Dry dilution refrigerator with pulse-tube precooling

We present construction details and performance measurements of a dry dilution refrigerator which is precooled by a pulse-tube refrigerator; no cryo-liquids are required to operate this cryostat. The dilution refrigerator is equipped with a double mixing chamber and reaches a lowest temperature of 4.3 mK. The He-3 throughput of the refrigerator was between 100 and 300 mumol/s. The total heat leak into the mixing chamber was determined to be 75 nW. For thermometry we had a He-3 melting-curve thermometer at our disposal. Ease of operation and reliability are the characteristics of this type of cryostat. (C) 2003 Elsevier Ltd. All rights reserved.