A Catalytic Sensor for Measurement of Radical Density in CO2 Plasmas

Sensors

Alenka Vesel¹  Rok Zaplotnik¹  Jonathan Iacono²  Marianne Balat-Pichelin² 

[1] Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia; E-Mails:;PROMES-CNRS Laboratory, 7 rue du Four Solaire, 66120 Font-Romeu Odeillo, France; E-Mails:

关键词: catalytic probe;    plasma probes;    atom measurement;    dissociation fraction measurement;    carbon dioxide plasma;   

DOI  :  10.3390/s121216168

来源: mdpi

【 摘 要 】

A catalytic sensor for the measurement of radical density in weakly ionized CO₂ plasmas, created in a low-pressure electrodeless discharge, is presented. The CO₂ plasma was created in a 4 cm wide borosilicate glass tube inside a copper coil connected to a radio frequency generator operating at 27.12 MHz with a nominal power of 250 W. The dissociation fraction of the CO₂ molecules was measured in the early afterglow at pressures ranging from 10 Pa to 100 Pa, and at distances of up to 35 cm along the gas stream from the glowing plasma. The radical density peaked (2 × 10²⁰ m⁻³) at 80 Pa. The density quickly decreased with increasing distance from the glowing plasma despite a rather large drift velocity. The dissociation fraction showed similar behavior, except that the maximum was obtained at somewhat lower pressure. The results were explained by rather intense surface recombination of radicals.

【 授权许可】

CC BY   
© 2012 by the authors; licensee MDPI, Basel, Switzerland