ANTI-2 Test Beam

Paolo Valente on behalf of the LAV team

Test beam objectives

1. Validate final version of front-end electronics plus modifications of voltage divider:a) Time-over-threshold vs. charge calibration curvesb) Efficiency vs. threshold for electrons, hadrons and muons

2. Test new FEE with TELL1 readout

All that on a full, final ANTI ring, and thus also checking:- construction techniques- cabling and connectors- new DB37 signal flanges- new ground feed-through on HV flange

Test beam setup

Read half of the channels:- 16 out of 32 channels for each of the 5 layers (5/10 DB37 connectors)

HV supplied to all 160 ch’s

(Luckily the gain equalization done in Frascati was fine and we had not to change the HV settings)

Signal and HV flanges

Side B

Channel 10

Channel 1 (17, 33, 49, 65)

Side A (powered, but not read-out)

Readout map

Readout configurations

We have used three different configurations:• Phase 1: readout by 5 FE boards as in 2009 test:

– 5×16 input ch’s Threshold 5×16 out LVDS TDC – 5×16 input ch’s 5×16 analog out delays QDC

• Phase 2: insert prototype of final FE board:– 8 input ch’s 2 Thresholds 2×8 out LVDS TDC– 8 input ch’s 2 Analogue 4-fold sum delays QDC

• Phase 3: back to old FE boards – efficiency studies– final FE prototype connected to TELL1 for readout tests

Setup (1)

Trigger:- 2 scintillators (cross) in “front” of the ANTI-2, defining a 6×6 cm2 area (AND)

- 1 scintillator on the “back” generally NOT used as veto, but only for checking longitudinal containment

“front”

“back”

Setup (2)

2 beam Cerenkov counters (TDC & QDC):– Operated at two different pressures to have, in a

given momentum range:• Cerenkov A: threshold between e and m • Cerenkov B: threshold between m and p

Focus at wire chamber + 2m

Cerenkov

Beam scintillator

Trigger scintillators

Setup (3)

Beam

Wire chamber

10 26 42 58 74

9 25 41 57 73

11 27 43 59 75

1228

44 60 76

13 2945 61 77

8 24 40

Most hit crystals map

Layer 1

Layer 2

Layer 3

Layer 4

Layer 5

Scintillators & coincidence

New front-end board(double threshold)

Empty

Online counts (TDC)

TDC hit-map

channel #

# of

hits

Preliminary results: time-over-threshold calibration

Charge vs. ToT

Run 627, Threshold=4 mV Run 638, Threshold=8 mV

ToT (ns)

QD

C (p

C)

Charge vs. ToT

Run 627, Threshold=4 mV Run 638, Threshold=8 mV

Threshold not changed (broken test point)

ToT (ns)

QD

C (p

C)

Charge vs. ToT Run 178

An effect due to geometry?...

58

25 41

11 27 43 59

28

57

…or the usual jump due to threshold crossing?

New FE board

8 channels × thresholds:

Channel 10, 11Channel 26, 27

Channel 41, 42Channel 58Channel 74

Analog sum 1

Analog sum 2

Run 202

Run 178

ToT (ns)

QD

C (p

C)

Old FE boardQDC is fed with individual channel analog signal (channel 41)

New FE boardQDC is fed with 4-fold analog sum (channels 41+42+58+74)In final configuration, this will be the sum of the four crystals in one “banana”

Total charge with ToT vs. QDC

4th order polynomial parametrization of charge vs. ToT curve

Compare charge from QDC with charge from ToT

0.3 GeV run

Preliminary results: muon efficiency

Muon selectionSc

intil

lato

r 2 (

pC)

Scintillator 1 (pC)

+ ask for hit crystal in previous and following layer+ isolation cut (allowed only additional hit in the nearby crystal)

Scin

tilla

tor 2

(pC

)Scintillator 1 (pC)

FE threshold

Black: all eventsRed: with TDC hit

Charge (pC)

Threshold = 8 mV

Make the ratio,Fit the threshold profile

Profiting of the only muon runs…(Lau configuration: 8 GeV hadrons + beam stopper,fully open collimators)

Effici

ency

Charge (pC)

Threshold calibrationTh

resh

old

(pC)

Threshold (mV)

From known threshold, extract mVpC conversion

Muon efficiency

Threshold (mV)

Effici

ency

Layer 5Layer 4Layer 3Layer 2Layer 1

Muon runs

Monte Carlo (K. Massri)

Layer 1 data

Muon runs

Threshold (pC)

Effici

ency

… but a lot of work is needed in order to have a better understanding of data, Just one example: what is the effect of the mis-tagging of the scintillators trigger?

Muon efficiency vs. threshold

Monte Carlo (K. Massri)

Layer 2 data

Muon runs

Threshold (pC)

Effici

ency

… moreover, the horizontal scale depends on the photo-electron to pC conversion factor (and thus on the exact gain)

Muon efficiency vs. threshold

Considerations on efficiency studiesWe should consider that this will not be the way photons will hit

our veto stations

Comparison with Monte Carlo

Fraction of energy in veto station (E0=0.5 GeV) vs. azimuthal and polar angles (and projections)

D. Di Filippo

We have tried to perform an horizontal scan (+10 cm, +20 cm towards the center of the ring) by moving our trigger scintillators, in order to check the impact of the lateral “cracks”.Since we did not move the ANTI-2, one should take into account also the angle.Analysis is ongoing…

Preliminary results: electron selection

Cerenkov countersCe

renk

ov 2

(pC

)

Cerenkov 1 (pC)

Run 656

Electron selection

Total Energy (pC)AllScintillatorsScintillators + Cerenkov

Run 663

0.5 GeV 1 GeV

Electron selection

Total Energy (pC)AllScintillatorsScintillators + Cerenkov

Run 647

2 GeV

Run 548

3.5 GeV

New FE + TELL1 test

- 4 crystals on layer 1 and 4 crystals on layer 2 on opposite hemisphere with respect to beam impact point (only muon halo events) - fed to new FE board- readout by TDCB on TELL1

To do list

• To do: o Data quality: • Selection of good runs, check all channels, hardware

changes, etc.o Time resolutiono Electron efficiency vs. energy:• In order to do this, we have to improve on the tagging

of the incoming particle, e.g. we can ask for a deposit in the crystal in the first

o Linearity, containment vs. impact point, etc.

Conclusions

• All in all, the ANTI-2 test was positive from the point of view of:– Signal and HV flanges modifications– New FE board functionality (both for ToT discriminator and for analog

sum circuit)– Basic test of FE board/TELL1 + TDC board matching

• We collected a lot of useful data (still to be analyzed…):– We had runs at 0.3, 0.5, 1, 1.5, 2, 3, 4, 6, 8 GeV (with steeply

decreasing fraction of electrons/muons+pions) and also dedicated purely muons runs

• We have performed threshold scans and a threshold vs. energy calibration, demonstrating that in a good noise (grounding) situation we can work at a fraction of MIP (1/3 maybe even 1/4)

Useful info

E-logbook

Data repository

Special acknowledgements

In addition to all the members of the LAV team:• Horst Brueker, PS & SPS coordinator• Lau Gatignon, for continuous support with the beam• Antonino Sergi, “special guest” of the entire test, putting his

hands in almost everything• Gianluca Lamanna, Bruno Angelucci, TELL1 gurus