Theoretical Calculation of the Number of ^|^alpha;-ray Track in a Petri Dish-type Cloud Chamber with Monazite Source

• Published in: Radioisotopes Vol. 61; no. 8; pp. 399 - 406
• Main Authors: MORI, Chizuo, HAYAKAWA, Issei, SAGOU, Yutaka
• Format: Journal Article
• Language: English; Japanese
• Published: 2012
• ISSN: 0033-8303; 1884-4111
• DOI: 10.3769/radioisotopes.61.399

In the case of petri dish-type cloud chamber with an alpha-ray source of monazite sphere(2.5mm diameter), the expected number of the alpha-ray tracks was theoretically calculated using Bethe formula and compared with the reported experimental value. The validity of the calculation method was firstly confirmed. The theoretically calculated number of alpha-ray tracks(0.208 per second) in a cloud chamber was fairly agreed with experimental value(0.383 per second). During the observation of the tracks, the surface of the source was gradually wet with ethanol-liquid. The thickness of the liquid layer was estimated to be 6 mu m by comparing the calculated escape probability of the alpha-rays and the experimental value under having the liquid layer on the source surface.