Liquid Helium Bath Free, Conduction Cooled Nb3Sn Superconducting 7 Tesla Plus Mag

描述(申请人提供)：对于7特斯拉全身MRI钻孔磁体系统，NbTi超导丝在4K以上7T时已达到极限。如果使用NbTi，则需要将氦过冷至1.8-2.4K才能实现7-11T钻孔MRI和核磁共振系统。所有这些由西门子、飞利浦和通用电气销售的7T全身MRI背景磁铁都是由Aligent(之前在MagneX之前的瓦里安)制造的。Aligent最近宣布，他们将不再接受这些7T磁铁的订单，并确定氦的成本和可获得性。由于交货问题和氦气短缺，一些MRI制造商已经停止接受7T MRI的新订单。医学界希望看到7T磁共振成像成为一种临床系统。因此，价格需要大幅下降，从长远来看，唯一真正的解决方案是让传导冷却磁体将氦短缺的问题排除在方程式之外。Nb_3Sn超导线材在10~(-16)T的高场下具有较高的电流密度，是这些应用的理想选择。另外，转变温度(T_C)较高 Nb3Sn17K，NbTi9K。当大型NbTi磁体在液氦浴中冷却时，线圈内的温差需要小于1K。在7K时，Nb_3Sn仍然保持其工程电流密度的1/2以上，以便在大型磁体的内孔中设计7-12T的磁场，并提供2-3K余量以实现传导冷却，并且可以消除对液氦浴冷却的需要。这样，每次磁铁需要冷却时(在工厂培训磁铁、在医院安装磁铁，以及当磁铁在其7-10年的使用生命周期内多次淬火时)，都不需要4000-6000升氦。海珀科技开发了一种低成本、高性能的管状Nb3Sn型超导体，这是开拓这一市场的极佳线材候选材料，使我们能够实现医用大传导冷却Nb3Sn磁体的具体目标。随着性能的提高，它可以经济地实现传导冷却磁体，并消除氦的批量冷却。这种新的，Hyper Tech，低成本，高性能(4.2K-12T时JC为2000A/mm2)Nb3Sn超导线可以降低导线成本-与用于7特斯拉全身MRI的NbTi导线相比。这将极大地降低磁铁的重量和尺寸。它还将使4-7K范围内的传导冷却成为可能。在这个快速通道第一阶段和第二阶段项目中，我们将展示由海珀科技开发的一种新的低成本Nb3Sn超导体可用于制造用于7T特斯拉磁共振和核磁共振系统的大型传导冷却50-100厘米钻孔线圈。这将使公众受益于需要高分辨率和快速成像的核磁共振和核磁共振应用。这与NIH向公众提供成本效益高的更好的医疗保健的使命相匹配。

DESCRIPTION (provided by applicant): For 7 tesla full body MRI bore magnet systems, NbTi superconductor wire has reached its limit at 4 K. Above 7T if NbTi is used it requires super cooling of helium to 1.8-2.4 K to achieve 7-11T bore MRI and NMR systems. All these 7T full body MRI background magnets sold by Siemens, Philips, and GE have been manufactured by Aligent (formerly known at Varian before that Magnex). Aligent recently announced that they will no longer accept orders for these 7T magnets and sited costs and availability of helium. Some MRI manufacturers have stopped accepting new order for 7T MRIs because of delivery issues and helium shortages. The medical community would like to see 7T MRI's become a clinical system. Hence, the price needs to come down dramatically and in the long run the only real solution is to have conduction cooled magnets to take the helium shortage issue out of the equation. Nb3Sn superconductor wire is the ideal candidate for these applications due to its higher current density at higher field like 10-16T. Plus, the transition temperature (Tc) is higher 17K for Nb3Sn vs. 9K for NbTi. When a large NbTi magnet is cooled in a liquid helium bath, the temperature differential in the coil needs to be less than 1K. At 7K Nb3Sn still retains over 1/2 its engineering current density to enable the design of 7-12T magnetic fields in the bore of large magnets, and it provides the 2-3K margin to enable conduction cooling and can eliminate the need for liquid helium bath cooling. This eliminates the need for 4000-6000 liters of helium every time the magnet needs to be cooled down (training the magnet in the factory, setting up the magnet at the hospital, and when the magnet quenches several times over its useful life cycle of 7-10 years). What enables our specific aim of large conduction cooled Nb3Sn magnets for medical applications is that Hyper Tech has developed a low cost and high performance tube type Nb3Sn superconductor which is an excellent wire candidate to open up this market. With the increase in performance it can economically enable conduction cooled magnets and eliminate the helium batch cooling. This new, Hyper Tech, lower cost, high performance (Jc of 2000A/mm2 at 4.2K-12T) Nb3Sn superconductor wire could cut the wire cost -compared to NbTi wire for a 7 Tesla full body MRI. It would dramatically decrease the magnet weight and size. It will also make the conduction cooling possible for the 4-7K range. During this Fast Track Phase I and Phase II project we will demonstrate that a new low cost Nb3Sn superconductor developed by Hyper Tech can be used to fabricate large conduction cooled 50-100 cm bore coils for 7T tesla MRI and NMR systems. This will benefit the public for MRI and NMR applications that require high resolution and rapid imaging. This matches NIH's mission of delivering cost effective improved health care to the public.