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..

1. Verification of a Novel Calorimeter
Concept for
Studies of Charmonium States
●
Motivation of charm physics
●
Experiment with antiprotons: PANDA
Elmaddin Guliyev ●
PANDA Electromagnetic Calorimeter
Thesis defense date October 31 ●
Signal analysis for PANDA EMC
●
Performance studies
Promotor: Prof. dr. H. Löhner Time and energy resolution
Sampling ADC optimization
Copromotor: Dr. M. Kavatsyuk ●
On-line signal processing
●
Physics evaluation of PANDA EMC
●
Summary

2. 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

3. Strong coupling
Asymptotic freedom:
Quantum Chromodynamics
(QCD) is well tested at high
energies:
strong coupling constant αs
is small.
Confinement:
Large distance →
formation of hadrons:
strong coupling constant αs
increases drastically.
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 3

4. 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

5. Charmonium
Mesons containing a charm quark and
anti-charm quark.
Spectrum of charmonium states:
testing ground for the nature of the
strong interaction.
What we can learn
about strong interaction?
Example
Orbital momentum
and spin dependence
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 5

6. antiProton ANnihilations at Darmstadt
Charmonium
How we can produce such systems:
1. e-e+ collisions
2. two photon collisions
3. p ̄ interactions
p
All possible charmonium states
can be directly populated
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 6

7. antiProton ANnihilations at Darmstadt
Exotic states
Physics program:
Hybrid states
Tetraquark meson
Molecular states: X(3872) ?
Small cross sections require high luminosity!
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 7

8. antiProton ANnihilations at Darmstadt
High Energy Storage Ring (HESR) for antiprotons
electron cooling
stochastic
cooling
50 m
High luminosity 2·1032cm-2 s-1 PANDA
High momentum resolution σp / p = 10-5 target
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept
8

9. antiProton ANnihilations at Darmstadt
Charmonium
Mesons containing a charm quark and
anti-charm quark.
Spectrum of charmonium states:
testing ground for the nature of the
strong interaction.
Example:
hc(1P1) → ηc + γ → η + 0 + 0 + γ → 7 γ
ηc(1S0)→ γ + γ → 2 γ
J/ψ→ e+ + e-
Required: Electromagnetic Calorimeter!
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 9

10. antiProton ANnihilations at DArmstadt
PANDA Detector
cover 4π solid angle,
high luminosity → operation with high rates (2·107 annihilations/s)
physics program requires:
have a good
- particle identification
- momentum resolution for γ, e, μ, π, K and p
- vertex reconstruction
excellent calorimetry
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 10

11. antiProton ANnihilations at DArmstadt
Electromagnetic Calorimeter (EMC)
detection of photons, electrons, and positrons
4π 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
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 11

12. antiProton ANnihilations at DArmstadt
EMC detector material and photo sensor
PWO (PbWO4) scintillator Large Area Avalanche Photodiode (LAAPD)
Density 8.29 g/cm3 Size 7 X 14 mm2
Light yield (-250C) 500 ph/MeV 2 LAAPD per crystal
(NaI(Tl): 38000 ph/MeV) Photograph of
Decay time ~ 6 – 30 ns two standard (5 X 5 mm2) APDs
Size ~ 20 X 20 X 200 mm3 one square LAAPD (10 X 10 cm2)
17000 PWO crystals one rectangular (7 X 14 mm2) LAAPD
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 12

13. antiProton Annihilations at DArmstadt
The preamplifier
Low Noise low Power (LNP),
Basel Univ. design
one-channel, Preamplifier pulse
single-range,
discrete-component, 25 µs decay time
size 18 X 47 mm2,
no-shaping.
APFEL ASIC,
GSI design,
two-channel, ASIC pulse
dual-range,
250 ns shaping.
Developed by
T.Poelman
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 13

14. antiProton ANnihilations at Darmstadt
Signal 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 14

15. Signal analysis for PANDA EMC
Implementation of trigger-less DAQ
To realize the trigger-less DAQ, sampling of preamplifier signal
each sub-detector must
independently:
detect hits,
report to DAQ.
Realized by
Sampling ADC (SADC):
Analog output of preamplifier
is periodically measured.
Obtained data must be 10 ns
processed on-line.
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 15

16. Signal analysis for PANDA EMC
Layout 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.
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 16

17. Signal analysis for PANDA EMC
Sampling ADC
- verify the performance for physics analysis
- develop data-processing algorithm
- find optimal parameters for digitizer
commercial STRUCK SIS3302 Module
8 channel
100 MHz sampling rate
16-bit resolution
5 FPGA
For on-line pulse processing
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 17

18. Performance studies
Experimental setups
Carbon fiber
single crystal setup: array of 60 crystals containers
EMC Prototype setup
4 crystals packed in
reflective material
Studied: Performance of Time and Energy resolution
Optimization of Sampling procedure
Implementations in FPGA
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 18

19. Signal analysis for PANDA EMC
Energy
Digital Filter
Input (SADC data) (shape+noise reduction) Pulse detection
Timing method Time
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 19

20. Signal analysis for PANDA EMC
Data-processing algorithm
digital Constant Fraction Timing
raw time-stamp
filtered
energy
rms = 0.4 ns
difference of time-stamps
amplitude
distribution M.Kavatsyuk,E.Guliyev et al., NIM A 648, 77 (2011)
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 20

