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Particle physics has revealed the fundamental and elementary constituents of matter, quarks and leptons. However, it remains a challenge to understand how composite particles like nucleons, the building blocks of atomic nuclei, can gain their mass from massless constituents. Insight is best obtained by studying composite systems containing a heavy “charm” quark, or by demonstrating a predicted new “exotic” type of composite systems with yet unobserved quark combinations. Such systems can be produced through intense antimatter annihilations at the new accelerator complex FAIR (Germany) in the near future. The systems of interest have to be studied with high-precision particle beams but also with detectors of ultimate accuracy. Photons of high energy, which are among the most abundant decay products of the short-lived charm- or exotic particles, will be measured in a large crystal spectrometer. Essential electronic components of such a detector and the corresponding analysis techniques have been developed and studied in this thesis. A new approach to precisely evaluate the large amount of measured signals in programmed chip-arrays and to exactly determine their characteristic features has been verified in various experiments using accelerated particles and cosmic rays. The results presented in this thesis demonstrate that a large data rate can be reliably and precisely processed, which is mandatory to investigate a huge amount of annihilation events. The logic components and program elements have been fitted to commercially available devices. Interest in our developments has been shown from a commercial company and foreign experimental groups..
Citation preview
Verification of a Novel Calorimeter Concept for
Studies of Charmonium States
Elmaddin Guliyev
Thesis defense date October 31
Promotor: Prof. dr. H. Löhner Copromotor: Dr. M. Kavatsyuk
● Motivation of charm physics● Experiment with antiprotons: PANDA ● PANDA Electromagnetic Calorimeter
● Signal analysis for PANDA EMC
● Performance studiesTime and energy resolution
Sampling ADC optimization
● On-line signal processing
● Physics evaluation of PANDA EMC
● Summary
The origin of hadron mass
More than 99% of the visible Universe is made of protons and neutrons (u, d quarks)
Proton/neutron are much heavier than their quark and gluon constituents!
Expect an answer from systems with heavy quarks: Charm
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 2
Strong coupling
3 18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept
Asymptotic freedom:
Quantum Chromodynamics (QCD) is well tested at highenergies: strong coupling constant α
s
is small.
Confinement:
Large distance →formation of hadrons:strong coupling constant α
s
increases drastically.
Charmonium
Mesons containing a charm quark and anti-charm quark.
Spectrum of charmonium states:testing ground for the nature of the strong interaction.
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 4
Charmonium
Orbital momentum
and spin dependence
What we can learn
about strong interaction?
Exa
mpl
e
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 5
Mesons containing a charm quark and anti-charm quark.
Spectrum of charmonium states:testing ground for the nature of the strong interaction.
antiProton ANnihilations at DarmstadtCharmonium
How we can produce such systems:
1. e-e+ collisions
2. two photon collisions
3. interactions p p̄
All possible charmonium states can be directly populated
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 6
antiProton ANnihilations at DarmstadtExotic states
Physics program:
Tetraquark meson
Hybrid states
Molecular states: X(3872) ?
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 7
Small cross sections require high luminosity!
antiProton ANnihilations at DarmstadtHigh Energy Storage Ring (HESR) for antiprotons
8 18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept
PANDAtarget
electron cooling
stochastic cooling
High luminosity 2·1032cm-2 s-1
High momentum resolution σp
/ p = 10-5
50 m
antiProton ANnihilations at DarmstadtCharmonium
9 18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept
Mesons containing a charm quark and anti-charm quark.
Spectrum of charmonium states:testing ground for the nature of the strong interaction.
Example:h
c(1P
1) → η
c + γ → η + 0 + 0 + γ → 7 γ
ηc(1S
0)→ γ + γ → 2 γ
J/ψ→ e+ + e-
Required: Electromagnetic Calorimeter!
antiProton ANnihilations at DArmstadt PANDA Detector
10 18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept
physics program requires: have a good - particle identification - momentum resolution for γ, e, μ, π, K and p - vertex reconstructionexcellent calorimetry
cover 4π solid angle,high luminosity → operation with high rates (2·107 annihilations/s)
antiProton ANnihilations at DArmstadt
11 18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept
Electromagnetic Calorimeter (EMC)
detection of photons, electrons, and positrons4π coverage
three parts - Barrel, Forward and Backward Endcaps
wide dynamic range: 10 MeV up to 10 GeV
low threshold ~ 1 MeV
Have a high
Energy Resolution
Time Resolution
Position Resolution
antiProton ANnihilations at DArmstadt
12 18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept
EMC detector material and photo sensor
PWO (PbWO4) scintillatorDensity 8.29 g/cm3 Light yield (-250C) 500 ph/MeV(NaI(Tl): 38000 ph/MeV)Decay time ~ 6 – 30 nsSize ~ 20 X 20 X 200 mm3
17000 PWO crystals
Large Area Avalanche Photodiode (LAAPD)Size 7 X 14 mm2 2 LAAPD per crystalPhotograph of two standard (5 X 5 mm2) APDs one square LAAPD (10 X 10 cm2) one rectangular (7 X 14 mm2) LAAPD
13 18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept
The preamplifier
antiProton Annihilations at DArmstadt
Low Noise low Power (LNP), Basel Univ. design one-channel, single-range, discrete-component,size 18 X 47 mm2,
no-shaping.
