School of Physics (ETDs)
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Item First principle study of inorganic metal halide perovskites for solar cells application(University of the Witwatersrand, Johannesburg, 2024-08) Maleka, Prettier Morongoa; Maphanga, Regina R.; Ntwaeaborwa, Odireleng MartinAll-inorganic halide perovskites have received significant attention as semiconductor materials due to their outstanding opto-electronic properties, which have achieved power conversion efficiency (PCE) of up to 25% in perovskite solar cells. Their exceptional characteristics include long diffusion lengths for electrons and holes, tuneable band gap, high absorption coefficients, small effective masses, high carrier mobility, and simple reproducible process. Despite these excellent properties, metal halide perovskites have drawbacks that negatively affect the PCE and stability of the perovskite solar cell devices. This study investigated all-inorganic halide perovskite, CsPbI3, by employing the first-principle density functional theory (DFT) method. Firstly, the effect of mixing halides on X-site was investigated to probe the structural stability and opto-electronic properties. The structural, electronic, optical, mechanical and thermodynamics properties of CsPbI3 – xBrx were investigated using three exchange correlation functionals, namely, LDA, GGA-PBE and SCAN meta-GGA. The findings revealed that mixed halide perovskites have an ideal direct energy band gap for suitable photovoltaic applications. For GGA-PBE and SCAN meta GGA exchange correlation functionals, the determined energy band gap ranges from 1.33 eV and 1.877 eV, whereas the LDA band gap ranges between 0.960 eV and 1.137 eV. The electronic band gaps predicted by GGA-PBE and SCAN meta GGA exchange correlation, which offer better precision compared to LDA suggest that Br-doped CsPbI3 – xBrx perovskite is suitable for photons absorption from near-infrared to visible regions of the spectrum. The modification of the band gap is an essential feature of photovoltaics, as it enables the optimization of solar cell performance. In addition, the systems CsPbI3, CsPbI2Br, CsPbIBr2, and CsPbBr3 exhibited exceptional mechanical and thermodynamic stability. Secondly, perovskites that are considered for photovoltaic applications contain toxic element lead (Pb) on the B-site, which limits application of these perovskites in photovoltaic devices. In this study, substitution of toxic Pb with a smaller percentage of selected transition metals was investigated in order to alleviate the toxicity problems. Thus, CsPbI3 doped with 12.5 % concentration of transition metal, Mn, Fe, Ni and Zn was investigated using DFT. The results showed that transition metal doped-CsPbI3 perovskites enhanced the absorption of this material, although they are all indirect band gaps semiconductors. All the materials were found to be mechanically stable. Lastly, cluster expansion which is a method that is capable of describing the concentration dependent thermodynamic properties of materials while maintaining DFT accuracy, was used to predict new (CsPbI/Br)3 structures. The cluster expansion method generated 42 new stable (CsPb)xIyBrz (where x = 1 to 3 and y and z = 1 to 8) structures and these were ranked the meta-stable structures based on their formation enthalpies. Monte Carlo calculations showed that CsPbI0.5Br0.5 composition separates into different phases at 300K, but changes to homogeneous phase at 700 K, suggesting that a different phase of CsPbI3 may exist at higher temperature. Among the 42 predicted structures, randomly selected structures around iodide rich, 50:50 and bromine rich sites were studied further by determining their electronic, optical, mechanical and thermodynamic properties using DFT. The materials possess similar properties as cubic Br doped CsPbI3 perovskites. The mechanical properties of these compounds revealed that they are ductile in nature and mechanically stable. In summary, the thesis present a novel work on introduction of impurities into CsPbI3 perovskite material as well as compositional engineering to alter its electronic and optical properties for solar cells application.Item Search for high-mass resonances in the Zgamma channel and Quality assurance of Scintillation detector modules of Tile Calorimeter Phase-I Upgrade of the ATLAS detector(University of the Witwatersrand, Johannesburg, 2024-09) Mokgatitswane, Gaogalalwe; Ruan, Xifeng; Solovyanov, Oleg; Mellado, BruceThis thesis presents a search for narrow, high-mass resonances decaying to a Z boson and a photon (Zy) in the final state. The analysis utilizes the full Run 2 dataset collected by the ATLAS experiment at the CERN Large Hadron Collider (LHC), corresponding to an integrated luminosity of 140 fb-1 of proton-proton col- lisions at a center-of-mass energy of ps = 13 TeV. The search focuses on a mass range of 220 GeV and 3400 GeV, aiming to identify deviations from the expected background arising from Standard Model processes. A small excess is observed at 250 GeV within the area of interest, with a combined significance of 2.1 standard deviations, indicating the need for further investigation with more data. Upper limits are set on the production cross-section times branching