The CCD temperature monitoring screen show text with white background. What can I do?

In the control room you can get this kind of information, The normal situation is to have only the text "OK" with a black background, text with white background means there is a problem.

"OK" means "Okay", the text "KO" means "KnockOut", and a rapid action must be taken.

In this example, Coralie has a serious problem ( Setpoint -115d, Current 19.9d), that means that Coralie ran out of nitrogen for hours and requires pumping before recooling.

Be aware that when filling Coralie, the incoming flow of nitrogen gas causes a drop in temperature. Therefore, during filling this is normal (after the observations and before noon)

In the case of pumping cryostats, the normal situation is to have a set point above 20d, because the pumping is done when the cryostats are hot. In this case there is nothing to do, all is under control.

Otherwise the actions to be taken are different depending on the instruments:

Concerning CORALIE

If the LN2 temperature (Azote) is written with white background (meaning above -180 Celsius), the CCD may be still OK, but you have to do a emergency manual filling NOW.

If the CCD temperature is not at the set point temperature, the measuring accuracy is lost. Therefore an emergency manual filling must be carried out and you have to observe with the camera until Coralie is ready again.

But if the temperature of the CCD is higher than -10 degrees (minus ten), emergency filling should not be performed because it is necessary to pump the cryostat before carry out a recooling.

In this last case, the nitrogen supply valve (#1) to Coralie must be closed to prevent automatic filling (and postpone the time to pump). Carry out this operation immediately:

Concerning the CAMERA (NECAM)

If the CCD temperature is not at the set point temperature, the measuring accuracy is lost.

In this case, nothing to do, the cooling is made in the instrument with a cryocooler. No action has to be taken, the support group is notified automatically by mail.

You must observe with Coralie.

LW 28/04/2020