Superconducting properties of ultra-pure niobium welded joints

Abstract

An optimal electron-beam welding operating regime for ultra-pure sheet niobium has been developed for use in a superconducting resonator for the International Linear Collider (ILC). The formation of weld joints is studied and their microstructure and microhardness are investigated taking the required geometry of the weld seams into account. Low-temperature electrical measurements in magnetic fields up to 2 T are used to determine the critical parameters of the superconducting transition in the weld area. From the standpoint of the superconducting properties of the resonator, the slight degradation in the characteristics of sheet niobium observed in the thermally affected area (about 10% on average) is not of fundamental importance. V C 2015 AIP Publishing LLC. [http://dx.

A novel Nb superconducting joint with ultralow resistance fabricated by electron beam welding method for superconducting gravimeter

“…Electron beam welding (EBW) has the advantages of local high-energy and high-vacuum working environments and has been widely used in refractory metals and alloys, such as W [9], Mo [10], Ta [11], and Nb [12]. Additionally, EBW has been successfully used for welding pure Nb to the resonant cavities of modern accelerators [13,14]. It has been proven that the superconducting properties of Nb materials are not degraded by the EBW process [13][14][15][16][17][18].…”

“…Additionally, EBW has been successfully used for welding pure Nb to the resonant cavities of modern accelerators [13,14]. It has been proven that the superconducting properties of Nb materials are not degraded by the EBW process [13][14][15][16][17][18]. However, there are no reports of Nb superconducting joints being fabricated using the EBW method.…”