ratio for resonances decaying to Zy across the investigated mass range. When considering spin-0 resonances produced through gluon-gluon fusion, the observed limits at a 95% confidence level range from 65.5 fb to 0.6 fb. For spin-2 resonances produced via gluon-gluon fusion (with quark-antiquark initial states), the limits vary between 77.4 (76.1) fb and 0.6 (0.5) fb. The thesis also highlights the successful Phase-I upgrade of the Tile Calorimeter in the ATLAS detector, ensuring its continued performance. This involved the replacement of degraded Gap-Crack scintillators and Minimum Bias Trigger Scintillators (MBTS) with non-irradiated ones, along-side optimising their geometry, all in preparation for data taking during LHC Run 3. These upgrade endeavors encompassed the design of new Gap-Crack and MBTS counters, including extensions to higher rapidity, the assembly of these counters, their rigorous qualification, and characterization using radioactive sources (90Sr and 137Cs), along with their seamless integration onto the ATLAS detector.Item Evaluation of radiation damage on lutetium-aluminium and gold for practical applications using proton irradiation as a surrogate for neutrons(University of the Witwatersrand, Johannesburg, 2024-10) Temaugee, Samuel Terungwa; Mavunda, Risimati D.; Usman, Iyabo T.An understanding of the interaction of energetic radiations from particles such as protons, neutrons, and photons, with the microstructure of materials is crucial for predicting their bulk morphological response in extreme radiation environments. Exposure to these radiation species could lead to changes in the microstructural properties that, in turn, affect the mechanical and physical properties of the macroscopic matter. This thesis investigated the resilience of materials, specifically Au and Lu-Al, to radiation damage, employing computational simulation methods and experimental techniques. The study aims to provide critical insights into the radiation damage sturdiness of Au and Lu-Al, considering their application in reactor technology and other extreme radiation environments. Monte Carlo-based methods were employed to calculate radiation damage in the samples resulting from neutron and proton irradiation, utilizing MCNP6.2 and SRIM-2013, respectively. The objective was to compare ion beam irradiation with neutrons with a view to utilizing proton irradiation as a surrogate for neutron irradiation. Three different state-of-the-art characterization techniques—X-ray diffraction (XRD), High-Resolution Transmission Electron Microscopy (HRTEM), and Flash Differential Calorimetry(F-DSC)—were employed to evaluate damage in the materials before and after proton irradiation using the CLASS Accelerator at MIT, USA. The results of the study indicated that protons within the energy range 0.1 to 1.0 MeV produced similar types of damage in the materials as would neutrons (spectrum 0< E≤20 MeV at SAFARI reactor), suggesting protons as an alternative to neutron irradiation. Defect characterization in the materials using XRD and HRTEM techniques revealed dislocation loops and lines in both Lu-Al and Au, as well as Stacking Faults Tetrahedra (SFT) in the Au material. These defects with proton irradiation were similar to those observed with neutron irradiation in Au and other aluminum alloys. The estimated defect number density ranged from 0.7 to 4.8 × 1014 m−2, showing an increase with rising displacements per atom (dpa) or proton fluence post-irradiation. Lu-Al exhibited higher defect density values than Au, consistent with Monte Carlo simulations. Furthermore, results from the Flash DSC technique revealed significant changes in the characteristics of the power-temperature profiles (melting curves) of Lu-Al as dpa increased, offering insights into radiation-induced processes such as phase transition and precipitate stability at specific defect annealing temperatures. These findings are crucial for radiation damage studies for the binary alloy and warrant further investigation. The observed microstructural defect densities were relatively high, and prolonged exposure of the materials to higher doses could lead to further changes in microstructural properties, consequently influencing the physical and mechanical properties of the macroscopic material.Item Optimization of Prostate Plan in a Pelvic Prosthesis Phantom(University of the Witwatersrand, Johannesburg, 2024-09) Dumela, Khombo Eunice; Oderinde, Oluwaseyi M.; Usman, IyaboT.Background: An increasing number of elderly prostate cancer patients with high-density material hip prosthesis are referred for external beam Radiotherapy (EBRT). Radiation treatment of pelvis cancer patients with high-density hip prosthesis needs special attention because of the artifacts created in the computed tomography (CT) field of view and the radiotherapy dosimetry challenges. The accuracy of the treatment planning dose calculation algorithms determines the accuracy of the dose delivered to the patient during radiation therapy. However, the most available algorithms do not accurately model the absorption of high-density metals’ scattering properties and underestimate the resulting dose perturbations. Aim: This study aims to optimize the dose distribution of prostate 3D conformal