New bonner sphere response matrix, ARK1, for neutron spectral unfolding

Journal Article · Tue Dec 31 04:00:00 EST 1996 · Transactions of the American Nuclear Society

OSTI ID:436975

Lemley, E C; West, L ^[1]

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1. Univ. of Arkansas, Fayetteville, AR (United States)

Although the energy spectra of neutron radiation cannot be measured directly, knowledge of the neutron spectrum in the workplace is necessary for predictions of personnel radiation doses and shielding design. Bonner spheres consist of a central detector over which polyethylene moderating spheres are placed, permitting measurement of the counting rate for various combinations of the central detector and several moderators. The process of approximating neutron spectra from Bonner sphere count-rate data is known as spectral unfolding and requires knowledge of the energy response of each detector-moderator combination (i.e., a response function). The unfolding process may be sensitive to small changes because the response functions are usually ill conditioned making an accurate set of response functions vital to the unfolding process. Previous response function calculations have been limited to a one-dimensional model of the detector-moderator combination and to binned cross-section sets, already averaged over some representative energy spectrum. Of these available response matrices, UTA4 and SAN4 perform the best in unfolding tests. This paper focuses on the relative performance differences between previously published response functions and those we have calculated by modeling Bonner spheres in three dimensions with the Monte Carlo code MCNP4A.

• OSTI ID: 436975
• Report Number(s): CONF-9606116--
• Journal Information: Transactions of the American Nuclear Society, Journal Name: Transactions of the American Nuclear Society Vol. 74; ISSN 0003-018X; ISSN TANSAO
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
44 INSTRUMENTATION
INCLUDING NUCLEAR AND PARTICLE DETECTORS
66 PHYSICS
99 GENERAL AND MISCELLANEOUS
BONNER SPHERE DETECTORS
DESIGN
ENERGY SPECTRA
M CODES
NEUTRON SPECTRA
NEUTRON TRANSPORT
PERFORMANCE
RADIATION DOSES
RESPONSE FUNCTIONS
SHIELDING