ENTRY 22918 20080606 21992291800000001 SUBENT 22918001 20080606 21992291800100001 BIB 17 54 2291800100002 TITLE .Measurement of the Po-210 production induced by 2291800100003 thermal neutron capture on Bi-209. 2291800100004 AUTHOR (A.Letourneau, G.Fioni, F.Marie, D.Ridikas, P.Mutti) 2291800100005 INSTITUTE (2FR SAC) 2291800100006 (2FR ILL) 2291800100007 REFERENCE (J,ANE,33,377,2006) Main reference 2291800100008 FACILITY (REAC,2FR ILL) Institute Laue-Langevin high-flux 2291800100009 heavy-water reactor 2291800100010 INC-SOURCE (REAC) T-4 position outside the reactor vessel at 2291800100011 aprx. 1.3 m from the fuel elements 2291800100012 INC-SPECT .In good approximation Maxwellian neutron spectrum at 2291800100013 the temperature 20 degree Celsius. For neutron flux 2291800100014 determination SIGMA(Co-60(n,gamma)) was adopted as 2291800100015 32.96 =- 0.06 barn (F.Marie et al., NIM/A,2006 - in 2291800100016 press), neutron fluxes are (2.32+-0/06)E+13 and 2291800100017 (2.34+-0.06)E+13 neutrons/cm2/sec for 3 and 7 days 2291800100018 irradiations 2291800100019 MONITOR ((MONIT)27-CO-59(N,G)27-CO-60,,SIG) The thermal neutron2291800100020 flux was monitored by the standard reaction. 2291800100021 DECAY-MON (27-CO-60,,DG,1173.24,, 2291800100022 DG,1332.50) 2291800100023 MONIT-REF .Vonach et al., K.I.Zvonarev, IRDF2002, 2002. 2291800100024 www.nndc.bnl.gov/nndcscr/libraries/irdf 2291800100025 ANALYSIS .Bi-210-G production identified with the production of 2291800100026 Po-210 2291800100027 COMMENT *By authors*.The cross section for the Po-210 2291800100028 production in the irradiation of a solid Bi-209 target 2291800100029 in a pure thermal neutron flux has been measured by 2291800100030 two distinct and direct experimental methods. The two 2291800100031 methods give comparable results compatible with the 2291800100032 older measurements, showing that experimental bias are 2291800100033 small and in particular the evaporation of Po-210 from 2291800100034 target. The new value measured in this work is by 25% 2291800100035 smaller than the used data-library values for the Po- 2291800100036 production. 2291800100037 DETECTOR (HPGE) In both experiments, the two 1173.24 and 1332.502291800100038 keV gamma-rays accompanying the decay Co-60 nucleus 2291800100039 were collected with high purity Ge-detectors. 2291800100040 METHOD (ACTIV) 2291800100041 (STTA) 2291800100042 ERR-ANALYS (DATA-ERR) The sources of errors associated with the 2291800100043 activation method. The main terms are the 2291800100044 error on the cross-section of the monitor and the 2291800100045 errors associated with the determination of the 2291800100046 activities, errors on the number of atoms in the 2291800100047 samples and finally, the errors on the half-lives, 2291800100048 the irradiation and cooling times. The latter errors 2291800100049 are negligible in comparison to the previous ones. 2291800100050 (ERR-1).The main error on the flux determination were 2291800100051 due to the errors on the mass fraction of Co-59 in the2291800100052 Al-foil-2% and the measured activities 2%. 2291800100053 STATUS (COREL,31552001) 2291800100054 HISTORY (20060302C) S.M. 2291800100055 (20080606U) Author name corrected - SM/HH 2291800100056 ENDBIB 54 0 2291800100057 COMMON 4 3 2291800100058 EN-DUMMY ERR-1 MONIT MONIT-ERR 2291800100059 EV PER-CENT MB MB 2291800100060 2.53E-02 2. 