ENTRY 20192 20230202 231420192 0 1 SUBENT 20192001 20230202 231420192 1 1 BIB 13 66 20192 1 2 TITLE A precise determination of the thermal neutron 20192 1 3 absorption cross-section of B-10 and natural boron 20192 1 4 by time-of-flight 20192 1 5 AUTHOR (A.Prosdocimi, A.J.Deruytter, G.Debus, P.J.Debievre, 20192 1 6 J.Spaepen, K.Lauer, H.Moret) 20192 1 7 INSTITUTE (2BLGMOL) A.J.Deruytter 20192 1 8 (2ZZZGEL) 20192 1 9 REFERENCE (J,JNE/AB,17,83,1963) Only graph given. 20192 1 10 (J,JNE,21,373(1),1967) Revised values for the boron 20192 1 11 isotopic composition giving revised values for the 20192 1 12 2200 m/sec (n,alpha) cross section. 20192 1 13 Authors of JNE,21,373: G.H.Debus, P.J.De Bievre. 20192 1 14 (J,JNE/AB,17,349(1),1963) Material analysis. 20192 1 15 Authors of JNE/AB,17,349: P.J.Debievre,G.H.Debus, 20192 1 16 J.Spaepen 20192 1 17 (R,EUR-12E,1962) Detailed description of experiment 20192 1 18 and tables of the total cross sections for B2O3. 20192 1 19 Authors of R,EUR-12E : A.J.Deruytter,G.Debus,K.Lauer, 20192 1 20 H.Moret,A.Prosdocimi 20192 1 21 (P,EANDC(E)-23,2,1962) Progress report. 20192 1 22 FACILITY (REAC,2BLGMOL) BR1-reactor in MOL, thermal column, 20192 1 23 (CHOPS,2BLGMOL) 20192 1 24 INC-SOURCE (THCOL) Thermal column, and slow chopper. 20192 1 25 Neutron energy resolution 42 to 56 microsec/m. 20192 1 26 SAMPLE Two samples of deuterated boric acid used, supplied 20192 1 27 by ornl. The boron content of the samples was determ. 20192 1 28 By titration against sodium hydroxide of calibrated 20192 1 29 strength,and the isotopic composition of the boron was20192 1 30 determined by mass spectrometry. A small mass 20192 1 31 discrimination was suspected in the 1962 measurements,20192 1 32 revised isotopic compositions were published in 1967. 20192 1 33 The measuring cells were made of fused quartz, diam. 20192 1 34 of 52 mm and length of 20 mm. 20192 1 35 METHOD (TOF,TRN) Transmission measurement of deuterated boric 20192 1 36 acid solution. The neutron beam was monitored with a 20192 1 37 parallel plate fission flow counter with a low 20192 1 38 efficiency U-235 layer. 20192 1 39 The length of the flight path was 194.70+-0.02 cm. 20192 1 40 DETECTOR (BF3) 20192 1 41 STATUS (TABLE) Data for the (n,a) cross section is from a 20192 1 42 private communication, and are derived from values 20192 1 43 given in the tables for the B2O3 total cross section 20192 1 44 in table IV of EUR-12E. 20192 1 45 CORRECTION The results are corrected for multiple scattering in 20192 1 46 the samples using a simplified analytical model. The 20192 1 47 corrections are small. 