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Leila Mokhtari Oranj,이희석,Mario Santana Leitner 한국물리학회 2017 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.71 No.11
In Korea, a heavy ion accelerator facility (RAON) has been designed for production of rare isotopes. The 90 bending section of this accelerator includes a 1.3-μm-carbon stripper followed by two dipole magnets and other devices. An incident beam is 18.5 MeV/n 238U33+,34+ ions passing through the carbon stripper at the beginning of the section. The two dipoles are tuned to transport 238U ions with specific charge states of 77+, 78+, 79+, 80+ and 81+. Then other ions will be deflected at the bends and cause beam losses. These beam losses are a concern to the devices of transport/beam line. The absorbed dose in devices and prompt dose in the tunnel were calculated using the FLUKA code in order to estimate radiation damage of such devices located at the 90 bending section and for the radiation protection. A novel method to transport multi-charged 238U ions beam was applied in the FLUKA code by using charge distribution of 238U ions after the stripper obtained from LISE++ code. The calculated results showed that the absorbed dose in the devices is influenced by the geometrical arrangement. The maximum dose was observed at the coils of first, second, fourth and fifth quadruples placed after first dipole magnet. The integrated doses for 30 years of operation with 9.5 pμA 238U ions were about 2 MGy for those quadrupoles. In conclusion, the protection of devices particularly, quadruples would be necessary to reduce the damage to devices. Moreover, results showed that the prompt radiation penetrated within the first 60 - 120 cm of concrete.
Study on Radiation Production in the Charge Stripping Section of the RISP Linear Accelerator
오주희,Leila Mokhtari Oranj,이희석,고승국 한국물리학회 2015 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.66 No.3
The linear accelerator of the Rare Isotope Science Project (RISP) accelerates 200 MeV/nucleon238U ions in a multi-charge states. Many kinds of radiations are generated while the primarybeam is transported along the beam line. The stripping process using thin carbon foil leads tocomplicated radiation environments at the 90-degree bending section. The charge distribution of238U ions after the carbon charge stripper was calculated by using the LISE++ program. Theestimates of the radiation environments were carried out by using the well-proved Monte Carlocodes PHITS and FLUKA. The tracks of 238U ions in various charge states were identified usingthe magnetic field subroutine of the PHITS code. The dose distribution caused by U beam lossesfor those tracks was obtained over the accelerator tunnel. A modified calculation was applied fortracking the multi-charged U beams because the fundamental idea of PHITS and FLUKA was totransport fully-ionized ion beam. In this study, the beam loss pattern after a stripping sectionwas observed, and the radiation production by heavy ions was studied. Finally, the performanceof the PHITS and the FLUKA codes was validated for estimating the radiation production at thestripping section by applying a modified method.