User name gilman
Log entry time 03:01:50 on October 30,1999
Entry number 29330
keyword=time needed at 1.95 GeV
I calculated the event rates with longer replays of our current 1.95 GeV
data. I find that the rates are 20 k events / Coulomb for gamma d,
7 k evt / C for e d, and 2.4 k evt / C for gamma p, leading to a need
for 13 C total charge to get an error of 0.05, including a 5% effect
for the (simple dipole) spin transport, assuming an analyzing power
of 0.22 (should be good to ~5%).
Note 9 C would get us a 0.06 uncertainty, while 6.6 C gets us 0.07.
The charge fractions work out to be the same as Krishni and I had
calculated earlier, with poorer statistics replays.
We take 0.11 C / hour at 30 microamps and 100% efficiency,
so we need 4.9 100-% efficient days in our scheduled 7 days at this
We also have ~ 1 day of systematics checks I have in mind,
plus we have considered the desirability of "2 days" for gamma p
measurements at this energy.
It appears clear everything cannot be done.