20192 1 48 ERR-ANALYS (ERR-S) Statistical error. This is by far the largest 20192 1 49 contribution to the total uncertainty. 20192 1 50 (ERR-1) The uncertainty in the boron-10 isotopic 20192 1 51 composition is 0.15% from the natural boron 20192 1 52 measurements. 20192 1 53 (ERR-2) The uncertainty in the boron-10 isotopic 20192 1 54 composition is 0.006% in the enriched 20192 1 55 boron measurements. 20192 1 56 (ERR-3,,1.) Systematic uncertainty from the multiple 20192 1 57 scattering correction is less than 0.1%. 20192 1 58 HISTORY (19721005T) 20192 1 59 (19810212A) More information added,and subentries 004, 20192 1 60 005 added. 20192 1 61 (20060807A) Date and reference are corrected. 20192 1 62 BIB information of sub.004 was added. 20192 1 63 (20070728A) S.M. Final serious corrections done 20192 1 64 (20070728U) Last checking has been done. 20192 1 65 (20230130U) SD: ERR-ANALYS updated. Ref corrected. 20192 1 66 (JNE/AB,17,349,1963: 349 -> 349(1)). Small 20192 1 67 corrections in all Subents. 20192 1 68 ENDBIB 66 0 20192 1 69 COMMON 2 3 20192 1 70 ERR-1 ERR-2 20192 1 71 PER-CENT PER-CENT 20192 1 72 0.15 0.006 20192 1 73 ENDCOMMON 3 0 20192 1 74 ENDSUBENT 73 0 20192 199999 SUBENT 20192002 20230202 231420192 2 1 BIB 5 17 20192 2 2 REACTION (5-B-0(N,A),,SIG) 20192 2 3 SAMPLE Natural boron, the isotopic composition of B-10 20192 2 4 was measured in 1962 as 19.81+-0.02%, revised to 20192 2 5 a value of 19.838+-0.030 in 1967 (JNE,21,373). 20192 2 6 ANALYSIS The total cross section of B2O3 was measured in two 20192 2 7 separate runs, K-from 0.006 to 0.027 eV, L-from 0.013 20192 2 8 to 0.082 eV. The (n,alpha) cross section of this boron20192 2 9 is derived from these measurements assuming a value 20192 2 10 for oxygen total cross section of 4.24+-0.02 b, and 20192 2 11 for the B-10 and B-11 scattering cross sections 4.0 20192 2 12 and 4.4 b. The values correspond to those derived from20192 2 13 table IV using the formula ... 20192 2 14 Sigma (n,alpha) = 1/2( (B2O3)total - 21b) 20192 2 15 STATUS (TABLE) Private communication, 1963. 20192 2 16 HISTORY (19810212A) Details of sample and analysis added. 20192 2 17 (20070728A) Err-1 moved to SAN 001 as ERR-SYS 20192 2 18 (20230130U) SD: BIB updated. 20192 2 19 ENDBIB 17 0 20192 2 20 NOCOMMON 0 0 20192 2 21 DATA 3 50 20192 2 22 EN DATA ERR-S 20192 2 23 EV B B 20192 2 24 6.0100E-03 1.4990E+03 3.0000E+01 20192 2 25 6.2800E-03 1.4090E+03 2.6000E+01 20192 2 26 6.5800E-03 1.5370E+03 2.5000E+01 20192 2 27 6.8900E-03 1.4150E+03 2.1000E+01 20192 2 28 7.2300E-03 1.4800E+03 2.0000E+01 20192 2 29 7.5900E-03 1.3810E+03 1.6000E+01 20192 2 30 7.9800E-03 1.3120E+03 1.6000E+01 20192 2 31 8.4000E-03 1.2720E+03 1.4000E+01 