Aug 28, 2003, by Dave Mack
These are the links for the beam energy and various kinematic offsets:
1. Preliminary beam energy measurements (by Mark Jones):
4.2 GeV,
5.2 GeV,
3.8 GeV,
4.7 GeV
The energy measurements are called preliminary because the superharp information has not yet
been incorporated.
2. Preliminary e+p offset determinations:
i. offline analysis of single arm measurements (by Tanja Horn)
FpiII HMS runs
The effects of radiation and the W vs xpfp correlation have been taken into account. There are
systematic problems at small HMS angles (ie, where we take all our production data!). We still need
residuals versus HMS momentum and HMS delta. The previously seen high values of W at 5.2 GeV were
attributed to a vertical beam position error for which a preliminary correction has been made using
only 3H00C BPM information.
Tanja's online single arm measurements
(superseded)
4.2 GeV,
5.2 GeV,
3.8 GeV,
4.7 GeV
To summarize, these results provided a rough online confirmation of the beam energy, HMS momentum, and
HMS scattering angle. However, one or two settings have problems at 4.2 GeV, the beam energy or HMS momentum
is systematically incorrect at 5.2 GeV, and a few settings have serious problems at 3.7 GeV. Happily, 4.7 GeV
looks great. I don't know if these runs were all replayed with good time-to-distance maps. The reported
W vs xpfp correlation in the HMS presumably means that the delta offset will be goofy for delta .neq. 0. (This is
not obvious, but due to the correlation of xpfp with delta.)
ii. coincidence measurements (aka HEEPCHECK)
Preliminary PmOOP analysis (by Chuncheng Xu)
updated 9/10/030
Preliminary HEEPcheck analysis (by Chuncheng Xu)
Next step: taking into account radiative shifts and checking that the beam spot didn't move
significantly. If all these data are near delta=0, then the delta dependence on hsxpfp should
be irrelevent.
List of HEEPcheck runs (by Chuncheng Xu)
When the residuals are at the 1 MeV level, the final step in the offset determinations will be
to use simc to determine the apparent offsets caused trivially by electron radiation. As shown
in the figure, electron radiation causes the HEEPcheck variables W, Emiss, Pmpar, and Pmperp to
have tails which can potentially bias the fitted centroid at the 1 MeV level. The only variable
without such a bias appears to be PmOOP.
Plot showing radiative tails of heepcheck variables
3. SOS Saturation Information (by Dave Mack)
Using the code from the engine's central field correction for the SOS, I made a plot for comparison to
Figure 4.7 of Jochen's thesis. The agreement is good though that doesn't make it correct. If the saturation
correction is enabled and SOS momentum offsets are determined, at least we'll have some hope of understanding
what it means.
Plot of SOS saturation correction in engine as of September 9, 2003
Data for SOS saturation correction plot
4. standard.kinematics
