Repair of R-HRS EDTM

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User name R. Michaels

Log entry time 19:16:29 on July 28, 2009

Entry number 282674

keyword=Repair of R-HRS EDTM

The R-HRS EDTM system had two diseases -- large intrinsic offset of
one module and the inability to change prescale factors. It was
speculated in the last beam time (lots of halogs about this) that the
problem went with the slot, not the module. Turned out to be right.
Moving to slot 11 cured everything. The intrinsic time offset is just
the short delay cable between the modules, and this is taken out in
programming. The prescale factor has the following approx. calibration
(measured with a scaler, and this is the aggregate rate, each channel
gets ~1/8 this rate):

Prescale ..... Total rate

400 ............. 188 Hz
4000 ............ 18.8
4 ............... 18.8 kHz
100 ............. 750.
10 .............. 7500.
10000 ........... ~7 Hz

The L-HRS system should be ready to go also, but I need to check with
a scope when there is access. Detector stacks are out.

A copy of this log entry has been emailed to: xiachao,rsubedi,rom