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Modelling muon flux in the Huguenot tunnel using GEANT4
Thesis (MSc)--Stellenbosch University, 2025.
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| Language: | English |
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Stellenbosch : Stellenbosch University
2025
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| _version_ | 1867613800070381568 |
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| access_status_str | Open Access |
| author | Jonker, Stephanus Peterus |
| author2 | Wyngaardt, S. M. |
| author_browse | Jonker, Stephanus Peterus Wyngaardt, S. M. |
| author_facet | Wyngaardt, S. M. Jonker, Stephanus Peterus |
| author_sort | Jonker, Stephanus Peterus |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MSc)--Stellenbosch University, 2025. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/134644 |
| institution | Stellenbosch University (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:41:53.663Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2025 |
| publishDateRange | 2025 |
| publishDateSort | 2025 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/134644 Modelling muon flux in the Huguenot tunnel using GEANT4 Jonker, Stephanus Peterus Wyngaardt, S. M. Stellenbosch University. Faculty of Science. Dept. of Physics. Muons Cosmic rays Monte Carlo method -- Simulation methods Scintillation counters -- Measurement Geological modeling -- Computer simulation Huguenot Tunnel (South Africa) Laboratories -- Technique UCTD Thesis (MSc)--Stellenbosch University, 2025. Jonker, S. P. 2025. Modelling Muon Flux in the Huguenot Tunnel using GEANT4. Unpublished masters thesis. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/2cf2093a-0a36-4eff-927c-0c21baeb11ef ENGLISH ABSTRACT: Currently, the Southern Hemisphere has only one underground laboratory dedicated to low-background physics: the Stawell Underground Physics Laboratory (SUPL) in Australia. If the Paarl African Underground Laboratory (PAUL) is constructed in South Africa’s Huguenot Tunnel, it would become the second such facility in the Southern Hemisphere, helping fill a key geographic gap in the global network of underground labs. PAUL offers an accessible site with a sandstone–granite overburden of up to 800 m, providing natural shielding suitable for rare-event investigations such as dark-matter searches, studies of the biological effects of cosmic radiation, and ultra-low-radioactivity screening. A crucial step for developing PAUL is a reliable characterization of the cosmic-ray muon background, which persists even below ground. This thesis combines field measurements using a portable three-plane plastic scintillator detector with GEANT4 Monte Carlo simulations that incorporate realistic mountain geometry. The results show that the muon flux in the tunnel is suppressed by about a factor of 20 000 compared to open-sky levels, dropping from roughly 46 000 muons per day per detector in the open sky to less than 2 per day near the tunnel centre, beneath the thickest overburden. Two practical laboratory sites were evaluated: Option A measures about 1.2 muons per day per detector, while Option B measures about 2.9. The absolute minimum-flux region cannot be used because it lies beneath a geological fault. This research provides the first site-specific characterization of the muon environment in the Huguenot Tunnel and sets a baseline for PAUL’s design. It shows that further muography will be needed to refine the geological model and flux predictions for the next stage of underground physics in South Africa. AFRIKAANSE OPSOMMING: Tans het die Suidelike Halfrond slegs één ondergrondse laboratorium vir lae agtergrondfisika: die Stawell Underground Physics Laboratory (SUPL) in Australië. As die Paarl African Underground Laboratory (PAUL) in Suid-Afrika se Huguenot tonnel gebou word, sal dit die tweede sulke fasiliteit in die suidelike halfrond wees en help om ’n belangrike geografiese gaping in die wêreldwye netwerk van ondergrondse laboratoriums te vul. PAUL bied ’n maklik toeganklike terrein met ’n sandsteen–graniet oorbedekking van tot ongeveer 800 m dik. Hierdie natuurlike skildlaag maak dit geskik vir navorsing oor rare prosesse, insluitend soektogte na donker materie, studies oor die biologiese effekte van kosmiese straling, en ultra-lae radioaktiwiteit sifting. ’n Vereiste vir die ontwikkeling van PAUL is ’n betroubare karakterisering van die kosmiesestraal muon agtergrond, wat selfs ondergronds steeds gesien kan word. Hierdie tesis kombineer veldmetings met ’n drie-vlak plastiek scintillator detektor, met GEANT4 Monte Carlo simulasies wat realistiese berg geografie en geologiese data uit die SMEC-ingenieursverslag ingesluit het. Die simulasies het die gemete data goed nagemaak en die eerste aaneenlopende muon vloed profiel van die tonnel gelewer, wat die detektor metings aangevul het deur waardes vir onbekende posisies te voorsien. Die resultate toon aan dat die muon vloed in die tonnel met ongeveer ’n faktor van 20 000 onderdruk word in vergelyking met oop lug toestande, en daal van sowat 46 000 muone per dag per detektor in die oop lug tot minder as 2 muone per dag per detektor naby die middel van die tonnel onder die grootste oorbedekking. Twee praktiese laboratoriumposisies is geëvalueer: Opsie A toon ongeveer 1.2 muone per dag per detektor, terwyl Opsie B ongeveer 2.9 muone per dag per detektor toon. Die gebied met die absolute minimum vloed kan nie gebruik word nie omdat dit onder ’n geologiese breuklyn geleë is. Hierdie navorsing bied die eerste terrein spesifieke karakterisering van die muon omgew-ing in die Huguenot tonnel en stel ’n basislyn op vir PAUL se ontwerp. Dit beklemtoon dat muografie nodig sal wees om die geologiese model te verbeter en die voorspellings van muon vloed vir die volgende fase van ondergrondse fisika in Suid-Afrika te verfyn. Masters 2025-12-22T06:34:21Z 2025-12-22T06:34:21Z 2025-12 Thesis https://scholar.sun.ac.za/handle/10019.1/134644 en Stellenbosch University xii, 98 pages : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Muons Cosmic rays Monte Carlo method -- Simulation methods Scintillation counters -- Measurement Geological modeling -- Computer simulation Huguenot Tunnel (South Africa) Laboratories -- Technique UCTD Jonker, Stephanus Peterus Modelling muon flux in the Huguenot tunnel using GEANT4 |
| title | Modelling muon flux in the Huguenot tunnel using GEANT4 |
| title_full | Modelling muon flux in the Huguenot tunnel using GEANT4 |
| title_fullStr | Modelling muon flux in the Huguenot tunnel using GEANT4 |
| title_full_unstemmed | Modelling muon flux in the Huguenot tunnel using GEANT4 |
| title_short | Modelling muon flux in the Huguenot tunnel using GEANT4 |
| title_sort | modelling muon flux in the huguenot tunnel using geant4 |
| topic | Muons Cosmic rays Monte Carlo method -- Simulation methods Scintillation counters -- Measurement Geological modeling -- Computer simulation Huguenot Tunnel (South Africa) Laboratories -- Technique UCTD |
| url | https://scholar.sun.ac.za/handle/10019.1/134644 |
| work_keys_str_mv | AT jonkerstephanuspeterus modellingmuonfluxinthehuguenottunnelusinggeant4 |