Main INDEX
Monthly INDEX
PREV
NEXT
User name R. Michaels
Log entry time 12:35:27 on October27,2000
Entry number 51054
Followups:
keyword=re: trigger for reversed polarity
There is a "theorem" that the trigger supervisor must be on
the spectrometer which has the slowest particles (but it doesn't
matter if the time difference is less than ~25 nsec). So, for
reversed polarity, the trigger doesn't work well unless we move
a bunch of cables. Anyway, the following MIGHT work (at
least to obtain T5). All this on adaqh2:
Compute the delay of the protons. From adaqh2 type "hdelay p 0.88"
to compute the time in nsec.
Go to the right directory, typing "gotrigger"
Start XTrigMang.
Select Right spectrometer
Select trigR_delay3
Enter channel # and set time (the units of set time are 8 nsec per set number,
e.g. a setting of 5 = 40 nsec.)
Don't forget: Press "set" to read in, then "down" to download to crate.
And here are the relevant channels, remember channel # start at 0
Affecting the R-arm trig delay: channels 4,5,6
Affecting the R-arm delay to its own retiming: 10,11,12,13
The R-arm delay + R-delay-retime must add to a constant.
So, if the L-arm is now much slower, you need to add delay
to R-arm to wait. Example
P_L = 0.86 (protons), R-arm are relativistic electrons
adaqh2> hdelay p 0.86
delay = 40.777640 nsec for a proton
Ok, first run 'trigsetup' with 'infinite' momentum (4 GeV). Then
in trigR_delay3, add 5 units to channel 4-6 (NOTE: max is 15 units
on any one channel, you may have to distribute among channels).
Then, subtract 5 units in the channel range 10-13.
And hope it works (I didn't anticipate this request).