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.

Particle ingestion in gas turbine applications can be detrimental to performance and pose significant safety concerns. Areas of high sand concentration are hazardous to aircraft, requiring precautions like routine inspections and maintenance. The engine failure modes are dependent on particle composition, concentration, and size. Particles containing certain minerals tend to melt and stick to turbine blades, which is known as glazing. Alternatively, particles may erode blades from repeated collisions, or they may fill cooling passage holes. Therefore, it is necessary to develop systems that identify these parameters as particles are ingested. This thesis introduces three separate systems responsible for collecting sand concentration, size distribution, and material composition of sand. A particle visualization technique (ParVis), developed at Virginia Tech, was used to validate two sensors developed by commercial partners. One sensor measures particle size and velocity with a method similar to Laser Doppler Velocimetry (LDV). The second sensor measures particle composition with X-Ray Fluorescence (XRF) by physically sampling particles in a flow. There has been little research on applying XRF to moving particles, so experimental data were collected to demonstrate the effectiveness of the sensor. Detection comparisons between two particle types showed promising outcomes for the XRF. Meanwhile, the ParVis technique was iterated to overcome previous limitations and implemented into the testing process to provide particle concentration measurements. Particularly, improvements led to increased accuracy and reliability of the method such as reducing variance in concentration approximations. / Master of Science / Aircraft are constantly ingesting particles into their engines. Those operating in dusty environments are at higher risks of engine failure because more particles are ingested, which cause damage in several ways. As engine manufacturers push the turbine operating temperatures higher for efficiency and emissions, sand particles reach melting temperatures and stick to turbine blades, which results in overheating. Because of the potential risks to life, sand ingestion research continues to provide solutions for improving aircraft safety. This study explores the capabilities of new sensors to quantify characteristics of ingested particles, including the concentration, size distribution, and material composition of sand. An illumination technique for measuring sand concentration from particle imaging was developed at Virginia Tech. The technique was iterated to overcome previous limitations and improve its reliability during this study. It provides a more accurate depiction of the testing conditions that can be used to diagnose and calibrate sensors. In this case, two sensors issued by Creare were tested, one of which measures size and particle velocity, while the other measures sand composition. The first sensor relies on non-intrusive optical measurements and can be mounted directly to an engine inlet. The second sensor collects particles from the inlet flow and applies X-Ray Fluorescence (XRF) to the moving particles. There has been little research on applying XRF to a flow of particles, so experimental data were critical to demonstrate the effectiveness of the sensor. technique was iterated to overcome previous limitations and implemented into the testing process to provide particle concentration measurements.

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.

Any future linear collider requires a beam stabilisation system at the interaction point to the to maintain luminosities. This thesis details the development of prototypes of three such systems based at the Accelerator Test Facility 2 (ATF2) at KEK, Japan. The upstream feedback system utilises two stripline beam position monitors (BPMs) and two stripline kickers located in the ATF2 extraction line to stabilise the position and angle of the beam; the correction is then measured downstream at the ATF2 beam waist by a cavity BPM. The feedforward system uses the two upstream stripline BPMs to measure the position of the beam and calculate a correction signal which is then implemented locally by a stripline kicker located near the beam waist; the correction is then measured at the beam waist by a cavity BPM. The IP feedback system uses the position measured at the ATF2 beam waist by a cavity BPM and implements a correction based on this position using the local stripline kicker; the correction is then measured at the beam waist by a cavity BPM. Tests of the upstream feedback system have demonstrated stabilisation of the ATF2 beam waist at approximately the 300 nm level; tests of the feedforward and IP feedback systems have demonstrated stabilisation of the ATF2 beam waist at approximately the 100 nm level. Additional work undertaken to improve the processing electronics of the stripline BPMs is detailed. The cavity BPMs and their electronics are characterised and offline analysis techniques to improve the BPM resolutions set out. Results demonstrating resolutions of approximately 350 nm for the stripline BPMs and 80 nm for the cavity BPMs are presented.

<p>This thesis reports on searches for supersymmetric particles, in particular neutralinos, conducted with the DELPHI detector at the LEP accelerator at CERN. The searches were performed within the framework of the Minimal Supersymmetric Standard Model (MSSM), with<i> R</i>-parity conserved and gravity mediated supersymmetry breaking.</p><p>The neutralino search covered both <i>Χ</i>0₂<i>Χ</i>0₁ and<i> </i><i>Χ</i>0<i>jΧ</i>_i0<i>i</i> (<i>j </i>=3,4 and <i>i </i>=1,2) production channels. Data collected in 1999 and 2000 were used, in total about 451 pb^-1 at centre-of-mass energies from 192 to 208 GeV. No signal was found in any of the search channels, and the results were interpreted as model independent limits on the production cross-sections of the different topologies. For deriving these limits the data analysed here were combined with those collected at a centre-of-mass energy of 189 GeV (∾ 158 pb^-1). The obtained upper limits of the cross-section for ~<i>Χ</i>0₂<i>Χ</i>0₁ production, when <i>Χ</i>0₂→ <i>Z</i>*<i>Χ</i>0₁, vary with masses of the neutralinos involved and typically range between 0.05 pb and 0.8 pb.</p><p>The negative results from all sparticle searches were used to exclude regions in the parameter space within a constrained MSSM, with gaugino and sfermion mass unification at the GUT scale, and to set limits on the sparticle masses. The mass of the lightest neutralino is constrained to be larger than 45.5 GeV/<i>c</i>² for any <i>m</i>₀, for tan <i>β ≤ </i>40 and without sfermion mixing. An interpretation of the results was also performed within the Anomaly Mediated Supersymmetry Breaking model, and the lower mass limit of the lightest neutralino is 68 GeV/<i>c</i>². All limits are given at 95% confidence level.</p><p>In the ATLAS combined testbeam 2004, a full slice of the ATLAS detector was tested. The SPS accelerator at CERN was used to create particle beams with energies from 1 to 350 GeV. The beamline instrumentation, such as scintillators, beam chambers and Cherenkov detectors, and extra detectors, are described in this thesis. The data from the testbeam were used to investigate the performance of the hadronic calorimeter for pions at various pseudorapidities and energies. The energy resolutions and linearities obtained were found to be comparable with results from earlier hadronic standalone testbeams. The obtained resolutions were about σ/<i>E</i> = 52 % / sqrt <i>E </i>[<i>GeV</i>] ⊕ 5 %.</p>

