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Document type:
Title:
User's Manual (MUT)
Mod. V812 16 Channel Constant Fraction Discriminator
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 Address + %44) for channels 0 to 7
and at (Base Address + %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 μs 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%.
Note: The Σ output requires a 50 Ohm termination for a correct operation of the
Majority logic.
Channel 1
Channel 2
Channel 3
Σ
Current Sum (
NPO:
00101/97:V812x.MUTx/04
)
0
-1
-2
-3
m A
Filename:
V812_REV4.DOC
Fig. 4.1: Current Sum signal
Revision date:
Revision:
20/04/2009
4
Number of pages:
23
time
Page:
21
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