Cyclotron is a kind of the radio frequency accelerators, in which electric field is used to accelerate the particles, and magnetic field is applied to confine its path in a circular way. Cyclotron is usually used to accelerate positive charged ions. The main components of the accelerator are electromagnet, ion source, vacuum system and radio frequency supply. Department of physics of IUT in cooperation with the central laboratory, perform a project of manufacturing a cyclotron at Isfahan University of Technology. The subject of this thesis is design and simulation of the Penning Ion Guage (PIG) for the cyclotron. At first, an overview of the different ion sources is presented, then CST software is studied to simulate the ion source. In order to optimize the geometry and parameters of the ion source, the production of the secondary electrons that generate ions is investigated. Then, the effects of the parameters such as size and magnetic field on the density of the plasma in the ion source are studied. We have shown that tapered anode increases the secondary electrons compare with cylindrical one. The optimum conditions to produce secondary electrons were given: 3.5 mm for inner radius of tapered anode, 5 mm for radius of cathode, 0.2 Tesla for magnetic field and tantalum for the cathode material. The cyclotron magnet was designed with 1T field strength. The variation of the magnetic field and magnetic hardness parameter with respect to the size of the magnetic poles were investigated. Then the final kinetic energy of the particle for different diameters were evaluated. However magnetic field is decreased by increasing the radius of the poles, magnetic hardness parameter is increased. Therefore the kinetic energy of particle is increased. After that, the magnetic field was measured with and without copper Dee. The presence of Dee decreased the magnetic field. In the following, the ion source with cylindrical and tapered anode geometry considered within 1T field designed in CST software and the effect on the secondary electron production was compared.