A5017154366- Particle Accelerators and Free-Electron Lasers
- Particle accelerators and beam dynamics
- Photocathodes and Microchannel Plates
- Gyrotron and Vacuum Electronics Research
- Electron and X-Ray Spectroscopy Techniques
- Particle Detector Development and Performance
- Superconducting Materials and Applications
- Magnetic confinement fusion research
- Laser Design and Applications
- Radiation Therapy and Dosimetry
- Laser-Plasma Interactions and Diagnostics
- Advanced X-ray Imaging Techniques
- Plasma Diagnostics and Applications
- Atomic and Subatomic Physics Research
- Nuclear Physics and Applications
- Dark Matter and Cosmic Phenomena
- Quantum Chromodynamics and Particle Interactions
- Radiation Detection and Scintillator Technologies
- Laser-Matter Interactions and Applications
- Advanced Radiotherapy Techniques
- Embedded Systems and FPGA Applications
- Biosensors and Analytical Detection
- CCD and CMOS Imaging Sensors
- X-ray Spectroscopy and Fluorescence Analysis
- Nuclear physics research studies
Daresbury Laboratory
2010-2024
Sci-Tech Daresbury
2011-2024
Cockcroft Institute
2013-2023
University of Liverpool
2020-2022
Institute of Semiconductor Physics
2009-2022
Novosibirsk State University
2009-2022
Science and Technology Facilities Council
2019
Institute for Atomic and Molecular Physics
2000-2004
National Institute for Subatomic Physics
1998-2002
Budker Institute of Nuclear Physics
1993-2002
We report on the first measurement of spin-correlation parameters in quasifree electron scattering from vector-polarized deuterium. Polarized electrons were injected into an storage ring at a beam energy 720~MeV. A Siberian snake was employed to preserve longitudinal polarization interaction point. Vector-polarized deuterium produced by atomic source and open-ended cylindrical cell, internal ring. The spin correlation parameter A^V_{ed} measured for reaction \pol{2H}(\pol{e},e'n)p...
The influence of O2, CO2, CO, N2, H2 and CH4 on the stability quantum efficiency (QE) a negative electron affinity gallium arsenide (GaAs) photocathode activated with caesium (Cs) oxygen (O) has been demonstrated for first time under an extremely high vacuum condition, base pressure 1.5 × 10−11 mbar, where background gas is minimized. It was found that exposure GaAs to does not affect QE, whereas CO2 CO leads substantial reduction in QE. also QE photocathodes which have degraded O2 can be...
New acceleration technology is mandatory for the future elucidation of fundamental particles and their interactions. A promising approach to exploit properties plasmas. Past research has focused on creating large-amplitude plasma waves by injecting an intense laser pulse or electron bunch into plasma. However, maximum energy gain electrons accelerated in a single stage limited driver. Proton bunches are most drivers wakefields accelerate TeV scale stage. An experimental program at CERN—the...
A conceptual design is presented of a novel energy-recovering linac (ERL) facility for the development and application energy recovery technique to linear electron accelerators in multi-turn, large current regime. The main characteristics powerful experiment (PERLE) are derived from Large Hadron Collider, an beam upgrade under study LHC, which it would be key demonstrator. PERLE thus projected as investigate efficient, high (HC) (>10 mA) ERL operation with three re-circulation passages...
In this paper we report the first time demonstration under extremely high vacuum (XHV) conditions of influence O2, CO2, CO, N2, H2 and CH4 on quantum efficiency (QE) negative electron affinity (NEA) gallium arsenide (GaAs) photocathodes activated with Cs NF3. The were exposed to a small quantity (<0.25 Langmuirs) each gas species test in chamber typical base pressure mbar, thereby minimising residual photocathode response. It was found that exposure does not affect QE photocathodes, whereas...
This report describes the conceptual design of a proposed free electron laser test facility called CLARA that will be major upgrade to existing VELA accelerator at Daresbury Laboratory in UK. able number new schemes have been but require proof principle experiment confirm they perform as predicted. The primary focus on ultra short photon pulse generation which take lasers into whole regime, enabling area science emerge.
We describe a novel technique, based on image compression and machine learning, for transverse phase space tomography in two degrees of freedom an accelerator beamline. The technique has been used the CLARA test facility at Daresbury Laboratory: results from learning method are compared with those conventional algorithm (algebraic reconstruction) applied to same data. use allows reconstruction 4D distribution beam be carried out much more rapidly than using algorithms also enables reduce...
