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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

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lav front end threshold study

LAV front-end threshold study

Mauro RaggiFrancesco Gonnella 5thFebruary 2013

Photon Veto Working Group Meeting

outline
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
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 Cratethr0 mV nominal
    • In Crate thr2 mV nominal
    • In Cratethr5 mV nominal
    • In Cratethr 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
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-2s

The 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
Noise linear PS 2mV thr

No signal

100mV signal

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.

Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy

block time resolution examples
Block time resolution examples

Outside crate G=5

Insidecrate G=3

The uniformity of the time resolution is excellent in the outside crate situation while shows problems due to noise inside the crate.

Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy

the noise itself
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
thr offset and amplification
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=5

G=3

Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy

equalization quality tests
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 mV

The 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
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
Thresholdlinearity test G=3
  • All the thr are linear over the exploredrange
  • Lines have almost the same slope: (1.16 ± 0.02)(mV pulser)/(mV DAQ)

Pulse height [mV] @ 95%

Programmed DAQ value [mV]

Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy

threshold linearity test g 5
Thresholdlinearity test G=5
  • Lines have almost the same slope: (0.70 ± 0.01)(mV pulser)/(mV DAQ)

Pulse height [mV] @ 95%

Programmed DAQ value [mV]

Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy

the mip efficiency measurement
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

Trigger

15

12

13

14

9

6

0

3

10

4

7

1

11

5

2

8

Trigger

15

12

13

14

Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy

triggers performance
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 o ven triggers
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 block

Oven 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
Block time resolution

Strange peaks in the distribution.

Resolution order 2ns with no slewing correction and unknown trigger time resolution included!

s ~ 0.5ns/√E

Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy

leading and leading trailing eff
Leading and leading-trailing Eff

Leading and trailing

Leading only

10mV

5mV

The leading and trailing difference seems not so big as we could expect! Investigating…

Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy

threshold scan results 1 more b lock in the trigger
Threshold scan results:1 more block in the trigger

Thr = 5mV

Thr = 7.5mV

Thr = 10mV

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
The ToT puzzle

Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy

conclusions
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 tobe ~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)

Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy