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@PHDTHESIS{Noll:237436,
author = {Noll, Ernst Johannes Oliver},
othercontributors = {Maas, Frank},
title = {{D}igital {S}ignal {P}rocessing for the {M}easurement of
{P}article {P}roperties with the {PANDA} {E}lectromagnetic
{C}alorimeter},
school = {Johannes-Gutenberg Universität Mainz},
type = {Dissertation},
publisher = {Johannes Gutenberg-Universität Mainz},
reportid = {GSI-2021-00425},
pages = {198 Seiten},
year = {2020},
note = {Dissertation, Johannes-Gutenberg Universität Mainz, 2020},
abstract = {In recent decades, the quantum field theory of strong
interaction (QCD) has been impressively demonstrated in the
area of high energies and momentum transfers. Nowadays,
novel experiments allow for challenging the methods for the
calculation of QCD also in the non-perturbative regime by
the continuous improvement of measurement accuracy. PANDA at
the upcoming FAIR accelerator facility is one of such
experiments. At PANDA, antiprotons with momenta of up to 15
GeV/c will be annihilated at a fixed proton target under
high luminosities. Among a variety of detector systems,
PANDA stands out with its lead tungstate electromagnetic
calorimeter (EMC), which is designed to have a wide dynamic
range (10 MeV to 14.6 GeV) and a relative energy resolution
of better than 2.5 $\%$ at 1 GeV. The development of the
backward part of the PANDA EMC is the first scientific goal
of this thesis. Since the development of the backward EMC
has progressed so far, it is foreseen for an experiment
within the FAIR Phase-0 research programme. It is proposed
to measure the double-virtual electromagnetic transition
form factor (TFF) of the pion in the Primakoff π0
electroproduction at the Mainz Microtron facility (MAMI).
The pion TFF is related via the hadronic light-by-light
scattering to the $g_μ-2$ puzzle. Consequently, the second
scientific goal of this thesis are preparatory studies for
FAIR Phase-0. The developments of this work resulted in a
fully functional prototype calorimeter, which operated
stably in numerous tests at MAMI. However, the focus of this
work is digital signal processing (DSP) for the PANDA EMC. A
specially developed software framework allowed for testing
and optimising signal optimising algorithms and parameter
extraction methods on realistically simulated signals. Thus,
the algorithms are well-adapted to the time structure of the
PANDA calorimeter preamplifier (APFEL) signals. Furthermore,
the DSP methods were implemented on the Field Programmable
Gate Arrays (FPGAs) of the PANDA digitisation board. The
developed FPGA firmware provides a self-triggering readout
for all calorimeter channels, an efficient implementation of
a high order filter with a finite impulse response (FIR),
noise hit suppression and pileup handling. Together with the
calorimeter prototype, the digital signal processing was
tested at MAMI. Thanks to the use of the DSP methods, an
energy detection threshold (single crystal) of less than 2.5
MeV was achieved. This allowed for a measured relative
energy resolution of 2.190(2) $\%$ at 1 GeV. Moreover, the
non-linearity of the calorimeter is in the order of a few
per mill. Due to the self-triggering concept of the FPGA
firmware, measurements under high detector rates were
possible. Thus, a dead time of 464(13) ns and a pileup
probability of 4.53(12) $\%$ at 100 kHz was determined. For
the measurement of the pion TFF, a high flux of low energy
electrons and photons is expected. Thus, test beams with the
prototype were performed to determine the impact of the low
energetic background on the measurement. By utilising both
experimental data and simulations, an upper limit for the
relative energy resolution (2.75(4) $\%$ to 6.57(2) $\%$ at
1 GeV) as a function of the luminosity (2.77 μb-1/s to
55.34 μb-1/s) was found. The study allows an estimation of
the FAIR Phase-0 measuring time.},
cin = {MEP / PANDA@FAIR},
cid = {I:(DE-Ds200)MEP-20150313OR329 /
I:(DE-Ds200)Coll-FAIR-PANDA},
pnm = {612 - Cosmic Matter in the Laboratory (POF3-612)},
pid = {G:(DE-HGF)POF3-612},
experiment = {$EXP:(DE-Ds200)Experiment_without_proposal_number-20200803$},
typ = {PUB:(DE-HGF)11},
doi = {10.25358/OPENSCIENCE-5078},
url = {https://repository.gsi.de/record/237436},
}