During the Apollo 10 and 17 missions NASA astronauts reported that they saw streamers emanating from the surface of the moon. They concluded that the streamers were produced by light scattering from dust particles. The particles are believed to be transported by an ambient electric field. This theorized electric field has never been measured directly, although the electric potential on the surface and above it has. The exact behavior and origin of the electric field is unknown, but has been approximated to be between 1 and 12 V/m. To measure this electrical field a new type of instrument, called Multi Plate Field Mills (MPFM) has been developed. This type of instrument is capable of measuring both the amplitude and directionality of the electrical field. Three of these instruments will be mounted on a 1U CubeSat to be lunched with the PTS mission to the moon scheduled to Q4 2019. In this work the MPFM were characterized. The precision of the instrument for electrical fields applied along the z, y and x axis was found to be 0.6, 1.3, 1.4 (V/m)/(Hz)^(1/2) respectively for measurements in air and 0.14, 0.6, 0.6 (V/m)/(Hz)^(1/2) for measurements in vacuum. This sensitivity outperforms the current state of the art Field Mills and, in addition to that, it provides an assessment of the directionality of the electrical field. / Umeå Lunar Venture

The γ-ray characterizing possibility of the neutron collimated flux monitor (in short, Neutron Camera) at the Mega Ampere Spherical Tokamak (MAST) is explored. Typically used to monitor neutron emission, the Neutron Camera has excellent neutron/γ-ray discrimination properties and thus presents the opportunity to measure spatially and temporally resolved γ-ray emission - a possibility of an additional fusion diagnostics method with already existing equipment. An Online Data Analysis (ODA) code was used to analyze the data on γ-rays from several plasma discharges with similar plasma parameters. A high statistics temporal distribution of the γ-ray emission and a lower statistics spatial distribution were analyzed. However, the low energy resolution and range for the Neutron Camera γ-ray measurements revealed few conclusive results on the origin of the higher energy γ-rays. Detection systems with higher energy resolution and range are suggested for an extensive analysis of γ-ray emission at MAST Upgrade.

After nearly 100 years of particle acceleration, particle accelerator experiments continue providing results within the field of high energy physics. Particle acceleration is used worldwide in practical applications such as radiation therapy and materials science research. Unfortunately, these accelerators are large and expensive. Dielectric Laser Acceleration (DLA) is a promising technique for accelerating particles with high acceleration gradients, without requiring large-scale accelerators. DLA utilizes the electric field of a high energy laser to accelerate electrons in the proximity of a nanostructured dielectric surface.The aim of this project was limited to laser beam routing and imaging techniques for a DLA experiment. The goal was to design the laser beam pathway between the laser and the dielectric sample, and testing a proposed imaging system for aiming the laser. This goal was achieved in a test setup using a low-energy laser. In the main setup including a femtosecond laser, the result indicated lack of focus. For a full experimental setup, a correction of this focus is essential and the beam path would need to be combined with a Scanning Electron Microscope (SEM) as an electron source.

The new millennium has seen revolutionary advances in photonsource technology. As the newly constructed synchrotron facilityMAX IV in Lund, Sweden, pushes brilliance toward what isphysically possible, low-yield spectroscopic techniques, such asresonant inelastic X-ray scattering (RIXS), open new doors inmolecular and condensed matter research. The VERITAS beamline atMAX IV is designed for high-resolution vibrational RIXS on gases.X-rays interact with flowing molecules inside a window-cappedcell, but the radiation intensity is expected to be large enoughto damage the windows, and cause build-up of photochemicalproducts, which lowers transmission. To address these issues, anovel gas cell design is presented, wherein the distance betweensample gas and window is increased by using a flowing heliumbuffer. The main challenge is maintaining a steep sample gasconcentration gradient within the cell, and to that end, gas flowswere simulated on various geometries by using the finite elementmethod to solve the Navier-Stokes equations. Results were used toconstruct a prototype, and confocal Raman microscopy was used forconcentration characterization. Preliminary measurements revealeda uniform sample gas distribution, and the technique proved to beinefficient for wide scanning of parameter values. This suggeststhat a supplementary experiment is required to find roughestimates of good parameter values, which can then be followed upwith new Raman measurements for fine-tuning of the properparameter space. Real-time visualization of the sample gas flow,using a visible gas under an optical microscope, is one candidatefor this supplementary experiment.

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To study electron emissions and dark currents in the accelerating structures in particle colliders, a test facility with a spectrometer has been constructed at CERN. This spectrometer has been simulated in the C++ toolkit GEANT4 and in this project the simulation has been improved to handle new realistic input data of the emitted electrons. The goal was to find relations between where the electrons are emitted inside the accelerating structure and the energy or position of the particles measured by the spectrometer. The result was that there is a linear relation between the initial position of the electrons and the width in the positions of the particles measured by the spectrometer. It also appears to be a relations between energy the emitted electrons get in the accelerating structure, which is related to the position, and the energy they deposit in the spectrometer. Further studies where the simulations are compared with real measurement data are required to determine whether these relations are true or not, find better reliability in the relations and get a better understanding of the phenomena.

