A series of tests was started in July 2001 in order to determine the
effects of the Hydrogen cleaning
technique that is used on all our wafers on the electron beam polarization.
This tests involved subsequent cleaning cycles of the same wafer and Mott polarization measurements
after each of cleaning. In order to obtain meaningful results, it is necessary to perform the Mott
measurements at the same location on the wafer after each cleaning. To ensure this, we have to keep the
orientation of the stalk constant when we install it in the test cave gun .
In addition, we ensured a constant stalk orientation in the portable Hydrogen cleaning chamber.