21. Performance studies
Timing performance
from time coincidences with LED light pulser
∆tRMS = rmscoincidence time / √2.
Single crystal setup
Cosmic muon energy
equivalent (20 MeV)
Influence of noise level
We can reach resolution well below 1 ns
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 21

22. Performance studies
Timing performance
Timing performance with LED light pulser, CFT linearity
Single crystal setup
Linearity between analog (TDC) and digital CFT method
Digital CFT method works properly
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 22

23. Performance studies
Timing performance with EMC Prototype
3X3 crystal array setup
High energy
photon beam:
beam directed
between two crystals
For energy deposition higher than 80 MeV: time resolution less than 1 ns
Sufficient to complete PANDA mission!
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 23

24. Performance studies
Energy resolution study with EMC Prototype
Epeak = 0.671 GeV
σ = 0.024 GeV
3X3 crystal array
λ = 0.032 GeV
Photon response for 3X3 crystal Incident photon energy:
array for different incident E = 0.685 GeV
photon energies.
Asymmetric response curve → σ for energy resolution
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 24

25. Performance studies
Energy resolution study with EMC Prototype
σ/E = a + b/√E(GeV)
a (50 MHz) = 0.35 %
3X3 crystal array
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

26. FPGA Implementation
(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
Single crystal setup
Implementation tested with
LED light pulser on XILINX development board
LED light pulser and cosmic muons on STRUCK SADC
E.Guliyev, M.Kavatsyuk et al., NIM A (2011) accepted
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 26

27. FPGA Implementation
(Field Programmable Gate Array)
Test with XILINX development board and SADC
SADC data SADC data
from crystal setup
Single crystal setup
Time
Energy
Debug
binary switch
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 27

28. FPGA Implementation
Block diagram of signal processing in FPGA
Event
Single crystal setup
selection
Filter 1: Filter 3:
shaping noise reduction
Filter 2:
shaping
Fast, compact, efficient block structure
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 28

29. FPGA Implementation
Block diagram of signal processing in FPGA
Event
Single crystal setup
selection
Filter 1: Filter 3:
shaping noise reduction
Filter 2:
shaping
In ASIC preamplifier case Filter 1 and Filter 2 are bypassed
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 29

30. FPGA Implementation
Debug mode
Raw trace Filtered traces
Single crystal setup
CFT trace
To follow any intermediate step
→ check proper operation,
fast processing, typ. 80 ns
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 30

31. FPGA Implementation
(Field Programmable Gate Array)
LED light pulser test for XILINX development board
Energy resolution Time resolution
Single crystal setup
The correlation coefficient is 99.9% between off-line and FPGA processing
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 31

32. FPGA Implementation
(Field Programmable Gate Array)
LED light pulser test for SADC
Energy resolution Time resolution
Single crystal setup
The correlation coefficient 99.9% between off-line and
on-line pulse processing
The implementation is working as expected !
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 32

33. Physics Evaluation
Validation of simulation: Experiment vs. Simulation
Single photon fire the 3X3 crystal array
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

34. Physics Evaluation
hc(1P1) → ηc + γ → η + 0 + 0 + γ → 7 γ
Has high branching ratio
54.3 ± 6.7 ± 5.2%
PANDA EMC response ability
Final state 7 γ, only EMC response σ
Simulated different noise in electronics
and different detector thresholds
High electronic noise ==> worse resolution !
Width (MeV)
digital pulse filtering superior
to analog readout
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 34

35. Physics Evaluation
Threshold dependence
achieved with digital filtering
PANDA EMC response ability
Lower noise level → lower thresholds
Lower cluster threshold → higher photon statistics, smaller width,
higher efficiency
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept 35

36. 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

37. 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

38. BackUp Slides
Time resolution for different case – huge discrepancy LED and particle measurement
Timing study
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept for Studies of Charmonium States B1

39. BackUp Slides
Preamplifier output is different for same condition, temperature, energy dep. etc
Timing study
WHY?
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept for Studies of Charmonium States B2

40. Timing study BackUp Slides
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)
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept for Studies of Charmonium States B2

41. Timing study BackUp Slides
Sum of number of photons as a function of arrival time of photons
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept for Studies of Charmonium States B3

42. Timing study BackUp Slides
Experimental study of decay time
(or pulse rise time)
Influence to time resolution
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept for Studies of Charmonium States B4

43. Specifications
To optimize the SADC parameter
Single crystal setup 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

44. Single crystal setup
FPGA Implementation
Comparison of pulse amplitudes obtained as MWD amplitude m[soft] and m[fpga] for the software
analysis and the FPGA processing, respectively. According to the cosmic-ray calibration, the lower
amplitude corresponds to 80 MeV and the higher one to 390 MeV. The correlation coefficient is
99.9%.
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept B6

45. FPGA Implementation
On-line cosmic muon measurement:
raw spectrum and coincidence spectrum.
Single crystal setup
Time stamp difference distribution for off-line
and on-line pulse processing.
Off-line On-line
18.10.11 E.Guliyev, Verification of a Novel Calorimeter Concept B7