In the planned linear accelerator called Compact Linear Collider, CLIC, electrons and positrons will be accelerated to velocities near the speed of light. A limiting factor in accelerating structures are vacuum breakdowns, which are electrical discharges from a surface as a result of a large electric field being applied. In the preparatory studies for the CLIC, Uppsala University in collaboration with The European Organization for Nuclear Research, CERN, is building a DC Spark system to analyze vacuum breakdowns. This system containing large planar electrodes will be cooled down all the way down to around 4 K in order to limit the rate of wich vacuum breakdowns happen. When cooling a system like this, which consists of different components made of different materials there is the question of how the system will be affected. The objective of this project is to investigate how the cooling will affect the stability in terms of stresses and to analyze the cool down time of the system. Another goal is to make a material recommendation for a few parts based on the results. This will be done by simulating the cooling in COMSOL Multiphysics, which is a program that uses finite element analysis to solve complex problems where different branches of physics interact. The conclusion is that the system will most likely be stable as it is and there is no need to redesign it. The choice of recommended material is alumina with the reason being it should cause the least stress and the smallest gap between the electrodes when the cooling is done. There was no big difference in the cool down time between the materials. Further studies and simulations on the system is also recommended since there are many factors not taken into consideration in this study.

While holding a firm position in popular culture and science fiction, Dark Matter (DM) is nonetheless a highly relevant topic at the forefront of modern particle physics. We study the applicability of characterizing DM particle candidates SUSY neutralino and sneutrino using Deep Learning (DL) methods. We focus on the monojet and mono-Z signatures and the emergence of missing transverse energy as the result of the undetectable DM candidates. Based on kinematic distributions of outgoing particles as input, a DM candidate classifier is built for each signature, along with a DM mass regressor. The DM candidate classifier obtained near perfect accuracy of 0.995 for the monojet, and 0.978 for mono-Z signature. The monojet and mono-Z mass regressors achieved a Mean Absolute Percentage Error (MAPE) of 17.9 % and 8.5 % respectively. Furthermore, we discuss both the shortcomings and simplification that our choice of model implied, as well as an interpretation of the results. Finally, we debate the prospects of DL in the discovery of new physics and it's use in experiments.

Artificial intelligence (AI) and deep learning have made a full impact on society the last decades, including the realm of particle physics. This thesis explores whether a neural network, a deep learning program mimicking the biological brain, can be used to reject noise in real time at the Radio Neutrino Observatory in Greenland (RNO-G). RNO-G aims to detect radio waves in the ice cape of Greenland, induced by ultra high energy neutrinos ($>10^{18}$ eV). Due to the low flux of neutrinos at these energies, it is desired to increase the sensititivty of RNO-G by lowering the trigger threshold as much as possible. However, lowering the threshold is currently limited by unavoidable thermal noise fluctuations that would otherwise saturate the detector. Previous research has shown that a neural network could be used on a similar neutrino detector, ARIANNA, to reject thermal noise in real time, thus making it possible to lower the trigger threshold below the noise floor. This thesis aims to do the same for RNO-G.

The Large Hadron Collider at CERN is scheduled to undergo upgrades in 2026-2028 to significantly increase its luminosity. These upgrades, while providing the experiments with a higher collision rate, pose a number of challenges to the design of the hardware and software in the detectors. The Tile Calorimeter (a scintillating sampling calorimeter read out by photomultiplier tubes) at the ATLAS experiment will have its read-out electronics completely replaced to enable performance and reliability improvements.  Advances in electronics, new requirements due to the luminosity upgrade as well as lessons learned from the current readout scheme drove development with the goals to partition the readout into small independent units with full granularity readout and a robust mitigation strategy for radiation induced errors. To verify the functionality of the new system while retaining backward compatibility a "Demonstrator'' has been developed to emulate the current functionality while using new and improved hardware. The board responsible for managing digitized calorimeter data and communicating with the off-detector electronics, called the DaughterBoard, is the main focus of this thesis. It has two electrically isolated sides for redundancy where each side consists of voltage regulators, two optical transceivers, a GigaBit transceiver chip (for clocking and configuration) and a Kintex FPGA for data processing. In addition to data management and transmission, the FPGA (and every other component) needs to be able to withstand the effects of radiation both in terms of total dose (ionization and displacement damage) and due to single event effects. The DaughterBoard was developed with this in mind and has undergone several radiation tests during its development to verify reliability and fault tolerance. / CERN