NBS (National Bureau of Standards) measurement services: neutron-source-strength calibrations. Final report

The manganese sulfate (MnSO/sub 4/) bath method of neutron source strength calibration at NBS is described and compared briefly with other MnSO/sub 4/ bath techniques used internationally. The accuracy of source intercomparisons and practical limitations of the NBS system. In particular, there is discussion of uncertainties associated with system limitations and with corrections necessary for neutron capture in the source, capture of fast and thermal neutrons by competing reactions in the MnSO/sub 4/, capture of neutrons in the source container, and the correction for leakage of neutrons from the bath, which is 1.27 meters in diameter.