München 2004 – scientific programme

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Q: Quantenoptik und Photonik

Q 33: Poster Pr
äzisionsmessungen und optische Messtechnik

Q 33.2: Poster

Thursday, March 25, 2004, 14:00–16:00, Schellingstr. 3

Performance and comparison of optically-pumped cesium magnetometers with fT sensitivity — •Stephan Gröger¹, Anatoly S. Pazgalev², and Antoine Weis¹ — ¹Université de Fribourg, Physics Department, Chemin de Musée 3, 1700 Fribourg, Switzerland — ²Ioffe Physical Technical Institute, Russ. Acad. Sc., St. Petersburg, 194021, Russia

A neutron edm experiment is being set up at the new UCN source (SUNS) under construction at Paul-Scherrer-Institute (Switzerland). The control of the 2 µT magnetic field applied to the neutrons is of crucial importance for the control of systematic effects. For this task optically pumped cesium magnetometers (OPM) are foreseen for measuring and stabilizing the magnetic field. In this context we have developed laser-pumped magnetometers with 7 cm diameter Cs vapor bulbs as sensors, operated in the M_x-configuration by phase-locking the frequency of an oscillating magnetic field (7 kHz) to the Cs Larmor frequency. The intrinsic sensitivity is 14 fT/√Hz.

Compared to a broadband pumping source such as a discharge-lamp the use of a laser allows a specific choice of the pumped hyperfine transition providing a higher pumping efficiency, which yields a higher sensitivity as a lamp-pumped magnetometer. On the other hand a lamp is less affected by light-shift effects. A comparison of the performance of state-of-the-art lamp-pumped and laser-pumped OPMs including the study of different operation modes will be presented.