Construction of a Cryogenic Magnet for Quasi-Steady High Magnetic Fields

准稳态高磁场低温磁体的构建

• 批准号: 01840006
• 负责人: NAKAGAWA Yasuaki
• 金额: $ 6.27万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Developmental Scientific Research (B).
• 财政年份: 1989
• 资助国家: 日本
• 起止时间: 1989 至 1990
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-01840006/
• 关键词: high magnetic field; quasi-steady field; resistive magnet; cryogenic magnet; long-pulsed magnet

1. Design and fabrication of cryogenic magnet(1) Coil : This magnet is operated at liquid nitrogen temperature, consisting of an outer Bitter coil and an inner polyhelix coil. The electromagnetic force and the Joule heat dissipation were carefully taken into account for designing the magnet.(2) Power supply : A high-power DC source for steady high field magnets was modified with a pulse operation circuit so as to serve for the quasi-steady cryogenic magnet. The current is increased to 23 KA ror 1 or 2 seconds, and kept at 23 KA for 0-3 seconds.(3) Cryostat : Liquid nitrogen is supplied from a large reservoir of 9 m_3 capacity, and circulated through the magnet coils in a cryostat.2. Test of cryogenic magnet(1) Excitation at room temperature : The resistance of the coils is so large at room temperature that only a small current can be passed through the coils. Under this condition, however, the characteristics of the power supply and the heating of the coils were tested. No unexpected results were obtained.(2) Cooling down to liquid nitrogen temperature : It took 10 minutes to cool down the coils from 300 K to 77 K.(3) Excitation at liquid nitrogen temperature : The coil resistance is reduced to about 1/8 of that at room temperature so that a large current is passed through the coils. Although the excitation should be made during the circulation of liquid nitrogen, the circulation was stopped before the excitation in the present test : the coils heated by the excitation was cooled again by circulating liquid nitrogen. The field produced by the magnet was in good agreement with the designed value. The cryogenic magnet has not been applied for the measurement of physical properties at high fields. It should be emphasized, however, that the main purpose of this research is to clarify the characteristics of the quasi-steady cryogenic magnet.

1. 低温磁体的设计和制造 (1) 线圈：该磁体在液氮温度下工作，由外部 Bitter 线圈和内部多螺旋线圈组成。磁体的设计充分考虑了电磁力和焦耳热耗散。(2)电源：对高功率稳态强磁场磁体直流电源进行脉冲运算电路改造，为准稳态低温磁体提供电源。电流增加到23 KA或1或2秒，并保持在23 KA 0-3秒。 (3)低温恒温器：液氮由9 m_3容量的大储液器提供，并通过低温恒温器中的电磁线圈循环。2．低温磁体测试（1）室温励磁：室温下线圈的电阻很大，只能通过很小的电流。然而，在此条件下，测试了电源特性和线圈加热特性。没有得到意想不到的结果。(2)冷却至液氮温度：用10分钟将线圈从300K冷却到77K。(3)液氮温度励磁：线圈电阻降低至室温时的约1/8，从而使大电流通过线圈。尽管应在液氮循环期间进行励磁，但在本试验中，在励磁之前停止循环：通过励磁加热的线圈再次通过循环液氮冷却。磁铁产生的磁场与设计值非常吻合。低温磁体尚未应用于高场物理特性的测量。但需要强调的是，这项研究的主要目的是阐明准稳态低温磁体的特性。

项目成果

Y. Nakagawa et al.: "High Field Magnet at Sendai" Physica B. Vol. 164. 29-34 (1990)

Y. Nakakawa 等人：“仙台的高场磁铁”Physica B. Vol.

Y.Nakagawa et al.: "High Field Magnets at Sendai" Physica B. 164. 29-34 (1990)

Y.Nakakawa 等人：“仙台的高场磁铁”Physica B. 164. 29-34 (1990)

Y.Nakagawa et al.: "A Design of 50T Hybrid Magnet for QuasiーStationary Operation" Proceedings of 11th International Conference on Magnet Technology (Elsevier). 1. 633-638 (1990)

Y. Nakakawa 等人：“用于准静止操作的 50T 混合磁体的设计”第 11 届国际磁体技术会议论文集 (Elsevier) 1. 633-638 (1990)。

Y. Nakagawa et al.: "A Design of 50 T Hybrid Magnet for Quasi-Stationary Operation" Proceedings of 11th International Conference on Magnet Technology, (Elsevier). Vol. 1. 633-638 (1990)

Y. Nakakawa 等人：“用于准静止操作的 50 T 混合磁体的设计”第 11 届国际磁体技术会议论文集（爱思唯尔）。

Y.Nakagawa et al.: "A Design of 50T Hybrid Magnet For Quasi-Stationary Operation" Proceedings of 11th International Conference on Magnet Technology(Elsevier Science Publishers Ltd.).

Y.Nakakawa 等人：“A Design of 50T Hybrid Magnet For Quasi-Stationary Operating”第 11 届国际磁体技术会议论文集（Elsevier Science Publishers Ltd.）。