ENTRY 21877 20110304 22262187700000001 SUBENT 21877001 20110304 22262187700100001 BIB 14 58 2187700100002 INSTITUTE (2UK HAR) 2187700100003 (2UK LON) J.G. 2187700100004 REFERENCE ((J,NP/A,419,497,1984)=(R,AERE-R-10842,198310)) 2187700100005 REL-REF (M,,G.D.James+,J,NIM,205,151,1983) 2187700100006 AUTHOR (G.D.James,D.B.Syme,J.Grainger) 2187700100007 TITLE -The fission cross-section of Th-228 near threshold- 2187700100008 FACILITY (VDG,2UK HAR) 6 MeV accelerator. 2187700100009 INC-SOURCE (P-LI7) Proton beam with a diameter of 2 mm on 2187700100010 a LiF target. 2187700100011 SAMPLE .The fissionable deposit is spread uniformly over 2187700100012 a circular area of 20 mm diam. The deposit is of 2187700100013 20 micro-g Th-228. the wall of the vacuum chamber, 2187700100014 on which the fission foil is attached, is 0.7 mm thick2187700100015 over an inner diameter of 100 mm to reduce scattering 2187700100016 corrections. 2187700100017 METHOD .The fission fragments were detected in a cylindrical 2187700100018 arrangement of 'Makrofol KG', which enabled their 2187700100019 spatial distribution to be determined after etching 2187700100020 and sparking under carefully controlled conditions. 2187700100021 DETECTOR .Consists of a cylindrical surface, 100 mm long and 2187700100022 200 mm diam, and a disc, 200 mm diam, of 'Makrofol KG'2187700100023 the axis of the Makrofol cylinder is set along the 2187700100024 proton beam direction. The detector and the fission 2187700100025 foil are housed in a cylindrical steel vacuum chamber.2187700100026 .The method to process the Makrofol sheets is 2187700100027 described in (J,NIM,205,151,1983) 2187700100028 ANALYSIS .Experimental runs are normalised to equal numbers of 2187700100029 incident neutrons by means of a long counter. 2187700100030 .An absolute determination of the fission cross 2187700100031 section of (370+-32) mb was determined at 1635 keV. 2187700100032 The rest of the cross section data are normalisations 2187700100033 to that value. 2187700100034 STATUS (TABLE).Data taken from table 2 in NP/A,419,497,1984 2187700100035 CORRECTION .For 2187700100036 - hole overlap on etched foils 2187700100037 - background 2187700100038 - fragment detection efficiency of foils 2187700100039 .in the determination of the absolute fission cross 2187700100040 section at 1.635 MeV corrections are made for 2187700100041 - presence of a low-energy component in the 2187700100042 Li-7(p,n) reaction. 2187700100043 - Neutrons scattered from parts of the experimental 2187700100044 equipment. 2187700100045 - Angular dependence of neutrons 2187700100046 - non-uniformity due to the plane geometry of the foil2187700100047 - the nominal angle (81 to 90 adeg) for which data are2187700100048 not recorded on assumption of fragment isotropy 2187700100049 - neutron scattered in the air between the n-source 2187700100050 and the long counter 2187700100051 HISTORY (19831125C) A.L. 2187700100052 (19840202E) 2187700100053 (19850213A) BL 2187700100054 (19850419E) 2187700100055 (20110304A) SD: Updated to new date formats,lower case.2187700100056 corrected according to last EXFOR rules and Dict. 2187700100057 SUBENT 002 divided in two (002,004). ERR-ANALYS 2187700100058 corrected according to description in the article. 