Preliminary study of electron/hadron discrimination with the NEUCAL detector.

Preliminary study of electron/hadron discrimination with the NEUCAL

detector

The NEUCAL working group

O. Adriani1,2, L. Bonechi1,2, M. Bongi2, S. Bottai2,M. Calamai4,2, G. Castellini3, R. D’Alessandro1,2,

M. Grandi2, P. Papini2,S. Ricciarini2, G. Sguazzoni2, G. Sorichetti1, P. Sona1,2,

P. Spillantini1,2, E. Vannuccini2, A. Viciani2

1) University of Florence2) INFN Section of Florence3) IFAC – CNR, Florence4) University of Siena

New idea in NEUCAL:• Study of the moderation phase using an active moderator• Standard plastic scintillators are rich in hydrogen and then suitable as

moderators (Eljen EJ-230 [CH2CH(C6H4CH3)]n )

• Detection of:– signals due to neutron elastic/inelastic scattering– signals due to absorption of neutrons by

3He (proportional tubes)

Detection of neutrons produced inside the calorimeter: the NEUCAL concept

PAMELA:• Moderation of neutrons by means of passive moderator (polyethylene layers)• 3He proportional tubes to absorb thermal neutrons and detect signals due to

the ionization of products inside gasn + 3He 3H + p (Q = 0.764 MeV)

SCINTPMT orSi-PMT

3He tube

n

Few details and results• First results based on FLUKA, now implementing also

GEANT4 simulation• Detector geometry has been dimensioned for application

together with a 30 X0 calorimeter (CALET experiment)– NEUCAL is placed downstream a 30 X0 deep homogeneous BGO

calorimeter11

scintillator layers

3He Tubes (1 cm diam.)

30 X0

NEUCAL

BGOtiles

11 cm of plastic scintillators

FLUKA based simulationDegree Thesis byG. Sorichetti

Expected performance (comparison FLUKA/GEANT4)FLUKA simulated energy release inside one scintillator layer

See also: S.Bottai et al., at Frontier Detector for Frontier Physics, La Biodola (Elba), 24-30 May 2009

1 MeV neutrons

10 MeV neutrons

EN

TR

IES

EN

TR

IES

3He Tubes

Distribution of number of neutronsin real e-h showers

400 GeV electrons400 GeV electrons1 TeV protons1 TeV protons

Note: energy release inside the simulated BGO calorimeter is almost the same for 1TeV protons and 400 GeV electrons.

FLUKA FLUKA

Scatter plot: arrival time vs neutron energyAlmost all neutrons exit from the calorimeter within a few microseconds, but thermalization inside neucal can take hundreds microseconds

Outgoing neutron energy Log (E(GeV)/1GeV)

Arr

iva

l tim

e (s

eco

nd

s)

1 G

eV

1 M

eV

100 ns

1 s

1 ke

V

10 ns

The prototype detector

Production of scintillators

One side covered with aluminized tape

Scintillator material:Eljen Technology, type EJ-230 (PVT, equivalent to BC-408)

Light guides: simple plexiglas

Production of prototype detecting modules

Optical grease: Saint Gobain BC-630Saint Gobain BC-630

PMT Hamamatsu Hamamatsu

R5946R5946

Production of the first module

3He proportional counter tube: Canberra 12NH25/1Canberra 12NH25/1

1 cm diameter1 cm diameter

Prototype assembly3x3 matrix of scintillator modules with 5 3He proportional counter tubes integrated

1 cm diameter3He tubes

scintillatorlight guide

PMT

Digitalization electronics

CAEN V1731 boardCAEN V1731 board VME standard 8 ch, 500MS/s 8 bit ADC 2MB/ch memory (few ms digitization) 16 ns jitter On-board data compression (Zero Suppression Encoding)

CAEN V1720 boardCAEN V1720 board VME standard 8 ch, 250MS/s 12 bit ADC 2MB/ch memory (few ms digitization) 32 ns jitter On-board data compression (Zero Suppression Encoding)