20192 2 32 8.8600E-03 1.3020E+03 1.4000E+01 20192 2 33 9.3500E-03 1.2560E+03 1.3000E+01 20192 2 34 9.8900E-03 1.2530E+03 1.2000E+01 20192 2 35 1.0500E-02 1.2280E+03 1.2000E+01 20192 2 36 1.1100E-02 1.1050E+03 9.0000E+00 20192 2 37 1.1800E-02 1.1100E+03 8.0000E+00 20192 2 38 1.2600E-02 1.0710E+03 7.0000E+00 20192 2 39 1.3400E-02 1.0140E+03 6.0000E+00 20192 2 40 1.3500E-02 1.0220E+03 7.0000E+00 20192 2 41 1.4200E-02 1.0200E+03 7.0000E+00 20192 2 42 1.4300E-02 1.0310E+03 6.0000E+00 20192 2 43 1.4900E-02 9.9320E+02 6.7000E+00 20192 2 44 1.5400E-02 1.0080E+03 6.0000E+00 20192 2 45 1.5700E-02 9.9030E+02 6.9000E+00 20192 2 46 1.6500E-02 9.3700E+02 5.8000E+00 20192 2 47 1.6600E-02 9.2920E+02 6.3000E+00 20192 2 48 1.7600E-02 8.9260E+02 5.5000E+00 20192 2 49 1.7800E-02 8.9630E+02 5.1000E+00 20192 2 50 1.8600E-02 8.8560E+02 5.2000E+00 20192 2 51 1.9200E-02 8.7420E+02 4.5000E+00 20192 2 52 1.9700E-02 8.6900E+02 4.6000E+00 20192 2 53 2.0800E-02 8.5040E+02 3.9000E+00 20192 2 54 2.1000E-02 8.5520E+02 4.1000E+00 20192 2 55 2.2300E-02 8.1240E+02 3.7000E+00 20192 2 56 2.2700E-02 8.0570E+02 3.4000E+00 20192 2 57 2.3800E-02 8.0070E+02 3.4000E+00 20192 2 58 2.4700E-02 7.6670E+02 3.2000E+00 20192 2 59 2.5500E-02 7.4290E+02 3.3000E+00 20192 2 60 2.7100E-02 7.3860E+02 3.0000E+00 20192 2 61 2.7300E-02 7.3440E+02 3.1000E+00 20192 2 62 2.9400E-02 7.1530E+02 2.9000E+00 20192 2 63 3.1600E-02 6.7380E+02 2.7000E+00 20192 2 64 3.4200E-02 6.6770E+02 2.7000E+00 20192 2 65 3.7000E-02 6.2810E+02 2.6000E+00 20192 2 66 4.0300E-02 6.1080E+02 2.5000E+00 20192 2 67 4.3900E-02 5.6730E+02 2.4000E+00 20192 2 68 4.8100E-02 5.5150E+02 2.3000E+00 20192 2 69 5.3000E-02 5.2240E+02 2.2000E+00 20192 2 70 5.8600E-02 4.9160E+02 2.2000E+00 20192 2 71 6.5100E-02 4.6890E+02 2.1000E+00 20192 2 72 7.2800E-02 4.4610E+02 2.1000E+00 20192 2 73 8.2000E-02 4.1960E+02 2.2000E+00 20192 2 74 ENDDATA 52 0 20192 2 75 ENDSUBENT 74 0 20192 299999 SUBENT 20192003 20230202 231420192 3 1 BIB 5 20 20192 3 2 REACTION (5-B-10(N,A)3-LI-7,,SIG) 20192 3 3 SAMPLE Enriched boron with an isotopic composition in B-10 20192 3 4 measured in 1962 as 96.515+-0.013%, and revised 20192 3 5 in 1967 to a value of 96.525+-0.006%. 20192 3 6 ANALYSIS These data are derived from measurements of the total 20192 3 7 cross section of enriched B2O3, in two separate runs, 20192 3 8 K from 0.006 to 0.027 eV and l from 0.013 to 0.082 eV 20192 3 9 The total cross section for B-10 is derived assuming 20192 3 10 a total cross section for oxygen of 4.24+-0.02 b 20192 3 11 and scattering cross sections for B-10 and B-11 of 20192 3 12 4.0 and 4.4 b, respectively. The data are derived from20192 3 13 the total cross section given in table IV of EUR-12E 20192 3 14 using the formula ... 