Finally, the simplicity of cryogen-free system operation is very attractive. Simply plug in the cryocooler and operate the system. Today's cryocoolers are very reliable with minimal routine maintenance. The 4.2K Gifford-McMahon based systems by Cryomagnetics offer the flexibility of up to 1.5 watts cooling power at 4.2K and the capability of orienting the cold head in any position. A popular configuration involves mounting the magnet system on a stand that allows rotation of the room temperature bore, allowing access in either vertical or horizontal positions.
Compressors are available in either air or water cooled.
4.2K Gifford-McMahon cryocoolers are used extensively throughout the world and enjoy an excellent reliability record. Eliminating the displacer in the cold head simplifies construction and increases reliability. Cryomagnetics manufactured the first commercially-available superconducting magnet system based on a 4.2K pulse tube in 1999. Since that time, 4.2K pulse tube systems have become increasingly popular. At present, the 4.2K pulse tube cryocooler is available with 0.5 watts cooling power at 4.2K and a water-cooled compressor.