2187700100059 REACTION in 003 corrected. STATUS moved to Subent 0012187700100060 ENDBIB 58 0 2187700100061 NOCOMMON 0 0 2187700100062 ENDSUBENT 61 0 2187700199999 SUBENT 21877002 20110626 22262187700200001 BIB 5 12 2187700200002 REACTION (90-TH-228(N,F),,SIG) 2187700200003 MONITOR (90-TH-228(N,F),,SIG) see Subent 004 2187700200004 ERR-ANALYS (ERR-T) A combination of 2187700200005 (MONIT-ERR) the error in the normalisation 2187700200006 (ERR-1) an error in the relative correction factor-1.7%2187700200007 - a statistical error. 2187700200008 STATUS (DEP,21877004) An absolute determination of the fission2187700200009 cross section at 1635 keV gave the value 370 +- 32 mb2187700200010 to which the data are normalised. 2187700200011 HISTORY (20110304A) SD: Cross-section that measured several 2187700200012 times and used for normalization for others moved to 2187700200013 Subent 004. 2187700200014 ENDBIB 12 0 2187700200015 COMMON 2 3 2187700200016 ERR-1 MONIT-ERR 2187700200017 PER-CENT PER-CENT 2187700200018 1.7 8.7 2187700200019 ENDCOMMON 3 0 2187700200020 DATA 4 40 2187700200021 EN EN-RSL DATA ERR-T 2187700200022 KEV KEV MB MB 2187700200023 3.5000E+02 1.9000E+01 5.0500E+01 5.5000E+00 2187700200024 3.7500E+02 2.2000E+01 3.0900E+01 3.0000E+00 2187700200025 3.9300E+02 2.9000E+01 3.6000E+01 3.7000E+00 2187700200026 4.0000E+02 2.6000E+01 2.9900E+01 4.1000E+00 2187700200027 4.2500E+02 2.5000E+01 1.6700E+01 2.0000E+00 2187700200028 4.4200E+02 1.6000E+01 3.2900E+01 2.8000E+00 2187700200029 4.5000E+02 3.7000E+01 4.8800E+01 3.7000E+00 2187700200030 4.7000E+02 2.5000E+01 4.4800E+01 3.2000E+00 2187700200031 5.0000E+02 3.1000E+01 3.7000E+01 1.9000E+00 2187700200032 5.3000E+02 2.6000E+01 2.5900E+01 1.9000E+00 2187700200033 5.4000E+02 3.7000E+01 2.3200E+01 1.5000E+00 2187700200034 5.6000E+02 2.8000E+01 2.5800E+01 1.4000E+00 2187700200035 5.9000E+02 2.7000E+01 2.7300E+01 1.9000E+00 2187700200036 6.2500E+02 2.4000E+01 2.3800E+01 2.5000E+00 2187700200037 6.5000E+02 2.4000E+01 8.9000E+00 1.1000E+00 2187700200038 6.6000E+02 3.6000E+01 2.5900E+01 1.6000E+00 2187700200039 7.0000E+02 3.6000E+01 5.7100E+01 3.0000E+00 2187700200040 7.2500E+02 2.5000E+01 1.3160E+02 8.5000E+00 2187700200041 7.4000E+02 3.6000E+01 1.8870E+02 9.7000E+00 2187700200042 7.5000E+02 2.3000E+01 2.2800E+02 1.2000E+01 2187700200043 7.7500E+02 2.7000E+01 1.9400E+02 1.4000E+01 2187700200044 7.8000E+02 3.6000E+01 1.9900E+02 1.0000E+01 2187700200045 8.0000E+02 2.5000E+01 9.1900E+01 6.7000E+00 2187700200046 8.2000E+02 3.6000E+01 1.6400E+02 9.0000E+00 2187700200047 8.2500E+02 2.7000E+01 1.4200E+02 9.7000E+00 2187700200048 8.6000E+02 3.6000E+01 1.7700E+02 1.1000E+01 2187700200049 9.0000E+02 3.3000E+01 2.3030E+02 8.4000E+00 2187700200050 9.2500E+02 2.0000E+01 3.4400E+02 1.3000E+01 2187700200051 9.5000E+02 2.2000E+01 3.1500E+02 1.9000E+01 2187700200052 9.7500E+02 2.5000E+01 3.3900E+02 2.3000E+01 2187700200053 9.9600E+02 1.6000E+01 3.3800E+02 1.9000E+01 2187700200054 1.0000E+03 1.5000E+01 3.5200E+02 2.3000E+01 2187700200055 1.0250E+03 2.5000E+01 3.3200E+02 2.1000E+01 2187700200056 1.0500E+03 1.4000E+01 3.4200E+02 2.2000E+01 2187700200057 1.0750E+03 2.5000E+01 3.3200E+02 1.9000E+01 2187700200058 1.1000E+03 2.1000E+01 3.3100E+02 1.5000E+01 2187700200059 1.1250E+03 2.8000E+01 2.5800E+02 1.6000E+01 2187700200060 1.1500E+03 2.2000E+01 2.6300E+02 1.2000E+01 2187700200061 1.1750E+03 2.2000E+01 2.5300E+02 1.6000E+01 2187700200062 1.2000E+03 2.5000E+01 3.0200E+02 1.8000E+01 2187700200063 ENDDATA 42 0 2187700200064 ENDSUBENT 63 0 2187700299999 SUBENT 21877003 20110626 22262187700300001 BIB 4 7 2187700300002 REACTION ((90-TH-228(N,F),,DA,FF)// 2187700300003 (90-TH-228(N,F),,DA,FF)) 2187700300004 COMMENT .Angular anisotropy ratio n(20-deg)/n(80-deg). 