Photon dose mixed in monoenergetic neutron calibration fields using 7Li(p,n)7Be reaction.
The ambient dose equivalents H*(10) of photons mixed in the 144, 250 and 565 keV monoenergetic neutron fields were evaluated using measurements from an NaI(Tl) detector and calculations done using the MCNP-ANT code. It was found that H*(10) of the photons produced in the target assembly dominates the dose, particularly near the target. The H*(10) of the photons produced in other materials in the field increases with the increase in distance from the target and could not be neglected at a large distance from the target. The ratios of the H*(10) of the mixed photons to that of the monoenergetic neutrons for 144, 250 and 565 keV neutron fields, were evaluated to be below 5.5, 6.9 and 1.5 %, respectively. The ratios were calculated at calibration points between 100 and 500 cm from the target.
Department of Radiation Protection, Nuclear Science and Research Institute, Japan Atomic Energy Agency, 2-4 Shirakata-Shirane, Tokai, Ibaraki 319-1195, Japan tanimura.yoshihiko@jaea.go.jp.
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Tanimura
Department of Radiation Protection, Nuclear Science and Research Institute, Japan Atomic Energy Agency, 2-4 Shirakata-Shirane, Tokai, Ibaraki 319-1195, Japan.
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Tsutsumi
Department of Radiation Protection, Nuclear Science and Research Institute, Japan Atomic Energy Agency, 2-4 Shirakata-Shirane, Tokai, Ibaraki 319-1195, Japan.
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Yoshizawa
D002138:Calibration; D004867:Equipment Design; D008094:Lithium / Q000737:chemistry*; D009010:Monte Carlo Method; D009502:Neutrons; D017785:Photons; D011522:Protons; D011829:Radiation Dosage; D011835:Radiation Protection; D011874:Radiometry / Q000295:instrumentation* / Q000379:methods; D015203:Reproducibility of Results
D011522:Protons; D008094:Lithium