Charged particle accelerators often have strict requirements on the beam energy, and timing to calibrate, or control background processes. Longitudinal Phase Space Tomography is a technique developed in 1987 to visualize the time, and energy coordinates of a beam. With non-invasive detectors, the beam can be visualized at any point during operation of a synchrotron. With the progress of computing power over the last 27 years, it is now possible to compute tomographic reconstructions in real time accelerator operations for many bunches around the accelerator ring. This thesis describes a real-time, multi-bunch tomography system developed and implemented in Fermilab's Main Injector and Recycler Rings, and a study of bunch growth when crossing transition. Implications of these studies for high intensity operation of the Fermilab accelerators are presented. / text

A particle accelerator simulation which straddles the gap between multi-particle and moment codes is derived. The hybrid approach represents the beam using macro-particles which contain discrete longitudinal coordinates and transverse second moments. The discretization scheme for the macro-particles is derived using variational principles, as a natural extension of well known variational approaches. This variational discretization allows for exact transverse emittance conservation. The electrostatic self-potential is discrete in the longitudinal direction and solved semi-analytically in the transverse direction using integrated Green’s functions. The algorithm is implemented and tested against both a moment and multi-particle code. / Graduate

The International Linear Collider (ILC) aims to collide electrons and positrons with a centre of mass energy of 500GeV and a luminosity of 2×10³⁴ cm⁻² s⁻¹. To achieve this luminosity, the nominal final emittance of the electron and positron beams have to be below 10μm.rad horizontally and 0.04μm.rad vertically. To prevent the emittance from becoming too large, the main linacs will require alignment at an unprecedented level. The ILC main linacs will be aligned with respect to a reference network which runs along the entire length of the tunnel. The Linear Collider Alignment and Survey (LiCAS) Rapid Tunnel Reference Surveyor (RTRS) is the prototype of a device proposed to survey the ILC reference network. The LiCAS RTRS has several measurement systems; its Frequency Scanning Interferometry (FSI) measurement system is studied in this thesis. The FSI system has three distinct sub-systems: the reference interferometers, the external FSI measurement system and the internal FSI measurement system. The errors on the length of the reference interferometers are shown to be of the order of 1.1μm (0.3ppm). The external FSI measurement system is shown to measure distances close to 0.42m with errors of ±1.9μm stat ±0.16μm syst and the internal FSI measurement system is shown to measure distances close to 4.2m with errors of ±0.24μm stat ±1.6μm syst. A survey of the ILC reference network using laser trackers is simulated without taking account of systematic measurement errors from refraction in the tunnel air. The simulated networks are used to misalign the simulated accelerators in Dispersion Matched Steering (DMS) simulations. The DMS simulations show that only 30% of the simulated accelerators produce an acceptable final corrected vertical emittance. It is further shown that the introduction of long range distance measurements between primary reference markers (PRMs) using GPS, reduces the long range error growth in the network, and that 95% of simulated accelerators give acceptable performance. A simplified network simulation model, which is capable of simulating reference networks surveyed by conventional and novel devices, is produced and compares favorably to full simulations.

Following the discovery of the Higgs-like boson at the Large Hadron Collider, there is demand for precision measurements on recent findings. The Compact Linear Collider, CLIC, is a candidate for a future linear electron-positron collider for such precision measurements. In CLIC, the beams will be brought to collisions in the multi-TeV regime through high gradient acceleration with high frequency RF power. A high intensity electron beam, the so-called drive beam, will serve as the power source for the main beam, as the drive beam is decelerated in special structures, from which power is extracted and transfered to the main beam. When the drive beam is decelerated the beam quality deteriorates and the momentum spread increases, which makes the beam transport challenging. Dedicated diagnostics to monitor the momentum profile along each bunch train and transverse profile diagnostics will be needed to guarantee the reliability of the decelerator and consequently the power source of the main beam acceleration. A test facility, CTF3, has been constructed at CERN to validate key technical aspects of the CLIC concept. The beam quality in the decelerator will be investigated in the test beam line, TBL, where several power extraction structures reduce the drive beam energy by up to 55%. At the same time, the single-bunch rms energy spread grows from the initial value of 1% to almost 6%. To monitor the parameters of such a beam is challenging but crucial for the optimization of the beamline. In this thesis we report on progress made on adapting generally used methods for beam profile measurements to the demanding conditions of a wide momentum profile. Two detector technologies are used for measuring transverse profile and momentum profile and we discuss the performance of these instruments, in the view of the large momentum spread and with the outlook towards equivalent beam profile monitors in the CLIC decelerator.

