Compact bath cryostat filled with liquid helium inside an ordinary storageDewar

An economical bath cryostat for optical and galvano-magnetic measurements i s described. The small overall diameter of the cryostat allows filling with liquid helium directly upon immersion into an ordinary storage Dewar vesse l. As a result, it needs no more than 0.2 l of liquid helium for a single c ycle of low-temperature measurements outside the storage Dewar lasting 1.5- 4 h. Simplicity and low cost are other advantages of the cryostat. The basi c ideas used in this device are the mobility of a helium can relative to th e external body of the cryostat and the essential increase of the helium bo iling point if pressure increases up to 0.5-1.5 atm over atmospheric pressu re. (C) 2001 American Institute of Physics.