EDEN - A Prototype 10mK Dry Dilution Refrigerator

许多先进的科学仪器需要冷却到接近绝对零度(0K)的温度。这种设备被用于先进的磁共振成像、扫描显微镜和用于量子计算的超导产生。实现这种低温的设备--稀释式冰箱--的工作原理是在封闭系统中以逐渐降低的温度蒸发液氦(He)，并由热交换器连接。在传统的“湿”系统中，初始冷却是简单地通过浸入液体氦来实现的，但他是一个有限的资源。目前全球约三分之一的消费量由美国储备库提供，该储备库成立于1925年，将在2020年至2030年间耗尽。这种情况意味着许多低温设备的新用户被阻止在超低温下工作，被迫选择“干式”稀释冰箱。这些系统没有任何“开放”的氦气。初始冷却采用封闭式系统，其中仍然含有氦，但需要每隔6个月进行少量补充，而不是每周对“湿”系统进行大规模补充。ICE牛津大学需要资金来开发工作在10mK的干式稀释制冷机原型。他们已经成功地交付了干式稀释系统，冷却到10、4K和1.5K。作为最近进入市场的公司，他们在根据用户需求进行定制方面取得了成功。他们的原型将包括一个中间冷却阶段，这是越来越需要更高功率的冷却应用，如量子计算。它还将展示一种集成的高场、高均匀、低衰减磁体，用于磁共振成像应用。它还将提供一个试验台来演示目前在其他地方正在开发的低温振动测量设备。一个成功的原型的影响将是允许尖端研究人员使用低温设备提供社会效益和经济效益，而不会产生不可持续的氦消耗。

Many advanced scientific apparatus needs cooling to temperatures approaching absolute zero(0K). Such apparatus is used in advanced magnetic resonance imaging, scanning probemicroscopy and generation of superconductivity for quantum computing. Equipment toachieve such low temperatures- dilution refrigerators- work by evaporating liquid helium (He)in closed systems at progressively lower temperatures, linked by heat exchangers. Intraditional “wet” systems, initial cooling is achieved simply by immersion in liquid He.However, He is a finite resource. Around 1/3 of current world consumption is supplied by theUS He reserve, which was set up in 1925 and will be exhausted between 2020 and 2030. Thissituation means that many new users of cryogenic equipment are prevented from performingwork at ultra-low temperatures, and are forced to opt for “dry” dilution refrigerators.These systems do not contain any “open” He. Initial cooling is provided closed systems,which still contain helium but require minor replenishment at ~6 month intervals, rather thanweekly major replenishment of “wet” systems.ICE Oxford need funding to develop a prototype dry dilution refrigerator working at <10mK.They have already successfully delivered dry dilution systems cooling to 10, 4K and 1.5K. Asa recent market entrant they have built success on customising to user requirements. Theirprototype will incorporate an intermediate cooling stage, which is increasingly required forhigher power cooling applications, such as quantum computing. It will also demonstrate anintegrated high field, high homogeneity, low decay magnet for use in MRI applications. It willalso provide a test bed to demonstrate low temperature vibration measurement equipment,currently under development elsewhere. The impact of a successful prototype will be to allow cutting-edge researchers to deliver societal and economic benefits using cryogenic equipmentwithout unsustainable He consumption.