An overview of the beam diagnostics for the laser wakefield acceleration project at the Texas Petawatt Laser facility is presented. In this experiment, short and intense laser pulses of 165 fs and up to 190 J will be used to accelerate electrons up to the GeV energy range using laser wakefield acceleration. The density variation of the plasma generated in a helium gas cell will be measured with different optical detection systems such as frequency domain holography. Spectra of the transmitted laser beam and optical transition radiation will yield information about the energy transfer to the plasma and the energy of the electrons, respectively. In addition, a calorimeter will measure accelerated electron energies. Prior to the final experiment, preliminary frequency shift measurements and simulations on optical transition radiation were performed. / text

This thesis describes the design a novel type of particle accelerator for charged particle therapy. The accelerator is called a non-scaling, Fixed Field Alternating Gradient (ns-FFAG) accelerator, and will accelerate both protons and carbon ions to energies required for clinical use. The work is undertaken as part of the PAMELA project. An existing design for a ns-FFAG is taken as a starting point and analysed in terms of its ability to suit the charged particle therapy application. It is found that this design is particularly sensitive to alignment errors and would be unable to accelerate protons and carbon ions at the proposed acceleration rate due to betatron resonance crossing phenomena. To overcome this issue, a new type of non-linear ns-FFAG is developed which avoids resonance crossing and meets the requirements provided by clinical considerations. Two accelerating rings are required, one for protons up to 250 MeV and fully stripped carbon ions to 68 MeV/u, the other to accelerate the carbon ions up to 400-430 MeV/u. Detailed studies are undertaken to show that this new type of accelerator is suitable for the application. An alignment accuracy of 50 micrometers will not have a detrimental effect on the beam and the dynamic aperture for most lattice configurations is found to be greater than 50 pi.mm.mrad normalised in both the horizontal and vertical plane. Verification of the simulation code used in the PAMELA lattice design is carried out using experimental results from EMMA, the world's first ns-FFAG for 10-20 MeV electrons built at Daresbury Laboratory, UK. Finally, it is shown that the described lattice can translate into realistic designs for the individual components of the accelerator. The integration of these components into the PAMELA facility is discussed.

The developments of nuclear medicine lead to an increasing demand for the production of radioisotopes with suitable nuclear and chemical properties. Furthermore, from the literature it is evident that the production of radioisotopes using charged-particle accelerators instead of nuclear reactors is gaining increasing popularity. The main advantages of producing medical isotopes with accelerators are carrier free radionuclides of short lived isotopes, improved handling, reduction of the radioactive waste, and lower cost of isotope fabrication. Proton-rich isotopes are the result of nuclear interactions between enriched stable isotopes and energetic protons. An interesting observation is that during the production of proton-rich isotopes, fast and intermediately fast neutrons from nuclear reactions such as (p,xn) are also produced as a by-product in the nuclear reactions. This observation suggests that it is perhaps possible to use these neutrons to activate secondary targets for the production of neutron-rich isotopes. The study of secondary radioisotope production with fast neutrons from (p,xn) reactions using a particle accelerator is the main goal of the research in this thesis.

Particle accelerators produce beams of high-energy particles, which are used for both fundamental and applied scientific research and are critical to the development of accelerator driven sub-critical reactor systems. An effective magnetic shield is very important to achieve higher quality factor (Qo) of the cryomodule of a particle accelerator. The allowed value of field inside the cavity due to all external fields (particularly the Earth’s magnetic field) is ~15 mG or less. The goal of this PhD dissertation is to comprehensively study the magnetic properties of commonly used magnetic shielding materials at both cryogenic and room temperatures. This knowledge can be used for the enhanced design of magnetic shields of cryomodes (CM) in particle accelerators. To this end, we first studied the temperature dependent magnetization behavior (M-H curves) of Amumetal and A4K under different annealing and deformation conditions. This characterized the effect of stress or deformation induced during the manufacturing processes and subsequent restoration of high permeability with appropriate heat treatment. Next, an energy based stochastic model for temperature dependent anhysteretic magnetization behavior of ferromagnetic materials was proposed and benchmarked against experimental data. We show that this model is able to simulate and explain the magnetic behavior of as rolled, deformed and annealed amumetal and A4K over a large range of temperatures. The experimental results for permeability are then used in a finite element model (FEM) in COMSOL to evaluate the shielding effectiveness of multiple shield designs at room temperature as well as cryogenic temperature. This work could serve as a guideline for future design, development and fabrication of magnetic shields of CMs.

