Speaker
Dr
Isaac Vasserman
(Argonne National Laboratory)
Description
There have been upgrades to all subsystems of the insertion device magnetic
measurement system: the Hall probe, the moving coil, the stretched rotating coil,
and the stretched single-wire system. The noise levels and reproducibility of
measurements have been improved considerably so that no statistics are needed in
integral measurements. Only one measurement is enough and two scans are made
usually just for confirmation. Issues with zero drifts are avoided by the use of
numerical integration instead of analog integrators. A previous limitation in Hall
probe measurement accuracy arose from errors in the position measurement;
synchronization with the encoder has been improved so that skipped and double-
counted points are recognized and corrected. The present reproducibility in the
rotating stretched-coil field integral measurements is ~0.1 G-cm for a 4-m-long
coil. The Hall probe reproducibility, as represented by the RMS error in the
difference between two consecutive scans, is ~0.7 G for a peak field of 0.8 T.
*Work supported by the U.S. Department of Energy Office of Basic Energy Science, ,
under contract No. W-31-109-ENG-38.
Primary author
Dr
Isaac Vasserman
(Argonne National Laboratory)
Co-author
Dr
Joseph Z. Xu
(Argonne National Laboratory)
