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 to the exterior to the Still body. The Still is made of OFHC Cu. To reduce the ⁴He film flow, the diameter of 2.5 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.