GENERATION OF NEGATIVE IONS IN A GAS DISCHARGE. RCA Victor Research Report No. 7-811-6
The generation of heavy negative ions in a gas discharge was investigated. The negative ions were generated by producing a discharge through mixtures of electronegative gases (SF/sub 6/ and I) and argon. Measurements of total ion currents showed that negative ion current densities of 0.4 mamp/cm were obtained in the SF/sub 6/-Ar ion source and 0.24 mamp/cm/sup 2/ in the Ar--I discharge. Mass spectrometer measurements indicated that SF/sub 6/ is highly dissociated in the ion source and as a result it was found that the atomic fluorine (F/sup -/) is the predominant ion in the ion beam extracted from the gas discharge. For the Ar--I gas discharge the ion beam was essentially that of atomic iodine (I/sup -/). Langmuir probe measurements in the gas discharge ion source showed that in both types of gas mixture the negative ions are the most abundant charge carriers in the plasma. In SF/sub 6/--Ar mixtures the negative ion concentration is estimated at 99.8%, while for the Ar--I mixture the estimate of the negative ion concentration is 98%. The results indicate that an ion source could be designed to produce negative ion beams with an intensity of an order of magnitude higher than those achieved. (auth)
- Research Organization:
- RCA Victor Co., Ltd. Research Labs., Montreal
- NSA Number:
- NSA-18-006299
- OSTI ID:
- 4122270
- Report Number(s):
- ASD-TDR-63-858
- Country of Publication:
- United States
- Language:
- English
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