Stability of bakeable capacitance diaphragm gauges

TL;DR

This paper investigates how baking affects the stability and accuracy of capacitance diaphragm gauges, finding that baking causes zero offset shifts but minimal linearity changes, with overall uncertainties remaining below 0.3%.

Contribution

It provides an analysis of the stability of capacitance diaphragm gauges before and after baking, highlighting the importance of understanding linearity effects for accurate measurements.

Findings

Baking causes zero offset shifts in gauges.

Linearity cannot be corrected at use, affecting measurement accuracy.

Total uncertainty remains below 0.3% after baking.

Abstract

Here, we study the stability of capacitance diaphragm gauges. We focus on their stability before and after a controlled series of bakes. We find that baking results in appreciable shifts of the zero offset, but note that these can easily be corrected at time of use. Linearity however cannor be corrected at time of use, so it is essential to understand its effect if one wished to use similar gauges in a system that requires baking. For the gauges in this study, we find that baking introduces a minimal additional uncertainty, and that the total uncertainty can be kept to below about 0.3% at the k=2 confidence level (95%).