Presentation on theme: "Evaluated Gamma-ray Activation File (EGAF) Richard B. Firestone Isotopes Project, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 IAEA NSDD Meeting,"— Presentation transcript:
Evaluated Gamma-ray Activation File (EGAF) Richard B. Firestone Isotopes Project, Lawrence Berkeley National Laboratory, Berkeley, CA IAEA NSDD Meeting, 4-8 April 2011, Vienna
EGAF Capture Gamma Ray Collaboration Isotopes Project (LBNL) - R.B. Firestone, A. Hurst, S. Basunia LLNL Nuclear Data Library – B. Sleaford, N. Summers Budapest Reactor – Zs. Revay, T. Belgya, L. Szentmiklosi NIF STARS/LiBeRACE Collaboration – L. Bernstein, D. Bleuel, J.A. Caggiano, D.H.G. Schneider, W. Stoeffl (LLNL) M. Wiedeking (iThemba Labs, South Africa) M. Krticka (Charles University, Prague) S. Siem, A. Goergen, M. Guttormsen, A.C. Larsen (U. Oslo) C. Beausang (University of Richmond) IAEA Nuclear Data Section –D. Abriola, R. Capote, M. Kellett, V. Zerkin
History of EGAF Before 1996 no reliable database was available. 1996: At CGS9 (Budapest) initial discussions begin on the development of a k 0 / database based on Budapest Reactor measurements – 2003: IAEA CRP on Development of a Database for Prompt Gamma- ray Neutron Activation Analysis. First evaluation of prompt k 0 / database. 2004: Publication of the Handbook of Prompt Gamma Activation Analysis (Kluwer Publishers). Budapest prompt data and spectra for all elements. 2006: Release of EGAF database IAEA - LBNL : IAEA Publication of the Database of Prompt Gamma Rays from Slow Neutron Capture for Elemental Analysis. Results of IAEA CRP – 2010: IAEA CRP on Reference Database for Neutron Activation Analysis. Intercomparison of literature, EGAF and IUPAC /k 0 / 0 data – present: Evaluation of EGAF 2 begins. 2008: LLNL/LBNL collaboration for an ENDF capture -ray library. 2009: LBNL Isotopes Project begins evaluation of Reaction Input Parameter Library (RIPL) data 2010: LBNL begins discussion of evaluation of activation data for the DDEP.
EGAF Database Content Prompt thermal (n, ) data Capture -ray energies E Capture -ray thermal cross sections PGAA k 0 factors Recommended I per 100 neutron captures Neutron separation energies S N Thermal neutron capure state widths RIPL nuclear structure data -Recommended J values from experiment and theory -New J values from statistical model calculations -Improved level -ray branching intensities Activation thermal (n, ) data Energies and tranistion probabilities E , P Normalization to -ray cross sections, NAA k 0 factors calculated from and P Total radiative cross sections Compilation of measured values (corrected for new standard data) New values derived from prompt (n, ) data and statistical model calculations Recommended values from all data
Neutron beam measurements - Budapest Reactor and neutron guide hall. The PGAA (capture -ray) station is located 30 m from the reactor wall where backgrounds are low. HPGe efficiency precision 6 MeV. Compton suppression ≈5 (1332 keV) to ≈40 (7000 keV) Neutron flux is 1.2 10 8 n/cm 2
Neutron beam measurements - Munich New experiments planned at Munich for 2011 ( 2 H, 3 He, 90 Zr) 7.3 10 9 n/cm 2 at target position (14 mm 38 mm beam) 2 n/cm 2 at He gas-flushed elliptical guide (4 mm 10 mm beam)
Cross section standardization methods 1. Stoichiometric compounds containing elements with well-known cross sections: H, N, Cl, S, Na, Ti, Au KCl, (CH 2 ) n, Pb(NO 3 ) 2, Tl 2 SO 4 2.Homogenous mixtures Aqueous (H 2 O) or acid (20% HCl) solutions Mixed powders (TiO 2 ) 3.Activation products with well-known P 19 F, 28 Al, 100 Tc, 235 U Measurements have been completed on all elemental targets Z=1-83, 92 except for He and Pm and on the radioactive targets 99 Tc, and 129 I
The k 0 PGAA/NAA Method Relative -ray intensities measured in PGAA/NAA from different elements can be converted to relative masses using the -ray k 0 factors.
