Application of cavity theory to the discharge of electrostatic dust filters by x-rays

Abstract

Irradiation of electrostatic dust filters with x-rays can be used as a means to study the charged stage of these filters. The method requires knowledge of the rate of ion production in the filter interstitial cavities. Bragg-Gray cavity theory is used to determine the relationship between ion production in the cavities and that in free air as measured by the exposure. It is further shown that due to the cavity size found in actual filter systems that the generalized theory of Burlin is required for the proper estimation of this correction factor which depends on photon energy and filter type. An experimental method is proposed to check the validity of the calculations based on cavity theory and the results of experimental tests reported. Reasonable agreement is found between theoretical predictions and experimental results and the need for the use of an extended cavity theory clearly demonstrated.