Upload
diana-casey
View
222
Download
1
Embed Size (px)
Citation preview
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
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
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
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)
Integration of the NEUCAL prototype with a 16 X0 tungsten calorimeter (25 July 2009)
NEUCALNEUCAL
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)
Digitalization of one electron event
ScintillatorsScintillators 3He tubes3He tubes
11 22
44 55
33
DOWNSTREAMDOWNSTREAM
UPSTREAMUPSTREAM Trigger signalsTrigger signals
All signals rise at t = 0 (prompt shower secondaries)
Digitalization of pion events (1)
ScintillatorsScintillators 3He tubes3He tubes
11 22
44 55
33
DOWNSTREAMDOWNSTREAM
UPSTREAMUPSTREAM Trigger signalsTrigger signals
t ~34 s
t ~100 s
Digitalization of pion events (2)
ScintillatorsScintillators 3He tubes3He tubes
11 22
44 55
33
DOWNSTREAMDOWNSTREAM
UPSTREAMUPSTREAM Trigger signalsTrigger signals
t ~28.5s t ~46.8s
t ~250s
Digitalization of pion events (3)
ScintillatorsScintillators 3He tubes3He tubes
11 22
44 55
33
DOWNSTREAMDOWNSTREAM
UPSTREAMUPSTREAM Trigger signalsTrigger signals
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