Preamplifier pulse
25 µs decay time
APFEL ASIC, GSI design, two-channel,dual-range, 250 ns shaping.
Developed by T.Poelman
ASIC pulse
14 18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept
antiProton ANnihilations at DarmstadtSignal analysis for PANDA EMC
High annihilation rate – 20 MHz
event rate 500 kHz for single detector
efficient event selection based on physics(e.g. secondary vertex, momentum of reconstructed particles.)
New approach for data acquisition (DAQ): “trigger-less”
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 15
Signal analysis for PANDA EMCImplementation of trigger-less DAQ
To realize the trigger-less DAQ, each sub-detector mustindependently: detect hits, report to DAQ.
Realized bySampling ADC (SADC):
Analog output of preamplifieris periodically measured.
Obtained data must be processed on-line.
10 ns
sampling of preamplifier signal
16 18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept
Signal analysis for PANDA EMCLayout of readout electronics chain for PANDA EMC
To build the trigger-less readout: preamplifier signals digitized by SADC,
processed on-line by Field Programmable Gate Array (FPGA):
Many logic cells with programmable connections→ Developed the program logic,
Prepared algorithm for implementation on commercial SADC.
17 18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept
Signal analysis for PANDA EMC Sampling ADC
commercial STRUCK SIS3302 Module
8 channel
100 MHz sampling rate
16-bit resolution
5 FPGA
- verify the performance for physics analysis
- develop data-processing algorithm
- find optimal parameters for digitizer
For on-line pulse processing
Performance studiesExperimental setups
single crystal setup:EMC Prototype setup
Studied: Performance of Time and Energy resolution
Optimization of Sampling procedure
Implementations in FPGA
18 18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept
array of 60 crystalsCarbon fibercontainers
4 crystals packed in reflective material
19 18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept
Signal analysis for PANDA EMC
Input (SADC data)Digital Filter
(shape+noise reduction) Pulse detection
Timing method Time
Energy
Signal analysis for PANDA EMCData-processing algorithm
time-stamp
ener
gy
difference of time-stamps
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 20
amplitude distribution
raw
filtered
digital Constant Fraction Timing
rms = 0.4 ns
M.Kavatsyuk,E.Guliyev et al., NIM A 648, 77 (2011)
21
Performance studiesTiming performance
from time coincidences with LED light pulser
Influence of noise level
Sing
le c
ryst
al se
tup
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept
∆tRMS = rmscoincidence time
/ √2.
Cosmic muon energy
equivalent (20 MeV)
We can reach resolution well below 1 ns
Performance studiesTiming performance
Timing performance with LED light pulser, CFT linearity
Sing
le c
ryst
al se
tup
Linearity between analog (TDC) and digital CFT method
Digital CFT method works properly
22 18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept
Performance studies Timing performance with EMC Prototype
3X3
crys
tal a
rray
setu
p
For energy deposition higher than 80 MeV: time resolution less than 1 ns
Sufficient to complete PANDA mission!
23 18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept
High energy photon beam:
beam directed between two crystals
Performance studiesEnergy resolution study with EMC Prototype
3X3
crys
tal a
rray
Incident photon energy:E = 0.685 GeV
Epeak
= 0.671 GeV
λ = 0.032 GeV
σ =
0.02
4 G
eV
Photon response for 3X3 crystalarray for different incidentphoton energies.
