Laboratory helium liquifier for supersolid research

这是一项为低温物理实验室购置小型氦气液化器的建议。该液化器的研究将涉及在高压和超低温下对固体氦的实验研究，这是最近发现的一种新的物质“超固体”相。由于需要极低的温度（在绝对零度的0.2度以内），所有这样的实验都需要使用强大的“稀释冰箱”，它使用大量的液氦来操作。氦气是一种昂贵且不可再生的资源，但最近低温技术（脉冲管冰箱）的发展大大降低了小规模回收和再液化氦气的成本。这个提议中的氦气液化器将允许我们回收液氦沸腾时产生的气体，每天产生多达20升的液氦。这将使我们能够持续操作稀释冰箱，更有效地进行更多的实验。它每年还将节省大约200万升氦气。这将每年节省约30,000美元的液氦成本，并在3年内收回投资。节省下来的费用将用于支持研究生在低温和实验凝聚态物理方面的培训。

This is a proposal to acquire a small-scale helium liquifier for a low temperature physics laboratory.  The research that will be enabled by this liquifier involves experimental studies of solid helium at high pressures and ultralow temperatures, a regime where a new "supersolid" phase of matter was recently discovered.  Because of the extremely low temperatures needed (within 0.2 degrees of absolute zero), all such experiments require the use of a powerful "dilution refrigerator", which uses substantial amounts of liquid helium to operate.  Helium is an expensive and non-renewable resource but recent developments in cryogenic technology (pulse tube refrigerators) have dramatically reduced the cost of recovering and reliquifying helium on a small scale.  The helium liquifier in this proposal will allow us to recycle the gas produced as the liquid helium boils off and produce up to 20 liters of liquid helium per day.  This will allow us to continuously operate our dilution refrigerator and perform more experiments, more effectively.  It will also conserve approximately 2 million liters of helium gas each year.  This will save approximately $30,000 per year in liquid helium costs, repaying the investment within 3 years.  The cost savings will be used to support graduate students being trained in low temperature and experimental condensed matter physics.