Stopping Power of Alpha Particles in Helium Gas

Abstract

The stopping power and the range of alpha particles emitted from Am-241 source has been investigated in helium gas at different pressures of 0 to 1 bar, using surface barrier silicon detector in the large vacuum chamber. The energy loss has also been obtained at variable distances from 2 to 8 cm. It is observed that as the pressure in a large vacuum chamber increases, the energy loss of the alpha particle decreases. The measured energy loss of alpha particles at lower pressure of 0 bar is less, but at higher pressure of 1 bar is more. As expected from Bethe --- Bloch formula, the stopping power of charged particle in helium gas at different pressure was found to increase significantly when pressure is increased. The measured value of stopping power and range were compared with SRIM and theoretical value. The experimental value of stopping power and range was found to be very close to the SRIM and theoretical value. Then, the measured value of range was compared with experimental using the Bragg --- Kleeman's rule