ENTRY 22146 19900917 00002214600000001 SUBENT 22146001 19900917 00002214600100001 BIB 17 51 2214600100002 REFERENCE (J,NIM/A,276,539,89) MAIN REFERENCE 2214600100003 (J,JP/G,9,1549,83) EXPERIMENTAL DETAILS 2214600100004 (J,JP/G,4,1783,78) 4PI BETA-GAMMA COUNTING TECHNIQUE 2214600100005 TITLE -THE ESCAPE OF RECOILS FROM NEUTRON-BOMBARDED FOILS. 2214600100006 AUTHOR (P.KOLKOWSKI,T.B.RYVES) 2214600100007 INSTITUTE (2UK NPL) 2214600100008 FACILITY .NPL SAMES ACCELERATOR PRODUCING 150 KEV DEUTERON BEAM.2214600100009 INC-SOURCE (D-T ) SOLID TI-T TARGET BACKED WITH THIN PURE AL, 2214600100010 PRODUCING 14.7 MEV NEUTRONS. 2214600100011 METHOD (ACTIV) 2214600100012 (BGCT ) 4PI BETA-GAMMA COINCIDENCE 2214600100013 (REC ) DIRECT MEASUREMENT OF 24-NA RECOILS COLLECTED 2214600100014 IN POLYTHENE 'CATCHER' FOILS WERE COMPARED WITH THE 2214600100015 INCREASE IN 24-NA ESCAPE PROBABILITY WITH DECREASING 2214600100016 FOIL THICKNESS AND WITH CALCULATION. 2214600100017 DETECTOR (COIN,PROPC,NAICR) 4PI BETA-GAMMA ARGON METHANE 2214600100018 PROPORTIONAL COUNTING IN COINCIDENCE WITH 2 NAI(TL) 2214600100019 GAMMA DETECTORS. 2214600100020 (GE-IN) TO ASSAY GAMMAS OF 24-NA IN 'CATCHER' FOILS. 2214600100021 PART-DET (B ) BETAS 2214600100022 (DG ) DECAY GAMMAS 2214600100023 MONITOR (26-FE-56(N,P)25-MN-56,,SIG) 2214600100024 DECAY-MON (25-MN-56,,B-) 2214600100025 MONIT-REF (,,R,EUR-11912-EN,90) 2214600100026 SAMPLE .THIN MG FOILS OF 2 TO 90 MG/CM-SQ AND 2.54 CM DIAMETER2214600100027 WITH 99.99% PURITY SANDWICHED BETWEEN STANDARD FE 2214600100028 FOILS OF 80 MG/CM-SQ AND 2.54 CM DIAMETER WITH 99.99% 2214600100029 PURITY. IRRADIATION AT 6 TO 10 CM FROM TARGET AT 0 DEG2214600100030 TO THE BEAM. THE RECOILING 24-NA NUCLEI WERE COLLECTED2214600100031 ON POLYTHENE 'CATCHER' FOILS. 2214600100032 CORRECTION .THE USE OF THE FE-MG-FE SANDWICH IN THE SAMPLE REMOVES2214600100033 THE NECESSITY TO MEASURE THE PRECISE DISTANCE FROM THE2214600100034 TARGET AND ALMOST ELIMINATES THE CORRECTION FOR 2214600100035 NEUTRON SCATTERING IN THE FOILS. THE SMALL 'K' 2214600100036 CORRECTION FOR 24-NA, WHICH COMBINES THE EFFECTS DUE 2214600100037 TO THE EFFICIENCY OF THE BETA COUNTER TO GAMMA RAYS 2214600100038 AND THE COMPLEX DECAY SCHEME OF THE ISOTOPE, WAS TAKEN2214600100039 FROM JP/G,4,1783,1978. 2214600100040 ERR-ANALYS (DATA-ERR) 1 SIGMA UNCERTAINTIES: 2214600100041 REFERENCE CROSS SECTION 0.5% 2214600100042 4PI BETA-GAMMA COUNTING 24-NA 0.6% 2214600100043 56-MN 0.6% 2214600100044 'K' CORRECTIONS 0.5% 2214600100045 EXTRAPOLATION TO INTERCEPT IN 1.3% 2214600100046 PLOT OF CROSS SECTION VERSUS 2214600100047 RECIPROCAL FOIL THICKNESS 2214600100048 NEUTRON ENERGY (+-30 KEV) 0.5% 2214600100049 TOTAL (QUADRATIC SUM) 1.8% 2214600100050 STATUS .DATA TAKEN FROM MAIN REFERENCE 2214600100051 HISTORY (900607C) S.W. 2214600100052 (900917E) 2214600100053 ENDBIB 51 0 2214600100054 COMMON 2 3 2214600100055 MONIT MONIT-ERR 2214600100056 MB MB 2214600100057 1.0840E+02 5.0000E-01 2214600100058 ENDCOMMON 3 0 2214600100059 ENDSUBENT 58 0 2214600199999 SUBENT 22146002 19900917 00002214600200001 BIB 3 5 2214600200002 REACTION (12-MG-24(N,P)11-NA-24,,SIG) 2214600200003 STATUS .DATA FROM FIG. 1, INTERCEPT OF PLOT OF MEASURED CROSS 2214600200004 SECTION VERSUS RECIPROCAL FOIL THICKNESS. 2214600200005 HISTORY (900607C) S.W. 2214600200006 (900917E) 2214600200007 ENDBIB 5 0 2214600200008 NOCOMMON 0 0 2214600200009 DATA 4 1 2214600200010 EN EN-ERR DATA DATA-ERR 2214600200011 MEV MEV MB MB 2214600200012 1.4700E+01 3.0000E-02 1.7600E+02 3.0000E+00 2214600200013 ENDDATA 3 0 2214600200014 ENDSUBENT 13 0 2214600299999 ENDENTRY 2 0 2214699999999