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Common Mode Effect of the ALICE Transition Radiation Detector - Baseline Shift

The Transition Radiation Detector is a sub-detector of the ALICE experiment that is used primarily as an electron detector and a trigger mechanism. The TRD currently has 521 individual chambers distributed over 18 super modules. Each chamber houses a radiator, a drift region and a multi-wire proport...

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Main Author: Elimam, Ali
Other Authors: Dietel, Thomas
Format: Thesis
Language:English
Published: Department of Electrical Engineering 2021
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access_status_str Open Access
author Elimam, Ali
author2 Dietel, Thomas
author_browse Dietel, Thomas
Elimam, Ali
author_facet Dietel, Thomas
Elimam, Ali
author_sort Elimam, Ali
collection Thesis
description The Transition Radiation Detector is a sub-detector of the ALICE experiment that is used primarily as an electron detector and a trigger mechanism. The TRD currently has 521 individual chambers distributed over 18 super modules. Each chamber houses a radiator, a drift region and a multi-wire proportional chamber with the readout electronics. When charge is absorbed in the anode wires of the multi-wire proportional chamber, it creates a common-mode effect, this common-mode effect manifests itself as a drop in the signal produced by the surrounding readout electronics where no particle has traversed, called the baseline. Capacitors have been installed in a layout to produce a low-pass filter (RC circuit) to decrease the impact of the common-mode effect. These capacitors were installed for a pad row pair, creating capacitor coupling for a high voltage supply segment. However, these capacitors were prone to failure, causing dead chambers that could not be used to acquire data for the remainder of the run, so it was decided to remove them. With their removal, the extent of the common-mode effect on the baseline had to be understood and corrected for in order to better calibrate the detector system. The University of Cape Town has one chamber, an L3C0 chamber. This chamber was used to collect two datasets with the same parameters, one with the 2.2 nF capacitors installed and the other without the 2.2 nF capacitors, to study the effect. It is found that the drop in baseline is only experienced by anode wires with the same capacitor coupling. Furthermore, it is observed that there is a linear relationship between the charge absorbed by the anode wires and the drop in baseline, thus charge absorbed by the anode wires can be summed should they have the same capacitor coupling. It is also found that the drop in baseline is 2.5 times larger in the dataset without capacitors. The final part of the thesis corrects for this common-mode effect, using a correction factor determined from the dataset
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id oai:open.uct.ac.za:11427/33718
institution University of Cape Town (South Africa)
language eng
last_indexed 2026-06-10T12:32:58.612Z
license_str Not specified — see source repository
provenance_str_mv Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository
publishDate 2021
publishDateRange 2021
publishDateSort 2021
publisher Department of Electrical Engineering
publisherStr Department of Electrical Engineering
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source_str UCTD — University of Cape Town Open Access Repository
spelling oai:open.uct.ac.za:11427/33718 Common Mode Effect of the ALICE Transition Radiation Detector - Baseline Shift Elimam, Ali Dietel, Thomas Nuclear Power The Transition Radiation Detector is a sub-detector of the ALICE experiment that is used primarily as an electron detector and a trigger mechanism. The TRD currently has 521 individual chambers distributed over 18 super modules. Each chamber houses a radiator, a drift region and a multi-wire proportional chamber with the readout electronics. When charge is absorbed in the anode wires of the multi-wire proportional chamber, it creates a common-mode effect, this common-mode effect manifests itself as a drop in the signal produced by the surrounding readout electronics where no particle has traversed, called the baseline. Capacitors have been installed in a layout to produce a low-pass filter (RC circuit) to decrease the impact of the common-mode effect. These capacitors were installed for a pad row pair, creating capacitor coupling for a high voltage supply segment. However, these capacitors were prone to failure, causing dead chambers that could not be used to acquire data for the remainder of the run, so it was decided to remove them. With their removal, the extent of the common-mode effect on the baseline had to be understood and corrected for in order to better calibrate the detector system. The University of Cape Town has one chamber, an L3C0 chamber. This chamber was used to collect two datasets with the same parameters, one with the 2.2 nF capacitors installed and the other without the 2.2 nF capacitors, to study the effect. It is found that the drop in baseline is only experienced by anode wires with the same capacitor coupling. Furthermore, it is observed that there is a linear relationship between the charge absorbed by the anode wires and the drop in baseline, thus charge absorbed by the anode wires can be summed should they have the same capacitor coupling. It is also found that the drop in baseline is 2.5 times larger in the dataset without capacitors. The final part of the thesis corrects for this common-mode effect, using a correction factor determined from the dataset 2021-08-06T08:58:49Z 2021-08-06T08:58:49Z 2021 2021-08-06T08:01:28Z Master Thesis Masters MSc (Eng) http://hdl.handle.net/11427/33718 eng application/pdf Department of Electrical Engineering Faculty of Engineering and the Built Environment
spellingShingle Nuclear Power
Elimam, Ali
Common Mode Effect of the ALICE Transition Radiation Detector - Baseline Shift
thesis_degree_str Master's
title Common Mode Effect of the ALICE Transition Radiation Detector - Baseline Shift
title_full Common Mode Effect of the ALICE Transition Radiation Detector - Baseline Shift
title_fullStr Common Mode Effect of the ALICE Transition Radiation Detector - Baseline Shift
title_full_unstemmed Common Mode Effect of the ALICE Transition Radiation Detector - Baseline Shift
title_short Common Mode Effect of the ALICE Transition Radiation Detector - Baseline Shift
title_sort common mode effect of the alice transition radiation detector baseline shift
topic Nuclear Power
url http://hdl.handle.net/11427/33718
work_keys_str_mv AT elimamali commonmodeeffectofthealicetransitionradiationdetectorbaselineshift