Test beam at CERN SPS (August 2009)

Integration of the NEUCAL prototype with a 16 X0 tungsten calorimeter (25 July 2009)

NEUCALNEUCAL

CALORIMETER

CALORIMETER

Beam test details

• CERN SPSCERN SPS, line H4H4 (one week test)• Beam type – energy - # of events:

– PionsPions 350 GeV ( 230000 events)– electronselectrons 100 GeV ( 240000 events)– electronselectrons 150 GeV ( 50000 events)– muonsmuons 150 GeV (130000 events)

• Data collected in different configurations– scan of detector (beam impact point)– different working parameters

• PMTs and tubes voltages• Digitizer boards parameters (thresholds, data compression…)

• Next slides report a comparison of data with GEANT4 simul. for electron and pion events taken in the following configurations:

Detectors’ configuration

ELECTRON

beam

PION

beam

Total thickness upstream NEUCAL: 16 X0

Total thickness upstream NEUCAL: (16+13) X0

NEU

CAL

16 X0

WCALO

NEU

CAL

16 X0

WCALO

9 X9 X 00

PbPb2.

25 X

2.25

X 00Pb

WO

PbW

O 4`4`

30

• Digitalization of scint. output for a long time interval (1ms)• Look for signals which are not in time with other signals on

other channels:– Avoid the prompt signals due to charged particles coming directly from the shower– Avoid single charged particles giving signals on more then one scintillator (non interacting

hadrons entering the detector

How to find neutron signals?

Trigger

PromptsignalScint.

A

Particlesignal

t=0 t=1ms

Promptsignal

t10us

Scint.

B

Particlesignal

?time

time

Digitalization of one muon event

ScintillatorsScintillators 3He tubes3He tubes

11 22

44 55

33

DOWNSTREAMDOWNSTREAM

UPSTREAMUPSTREAM Trigger signalsTrigger signals

t = 0

t ~700ns

Bounces are due to additional filters on the digitizer inputs to solve a problem of firmware (loss of fast signals)

Filter

Digitalization of one electron event


11 22

44 55

33



All signals rise at t = 0 (prompt shower secondaries)

Digitalization of pion events (1)


11 22

44 55

33



t ~34 s

t ~100 s



11 22

44 55

33



t ~28.5s t ~46.8s

t ~250s



11 22

44 55

33



t ~14.6s t ~170s

t ~12.6s

t ~250s

First preliminary comparison data/MC

33000 events- “single” signals- one single central PMT

GEANT4

dataInstrumental effect

?Spurious particles

ARRIVAL TIME

100 GeV ELECTRONS

Specific MC to take into account the meterial in front of NEUCAL

First preliminary comparison data/MC

75000 events- “single” signals- one single central PMT

GEANT4

data

Spurious particles?

ARRIVAL TIME

350 GeV PIONS

Comparison data/MC: signal energy distribution

33000 ELECTRON events

75000 PION events

GEANT4

GEANT4

PRELIMINARY

PRELIMINARY

Comparison data/MC: time distribution

33000 ELECTRON events

75000 PION eventsGEANT4

GEANT4

PRELIMINARY

Test at NTOF facility

Proton beam

Target

~ 200 meters

Neucal

Very intense p beam (20 GeV, 1012 p per spill)…But with very short spill (5 ns)…And very small duty cycle (5 ns/few ms)Neutrons are produced in the target with different energiesNeutrons travel along the 200 m lineThe energy of the neutron is inferred from the arrival time on the Neucal detector

2 weeks at end of OctoberMany thanks to the NTOF collaboration!!!!!

Neutrons

Signals on scintillators

Signals on 3He

Basic Idea

• By knowing the neutron spectrum (both in shape and absolute normalization) we can measure the single neutron efficiency as function of the neutron energy

• Analysis is complex!!!!!!!!!

Preliminary study of electron/hadron discrimination with the NEUCAL detector.

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