High Q radio frequency circuits employing a superconductive layer on a thermally matched aggregate metallic substrate
High Q radio frequency circuits such as reference cavity resonators for frequency standards and coupled cavity circuits for linear accelerators are disclosed. Such circuits comprise a radio frequency wave supporting structure formed by a superconductive layer deposited upon or otherwise formed on a metallic substrate member. The substrate is matched to the coefficient of linear thermal expansion of the superconductive layer such that thermally produced strains of the superconductive layer are prevented in fabrication and use. The metallic substrate member is formed of a porous metal structure of a first metal having substantial strength with the pores infiltrated with a second metal having a relatively high thermal conductivity at cryogenic temperature, as of 1.85/sup 0/K. Suitable superconductive layers include niobium, niobium-tin, niobium-zirconium, niobium-titanium, tantalum, and vanadium. Suitable aggregate substrate materials include a tungsten or niobium porous metal matrix impregnated with a good thermal conductor such as copper or silver. In a preferred embodiment, pure niobium is deposited upon a substrate member comprising a porous tungsten matrix impregnated with purified annealed copper with the substrate comprised of about 65 percent by volume of tungsten and 35 percent by volume of copper. The superconductive layer is preferably polished, as by chemical polishing or electropolishing, to remove surface irregularities greater than 1 micron in size. X-band linear accelerator cavities constructed according to the present invention provide Qs of the order of 10/sup 8/ to 10/sup 9/.
- Assignee:
- Varian Associates
- Patent Number(s):
- US 3441881
- OSTI ID:
- 5334716
- Resource Relation:
- Patent File Date: Filed date 20 Apr 1967
- Country of Publication:
- United States
- Language:
- English
Similar Records
Eco-Friendly Bipolar Electrochemical Bulk Processing of SRF Cavities
Insights to Superconducting Radio-Frequency Cavity Processing from First Principles Calculations and Spectroscopic Techniques
Related Subjects
GENERAL PHYSICS
43 PARTICLE ACCELERATORS
SUPERCONDUCTING CAVITY RESONATORS
FABRICATION
LINEAR ACCELERATORS
MICROWAVE EQUIPMENT
POLISHING
QUALITY FACTOR
SUBSTRATES
SUPERCONDUCTING FILMS
THERMAL EXPANSION
ACCELERATORS
CAVITY RESONATORS
CYCLIC ACCELERATORS
ELECTRONIC EQUIPMENT
EXPANSION
FILMS
SUPERCONDUCTING DEVICES
SURFACE FINISHING
420201* - Engineering- Cryogenic Equipment & Devices
430300 - Particle Accelerators- Auxiliaries & Components