Neutron penetration through iron and concrete shields with the use of 22. 0- and 32. 5-MeV quasi-monoenergetic sources

Journal Article · Fri Apr 01 04:00:00 EST 1994 · Nuclear Science and Engineering; (United States)

OSTI ID:7103664

Ishikawa, Toshio ^[1]; Miyama, Yukio; Nakamura, Takashi ^[2]

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1. Fujita Corp., Yokohama (Japan). Technical Research Institute
2. Tohoku Univ., Sendai (Japan). Cyclotron and Radioisotope Center

For the first time, spectra in the range of 34 MeV down to 0.4 eV for neutrons that penetrated through iron and concrete shields were measured with the use of quasi-monoenergetic sources generated from a [sup nat]Li(p,n)Be reaction. The source neutrons were produced by the bombardment of 35- and 25-MeV protons on a 2-mm-thick natural lithium target and were measured by the time-of-flight method. The neutrons that penetrated through the shields were measured by an NE-213 scintillator, a proton recoil proportional counter, and a spherical multimoderator spectrometer, i.e., the Bonner Ball, and were analyzed to energy spectra by the unfolding methods. The attenuations of a peak fluence, a total fluence, and a dose equivalent were also analyzed. Monte Carlo calculations using the MORSE-CG code were carried out with the multigroup cross-section library DLC-119/HILO86 and the original version, DLC-87/HILO, to evaluate the cross sections by comparison with the measurement. The results of the calculation indicated the following. On the whole, the calculated neutron spectra agreed with the experimental spectra above 10 odd MeV but gave an underestimation below that value. The peak fluence attenuation length for 22-MeV neutrons that penetrated through the iron shield was overestimated by DLC-87 but corrected by DLC-119. The dose-equivalent attenuation lengths almost agreed with the measurement for the concrete shield. On the other hand, those for the iron shield were underestimated.

• OSTI ID: 7103664
• Journal Information: Nuclear Science and Engineering; (United States), Journal Name: Nuclear Science and Engineering; (United States) Vol. 116:4; ISSN NSENAO; ISSN 0029-5639
• Country of Publication: United States
• Language: English

Related Subjects

663610* -- Neutron Physics-- (1992-)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ACCELERATORS
ATTENUATION
BARYONS
BUILDING MATERIALS
COMPUTER CALCULATIONS
COMPUTER CODES
CONCRETES
ELEMENTARY PARTICLES
ELEMENTS
FERMIONS
HADRONS
IRON
M CODES
MATERIALS
METALS
NEUTRAL-PARTICLE TRANSPORT
NEUTRON FLUENCE
NEUTRON SPECTRA
NEUTRON TRANSPORT
NEUTRONS
NUCLEONS
RADIATION TRANSPORT
SHIELDING
SPECTRA
TRANSITION ELEMENTS