International key comparison of 24 keV neutron fluence measurements (1993–2009): CCRI(III)-K1

• Published in: Metrologia 2010-01, Vol.47, p.06014-06014
• Main Authors: Thomas, D J, Lewis, V E, Klein, H, Allisy-Roberts, P J
• Format: Article
• Language: English
• Subjects: Calibration; Confidence intervals; Consistency; Fluence; Mathematical analysis; Spectra; Texts
• ISSN: 0026-1394
• DOI: 10.1088/0026-1394/47/1A/06014

A comparison of 24.5 keV neutron fluence standards was organized by Section III (Neutron Measurements) of the Comite Consultatif des Rayonnements Ionisants, (CCRI). The exercise involved the circulation of a set of three different-diameter Bonner spheres for calibration in fields with energies around 24.5 keV. The fields were produced using four different methods of neutron production. The responses (counts per unit neutron fluence) of the individual spheres were initially determined for the neutron energy of the production method, or methods, employed. To derive the 24.5 keV responses, it was necessary to make corrections for spectral effects, and these were achieved by using response functions for the spheres calculated using the code MCNP. The results demonstrate good consistency within the estimated uncertainties (ranging from about 5% to 10% at the 95% confidence level) between the results reported by all the participants. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI Section III, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).