AIG1xG Ion Gauges
From £285.00 excl. VAT and transportation costs
Nude Bayard-Alpert ion gauges covering the vacuum range 1x10-3 to 3x10-11 mbar.
- Range 1x10-3 to 3x10-11 mbar
- Twin tungsten, thoria or yttria-coated filaments available
- Degassing by electron-bombardment
- Bakeout temperature 250ºC
- DN40 CF mounting flange
|Order Code||Description||Price £|
|AIG17G||UHV BA Ion Gauge, Tungsten Filaments||285.00|
|AIG18G||UHV BA Ion Gauge, Thoria Coated Iridium Filaments||325.00|
|AIG19G||UHV BA Ion Gauge, Yttria Coated Iridium Filaments||325.00|
|FIL17||Replacement Twin Tungsten filament assembly||30.00|
|FIL18||Replacement Twin Thoria-coated iridium filament assembly||60.00|
|FIL19||Replacement Twin Yttria-coated iridium filament assembly||60.00|
Filament type selection is a complex subject largely dependent on the vacuum environment they will be used in. A basic description follows but does not cover all situations.
Tungsten filaments. These are widely used because they are relatively inexpensive. They operate hotter than other types so will evaporate contamination from the filament surface resulting in a more stable gauge operation. However, this advantage may increase outgassing from surrounding surfaces due to elevated temperatures. Tungsten is not affected by Hydrocarbons and Halogens so is the filament to use if these are present. Tungsten filaments are very fragile and will not survive exposure to air or mechanical mishandling.
Thoria-coated iridium filaments. These operate at a relatively cool temperature (1400deg.C) resulting in reduced outgassing and chemical reactivity with other gasses. They are considered the filament of choice when operating in the ultrahigh vacuum region. Iridium does not burn out if exposed for a short time to high pressures while hot and so can survive a sudden loss of vacuum without damage.
Yttria-coated iridium filaments. Exposure to the alpha particles emitted by thorium is of concern to some users. Yttria-coated filaments share very similar thermionic characteristics and behave the same as thoria-coated filaments but without the particle emission.