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 24
Asymmetric response curve → σ for energy resolution
Performance studiesEnergy resolution study with EMC Prototype
3X3
crys
tal a
rray
σ/E = a + b/√E(GeV)
a (50 MHz) = 0.35 % b (50 MHz) = 1.97 %
a (100 MHz) = 0.42 % b (100 MHz) = 2.04 %
a (analog) = 0.31 % b (analog) = 2.44 %
The energy resolution can compete with analog readout;
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 25
FPGA ImplementationSi
ngle
cry
stal
setu
p
(Field Programmable Gate Array)
On-line extraction of energy and time information,
Applicable for different pulse shapes,
Data processing algorithm implemented in VHDL code
by KVI electronics engineer P.J.J. Lemmens
Implementation tested with
LED light pulser on XILINX development board
LED light pulser and cosmic muons on STRUCK SADC
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 26
E.Guliyev, M.Kavatsyuk et al., NIM A (2011) accepted
FPGA ImplementationSi
ngle
cry
stal
setu
p
(Field Programmable Gate Array)
Test with XILINX development board and SADC
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 27
SADC data
TimeEnergyDebug
SADC datafrom crystal setup
binary switch
FPGA ImplementationBlock diagram of signal processing in FPGA
Sing
le c
ryst
al se
tup
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 28
Fast, compact, efficient block structure
Filter 1:shaping
Filter 2:shaping
Filter 3:noise reduction
Event selection
FPGA ImplementationBlock diagram of signal processing in FPGA
Sing
le c
ryst
al se
tup
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 29
In ASIC preamplifier case Filter 1 and Filter 2 are bypassed
Filter 1:shaping
Filter 2:shaping
Filter 3:noise reduction
Event selection
FPGA Implementation Debug mode
To follow any intermediate step→ check proper operation,
fast processing, typ. 80 ns
Sing
le c
ryst
al se
tup
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 30
Raw trace Filtered traces
CFT trace
FPGA ImplementationSi
ngle
cry
stal
setu
p
(Field Programmable Gate Array)
The correlation coefficient is 99.9% between off-line and FPGA processing
LED light pulser test for XILINX development board
Energy resolution Time resolution
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 31
FPGA ImplementationSi
ngle
cry
stal
setu
p
(Field Programmable Gate Array)
LED light pulser test for SADC
The correlation coefficient 99.9% between off-line and
on-line pulse processing
The implementation is working as expected !
Energy resolution Time resolution
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 32
Physics Evaluation Validation of simulation: Experiment vs. Simulation
Sing
le p
hoto
n fir
e th
e 3X
3 cr
ysta
l arr
ay
200 MeV single photons
0.3 MeV noise level
1 MeV single
crystal threshold
Good agreement!
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 33
Physics EvaluationPA
ND
A E
MC
res
pons
e ab
ility
hc(1P
1) → η
c + γ → η + 0 + 0 + γ → 7 γ
Has high branching ratio
54.3 ± 6.7 ± 5.2%
Final state 7 γ, only EMC response
Simulated different noise in electronics
and different detector thresholds
High electronic noise ==> worse resolution !
digital pulse filtering superior
to analog readout
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 34
σ
Wid
th (M
eV)
Physics EvaluationThreshold dependence
Lower noise level → lower thresholds
Lower cluster threshold → higher photon statistics, smaller width, higher efficiency
PAN
DA
EM
C r
espo
nse
abili
ty
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 35
achieved with digital filtering
WHAT HAVE WE ACHIEVED?
First essential step in constructing a trigger-less DAQ:● Developed on-line feature-extraction algorithm.● Achieved time and energy resolution sufficient to complete
the physics program: ● Low noise level: 0.3 MeV.● Energy resolution: 2.4% at 1 GeV.● Time resolution: 1 ns at 0.08 GeV energy deposition.
● Optimized SADC parameters for best performance: Sampling speed, bit resolution, power consumption.
● Demonstrated importance of optimization for physics performance.
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 36
SUMMARY
1. Digital readout electronics developed. 2. Novel calorimeter concept verified
using photon beams. 3. Promising results achieved: energy, time resolution;
fast on-line processing.
4. First step towards trigger-less DAQ chain.
Thanks to Peter Lemmens for electronics support!
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept
B1
BackUp Slides
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept for Studies of Charmonium States
Tim
ing
stud
y
Time resolution for different case – huge discrepancy LED and particle measurement
B2
BackUp Slides
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept for Studies of Charmonium States
Tim
ing
stud
y
Preamplifier output is different for same condition, temperature, energy dep. etc
WHY?
B2
BackUp Slides
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept for Studies of Charmonium States
Tim
ing
stud
y
GEANT 4 simulation for 100 MeV photon
Hits the end face of PWO crystal
Distribution of arrival time of optical photons
for different decay time:
15 ns (top panel)
30 ns (bottom panel)
B3
BackUp Slides
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept for Studies of Charmonium States
Tim
ing
stud
y
Sum of number of photons as a function of arrival time of photons
B4
BackUp Slides
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept for Studies of Charmonium States
Tim
ing
stud
y
Experimental study of decay time
(or pulse rise time)
Influence to time resolution
Specifications To optimize the SADC parameter
Sing
le c
ryst
al se
tup
with
ion
beam
50 MHz sampling rate is sufficient to obtain energy and time resolution.
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept B5
FPGA ImplementationSi
ngle
cry
stal
setu
p
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept B6
Comparison of pulse amplitudes obtained as MWD amplitude m[soft] and m[fpga] for the softwareanalysis and the FPGA processing, respectively. According to the cosmic-ray calibration, the loweramplitude corresponds to 80 MeV and the higher one to 390 MeV. The correlation coefficient is99.9%.
Off-line On-line
FPGA ImplementationSi
ngle
cry
stal
setu
p
On-line cosmic muon measurement:
raw spectrum and coincidence spectrum.
Time stamp difference distribution for off-line
and on-line pulse processing.
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept B7