The e-beam produced by the high-energy electron accelerator has a relatively small penetrating power. To increase the penetrating power, a converter must convert the e-beam energy into bremsstrahlung x-rays. This research aims to determine the optimum thickness of tantalum, tungsten, and lead as a converter of e-beam energy into bremsstrahlung x-rays at a 10 MeV high-energy electron accelerator. The optimum thickness of tantalum, tungsten, and lead is determined using simulation with MCNPX software. The electron source modeling with an energy of 10 MeV is made in the form of a flat plane with a size of 120 cm by 10 cm at a distance of 1 mm from the converter. The converter has dimensions of 160 cm by 24 cm and its thickness varies from 1 - 7.5 mm. Then two planar detectors are placed at a distance of 2 cm in front and behind the converter. The simulation results show that the optimum thickness for tantalum, tungsten, and lead converter is 2.0 mm, 1.8 mm, and 2.8 mm respectively. The maximum forward scattered bremsstrahlung x-rays energy are 2.1137 MeV, 2.1287 MeV, and 2.1850 MeV, respectively. And the maximum conversion efficiency is 21.137%, 21.287%, and 21.850%, respectively. These results can be used as a reference in the design of the converter for the 10 MeV high-energy electron accelerator.

A Bremsstrahlung converter for medical apparatuses sterilization has been designed using tantalum and stainless-steel frame for a high energy electron accelerator operating at an incident electron energy of 7.5 MeV. Optimization of the x-ray spectra of the converter is investigated in this paper by adding a beam hardening filter from copper, aluminum, and stainless steel. The MCNP code is used to simulate the particle transport through the converter design. To survey the effect of each filtered spectra, angular dose distribution in the air is measured at radial distances of 50, 75, and 100 cm from the tantalum for the angle of 0° to 90°. A comparison between the unfiltered and the filtered spectra shows a marked decrease in low energy photon intensity up to the energy of 100 keV by all three filter materials with a greater reduction and hardening when combining the filter materials. These findings result in the angular dose distribution of the produced x-ray having a lower intensity at closer radial distances to the target due to the decreased intensity of x-rays with low energy, denoting a better dose homogeneity over the irradiated material.

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