CryoTigers

The CryoTigers have a filter that needs to be replaced occasionally. One of the newer CryoTigers we have has an inbuilt filter that needs to be replaced by the manufacturer, i.e., the whole compressor needs to be sent for maintenance. Later versions allow for the inbuilt filter to be replaced, and we only need to purchase the filter. This is both cheaper and more convenient. We are checking with the manufacturers if they can change the inbuilt filter with a permanent fitting, to one that can be change by us.

Two sets of (spare) CryoTiger hoses were repaired, cleaned with acetone, vacuum pumped, and refilled with gas, and are ready for use.

A new, faster procedure to wash the CryoTiger head was developed and tested. The procedure has been documented and added to the web.

Each semester we have a few cases were for unclear reasons there is a spontaneous drop in cooling capacity of a CryoTiger resulting in a rise of detector temperature and reduction of vacuum. In general, pumping the dewar and power-cycling the compressor a few times returns the system to normal.