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Proton or heavy ion beams are a very attractive and promising tool in cancer therapy. They offer much localised and better controlled dose distributions in comparison to X-rays, thus, decreasing damage sustained by healthy tissue. Diagnostics of these beams is particularly interesting as interference with the beam, especially in the case of the ocular treatment, leads to a significant degradation of essential parameters of beam, therefore, non-interceptive methods of monitoring are preferred. In this work, a novel method of a proton beam current monitor was devised, relaying on non-invasive measurements, investigating the proton beam halo region. The method required adaptation of the LHCb VELO detector to allow its operation as a stand-alone device. The performance of the detector was tested in conjunction with a dedicated Faraday Cup, optimised to suit the clinical proton beam characteristics at the Clatterbridge Cancer Centre (CCC). To perform theoretical predictions of the proposed monitor, auxiliary measurements were completed that involved other instrumentation such as scintillating screens. They were used in the beam profile measurements that sourced information used afterwards to create a model of the existing beamline, which was used to find the extent of and nature of the beam halo extent. The thesis presents results of theoretical studies and modelling of different parts of the experimental set-up leading to the final design of the mentioned monitor, followed by a first successful run with a proton beam at CCC. A discussion on the outcomes of data analysis is presented with indication for possible future development of the method. Although the monitor was prepared and tested with a 60 MeV proton beam, the instrumentation can used with higher energy hadron therapy beams, including other particle species than protons once additional adaptation to their properties has been performed.

Quantum chromodynamics, the quantum field theory that describes the strong interaction, demonstrates a property known as asymptotic freedom which weakens the strong coupling constant αs at high energies or short distances. The measurement of particles containing heavy quarks, i.e. charm and beauty, in high-energy particle collisions is a stringent test of the theory of quantum chromodynamics in the regime where αs is small. In addition, asymptotic freedom leads to a phase transition of nuclear matter at high temperatures or energy densities to a phase known as the Quark-Gluon Plasma, where quarks and gluons are deconfined, and this state of matter can be studied in relativistic heavy-ion collisions. Particles containing heavy quarks, i.e. charm and beauty, have been proposed as probes of the properties of the Quark Gluon Plasma, where the measure- ment of mesons and baryons can offer insight into the transport properties of the medium and mechanisms related to the formation of hadrons during the transition back to ‘confined’ quark states. Proton-proton and proton- lead collisions offer a crucial benchmark for these measurements, and can also reveal important insights into particle production and interaction mechanisms. The goal of this thesis is to investigate the production of the charmed baryon Λc+ in high-energy particle collisions with the ALICE detector at the Large Hadron Collider. The measurements presented will test pre- dictions utilising perturbative (small αs) and non-perturbative (large αs) methods, will test possible cold-nuclear-matter modifications of the Λc+ yield in proton-lead collisions, and will set the stage for future measure- ments in lead-lead collisions. The measurements are carried out by recon- structing the hadronic decay channel Λc+ → pK−π+, making selections on its decay topology, extracting the signal via an invariant mass analysis, and finally correcting for its selection and reconstruction efficiency. A multivariate technique (Boosted Decision Trees) has been developed and is utilised in order to improve the signal extraction by optimally com- bining discriminating variables related to the Λc+ decay topology. This technique has also been investigated as a possible approach to measuring the Λc+ baryon in lead-lead collisions in the future, after the upgrade of the ALICE Inner Tracking System will make this measurement possible. The transverse momentum dependence of the Λc+ baryon production cross section has been measured in proton-proton collisions at a centre-of-mass energy of 7 TeV and proton-lead collisions at a centre-of-mass energy per nucleon-nucleon collision of 5.02 TeV, in the transverse momentum range 2 < pT < 12 GeV/c, and is shown to be under-predicted by theoretical calculations. The baryon-to-meson ratio Λc+ /D0 has been measured to be consistent in proton-proton collisions and proton-lead collisions and under-predicted by theoretical calculations. The nuclear modification fac- tor RpPb is measured to be consistent with unity and in agreement with the D meson RpPb, indicating no significant modification of the Λc+ yield in proton-lead collisions with respect to proton-proton collisions within the experimental uncertainties. Finally, Boosted Decision Trees have been shown to significantly improve the statistical precision with which the measurement of the Λc+ baryon can be made in lead-lead collisions with the ALICE detector in the future.

