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- Appagere, Gandharva
(författare)
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Λ-Λ hyperons: the road to estimate the production cross-section in protonproton collisions
- 2024
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this study, we analyse the $\Lambda$-$\Lambda$ hyperon channel in proton-proton scattering, $pp \mapsto \Lambda\Lambda + K^+K^+, \,\,\Lambda\mapsto p+\pi^-$, with a proton beam energy of $4.5$ GeV using the High Acceptance Di-Electron Spectrometer (HADES) at GSI.The purpose of the study presented here is to measure the production cross-section for the $\Lambda$-$\Lambda$ channel. %at the above beam Kinetic energy. The following measurement will be the first at this energy scale (CoM: $\sqrt{s}=3.46$ GeV).We develop a multi-stage analysis strategy to first determine the acceptance-reconstruction efficiency for the $\Lambda$-$\Lambda$ channel from simulations produced according to phase space.The analysis of data is perforned for three different event selections: inclusive ($ pp \mapsto \Lambda\Lambda + X$), semi-exclusive ($ pp \mapsto \Lambda\Lambda + K^+ +X$) and the fully exclusive.For each selection, the data is represented by a two-dimensional histogram, where the axes correspond to the $p+\pi^-$ invariant mass of the respective $\Lambda$ candidate. %The same strategy was employed on the experimental data to build a $\Lambda$-$\Lambda$ 2D correlation matrix. The \sloppy{$\Lambda$-$\Lambda$ signal} is determined using a Statistical sideband analysis (SSB) and a Linear least squares (LLS) fit.The inclusive selection provides the most significant $\Lambda$-$\Lambda$ signal.Cross-section values corresponding to the two analyses are calculated as weighted average of the result of the three selections.The production cross-section for $\Lambda$-$\Lambda$ in $pp$ collisions at $\sqrt{s}=3.46$ GeV is measured \sloppy{to be $59\pm27$ nb} (one standard deviation uncertainity).
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- Preston, Markus
(författare)
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Single event upsets: measurements and modelling of proton- and neutron-induced errors in a 28 nm SRAM-based FPGA
- 2018
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Single event upsets are radiation-induced errors affecting electronic devices, which can cause corruption of processed data. The electromagnetic calorimeter of the PANDA experiment — a hadron-physics experiment currently under development — will employ Xilinx Kintex-7 field-programmable gate arrays (FPGAs) in its readout electronics. During operation of the experiment, the FPGAs will be exposed to a high flux of radiation. Single-event upsets caused by protons and neutrons in the configuration memory of the FPGA have been studied through experiments and theoretical modelling. The device was irradiated with protons and neutrons of energies up to 184 MeV, and the corresponding single event upset cross sections were determined. In order to describe the energy-dependence of the cross sections, and to predict the error rates during operation of PANDA, a Monte Carlo model of energy-deposition mechanisms in silicon has been developed. The model predictions agree well with the experimental data for both protons and neutrons. Using the developed model, the mean time between failures due to neutrons during initial operation of PANDA is estimated to be 180 ± 40 hours per FPGA.
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