GB/Z 42624-2023 Active National standards

GB/Z 42624-2023 Vacuum technology—Vacuum gauges—Procedures to measure and report outgassing rates

Publish Date: 2023-05-23 Implement Date: 2023-05-23 For services related to genuine standard inquiry, procurement, translation, and other related services in China, please Contact Us

Basic Information

Standard Code: GB/Z 42624-2023

Standard Type: National standards

Standard Status: Active

is_force_gb: no

CCS Name: Vacuum technology and equipment

ICS Name: Vacuum technology

Publish Date: 2023-05-23

Implement Date: 2023-05-23

Pages: 34 pages

Scope

This document specifies the test procedure for the outgassing rate of vacuum chambers and their components. The outgassing rate applicable to this document is generated by equipment used in high vacuum or ultra-high vacuum, and at 23 °C, it is less than 1×10-5 Pa·m3·s-1 (1×10-2 Pa·L·s-1). All gases or vapors generated by outgassing have a molecular weight of less than 300 u.
The upper limit of the total outgassing rate, 1×10-5 Pa·m3·s-1, is independent of the size, total surface area, material, or state of the outgassing material. If the nominal outgassing rate (outgassing rate per unit area) has been measured, the area used is the nominal geometric surface area rather than the specific surface area including surface roughness. When it is difficult to determine the nominal geometric surface area of samples (such as powders, porous materials, very rough surfaces, or complex equipment), the outgassing rate per unit mass (such as the outgassing rate per gram) is used instead.
In many practical applications, it is only necessary to determine the total outgassing rate. If test instruments with sensitivity related to gas types are used, the total outgassing rate is given in the form of an equivalent nitrogen outgassing rate. If the total outgassing rate is very high, in order to improve the sample material, there is a need to identify the types of interfering gases and determine their outgassing rates. This document covers both of these situations.
Some molecules generated by outgassing can be adsorbed on the surface and remain there for much longer than the total test time. These molecules cannot be detected by test instruments when they are not in the direct path. This can be considered a surface effect, and surface analysis studies are far more effective than the conventional outgassing rate measurements considered here. Similarly, molecules released from the surface under ultraviolet or X-ray irradiation are also not applicable to this document.