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Multi Pixel Photon Counters (MPPC) and Scintillating Fibers (Sci-Fi) as a trigger system for the AMADEUS experiment. Alessandro Scordo (L.N.F.) (in behalf of AMADEUS experiment) 23° Indian-Summer School of Physics & 6° HADES Summer School 2011. Contents . - PowerPoint PPT Presentation
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Multi Pixel Photon Counters (MPPC) and Scintillating Fibers (Sci-Fi)
as a trigger system for the AMADEUS experiment
Alessandro Scordo (L.N.F.) (in behalf of AMADEUS experiment)23° Indian-Summer School of Physics & 6° HADES Summer School 2011
The AMADEUS experiment: a brief introductionTrigger system requirementsMPPC working principle and status of art10 channels prototype and MPPC characterizationResults of tests on DAFNE
New electronics and 64 channels prototypeTests on hadronic beamConclusions
Contents
DAΦNE
KLOE
The AMADEUS experiment: a brief introduction
- The main aim of AMADEUS is to confirm or deny the existance of Kaonic Clusters, - EXTENDED PROGRAM: Low-energy interactions, cross sections in light nuclei, decay of resonance states and exotic channels in nuclear medium will be studied
The AMADEUS experiment: a brief introductionDeeply Bound Kaonic Nuclear StatesFirst suggested by S.Wycech (1986)
Y.Akaishi and T. Yamazaki (Phys. Rev. C65 (2002) 044005)“Nuclear bound states in light nuclei”
Normal Nuclear binding energy parameters:
Ebind ~ 20 MeVG ~ 100 MeV
DBKNS binding energy parameters:
Ebind ~ 100 MeVG ~ 30 MeV
K- + 4He reaction(3-barionic state)
New kind of matter withastrophysical implications(Neutron stars, prof. Heuser talk)
Target: A gaseous He target for a first phase of study
First 4p fully dedicated setup!
The AMADEUS experiment: a brief introduction
Trigger system requirements
Multi Pixel Photon Counters (MPPC)
1) Small dimensions2) Working in magnetic field3) Working at room temperature4) Very good time resolution (s ~ 300 ps)5) High efficiency
MPPC : working principleP-N junction array working in Geiger mode (micropixel)
Output signal is the sum of all the micropixels
Each micropixel gives a high gain signal (105 – 106) indipendent of the number of incident photonsand has a fixed amplitude (binary mode)
First prototype and MPPC characterization
Is cooling needed ?
A scintillating fiber is activated by a beta Sr90 source
Both ends are coupled to detectors; one is used as trigger
First prototype and MPPC characterization
Studying rates with and without the beta source, it turned out that starting from the 4th p.e. peak, dark count contribute is negligible
This means that non cooling is needed in this case!!!!
Montecarlo simulations: what are we expecting?Momentum distribution of kaons is taken from Kloe Monte Carlo
BCF-10 1mm
diameter
Kaons are expected to leave almost a factor 7
more energy
than MIP electrons
GEANT3 simulation
MIPs coming from the I.P. are below the KM threshold
• KM scintillator at 6 cm from Interaction Point• Fibers 5 cm below the lowest scintillator• RF/2 and KM coincidence as DAQ trigger• Pure KM signal also collected
Results of tests on DAФNE
Kaon Monitor TDC (upper/lower coincidence)
Single peak resolution Is ~ 100 ps
MIP/K separation ~ 1 ns
MPPC tdc spectra
Single peak resolution Is ~ 300 ps
Missing MIPs
Results of tests on DAФNE
K-
MIPs
New electronics and 64 channels prototype32 Sci-Fi read at both sides
2 indipendent double layers with adjustable angle
Amplification of a factor 10
64 Constant Fraction Discr.
Logic OR of all detectors
Single particle conditon
(to be further checked)
Scintillator 1 Scintillator3&2
1
2 4
3
Tests on hadronic beam pM-1 beam at Paul Scherrer Institute (PSI, Zurich)
p,m,e-,p beam(similar to DAFNE situation)
Double anular setup
DAQ trigger:Sc1&Sc2
Single layer efficiencyDouble layer efficiency
Tests on hadronic beam: efficiency
Fiber 5: eff = 99 %
Fiber 6 : eff = 98,4 %
73% 92%
70% 90%
2,4% 5,2%
6,5% 2%
4,6% 2%
1% 0,06%
Fired fibers of layer 4 if fiber i of layer 4 is fired
Tests on hadronic beam: cross talk
Conclusions…
Temperature feedback circuit implementationNew efficiency measurements with scintillatorsNew tests in DAFNENew ideas and applications for this nice setup
…and future plans
1) Small dimensions 2) Working in magnetic field3) Working at room temperature4) Very good time resolution (s ~ 300 ps)5) High efficiency …
Luminescence of carriers can also be absorbed by another pixel giving a noise signal
Thermally generated electrons can activate the avalanche process in some pixel, with a high rate of 105-106 Hz (dark current)
The main contribute is a peak corresponding to 1 pixel (photoeletron)
MPPC : working principle
First prototype and MPPC characterization
Pre-Amplifiers (X 100)
SiPM (HAMAMATSU U50) (400 pixels)Operating voltage ~70V
Scintillating fibersBicron BCF-10 (blue)
5 Channles HVpower supply(stability better than10 mV)
Sr90 beta source (37 MBq)
First prototype and MPPC characterization
Black spectra are the trigger-used MPPC
Red spectra are the signal outputs of the NON trigger MPPC
Peak with mostcounts: 5 p.e. (15%)
Threshold at 5 p.e.
Fiber
Laser
HV HV
MPPC
RF
Preamp
Coincidence
TDC
RF/n RF=90 MHz (≈ RF/4)n ≈ 10000
New electronics and 64 channels prototype
s ~ 200 ps
No jitter from photon generation(to be considered)
Tests on hadronic beam: “relative” efficiency
Fiber 5: eff = 27,3 %
Fiber 6: eff = 30,1 %
In the case of non parallel double layers the geometrical efficiency is drastically reduced
Tests on hadronic beam: “relative” efficiency
Fiber 5: eff = 27,3 %
Fiber 6: eff = 30,1 %
In the case of non parallel double layers the geometrical efficiency is drastically reduced