Isotope dilution mass spectrometry of 10B and 6LiF reference deposits used for the determination of the neutron lifetime
The accurate characterisation of 10B and 6LiF reference deposits is of the greatest importance in absolute neutron counting, e.g. for the determination of the lifetime of the free neutron. A series of 10B and 6LiF deposits with different surface densities was prepared on silicon substrates by vacuum deposition and analysed by isotope dilution mass spectrometry (IDMS), subsequent to their relative characterisation by neutron induced charged particle counting and determination of their surface area. The IDMS results were performed to calibrate the (n, alpha) measurements. They carry a total uncertainty (1s equivalent) on the number of 10B atoms in the deposit of 0.48% on Series I (without chemical purification) and 0.58% on Series II (with chemical purification). The corresponding uncertainty on the number of 6Li atoms in the deposit is 0.25%. The systematic components of these uncertainties are 0.12% on the 10B content and 0.21% on the 6Li content. An intercomparison on the basis of the count rates of the (n, alpha) measurements, the surface areas and the IDMS results shows an excellent agreement between the results for 10B and 6Li.
Bibliographic Reference: Article: International Journal of Mass Spectrometry and Ion Processes, Vol. 108 (1991) pp. 189-198
Record Number: 199111635 / Last updated on: 1994-12-02
Original language: en
Available languages: en