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User name R. Michaels
Log entry time 10:18:01 on May 2,2010
Entry number 320585
keyword=raster/Pb tests, part 3, integ. time scan08:48 .... Remove raster synch.
Safe Procedure is: turn off beam, change synch, check scope in
middle room (raster ok ?), go to 2 uA, check spot++, ramp to 50 uA.
Now we will do a series of short runs with different
integration time using Greenmonster in between runs.
The helicity control board remains
at Mode = Free Clock. Helicity Pattern = Quartet.
T_settle 100 usec, T_stable = 8.23 msec, Reporting Delay 8 windows.
Note: for 25 kHz expect to get 182 raster cycles in 7.28 msec
which is for integ = 2912 units. Since the integral of a sawtooth
over an integral number of periods is zero, one might expect a
minimum noise there if the raster frequency is stable.
Raster synch is off.
Run ...... Integ Time ..... Det_All Width
3392 ..... 2920 ..... 538.5 ppm (was 510 ppm earlier)
3393 ..... 2918 ..... 536.8
3394 ..... 2916 ..... 534.7
3395 ..... 2914 ..... 534.9
3396 ..... 2912 ..... 541.0
3397 ..... 2910 ..... 535.5
3398 ..... 2908 ..... 541.0
3399 ..... 2906 ..... 548.3
3400 ..... 2904 ..... 538.7
3401 ..... 2902 ..... 539.5
Repeatability checks:
Run 3402 ... junk (CODA problems)
3403 ..... 2912 ..... 560 .... beam trip during this
3404 ..... 2920 ..... 570.5
Seems to be some drift and/or lack of reproducibility
in the det_all width. It could also be that the beam
trips are not handled correctly here, though the beam
was mostly stable. The structure of the scan (online
result) is not very interesting (fig 1).
FIGURE 1
