Progress Report For A New Cryogenic Sapphire Oscillator

This paper present design progress and subsystem test results for a new short-term frequency standard, the voltage controlled sapphire oscillator (VCSO). Included are sapphire resonator and coupling design, cryocooler environmental sensitivity tests, Q measurement results, and turnover temperature results. A previous report presented history of the design related to resonator frequency and frequency compensation. Performance goals are a frequency stability of 1times10^-14 (1 second < tau < 100 seconds) and two years or more continuous operation. Long-term operation and small size are facilitated by use of a small Stirling cryo-cooler (160W wall power) with an expected 5 year life