Roberts, N J; Horwood, N A; Vykydal, Z; Park, H; Kim, J; Pereira, W W; da Fonseca, E S; Thiam, C; Hui, Z; Dewey, M S; Mumm, H P; Harano, H; Matsumoto, T; Masuda, A; Manabe, S; Archambault, J P; Moiseev, N N; Didyk, A V (2024) International comparison of measurements of neutron source emission rate (2016-2021) - CCRI(III)-K9.Cf.2016. Metrologia, 61 (1A). 06001 ISSN 0026-1394

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Abstract

Section III (neutron measurements) of the Comité Consultatif des Rayonnements Ionisants, CCRI, conducted a comparison of primary measurements of the neutron emission rate of a 252 Cf radionuclide source. A single 252 Cf source was circulated to all participants between 2016 and 2020. Ten laboratories participated -CMI (Czech Republic), KRISS (Republic of Korea), IRD/LNMRI (Brazil), LNE-LNHB (France), NIM (China), NIST (USA), NMIJ (Japan), NPL (UK), NRC (Canada) and VNIIM (Russia) - with NPL making their measurements at the start and repeating them at the end of the exercise to verify the 250 Cf content of the source. Each laboratory reported the emission rate into 4π sr together with a detailed uncertainty budget. All participants used the manganese bath technique except NMIJ who used a relative method based on measurements with a 3 He detector in a graphite pile. VNIIM also made measurements using an associated particle technique. CMI, KRISS, LNE-LNHB, NIM, NPL and VNIIM also measured the anisotropy of the source although this did not formally form part of the comparison.

Item Type:	Article
Keywords:	neutron comparison, emission rate, californium, manganese bath
Subjects:	Ionising Radiation > Neutron Metrology
Divisions:	Medical, Marine & Nuclear
Identification number/DOI:	10.1088/0026-1394/61/1A/06001
Last Modified:	25 Mar 2026 15:34
URI:	https://eprintspublications.npl.co.uk/id/eprint/10362