A5038548694- Particle accelerators and beam dynamics
- Particle Accelerators and Free-Electron Lasers
- Superconducting Materials and Applications
- Plasma Diagnostics and Applications
- Physics of Superconductivity and Magnetism
- Particle physics theoretical and experimental studies
- Particle Detector Development and Performance
- Nuclear Physics and Applications
- Metal and Thin Film Mechanics
- Electron and X-Ray Spectroscopy Techniques
- Gas Dynamics and Kinetic Theory
- High-Energy Particle Collisions Research
- Photocathodes and Microchannel Plates
- Fusion materials and technologies
- Diamond and Carbon-based Materials Research
- Advancements in Photolithography Techniques
- Semiconductor materials and devices
- Gyrotron and Vacuum Electronics Research
- X-ray Spectroscopy and Fluorescence Analysis
- Laser-induced spectroscopy and plasma
- Atomic and Molecular Physics
- Muon and positron interactions and applications
- Spacecraft and Cryogenic Technologies
- Quantum, superfluid, helium dynamics
- Quantum Chromodynamics and Particle Interactions
Daresbury Laboratory
2014-2024
Cockcroft Institute
2007-2023
Moscow Power Engineering Institute
2008-2021
Science and Technology Facilities Council
2007-2019
European Organization for Nuclear Research
2017
University of Dundee
2014
Universität Hamburg
2012
University of Oxford
2008
University of Liverpool
2007
Sci-Tech Daresbury
2007
Secondary electron yield (SEY or δ) limits the performance of a number devices. Particularly, in high-energy charged particle accelerators, beam-induced multipacting is one main sources cloud (e-cloud) build up on beam path; radio frequency wave guides, their lifetime and causes power loss; detectors, secondary electrons define signal background reduce sensitivity. The best solution would be material with low SEY coating for many applications δ < 1 sufficient. We report an alternative...
Recent advances in vacuum sciences and applications are reviewed. Novel optical interferometer cavity devices enable pressure measurements with ppm accuracy. The innovative dynamic standard allows for temporal resolution of 2 ms. Vacuum issues the construction huge ultra-high worldwide surface science thin films include new phenomena observed electron transport near solid surfaces as well novel results on properties carbon nanomaterials. Precise techniques thin-film characterization have...
Electron cloud mitigation is an essential requirement for high-intensity proton circular accelerators. Among other solutions, laser engineered surface structures (LESS) present the advantages of having potentially a very low secondary electron yield (SEY) and allowing simple scalability mass production. Two copper liners with LESS have been manufactured successfully tested by monitoring current in dipole magnet SPS accelerator at CERN during 2016 run. In this paper we report on these results...
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...
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...
Knowing the residual gas spectrum is essential for many applications and research in ultrahigh vacuum (UHV). Residual analyzers (RGAs) are used both qualitative quantitative analyses, where quadrupole mass now most popular. It was found that RGAs supplied by different manufacturers not necessarily well calibrated analysis. A procedure applied situ RGA “calibration” against a UHV total pressure gauge described this article. special attention should be paid to H2 calibration, as usually much...
During heavy-ion operation in several particle accelerators worldwide, dynamic pressure rises of orders magnitude were triggered by lost beam ions that bombarded the vacuum chamber walls. This ion-induced molecular desorption, observed at CERN, GSI, and BNL, can seriously limit ion lifetime intensity accelerator. From dedicated test stand experiments we have discovered heavy-ion-induced gas desorption scales with electronic energy loss ($d{E}_{e}/dx$) slowing down matter; but it varies only...
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...
In this study, two identical 316LN stainless steel tubular samples, which had previously been polished and vacuum-fired then used for the electron-stimulated desorption (ESD) experiments, were coated with Ti-Zr-Hf-V different morphologies: columnar dense. ESD measurement results after nonevaporable getter (NEG) activation to 150, 180, 250, 350 °C indicated that values yields are significantly (2–20 times) lower than data from our previous study similar coatings on nonvacuum-fired samples....
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...
Reduction of SEY was achieved by surface engineering through laser ablation with a operating at • = 355 nm. It shown that the can be reduced to near or below 1 on copper, aluminium and 316LN stainless steel. The treated surfaces show an increased resistance, wide variation in resistance found de-pending exact treatment details. However, copper similar produced.
The results of 4.2-K photodesorption experiments in two quasiclosed geometries are reported, (1) a simple tube and (2) with coaxial perforated liner. These were designed to measure separately the desorption coefficients tightly bound physisorbed molecules. important for beam vacuum next generation superconducting proton colliders that have been contemplated—the 20-TeV Superconducting Super Collider United States 7.3-TeV Large Hadron at CERN.