20192 3 15 Sigma (n,alpha) = 1/2( (B2O3)total - 21b ) * 1/0.96520192 3 16 the final term is the correction for the isotopic 20192 3 17 composition of the sample. 20192 3 18 STATUS (TABLE) Private communication, 1963. 20192 3 19 HISTORY (19810212A) Details of sample and analysis given. 20192 3 20 (20070728A) ERR-1 moved to SAN 001 as ERR-SYS 20192 3 21 (20230130U) SD: BIB updated. 20192 3 22 ENDBIB 20 0 20192 3 23 NOCOMMON 0 0 20192 3 24 DATA 3 50 20192 3 25 EN DATA ERR-S 20192 3 26 EV B B 20192 3 27 6.0100E-03 7.4720E+03 4.2900E+02 20192 3 28 6.2800E-03 6.9310E+03 3.7200E+02 20192 3 29 6.5800E-03 7.4420E+03 3.2300E+02 20192 3 30 6.8900E-03 7.3400E+03 3.0700E+02 20192 3 31 7.2300E-03 6.9840E+03 2.6300E+02 20192 3 32 7.5900E-03 6.6440E+03 2.3500E+02 20192 3 33 7.9800E-03 6.5000E+03 2.2300E+02 20192 3 34 8.4000E-03 6.1160E+03 1.9400E+02 20192 3 35 8.8600E-03 6.4700E+03 1.9100E+02 20192 3 36 9.3500E-03 6.3990E+03 1.7700E+02 20192 3 37 9.8900E-03 5.9640E+03 1.6400E+02 20192 3 38 1.0500E-02 5.6580E+03 1.5400E+02 20192 3 39 1.1100E-02 5.4230E+03 1.2300E+02 20192 3 40 1.1800E-02 5.3620E+03 1.0800E+02 20192 3 41 1.2600E-02 5.2040E+03 9.6000E+01 20192 3 42 1.3400E-02 5.2110E+03 8.6000E+01 20192 3 43 1.3500E-02 5.1150E+03 9.8000E+01 20192 3 44 1.4200E-02 5.1420E+03 9.7000E+01 20192 3 45 1.4300E-02 5.1440E+03 8.3000E+01 20192 3 46 1.4900E-02 5.0100E+03 9.6000E+01 20192 3 47 1.5400E-02 4.6370E+03 8.0000E+01 20192 3 48 1.5700E-02 4.8380E+03 9.7000E+01 20192 3 49 1.6500E-02 4.5210E+03 7.7000E+01 20192 3 50 1.6600E-02 4.6250E+03 8.8000E+01 20192 3 51 1.7600E-02 4.4660E+03 7.7000E+01 20192 3 52 1.7800E-02 4.3040E+03 6.6000E+01 20192 3 53 1.8600E-02 4.4920E+03 7.3000E+01 20192 3 54 1.9200E-02 4.2560E+03 5.9000E+01 20192 3 55 1.9700E-02 4.2680E+03 6.4000E+01 20192 3 56 2.0800E-02 4.0040E+03 5.1000E+01 20192 3 57 2.1000E-02 4.2550E+03 5.7000E+01 20192 3 58 2.2300E-02 4.0790E+03 5.1000E+01 20192 3 59 2.2700E-02 3.8960E+03 4.5000E+01 20192 3 60 2.3800E-02 4.0040E+03 4.8000E+01 20192 3 61 2.4700E-02 3.7110E+03 4.1000E+01 20192 3 62 2.5500E-02 3.8560E+03 4.6000E+01 20192 3 63 2.7100E-02 3.5970E+03 3.9000E+01 20192 3 64 2.7300E-02 3.7320E+03 4.3000E+01 20192 3 65 2.9400E-02 3.4910E+03 4.0000E+01 20192 3 66 3.1600E-02 3.4270E+03 3.8000E+01 20192 3 67 3.4200E-02 3.3400E+03 3.7000E+01 20192 3 68 3.7000E-02 3.2660E+03 3.6000E+01 20192 3 69 4.0300E-02 3.0760E+03 3.4000E+01 20192 3 70 4.3900E-02 2.9290E+03 3.3000E+01 20192 3 71 4.8100E-02 2.7850E+03 3.2000E+01 20192 3 72 5.3000E-02 2.6280E+03 3.1000E+01 20192 3 73 5.8600E-02 2.5410E+03 3.0000E+01 20192 3 74 