A Cold Cycle 3He/4He Dilution Refirgerator for milliKelvin cooling with an Intermediate Heat Sink at 1.4 Kelvin

As the size of quantum information systems (QIS) increases with technology development, the required cooling power at temperatures below 100mK will increase beyond that which currently available with commercially available milliKelvin cooler technologies. Additionally, as the size of QIS increases the number of electrical signal leads that require heat sinking in the 1K-temperature range will also increase. A substantial improvement in the cooling power in the 1 K range will be required in addition to increased milliKelvin cooling capacity. The ARS/ UWCEL team proposes to develop a continuous refrigerator capable of cooling to temperatures below 100 mK by implementing a cold cycle dilution refrigerator (CCDR) using a novel thermal magnetic pump technology. The CCDR will be precooled to 1.4 K by a 2 stage closed cycle cryocooler with an additional 3rd J-T stage. The Phase I effort will focus on developing the 1.4 K precooler and a piezoelectric superfluid valve technology that is a key component of the CCDR. In Phase I ARS will scale an existing 1.7 K cooling system to higher cooling power (150mW) and to a lower temperature (1.4 K). This will be accomplished by incorporating a larger 2-stage cryocooler and by redesigning the heat exchangers and throttle device in the J-T stage. Additionally, a piezoelectrically actuated superfluid valve technology will be developed that will enable a superfluid pump with no moving parts that has been developed by UWCEL to be adapted to drive the CCDR. This development effort at the completion of Phase II and beyond will lead to a commercially available integrated cryocooler product that not only provides high cooling power at temperatures below 100mK but also has significant cooling power at 1.4K for heat sinking electrical connections to the cold quantum information system devices. This product will have a market for researchers conducting QIS and low temperature detector development. This product will also have a market with suppliers of commercially available quantum computers when they become available.