Development of a Laser Induced Fluorescence (LIF) system on the Plasma Material Interaction System (PLAMIS-II) device

Abstract

A laser induced fluorescence (LIF) system has been developed for the plasma material interaction system (PLAMIS-II) device, which is equipped with a unique plasma gun composed of a LaB6 cathode and two anodes with electromagnets to generate a focused dense plasma. PLAMIS-II simulates the interactions of plasma with different materials and is to be used for the test of plasma facing components of fusion devices. The LIF system is composed of a seed laser with Littmann/Metcalf cavity and a master oscillator power amplifier to pump 3d(4)F(7/2) metastable argon ion to 4p(4)D(5/2) level at the wavelength of 668.61 nm, which has the following input parameters: laser power = 20mW, line width ˂ 100 kHz, and a mode-hop free tuning range ˃ 70 GHz. For in-situ measurement of laser wavelength, the wavelength spectrum of an iodine cell was measured by a photo-transistor during LIF measurement. To measure argon ion temperature (T-i) and drift velocity (v(d)) in PLAMIS-II, the fluorescence light with the wavelength of 442.72 nm, emitted from 4p(4)D(5/2) level to 4s(4)P(3/2) level and passing through 1 nm band-width filter, was collected by the photomultiplier tube combined with a lock-in amplifier and a chopper with frequency of 3 kHz. Initial data of T-i and v(d) were analysed in terms of gas flow rate and applied power.