Record Details
Field | Value |
---|---|
Title | Experimental determinations of electron energy distributions for Townsend discharges in helium gas |
Names |
Roberts, Thomas David
(creator) Burch, David S. (advisor) |
Date Issued | 1965-04-07 (iso8601) |
Note | Graduation date: 1965 |
Abstract | The energy distribution of electrons in Townsend discharges in helium has been experimentally investigated in a direct fashion. A discharge is initiated between parallel plates of a small cell mounted at the center of a spherical retarding field energy analyzer. The anode of the cell is perforated and some electrons from the discharge enter the retarding field region. Pressures in the discharge cell are of the order of 1 torr and the pressure in the analyzer region is about 10⁻⁷ torr, so no significant alteration of the electron energy spectrum due to collisions takes place after electrons have left the discharge cell. The electron current reaching the collecting surface of the analyzer is measured as a function of retarding field strength. The usual perturbations due to probe measurements in the discharge itself are thus minimized. The interaction of electrons with the surfaces of the analyzer is considered, and the experimental data are corrected for the resulting electron reflection and secondary emission. A gold black analyzer surface exhibiting low total electron secondary emission coefficient is utilized. Experimental electron energy distributions are compared with the theoretical calculations of Heylen and Lewis, and qualitative agreement is found for helium. The correction due to electron reflection and secondary emission is shown to be minor. |
Genre | Thesis/Dissertation |
Topic | Electric discharges through gases |
Identifier | http://hdl.handle.net/1957/48098 |