User name gueye
Log entry time 23:59:41 on July 31,1999
Entry number 14967
Followups:
keyword=beam stability on targetWhile waiting for beam, I have analyzed the 5 last good H2 runs (25905 to 25909) and look at the beam position, angle and dP/P0 on the target (see figures below). These plots include the last girder survey offsets.
* Left picture: position and angle stability
Compares EPICS and ADC values projected on the target from H00A/B/C. The error bars reflect the widening of the distributions.
1- One can clearly see the +/-1 (in X) versus +/-0.5 (in Y) which is the assymetric raster size on the target in the ADC data points but not in the EPICS ones; due to the sampling of the data.
2- EPICS and ADC average values are in very good agreement (beside the run 25906). They both show the same trend within about 200um and 0.5mrad.
3- The data seem to show also an offset of about -0.5 at the target when we ask for (0;-1.5) at H00C. This should be confirmed or infirmed with the offline analysis if additional calibration offsets (from ??) are not sufficient.
* Right picture: energy stability
This fluctuation in energy assumes X/Y readings from 5 BPMs in the arc (07,08,10,12 and 17) and uses the Hall C optic setting (matrix elements).
1- Things look more or less stable within 0.3x10^-3.
2- So a displacement of about 0.5mm corresponds to about 0.5x10^-3 in energy spread
3- The "jump" between run 25905 and 25906 seems to corresponds to the "jump" observed on the 3C12 X-position from hclog #14949 (from E. Rollinde) grabed during this period.
FIGURE 1
FIGURE 2
