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Irradiation
Published in David A. Cardwell, David C. Larbalestier, Aleksander I. Braginski, Handbook of Superconductivity, 2023
Of course, there is also another “side of the coin”. All kinds of radiation techniques generally lead to induced radioactivity in the sample. In the case of Ag-sheathed PIT tapes, 110Ag is significantly activated by thermal neutrons. However, by optimising the content of 235U in the tapes, the exposure time to the neutron beam can be significantly reduced (while keeping the number of fission tracks the same), thus alleviating the problem considerably. The overall radioactivity is much smaller than in the case of proton induced fission of the Bi nuclei in the tapes. This and the much easier availability of neutron beams (even over large volumes) certainly make the addition of uranium a highly attractive technique. Although considerable progress in current carrying capabilities of these tapes has been reported during the past few years, no progress in terms of flux pinning optimisation as described above could be achieved by means of chemical doping.
Properties and Characteristics of Water and Wastewater
Published in Donald R. Rowe, Isam Mohammed Abdel-Magid, Handbook of Wastewater Reclamation and Reuse, 2020
Donald R. Rowe, Isam Mohammed Abdel-Magid
Induced radioactivity— Radioactivity produced in a substance after bombardment with neutrons or other particles. The resulting activity is “natural radioactivity” if formed by nuclear reactions occurring in nature, and “artificial radioactivity” if the reactions are caused by man.
Measurement and simulations of high-energy neutrons through a various thickness of concrete and steel shields using activation detectors at CHARM and CSBF
Published in Journal of Nuclear Science and Technology, 2023
Noriaki Nakao, Toshiya Sanami, Tsuyoshi Kajimoto, Hiroshi Yashima, Robert Froeschl, Davide Bozzato, Elpida Iliopoulou, Angelo Infantino, Eunji Lee, Takahiro Oyama, Masayuki Hagiwara, Seiji Nagaguro, Tetsuro Matsumoto, Akihiko Masuda, Yoshitomo Uwamino, Arnaud Devienne, Fabio Pozzi, Marco Tisi, Tommaso Lorenzon, Nabil Menaa, Heinz Vincke, Stefan Roesler, Markus Brugger
Recently, a number of particle accelerator facilities have been constructed for physics research, medical irradiation, and industrial use. Accordingly, accelerator specifications have been upgraded to enhance the intensity and energy of the particle beam, providing better statistics of measurements and more efficient irradiation. To ensure the radiation safety in such facilities, the induced radioactivity and prompt radiation levels must be predicted from the data of secondary neutrons generated by beam irradiation. Because of the strong penetrability of produced neutrons, these accelerator facilities require massive shields to suppress the radiation levels outside the facility. As the radiation shield consumes a considerable portion of the total construction costs, the shielding design is very important when constructing high-intensity, high-energy accelerator facilities.
Radiological Characterization with a Fluence Conversion Coefficients–Based Method: A Practical Example of the Preparatory Studies to the Pilot Beam at the CERN Large Hadron Collider
Published in Nuclear Science and Engineering, 2023
Davide Bozzato, Robert Froeschl
At high-energy accelerator facilities, like the ones that are part of the accelerator complex at the European Organization for Nuclear Research (CERN), the typical radiation fields are mixed, that is they are characterized by the presence of various particle species whose energies can span from thermal energies up to hundreds or even thousands of GeV. Induced activation in components exposed to primary or stray radiation is primarily caused by charged hadrons (predominantly protons and charged pions); neutrons; and, in certain conditions, even photons. Monte Carlo radiation transport codes like the FLUktuierende KAskade (FLUKA) code[1,2] and the Particle and Heavy Ion Transport Code System (PHITS)[3,4] are widely employed to face the challenges of estimating production yields and induced radioactivity for these complex problems. Traditional methods based on Monte Carlo simulations can be classified either as event-based methods or fluence-based methods and are briefly recalled in Sec. I.A. The main principles of the complementary approach based on fluence conversion coefficients are instead summarized in Sec. I.B
Radiation Protection at Petawatt Laser-Driven Accelerator Facilities: The ELI Beamlines Case
Published in Nuclear Science and Engineering, 2023
Anna Cimmino, Veronika Olšovcová, Roberto Versaci, Dávid Horváth, Benoit Lefebvre, Andrea Tsinganis, Vojtěch Stránský, Roman Truneček, Zuzana Trunečková
Several tasks are performed by means of Monte Carlo simulations. One of the most relevant is the characterization of radiation field maps based on source terms agreed upon with the experimental teams and relying on either extrapolation from previous experiments with similar conditions or particle-in-cell simulations. Radiation field maps are generated for several quantities, like H*(10), HEH fluence, and Si-1 MeV neq fluence, and are then used for the assessment of the risk for humans and machines. The identification and the design of possible mitigation options are also based on Monte Carlo simulations. This includes identifying more suitable locations for devices and the design of radiation shielding. Additionally, FLUKA simulations are used to estimate the possible induced radioactivity of materials exposed to the radiation generated in laser-target interactions and advanced planning for the management of the activated materials. In fact, FLUKA offers unique capabilities for activation studies as the prompt and residual radiation particle cascades are simulated in parallel and are based on microscopic models for nuclide production and analytical solutions of the Bateman equations for activity buildup and radioactive decay.32,33