A5101985902- Particle accelerators and beam dynamics
- Metal and Thin Film Mechanics
- Particle Accelerators and Free-Electron Lasers
- Ion-surface interactions and analysis
- Superconducting Materials and Applications
- Plasma Diagnostics and Applications
- Semiconductor materials and devices
- Diamond and Carbon-based Materials Research
- Physics of Superconductivity and Magnetism
- Gyrotron and Vacuum Electronics Research
- Fusion materials and technologies
- Electron and X-Ray Spectroscopy Techniques
- Integrated Circuits and Semiconductor Failure Analysis
- Photocathodes and Microchannel Plates
- Advanced Materials Characterization Techniques
- Nuclear Physics and Applications
- Advancements in Photolithography Techniques
- Laser-induced spectroscopy and plasma
- Magnetic confinement fusion research
- Silicon and Solar Cell Technologies
- Laser Material Processing Techniques
- Atomic and Molecular Physics
- Scientific Measurement and Uncertainty Evaluation
- Copper Interconnects and Reliability
- Thin-Film Transistor Technologies
Cockcroft Institute
2016-2024
Daresbury Laboratory
2013-2024
Sci-Tech Daresbury
2024
University of Shahrood
2021
Manchester Metropolitan University
2001-2012
University of Salford
1991-1998
The performance of a UHV vessel can be improved with new CERN technology nonevaporable getter (NEG) coating, which is already widely used for accelerator vacuum chambers. Better understanding the processes involved in NEG film deposition, activation, and poisoning should allow optimization engineering properties, are necessary particular application. Ti–Zr–V films were created by magnetron sputtering from single target, morphology dependence on deposition pressure, conditions, substrate...
Electron photoinjectors provide high-brightness electron beams to numerous research applications in physics, chemistry, material, and life sciences. Semiconductor photocathodes are widely used here, as they enable the production of low-emittance with variable charge at high repetition rates. One key figures merit is minimum achievable bunch length. In semiconductor cathodes, this dominated by scattering effects varying penetration depths extracting photons, which leads a characteristic...
The paper presents the first study of abrasion resistance and degradation processes magnetron-sputtered Nb3Sn coatings on electropolished (EP) or chemical polished (CP) copper substrates. coating-substrate system is interest for application in radio frequency superconducting cavities as an improvement bulk niobium cavities. microstructural properties substrates coating were examined by scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS), backscatter diffraction,...
A comparison of the performance nonevaporable getter (NEG) films deposited using two different types targets has been made to find one that best pumping properties. For first time, NEG coating was a preformed Ti-Zr-V alloy target. The film characterization and properties have studied in with commonly used three-wire twisted It demonstrated target produces uniform composition both laterally depth. found be same as Film topography microstructure 5 nm grain sizes were for targets. main result...
An experimental setup for studying the pumping and capacity properties of nonevaporable getter (NEG)-coated films has been designed built in ASTeC Vacuum Science Laboratory at Daresbury Laboratory. The measurement system is based on dynamic expansion method with a gas injection that capable injecting residual gases present typical UHV system, such as H2, CO, CO2, CH4. test particle Monte Carlo model was used accurate evaluation NEG film sticking probability from pressure reading during...
Abstract The time evolution of the positive ion energy distribution functions (IEDF’s) at substrate position in an asymmetric bipolar high-power impulse magnetron sputtering (HiPIMS) system was determined using a gridded analyser. This done for range operating conditions, namely voltage U rev and ‘on-time’ negative pulse duration τ neg . discharge equipped with Nb target. Based on knowledge IEDF’s, bombarding flux density Γ i Q to grounded surface were calculated. Time-resolved IEDF...
Thin silicon nitride (Si(1_x)N(x)) films were synthesized without substrate heating by means of reactive argon-ion sputtering either or a target in the 1000-1500-eV energy range at nitrogen partial pressure 1.3 × 10(-2) Pa and with simultaneous ion-assisted bombardment 300-500-eV low range. The extinction coefficient refractive index directly dependent on N(+) ion-to-atom arrival ratio, assisted ion energy, film growth rate, indicated correlation stoichiometry disorder. Si(3)N(4) obtained...
An installation for investigation of the electron stimulated desorption (ESD) from both pumping and nonpumping tubular samples was designed built. This allows studying ESD sample sticking probability as a function dose up to about 1023 e−/m2, energy in range 10 eV–6.5 keV, sampling temperature 0–80 °C. Two were investigated: bare Ti–Zr–V coated stainless steels. The yields measured accumulated dose, energy, different NEG coating activation temperatures. effect CO saturated demonstrated first...
The ASTeC Vacuum Science Group has an ongoing study for the improvement of nonevaporable getter (NEG) coatings currently used in many accelerators around world. main advantages using NEG are evenly distributed pumping speed, low thermal outgassing rates, and photon-stimulated gas desorption electron-stimulated (ESD). Previously, it was shown that dense coating provides lower ESD compared to a columnar film, but its properties reduced. This paper describes results dual layer where deposited...
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...
The performance of Nb superconducting radio-frequency (SRF) cavities in particle accelerators is often limited by breakdown events below the intrinsic limiting surface fields Nb. Though excellent rf properties have been achieved, a detailed understanding causal links between treatment, defects, and ultimate lacking. This study uses magnetic writer probe from conventional hard-disk drive as near-field microwave microscope, to localized response SRF-grade samples. reveals nonlinear due...
A study of surface contact and separation ceramic-on-ceramic joints was undertaken in 25 per cent bovine serum using a hip simulator. An electrical resistivity technique used to detect the extent throughout complete walking cycle. The femoral acetabular components were coated thin conducting film titanium nitride allow application non-conducting ceramic. Surface detected each simulated Fluctuations applied voltage across joint observed which could not be attributed elastohydrodynamic or...
Abstract The maximum accelerating gradient of superconducting radio frequency cavities are currently reaching their theoretical limits, due to the magnetic field entering superconductor in form vortices. To overcome these thin film coated materials required, however need be tested optimise properties. A system has been designed, built, and commissioned at Daresbury Laboratory that applies a local DC parallel surface, from one side sample, similar cavity operation. flux density (up 600 mT) is...
To develop methods for the formation of metal-insulator-semiconductor (MIS) devices at low temperature, thin SiO2, SiOXNY, and SiNX films were reactively sputtered onto nonheated silicon substrates using different sputtering ion assist parameters. SiO2 was prepared by bombarding Si with Ar+ ions in Ar/O2 ambient whereas SiOXNY Si3N4 N2+ N2/O2 Ar/N2 ambients, respectively. In addition, 300 eV assistance used during preparation to enhance film nitriding. The 100–300 also investigate electrical...