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The external radiation hazard
Published in Alan Martin, Sam Harbison, Karen Beach, Peter Cole, An Introduction to Radiation Protection, 2018
Alan Martin, Sam Harbison, Karen Beach, Peter Cole
Two materials currently in use for occupational dose monitoring are lithium fluoride and calcium fluoride. The latter is very sensitive but has a poor energy response. Lithium fluoride is less sensitive, but its energy response is excellent. Moreover, if lithium enriched in the isotope lithium-6 (Li-6) is used, then the dosimeter can be set up to be used as part of a combined neutron/beta-gamma dosimeter. In a practical dosimeter system, the thermoluminescent material is usually in the form of a thin disc.
Radiation Dose Assessment of Tritium Released from the Thorium Molten Salt Reactor
Published in Nuclear Science and Engineering, 2023
Wenyu Cheng, Jie Liang, Mingjun Zhang, Fei Wei, Jinglin Li, Xiaochong Xue, Youshi Zeng, Ke Deng, Qin Zhang, Wei Liu
At present, the main tritium-producing reaction channels of the TMSR under construction are lithium neutron reactions [6Li(n,α)T and 7Li(n,α)T]. Other tritium production reactions are as follows: (1) Very little tritium is produced in other reaction channels, such as B, Be, and F elements [10B(n,2α)T, 10B(n,α)7Li, 9Be(n,α)6He, 9Be(n,α)T, 19F(n,T)16O]; (2) nuclear fuel triple fission reaction; (3) very few neutrons of protium and deuterium capture to produce tritium (relatively negligible).32 Tritium production in these nuclear reactions accounts for a very small amount of tritium production and is extremely complex, and there is reaction competition. Therefore, this paper mainly calculates the amount of tritium produced by lithium [6Li(n,α)T and 7Li(n,α)T].
Development of a neutron beam monitor with a thin plastic scintillator for nuclear data measurement using spallation neutron source
Published in Journal of Nuclear Science and Technology, 2022
Hideto Nakano, Tatsuya Katabuchi, Gerard Rovira, Yu Kodama, Kazushi Terada, Atsushi Kimura, Shoji Nakamura, Shunshuke Endo
The 6Li(n,t)4He reaction is widely used in many types of neutron detectors such as lithium-6 glass scintillators. The reaction cross section reaches 940 b at the thermal neutron energy (23.5 meV). With a positive Q-value of 4.78 MeV, the kinetic energies of tritons and α particles are 2.73 and 2.05 MeV, respectively. These high energy particles are easy to detect and separate from low energy γ-ray background events. The 10B(n,α)7Li reaction is also commonly used for neutron detection but the energies of and 7Li nucleus are not so high (1.47 and 0.84 MeV). Thus, the 6Li(n,t)4He reaction is more suitable for a detection system using a neutron converter film.
Comparing the Effectiveness of Polymer and Composite Materials to Aluminum for Extended Deep Space Travel
Published in Nuclear Technology, 2020
Daniel K. Bond, Braden Goddard, Robert C. Singleterry, Sama Bilbao y León
Figure 11 compares the shielding capabilities of materials containing natural lithium and natural boron with materials containing only the neutron absorbers 6Li and 10B, respectively, for both boundary conditions. Lithium hydride, polyethylene with 30% B, and boron nitride nanotubes do show a slight increase in shielding capability when compared to the materials containing natural lithium and boron, but the increase in not significant. Lithium-6 decreases the exposure by 0.01713 mSv/day (2.97%) for the GCR boundary condition and 6.03 mSv/event (16.00%) for the SPE boundary condition. Boron-10 within boron nitride nanotubes decreased the exposure by 0.0116 mSv/day (1.56%) for GCRs and 2.88 mSv/event (5.04%) for SPEs. Boron-10 within polyethylene with 30% boron decreased the exposure by 0.01 mSv/day (0.90%) for GCRs and 1.196 mSv/event (3.22%) for SPEs.