Letter | Published:

Saturation Characteristics of a Spherical Ionization Chamber and a Determination of Boag's Constant for Air

Nature volume 204, pages 670672 (14 November 1964) | Download Citation



Thomson and Rutherford's1 initial investigations of the saturation characteristics of a parallel plate ionization chamber were followed by theoretical treatments by Thomson2, Mie3, Seeliger4 and others. More recently, Boag and Wilson5 have shown by dimensional analysis that the collection efficiency, f (that is, the ratio of the measured current, i, to the ideal saturation current, is), is a function of d2q½V−1 where d is the distance between the plates, q is the rate of ionization and V is the applied voltage. Through the introduction of certain assumptions, they derived the following equation for the generalized saturation characteristic: k1 and K2 are the mobilities of the positive and negative ions respectively (that is, it is assumed that the current carried by electrons is negligible); α is the recombination coefficient; e is the charge per ion; m is Boag's constant.

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  1. Department of Mathematics and Physics, The Polytechnic, 309 Regent Street, London, W.1.

    • T. E. BURLIN
    •  & S. R. HUSAIN


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