The standard SuperVariMag systems offer magnetic fields of 6-9 Tesla (niobium titanium coils) and 10–14 T (niobium tin coils), sample tubes of 1.0"-1.5" diameter and a 20 liter useful capacity open neck helium reservoir in a vapor shielded superinsulated dewar. While the standard systems offer a vertical magnetic field, split pair coils along with double or triple coil configurations are also offered in various field strengths for horizontal field directions or rotating vector fields. Please contact Janis for a list of available designs or for a custom designed magnet system.
SuperVariMag systems can also be supplied in larger helium capacity dewars, where a "belly" in the helium reservoir provides an increased helium capacity above the magnet. They can also be supplied in an ultra low loss (ULL) cryostat that offers a static loss rate between 4 and 5 liters a day, with the magnet and variable temperature insert in position. The high efficiency systems usually incorporate a low current magnet design and a cryostat with a nitrogen reservoir, superinsualtion, and an additional radiation shield between the helium and nitrogen reservoirs to provide the ultimate efficiency in a top loading system.
When required, Janis also offers 9 T/11 T up to 14 T/ 16 T magnets with a Lambda point refrigerator (LPR) for operation at the higher field, with the reservoir at atmospheric pressure. SuperVariMag systems offer efficient cost effective systems with static hold times that range from two to ten days, and are available with field homogeneities of 0.5% and 0.1% over a 1 cm diameter sphere. Larger sample tubes (3-4" OD), and higher field homogeneities (0.01 % or better over 1 cm diameter sphere) and special field profiles are available. Non-optical experiments such as critical current, resistivity, specific heat, Hall effect, etc. are easily performed with a SuperVariMag system. With the addition of appropriate gradient, modulation and pick-up coils, the SuperVariMag system is easily adapted for use in Faraday Balance susceptometry, vibrating sample magnetometry, etc.
The SuperVariMag series may be used in conjunction with an optional Independent magnet support and wiring system, thus allowing a magnet to be used with more than one insert (He3 or Dilution Refrigerator). In this configuration, the SVT Insert can be introduced and removed without disturbing the magnet.
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