Pumping Stancam

Before pumping the Stancam dewar it is necessary to warm it up to room tempearture, you do this by turning off the Cryotiger cooler.

Turning Off the Cryotiger

Switchboard	Location of Cryotiger Fuse & Circuit Breaker

Open the door to the left of the two keys used to reset the safety system.

At the top centre hinden behind a yellow note are a fuse and circuit breaker for the Cryotiger. Put either of these down will cut the power to the Cryotiger.

You now have to wait typically at least 3 hours for the temperature of the Stancam CCD to rise above zero centegrade, you can monitor this from the WWW TMS plot TMS database and select '540 - Stancam Detector'.

Pumping

To connect the vacuum pump to stancam as shown below. Note because of the awkward position of the connector it can be a bit difficult to get the vacuum hose and valve aligned, persevere! Plug the vacuum pump in to a suitable electrical mains socket, it is probably best to use an extension cable from the dome cupboard and a wall socket. Check the pressure display is turned on.

Vacuum Connection to Stacam Dewar

Once the Stancam detector is above 0^oC, open to black multiturn valve on the pump, about seven turns. Then press the start/stop button and the pump should start. Wait until you see a vacuum of below E-2 on the display then open the Stancam valve, it is sprung load and you turn it only about half a turn until you see the word 'OPEN'.

Vacuum Pump	Vacuum Pump Pressure Display

Normally you will need to pump for at least 5 hours, but longer the better. Below is an example of a warmup and pumping sequence. Here it took about 5 hours for the detector to go above 0^o C, when you can start pumping. Also in the pumping plot it can be seen you should get below 0.0002 mbars within a hour.

Warmup and Pumping examples	Expanded Pumping Profile

Cooling and Stop Pumping

Assuming it is required to now cool Stancam go to the switchboard and lift up the Cryotiger circuit breaker and/or fuse that's down. Let the Cryotiger cool for a while or when the dewar pressure is the same or below the pump pressure, before disconnecting the pump. In the example plot above it took about 2 hours from switching on the Cryotiger until the detector reached its operating temperature of -95.1^o C.

To disconnect the pump:

1. Close the yellow valve on Stancam, half turn clockwise and you will see the word CLOSED.
2. Close the multiturn black valve on the pump, about seven turns.
3. Stop the pump by pressing the Stop/Start button, it takes the pump a few minutes to slow down to a stop.
4. Unclamp the vacuum tube from Stancam. Note because there will still be a vacuum in the tube the best way to release the tube after you've removed the clamp is to tilt it rather than trying to pull it off straight.
5. Disconnect the vacuum pump from the main and wheel it back to its home position next to the telescope.