Projet d'Horloge Atomique par Refroidissement d'Atomes en Orbite is an atomic clock based on laser cooled cesium atoms that will be installed on board the International Space Station (ISS) in the frame of the ACES mission. Clocks performances are deeply affected by the stability and homogeneity of the magnetic field seen by the atoms. In the ISS orbit the main magnetic perturbation is the Earth's magnetic field variation. In order to attenuate this fluctuation PHARAO clock uses three concentric Mumetal magnetic shields combined with several coils to improve the field homogeneity. We present our experimental studies on the shields attenuation, the shields hysteresis and the field homogeneity. The attenuation depends on the amplitude of the magnetic field and has an average value of 17000 when the external field is similar to the orbit field (30 microtesla). The magnetic shields have undergone thermal and vibration environment tests required by this space mission. By adjusting the currents in the coils, the magnetic field inhomogeneity will reach a value compatible with the frequency accuracy requirement of 10−16.
Magnetic shielding of the cold atom space clock PHARAO
2013-06-01
1599289 byte
Conference paper
Electronic Resource
English
Magnetic shielding of the cold atom space clock PHARAO
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