title: Long-term operation and performance of cryogenic sapphire oscillators.
abstract: Cryogenic sapphire oscillators (CSO) developed at the University of Western Australia (UWA) have now been in operation around the world continuously for many years. Such oscillators, due to their excellent spectral purity are essential for interrogating atomic frequency standards at the limit of quantum projection noise; otherwise aliasing effects will dominate the frequency stability due to the periodic sampling between successive interrogations of the atomic transition. Other applications, which have attracted attention in recent years, include tests on fundamental principles of physics, such as tests of Lorentz invariance. This paper reports on the long-term operation and performance of such oscillators. We compare the long-term drift of some different CSOs. The drift rates turn out to be linear over many years and in the same direction. However, the magnitude seems to vary by more than one order of magnitude between the oscillators, ranging from 10(14) per day to a few parts in 10(13) per day.
authors.affiliation: Frequency Standards and Metrology Group, School of Physics, University of Western Australia, Crawley, WA 6009, Australia.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Tobar
authors.forename: Eugene N
authors.initials: EN
authors.lastname: Ivanov
authors.forename: Clayton R
authors.initials: CR
authors.lastname: Locke
authors.forename: Paul L
authors.initials: PL
authors.lastname: Stanwix
authors.forename: John G
authors.initials: JG
authors.lastname: Hartnett
authors.forename: Andre N
authors.initials: AN
authors.lastname: Luiten
authors.forename: Richard B
authors.initials: RB
authors.lastname: Warrington
authors.forename: Peter T H
authors.initials: PT
authors.lastname: Fisk
authors.forename: Malcolm A
authors.initials: MA
authors.lastname: Lawn
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Wouters
authors.forename: Sebastien
authors.initials: S
authors.lastname: Bize
authors.forename: Giorgio
authors.initials: G
authors.lastname: Santarelli
authors.forename: Peter
authors.initials: P
authors.lastname: Wolf
authors.forename: Andre
authors.initials: A
authors.lastname: Clairon
authors.forename: Philippe
authors.initials: P
authors.lastname: Guillemot
mesh_terms: D000537:Aluminum Oxide; D003080:Cold Temperature; D004563:Electrochemistry / Q000295:instrumentation*; D004581:Electronics / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis
chemical_list: D000537:Aluminum Oxide