The SEM and Ion Pumps

UHV Systems

UHV – Ultra High Vacuum

Pressures of less than 10^-11 mbar

Pumps at an “atomic level”

Ion Pump

Also known as a “sputter ion pump”

Ionizes and captures gas via high electric potentials

Several different breeds, with common components.

Penning Trap

Standard Diode Pump

Contains one anode cathode set.

Common cathode material is Ti.

Efficiency/speed based on several factors.

“Pumping Action”

Sputtered Ti atoms act as getters.

Chemisorption and physisorption.

Net decrease in targeted particles.

Triode Pump

Contains one anode and two cathodes.

Noble Diode Pump

Same design as a standard or triode pump.

Makes use of tantalum to capture rebounding neutrals.

Ideal for applications dealing with light inert gasses like He or H2

Cost and Lifetime

Cost varies greatly...

Lifetime inversely proportional to pressure.

Industry standard at 40k hours at 1.3X10^-6 mbar

Main Advantages

No moving parts.(In contrast to turbo molecular pumps, and diffusion pumps)

No vibrations.

Little maintenance, no “regeneration”