Open AccessThe rate of emission of γ -ray energy by radium B and radium C, and by thorium B and thorium C"
Author(s) -
L. H. Gray
Publication year - 1937
Publication title -
proceedings of the royal society of london. series a, mathematical and physical sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.814
H-Index - 135
eISSN - 2053-9169
pISSN - 0080-4630
DOI - 10.1098/rspa.1937.0071
Subject(s) - radium , thorium , ionization , volume (thermodynamics) , atomic physics , physics , point source , ion , homogeneous , electron , radiation , analytical chemistry (journal) , chemistry , uranium , nuclear physics , optics , chromatography , quantum mechanics , thermodynamics
Consider aγ -ray source situated in an infinite homogeneous medium. Ifqr , is theγ -ray energy absorbed per unit volume of the medium at a distancer from the source, the total energy emitted by the source isQ = 4π ∫∞ 0 qr r2 dr . (1) If a small air-filled cavity is introduced at any point in such a medium, the number of pairs of ions per unit volumen produced in the air in the cavity is related to theγ -ray energy absorbed per unit volume of the mediumqr by the equationqr =nWρ , (2) whereW is the average energy lost by the secondary electrons per ion pair formed in the air, andρ is the ratio of the rate of loss of energy by the secondary electrons in the medium and in air. Thus, in terms of the ionization per unit volumenr produced in a small air-filled cavity at a distancer from the source, equation (1) becomesQ = 4πWρ ∫∞ 0 nr r2 dr . (3) This paper describes a determination ofQ in this way for theγ -radiation accompanying the disintegration of Ra B and Ra C in equilibrium with radium, and for theγ -radiation emitted by Th B and Th C" in equilibrium with radio-thorium.