LAV front-end board test
Francesco Gonnella, Mauro Raggi
Photo Veto Working Group
1 April 2014
Francesco Gonnella - Laboratori Nazionali di Frascati
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LAV front-end electronics
LAV electronics channel working principle
to analog sum
LVDS
Low
threshold
Split
Amp 6x
Compare
To TDC
High
threshold
LVDS
Clamp
To TDC
 Split the input signal into two copies: 1 copy to comparator + 1 copy
to analog sums
 Clamp the signal preserving its width, wide dynamical range is
expected (MIP 70 MeV ~ 10 mV, high energy γ ~ 1V)
 Amplify the signal and compare with 2 thresholds
 Each threshold is independently adjustable up to 250 mV
 Produce an LVDS signal and send the signal to the digital read out
board
Francesco Gonnella - Laboratori Nazionali di Frascati
1 April 2014
2
Test setup
 Hardware setup
Hardware layout
x2
x 16
32 ch
32 ch
x 16
TDC
CAEN
V1190B
VME
VME
Bridge
V1718
Linux
PC
GPIB programming
 Software flaw chart
repeat
n times
Repeat
n’ times
repeat
n times
Francesco Gonnella - Laboratori Nazionali di Frascati
1 April 2014
3
Efficiency step-plot
Threshold = 10 dac unit
Threshold = 20 dac unit
Threshold = 30 dac unit
Threshold = 50 dac unit
Threshold = 100 dac unit
Threshold = 350 dac unit
Francesco Gonnella - Laboratori Nazionali di Frascati
1 April 2014
4
Problems in some step-plots
Threshold = 10 dac unit
Threshold = 20 dac unit
Threshold = 30 dac unit
Threshold = 50 dac unit
Threshold = 100 dac unit
Threshold = 350 dac unit
Francesco Gonnella - Laboratori Nazionali di Frascati
1 April 2014
5
Calibration test
 From every step-plot the 95% efficiency value is extrapolated
obtaining a calibration line, like this:
Francesco Gonnella - Laboratori Nazionali di Frascati
1 April 2014
6
Calibration slope
 Slope very stable in “good” channels
 Channel with different slope (i.e. amplification) were discarded
(wrong resistor value)
Francesco Gonnella - Laboratori Nazionali di Frascati
1 April 2014
7
Time resolution
G=3, 26 boards
G=6, 67 boards
Noisy
channels
 Time resolution has improved thanks to low-noise power supply.
Francesco Gonnella - Laboratori Nazionali di Frascati
1 April 2014
8
Threshold offset
G=3, 26 boards
G=6, 67 boards
 Threshold offset are all below 7 mV, below 6 with a smart
choice of high and low threshold
Francesco Gonnella - Laboratori Nazionali di Frascati
1 April 2014
9
Conclusions
 We have successfully tested 67/90 LAV-FEE boards
 Faulty mezzanines and motherboards sent to repair
 65 boards for stations A1-A10 delivered to ECN3 this morning
 The first 8 stations will be equipped and tested with cosmic rays
during the next two weeks
 Tests will make use of the complete NA62 trigger chain with
trigger-primitive generated by LAV itself
Francesco Gonnella - Laboratori Nazionali di Frascati
1 April 2014
10
Thank you for your attention
[email protected]
1 April 2014
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