User name Nilanga
Log entry time 18:13:18 on February16,2000
Entry number 34135
keyword=y_tg problemIt seems that the e.y_tg problem that occured after run 2208 is due to a jump in the Electron Q2 magnetic filed by about 1% giving a bad tune.
the magnet current (as measured) remained same while the field changed from 0.899 to 0.9085.
This mainly shows up in y_tg as correlations with y_fp and ph_fp. This is very similar to what we saw in the case of the quad hysterisis problem. Although we can't see it clearly, the momentum resolution must be affected too as it did in the case of hysterisis.
First figure shows y_tg vs. e.y_rot for run 2164 (before the problem occured) while the second it the same plot for run 2227. Projection of this on the y axis is your y_tg !
FIGURE 1
FIGURE 2
