A microwave interferometer for small and tenuous plasma density measurements

Journal Article · Fri Mar 15 00:00:00 EDT 2013 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.4797470· OSTI ID:22105455

Tudisco, O.; Falcetta, C.; De Angelis, R.; Florean, M.; Neri, C.; Mazzotta, C.; Pollastrone, F.; Rocchi, G.; Tuccillo, A. A. ^[1]; Lucca Fabris, A.; Manente, M.; Ferri, F.; Tasinato, L.; Trezzolani, F. ^[2]; Accatino, L. ^[3]; Pavarin, D. ^[4]; Selmo, A. ^[5]

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1. ENEA CR Frascati, Via E. Fermi 45, 00044 Frascati (Italy)
2. CISAS 'G.Colombo,' Universita degli studi di Padova, Via Venezia 15, 35131 Padova (Italy)
3. ACC Antenna and MW tech, Via Trieste 16/B, 10098 Rivoli (Italy)
4. Dip. di Ingegneria Industriale (DII), Universita degli Studi di Padova, Via Venezia 1, 35131 Padova (Italy)
5. RESIA, Studio Progettazione e Realizzazione di Apparati Elettronici, via Roma 17, 37041 Albaredo d'Adige (Italy)

The non-intrusive density measurement of the thin plasma produced by a mini-helicon space thruster (HPH.com project) is a challenge, due to the broad density range (between 10{sup 16} m{sup -3} and 10{sup 19} m{sup -3}) and the small size of the plasma source (2 cm of diameter). A microwave interferometer has been developed for this purpose. Due to the small size of plasma, the probing beam wavelength must be small ({lambda}= 4 mm), thus a very high sensitivity interferometer is required in order to observe the lower density values. A low noise digital phase detector with a phase noise of 0.02 Degree-Sign has been used, corresponding to a density of 0.5 Multiplication-Sign 10{sup 16} m{sup -3}.

• OSTI ID: 22105455
• Journal Information: Review of Scientific Instruments, Vol. 84, Issue 3; Other Information: (c) 2013 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0034-6748
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
DENSITY
INTERFEROMETERS
MICROWAVE RADIATION
PLASMA
PLASMA DENSITY
PLASMA DIAGNOSTICS