EGAF Database Sources IAEA Database of Prompt Gamma Rays from Slow Neutron Capture for Elemental Analysis PGAA-IAEA Database Viewer
EGAF Data Analysis Hypermet peak analysis Budapest Reactor Capture -ray spectrum 1.Analyzed spectrum using Hypermet 2.Place -rays in ENSDF format (n, ) dataset 3.Normalize data to Budapest cross section 4.Check intensity balance for problems 5.Determine , S N, …. 6.Analyze activation data from ENSDF, DDEP
Total radiative cross sections ( (in) (out) For complete low-Z level schemes are determined from EGAF data Author (Year) 0 (mb) Prestwich (1981)3.50±0.16 Jurney (1982)3.53±0.07 Nichols (1960)3.57±0.03 Sagot (1963)3.72±0.15 Jurney (1963)3.8±0.4 Starr (1962)3.83±0.06 Hennig (1967)3.85±0.15 Matsue (2004)3.81±0.11 EGAF (2007)3.85±0.06 Mughabghab Atlas3.53±0.07 Comparison of 12 C values
Determining for complex level schemes Below E crit all nuclear structure is known (RIPL) All primary -ray to levels below E crit are measured (Budapest) The rest of the levels and -rays can be calculated with DICEBOX = (GS) obs + (GS) stat Population/Depopulation plot
IUPAC NAA k0 Database Based on measurements of Frans De Corte and Andras Simonits, Atomic Data and Nuclear Data Tables 85 (2003) 47–67. Adopted by International Union of Pure and Applied Chemistry, Pure Appl. Chem., Vol. 76, No. 10, pp. 1921–1925, Contains recommended “experimental” k 0 values that have not been “evaluated” by comparison with other cross section measurements. A k 0 committee led by Zsolt Revay has been formed to look into updating the database Tradition dictates a “pure” experimental approach. The evaluation community favors a data comparison. “Reference Database for NAA” This led to the IAEA CRP “Reference Database for NAA” An IAEA consultants meeting next week will discuss how to proceed. An IAEA consultants meeting next week will discuss how to proceed. Any one interested can join an informal discuss this week. Any one interested can join an informal discuss this week.
3rd IAEA Research Coordination Meeting on “Reference Database for NAA” 24 Na g (NAA) 542(3) mb 0 (PGAA) 540(4) mb (Atlas) 517(4) mb 24 Na m (NAA) 478(4) mb (Atlas) 400(3) mb 36 S k 0 (NAA) 3.05(10) k 0 (IUPAC) 1.96(4) K 41 K (PGAA) 2.21(3) b (Atlas) 2.1(2) b 40 K (PGAA) 90(3) b (Atlas) 30(8) b 42 K (PGAA) 1.522(22) b (Atlas) 1.46(3) b 31 Si(E =1266 keV) P (ENSDF) (4) P (PGAA) (12) 45 Sc m (NAA) 7.77(21) b (Atlas) 9.9(11) b 70 Zn (NAA) 83(5) mb (Atlas) 22 mb 127 I (IUPAC) 5.48(12) b (Atlas) 6.15(6) or for E =443 keV P (ENSDF) (8) P (Atlas) 0.112(3) 186 W (NAA) 34.8(2) b (Atlas) 38.1(5) b Comparison of selected IUPAC(k 0 ), Atlas( ), and EGAF( ) PGAA/NAA data 114m In(t 1/2 =49.51 d) ENSDF %IT 96.75(24) %EC+ 3.25(24) EGAF-NAA %IT 95.72(7) %EC+ (7) ( 155 Gd(n, ) 156 Gd) Atlas60,900(500) EGAF66,200(4,100) ( 157 Gd(n, ) 158 Gd) Atlas254000(815) EGAF216000(5000)
Proposed EGAF Publication in NDS EGAF Publication Considerations 1. First publish data in refereed journals 2. Then publish detailed EGAF evaluation in NDS a.Adopted EGAF dataset – E , , k 0, , S n, RIPL levels b.Supporting datasets – E , I g c.Activation decay datasets – E , P , , k 0 3.Finally provide updated EGAF database to IAEA Why Nuclear Data Sheets? 1.Existing NDS production procedures are satisfactory 2.Most suitable journal for nuclear data publication 3.Detailed information on EGAF evaluation not in journal
General comments – summary Summary of values from the literature (CSISRS) and this evaluation
RIPL Adopted Level Data Cross section balance through the (n, ) level scheme. Justification of RIPL J assignments.
Adopted , k 0 Data Both -ray cross sections and k 0 values
Level scheme drawing Possibly too complex?
Supporting Budapest Dataset Primary data source. Other important datasets from the literature will be included.
Adopted I per 100 neutron captures table I per 100 neutron captures normalized to
Activation decay data P on table, conversion factor to on drawing
Adopted RIPL Nuclear Structure File
LLNL – ENDF/ENSDF Database Project LLNL has begun a 5-year USDOE funded project to develop a General Nuclear Database that will include ENDF, ENSDF, and other databases using Extensible Markup Language (XML) to serve these data to various applications. ApplicationsENDFGND ENSDF RIPL Other Data AME Masses XUNDL, EGAF Atomic data ENSDF input physics checking Automatic AME updating Replacement of ENSDF “card image” structure with modern XML capabilities. Future “home” of RIPL and EGAF
Future Considerations Recommendations 1.Publish new elemental evaluations in Nuclear Data Sheets after prompt -ray journal publication 2.Publish activation data in DDEP Table of Radionuclides 3.ENSDF proposals Provide -ray cross section normalization to barns Include on primary capture -ray and calculate reduced transition probabilities. 4.IUPAC NAA k 0 database Provide recommended E , t 1/2 data from ENSDF/DDEP Compare recommended k 0 values with EGAF evaluation Supplement k 0 database with complete -ray list.