2187700300005 ERR-ANALYS (ERR-S) Uncertainties ascribed by standard 2187700300006 statistical procedures only. 2187700300007 HISTORY (20110304A) SD: REACTION code corrected: 2187700300008 90-TH-228(N,F),,DA,FF,REL => to ratio 2187700300009 ENDBIB 7 0 2187700300010 COMMON 2 3 2187700300011 ANG1 ANG2 2187700300012 ADEG ADEG 2187700300013 2.0000E+01 8.0000E+01 2187700300014 ENDCOMMON 3 0 2187700300015 DATA 4 22 2187700300016 EN EN-RSL DATA ERR-S 2187700300017 KEV KEV NO-DIM NO-DIM 2187700300018 3.5000E+02 1.9000E+01 8.5000E-01 1.5000E-01 2187700300019 3.7500E+02 2.2000E+01 3.2500E+00 1.3300E+00 2187700300020 4.2500E+02 2.5000E+01 2.1500E+00 8.0000E-01 2187700300021 4.5000E+02 3.7000E+01 1.7900E+00 3.1000E-01 2187700300022 5.0000E+02 3.1000E+01 1.5200E+00 7.0000E-02 2187700300023 5.3000E+02 2.6000E+01 1.1200E+00 1.2000E-01 2187700300024 5.9000E+02 2.7000E+01 1.4800E+00 1.6000E-01 2187700300025 6.2500E+02 2.4000E+01 3.1100E+00 6.4000E-01 2187700300026 7.5000E+02 2.3000E+01 2.2600E+00 2.8000E-01 2187700300027 7.7500E+02 2.7000E+01 1.3900E+00 2.4000E-01 2187700300028 7.8000E+02 3.6000E+01 9.8000E-01 3.0000E-02 2187700300029 8.2000E+02 3.6000E+01 1.4700E+00 1.1000E-01 2187700300030 9.2500E+02 2.0000E+01 1.8400E+00 5.0000E-02 2187700300031 9.5000E+02 2.2000E+01 2.1700E+00 8.0000E-02 2187700300032 9.7500E+02 2.5000E+01 1.7600E+00 1.5000E-01 2187700300033 1.0000E+03 1.5000E+01 2.0100E+00 9.0000E-02 2187700300034 1.0500E+03 1.4000E+01 2.0300E+00 9.0000E-02 2187700300035 1.0750E+03 2.5000E+01 1.8300E+00 1.3000E-01 2187700300036 1.1000E+03 2.1000E+01 1.8700E+00 8.0000E-02 2187700300037 1.1250E+03 2.8000E+01 2.1500E+00 1.2000E-01 2187700300038 1.1500E+03 2.2000E+01 2.0700E+00 1.2000E-01 2187700300039 1.2000E+03 2.5000E+01 1.5000E+00 7.0000E-02 2187700300040 ENDDATA 24 0 2187700300041 ENDSUBENT 40 0 2187700399999 SUBENT 21877004 20110626 22262187700400001 BIB 3 13 2187700400002 REACTION (90-TH-228(N,F),,SIG) 2187700400003 ERR-ANALYS (ERR-S) error derived from the weighted deviations 2187700400004 from the weighted mean value of 5 runs. 2187700400005 (ERR-1) Error in solid angle subtended by the 2187700400006 Th-228 foil at the n-source. 2187700400007 (ERR-2) error in the long counter calibration and 2187700400008 the correction factor for neutron scattering 2187700400009 and the low-energy neutron group, 4.5% 2187700400010 (ERR-3) error in the Th-228 mass determination. 2187700400011 (ERR-T) .The total error in the tabulated cross 2187700400012 sections would be a combination of the listed errors. 2187700400013 HISTORY (20110304C) SD: Cross-section that measured several 2187700400014 times and used for normalization for others. 2187700400015 ENDBIB 13 0 2187700400016 COMMON 4 3 2187700400017 ERR-S ERR-1 ERR-2 ERR-3 2187700400018 PER-CENT PER-CENT PER-CENT PER-CENT 2187700400019 6.0000E-01 7.1000E+00 4.5000E+00 2.0000E+00 2187700400020 ENDCOMMON 3 0 2187700400021 DATA 3 1 2187700400022 EN DATA ERR-T 2187700400023 KEV MB MB 2187700400024 1.6350E+03 3.7000E+02 3.2000E+01 2187700400025 ENDDATA 3 0 2187700400026 ENDSUBENT 25 0 2187700499999 ENDENTRY 4 0 2187799999999