Köln 2004 – scientific programme

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HK: Physik der Hadronen und Kerne

HK 12: Poster Session: Instrumentation and Applications

HK 12.18: Poster

Tuesday, March 9, 2004, 13:30–15:30, Foyer

Magnetic field stabilization by a Helmholtz-like coil configuration — •Henneck R., S. Czekaj, M. Daum, P. Fierlinger, Z. Hochman, M. Kasprzak, K. Kohlik, K. Kirch, M. Kuzniak, G. Kuehne, D. George, A. Pichlmaier, A. Siodmok, A. Szelc, and L. Tanner — PSI

For highly sensitive measurements of the neutron electric dipole moment (EDM) the magnetic field has to be stable on a level below picoTesla. One of several measures we employ to achieve this (apart from passive mu-metal shielding with shaking, resonance frequency stabilization, internal field stabilization, multi-chamber system) is to use an external field coil system which can stabilize the ambient external field at a predefined value. Here we report on the construction and characterization of such a system in the magnetic test facility at PSI. The system actively stabilizes the field along the axis of the EDM experiment by means of 4 coils in a Helmholtz-like configuration. Additional coils serve to compensate for transverse ambient field components. Due to the 4-coil geometry large magnetic suppression factors are expected. Because of the long integration times in the EDM experiment (about 100 s or more) only slow disturbances have to be corrected for. The performance of the system has been measured using static as well as moving magnetic sources and suppression factors in excess of 200 have been observed.