During the last decade, large and costly instruments are being replaced by system based on microfluidic devices. Microfluidic devices hold the promise of combining a small analytical laboratory onto a chip-sized substrate to identify, immobilize, separate, and purify cells, bio-molecules, toxins, and other chemical and biological materials. Compared to conventional instruments, microfluidic devices would perform these tasks faster with higher sensitivity and efficiency, and greater affordability. Dielectrophoresis is one of the enabling technologies for these devices. It exploits the differences in particle dielectric properties to allow manipulation and characterization of particles suspended in a fluidic medium. Particles can be trapped or moved between regions of high or low electric fields due to the polarization effects in non-uniform electric fields. By varying the applied electric field frequency, the magnitude and direction of the dielectrophoretic force on the particle can be controlled. Dielectrophoresis has been successfully demonstrated in the separation, transportation, trapping, and sorting of various biological particles. / Singapore-MIT Alliance (SMA)

This thesis reports on searches for supersymmetric particles, in particular neutralinos, conducted with the DELPHI detector at the LEP accelerator at CERN. The searches were performed within the framework of the Minimal Supersymmetric Standard Model (MSSM), with R-parity conserved and gravity mediated supersymmetry breaking. The neutralino search covered both Χ02Χ01 and Χ0jΧi0i (j =3,4 and i =1,2) production channels. Data collected in 1999 and 2000 were used, in total about 451 pb-1 at centre-of-mass energies from 192 to 208 GeV. No signal was found in any of the search channels, and the results were interpreted as model independent limits on the production cross-sections of the different topologies. For deriving these limits the data analysed here were combined with those collected at a centre-of-mass energy of 189 GeV (∾ 158 pb-1). The obtained upper limits of the cross-section for ~Χ02Χ01 production, when Χ02→ Z*Χ01, vary with masses of the neutralinos involved and typically range between 0.05 pb and 0.8 pb. The negative results from all sparticle searches were used to exclude regions in the parameter space within a constrained MSSM, with gaugino and sfermion mass unification at the GUT scale, and to set limits on the sparticle masses. The mass of the lightest neutralino is constrained to be larger than 45.5 GeV/c2 for any m0, for tan β ≤ 40 and without sfermion mixing. An interpretation of the results was also performed within the Anomaly Mediated Supersymmetry Breaking model, and the lower mass limit of the lightest neutralino is 68 GeV/c2. All limits are given at 95% confidence level. In the ATLAS combined testbeam 2004, a full slice of the ATLAS detector was tested. The SPS accelerator at CERN was used to create particle beams with energies from 1 to 350 GeV. The beamline instrumentation, such as scintillators, beam chambers and Cherenkov detectors, and extra detectors, are described in this thesis. The data from the testbeam were used to investigate the performance of the hadronic calorimeter for pions at various pseudorapidities and energies. The energy resolutions and linearities obtained were found to be comparable with results from earlier hadronic standalone testbeams. The obtained resolutions were about σ/E = 52 % / sqrt E [GeV] ⊕ 5 %.

This thesis investigates the properties of coherent Smith-Purcell radiation (cSPr) at femtosecond-scale in the case of electrons bunches in the ultrarelativistic regimes. Of particular interest is the use of cSPR as a diagnostic tool to determine the longitudinal time profiles of such bunches, the study of azimuthal distribution of the radiated energy, and a contribution to the understanding of polarization properties. The study consists in a first theoretical part carried mostly in the context of the surface-current theory, supported with insights from particle-in-cell simulations. Then, as a step toward a better determination of time profile, the question of phase reconstruction is addressed through the design of a new algorithm proposed in this thesis and tested in known challenging cases. Experimental results are then presented, spanning shifts having taken place at the FACET facility at SLAC, Stanford, between 2013 and 2015.

<p> The binding energy B of a A-particle in infinite nuclear matter has been estimated to be about 30 MeV by extrapolating the observed binding energies of hypernuclei. On the other hand, theoretical estimates so far done by various methods are generally much larger than 30 MeV. Various reasons for this descrepancy have been considered. We estimate the effect of the A-E conversion as one of the effects removing that descrepancy. In order to take account of the A-E conversion explicitly, it is convenient to use the so-called two-channel formalism. We calculate the binding energy B in the two-channel formalism (TCF) as well as in the more conventional one-channel formalism (OCF). It is found that B in the TCF can be substantially smaller than in the OCF. The difference of the values of B in the two formalisms is interpreted as due to the Pauli principle which suppresses the A-E conversion in nuclear matter. The relation between this effect in the TCF and three-bodyANN forces in the OCF is clarified. </p> / Thesis / Master of Science (MSc)

No description available.