Books

The generation of ultrashort electron bunches is an active area of research in accelerator physics. A key application of such bunches is the injection into novel accelerators with high-frequency accelerating fields, such as laser-wakefield plasma accelerators or dielectric laser accelerators. [...]

Report on the Mini WorkshopPrecision EW and QCD Calculations for the FCC Studies: Methods and Tools, 12–13 January 2018, CERN, Geneva

This thesis is about simulations, proof-of-principle experimental setups and first test experiments for new ultra-compact particle accelerators based on dielectric structures. Due to the high damage threshold of nano- and micrometer-scale dielectrics in the optical regime, accelerating fields on the order of GV/m can be achieved. [...]

In this work, plasma wakefield acceleration with high transformer ratios, i.e. highratios between acceleration of witness particles to deceleration of driver particles, is investigated experimentally.Particle-beam-driven plasma wakefield acceleration (PWFA) is one of the primecandidates for future compact accelerator technologies. [...]

The study of condensed matter dynamics on ultrafast timescales is one of the key topics in modern material science research. Hard X-ray free-electron laser sources with extreme peak brightness and ultra short pulses provide excellent conditions for studying ultrafast dynamics in the time domain by employing such techniques as X-ray pump-probe spectroscopy or X-ray photon correlation spectroscopy. [...]

The coherent synthesis of pulses from Optical Parametric Amplifiers (OPAs) offers the possibility to realize field-controlled electromagnetic waveforms with sub-cycle durations, widely scalable in energy and spectral bandwidth.Here we demonstrate a fully functional prototype of a mJ-level two channel parametric waveform synthesizer, which is ready to be upgraded to three channels. The synthesized field, whose bandwidth covers more than 2 octaves, from ~500 nm to ~2200 nm, can be compressed to a non-sinusoidal sub-cycle waveform close to the transform-limit.The long term stable operation of such a complex laser source is achieved, for the first time, by means of a sophisticated optical and mechanical design of the whole OPA system, along with targeted improvements made to the commercial pump laser.A new seeding scheme based on multiple supercontinua, further scalable to the mid-IR, leads to excellent phase stability among the different OPA channels and to a simplified dispersion management scheme.A detailed study, both theoretical and experimental, of the couplings among different pulse parameters during the parametric amplification, unveiled novel details of the Carrier-Envelope-Phase (CEP) stabilization process via OPA, and guided the design of the CEP-controlled seeding front-end.A simplified two-dimensional spectral shearing interferometry setup, where the ancillary pulses are obtained by spectral filtering the pump pulses, has been developed to easily characterize the spectral phase of the ultrabroadband pulses from each channel, overcoming the limitation of second-harmonic-based methods.Furthermore, ad-hoc nonlinear optical techniques have been deployed to observe the most relevant synthesis parameters such as the CEP of the seeding pulses and the relative phase among the different channels outputs. [...]

This thesis is focused on the search for pair production of the supersymmetric $\tau$ lepton partners within the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC). The search is performed using the data collected at a center-of-mass-energy $\sqrt{s} = 13$ TeV with the CMS detector in the years 2016-2017.One of the most popular extensions of the Standard Model (SM) is supersymmetry (SUSY). [...]

The International Linear Collider (ILC) is a planned electron-positron collider with a first stage at a center-of-mass energy of 250 GeV. The electron beam will be polarized to 80% and the positron beam to 30%. [...]

Plasma wakefields are a promising approach for the acceleration of electrons with ultrahigh (10 to 100 GV/m) electric fields. Nowadays, high-intensity laser pulses are routinely utilized to excite these large-amplitude plasma waves. [...]