DECY-13 cyclotron is a radioisotope production cyclotron developed by PSTA. In a cyclotron, it is important to understand magnetic fields and electric field distribution for the proton beam trajectories. This paper describes the distribution of the magnetic field from the experimental measurement. Magnetic field has been converted into 3-dimensional data by extrapolation. Data validation was done by comparing the Opera3D simulation and used in simulations of the beam trajectories. Simulations were carried out by using Scilab 5.4.1 and the Runge-Kutta (RK4) approximation method. The parameters used in DECY-13 cyclotron were 40 kV Dee voltage with a radiofrequency (RF) 77.66 MHz and a fourth-harmonics type. The calculations and simulations result showed the beam could pass through the puller at the distance of the ion source with a puller was 6 mm and the optimum distance of 4 mm. The largest difference in error at z = 6 mm was 0.023 T of the average magnetic field 1.275 T. The phase acceptance in horizontal and vertical motion in the central region was about 38 Degrees from -19° to 19°. This experimental and simulation data could be used as a reference for DeCY-13 cyclotron magnetic and electric field distribution profiles.

) beam in a 13 MeV PET cyclotron (DECY-13) were carried out by using the Runge-Kutta (RK4) approximation method and Scilab 5.4.1. The magnetic and electric fields were calculated using Opera-3d/TOSCA softwares at 1 mm resolution. The cyclotron is of a fourth-harmonics type, meaning that the acceleration occurs four times per cycle, with a radiofrequency (RF) field of 77.66 MHz frequency and 40 kV amplitude. The calculations and simulations show that the maximum distance between the ion source and the puller is about 6 mm, while the maximum width of the beam at 13 MeV is about 10 mm, and the initial phase between the RF field and the beam ranges from -10° to 10°, with a yield of about 10% of the beam from the ion source getting accelerated to 13 MeV.

Optimization of the ion source head position of the DECY-13 Cyclotron in the central region has been carried out based on simulation process using a particle tracking program written in Scilab 5.2.1. The simulated particle was the H -ion that was accelerated in DECY-13 Cyclotron. The input for the program were the magnetic field and the electric field in the central region that were calculated by Opera-3D software package and TOSCA module. The optimized position of ion source head position is in a radius of 2 cm relative to the zero point of the magnet and at a distance of 4 mm relative to the puller. This result can be useful for determining the configuration of the parts in the central region when it is tested for generating the first ion beam in the future.

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–Using OPERA3DTM, the magnet poles’ shimming that provide an isochronous magnetic field in DECY-13 cyclotron was designed and calculated. The shimmed magnet poles as designed were placed in the magnet and the distribution of the magnetic field in the magnet axis direction (Bz) was measured in radial ( x and y) directions using 2 probes covering x=0 to 480 mm for one probe and 481 to 960 mm  for the other, and y=0 to 960 mm, all were done at z=0 in 9 hours of scanning at 5 mm steps. This paper describes the interpolation and extrapolation to obtain data for magnetic field components (Bx, By,Bz) at 1 mm resolution and at z≠0 as required for beam tracking simulations. The tracking results are used to evaluate the distribution of the shimmed magnetic fields of DECY-13. The program for the interpolation and extrapolation was written and run using a free software Scilab 5.4.1, and tested against OPERA3DTM design data. The beam can reach final energy of 13 MeV when both data was applying in the beam tracking simulation.. However when the measured data was used, the final energy of the beam  reached only 3 MeV, meaning that at the place where that energy was reached the magnetic field is no longer is of isochronous and the shimming of the magnetic poles’ must be improved or redesigned to reach the final beam energy of 13 MeV.Key words: isochronous, DECY-13 cyclotron, Scilab 5.4.1, interpolation and extrapolation, beam tracking simulation