RUN 90237 SM1 & 2
RUN 90240 SM3 & 4
RUN 90241 SM5 & 6
First a set of two tanks, one each from two different
horizontal planes was chosen and linear distance between the two
tanks and the time of flight to travel the distance by a relativistic
particle was calculated (20-40 nsec).
We set the delay of output 1 of both HP pulsers to the time of
flight while the delay of output 2 was set to 0. Pulse height was set to
-7 Volt and width was 20 nsec for all outputs. Pulse from output 2 is fed
to tank1 and output1 to tank2. (NOTE: usually out1 goes to tank1 and
out2 goes to tank2 but I switched them to make it run faster - tank2
should be set 16 times more frequently and switching relay takes time.
This is all software nothing has been changed to hardware)
Of course the pulser 1 was used to fire LED's on 1_end of the tanks and
pulser 2 to 0_end of the tanks.
While it is called Up going muon calibration we actually fired
LED's in such a way that can simulate both up and down going muons.
This was done by switch delay time of the two output of the pulser
while tank setting was unchanged. So, for each tank combination there
is an equal number of simulated up-going and down-going muons.
At first, pulse rate was 10 Hz and number of pulses at the same
setting was 10 (up-going) + 10 (down-going). This rate was used for
SM1, 2 & 3. Rest of the SM's were done with reduced pulse rate(4 Hz)
and reduced number of pulses: 5 (up-going) + 5 (down-going). This was
because we were afraid the 10 Hz rate was too fast for ERP. Actually,
for SM1/2/3, ERP did not fire with 100% efficiency on the generated LED events.
Basic information for event was written on the borer module.
The bit pattern is as follows:
bit 0 - 2 : caltyp = 6
bit 3 - 9 : tank1(1 - 88) with nodelay
bit 10 - 16 : tank2(1 - 88) delayed
bit 17 : 1 if SM is even (0 for odd)
bit 18 - 23 : Delay (0 - 63 nsec)
We tried all possible combination of tanks in Bottom_and_
Center AND Center_and_Top configuration. Bottom_and_Top was not
considered. Basic info about the tank number and delay time together
with event no is written in MU_TDC_HIST_SMn.TXT
in [scintsoft.calib.led.dev.dev]