treatment, intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT) in an in-house metallic hip prosthesis phantom. Methods and materials: In this study, an ionization chamber and Gafchromic (EBT3) films were used to physically measure the prostate point dose in an in-house pelvic phantom. The pelvic phantom was irradiated on the Linac with four static fields, namely, (1) anterior field, (2) posterior field, (3) right lateral field passing through the bone of the normal hip and (4) left lateral passing through the hip prosthesis. IMRT and VMATs plans were also generated on the phantom. The phantom was also irradiated with IMRT and VMATs plan. The use of single arc versus two arcs with avoidance sector were also evaluated. The phantom consists of different materials; Nylon-12 (a solid water-equivalent material) to simulate the prostate with a central cavity to accommodate an ionization chamber and film, superflab gel bolus to simulate human soft tissue, dental wax to simulate human soft tissue, bone anatomy for the right hip and a titanium implant to replace the bony structure of the left hip. For the static fields, an in-house pelvic phantom was simulated using the EGSnrc Monte Carlo code, and 6 and 15 MV photon energies were employed as in an experimental setting. The prostate point doses computed by the Treatment Planning System (TPS), measured using ionisation chamber, and Gafchromic EBT3 film were compared with the prostate point doses simulated by Monte Carlo code. Results and discussion: The novel phantom was constructed using superflab gel bolus, Nylon-12, dental wax, pig bone insert and a titanium alloy hip replacement. The radiological equivalence of the superflab gel bolus and dental wax was determined employing linear attenuation coefficients and then compared to an RW3 Solid water phantom. EGSnrc Monte Carlo (MC) code was used in this study. Before using Monte Carlo codes, they need to be validated by comparing the Linear accelerator Monte Carlo simulated dose distribution with the experimental data measured in a Linear accelerator using water and ionization chamber for 6 MV and 15 MV photon beams of different field sizes. The EGSnrc dose distributions were compared with the experimental measurements using a gamma analysis, employing a 2 %/2 mm distance-to-agreement criterion. The EGSnrc Monte Carlo calculated dose distribution agreed well with experimental measurements within 2 %. The MC beam model was then used to compute the dose distribution in an in-house pelvic phantom. The comparison of the measurements between the TPS calculated prostate point dose and ionization chamber for the 6 MV and 15 MV photon beams was: anterior (gantry 0°) 1.8 % and -0.5 %; posterior (gantry 180°) 1.7 % and -0.2 %; left lateral (gantry 90°) 6.3% and 4.2 %; right lateral (gantry 270°) -2.2 % and -2.1 % respectively. Results obtained for Gafchromic EBT3 film measured doses were: anterior 2.3 % and 1.3 %; posterior -0.9 % and 0.2 %, left lateral 4.5 % and 3.5 %; right lateral -2.1 % and -2.5%, for the 6 MV and 15 MV photon beams, respectively. Consequently, results obtained for comparison of TPS, ion chamber and Film with MC simulated doses were: anterior 3.9 %, -2.1 and -1.6% %; posterior 1.8 %, -0.1% and -2.7 %; left lateral -0.2 %, 6.5 % and 4.7 %; right lateral 0.4 %, -2.6% and -2.5 %, for the 6 MV photon beam. And for 15 MV photon beam the results were: anterior 1.9 %, -3.8 and -0.6%; posterior 2.0 %, -2.3 % and -2.2 %; left lateral 0.5 %, 3.7 % and 2.9 %; right lateral 0.4 %, -2.4 % and -2.9 %. Monte Carlo simulations and film measurements have a statistically significant difference of p<0.001, with the film measurements having a higher value than MC simulations except on the left lateral field. Monte Carlo simulations and ionization chamber measurements also show a significant difference of p<0.001, with the ionization chamber having a higher value than the MC simulation, except for the left lateral field passing through the hip prosthesis. The comparison of the measurements between the TPS calculated prostate point dose with ionization chamber and Gafchromic EBT3 film for the 6 MV IMRT plan of the beam passing through the prosthesis was 2.2 % and 3.3%, respectively. While the IMRT plan with avoided beam was 1.9 % and 3.1% for ionization chamber and Gafchromic EBT3 film, respectively. The comparison of the measurements between the TPS calculated prostate point dose for the 6 MV VMAT plan without avoiding for the beam passing through the prosthesis was 1.1 % and 2.2 % for ionization chamber and Gafchromic EBT3 film, respectively. While for VMAT plan with avoided sector as 3.0 % and 4.0% for ionization chamber and Gafchromic EBT3 film, respectively. The test suggested a significant difference of p=0.0001 between the distribution of film measurements and TPS calculated dose. Meanwhile, for ionization chamber measurements and TPS calculated dose; the test indicated a significant difference between ion chamber measurements and TPS calculated dose with a significant level of less than 0.001. in addition, MC simulated dose and TPS calculated dose; the test shows a percentage difference of -0.2 % and 0.5 % for 6 MV and 15 MV photon beams in the lateral field that passes through the prosthesis. The test indicated the significant difference of p=0.001 which is slightly lower compared to the other comparisons. Conclusion: The dual dosimetric pelvic prosthesis phantom is easy to assembly and is more convenient for second dose check for patients with hip prostheses. Through the use of the pelvic phantom, it was possible to measure the prostate point dose using ionization chamber and films. The TPS overestimated the prostate point dose because the treatment planning algorithm could not accurately determine the CT number and the electron density of the prosthesis due to the limitation on the CT scanner. The maximum deviation calculated in this study for TPS, ionization chamber Gafchromic EBT3 films when compared to Monte Carlo simulated dose comes from the lateral fields passing through the prosthesis for both 6 MV and 15 MV photon beams.Item Exploring the 95 GeV Excess with Extended Scalar Models(University of the Witwatersrand, Johannesburg, 2024-10) Mulaudzi, Anza-Tshilidzi; Mellado, Bruce; Kumar, MukeshThis thesis focuses on three interconnected studies investigating the presence of an additional scalar particle, S, of mass around mS ≈ 95 GeV. In the initial study, we explore the notion that an SU(2)L triplet scalar, characterised by a hypercharge Y = 0, could be the origin of the observed 95 GeV di-photon (γγ) excesses seen at ATLAS and CMS. By thoroughly examining its properties, particularly the neutral component, and considering a small mixing angle with the Standard Model Higgs boson, we uncover that this scalar naturally exhibits a substantial branching ratio to γγ. Additionally, we find that its Drell-Yan production via pp → W∗ → HH± adequately accounts for the observed excess. The second study examines how recent measurements of the W bosons’s mass by experiments such as ATLAS and CDF affect the theoretical predictions of the Two Higgs Doublet Model augmented with a Singlet Scalar (2HDM+S) model. It addresses how this model’s parameter space is further constrained by the inclusion of vector-like leptons, focusing on their impact on the muon g − 2 measurements. The third study involves exploring the potential discovery of the aforementioned scalar at future electron-positron colliders. Employing several methodologies, including the recoil mass method in e + e − collisions (e + e − → ZS, where Z → µ + µ − and S → b ¯ b), we leverage a Deep Neural Network to refine the differentiation between the Standard Model background and the targeted signal. The outcomes not only reinforce the potential for detecting the proposed scalar, but also enhance the scientific argument for the establishment of future electron-positron colliders like CEPC, FCC-ee or ILC. Together, these studies contribute valuable insights into the evolving landscape of particle physics.Item Broadband beam shaping(University of the Witwatersrand, Johannesburg, 2024-03) Perumal, Leerin Michaela; Forbes, Andrew; Dudley, AngelaLaser beam shaping is a venerable topic that enjoyed an explosion in activity in the late 1990s with the advent of diffractive optics for arbitrary control of coherent fields. Today, the topic is experiencing a resurgence, fueled in part by the emerging power of tailoring light in all its degrees of freedom, so-called structured light, and in part by the versatility of modern day fabrication and implementation tools. Since its development, structured light has become a priceless tool in various applications such as telecommunication, imaging and microscopy, industrial manufacturing, quantum computing, optical trapping and medical treatments, to name a few. With recent advancements in these various applications, broadband beam shaping (creating structured light with many wavelengths) has become topical as it offers an additional degree of freedom for one to manipulate. In this thesis we look at how to generate broadband light using both digital and physical beam shaping optics. In so doing we provide a method to introduce broadband beam shaping into various applications that may benefit from either the compact size of a physical optic or the dynamic ability of a digital.Item Surface Brillouin scattering studies of high-temperature elasticity(University of the Witwatersrand, Johannesburg, 1999-03) Stoddart, Paul Randall; Comins, J. DarrelA novel technique has been developed for studying the elastic proper ties of opaque solids at high temperatures. The method is based on surface Brillouin scattering (SBS) and has the advantages of being contact-free and non-destructive. The elastic constants can be extracted from SBS measurements of the directional dependence of the surface wave velocities. An optical furnace was designed to provide the special scattering geometry required for these measurements. The technique has been evaluated on silicon and a single-crystal nickel-based superalloy, with measurements up to 800°C and 200°C respectively. Above these temperatures, measurements were precluded by a marked deterioration in the surface quality. The elastic constants for silicon compare favourably with the established ultrasonic values, particularly in terms of the changes as a function of temperature. Additional measurement were performed on silicon at temperatures up to 900°C in order to examine the well-known