Computer and experimental modeling of target performance in particle beams and fusion or fission environments

• Published in: Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment Accelerators, spectrometers, detectors and associated equipment, 2002-03, Vol.480 (1), p.137-155
• Main Authors: Koptelov, E.A., Lebedev, S.G., Matveev, V.A., Sobolevsky, N.M., Strebkov, Yu.S., Subbotin, A.V.
• Format: Article
• Language: English
• Subjects: Accelerator-driven target; Computer modeling; Experimental modeling; Radiation damage
• ISSN: 0168-9002; 1872-9576
• DOI: 10.1016/S0168-9002(01)02083-6

Computer simulation of target performance in particle beams for fusion or fission irradiation is considered. Such simulation is realized by means of a set of Russian computer codes SHIELD, RADDAM, etc. The set can permit the full modeling of irradiation conditions of any possible installation in terms of such parameters as: • point defect generation by irradiation; • rate of accumulation of He atoms produced in nuclear reactions; • rate of accumulation of H atoms; • spectra of primary knock-on atoms in collision displacements and • temperature of the sample under irradiation. The evidence of possibilities for the modeling of different irradiation conditions (for example, fusion) at the RADEX facility of the INR RAS is presented. RADEX is the irradiation channel located inside the proton target of the beam stop of the INR RAS linear proton accelerator with energy up to 600 MeV. The proton target is situated in the bottom part of target's cylindrical container and is formed by tungsten plates, which are covered with a titanium coating and cooled by light water. The RADEX irradiation channel is located asymmetrically relatively to the vertical axis of the cylinder. The proton beam enters the irradiation channel through the aluminum alloy first wall, having passed through some of the tungsten plates, all of thickness ∼4 cm. Besides the proton flux, the irradiation channel is subjected to a neutron flux of a spallation spectrum. The location of the irradiation channel of the RADEX facility can be changed by rotation of the proton target about the vertical axis. There are six possible different positions of the irradiation channel, with angles of 0°, 60°, 120°, 180°, 240°, 300°, 360° relative to the proton beam direction. In the position 0, the proton and neutron fluxes are maximal in the irradiation channel, and the spectrum of primary knock-on atoms in the irradiated sample will be very hard due to the predominance of high-energy protons in the irradiation field. The spectrum can be significantly softened by means of rotation of the proton target around the vertical axis. Spectrum softening will also occur when the sample moves upwards in the irradiation channel away from the proton beam line. This gives us the possibility to change all five irradiation parameters pointed out above to model almost any possible irradiation installation. The example of computer modeling for the irradiation conditions of the ITER fusion device at the RADEX facility is presented.