERE OBTAINED FROM THE 5-MV TANDEM RWK87 1 14 ACCELERATOR AT HELSINKI UNIVERSITY. GAMMA-RAYS RWK87 1 15 WERE DETECTED WITH A SHIELDED GE(LI) DETECTOR AT RWK87 1 16 55 DEGREES RELATIVE TO THE INCIDENT PROTON BEAM RWK87 1 17 IN ORDER TO MINIMIZE ANGULAR DISTRIBUTION EFFECTS. RWK87 1 18 UNCERTAINTIES DUE TO SMALL CHANGES IN SOLID ANGLE RWK87 1 19 OF THE DETECTOR FOR DIFFERENT TARGETS WERE KEPT TO RWK87 1 20 A MINIMUM BY THE USE OF A TARGET-TO-DETECTOR RWK87 1 21 DISTANCE OF 27 CM. THE ENERGY AND ABSOLUTE RWK87 1 22 EFFICIENCY OF THIS DETECTOR WAS DETERMINED USING RWK87 1 23 CALIBRATED SOURCES OF 60CO, 56CO, AND 152EU. RWK87 1 24 NEUTRONS WERE DETECTED WITH A BF3 COUNTER LOCATED RWK87 1 25 90 CM FROM THE TARGET. THE PROTON BEAM CURRENT WAS RWK87 1 26 ADJUSTED TO KEEP THE GAMMA-RAY COUNT RATE CONSTANT RWK87 1 27 AND THE DEAD TIME CORRECTION BELOW 1 PERCENT. THE RWK87 1 28 CURRENT VARIED BETWEEN 0.1 AND 20 NANOAMP. THE RWK87 1 29 CHARGE ON TARGET WAS RECORDED WITH AN ACCURATELY RWK87 1 30 CALIBRATED CURRENT INTEGRATOR AND CHARGE SUPPRESOR RWK87 1 31 ARRANGEMENT. THE ACCUMULATED CHARGE WAS IN THE RWK87 1 32 RANGE 0.07 TO 31 MICROCOULOMB. ATTENTION WAS RWK87 1 33 GIVEN TO A FEW GAMMA-RAYS FOR EACH TARGET THAT RWK87 1 34 OFFERED PROMISE FOR SAMPLE ASSAY PURPOSES. IN RWK87 1 35 GENERAL, ALL GAMMA-RAYS WITH ENERGIES BELOW 511 RWK87 1 36 KEV WERE EXCLUDED FROM CONSIDERATION. GENERALLY, RWK87 1 37 LOW-ENERGY GAMMA-RAYS WERE POORLY RESOLVED AND RWK87 1 38 THEIR YIELDS WERE HARD TO DETERMINE DUE SIGNIFICANT RWK87 1 39 ABSORPTION IN THE TARGET AND HOLDER. RWK87 1 40 DETECTOR (PROP) BF3 COUNTER NEUTRON DETECTOR. RWK87 1 41 (GELI) 80-CM**3 CANBERRA GE(LI) DETECTOR WITH A RWK87 1 42 RESOLUTION OF 1.9 KEV AT EG = 1.33 MEV AND AN RWK87 1 43 EFFICIENCY OF ABOUT 18 PERCENT. RWK87 1 44 MONITOR (CI) CURRENT INTEGRATOR. RWK87 1 45 CORRECTION DATA CORRECTED FOR RECORDING SYSTEM DEAD TIME, RWK87 1 46 GAMMA-RAY ABSORPTION EFFECTS, AND DETECTOR RWK87 1 47 EFFICIENCY. RWK87 1 48 ERR-ANALYS NO ERRORS ARE GIVEN. HOWEVER, IT WAS ESTIMATED RWK87 1 49 THAT THE ABSOLUTE GAMMA-RAY YIELD VALUES SHOULD RWK87 1 50 BE ACCURATE TO BETTER THAN 10 PERCENT. THE SOURCES RWK87 1 51 OF ERROR INCLUDED STOPPING POWER (2 PERCENT), GAMMA- RWK87 1 52 RAY INTENSITIES (2-5 PERCENT), AND ABSOLUTE GAMMA- RWK87 1 53 RAY DETECTOR EFFICIENCY (5 PERCENT). IN ORDER TO RWK87 1 54 STUDY POSSIBLE SYSTEMATIC EFFECTS, THE ELEMENTS RWK87 1 55 WERE INCLUDED IN VARIOUS COMPOUNDS. GENERALLY, THE RWK87 1 56 AGREEMENT FOR A PARTICULAR ELEMENT IN DIFFERENT RWK87 1 57 COMPOUNDS WAS BETTER THAN 20 PERCENT. THE DEVIATIONS RWK87 1 58 CAN BE EXPLAINED BY CHANGES IN TARGET STOICHIOMETRY RWK87 1 59 LEADING TO AN ERRONEOUS STOPPING POWER. RWK87 1 60 ENDBIB 58 RWK87 1 61 ENDSUBENT 1 RWK87 199999 SUBENT RWK87 2 0 RWK87 2 1 BIB 2 9 RWK87 2 2 REACTIONS A: 31P(P,P')31P RWK87 2 3 B: 31P(P,ALPHA)28SI RWK87 2 4 C: 31P(P,GAMMA)32S RWK87 2 5 COMMENTS ABSOLUTE THICK-TARGET GAMMA-RAY YIELDS ARE GIVEN FOR RWK87 2 6 A THICK INP TARGET. EP = INCIDENT PROTON ENERGY. RWK87 2 7 EG = CHARACTERISTIC GAMMA RAY. REACTION = SOURCE RWK87 2 8 REACTION FOR THE GAMMA RAY (A, B, C OR COMBINATION). RWK87 2 9 YLD = ABSOLUTE GAMMA-RAY YIELD. THE YIELD IS GIVEN RWK87 2 10 IN "UNIT". 1 UNIT = 1 COUNTS/MICROCOULOMB/STERADIAN. RWK87 2 11 ENDBIB 9 RWK87 2 12 DATA 4 6 RWK87 2 13 EP EG REACTION YLD RWK87 2 14 MEV KEV NO-DIM UNIT RWK87 2 15 7. 1266. A 9.7400E+07 RWK87 2 16 7. 1779. B 5.2200E+07 RWK87 2 17 7. 2230. A,C 7.0100E+07 RWK87 2 18 9. 1266. A 1.7400E+08 RWK87 2 19 9. 1779. B 8.1000E+07 RWK87 2 20 9. 2230. A,C 1.3300E+08 RWK87 2 21 ENDDATA 8 RWK87 2 22 ENDSUBENT 2 RWK87 299999 ENDENTRY 2 RWK879999999