A5081314183- Photocathodes and Microchannel Plates
- Electron and X-Ray Spectroscopy Techniques
- Particle Accelerators and Free-Electron Lasers
- Particle Detector Development and Performance
- Advanced X-ray Imaging Techniques
- Various Chemistry Research Topics
- Radiation Therapy and Dosimetry
- Organic Chemistry Cycloaddition Reactions
- Laser-Plasma Interactions and Diagnostics
- Laser Design and Applications
- Gyrotron and Vacuum Electronics Research
- Particle accelerators and beam dynamics
- Dark Matter and Cosmic Phenomena
- Radical Photochemical Reactions
- Molecular Junctions and Nanostructures
- Photochemistry and Electron Transfer Studies
- Chemical Reaction Mechanisms
- Plasma Diagnostics and Applications
- Chemical Reactions and Mechanisms
- Radiation Detection and Scintillator Technologies
- Superconducting Materials and Applications
- Advanced Chemical Physics Studies
- Advanced X-ray and CT Imaging
- Neuroscience and Music Perception
- Surface Chemistry and Catalysis
Daresbury Laboratory
2009-2024
Cockcroft Institute
2011-2024
Sci-Tech Daresbury
2011-2024
Science and Technology Facilities Council
2008-2023
Institute of Semiconductor Physics
2009-2022
Novosibirsk State University
2009-2022
University of Liverpool
2005-2022
Seton Hill University
2007-2011
London Metropolitan University
2011
University of Manchester
2009
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...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMechanisms of Photochemical Reactions in Solution. XXX.1 Photosensitized Isomerization AzobenzeneLee B. Jones and George S. HammondCite this: J. Am. Chem. Soc. 1965, 87, 18, 4219–4220Publication Date (Print):September 1, 1965Publication History Published online1 May 2002Published inissue 1 September 1965https://pubs.acs.org/doi/10.1021/ja01096a059https://doi.org/10.1021/ja01096a059research-articleACS PublicationsRequest reuse permissionsArticle...
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...
With their high quantum efficiency (QE) and excellent photoemissive properties, cesium telluride (Cs-Te) photocathodes are the current workhorse in average electron accelerators around globe. Their ability to generate brightness charge beams has opened doorway numerous applications, including fundamental particle physics research, radiation therapy, high-energy experiments, repetition rate free-electron lasers (FELs). long-term performance is critical. In this work, we analyze systematic...
Abstract Inverse Compton scattering is a promising method to implement high brightness, ultra-short, energy tunable X-ray source at accelerator facilities. We have developed an inverse backscattering driven by the multi-10 TW laser installed Daresbury. Hard X-rays, with spectral peaks ranging from 15 30 keV, depending on geometry, will be generated through interaction of pulses electron bunches delivered recovery linac machine, initially known as prototype and subsequently renamed...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMechanisms of Photochemical Reactions in Solution. XL.1 Steric Hindrance to Energy TransferWilliam G. Herkstroeter, Lee B. Jones, and George S. HammondCite this: J. Am. Chem. Soc. 1966, 88, 21, 4777–4780Publication Date (Print):November 1, 1966Publication History Published online1 May 2002Published inissue 1 November 1966https://pubs.acs.org/doi/10.1021/ja00973a002https://doi.org/10.1021/ja00973a002research-articleACS PublicationsRequest reuse...
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...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotolyses of trienes. II. Selective photoreactions 2,7,7-trimethylcycloheptatrieneLee B. Jones and Vera K. JonesCite this: J. Am. Chem. Soc. 1968, 90, 6, 1540–1543Publication Date (Print):March 1, 1968Publication History Published online1 May 2002Published inissue 1 March 1968https://pubs.acs.org/doi/10.1021/ja01008a024https://doi.org/10.1021/ja01008a024research-articleACS PublicationsRequest reuse permissionsArticle...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotolyses of Trienes. Selective Photoreactions 3,7,7-TrimethylcycloheptatrieneLee B. Jones and Vera K. JonesCite this: J. Am. Chem. Soc. 1967, 89, 8, 1880–1883Publication Date (Print):April 1, 1967Publication History Published online1 May 2002Published inissue 1 April 1967https://pubs.acs.org/doi/10.1021/ja00984a021https://doi.org/10.1021/ja00984a021research-articleACS PublicationsRequest reuse permissionsArticle Views49Altmetric-Citations20LEARN...
