In 2021, Indonesia planned to build high-energy accelerator electrons for the sterilization of medical instruments. With the transfer of technology from Russia to Indonesia like civil engineering, architecture, electrical, mechanical, control system, and instrumentation. But some several core technologies from accelerator electron like reviews for cavity material, strength of material cavity, vacuum system, electron accelerator system, and radiofrequency technology are not provided. For this reason, it is important to review one of the core technologies from the accelerator. This paper will review the material and strength of the material cavity of the accelerator with the software Finite Element Analysis (FEA) regarding the ILU-14 technology from Russia. Material cavity made from Oxygen free cooper with density 8,89 – 8,94 [g/cm3]. ILU-14 on the power of 100 KW can produce energy 7.5 MeV – 10 MeV. The accelerator consists of a 176 MHz acceleration structure based on a self-excited generator with a total of five GI-50A tubes. The diameter of the resonator is about 800mm with a length of 7875 – 9000 mm with a vacuum pressure of not more than 10−5 lTorr/s (0.133 x 10−2 lPa/s). The results based on the stress of the material will compare with the stress of the oxygen-free copper material.