Design, analyses, fabrication and characterization of Nb3Sn coil in 1 W pulse tube cryocooler

26th International Cryogenic Engineering Conference & International Cryogenic Materials Conference 2016

材料科学;物理学

Kundu, Ananya^1 ; Das, Subrat Kumar^1 ; Bano, Anees^1 ; Kumar, Nitish^1 ; Pradhan, Subrata^1

Institute for Plasma Research, Bhat, Gandhinagar

Gujarat

382428, India^1

关键词: Conduction-cooling;    Fabrication and characterizations;    Force component;    Magnetic field profile;    Operational conditions;    Pulse tube cryocoolers;    Radial direction;    Wind-and-react method;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/171/1/012106/pdf
DOI  :  10.1088/1757-899X/171/1/012106

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

A laboratory scale Nb3Sn coil is designed, analysed, fabricated and characterized in 1 W pulse tube cryocooler in solid nitrogen cooling mode and in conduction cooling mode. The magnetic field profile in axial and radial direction, Lorentz force component across the winding volume in operational condition are estimated in COMSOL. The coil is designed for 1.5 T at 100 A. It is fabricated in wind and react method. Before winding, the insulated Nb3Sn strand is wound on a copper mandrel which is thermally anchored with the 2ndstage of the cold head unit via a 10 mm thick copper 'Z' shaped plate The temperature distribution in 2ndcold stage, copper z plate and coil is monitored in both solid nitrogen cooling and conduction cooling mode. In solid nitrogen cooling mode, the quench of the coil occurs at 150 A for 0.01 A/s current ramp rate. The magnetic field at the centre of the coil bore is measured using transverse Hall sensor. The measured magnetic field value is compared with the analytical field value and they are found to be deviating ∼5% in magnitude. Again the coil is tested in conduction cooling mode maintaining the same current ramp rate and it is observed that the coil gets quenched at 70 A at temperature ∼ 10K.