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...
Abstract The generation of high-brightness electron beams is a crucial area particle accelerator research and development. Photocathodes which offer high levels quantum efficiency when illuminated at visible wavelengths are attractive as the drive laser technology greatly simplified. higher power available longer create headroom allowing use manipulation techniques to optimise longitudinal transverse beam profiles, so minimise emittance. Bi–alkali photocathodes ∼ 10 % under illumination 532...
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 adsorption of oxygen on the chiral Pt{531} surface was studied by high-resolution X-ray photoelectron spectroscopy (HRXPS) and low energy electron diffraction (LEED). After is annealed in (3 x 10(-7) mbar), three O 1s peaks are observed XPS. One peak, at 529.5 eV, assigned to chemisorbed oxygen; it disappears after annealing vacuo temperatures above 900 K. other two 530.8 532.3 eV stable up least 1250 They associated with oxide clusters surface. These readily react coadsorbed carbon...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectronic effects in solvolysis reactions. III. Solvolysis of allyl-substituted cumyl derivativesLee B. Jones and James P. FosterCite this: J. Org. Chem. 1970, 35, 6, 1777–1781Publication Date (Print):June 1, 1970Publication History Published online1 May 2002Published inissue 1 June 1970https://pubs.acs.org/doi/10.1021/jo00831a013https://doi.org/10.1021/jo00831a013research-articleACS PublicationsRequest reuse permissionsArticle...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotolyses of trienes. III. Photoreactions 2,3,7,7-tetramethyl-cycloheptatrieneLee B. Jones and Vera K. JonesCite this: J. Org. Chem. 1969, 34, 5, 1298–1302Publication Date (Print):May 1, 1969Publication History Published online1 May 2002Published inissue 1 1969https://pubs.acs.org/doi/10.1021/jo01257a020https://doi.org/10.1021/jo01257a020research-articleACS PublicationsRequest reuse permissionsArticle Views35Altmetric-Citations9LEARN ABOUT THESE...
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...
Polarized X-ray pulses at <i>0.6 Å</i> have been generated <i>via</i> head-on collision of a laser pulse from the high-field facility Daresbury with <i>30 MeV</i> electron bunch in ALICE energy recovery linear accelerator. The angular distribution backscattered X rays was obtained single-shot using scintillation screen. temporal profile ray yield as function time delay between and measured agreed well that expected point dependence laser-electron beam longitudinal overlap.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe nucleophilicity of chloride ion toward carbonyl carbonLee B. Jones and James P. FosterCite this: J. Org. Chem. 1967, 32, 9, 2900–2901Publication Date (Print):September 1, 1967Publication History Published online1 May 2002Published inissue 1 September 1967https://pubs.acs.org/doi/10.1021/jo01284a059https://doi.org/10.1021/jo01284a059research-articleACS PublicationsRequest reuse permissionsArticle Views86Altmetric-Citations4LEARN ABOUT THESE...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotolysis of some carbohydrate dithiobis(thioformates)Edward I. Stout, William M. Doane, Charles R. Russell, and Lee B. JonesCite this: J. Org. Chem. 1975, 40, 9, 1331–1336Publication Date (Print):May 1, 1975Publication History Published online1 May 2002Published inissue 1 1975https://pubs.acs.org/doi/10.1021/jo00897a033https://doi.org/10.1021/jo00897a033research-articleACS PublicationsRequest reuse permissionsArticle...