Design of Still for Dilution Fridge

In view of indigenous development of a dilution fridge at VECC, Kolkata, we have designed a 3He distillation chamber (Still) of 40 cc volume for efficient evaporation of 3He from the dilute solution. To ensure the requisite cooling power of the dilution fridge we have chosen, manganin wire heater (∼400Ω) is glued tn the exterior to the Still body. The Still is made of OFHC Cu. To reduce the 4He film flow, the diameter of 23 mm is used for the exit path in the pump-out line. The estimated Still power is of ∼0.6 mW. RuO temperature sensor is tightly fitted with the still in an appropriate boring. A typical circulation rate of 15 μmol/s of 3He is considered for the fridge (estimated cooling power -10 μWatt @100 mK). This paper presents the detailed mechanical design along with analytical results of Still with film flow suppressor.