Construction of a Bayard- Alpert type hot cathode ionization gauge

Date

3-1991

Degree

Bachelor of Science in Agriculture

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Feliciano T. Bantilan Jr.

Abstract

A hot-cathode ionization gauge was constructed using the Bayard-Alpert type architecture. The filament and the collector was constructed of 0.25 mm diameter-99.99% pure tungsten wire, the grid of 0.50 mm diameter-99.99% pure molybdenum wire, and the supports of Pyrex glass tubes and rods. The effective length of the gauge was made 40.00 mm, the diameter of the grid-helix, 22.00 mm with a wire spacing of 1.50 mm, and the filament-grid spacing, 2.00 mm. The gauge was tested but not characterized for its sensitivity. In all tests, the collector current and the ratio of the collector current to the grid current decreased exponentially with respect to time. This result indicates that the gauge is working according to expectations. At the same time the effects of varying the different control parameters of the hot-cathode ionization gauge were investigated. A change in the grid voltage leads to a positive and linear change in the grid current, and more importantly a positive, non-linear change in the collector current which demonstrates the grid-voltage's control over the ionization efficiency of the electrons. A change in the filament-supply voltage leads to a positive, non-linear change in grid current which demonstrates the former's control over the thermionic emission current density. A change in the collector voltage leads to a positive, non-linear change in the collector current. This demonstrates the former's control over collecting efficiency of positive ions.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

Thesis

Document Type

Thesis

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