Update of X-ray and Gamma-ray Decay Data
Standards for Detector Calibration and Other Applications

A Coordinated Research Project (Update of X-ray and γ-ray Decay Data Standards for Detector Calibration and Other Applications) was initiated by the IAEA in the late 1990s to discuss the quality of the relevant data, define a suitable programme to resolve various issues, and produce a new set of recommended data [1]. Participants in the programme were specialists in γ-ray spectroscopy and in the related areas of standards and data evaluation. The primary objective of the resulting CRP was to produce a recommended set of decay parameters for selected radionuclides and nuclear reactions judged as important for the efficiency calibration of equipment used to detect and quantify X- and γ-ray emissions over a range of applications.

Members of the Coordinated Research Project (CRP) reviewed and modified the list of radionuclides most suited for detector calibration, and were able to include some of the specific needs of such nuclear applications as safeguards, materials analysis, environmental monitoring, nuclear medicine, waste management and dosimetry [2 - 4]. A final set of recommended half-lives and X- and γ-ray emission probabilities were agreed upon after much evaluation work had been undertaken. All evaluations were based on the available experimental data, supplemented with the judicious use of well-established theory. The three types of data were compiled and evaluated (half-lives, energies, and emission probabilities). Consideration was also given to the use of the γ - γ coincidence technique for efficiency calibrations, as well as adopting a number of prompt high-energy γ-rays from specific nuclear reactions. A well-defined evaluation procedure was applied to determine the recommended half-lives and emission probabilities for all prominent X- and γ-rays emitted by each selected radionuclide.

Participants

Participants in the CRP were as follows:

Marie-Martine Bé, BNM-CEA/LNHB, Centre d'Etudes Nucleaires de Saclay, Gif-sur-Yvette, France;
Valery P. Chechev, V.G. Khlopin Radium Institute, St. Petersburg, Russian Federation;
Otaviano A.M. Helene and Vito R. Vanin, Departamento de Física Experimental, Instituto de Física, Universidade de São Paulo, São Paulo, Brazil;
Richard G. Helmer, Idaho National Laboratory, Idaho Falls, USA;
Stanislav Hlavác, Institute of Physics, Slovak Academy of Sciences, Bratislava, Slovakia;
Andrzej Marcinkowski, Department of Nuclear Reactions, The Andrzej Soltan Institute for Nuclear Studies, Warsaw, Poland;
Gabor L. Molnár, Department of Nuclear Research, Institute of Isotope and Surface Chemistry, Budapest, Hungary;
Alan L. Nichols, AEA Technology plc, Harwell, UK;
Eckart Schönfeld and Rainer Dersch, Physikalisch Technische Bundesanstalt, Braunschweig, Germany;
Michael J. Woods, Centre for Ionising Radiation Metrology, National Physical Laboratory, Teddington, UK;
Michal Herman, IAEA Nuclear Data Section, Vienna, Austria.

Co-workers have also played important roles in ensuring that the agreed decay-data evaluations have been undertaken:

Coral M. Baglin and Edgardo Browne, Lawrence Berkeley National Laboratory, USA;
Rui M. Castro and Paulo R. Pascholati, Departamento de Física Experimental, Instituto de Física, Universidade de São Paulo, São Paulo, Brazil;
Vanessa Chisté and Cecile Morillon, BNM-CEA/LNHB, Centre d'Etudes Nucleaires de Saclay, Gif-sur-Yvette, France;
Sean M. Collins, T. Desmond MacMahon and Simon A. Woods, Centre for Ionising Radiation Metrology, National Physical Laboratory, Teddington, UK;
Andrey G. Egorov and Nikolay K. Kuzmenko, V.G. Khlopin Radium Institute, St. Petersburg, Russian Federation;
B. Marianski, Department of Nuclear Reactions, The Andrzej Soltan Institute for Nuclear Studies, Warsaw, Poland;
Victor O. Sergeev, Research Institute of Physics, St. Petersburg State University, St. Petersburg, Russian Federation.

Concluding Remarks

A major aim has been to re-define a data file that would be internationally accepted so as to improve the uniformity of subsequent measurements of photon emission probabilities. Thus, the CRP has defined an evaluation methodology that provides consistent and high quality results. Furthermore, it is expected that γ-ray spectroscopists will be willing to accept the standard values presented in this report and use the recommended data in their work. Detailed descriptions of the various evaluations and recommended decay data can be found in the final technical report (Volume 1, Volume 2, Volume 1+2 ).

Efforts to improve many of the recommended decay data to be found on this web site continue through the Decay Data Evaluation Project under the coordination of Laboratoire National Henri Becquerel (LNHB), France. These studies are outlined in some detail in refs. [5, 7].

References

[1] NICHOLS, A., HERMAN, M., Report on the Consultants' Meeting on Preparation of the Proposal for a Co-ordinated Research Project to Update X- and γ-ray Decay Data Standards for Detector Calibration, IAEA Vienna, 24-25 November 1997, INDC(NDS)-378, May 1998.

[2] HERMAN, M., NICHOLS, A., Summary Report of the First Research Co-ordination Meeting: Update of X- and γ-ray Decay Data Standards for Detector Calibration and Other Applications, IAEA Vienna, 9-11 December 1998, INDC(NDS)-403, July 1999.

[3] HERMAN, M., NICHOLS, A., Summary Report of the Second Research Co-ordination Meeting: Update of X- and γ-ray Decay Data Standards for Detector Calibration and Other Applications, PTB Braunschweig, Germany, 10-12 May 2000, INDC(NDS)-415, September 2000.

[4] HERMAN, M., NICHOLS, A.L., Summary Report of the Third Research Co-ordination Meeting: Update of X- and γ-ray Decay Data Standards for Detector Calibration and Other Applications, IAEA Vienna, 21-24 October 2002, INDC(NDS)-437, December 2002.

[5] BÉ, M.-M., CHISTÉ, V., DULIEU, C., BROWNE, E., CHECHEV, V., KUZMENKO, N., HELMER, R., NICHOLS, A., SCHÖNFELD, E., DERSCH, R., Table of Radionuclides, Vol. 1 - A = 1 to 150, Monographie BIPM-5 (2004) Bureau International des Poids et Mesures.

[6] BÉ, M.-M., CHISTÉ, V., DULIEU, C., BROWNE, E., CHECHEV, V., KUZMENKO, N., HELMER, R., NICHOLS, A., SCHÖNFELD, E., DERSCH, R., Table of Radionuclides, Vol. 2 - A = 151 to 242, Monographie BIPM-5 (2004) Bureau International des Poids et Mesures.

[7] BÉ, M.-M., CHISTÉ, V., DULIEU, C., BROWNE, E., BAGLIN, C., CHECHEV, V., KUZMENKO, N., HELMER, R., KONDEV, F., MACMAHON, D., LEE, K.B., Table of Radionuclides, Vol. 3 - A = 3 to 244, Monographie BIPM-5 (2006) Bureau International des Poids et Mesures.