The compact linear accelerator for research and applications (CLARA) is an ultrabright electron beam test facility being developed at STFC Daresbury Laboratory. ultimate aim of CLARA to advanced free laser (FEL) schemes that can later be implemented on existing future short-wavelength FELs. In addition, a unique provide high-quality novel concepts ideas in wide range disciplines function as technology demonstrator United Kingdom x-ray FEL facility. built three phases; the first phase, or...
The (Cs,O)-activation procedure for p-GaAs(Cs,O)-photocathodes was studied with the aim of demarcating domains validity two practical models layer: dipole layer (DL) model and heterojunction (HJ) model. To do this, photocathode activated far beyond normal maximum quantum efficiency, several parameters were measured periodically during this process. In doing so, data obtained enabled us to determine DL- HJ-models, define more precisely characteristic within both these thus reveal...
A Free‐Electron Laser (FEL) places many exacting demands on a Negative Electron Affinity (NEA) photocathode, such as the need for an ultra‐fast response time, low energy spread emitted electrons, high quantum efficiency (Q.E.) and average photocurrent. However, these key requirements are conflicting, cannot be fulfilled by conventional photocathode design. For example, to achieve ∼10 ps active layer should thinned ∼100–150 nm, but this thickness is insufficient provide near‐complete...
The transverse phase space of a beam in an accelerator can be characterized using well-established methods based on observation changes the profile between screens at different locations along beamline, or single screen for strengths upstream quadrupoles. Studies CLARA FE (the Compact Linear Accelerator Research and Applications Front End, Daresbury Laboratory, UK) show that where has complicated (nonelliptical) distribution space, conventional analysis techniques aimed characterizing terms...
Powerful ERL for experiments (PERLE) is a novel energy recovery linac (ERL) test facility [1], designed to validate choices 50 GeV foreseen in the design of Large Hadron Electron Collider and Future Circular host dedicated nuclear particle physics experiments. Its main goal demonstrate high current, continuous wave, multipass operation with superconducting cavities at 802 MHz. With very beam power (10 MW), PERLE offers an opportunity controllable study every dynamic effect interest next...
We present measurements of the transverse and longitudinal energy spread photoelectrons emitted from a GaAsP photocathode as function its degradation state. The cathode was initially activated to state negative electron affinity in our preparation facility, achieving quantum efficiency 3% at wavelength 532 nm. It then transferred under XHV conditions spectrometer, where were made while progressively degraded through controlled exposure oxygen. Data have been collected illumination nm,...
The spin-momentum correlation parameter A(V)(ed) was measured for the 2H-->(e-->,e'p)n reaction missing momenta up to 350 MeV/c at Q2 = 0.21 (GeV/c)(2) quasielastic scattering of polarized electrons from vector-polarized deuterium. data give detailed information about deuteron spin structure and are in good agreement with results microscopic calculations based on realistic nucleon-nucleon potentials including various spin-dependent mechanism effects. experiment reveals a most direct manner...
MEIS and XPS studies have been conducted for a range of oxygen plasma treated copper samples (and one with Ar plasma), as part study the preparation photocathode surfaces. This procedure was seen to remove hydrocarbon contamination, but left an oxide film whose thickness depended on treatment conditions used. The increase longer time higher RF power levels behaviour characteristic diffusion limited process. Annealing led removal layer by into bulk samples. indicates that where is...
We propose a Plasma Accelerator Research Station (PARS) based at proposed FEL test facility CLARA (Compact Linear for and Applications) Daresbury Laboratory. The idea is to use the relativistic electron beam from CLARA, investigate some key issues in transport driven plasma wakefield acceleration, e.g. high gradient excitation by bunch, two bunch experiment energy doubling, transformer ratio, long self-modulation other advanced dynamics issues. This paper presents feasibility studies of meet...
We report on measurements of the cross section and provide first data spin correlation parameters ${A}_{{\mathrm{TT}}^{\ensuremath{'}}}$ ${A}_{{\mathrm{TL}}^{\ensuremath{'}}}$ in inclusive scattering longitudinally polarized electrons from nuclear-polarized hydrogen. Polarized were injected into an electron storage ring operated at a beam energy 720 MeV. hydrogen was produced by atomic source open-ended cylindrical cell, located ring. The four-momentum transfer squared ranged...
Abstract We present a study on the evolution of both transverse and longitudinal energy distributions due to oxygen–induced quantum efficiency degradation in electrons emitted from reflection–mode p-GaAs(Cs,O)-photocathode over an effective electron affinity range χ * ∼ −0.1 eV +0.3 under illumination wavelengths λ = 808, 635 532 nm. For nm, we found that mean as photocathode increased has non–monotonic character. Our proposed fitting model links measured response changes relative number...