6.5100E-02 2.3790E+03 2.9000E+01 20192 3 75 7.2800E-02 2.2870E+03 2.9000E+01 20192 3 76 8.2000E-02 2.1660E+03 2.8000E+01 20192 3 77 ENDDATA 52 0 20192 3 78 ENDSUBENT 77 0 20192 399999 SUBENT 20192004 20230202 231420192 4 1 BIB 7 22 20192 4 2 REACTION (5-B-10(N,A)3-LI-7,,SIG) 20192 4 3 ANALYSIS Derived from measurements of the total cross section 20192 4 4 of samples of B2O3. The contribution to the total 20192 4 5 cross section from reactions other than B-10(n,alpha) 20192 4 6 is assumed to be 21.0+-1.0 B. The plot of the 20192 4 7 B-10(n,alpha) cross section against 1/V is seen to be 20192 4 8 constant, from which the 2200 m/sec value is derived 20192 4 9 using the mean value and the B-10/(B-10+B-11) isotopic20192 4 10 ratio. The absorption cross section of B-11 (0.005 b) 20192 4 11 is neglected. 20192 4 12 EXP-YEAR (1962) 20192 4 13 CORRECTION Using the 1967 year isotopic compositions of 20192 4 14 (19.838+-0.030)% for the natural boron sample and 20192 4 15 (96.525+-0.006)% for the enriched sample the values 20192 4 16 given here are derived on the base of new (1967year) 20192 4 17 spectrometric results from exp.data of 1962year. 20192 4 18 FLAG (1.) Natural boron sample. 20192 4 19 (2.) Enriched boron sample. 20192 4 20 STATUS (TABLE) Table in J.Nucl.Ener.,21,373. 20192 4 21 HISTORY (19810212C) Subentry added. 20192 4 22 (20070728A) Err-sys moved to SAN 001 20192 4 23 (20230130U) SD: BIB updated. 20192 4 24 ENDBIB 22 0 20192 4 25 COMMON 1 3 20192 4 26 EN 20192 4 27 EV 20192 4 28 2.53E-02 20192 4 29 ENDCOMMON 3 0 20192 4 30 DATA 3 2 20192 4 31 DATA ERR-S FLAG 20192 4 32 B B NO-DIM 20192 4 33 3835. 11. 1. 20192 4 34 3836. 9. 2. 20192 4 35 ENDDATA 4 0 20192 4 36 ENDSUBENT 35 0 20192 499999 SUBENT 20192005 20230202 231420192 5 1 BIB 5 12 20192 5 2 REACTION (5-B-0(N,A),,SIG) 20192 5 3 SAMPLE Natural boron, isotopic composition of 19.838% B-10 20192 5 4 ANALYSIS This value is derived from the total cross section 20192 5 5 measurements on natural B2-O3 from which the (n,alpha)20192 5 6 cross section is seen to be accurately 1/V. 20192 5 7 The mean value of the ratio sigma(n,alpha)/flight time20192 5 8 is used to derive this reference value for the 20192 5 9 2200 m/sec cross section. 20192 5 10 STATUS (TABLE) Value given in J.Nucl.Ener.,21,373. 20192 5 11 HISTORY (19810212C) Subentry added. 20192 5 12 (20070728A) ERR-1 moved to SAN 001 as ERR-SYS 20192 5 13 (20230130U) SD: BIB updated. 20192 5 14 ENDBIB 12 0 20192 5 15 NOCOMMON 0 0 20192 5 16 DATA 3 1 20192 5 17 EN DATA ERR-S 20192 5 18 EV B B 20192 5 19 0.0253 760.8 1.9 20192 5 20 ENDDATA 3 0 20192 5 21 ENDSUBENT 20 0 20192 599999 ENDENTRY 5 0 2019299999999