The beam leakage from Hall A was only a problem during the
the perpendicular running when Hall A laser was at a wavelength
that produced 35% polarization. During the parallel running 
the Hall A laser wavelength was change since Hall A wanted
highly polarized beam. This is why the leakage measurements ended
on Feb 11. 

Measured leakage current from Hall A with rates in the HMS.

A = rates in HMS with target and Hall C laser on.
B = rates in HMS with target and Hall C laser off.
C = rates in HMS with target and Hall C slit closed

leakage equal = (B-C)/(A-C) .

Ph = pol in Hall C , Pc = pol of hall C beam at injector
                     Pa = pol of Hall A beam at injector



 Ph  = Pc*(Rc/Rt) + Pa(Ra/Rt)  =Pc*[ (Rt-Ra)/Rt + (Pa/Pc)*(Ra/Rt) ]
 
 Ph = Pc*[ 1 - Ra/Rt*[1-(Pa/Pc)] ]  

If Pa/Pc = 0.5 then Ph = Pc*[1-0.5(Ra/Rt)]

With Ra/Rt = 0.02 then Pn = Pc* 0.99 


List of beam leakage measurements
--------------------------------

Date         Leakage percentage       Comment
----         ------------------       ----------
Jan 25 20:02  0%
Jan 27        1.2%                    30uA Hall A
Jan 28 0:00   6.2%
Jan 28 1:00   5%
Jan 28 1:30   0.7%
Jan 28        1.5%                    50uA hall A
Jan 30        3.5% reduced to 1.6%    Reduce leakage current by increasing laser power and
                                   reducing slit size
Feb 1 4:23    4.2% reduced to 2.1%
Feb 2 13.45   1%
Feb 2 16:44   1.7%
Feb 4 10:15   2.1% reduced to 1.6%
Feb 4 17:50   1.5%
Feb 7 9:03    2%
Feb 8 6:07    1.9%
Feb 8 22:57   1.2%
Feb 9 13:00   1.5%
Feb 9 22:00   3.5%
Feb 10 1:14   10%
Feb 10 1:31   1.4%
Feb 10 19:02  .6% 
Feb 11 2:39   <1%
Feb 11 19:38  1%