Development and characterisation of novel silicon pixel detectors for tracking and timing
<p>To achieve a total integrated luminosity of 3,000 fb^(−1) collected after the High-Luminosity LHC upgrade, the ATLAS Inner Detector will be replaced by the Inner Tracker (ITk) with an increased demand for sensor radiation hardness. Based on the Low Gain Avalanche Detector (LGAD) technology,...
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| Format: | Thesis |
| Language: | English |
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2024
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| _version_ | 1824458861838336000 |
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| author | Gaži, M |
| author2 | Bortoletto, D |
| author_facet | Bortoletto, D Gaži, M |
| author_sort | Gaži, M |
| collection | OXFORD |
| description | <p>To achieve a total integrated luminosity of 3,000 fb^(−1) collected after the High-Luminosity LHC upgrade, the ATLAS Inner Detector will be replaced by the Inner Tracker (ITk) with an increased demand for sensor radiation hardness. Based on the Low Gain Avalanche Detector (LGAD) technology, the High-Granularity Timing Detector (HGTD) will be installed to mitigate against the effect of increased pile-up and enhance vertex separation with a 30 ps timing resolution per track.</p>
<p>This thesis presents the electrical characterisation of wafers from the first LGAD batch manufactured by Teledyne e2v, featuring samples with a range of gain layer
implant energy and dose. Multiple 1×1 mm^2 LGAD devices were tested in a test beam at the CERN North Area. The results demonstrate excellent hit efficiency (>99%), charge collection (>15 fC), and timing resolution below 20 ps.</p>
<p>Electrical measurements of the LGAD sensors after neutron irradiation give acceptor removal coefficients of 7-8×10^(16) cm^2, comparable to other non-carbon enriched LGAD productions. Post-irradiation laser injection tests demonstrated jitter better than 10 ps up to 5×10^(14) 1 MeV n_(eq)cm^(−2), with some devices maintaining charge gain of ∼15 and jitter <25 ps at fluences up to 2×10^(15) 1 MeV n_(eq)cm^(−2). This thesis also includes measurements of the inter-pad distance for multi-pad LGAD devices.</p>
<p>The MALTA2 sensor, developed as a monolithic candidate for the outermost layer of the ATLAS ITk, was extensively tested in a test beam with 180 GeV hadrons. The
investigation characterised samples up to neutron fluence of 5×10^(15) 1 MeV n_(eq)cm^(−2). Samples produced on the Czochralski (Cz) substrate demonstrated better radiation hardness than those on the epitaxial substrate, particularly with backside metallisation. At 3×10^(15) 1 MeV n_(eq)cm^(−2), MALTA2 Cz samples achieved superior performance with 98% efficiency and 6.3 ns RMS timing resolution.</p>
<p>Furthermore, this thesis outlines a preliminary investigation of improved clustering methods that use Time-of-Arrival information to enhance the spatial resolution of the
MALTA2 sample by ∼20% and improve the timing resolution by ∼7%. Further steps for generalisation of the method are also discussed.</p> |
| first_indexed | 2025-02-19T04:32:37Z |
| format | Thesis |
| id | oxford-uuid:14e6f4e7-dd13-4a7b-adb9-ea4656d5d07c |
| institution | University of Oxford |
| language | English |
| last_indexed | 2025-02-19T04:32:37Z |
| publishDate | 2024 |
| record_format | dspace |
| spelling | oxford-uuid:14e6f4e7-dd13-4a7b-adb9-ea4656d5d07c2025-01-20T09:54:37ZDevelopment and characterisation of novel silicon pixel detectors for tracking and timingThesishttp://purl.org/coar/resource_type/c_db06uuid:14e6f4e7-dd13-4a7b-adb9-ea4656d5d07cSilicon diodesEnglishHyrax Deposit2024Gaži, MBortoletto, DMcMahon, S<p>To achieve a total integrated luminosity of 3,000 fb^(−1) collected after the High-Luminosity LHC upgrade, the ATLAS Inner Detector will be replaced by the Inner Tracker (ITk) with an increased demand for sensor radiation hardness. Based on the Low Gain Avalanche Detector (LGAD) technology, the High-Granularity Timing Detector (HGTD) will be installed to mitigate against the effect of increased pile-up and enhance vertex separation with a 30 ps timing resolution per track.</p> <p>This thesis presents the electrical characterisation of wafers from the first LGAD batch manufactured by Teledyne e2v, featuring samples with a range of gain layer implant energy and dose. Multiple 1×1 mm^2 LGAD devices were tested in a test beam at the CERN North Area. The results demonstrate excellent hit efficiency (>99%), charge collection (>15 fC), and timing resolution below 20 ps.</p> <p>Electrical measurements of the LGAD sensors after neutron irradiation give acceptor removal coefficients of 7-8×10^(16) cm^2, comparable to other non-carbon enriched LGAD productions. Post-irradiation laser injection tests demonstrated jitter better than 10 ps up to 5×10^(14) 1 MeV n_(eq)cm^(−2), with some devices maintaining charge gain of ∼15 and jitter <25 ps at fluences up to 2×10^(15) 1 MeV n_(eq)cm^(−2). This thesis also includes measurements of the inter-pad distance for multi-pad LGAD devices.</p> <p>The MALTA2 sensor, developed as a monolithic candidate for the outermost layer of the ATLAS ITk, was extensively tested in a test beam with 180 GeV hadrons. The investigation characterised samples up to neutron fluence of 5×10^(15) 1 MeV n_(eq)cm^(−2). Samples produced on the Czochralski (Cz) substrate demonstrated better radiation hardness than those on the epitaxial substrate, particularly with backside metallisation. At 3×10^(15) 1 MeV n_(eq)cm^(−2), MALTA2 Cz samples achieved superior performance with 98% efficiency and 6.3 ns RMS timing resolution.</p> <p>Furthermore, this thesis outlines a preliminary investigation of improved clustering methods that use Time-of-Arrival information to enhance the spatial resolution of the MALTA2 sample by ∼20% and improve the timing resolution by ∼7%. Further steps for generalisation of the method are also discussed.</p> |
| spellingShingle | Silicon diodes Gaži, M Development and characterisation of novel silicon pixel detectors for tracking and timing |
| title | Development and characterisation of novel silicon pixel detectors for tracking and timing |
| title_full | Development and characterisation of novel silicon pixel detectors for tracking and timing |
| title_fullStr | Development and characterisation of novel silicon pixel detectors for tracking and timing |
| title_full_unstemmed | Development and characterisation of novel silicon pixel detectors for tracking and timing |
| title_short | Development and characterisation of novel silicon pixel detectors for tracking and timing |
| title_sort | development and characterisation of novel silicon pixel detectors for tracking and timing |
| topic | Silicon diodes |
| work_keys_str_mv | AT gazim developmentandcharacterisationofnovelsiliconpixeldetectorsfortrackingandtiming |