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Projects / Programmes source: ARIS

INVESTIGATIONS OF METHOD FOR DETERMINING SMALL QUANTITIES OF INERT GASES RELEASED DURING OPERATION OF NONEVAPORABLE GETTERS (NEGs) IN ULTRAHIGH VACUUM (UHV) AND EXTREME HIGH VACUUM (XHV)

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Research activity

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 
T110  Technological sciences  Instrumentation technology 
T150  Technological sciences  Material technology 
T210  Technological sciences  Mechanical engineering, hydraulics, vacuum technology, vibration and acoustic engineering 
T450  Technological sciences  Metal technology, metallurgy, metal products 
Keywords
Non-evaporable getters, getter pumping speed, sorption capacity, spinning rotor gauge, zero signal stability, rate of pressure rise method, quadrupole mass spectrometer, calibration in dynamic mode
Evaluation (rules)
source: COBISS
Evaluation of bibliographic research performance indicators according to ARIS methodology
Citations Citations for bibliographic records in COBIB.SI that are linked to records in citation databases
source: WoS source: Scopus source: COBISS
Researchers (6)
no. Code Name and surname Research area Role Period No. of publications
1.  05673  PhD Bojan Erjavec  Electronic components and technologies  Researcher  2008 - 2011  136 
2.  09846  PhD Lidija Irmančnik-Belič  Chemistry  Researcher  2008 - 2011  99 
3.  21772  PhD Milorad Milun  Materials science and technology  Researcher  2008 - 2011  68 
4.  17830  Janez Osredkar    Technical associate  2008 - 2011  0 
5.  04254  PhD Janez Šetina  Electronic components and technologies  Head  2008 - 2011  251 
6.  25498  PhD Barbara Šetina Batič  Materials science and technology  Researcher  2008 - 2011  242 
Organisations (1)
no. Code Research organisation City Registration number No. of publications
1.  0206  Institute of Metals and Technology  Ljubljana  5051622000  6,009 
Abstract
Project is based on investigations and set-up of a method for quantitative determining small quantities of inert gases (in the range between 5 x 10-10 m3Pa and 10-7 m3Pa), which are generated during the operation of non-evaporable getters (NEGs) in UHV and EXV. Monitoring the accumulation of inert gases (noble gases and CH4) takes place in a closed vacuum chamber with a known volume by measuring total pressure while using a spinning rotor gauge (SRG). Measurements in static mode are enabled by an inert vacuum gauge. SRG is recognized as a precise (measurement uncertainty 0.5%) and stable (< 1% / year) reference standard in the range between 10-4 Pa and 1 Pa. SRG lowest limit, which can be extended down to 10-6 Pa, is determined by time stability of rotor residual drag (zero signal). Frequency dependence of residual drag has to be checked and considered. Quantitative determination of the composition of accumulated gases in a continuously pumped vacuum system takes place, after opening the valve separating the test chamber from the vacuum system, by measuring partial pressures using a residual gas analyser (RGA). Measurements in a dynamic mode hinder the influence of interaction of residual gases with a hot cathode of RGA on their actual composition. Due to RGA operation in dynamic mode and its short-term stability, a regular calibration with known quantities of selected gases has to be performed. Measurement set-up and method execution is based on: a) Extremely vacuum tight stainless steel (SS) chamber including valves, electrical feedthroughs and other components, in order to hinder the accumulation of atmospheric Ar, b) Maintaining constant ambient temperature and hindering mechanical shocks and vibrations for optimum SRG operation, c) NEG activation performed at low H2 and CO2 content in the residual atmosphere, d) Constant source of pure H2 evolving from inner SS vacuum chamber walls or additionally inserted SS sheets.
Significance for science
Studying a new method for determining small gas quantities and their composition, due to the outgassing of different electronic components and materials, is important for the research in of vacuum science and development of vacuum technology. Originality of the new method exists in: a) monitoring inert gas generation and accumulation during NEG hydrogen sorption at RT, and gas release during mechanical stirring of liquid In solders as well as during UV scrubbing of electron multipliers (EMs) at RT by measuring the increase of total pressure in static mode, using SRG as an inert, precise, high-resolution and long-term stable vacuum gauge, and b) analysing composition of accumulated gases by measuring partial pressures in dynamic mode, using QMS calibrated with known quantities of selected gases. Applicability of the new method reflects in offering the important additional quality control regarding outgassing properties of NEGs, In solder rings as well as EMs. Electronic components and materials with improved quality, incorporated in miniature vacuum photoelectron devices, enable the manufacture of high performance CPMs operating in both DC mode and photon counting mode. The new method can be adapted and used for determining small quantities of all gases releasing during stirring of liquid In solders and UV scrubbing. For the electron scrubbing phase, dynamic measurements are foreseen only in order to enable distinguishing between the gases released from EMs and the residual gases due to interaction with a hot cathode of incorporated electron gun. A contribution to the development of science is also the characterisation of new materials for vacuum optoelectronics based on intermetallic compounds of chemically active alkali and alkali-earth metals Li, Na, K, Cs, Ba and Ca with Ga, In or Sn, and studies of vacuum problems and lifetime of hermetically sealed vacuum devices like optoelectron tubes (vacuum tightness of glass-to-metal seals, permeation of helium through different glasses). A novelty appearing during the course of this project is the increased use nano-structured thin-film NEGs including their characterization, which is very important for prolongin the operational lifetime of MEMS.
Significance for the country
In many modern industrial processes (microelectronics and semiconductor fabrication, nanotechnologies, surface engineering, pharmaceutical industry etc) and in numerous research fields, the vacuum environment is an indispensable prerequisite (electron microscopy and other vacuum analytical methods, surface science, particle accelerators and synchrotron light sources, space research etc). A good understanding of relevant vacuum issues is crucial for new developments in these fields as well as in industrial development of new and better products. Our work can contribute to the fact that Slovenia keeps the contact with technological development in the world. The project group is very active in development and research related to new materials for opto-electronic components, i.e. special photomultipliers and MEMS. We are specialized in research of getter materials that have a decisive effect on a operational lifetime of miniature vacuum sealed devices. The group established cooperation with several foreign partners and through this cooperation we have achieved better visibility and recognition of our research capabilities. This can enable increased participation of Slovenian scientists in the research projects of 7th EU framework program as well as other EU projects.
Most important scientific results Annual report 2008, 2009, final report, complete report on dLib.si
Most important socioeconomically and culturally relevant results Annual report 2008, 2009, final report, complete report on dLib.si
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