Polarity check for BXHS4 on June 2, 2020 by Scott Anderson
Field was measured at z center with the hall probe tip pushed up against the side of the dipole near the gap.  The gap is completely filled by the vacuum chamber.
Main at +6 amps, Field measured =  -0.355 Tesla, negative polarity
Trim at +6 amps, Field measured =  -0.0169 Tesla, negative polarity