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LAV front-end threshold study. Mauro Raggi Francesco Gonnella 5 th February 2013 Photon Veto Working Group Meeting. Outline. Noise studies Inside Wiener crate Outside wiener crate Threshold offset studies Using different gain G=5. Threshold offset fine tuning technique Noise at G=5 - PowerPoint PPT Presentation
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LAV front-end threshold studyMauro RaggiFrancesco Gonnella
5th February 2013
Photon Veto Working Group Meeting
Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy
Outline Noise studies
Inside Wiener crate Outside wiener crate
Threshold offset studies Using different gain G=5. Threshold offset fine tuning technique Noise at G=5
MIP efficiency studies
Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy
Noise tests @ LNF We get two different runs for each test
No signal: all final conditions but pulser is Off Signal: 100mV signal and pulser On
We performed a lot of test: In Crate thr 0 mV nominal In Crate thr 2 mV nominal In Crate thr 5 mV nominal In Crate thr 7 mV nominal
Board moved outside the crate powering it with linear PS We immediately concluded that the situation is improving We did test in the Owen with power from outside
Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy
Noise in WIENER crate 2mV thr
No signal 100mV signal
Rate in Hz extrapolated using the total effective acquired time:Tacq = 3.5E3 * 0.5E-6 * 7 = 1.2E-2sThe noise rate goes to ~Hz if the nominal Thr is higher than 7mV (nominal)
Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy
Noise linear PS 2mV thr
The board has been moved out from the crate to a table and the ±7.5V power is provided by an external linear power supply.
No signal 100mV signal
Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy
Block time resolution examplesOutside crate G=5Inside crate G=3
The uniformity of the time resolution is excellent in the outside crate situation while shows problems due to noise inside the crate.
The noise itself! On top: noise shape
taken from sums outputs
Bottom: output of FEE digital signal after LVDS to NIM converter
Noise frequency 594KHz which seems to match the operating frequency of different low voltage switching regulators
The noise is coming from the wiener power supply.
Suspect improper grounding in the LNF lab. Test at CERN is foreseen
Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy
Thr offset and amplification We changed the the board 26 amplification setting up 16
new mezzanines modified to get gain=5. The thr offset have been measured using both G=3 and G=5
with the same procedure in the Front End Test stand
The values of mean offsets scale in reasonable way: Model needed to compensate for amplification
Threshold linearity scan performed
G=5G=3
Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy
Equalization quality tests Using just the measured values of the offset with LavFeeTest
We equalized at 10 mV DAQ(Thr (95%))= required value – Offset Measured the new thr offset with the usual method
The quality of the equalization is very good s = 0.15 mVThe absolute value has to be corrected for amplification (G=5) 1.43 factor which leads to ~13. mV at the comparator level
Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy
Noise conditions G=5 2mV out
Some extra hits observed in presence of the signal with G=5;No extra activity with pulser Off
Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy
Threshold linearity test G=3
All the thr are linear over the explored range
Lines have almost the same slope: (1.16 ± 0.02)(mV pulser)/(mV DAQ)
0 5 10 15 20 250.00
5.00
10.00
15.00
20.00
25.00
30.00
35.00
f(x) = 1.16702275769746 x + 6.75353949129853R² = 0.99995180493508f(x) = 1.16178982597055 x + 6.36419410977242R² = 0.999952774678281f(x) = 1.16926773761714 x + 5.6715234270415R² = 0.999936709022736
f(x) = 1.15593172690763 x + 8.77838152610442R² = 0.999952409514456
Pulse
hei
ght [
mV]
@ 9
5%
Programmed DAQ value [mV]
Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy
Threshold linearity test G=5
Lines have almost the same slope: (0.70 ± 0.01)(mV pulser)/(mV DAQ)
0 5 10 15 20 250.00
5.00
10.00
15.00
20.00
25.00
f(x) = 0.708447121820616 x + 3.8703641231593R² = 0.999857869758641f(x) = 0.708447121820616 x + 3.8703641231593R² = 0.999857869758641
f(x) = 0.690963855421687 x + 5.1760843373494R² = 0.999782545592171f(x) = 0.683215528781794 x + 3.40375635876841R² = 0.999498139272081
Pulse
hei
ght [
mV]
@ 9
5%
Programmed DAQ value [mV]
Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy
The MIP efficiency measurement
We mounted the LAV FEE026 on the oven and get an acquisition with the following scheme:
We set the thresholds to equalized values using DB Offset values
Using the channel with the single column signal (12-15) we got the efficiency of the 12 equalized blocks at different thresholds More stringent trigger is also used for the analysis
0
1
2
3
4
5
6
7
8
9
10
11
12 13 14 15Trigger
Trigger 12 13 14 15
Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy
Triggers performance
Only trigger column coincidence signal Added the request for at least 1 other block in the column
Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy
MIP efficiency oven triggers
The average MIP efficiency is quite different:
Is that due to different muon sample or to noisy oven triggers?
1 more blockOven Trg
Spurious effect due to trigger request and inefficiency in last channel
Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy
Block time resolution
Resolution order 2ns with no slewing correction and unknown trigger time resolution included!
Strange peaks in the distribution.
s ~ 0.5ns/√E
Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy
Leading and leading-trailing EffLeading and trailingLeading only
The leading and trailing difference seems not so big as we could expect! Investigating…
5mV 10mV
Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy
Threshold scan results: 1 more block in the trigger
Thr = 5mV
Thr = 10mV
Thr = 7.5mV
Both boards thr and oven equalization look reasonably good for low thrsSecond order fine tuning can be obtained using HV or thr adjustments
Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy
The ToT puzzle
Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy
Conclusions Status:
We discovered the origin of noise (Wiener PS) The quality of equalization procedure seems good We obtained a first estimate of muon efficiency to
be ~90% at 5mV thr with G=5 in the board. First look at time resolution seems Ok.
Things to do: Check the effect of oven extra cables on signal shape and
efficiency Finish trigger optimization (time cuts) Try to further increase the amplification G=6 G=9? Fix an amplification value on the basis of g data spectrum (data
and MC)
Thank you for your attention