Accession Number : AD0445239


Title :   A NEW THERMAL NEUTRON FLUX DENSITY STANDARD


Corporate Author : NATIONAL RESEARCH COUNCIL OF CANADA OTTAWA (ONTARIO) DIV OF APPLIED PHYSICS


Personal Author(s) : Hargrove, C K ; Geiger, K W


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/445239.pdf


Report Date : 30 Jan 1964


Pagination or Media Count : 14


Abstract : Six Am241-Be(alpha,n) neutron sources are arranged around the central circumfejence of a graphite cylinder 28 cm in diameter by 26.5 cm high. This assembly is surrounded by 10 cm of polyethylene. The graphite cylinder contains an accessible central cavity, 5 cm in diameter by 5 cm high, for the calibration of thermal neutron detectors. The thermal neutron flux density in the cavity is measured by 4 pi beta-gamma coincidence counting of irradiated gold foils. A flux density below cadmium cutoff of nthvo= 8700/sq cm/sec (=1.5%) was found. The uniformity is shown to be constant within the cavity to better than =0.5% over a cylindrical volume 5 cm in diameter by 2 cm high.


Descriptors :   *NEUTRON FLUX , *THERMAL NEUTRONS , *NEUTRON DETECTORS , CALIBRATION , FOILS(MATERIALS) , BERYLLIUM , GOLD , RADIOACTIVE ISOTOPES , RADIOACTIVE DECAY , COINCIDENCE COUNTING , ALPHA PARTICLE REACTIONS , AMERICIUM , STANDARDS , DENSITY , SOURCES , REPRINTS


Subject Categories : Fission Reactor Physics


Distribution Statement : APPROVED FOR PUBLIC RELEASE