Superconducting magnet systems
Standard system features:
- Top sample loading and exchange at all temperatures
- Effortless sample rotation and translation about the vertical axis at all temperatures, with options for rotation about a horizontal axis
- Field-independent thermometry
- The SuperVariTemp system, with provision for a temperature control thermometer at the heat exchanger
- Vapor cooled/superconducting high current magnet leads
- Superconducting magnets with persistent mode operation providing field stabilities of 20 ppm/h
- Carefully designed magnet support inside the helium reservoir, with optical access through the Dewar vacuum space (OptiMag and SuperOptiMag systems)
- Built-in superconducting liquid helium level sensors, providing continuous or timed level monitoring
- Readily accessible and interchangeable sample chambers
Complete systems include:
- Programmable magnet power supply with computer interface and bi-polar operation
- Temperature controller with field independent thermometry
- Liquid helium transfer lines
- Cryogenic Hall probe and gaussmeter
- Automatic nitrogen filling mechanism
- Vacuum pumping stations
This magnet requirements questionnaire contains several questions that will help our engineers determine the best system for your requirements.
Independent SuperVariTemp inserts
The SuperVariTemp (SVT) cryostat is a key component of all SuperVariMag, OptiMag, and SuperOptiMag systems. By controlling the temperature of the flowing helium vapor in which samples are immersed, the SVT allows for precise monitoring and control of sample temperature over a 1.5 to 325 K range, while eliminating the need for thermal anchoring and sample mount heating. The helium flow rate and heater are balanced to provide operation over the range of 4.2 K to 325 K; automatic temperature controllers equipped with field-independent thermometers provide accurate and precise temperature control.
The SVT cryostat allows full use of the cooling power of escaping helium vapor as it exits the sample chamber. The sample chamber is thermally isolated from the helium reservoir by the Dewar vacuum, thereby eliminating heat conduction into the reservoir. Precise sample temperature is measured through the use of a thermometer attached to the sample holder. Operation to 1.5 K is made possible by immersing the sample in liquid helium and reducing the pressure with a mechanical vacuum pump. The SVT's unique design also allows sample cooling in flowing helium vapor to approximately 2 K for extended operation below 4.2 K without the need to monitor or replenish the helium level in the sample chamber. For optical experiments, this presents the least interference to the incoming and scattered beams.
The SVT insert is available as an accessory for existing superconducting magnets. A custom-designed SVT cryostat can be matched to the dimensions of an existing open neck Dewar and magnet bore. Drawing liquid helium from the main magnet reservoir, the SVT insert will provide temperatures of 1.5 K to 325 K without the need for pumping on the main reservoir.
It is also available in a high-stability or a high-temperature static gas insert option for applications requiring a high stability region, continuous operation above 100 K, for high sensitivity experiments that preclude locating the sample in flowing helium vapor. Special sample positioners can also be supplied for temperatures of 400 K or higher along with optional wiring and cold, detachable wiring stages.