No presente trabalho medimos e analisamos distribuições angulares para o processo de espalhamento elástico do núcleo radioativo de 12B em alvo de 58Ni. As medidas foram realizadas nas energias de Elab=30.0 e 33.0 MeV no laboratório do acelerador Pelletron. Essas energias são próximas a barreira Coulombiana (VB=28.0 MeV) para esse sistema. Para a produção do feixe radioativo de 12B utilizamos o sistema RIBRAS instalado nesse laboratório. As distribuições angulares foram analisadas com o modelo ótico, utilizando potenciais de Woods-Saxon e Potencial de São Paulo. Para uma interpretação física mais consistente e um estudo da influência de outros canais de reação no espalhamento elástico analisamos também considerando o método de canais acoplados. Considerando o acoplamento dos canais de espalhamento inelásticos, reorientação e spin-órbita pudemos descrever a distribuição angular na energia de 30.0 MeV. No entanto esses canais não foram suficientes para descrever a distribuição angular na energia de 33.0 MeV, indicando que outros canais como de transferência e/ou break-up possam ser importes. A partir da análise das distribuições angulares com modelo ótico obtivemos também a seção de choque total de reação. Essas seções de choque foram comparadas com a de outros sistemas utilizando métodos de redução, indicando que o projétil 12B segue uma sistemática intermediária entre núcleos fortemente ligados e fracamente ligados. Finalmente, discutimos a sistemática dos resultados de canais acoplados para o espalhamento elásticos dos isótopos de Boro 8,10,11,12B no alvo 58Ni em termos da configuração de clusters dos projéteis. / In the present work we measure and analyzed angular distributions for the process of elastic scattering of the radioactive nucleus of 12B in a target of 58Ni. The measurements were performed in the energies of Elab = 30.0 and 33.0 MeV in the Pelletron accelerator laboratory. These energies are close to the Colombian barrier (VB = 28.0 MeV) for this system. For the production of the radioactive beam of 12B we used the RIBRAS system installed in this laboratory. The angular distributions were analyzed with the optical model, using potentials of Woods-Saxon and Potential of São Paulo. For a more consistent physical interpretation and a study of the influence of other reaction channels in the elastic scattering we also analyze the coupled channel method. Considering the coupling of the inelastic scattering channels, reorientation and spin-orbit we could describe the angular distribution in the energy of 30.0 MeV. However, these channels were not enough to describe the angular distribution in the energy of 33.0 MeV, indicating that other channels as transfer and / or break-up can be amounts. From the analysis of the angular distributions with optical model we also obtained the section of total reaction shock. These cross sections were compared with those of other systems using reduction methods, indicating that projectile 12B follows a systematic intermediate between tightly bound and weakly bonded cores. Finally, we discuss the systematics of the results of elastic scattering channels of the Boron isotopes 8,10,11,12B in the 58Ni target in terms of the cluster configuration of the projectiles.

Foram determinadas de maneira absoluta seções de choque duplamente diferenciais de produção de bremsstrahlung, para elétrons com energia cinética de 20, 50, 75 e 100~keV, nos elementos C, Al, Ag, Te, Ta e Au, e nos ângulos de emissão dos fótons $35^{\\mathrm}$, $90^{\\mathrm}$ e $131^{\\mathrm}$. As medidas foram realizadas na linha de feixe de baixa energia do Acelerador Microtron, do Instituto de Física da Universidade de São Paulo, em um arranjo que contou com três detetores de Ge hiperpuro, dois planares e um coaxial. Os alvos finos foram confeccionados pela técnica de deposição física de vapores, enquanto suas espessuras foram caracterizadas a partir da espectrometria de retroespalhamento de Rutherford. Foi desenvolvido um modelo analítico para descrever a função reposta de detetores de Ge, que permitiu a deconvolução dos espectros de bremsstrahlung entre os 12~keV e o ponto de máxima transferência de energia, com uma resolução de 1~keV. As seções de choque obtidas apresentam uma incerteza relativa entre 3\\% e 5\\%, e foram comparadas com os cálculos teóricos que constituem o estado da arte na temática, e com os poucos dados experimentais encontrados na literatura. / Bremsstrahlung doubly dierential cross sections were absolutely determined for electrons with kinetic energies of 20, 50, 75 and 100 keV, in the elements C, Al, Ag, Te, Ta e Au, and the photon emission angles of 35o, 90o and 131o. The measurements were performed at the low energy beam line of the S~ao Paulo Microtron Accelerator, using three high purity Ge detectors: two planar and one coaxial. Thin targets were obtained by the Physical Vapor Deposition technique, and their thicknesses were characterized through Rutherford Backscattering Spectroscopy. An analytical model was developed to describe the response function of Ge detectors, which allowed to unfold the bremsstrahlung spectra between 12 keV and the maximum energy transfer point, with an energetic resolution of 1 keV. The obtained cross sections present relative uncertainties between 3% and 5%. These results were compared with the higher accurate theoretical calculations and also with the experimental reports found in literature.