A versatile cryocooled 15 T superconducting magnet with a room-temperaturebore and an optical window

A close-cycle cryocooled Nb3Sn superconducting magnet, using a single coil along with leads of the 2223 bismuth cuprate high-temperature superconducto r, has been designed and fabricated. The magnet achieves a field up to 15 T and has a room-temperature bore of 52 mm as well as an optical window. The cooling-down time from room temperature to 3.5 K is 13 h, The maximum fiel d attainable is 15 T for 3 h and 14.5 T for continuous use. This magnet wil l be specially useful in laboratories where liquid helium is not readily av ailable.