Benjamin Woolley
A5087223292- Particle Accelerators and Free-Electron Lasers
- Particle accelerators and beam dynamics
- Laser-Plasma Interactions and Diagnostics
- Gyrotron and Vacuum Electronics Research
- Magnetic confinement fusion research
- Superconducting Materials and Applications
- Particle Detector Development and Performance
- Radio Frequency Integrated Circuit Design
- Particle physics theoretical and experimental studies
- Radiation Therapy and Dosimetry
- Philosophy and History of Science
- Pulsed Power Technology Applications
- Solar and Space Plasma Dynamics
- Atomic and Molecular Physics
- Microwave Engineering and Waveguides
- Ionosphere and magnetosphere dynamics
- Linguistic Education and Pedagogy
- Plasma and Flow Control in Aerodynamics
- Photonic and Optical Devices
- High-Velocity Impact and Material Behavior
- Advanced biosensing and bioanalysis techniques
- History and Theory of Mathematics
- Laser-Matter Interactions and Applications
- Media and Digital Communication
- Linguistic research and analysis
Imperial College London
2024-2025
European Organization for Nuclear Research
2017-2024
Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati
2024
Campbell Collaboration
2020-2022
Lancaster University
2014-2020
Instituto de Física Corpuscular
2020
Google (United States)
2019
High energy particle accelerators have been crucial in providing a deeper understanding of fundamental particles and the forces that govern their interactions. In order to increase or reduce size accelerator, new acceleration schemes need be developed. Plasma wakefield acceleration, which electrons plasma are excited, leading strong electric fields, is one such promising novel technique. Pioneering experiments shown an intense laser pulse electron bunch traversing plasma, drives fields 10s...
We show in experiments that a long, underdense, relativistic proton bunch propagating plasma undergoes the oblique instability, which we observe as filamentation. determine threshold value for ratio between transverse size and skin depth instability to occur. At threshold, outcome of experiment alternates filamentation self-modulation (evidenced by longitudinal modulation into microbunches). Time-resolved images density distribution reveal grows an observable level late along bunch,...
Plasma wakefield acceleration is a promising technology to reduce the size of particle accelerators. The use high energy protons drive wakefields in plasma has been demonstrated during Run 1 AWAKE programme at CERN. Protons 400 GeV drove that accelerated electrons 2 under 10 m plasma. collaboration now embarking on with main aims demonstrate stable accelerating gradients 0.5–1 GV/m, preserve emittance electron bunches and develop sources scalable 100s metres beyond. By end 2, scheme should...
Experimental results show that hosing of a long particle bunch in plasma can be induced by wakefields driven short, misaligned preceding bunch. Hosing develops the plane misalignment, self-modulation perpendicular plane, at frequencies close to electron frequency, and are reproducible. Development depends on misalignment direction, its growth extent proton charge. Results have main characteristics theoretical model, relevant other plasma-based accelerators represent first characterization...
Lanthanide–tetrazine complexes were synthesised and evaluated via optical spectroscopy relaxivity. A bio-orthogonal click reaction with a cyclic-RGD-peptide was successful the resulting Gd complex demonstrated enhanced
A long, narrow, relativistic charged particle bunch propagating in plasma is subject to the self-modulation (SM) instability. We show that SM of a proton can be seeded by wakefields driven preceding electron bunch. timing reproducibility and control are at level small fraction modulation period. With this seeding method, we independently amplitude seed with charge growth rate Seeding leads larger than instability case.
We use a relativistic ionization front to provide various initial transverse wakefield amplitudes for the self-modulation of long proton bunch in plasma. show experimentally that, with sufficient amplitude [$\ensuremath{\ge}(4.1\ifmmode\pm\else\textpm\fi{}0.4)\text{ }\text{ }\mathrm{MV}/\mathrm{m}$], phase modulation along is reproducible from event event, 3%--7% (of $2\ensuremath{\pi}$) rms variations all bunch. The not lower amplitudes. observe transition between these two regimes. Phase...
CERN has constructed and is operating a klystron- based X-band test stand, called Xbox-1, dedicated to the high-gradient testing of prototype accelerating structures for CLIC other applications such as FELs. The stand now been in operation year significant progress made understanding system, improving its reliability, upgrading hardware implementing automatic algorithms conditioning structures.