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Dielectric laser-driven accelerators (DLAs) utilizing the large electric fields from commercial laser systems to accelerate particles with high gradients - in the range of GV/m - have the potential to dramatically reduce the size and cost of future particle accelerators. Dual-gratings are one of the candidates for DLAs. They can be mass-produced using currently-available nanofabrication techniques, due to their simpler structural geometry compared to other types of DLA. So far, dual-grating structures have experimentally demonstrated accelerating gradients of 300 MV/m, 690 MV/m, and 1.8 GV/m for relativistic electron acceleration and gradients of 220 MV/m and 370 MV/m for non-relativistic electron acceleration. These demonstrations pave the way for implementing an on-chip particle accelerator in the future. This thesis presents detailed studies of dual-grating DLAs, including geometry optimizations, beam quality and energy efficiency studies, wakefield and particle-in-cell (PIC) simulations, as well as the fabrication and experimental preparations beyond the current state-of-the-art DLAs. In order to identify the optimum geometry, various numerical studies are carried out using the CST and VSim simulation codes, to maximize the accelerating factor and the accelerating efficiency for dual-grating structures, and results from both codes are compared. The beam parameters of the future Compact Linear Accelerator for Research and Applications (CLARA) facility are then used to load an electron bunch into an optimized 100-period dual-grating structure, where it interacts with a realistic laser pulse. The emittance, energy spread, and loaded accelerating gradient for modulated electrons are then analysed in detail. Results from simulations show that an accelerating gradient of up to 1.15 GV/m, with an extremely small emittance growth, 3.6%, can be expected. Two new kinds of schemes are also investigated in this thesis to improve the electron energy efficiency for dual-grating DLAs. One is to introduce a Bragg reflector, which can boost the accelerating field to generate a 70% higher energy gain compared to bare dual-grating structures, from PIC simulations. As a second scheme, pulse-front-tilted operation for the laser beam is proposed, to extend the interaction length and thereby increase the greater energy gain by more than 138% compared to normal laser illumination, from PIC simulations. When both schemes are combined together for dual-grating DLAs, the energy gain generated is increased by 254% compared to normal laser illumination on bare dual-gratings. This thesis also presents numerical studies for a THz-driven dual-grating structure to accelerate electrons, including geometry optimizations and detailed studies of wakefield and THz-bunch interaction. Such scaled structures can be fabricated using conventional machining techniques, which makes future demonstrations easier than for DLAs. Finally, the fabrication techniques for laser-driven dual-grating structures are studied, with researchers in Paul Scherrer Institut (PSI). A dual-grating structure with a channel depth of 7.6 μm and excellent alignment has been successfully fabricated using a monolithic method. The preliminary experimental studies carried out using the electron beam from the Swiss FEL facility are also presented in this thesis, and the future challenges for dual-grating DLAs are discussed.

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Beam diagnostics systems are essential constituents of any particle accelerator; they reveal the properties of a beam and how it behaves in the machine. This includes: synchrotron light sources and free-electron lasers; high energy accelerators for particle physics experiments; high-intensity hadron accelerators for the generation of exotic beams and spallation sources; much smaller accelerator facilities where cooled beams of specific (exotic) particles are provided for precision experiments and fundamental Physics studies. Without an appropriate set of diagnostic elements, it would simply be impossible to operate any accelerator complex, let alone optimise its performance. This thesis covers investigations into two different beam diagnostics methods. The first part describes work carried out at RIKEN Radioactive Isotope Beam Factory (RIBF) in Japan during October 2013-January 2016. It deals with the development of an online emittance monitor for an ECR ion source that produces low energy beams of various species ranging from protons up to heavier ions such as krypton. The monitor was initially based on an earlier RIKEN prototype which had insufficient performance. After four design iterations and multiple experimental tests the final prototype was integrated at the ion source and experimental measurements were carried out. One of the major challenges was to identify suitable scintillating materials that do not heavily degrade after irradiation with low energy ion beams. Additionally to the emittance monitor, work also focused on optimising the ECR ion source and increasing the beam current by improving the ion extraction. The first and the last year of this PhD were spent at the Cockcroft Institute, UK. Work done there is presented in the second part of this thesis which delves into a non-invasive real-time beam profile monitor based on a supersonic gas jet. This monitor was originally conceived and developed by at the Cockcroft Institute but was never operated successfully in the gas jet mode but only as a residual gas monitor. During this PhD, the monitor was commissioned in gas jet mode, alignment issues that prevented previous operation were identified and addressed and the first experimental results were obtained. Moreover, the vacuum dynamics of the system were explored and additional diagnostics instrumentation for the measurement of the gas jet properties was developed and installed. This thesis presents the design of both beam diagnostics methods, for transverse emittance and transverse profile determination, results from measurements with various beam species and a detailed analysis of their performance. Furthermore, it highlights the challenges of the design, integration, optimisation and real time operation for both instruments.

This thesis presents the results of two separate collinear laser spectroscopy investigations; one of proton-neutron pairing correlations in the odd-odd self-conjugate nucleus 42Sc, and the other investigating the charge radii of neutron-rich Y isotopes and the sudden onset of nuclear deformation in the Z~40, N~60 region of the nuclear chart. For the first time, the 42g,42mSc isomer shift, and corresponding change in mean-square charge radius, has been studied via collinear laser spectroscopy at IGISOL IV. The result for the change in mean-square charge radius supports the qualitative prediction given by the intuitive picture of proton-neutron pairing, in which the nuclear charge radius should be greater for an I=0, T=1 nuclear state than an I≠0, T=0 state. This result is also, qualitatively speaking at least, in agreement with the results of previous proton-neutron pairing studies, namely studies of the charge radii of 38g,38mK and 50g,50mMn. In addition to this, new values of the atomic factors for the mass and field shift, F and M, have allowed for a recalibration of the Sc charge radii measured previously on the same atomic transition as used here. Spectroscopy has been performed on radioactive Y2+ ions for the first time. The motivation for this was to recalibrate previously measured charge radii for 86-90,92-102Y and isomeric states in 87-90,93,96,98Y, which were measured on the 363.3nm 5s2 S0 → 4d5p 1P1 transition occurring in the Y+ ion. The complexity of this transition hindered the ability to reliably calculate the atomic mass and field shift factors, which are necessary for extraction of nuclear charge radii.