Isolation Vacuum

A high vacuum oil-diffusion pump, OVP91130, is used to evacuate the cryostat's isolation vacuum (IV). Once the cryostat is cold, a gate valve (PV91104) between the pump and cryostat is closed. The vacuum on the cryostat side if the gate valve is measured by a cold cathode cathode gauge, PI91131, while a Pirani gauge, PI91132, is used on the pump side of the valve. Both gauges are controlled by a Pfeiffer dual gauge controller which is read into the IOC via two ADC channels.

Inexperienced target operators are forbidden to operate the IV controls.