title: High Stability Comparison of Atomic Fountains using two Different Cryogenic Oscillators.
abstract: We present a detailed characterization of two atomic clock interrogation systems based on two different cryogenic sapphire oscillators operated simultaneously. We use them as references for two accurate fountain clock frequency standards participating in international atomic time and operating both at the quantum projection noise frequency limit. The two fountain comparison down to a few 10􀀀16 over 28 days demonstrates the potential of a cryocooled oscillator to replace a He refilled cryogenic oscillator.
authors.forename: Michel
authors.initials: M
authors.lastname: Abgrall
authors.forename: Jocelyne
authors.initials: J
authors.lastname: Guena
authors.forename: Michel
authors.initials: M
authors.lastname: Lours
authors.forename: Giorgio
authors.initials: G
authors.lastname: Santarelli
authors.forename: Michael
authors.initials: M
authors.lastname: Tobar
authors.forename: Sebastien
authors.initials: S
authors.lastname: Bize
authors.forename: Serge
authors.initials: S
authors.lastname: Grop
authors.forename: Benoit
authors.initials: B
authors.lastname: Dubois
authors.forename: Christophe
authors.initials: C
authors.lastname: Fluhr
authors.forename: Vincent
authors.initials: V
authors.lastname: Giordano