Recently the UHV arc technology was proposed as a possible alternative for depositing thin superconducting films of pure niobium on the inside surface of RF cavities for particle accelerators. The paper describes status of research on deposition of superconducting films for RF accelerating cavities. New UHV arc based devices with planar and cylindrical niobium cathodes are presented. The main r...

The focus of this project was to design and construct a model controlled-flow apparatus to study electropolishing of one cm 2 niobium coupons at surface flow rates typical of cavity processing. A simulation of the apparatus was constructed using CFDesign, a flow and thermal simulation software, to ensure that the selected dimensions may be expected to provide steady-state, laminar flow across t...

In order to test the microwave properties of superconductors, we are developing a disk resonator, to be operated in the TM010 mode at 3.36 GHz. The goal is a measurement of microwave surface resistance at both low and high power, initially for niobium thin films, but eventually for other thin film superconductors. The currents in a disk resonator flow in and out radially. Edge currents are zero...

We report on the preparation of carbon nanotube Josephson junctions using superconducting electrodes made of niobium. Gate-controllable supercurrents with values of up to 30 nA are induced by the proximity effect. The IV curves are hysteretic at low temperature and the corresponding switching histograms have a width of 0.5%–2%. An on-chip resistive environment integrated in the sample layout is...

Superconducting radio frequency (SRF) cavities for particle accelerators are fabricated using high purity niobium to allow for continuous high power operation. A hot-spot generated at a surface defect during accelerator operation can quench superconductivity and limit its performance. Increased heat conduction to the liquid helium bath dissipates hot spots, maintaining performance. Properly tre...

Niobium based super alloys are an unusual class of metallic materials with an exceptional combination of high temperature strength, toughness, and resistance to degradation in corrosive or oxidizing environments. The focus of present work was to study the effect of cutting parameters – speed, feed and depth of cut on the machinability of Niobium C-103 under dry machining condition using respons...