2-STAGE PULSE TUBE REFRIGERATOR WITH DOUBLE ROTARY VALVES

We have constructed a two stage pulse tube refrigerator equipped with two rotary valves. The first stage regenerator was made of stainless s teel tube 39mm OD, 0.5mm thickness and 180mm long packed 1735 stainles s steel screens of 200 mesh and the second stage regenerator was made of stainless steel tube 18mm OD, 0.3mm thickness and 250mm long packed with stainless steel screen of 250 mesh and lead shots of about 0.3 m m diameter. The performance was investigated by changing the ratio of the stainless steel mesh and lead shots of the second regenerator and the volumes of first and second pulse tubes. The second stage cold end reached below 20K.