Two-cascade magnetic field stabilizer on an installation for the measurement of the neutron electric dipole moment

Abstract

Abstract A two-cascade magnetic field stabilizer for apparatus for the measurement of the neutron electric dipole moment (EDM) using ultracold neutrons was constructed and tested. Quantum cesium magnetometers (QCM) employing optical pumping and placed inside a multilayer magnetic screen were used as the magnetic field sensors. A static stabilization coefficient of 4 × 10 5 in the presence of magnetic noise of amplitude up to 50 nT was obtained using QCM employing the S z -signal in the inner and outer cascades, their transfer ratios being 300 and 600, respectively. The mean square amplitude of the operating magnetic field fluctuations was 0.1 pT in the interval 10 −4 − 10 −2 Hz. Stabilization over a wider frequency band was obtained using QCM of the S z -type in the inner cascade and of the S x -type in the outer one. In particular, the mean square amplitude of the magnetic field fluctuations in the interval 0.1–1 Hz and 1–10 Hz were 1 pT and 15 pT, respectively.