Aluminum's Extreme Vacuum Performance Potential
The Atlas Aluminum Revolution
The Atlas Aluminum Revolution...
aluminum’s machinability; reduced outgassing
volume and surface area; fast cycling, bakeout
and pump-down times; reduced footprint and
smaller/lighter support structures; reduced
shipping cost; and lower disposal costs when
dealing with nuclear activation applications.
Any single physical or chemical property of
aluminum may be enough reason to select
aluminum as a vacuum chamber choice over
stainless steel. But when looked at in summary, aluminum overwhelmingly surpasses
stainless steel as providing the lowest cost of
ownership.
Aluminum’s properties, when looked at in sum, offer
many compelling physical and cost of ownership advantages over stainless steel.
Why choose Aluminum?
• Low Outgassing
• Low Contamination
• High Thermal Conductivity
• High Vibration Dampening
• Superb Machinability
• Space and Weight Reduction
• Low Nuclear Activation
• Low Magnetic Permeability
• High Chemical Resistance
• Low Cost of Ownership
Chen, J.R. et al. Thermal Outgassing from Aluminum
Alloy Vacuum Chambers. Journal of Vacuum Science
and Technology A 3. p. 2188.
(1)
(2)
O’Hanlon, John. Ultrahigh Vacuum in the Semiconductor Industry, Journal of Vacuum Science and
Technology A 12, p. 921.
4 Atlas Technologies
Aluminum has seven orders of magnitude
less hydrogen than stainless steel. It has very
low levels of Carbon, resulting in significantly
less H2O, CO, C2 and Ch4 than stainless steel.
Aluminum vacuum systems require far less
pumping than comparably equipped stainless
steel chambers. A baked aluminum chamber
has an outgassing rate of less than 1x10–13
Torr liter/sec cm2 compared to Stainless' 6.3
x10–11 Torr liter/sec cm2 (1).
With low nuclear activation, aluminum has a
short neutron activated half-life measured on
a scale of hours—significant when compared
to stainless steel’s scale, which is measured
in thousands of years. This offers huge
disposal savings and a priceless reduction in
potential exposure to staff.
Aluminum is essentially magnetically transparent (non-magnetic). An aluminum UHV
chamber’s low magnetic permeability offers
no measurable disruption to electron and ion
optics.
With a low Young’s’ modulus (69GPa) of
elasticity (1/3 that of stainless steel, 207GPa)
aluminum offers outstanding vibration
dampening, making it the material of choice
for precision synchrotron, semiconductor and
physics applications where excess vibration
can have disastrous consequences.
An aluminum chamber processed according to Atlas specification AVSP-08, entails
cleaning and baking surfaces to facilitate the
formation of a dense oxide passivation layer
through the conversion of hydroxides into
stable oxide molecules. The resulting surface
inhibits the diffusion of other