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Plasma Optimization in a Multicusp Ion Source by Using a Monte Carlo Simulation
M. Hosseinzadeh,H. Afarideh 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.63 No.7
A Monte Carlo simulation code has been developed to optimize the number of magnets confiningthe plasma in the H- multicusp ion source. This code improves the existing drawbacks in the particlestudio CST program and predicts the lifetime of primary electrons and the effects of collisions ofelectrons and hydrogen gas atoms. In this simulation are found 12 cusps to provide the highestplasma intensity in our configuration. Finally, our developed code is validated by simulating theexperimentally-tested KSTAR ion-source configuration and semi-empirical equation.
Magnet Design for the 10MeV AVF Cyclotron Accelerator
R. Solhju,H. Afarideh,M. Ghergherehchi,채종서 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.63 No.7
In this paper, an azimuthally varying field (AVF) magnet is designed to produce a 10 MeV protonbeam. In order to design and analyze the magnet three-dimensionally, we use the CST program. Also, field mapping results have been obtained by using the CST program and the MATLABprogram to validate the precision of the design. In addition, an iterative process is conducted formagnet shimming. The precision of this design is ensured by using the optimization part of CSTto optimize parameters like the number of mesh cells, the boundary dimension, etc.
M. Kazemi,H. Afarideh,Z. Riazi 한국물리학회 2015 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.67 No.9
The aim of this research work is to use a better parallel software structure to improve the performance of the Monte Carlo Geant4 code in proton treatment planning. The hadron therapy simulation is rewritten to parallelize the shared memory multiprocessor systems by using the Message-Passing Interface (MPI). The speedup performance of the code has been studied by using two MPI-compliant libraries including Open MPI and the MPICH2, separately. Despite the speedup, the results are almost linear for both the Open MPI and MPICH2; the latter was chosen because of its better characteristics and lower computation time. The Geant4 parameters, including the step limiter and the set cut, have been analyzed to minimize the simulation time as much as possible. For a reasonable compromise between the spatial dose distribution and the calculation time, the improvement in time reduction coefficient reaches about 157.
Nikbakht M.,Afarideh H.,Ghergherehchi M. 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.12
A low-energy dielectric loaded accelerator with a non-uniform, multi-segment structure is studied and optimized. So far, no analytical solution is provided for such structures. Also, due to the existing nonlinear behavior and a large number of geometric parameters, the problem of numerical optimizations is complex. For this reason, a method is presented to design and optimize such structures using the Genetic Algorithm (GA). Moreover, the GA output results are compared with Trust Region (TR) and Nelder-Mead Simplex (NMS) methods. Comparative results show that the GA is more efficient in achieving optimization goals and also has a higher speed than the two other methods. Finally, an optimized accelerating tube is integrated into a proper coupler. Then, the accelerator is simulated for full electromagnetic investigations using the CST suite of codes. This design leads to a structure with a power of about 80 kW in the X-band, which delivers electrons to the output energy in the range of 300e459 kV. The length and outer diameter of the accelerating tube obtained are 10 cm and 1 cm, respectively.