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

无液氦浴、传导冷却 Nb3Sn 超导 7 Tesla Plus Mag

• 批准号: 8647926
• 负责人: Xuan Peng
• 金额: $ 15.03万
• 依托单位: HYPER TECH RESEARCH, INC.
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-19 至 2015-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8647926
• 关键词: Bathing; Beryllium; Caliber; Clinical; Communities; Copper; Development; Dimensions; Elements; Engineering; Environmental Wind; Equation; Filament; Healthcare; Heating; Helium; Hospitals; Hybrids; Image; Joints; Length; Life Cycle Stages; Liquid substance; Magnetic Resonance Imaging; Magnetism; Manufacturer Name; Marketing; Medical; Mission; Modeling; Particle Accelerators; Performance; Phase; Price; Procedures; Property; Resistance; Resolution; Site; Solutions; Stainless Steel; System; Temperature; Testing; Time; Training; Transition Temperature; Tube; Weight; cost; cost effective; cryostat; density; design; improved; innovation; magnetic field; meter; public health relevance; research and development; thermal stress

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.

描述（由申请人提供）：对于 7 特斯拉全身 MRI 孔磁体系统，NbTi 超导线材在 4 K 时已达到其极限。如果使用 NbTi 高于 7T，则需要将氦气过冷至 1.8-2.4 K 以实现 7-11T钻孔 MRI 和 NMR 系统。西门子、飞利浦和 GE 销售的所有这些 7T 全身 MRI 背景磁体均由 Aligent（以前称为 Magnex）制造。 Aligent 最近宣布，他们将不再接受这些 7T 磁铁的订单，并确定了氦气的成本和可用性。由于交货问题和氦气短缺，一些 MRI 制造商已停止接受 7T MRI 的新订单。医学界希望看到 7T MRI 成为一个临床系统。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使用传导冷却磁体来解决氦短缺问题。 Nb3Sn 超导线材是这些应用的理想选择，因为它在 10-16T 等较高磁场下具有较高的电流密度。另外，转变温度 (Tc) 更高 Nb3Sn 为 17K，NbTi 为 9K。当大型NbTi磁体在液氦浴中冷却时，线圈中的温差需要小于1K。在 7K 时，Nb3Sn 仍保留超过 1/2 的工程电流密度，以便能够在大型磁体的孔中设计 7-12T 磁场，并且提供 2-3K 余量以实现传导冷却，并且无需液氦浴冷却。这样，每次需要冷却磁体时（在工厂训练磁体、在医院安装磁体，以及当磁体在其 7 的使用寿命周期内多次淬火时），就无需使用 4000-6000 升氦气。 -10 年）。我们实现医疗应用大型传导冷却 Nb3Sn 磁体这一特定目标的原因是，Hyper Tech 开发了一种低成本、高性能的管式 Nb3Sn 超导体，它是打开这一市场的绝佳线材候选者。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批量冷却。与用于 7 特斯拉全身 MRI 的 NbTi 线相比，这种新型超技术、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。它将大大减少磁铁的重量和尺寸。它还将使 4-7K 系列的传导冷却成为可能。在 Fast Track 第一阶段和第二阶段项目中，我们将展示由 Hyper Tech 开发的新型低成本 Nb3Sn 超导体可用于制造用于 7T 特斯拉 MRI 和 NMR 系统的大型传导冷却 50-100 cm 孔径线圈。这将使公众受益于需要高分辨率和快速成像的 MRI 和 NMR 应用。这符合 NIH 向公众提供具有成本效益的改善医疗保健的使命。