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Initial Operation of 46 kg Fermi Chopper for BRISP Instrument at ILL

In close cooperation with Philipps-Universität Marburg, a Fermi chopper was developed, constructed and tested for neutron scattering experiments at the Institut Laue-Langevin (ILL) in Grenoble (France).

The Faculty of Chemistry at Philipps-Universität Marburg operates the BRISP time-of-flight spectrometer at ILL together with the Italian National Research Council (CNR). The team consisting of German and Italian scientists developed and constructed the Fermi rotor weighing a total of 46 kg and the Fermi package for selecting the neutrons.
ZAT contributed the magnetic bearing system, the high-precision drive system and the control system for the chopper, and also assembled and tested the overall system.
With the magnetic bearing and drive systems from Jülich, the chopper can be operated in a vacuum of less than 10-1 mbar and at a maximum rotational frequency of 21,000 min-1, with a phase stability (repeatability of rotations) above 0.05°.

The installation and initial operation of the chopper system successfully tested at Jülich took place at ILL in mid-June 2011.

Engineering design of the horizontal Fermi chopper for BRISPEngineering design of the horizontal Fermi chopper for BRISP
Copyright: Prof. Dr. Wolf-Christian Pilgrim, Philipps-Universität Marburg

BRISP chopper in the test facility at ZATBRISP chopper in the test facility at ZAT

Installed BRISP chopper connected to the neutron guideInstalled BRISP chopper connected to the neutron guide

Positioning the shielding coverPositioning the shielding cover