Record Details
Spectral time-resolution of light from microwave discharges in helium
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | Spectral time-resolution of light from microwave discharges in helium |
| Names |
Tynes, Arthur Richard
(creator) Brady, James J. (advisor) |
| Date Issued | 1963-08-07 (iso8601) |
| Note | Graduation date: 1964 |
| Abstract | Temporal variations in individual spectrum lines emitted by a microwave discharge in pure helium are investigated: The discharge is produced in a quartz tube located inside of a section of waveguide which carries pulsed 3 centimeter microwaves. The helium used is purified by a three-fold process consisting of treatment with an activated uranium getter, diffusion through a quartz tube, and finally by cataphoresis. The impurities are estimated to be less than one part in 10⁹ and are possibly as low as one pert in 10¹⁰ In order to explain the temporal variations of the individual spectrum lines a theory to fit both an ideal three-level atom and an ideal six-level atom is developed. Both theories lead to a set of simultaneous differential rate equations which describe the temporal variations of the important variables including the light intensity of selected spectrum lines. Computer solutions of both sets of equations agree favorably with the experimental results. In this respect the eight rate equations which result from the six-level atom are in excellent qualitative agreement and moderately good quantitative agreement with the results of the experiment. The rate equations lead to a consistent and logical description of the plasma characteristics both during the microwave power pulse and during the afterglow which follows. It is shown that the process He[superscript m] + He[superscript m] -> He₂⁺ + e + KE is very important for producing the afterglow light spike and the rate equations are solved in an attempt to determine the conversion frequency for this process. This conversion frequency is estimated to be approximately 5 X 10⁻¹⁴m³/second although the rate equations are somewhat insensitive to changes in this parameter. The companion process to the above one, namely He[superscript m] + He⁺ -> He[superscript m] + He + e + KE is shown to be relatively unimportant as is the process He⁺ + 2He -> He⁺₂ + He. |
| Genre | Thesis/Dissertation |
| Topic | Electric discharges through gases |
| Identifier | http://hdl.handle.net/1957/48448 |
