Test of collinear spectroscopy for precise high-voltage determination

Abstract

Collinear spectroscopy holds promise for a precise determination of high dc voltages with an accuracy in the order of 10−6. For this purpose the velocity of ions, which are accelerated with the voltage to be measured, is determined by the analysis of the Doppler effect of their optical resonances. This article describes the construction and test of a prototype designed for measuring voltages from −20 up to −50 kV in collinear spectroscopy. In this way the feasibility of the method, its limitations, and the sources of uncertainty have been investigated experimentally. Thereby the frequencies of the two 3d 2D3/2,5/2→4p 2P3/2 transitions of Ca II have been measured with high accuracy.