Cryocooled Biomagnetometer

描述（由申请人提供）：我们建议研究和确定开发用于低温冷却多通道大型生物磁系统的新方法的可行性。机械制冷是唯一能够提供冷却大型生物磁系统所涉及的经济收益的技术。拟议的设计将使这些系统在运行和维护方面更具经济吸引力，并减少与液氦持续处理相关的物流。基于SQUID操作的生物磁力计装置总是需要液体冷冻剂， 手术。通常，该操作的成本可以在50 - 250万美元的范围内，这取决于系统的类型和检测通道的数量。因此，一个典型的MEG装置每年将消耗20，000 - 40，000美元的液氦。虽然液氦的经济性在过去并不是生物磁性仪器扩散的主要抑制因素，但稀缺性和不断增加的成本可能会改变这一点。机械闭合循环制冷机已成为使用液体制冷剂的替代品。这些优点包括降低运营成本、在偏远地区使用、在非垂直方向上运行、避免制冷剂输送中断、安全性以及不必每隔几天就转移一次的便利性。使用具有SQUID的闭合循环制冷存在两个主要障碍。第一个是机械运动，（最终）导致检测线圈在地球磁场中移动。第二个是由于制冷机的冷头和压缩机的运动部件产生的磁特征。所提出的设计不仅在美国，而且特别是在欧洲和亚洲国家，可以显著增加大型生物磁力计系统的市场，因为缺乏外国氦气源导致相关成本是美国成本的两倍。此外，由于工业需求的增加，氦短缺正在发展。

DESCRIPTION (provided by applicant): We propose to study and determine the feasibility of developing a novel approach for a cryocooled multichannel large biomagnetic system. Mechanical refrigeration is the only technique capable of providing the economical gains involved in cooling large biomagnetic systems. The proposed design would make these systems more economically attractive to run and maintain as well as reducing the logistics associated with constant handling of liquid helium. Biomagnetometers installations based on SQUID operation have always required liquid cryogens to operate. Typically this operation can run a cost in the range from 0.5 - 2.5 million dollars depending on the type of system and number of detection channels. Thus a typical MEG installation will consume $20,000 -$40,000 of liquid helium annually. While the economics of liquid helium have not been a major inhibitor to the diffusion of biomagnetic instrumentation in the past, scarcity and increasing costs could change that. Mechanical closed cycle refrigerators has become an alternative to the use of liquid cryogens. These include reduction of operating costs, use in remote locations, and operation in non-vertical orientations, avoiding interruptions in cryogen deliveries, safety, and the convenience of not having to transfer every few days. There are two main obstacles to using closed cycle refrigeration with SQUIDs. The first is the mechanical movement that (ultimately) causes the detection coils to move in the Earth's magnetic field. The second is the magnetic signature due to the moving parts of the cryocooler's cold head and compressor. The proposed design could significantly increase the market for large biomagnetometer systems not only in the US but also especially in European and Asian countries because of the lack of foreign helium gas source causing the associated costs to be twice the US costs. In addition, a helium shortage is developing due to increasing demand in industrial.