Projects / Programmes
Creation and maintenance of ultrahigh to extremely high vacuum
Code |
Science |
Field |
Subfield |
2.09.00 |
Engineering sciences and technologies |
Electronic components and technologies |
|
Code |
Science |
Field |
P180 |
Natural sciences and mathematics |
Metrology, physical instrumentation |
P351 |
Natural sciences and mathematics |
Structure chemistry |
P352 |
Natural sciences and mathematics |
Surface and boundary layery chemistry |
T151 |
Technological sciences |
Optical materials |
T210 |
Technological sciences |
Mechanical engineering, hydraulics, vacuum technology, vibration and acoustic engineering |
Hydrogen outgassing, hydrogen recombination, ultra-fine leaks, helium permeation, rate of pressure rise method, spinning rotor gauge, recombination coefficient
Researchers (13)
Organisations (1)
Abstract
We will study the most critical problems in achieving ultrahigh to extremely high vacuum in large dynamic vacuum systems, such as hydrogen outgassing in austenitic stainless steel vacuum vessels, and in maintaining of ultrahigh to extremely high vacuum in miniature static vacuum systems (special photoelectron tubes), such as ultra-fine leaks through indium soldered seals and helium permeation through quartz input windows. Hydrogen outgassing rate in small-volume test cells with internal surfaces, preconditioned at well-defined conditions, will be measured at room temperature using a very accurate method, based on the rate of pressure rise method, applying the spinning rotor range. The obtained results will be used for modelling the process of hydrogen evolution, considering hydrogen diffusion from bulk to the surface and hydrogen recombination on the surface. The model will be used to determine recombination coefficient, characteristic for a given surface. Varying the surrounding temperature in a narrow range, an activation energy for the process of hydrogen evolution will be determined. Ultra-fine leaks, leading to atmospheric argon accumulation, will be tested at room temperature in test samples using the rate of pressure rise method. The indium solder surfaces will be analysed using a highly sensitive Auger Electron Spectroscopy and X-ray Photoelectron Spectroscopy. Helium permeation flow rate in dependence on time through quartz faceplates, leading to atmospheric helium accumulation, will be measured using a helium leak detector. Accurately determined permeation and diffusion constants at room temperature will be used for modelling a time dependency of helium flow at a sudden change of helium surrounding pressure. We will be able to foreseen the rate of helium pressure rise in photoelectron tubes. The rate of helium pressure rise will be measured additionally in test samples at room temperature using the rate of pressure rise method.