Vacuum controll

A vacuum controll instruments are implemented in the cryostat. As a pump functions the HighCube 80eco, as a sensor a PKR 251 connected to a TPG361 is used, all from PFEIFFER Vacuum. A solenoid valve is implemented in the system to separate the cryostat from the pump. As a solenoid valve funtions the 0211 from Bürkert, it is a normally closed device, meaning applying energy will open the device. If it's Powered on it connects the pump to the chamber. Furthermore, the vacuum pump and the solenoid valve are both controlled via the PDU, while the single gauge is controlled via a LabVIEW Script via the server.

1. Ensure that cryocooler is off and cryostat is at room temps!
2. Turn on main power switch on HiCube Eco 80
3. Wait for DCU to complete self-test of system
4. Check if venting is off under parameter 012 “Enable vent” ⇒ off
5. Turn on roughing pump: Select parameter 010 “Pumping station” ⇒ on
6. Once we reach pressures !!< 5 mbar!!, select parameter 023 “ motor pump” and turn on turbomolecular pump
7. Ideally, we want pressure to drop to lower 10^(-6) mbar range

1. Turn cryocooler off and wait for temperatures to reach ~ 280 K
2. Turn off Turbomolecular pump and wait for RPMs to go to zero
3. Turn off roughing pump
4. Vent the system

The pressure within the Cryostat is monitored with a Single Gauge TPG361 from Pfeiffer Vaccum, which uses a PKR 251 FPM-sealed, DN 25 ISO-KF gauge sensor. The maximum pressure applies to inert gases and temperatures below 55 °C and is corrosion resistant. The TPG361 is designed for installation to a 19“ rack chassis adapter according to DIN 41494 and provides serial communication via R485 (24V, 5-pin circular), USB and Ethernet interfaces.It is used to measure the pressure inside the chamber.

• Front panel Operation: Manual
• Supported Commands: Communication protocol
• Data Format: 1 start bit, 8 data bits, no parity bit, 1 stop bit, no hardware handshake

The HighCube 80 eco from Pfeiffer is uses as a turbumolacular vacuum pump. It allows for a pressure range below 10e(-7)pa. It is possible to remote controll the pump, for this a RS-485 to LAN converter is installed (Moxa Serial LAN device).

* Manual

For better understanding on how the different components of the vacuum subsystem are linked together, the following scheme is provided:

The Pfeiffer Vacuum's HighCube 80eco consist of multiple subsystem, in the following table it is shown which setup uses what kind of subsystem: