Probing air pressure in the measurement of stopping powers of the alpha
particles in a very small-size detection system

Detection of alpha particles using small detectors in compact system play a vital role in radiation monitoring. This paper aims to examine the stopping power of α- particles emitted by ²⁴¹Am source via varying air pressure and distances. In the present work, the energy losses of the α-particles are measured at various distances ranging from 1.5 cm to 2.3 cm in steps of 2 mm. Further, the air pressure inside the chamber varied from 10 to 100 kPa. The size of the chamber was very small approx. ½ l in volume. The observations of energy losses were performed using a Si detector, deposited on a PIN photodiode. The dimensions of the detector are 10mm×10mm and 5mm thickness. It has been observed, the stopping power increases with the increasing air pressure inside the chamber. However, the number of α-particles reaching the detecting unit showed decreasing behaviour when the distances were increased, errors due to randomness are considered and incorporated in the analysis. The peak analysis is done with the Gaussian function using the software ORIGIN. The measurements are compared with the SRIM and ASTAR, the measured values are good in agreement with both codes.