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We present the realisation of a compact and high-performance Rubidium atomic frequency standard under development for space applications. The clock comprises a compact frequency-stabilised diode laser head for optical pumping of a lamp-removed industrial Rb clock module, in order to exploit the advantages of laser optical pumping for optimised short- term stability. We obtain typical signal contrasts around 20%, resulting in an estimated signal-to-noise limit for the short- term stability of about 1middot10 -12 tau -1/2 . Modification of the buffer- gas filling in the clock resonance cell allows to reduce instabilities arising from the AC Stark effect and temperature variations, that limit the clock stability on longer timescales. The clock stability of the realised demonstrator breadboard was measured to be better than 4middot10 -12 tau -1/2 up to 10 4 seconds, already meeting the specifications for the GALILEO Rb clocks. Further optimisation should allow the realisation of a laser-pumped Rb clock reaching 3middot10 -13 tau -1/2 in a compact device (

In this article we report on the first use of degenerate Raman sideband cooling for the collimation of a continuous beam of cold cesium atoms in a fountain geometry. Using this cooling technique we have reduced the atomic beam transverse temperature from 60 K to 1.6 K in a few milliseconds. We present experimental results and future directions that we will investigate.

The availability of frequency stabilised laser sources is essential for the realisation of laser-pumped atomic clocks and other applications. Here we present a comparison of two simple spectroscopic schemes for laser stabilisation to the Rb D2 line transitions, based on linear (Doppler-broadened) and non-linear (saturated absorption) spectroscopy in thermal vapour cells, covering time scales up to 105 seconds. We measured short-term stabilities of 2.10-11 τ-1/2 and 2.10-12 τ-1/2 up to 1.10-10 seconds and long-term stabilities at one day around 1.10-10 and 2.10-12 for the Doppler and sub-Doppler scheme, respectively. From a drift analysis of different experimental parameters we find the frequency stability beyond 104 seconds to be limited essentially by variations of the reference cell temperature for both schemes, and estimate limits around 9.10-12 and 2.10-12 for improved experimental realisations. The performance and simplicity of both stabilisation schemes studied makes them interesting for applications in compact atomic clocks and other precision instruments.