Document type:
Title:
Revision date:
Revision:
User's Manual (MUT)
Mod. V812 16 Channel Constant Fraction Discriminator
20/04/2009
4
NPO:
Filename:
Number of pages:
Page:
00101/97:V812x.MUTx/04 V812_REV4.DOC
23
21
4.9. Setting the Dead Time
It is possible via VME to set a Dead Time value in common to a group of 8 channels. This
prevents the triggering of the discriminator by unwanted pulses occurring within the Dead Time
programmed value. It can be set by a VME access at (Base A %44) for channels 0 to 7
and at (Base A %46) for channels 8 to 15 (set values: 0 to 255). The set value
corresponds to the Dead Time as follows: 255 leads to a 2
μ
s value, 0 leads to a 150 ns value
with a non-linear interpolation for intermediate values.
N.B.: The actual Dead Time is equal to the greater between Output Width and Dead Time
set
4.10. Current Sum signal
The front panel also houses the
Current Sum (
Σ
)
output connector which provides a current
proportional to the input signal multiplicity, i.e. to the number of channels over threshold, at a
rate of -1.0 mA per hit (-50 mV per hit into a 50 Ohm load)
±
20%.
Fig. 4.1: Current Sum signal
Note:
The
Σ
output requires a 50 Ohm termination for a correct operation of the
Majority logic.
Channel 1
Channel 3
Channel 2
Current Sum (
Σ
)
time
-1
-3
-2
m A
0