central mode feature. These results shed light on a major outstanding problem in SBS, because they reveal the presence of a second quasielastic mode that may be associated with scattering from diffusive excitations. Further measurements at high and low temperatures are proposed to confirm the mechanism. Silicon was also used as a test system to clarify certain aspects of the theory and practice of SBS that have not been properly dealt with before, such as the effects of surface anisotropy and of the extended collection aperture. This indicates that SBS provides effective elastic constants for the outer 300 nm of the sample surface and thus may be influenced by surface damage and surface contamination. In the case of the superalloy, the difficulties encountered in gathering data at higher temperatures suggests that modifications to the furnace arrangement are required. The larger relative error in the velocities also created problems in the extraction of the elastic constants. This difficulty was satisfactorily overcome by using the longitudinal threshold in the Lamb shoulder to fix the value of c₁₁. Although the work described here has been limited to temperatures below 900°C, it is clear that SBS provides a powerful method for probing the elastic properties of opaque solids at elevated temperatures.Item Low-temperature electronic transport of metal doped carbon nanotube molecular hybrids and Nitrogen-doped nanocrystalline diamond(University of the Witwatersrand, Johannesburg, 2024-08) Sodisetti, Venkateswara Rao; Bhattacharyya, SomnathThis thesis explores the magnetism and spin-related properties in carbon-based molecular hybrid materials, with a focus on expanding our understanding of low-dimensional carbon structures and their potential electronic applications. The investigation spans from one-dimensional systems, such as carbon nanotubes (CNTs) functionalized with single-molecule magnets (SMMs), to three-dimensional systems like nitrogen-doped ultra nanocrystalline diamond (UNCD). In these carbon structures, electronic transport is intricately tied to microstructural features, such as grain boundaries and impurity clusters, which hold significant potential for the development of all-carbon electronic devices. The research begins with a detailed examination of the chemical functionalization of multi-walled carbon nanotubes (MWCNTs) through controlled acid treatment to achieve precise metal doping. Using Raman spectroscopy and complementary techniques like ICP-MS and ToF-SIMS, we successfully demonstrate how functionalization levels influence the magnetic properties of CNT hybrids loaded with magnetic metals from the lanthanide series (Gd, Tb, Dy). The study reveals that low percentages of metal doping (0.5% to 1.0%) preserve the magnetic bistability of SMMs post-grafting, while higher doping levels lead to complex magnetic behaviors including super paramagnetism, quasi-ferromagnetism, and potential Kondo lattice behavior inCNT-heavy metal systems. We also explore the spin-phonon coupling in Gd-filled double-walled CNTs, where the onset of superparamagnetic properties at low temperatures is coupled with phonon mode stiffening observed via Raman spectroscopy. This enhanced coupling offers promising pathways for developing efficient molecular qubits through the modulation of spin-phonon interactions in one-dimensional systems. The second part of the thesis investigates into the microwave plasma-assisted chemical vapor deposition (MWCVD) growth of nitrogen-doped nanocrystalline diamond (NCD) thin films on different substrates. By pioneering upgrades to the MWCVD system, I was able to achieve reliable growth of high-quality nanocrystalline diamond thin films. Notably, I observed a novel nanostructure, termed Diaphite-a previously unreported feature, in these NCD films, consisting of nanodiamond grains coherently linked with graphene-like rings. This structure, along with the non-equilibrium growth conditions induced by nitrogen doping and secondary nucleation, presents unique polymorphic features in artificially grown diamonds. Detailed low-temperature transport measurements on four different samples—ranging from 7.5% to 20% nitrogen doping—uncovered complex transport phenomena such as 3D weak localization (WL), variable-range hopping (VRH), and unusual magnetoresistance (MR) behavior. In particular, the 7.5% N2-doped UNCD film on quartz exhibited 3D weak localization (WL) at low fields and anti-weak localization (AWL) at higher fields, with distinct magnetoresistance characteristics depending on the direction of the applied magnetic field. The 20% N2-doped films on both quartz and silicon showed more metallic-like behavior, with magneto-resistance characterized by a B1/2 dependence at low temperatures, suggesting an intricate relationship between doping level, microstructure, and electron transport. These findings significantly expand our understanding of the role that microstructural and chemical modifications play in determining the electronic and magnetic properties of carbon-based materials. This work provides a foundational platform for future research into carbon electronics, offering potential breakthroughs in spintronics, molecular transistors, quantum computing, and other advanced