Coordinated Research Project on Photonuclear Data and Photon Strength Functions
Approved in July 2015; Code F41032; Duration 2016-2020
NEWS:Atlas of Average Resonance Capture data
An update of the Atlas of Average Resonance Capture (ARC) data with new systematics for the extracted photon strength functions has been performed by J. Kopecky. Details of the analysis with several examples are published in INDC(NDS)-0738. The data will become available in the online database for Photon Strength Functions which is in preparation.
The 6th workshop of it's kind covered the following topics:
- Nuclear level density
- Gamma-ray strength function
- Phase transitions in mesoscopic systems
- Applications in astrophysics and reactor physics
- Other related topics
A special session was held on Friday 12th May for CRP participants to discuss progress in the CRP tasks. The minutes of the meeting were circulated to all CRP members.
Background information on: CRP on Updating the Photonuclear Data Library and generating a Reference Database for Photon Strength Functions
Photon nuclear data describing interactions of photons with atomic nuclei are of importance for a variety of applications including (i) radiation shielding and radiation transport analyses, (ii) calculation of absorbed does in the human body during radiotherapy, (iii) activation analyses, safeguards and inspection technologies, (iv) nuclear waste transmutation, (v) fission and fusion reactor technologies, and (vi) astrophysical nucleosynthesis.
In response to growing needs for photonuclear data, the IAEA held a Coordinated Research Project (CRP) under the title Compilation and Evaluation of Photonuclear Data for Applications between 1996 and 1999. This CRP produced three major results: the IAEA Photonuclear Data Library; a Handbook on Photonuclear Data for Applications, Cross-sections and spectra. Final report of a co-ordinated research project 1996 - 1999. IAEA-TECDOC-1178, 2000; and additions of compiled experimental photonuclear cross sections in the EXFOR database. The Photonuclear Data Library, that is available at the IAEA Nuclear Data Services web site, includes photon absorption data, total and partial photoneutron reaction cross sections for 164 isotopes, primarily for structural, shielding, biological and fissionable materials.Although this database has been extremely useful to a broad user community, it has become evident that it needs to be revised especially since (i) some of the data are unreliable and discrepant, (ii) for 37 isotopes there exist data that have not been evaluated, (iii) improved evaluation techniques are available, (iv) many new data have been published in recent years.
In addition to the many applications mentioned above, photon strength functions which describe the average response of the nucleus to an electromagnetic probe, are important for the theoretical modelling of nuclear reactions, consequently they are relevant sources of information for other databases such as the IAEA Reference Input Parameter Library (RIPL), and evaluated data files such as Evaluated Gamma Activation File (EGAF), Evaluated Nuclear Structure Data File (ENSDF), and transport files in ENDF-6 format which are also supported by the IAEA. In the past two decades, there has been considerable growth in the amount of reaction data measured to determine integrated photon strength functions. Quite often the different experimental techniques lead to discrepant results and users are faced with the dilemma of trying to decide which (if any) amongst the divergent data they should adopt. It is therefore important that all these experimental data are evaluated by experts who will recommend the most reliable data for use in the various applications.
To address all these data needs an IAEA Consultants' Meeting on 'Compilation and Evaluation of reaction gamma-ray data' was held in November 2013. A summary report of the CM was published as technical report INDC(NDS)-0649. The Consultants Meeting strongly recommended a new CRP to revise the photonuclear data library and generate a dedicated database of compiled and evaluated/recommended photon strength functions. The scope and deliverables of such an activity are discussed in detail in this document. The proposed CRP was endorsed by the Nuclear Data Section advisory body, the International Nuclear Data Committee (INDC), in June 2014. Aspects of the proposed project were presented at CGS15 - Capture Gamma-ray Spectroscopy and Related Topics, 25-29 August 2014, Dresden (published in EPJ Web of Conferences 93, 06004 (2015); DOI:10.1051/epjconf/20159306004).
The main goals of the CRP are to
- update the Photonuclear Data Library (1999)
- generate a Reference Database for Photon Strength Functions.
Specific Research Objectives
- Measure photonuclear cross-section data where needed
- Update existing evaluations and evaluate new photonuclear data (including total photoabsorption cross sections, partial photonuclear cross sections and photoneutron spectra)
- Measure photon stength functions where needed
- Compile, assess and evaluate existing photon ptrength function data
- Develop and use theoretical tools to make recommendations and extrapolations to mass regions where no data exist
- Propose new measurements where needed.
1st RCM, 4-8 April 2016
The 1st Research Coordination Meeting of the CRP was held from 4-8 April 2016, at the IAEA, Vienna. The meeting addressed the work plans of the CRP participants, and also additional joint actions that need to be taken in order to achieve the goals of the CRP. More information about the meeting is available here.