Development and Testing of a Sensor for Liquid Helium Measurement

The cryogen is used in various industrial and commercial applications and the demand of the cryogens are increasing in recent years. It is necessary to measure the level of cryogen which is stored in the storage tank or dewar. It is necessary to maintain minimum cryogen level in the storage tank before filling it with a new batch of cryogen and preventing the thermal quench of superconducting equipment like superconducting magnets. Various methods are used for the measurement of cryogen. In recent years, superconducting liquid level sensor is used, however there is a drawback with this measurement unit as the sensor wire above the liquid level will be experiencing low temperature as compared to the sensor wire which is having contact with the gaseous form of cryogen. Hence, in this work, we have developed an indirect type super conducting liquid helium level sensor. The active length of the sensor developed is 40 inch and it was tested successfully. From this work, we conclude that developed sensor works effectively and will overcome the problem with super conducting level sensor.