Measurements of very small plasma concentration by RF resonator with periodic slow wave structure

• Date: 2003
• Main Authors: Ivanov, B.I., Prishchepov, V.P.
• Format: Article
• Language: English
• Published: Національний науковий центр «Харківський фізико-технічний інститут» НАН України 2003
• Series: Вопросы атомной науки и техники
• Subjects: Plasma diagnostics
• Online Access: http://dspace.nbuv.gov.ua/handle/123456789/110609
• Journal Title: Digital Library of Periodicals of National Academy of Sciences of Ukraine
• Cite this: Measurements of very small plasma concentration by RF resonator with periodic slow wave structure / B.I. Ivanov, V.P. Prishchepov // Вопросы атомной науки и техники. — 2003. — № 1. — С. 163-164. — Бібліогр.: 6 назв. — англ.

Necessity of contactless measuring small electron concentrations is actual, for example, in cosmic explorations, beam physics, electronics, etc. We found experimentally that the RF resonator with special periodic slow wave structure can measure n~10⁵-10⁸ cm⁻³. The frequency of the resonator main mode is 628 MHz; Q=4500, phase velocity is 4.4·10⁹ cm/sec. To determine the form-factor for this mode, an electron beam was passed through the resonator along its axis in vacuum of order of 10⁻⁶ Torr. The beam parameters were as following: energy 100 eV, current 1-10 mA, diameter 1 cm, that is corresponds to n~10⁷-10⁸ cm⁻³. Measurement accuracy was about of 10 %. After the calibration, this resonator was used successfully for plasma density measurements that created by proton beam with energy 5 MeV at ionization of gases at pressure of 10⁻⁴-10⁻⁵Torr.