PP2000/PP2000T SEM Dewar and Cold Stage
The PP2000 / PP2000T cold stage attaches to the SEM stage introducing a cold block for low temperature observation. Cooling of the stage is by pre-cooled nitrogen gas. An important and unique feature of the PP2000T / PP2000 SEM dewar system is the fact that the SEM stage and anti-contaminator (cold trap) are cooled by two separate cold gas circuits. This configuration means that the user can easily set up a large temperature difference between the SEM stage and the anti-contaminator - typically in the region of 50oC – without compromising the stability of the SEM stage.
SEM cooling Dewar.
 PP2000 / PP2000T cold stage located on SEM stage. Typically the anti-contaminator is mounted above the SEM stage (very close to the SEM polepiece) |
 SEM stage and anti-contaminator system (mounted on UHV flange for testing). Separate cooling of the anti-contaminator plate and SEM stage allows a large temperature difference to be maintained without compromising the stability of the SEM stage. Note the position of the anti-contaminator is adjustable using jigging (top). |
NEW OPTION - off-column SEM cooling dewar
- Replaces column mounted cooling dewar
- Seven hours plus between filling
- Superb stability
- Conveniently floor mounted (behind SEM)
Key Features
- Welded stainless steel Dewar (on-column) - the dewar is constructed from welded stainless-steel using UHV manufacturing techniques. There are no "O" rings that can cause leaks and no materials that can oxidise.
- Cold stage - a unique stage clamping mechanism ensures easy sample interchange and intimate thermal contact. A ceramic plate ensures an effective thermal break between the standard SEM stage and the cold cryo stage.
- Rapid cooling - the stage can be cooled to operating temperature in five minutes
- Temperature monitoring and control - the stage can be cooled to a minimum of -190oC and heated to a maximum of +50oC and monitored and controlled at all times.
- Easy on / easy off - the cold stage can be simply and quickly detached from the SEM stage. When necessary the Dewar can also be removed using unique KF fittings especially designed for this purpose.
- Novel anti-contaminator design - the anti-contaminator shield is cooled independently of the SEM stage by circulating dry Nitrogen gas and is designed to run at a temperature of around -190oC. During installation the user can select the optimum location of the anti-contaminator within the SEM, for maximum efficiency this is generally as close to the sample as is practicable. A combination of flow metre and pressure regulator ensures optimal cooling at all times. A monitor in the control console displays the anti-contaminator temperature.
Special SEM dewar for low vacuum operation
The standard PP2000 / PP2000T SEM cooling dewar is actively pumped by the SEM pumping system. An optional variation is available that allows the PP2000 / PP2000T SEM cooling dewar to be vacuum isolated from the SEM during low vacuum operation. In "normal" high vacuum SEM mode the isolation valve can be opened to restore active pumping of the PP2000 / PP2000T SEM cooling dewar.
PP7450 self pressurising 30 litre liquid nitrogen dewar
The PP7450 will give an economical source of dry nitrogen gas for cooling the SEM stage and SEM anti-contaminator. 30 litres of liquid will give at least one weeks normal use.
PP7450 Pressurised dewar
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