[G8b_run] g8 meeting this week

[Brian Vernarsky]

Hi all, I just checked on the thrown and reconstructed momenta for the
proton and found that the distribution is in fact quite different,
with the reconstructed momenta being thrown way up towards higher
values.  This does seem to indicate a problem with the magnetic field,
but I'm not sure where the problem is creeping in.  In my ffread card,
which goes to gsim, I set the MAGSCALE to 0.4995, which is very close
to the value from g11 of 0.4974, which makes sense because they had
similar field settings.  For the reconstruction, i.e. the g8b.tcl
file, I have the line "set torus_current      1930;" as I believe that
the current was either 1928 or 1930 for the runs (a difference of 2A
should not make a difference anyway).  These are the values that I
believe are correct and they seem to have been read into the programs
just fine as the output confirms those values.

I am right now recooking the values with the MAGSCALE in the ffread
card changed to 0.25, but not changing the torus current, to see if
that has any effect.  Based on what I see it appears that the gsim
value was too large with respect to the reconstruction value.  But the
number is purely speculative on my part, I just want to see if there
is a change.  If anyone can tell me that 0.4995 is the wrong value and
what the correct one is please let me know.  Thanks for the idea.

Cheers,

Brian