SMPL
Smart Material Physics Lab

- Quantum Design MPMS-XL7 model with EverCool system.

- MPMS 관련 문제, 해결책, 원인에 대해 기록하자.

• Dewar pressure overshooting and/or undershooting

- He regeneration 이력을 기록하자.

• 2022.06.06, target He level: 63%

- SUPPLY PRESSURE INDICATION

• Monitor the compressor's supply He gas pressure. In the normal operation with adequate heat loads, the supply helium gas pressure indicates between 2.1 and 2.3 MPa (21.4 and 23.5 kgf/cm2G, 304 and 333 psig). The operating pressure varies according to the heat load of cold head and temperature around the equipment.

- HELIUM GAS CHARGING

• “IMPORTANT” The filling pressure of the cryocooler varies in accordance with the compressor and coldhead temperature. Make sure the cryocooler is powered off and compressor and coldhead temperatures are almost same as room temperature before adjusting the helium gas pressure.

• Charge helium gas, if the pressure indication of the Compressor Unit is lower than specified value. After stopping the cryocooler, the pressure indication on the Indoor Unit pressure gauge shows lower than actual filling pressure, because of the low temperature of the coldhead. The coldhead temperature and compressor unit temperature needs to be equal to ambient temperature to check the actual filling pressure.

• The filling pressure indication depends on the temperature of cryocooler components, such as Coldhead, Outdoor Unit, Indoor Unit and Flex Lines. In case the room temperature is relatively low, the filling pressure indicates lower. In case the room temperature is relatively high, the filling pressure indicates higher. Refer to the ambient temperature to adjust the filling pressure precisely.

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