Friday, July 21, 2006

  The measurements of the bucking coil have used
a polarity convention in which positive current gives
bucking, i. e. positive current gives a field in the
negative z direction.
  Today, Dave Dowell and I switched the polarity stickers
on the bucking coil to conform to the traveller.  Now,
positive current in the bucking coil gives a field in the
positive z direction.  This means, that in order to buck
the field at the cathode, one must use negative current.
The measurement data has not been changed.  The bucking
currents in the data are now the magnitudes of currents
required to buck the field.  The field must be in the -z
direction.  This means a negative current must be used
with the new convention.

Zack Wolf