Determination of Cr density during high-current anode modes in vacuum arc

Abstract

The results of Cr density during high-current anode modes using broadband absorption spectroscopy are presented. The vapor density of atomic Cr is determined during the formation of anode spot type 1, anode spot type 2, and anode plume. Cr I resonance lines at 425.43 nm are used for the analysis. An AC current pulse with a maximum of about 7 kA and a frequency of 100 Hz is applied. By adjusting the opening time or contact opening speed, anode spot type 1 and type 2 may appear. The temporal evolution of the ground state density of Cr atoms shows about two times higher metal vapor during anode spot type 2 compared with anode spot type 1. The vapor density during an anode plume following anode spot type 2 is also determined and is compared with the same time instant in which no anode plume appears, i.e., only when anode spot type 1 appears.