37.18 0.06 2291800100061 ENDCOMMON 3 0 2291800100062 ENDSUBENT 61 0 2291800199999 SUBENT 22918002 20060303 21762291800200001 BIB 7 22 2291800200002 REACTION (83-BI-209(N,G)83-BI-210-G,,SIG,,MXW) 2291800200003 DECAY-DATA (83-BI-210-G,5.013D,B-) Forming Po-210 2291800200004 (84-PO-210,138.376D,A,5304.38,0.9999878) Forming 2291800200005 Pb-206 in ground state 2291800200006 DETECTOR (GE-IN) A 300-micron thick passivated silicon detector.2291800200007 The energy resolution of the detector is 15 keV at 2291800200008 5486 keV gamma energy 2291800200009 SAMPLE .A very thin Bi-209 target of 1.1 micron in thickness 2291800200010 obtained by the evaporation onf 1 milligram of pure 2291800200011 Bi-209, isotopic purity 99.99%, with an uniformity of 2291800200012 2%, on a thick 0.125-mm Ni-backing were used. A nickel2291800200013 ring with 0.125-mm thick and 8-mm in diameter was 2291800200014 stacked on the deposit in order to collimate the 2291800200015 alpha emission from the target and thus to define an 2291800200016 exact emission surface and volume. 2291800200017 CORRECTION .A correction factor of 10+-10% was applied for the 2291800200018 measured activities and corrected for the particle 2291800200019 loss with a point-like emission solid angle fraction 2291800200020 was given. 2291800202291800200021 COMMENT *By authors*. The results, with the above adjustments, 2291800200022 given an activity of 5179+-518 Bq. 2291800200023 STATUS .Text of main reference, page 382 2291800200024 ENDBIB 22 0 2291800200025 NOCOMMON 0 0 2291800200026 DATA 2 1 2291800200027 DATA DATA-ERR 2291800200028 MB MB 2291800200029 16.08 1.8 2291800200030 ENDDATA 3 0 2291800200031 ENDSUBENT 30 0 2291800299999 SUBENT 22918003 20060303 21762291800300001 BIB 7 23 2291800300002 REACTION (83-BI-209(N,G)83-BI-210-G,,SIG,,MXW) 2291800300003 DECAY-DATA (83-BI-210-G,5.013D,B-) Forming Po-210 2291800300004 (84-PO-210,138.376D,A,4516.58,0.0000122) Forming 2291800300005 Pb-206 in excited state 803.1 keV 2291800300006 METHOD (GSPEC) 2291800300007 DETECTOR (GE-IN) The 803.1 keV gamma-ray has been collected with2291800300008 a Ge-detector which has an intrinsic efficiency of 10% 2291800300009 for the 1173-KeV gamma-ray and an energy resolution of 2291800300010 2.5-KeV. The total efficiency of the detector has 2291800300011 been calibrated with Eu-152 and Co-60 standard point- 2291800300012 like sources placed in front of the Ge-detector at 2291800300013 approximately 3-cm from the Ge-crystal. 2291800300014 SAMPLE .A thick 146-mg wire of pure Bi-209 was enclosed in 2291800300015 a 3 mm in diameter sealed quartz-capillary in order 2291800300016 to avoid any mass loss of Po. The dimension of the 2291800300017 wire was 1 mm diameter and 10 mm long which makes the 2291800300018 gamma self-shielding negligible. The monitor sample 2291800300019 is AL-0.1%Co alloy (7.58+-0.01) milligram encapsulated2291800300020 in an identical capillary 2291800300021 COMMENT *By authors*. The result of the adjustments with this 2291800300022 function on the Po-210 data given an activity of 2291800300023 2140+-42 Kbq. 2291800300024 STATUS .Text of main reference, page 382 2291800300025 ENDBIB 23 0 2291800300026 NOCOMMON 0 0 2291800300027 DATA 2 1 2291800300028 DATA DATA-ERR 2291800300029 MB MB 2291800300030 18.4 0.9 2291800300031 ENDDATA 3 0 2291800300032 ENDSUBENT 31 0 2291800399999 SUBENT 22918004 20060303 21762291800400001 BIB 3 7 2291800400002 REACTION (83-BI-209(N,G)83-BI-210-G,,SIG,,MXW,DERIV) Recom- 2291800400003 mended value from both measurements 2291800400004 REL-REF (D,,I.SEREN+,J,PR,72,888,1947) 2291800400005 (D,,F.C.W.COLMER,J,PPS/A,63,1175,1950) 2291800400006 STATUS .Text of main reference, page 382 2291800400007 (DEP,22918002) 2291800400008 (DEP,22918003) 2291800400009 ENDBIB 7 0 2291800400010 NOCOMMON 0 0 2291800400011 DATA 2 1 2291800400012 DATA DATA-ERR 2291800400013 MB MB 2291800400014 17.9 0.8 2291800400015 ENDDATA 3 0 2291800400016 ENDSUBENT 15 0 2291800499999 ENDENTRY 4 0 2291899999999