Accession Number:

AD0296396

Title:

ION GAUGE CHARACTERISTICS IN AN AEROSPACE SIMULATOR

Descriptive Note:

Corporate Author:

ARNOLD ENGINEERING DEVELOPMENT CENTER ARNOLD AFS TN

Report Date:

1963-02-01

Pagination or Media Count:

61.0

Abstract:

An investigation was made to determine the relationship of ion gauge readings to the fundamental gas properties of pressure, density, and molecular incidence rate, and to study a modification of the ion gauge for use in space simulators where directional pressures exist because of large cryogenically- cooled pumping areas. A theoretical analysis of the operation of the ion gauge suggested that a nude gauge senses the density of gas in a vacuum chamber, whereas a tubulated gauge senses the amount of molecular flux incident on the mouth of the tubulation neither gauge actually measures pressure. Experiments were then conducted with specially constructed gauges in a vacuum system where the gas parameters could be varied individually to check the validity of the analysis. The predicted behavior was obtained with both nitrogen and helium, although some anomalous results were seen in the latter case. The modified ion gauge, also known as the Space Simulation Gauge, is a tubulated gauge incorporating a cryogenic pumping surface to reduce the response to the incident flux of condensible molecules as if the flux were reflected from the wall of the space chamber having cryogenic pumping panels. A means of calculating the proper pumping area within the gauge was developed and applied. The ability to produce the intended reduction in sensitivity was experimentally confirmed, and some effects of gauge geometry were explored.

Subject Categories:

  • Test Facilities, Equipment and Methods

Distribution Statement:

APPROVED FOR PUBLIC RELEASE