electronic applications.Item Digital toolbox for the generation and detection of vectorial structured light(University of the Witwatersrand, Johannesburg, 2023-06) Singh, Keshaan; Dudley, Angela; Forbes, AndrewLight has been an invaluable tool in the development of the modern world, with the myriad of applications increasing along with our degree of control over it. From the development of coherent light sources, to the shaping of amplitude and phase, this development has not ceased for the past half century. The field of structured light, borne out of the necessity and desire for control over light, has been growing steadily in recent years. In the spatial domain, the control over light’s polarization (i.e., the local planes in which the electric and magnetic fields oscillate) has been the most recent avenue of improvement, providing enhancements to a variety of applications ranging form microscopy and communication to materials processing and metrology. This class of light, commonly referred to as vectorial light, often requires specialised equipment in order for its its creation before its numerous benefits can be exploited. These tools often incur high costs and suffer from limitations relating to the diversity of vectorial light they can create, wavelength dependence and slow refresh rates. This thesis follows the development of a series of digital tools for the versatile generation and analysis of vectorial light using low-cost core technologies which can operate at high rates over a broad wavelength range. We follow the development of the generation tool in the context of its application in generating novel accelerating polarization structures, emulating vectorially apertured optics, generating probes to measure birefringence and chirality and creating synthetic spin dynamics. The development of the analysis tool is explored by investigating its application in performing automated digital Stokes polarimetry measurements, completely characterizing the internal degrees of freedom of arbitrary vectorial light and acting as a polarization and wavelength independent wavefront sensor. We then demonstrate how these tools can be used, in conjunction, to investigate the fundamental invariance of vectorial light to perturbing channels and how this invariance can be exploited in a highly robust novel communication scheme. In addition to demonstrating the applicability and versatility of these vectorial light tools, the applications offered a means to highlight areas for the optimization for the design. This culminated in the ongoing prototyping of versatile, fast, broadband devices which operate stably and have a small physical footprint.Item Hunting dark matter with faint radio halos(University of the Witwatersrand, Johannesburg, 2023-10) Sarkis, Michael David; Beck, GeoffThe nature of Dark Matter (DM), the elusive substance that constitutes a significant amount of the total matter in the universe, remains an unsolved problem in modern physics despite a decades-long search effort. One approach to this problem has been to search for faint emission signatures that are produced indirectly from the DM present in large astrophysical structures, and thus infer properties about theoretical DM models from observational data. In recent years, the results from studies that use this type of indirect search have produced stringent constraints on the most popular DM particle candidate parameter spaces, ruling out swathes of viable DM models. These compelling results have been enabled by the arrival of sophisticated interferometric radio telescopes, which are excellent DM hunters due to their high sensitivity and resolution. In this thesis, we focus on the use of the latest data from the MeerKAT radio interferometry telescope, through the first public release of the MeerKAT Galaxy Cluster Legacy Survey, to search for DM emissions in a set of nearby galaxy clusters. Each step of this process, from the creation of theoretical DM emission models to the statistical analysis of the observational data, has been described in detail in this thesis. With this data, we find an almost universal improvement to results found with corresponding modelling scenarios in the literature. Since this work is among the first to use MeerKAT data in astrophysical DM searches, these results present a strong argument for continued work in this field. Another central focus of this thesis is the accurate modelling of the physical processes involved in the production of the DM-induced radio emissions, as the quality of current radio data requires theoretical models that are sufficiently accurate to describe the emission at such high resolutions. One aspect of the modelling that has lacked this accuracy has been the solution to the diffusion-loss equation, which is a crucial factor in determining indirect DM emissions. A new algorithm for solving this equation, which provides higher accuracy and computational efficiency than previous public methods, has thus been developed and presented in this thesis. These aspects of DM indirect detection study will become ever more important as we approach the inauguration of the Square Kilometre Array (SKA), which will provide data with unprecedented potential with which to continue the hunt for DM.