Preliminary gas desorption studies from tungsten exposed to He plasma in GyM linear device using Laser Induced Desorption Spectroscopy

Laser Induced Desorption Spectroscopy (LIDS) has been used to investigate the helium desorption from coatings and bulk tungsten in laboratory experiments as a prerequisite for the later application in-situ in the GyM linear device. Tungsten coatings were deposited on a silicon substrate by magnetron sputtering process. After a preliminary surface characterization and before studying the gas desorption by LIDS, both types of tungsten samples were exposed to helium plasma in the GyM linear device. A Nd:YAG laser with constant output power leading to a smooth controllable increase of layer temperature was used, resulting in a complete desorption of gases in a point heated by the laser. The desorbed gases were detected up to 200 amu/e with a QMS (Quadrupole Mass Spectrometer). The results of the application of LIDS on tungsten targets exposed to a wide range of helium fluxes, fluences, and impact energies under different surface temperatures are presented and compared with Thermal Desorption Spectrometry (TDS) and Laser Induced Breakdown Spectroscopy (LIBS).