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US Nuclear Data Program Meeting 1999 Held at Brookhaven National Laboratory April 26-29, 1999 |
To NNDC
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US Nuclear Data Program Meeting 1999 Held at Brookhaven National Laboratory April 26-29, 1999 |
To NNDC
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Abstract: This document compiles informal progress reports from
laboratories participating in the US Nuclear Data Program, and focuses on
nuclear reaction data work from April 1998 - April 1999.
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Abstract: Analysis of neutron activation cross sections from 16-20 MeV that were measured
in 1996 at the IRMM Van de Graaff facility in Geel, Belgium, has been completed
and a paper has been submitted for publication. A new set of measurements was
performed at the IRMM facility during May-June 1998 as part of an on-going
collaboration between Argonne, IRMM, and JAERI. Experimental and evaluated data
for neutron-induced hydrogen production reactions on vanadium have been compiled
and critically examined. This investigation led to a recommendation that
ENDF/B-VI evaluations for the (n,np+pn) and (n,t) processes be revised. These
revisions lead to a reduction by a factor of about 3 in hydrogen production
from vanadium at 14 MeV neutron energy. The compilation of
(p,
) and
(p,
) cross-section and resonance-parameter data for several isotopes of
sulfur is now in progress. This information will be published in an Argonne
report and posted on the World Wide Web to guide the evaluation of cross
sections relevant to stellar hydrogen burning. They are used in the
nucleo-synthesis network calculations for astrophysics.
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Abstract: This report reviews the activities of the National Nuclear
Data Center (NNDC) for the period April 1998 to March 1999, for the second
meeting of the U.S. Nuclear Data Program (USNDP), April 26-29, 1999. The
activities of the Center in this period included the comlibation and
evaluation of nuclear structure and decay data; compilation of nuclear
reaction data; maintenance of bibliographic databases in the areas of
nuclear physics; support of various national and international groups
concerned with the collection, evaluation, and dissemination of nuclear
data; dissemination of the data resident in the NNDC's databases via
the Internet and other means; and acting as the U.S. repository of low-
and medium-energy nuclear data.
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Abstract: Within our mass range of responsibility, the evaluation
for A=154 has been added to ENSDF and those for A=162 and 163 (the latter
done by B. Singh) have been submitted, which accounts for the A-chains on
the August 1998 priority list. Of the 16 priority nuclides in our mass
region on that list, 10 have been submitted in these A-chain evaluations
and 161Dy and 161Yb are being evaluated. In support
of ENSDF, we have coordinated the work of the Working Group on Nuclear
Structure and Decay Data for the US Nuclear Data Program and the
international Decay Data Evaluation Project. We are also participating in
an IAEA Coordinated Research Project on decay data evaluation and
preparing a paper on gamma-ray energies for detector calibration.
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Abstract: The Isotopes Project is responsible for the evaluation of 41
mass chains with mass number A between 59 and 227. Since the April '98
USNDP Meeting, the Isotopes Project has submitted revised evaluations
for 3 of these chains (which include 8 priority nuclides) and also for
the A>265 chains (8 chains, 11 nuclides). Complete evaluations for 18
individual nuclides have also been submitted to NNDC and all but one of
those have already been incorporated in ENSDF. The Isotopes Project
participates in two international collaborations for data evaluation:
the Decay Data Evaluation Project (DDEP), which evaluates data for
nuclides of interest in applied research (for which 4 nuclides of
astrophysical interest were prepared this year), and a US-Hungary
collaboration for the evaluation of data from
(n,) reactions (for which the preparation of 43 data sets for A<50 is
nearing completion). A number of high-spin data sets, compiled by the Isotopes
Project in prior years, have now been edited at McMaster University and make a
significant contribution to the new XUNDL database. Reviews of
evaluations for 2 mass chains and 9 DDEP nuclide decay data sets have
been provided by the Isotopes Project. ENSDF coding of non-US
evaluations (4 DDEP nuclide decays and Endt's A=21-39 update) has
commenced.
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Abstract: NIST's primary evaluation effort is the new international
evaluation of the neutron cross section standards. Much of the effort so
far has been focused on investigating the cross section database. The
investigation has involved finding the experimental data through papers,
reports, etc and examining them so the data can be prepared for use in the
evaluation. Efforts are being made to increase the manpower available for
work on this evaluation. NIST has been involved in a number of experiments.
Measurements have been completed of the angular distribution of neutrons
scattered by hydrogen at 10 MeV neutron energy by a Ohio
University-NIST-LANL collaboration. The data are under analysis and new
measurements at 14 MeV are being planned. Measurements have been made of
the coherent scattering lengths of 208Pb and silicon. A calorimeter has
been built for very accurate determinations of neutron fluence. This
calorimeter will be used to improve the accuracy of the emission rate of the
artifact standard neutron source, NBS-1. This capability can be used to
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Abstract: The status of the Nuclear Data Evaluation work done
during April 1998 to April 1999 is presented together with
other activities and work in progress.
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Abstract: A short outline of the nuclear structure and decay data
activities of the NIST Radioactivity Group is given.
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Abstract: This report provides a brief overview of the recent activities of the
Triangle Universities Nuclear Laboratory's Nuclear Data Evaluation Group
(TUNL-NDEP). Information on the status of mass chain evaluations, ENSDF
activity and the WWW site are provided. Primary accomplishments in the
past year include the release of a preliminary A=6 evaluation and ENSDF
revisions for 10 mass chains in the A=2-20 region.
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Abstract: As a result of discussions at meetings of the High-spin
task force of the US DOE Nuclear Data Program, a new database has been
implemented which contains unevaluated nuclear structure data. Each data
set in XUNDL contains the results of a single publication or a few closely
related publications. The data format for XUNDL data sets is identical to
that for ENSDF. Data sets indexed by mass number, nuclide and reference
(NSR) keynumbers are currently accessible from BNL (via WWW or
TELNET). As of March 31, the database contained 153 data sets for 134
nuclides (from 43Ca to 254No) spread over 83 mass
chains.
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Abstract: The current status of the ENSDF Analysis and Utility Codes
is summarized and future plans discussed.
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Abstract: Neutron induced prompt gamma activation analysis (PGAA) is a
non-destructive radio-analytical method capable of identifying nearly the
entire periodic table. Availability of high-quality thermal and cold
neutron beams has facilitated the development of PGAA. This method has
been applied to materials science, chemistry, geology, mining, archaeology,
environment, food analysis, medicine and other areas. Inaccurate and
incomplete data available for PGAA are a significant handicap to its
development. These deficiencies were recognized during the meeting on the
Coordination of the Nuclear Structure and Decay Data Evaluators' Network
held at Budapest in 1996 and have led to the IAEA CRP, starting in 1999
for three years, that is described here.
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Abstract: In order to help guide future development of the Nuclear Science References database, a short user survey will be distributed at the meeting. A survey of the wider user community is planned for sometime in the next few months.
Abstract: Proposals for changes in the presentation in the
Nuclear Data Sheets and for additions or changes to the ENSDF
checking codes are presented.
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