The CLIC study has progressively tested prototype accelerating structures which incorporate an ever increasing number of features are needed for a final version ready to be installed in linear collider. most recent high power test made the CERN X-band stand, Xbox-1, is CERN-built includes damping but also compact input and output couplers, maximize overall length active gradient ratio structure. structure’s high-gradient performance, 105 MV/m at 250 ns pulse low breakdown rate, matches...
A novel high-gradient accelerating structure with low phase velocity, $v/c=0.38$, has been designed, manufactured and high-power tested. The was designed built using the methodology technology developed for CLIC $100\text{ }\text{ }\mathrm{MV}/\mathrm{m}$ structures, which have speed of light but adapts them to a nonrelativistic particles. parameters were optimized compact proton therapy linac project, specifically 76 MeV energy protons, type opens more generally possibility velocity linacs....
New developments relating to compact X-band, SLED-I type pulse compressors being developed at CERN for testing high gradient structures are described. Pulse of interest take rf pulses from one or more power klystrons with duration typically $>1.5\text{ }\text{ }\ensuremath{\mu}\mathrm{s}$ and deliver up 5 times the input a shorter $<250\text{ }\mathrm{ns}$. Time domain models compressor operation low level (LLRF) control have been developed. Input drive amplitude phase each is evolved...
We study experimentally the longitudinal and transverse wakefields driven by a highly relativistic proton bunch during self-modulation in plasma. show that wakefields' growth amplitude increase with increasing seed as well charge using maximum radius of distribution measured on screen downstream from externally injecting electrons measuring their final energy. Measurements agree trends predicted theory numerical simulations validate our understanding development self-modulation. Experiments...
Abstract In 2017, AWAKE demonstrated the seeded self-modulation (SSM) of a 400 GeV proton beam from Super Proton Synchrotron at CERN. The angular distribution protons deflected due to SSM is quantitative measure process, which agrees with simulations by two-dimensional (axisymmetric) particle-in-cell code LCODE about 5%. agreement achieved in population scans two selected plasma densities and scan longitudinal density gradient. reached only case wide enough simulation box (several...
In this article, we briefly summarize the experiments performed during first Run of Advanced Wakefield Experiment, AWAKE, at CERN (European Organization for Nuclear Research). The final goal AWAKE 1 (2013 - 2018) was to demonstrate that \unit[10-20]{MeV} electrons can be accelerated GeV-energies in a plasma wakefield driven by highly-relativistic self-modulated proton bunch. We describe experiment, outline measurement concept and present results. Last, our plans future.
We study experimentally the effect of linear plasma density gradients on self-modulation a 400\,GeV proton bunch. Results show that positive/negative gradient in/decreases number micro-bunches and relative charge per micro-bunch observed after 10\,m plasma. The measured modulation frequency also in/decreases. With largest positive we observe two frequencies in power spectrum. are consistent with changes wakefields' phase velocity due to adding slow during growth predicted by theory.
Self-modulation is a beam–plasma instability that useful to drive large-amplitude wakefields with bunches much longer than the plasma skin depth. We present experimental results showing that, when increasing ratio between initial transverse size of bunch and depth, occurs later along bunch, or not at all, over fixed length because amplitude decreases. show cases for which self-modulation does develop, we introduce simple model discussing conditions it would occur after any length. Changing...
The Compact Linear Collider (CLIC) beam-based acceleration baseline uses high-gradient travelling wave accelerating structures at a frequency of 12 GHz. In order to prove the performance these high peak power and short pulse width RF, two klystron-based test facilities have been put in operation last years. third X-band testing facility CERN (Xbox3) has recently commissioned tripled number slots available. Xbox3 novel way combining relatively low (6 MW) but average klystron units whose is...
This article presents the design, construction, and high-power test of two <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$X$ </tex-math></inline-formula> -band radio frequency (RF) accelerating structures built as part a collaboration between CERN Paul Scherrer Institute (PSI) for compact linear collider (CLIC) study. The are modified "tuning-free" variant an existing design were assembled using Swiss...
A normal-conducting, X-band traveling wave structure operating in the dipole mode has been systematically high-gradient tested to gain insight into maximum possible gradients these types of structure. Measured conditioning, breakdown behavior, and achieved surface fields are reported as well a postmortem analysis position scanning electron microscope high-field surfaces. The results measurements then compared from monopole-mode cavities. Scaled rate ${10}^{\ensuremath{-}6}$, cavities were...