Cent Percent Negative Joshi Effect in a Gas Phototube beyond a Threshold Photoemission

Abstract

In order to confirm Joshi’s postulate that the photoelectric emission in the discharge space is a necessary primary stage in affecting the discharge current, the present study of the photo-diminution of the discharge current pulses for external electrode excitation by 60 c/s A.C. of a gas-filled phototube was undertaken specially to see whether Joshi effect was absent with the light of the frequency lower than the threshold value required for the photoemission. Besides the confirmation of the absence of the effect below the threshold frequency, the study reveals the necessity of a threshold photoemission for observing complete suppression of the discharge pulses.