Abstract
This paper is to investigate stopping power of α-particles in air at various pressure of 0 to 1 bar, using a surface barrier silicon detector. The energy loss has been obtained at a different distance from 0 to 10 cm. It was found that the energy of the passed α-particles has been decreased in a small vacuum chamber with increasing pressure. It is also studied that the amount of α-particles reaching the detector follows a decreasing behavior as the distance increases. The result of stopping power was compared with ICRU and SRIM result. Experimental, ICRU and SRIM results for stopping power are closely in good agreement.