Speaker
Description
Summary
The requirement of a device emulating the arrival of particles
on a particle
detector is apparent in the construction phase of the
corresponding readout
electronics and DAQ system.
The emulator produces randomly generated trigger pulses
with time intervals
following an exponential distribution with programmable
mean between 1 KHz and 1
MHz (trigger rate). The source of randomness is the
avalanche effect on a
transistor emitter-base diode biased by a digitally controlled
voltage source.
Therefore, by changing the diode biasing the desirable
trigger rate is obtained.
The output of the random generator is treated by a digital
processing circuitry
implemented in an FPGA.
The digital processing includes:
• emulation of experiment specific features e.g. the
arrangement of the LHC
bunches during the LHC operation cycle,
• trigger specific rules e.g. maximum consecutive
triggers with minimum
arrival times.
Burst of 1000 random triggers are recorded and can be
played back. In addition to
the random triggers, the system also supports fully
programmable trigger generation
in order to test other distributions. When working as a
stand alone trigger
generator, the system is controlled by a standard pc via the
USB interface.
The system has been extensively evaluated. The
output of the true random
generator has been verified using the NIST battery of tests
for random number
generators. Finally, the system has been calibrated in
respect to the trigger rate.
