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VACUUM TECHNOLOGY

VACUUM TECHNOLOGY 7.13

Permeation gas load is calculated in the same manner as the outgassing gas load.
Q = q × A
x x x
where Q = permeation load for material x, torr⋅1/s
x
q = permeation rate for material x, torr⋅1/s⋅cm 2
x
A = area of material gas is permeating through, cm 2
Leaks. Leaks are accounted for by measuring the leak rate by the rate of rise method or using a
helium mass spectrometer leak detector. It should be noted that if one measures the leak rate using
helium as a tracer gas, a conversion factor must be applied to relate that value to the leakage rate for
the higher molecular weight atmospheric gases nitrogen and oxygen.

7.7 FUTURE TRENDS AND CONCLUSIONS

Researchers are currently developing vacuum technology components (such as pumps, gauges, and
†
valves) using microelectromechanical systems (MEMS) technology. Miniature vacuum components
and systems will open the possibility for significant savings in energy costs and will open the doors
to advances in electronics, manufacturing, and semiconductor fabrication.
In conclusion, an understanding of the basic principles of vacuum technology, as presented in this
summary, is essential for the successful execution of all projects that involve vacuum technology.
Using the principles described in the chapter, a practitioner of vacuum technology can design a vac-
uum system that will achieve the project requirements.

FURTHER READING

Hoffman, D. M., B. Singh, and J. H. Thomas, Handbook of Vacuum Science and Technology, San Diego: Academic
Press, 1998.
Lafferty, J. M., Foundations of Vacuum Science and Technology, New York: Wiley, 1998.
O’Hanlon, J., A User’s Guide to Vacuum Technology, 2d ed., New York: Wiley, 1987.
Harris, N. S., Modern Vacuum Practice, 3d ed., London: BOC Edwards, 2004.

INFORMATION RESOURCES

The American Vacuum Society: www.avs.org
The Association of Vacuum Equipment Manufacturers International: www.avem.org
Safety on Vacuum and Pressure Systems: http://www.llnl.gov/es_and_h/esh-manual.html
American Society of Mechanical Engineers: http://www.asme.org/
The University of Alberta Vacuum: http://www.ee.ualberta.ca/~schmaus/vacf/
The Bell Jar: http://www.belljar.net/
International Vacuum Societies: http://www.sansalone.de/engl/LK_vacuum_associations.htm
Vacuum Industry Associations: http://www.sansalone.de/engl/LK_vacuum_industry_associations.htm
Journals of Vacuum Science and Technology: http://www.sansalone.de/engl/lk_vacuum_journals.htm
Physics on the Web: http://physicsweb.org/

† http://www.darpa.mil/mto/mems/index.html

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