K. Paraschou
A5020338119- Particle Detector Development and Performance
- Radiation Detection and Scintillator Technologies
- Particle Accelerators and Free-Electron Lasers
- Particle physics theoretical and experimental studies
- Superconducting Materials and Applications
- Photocathodes and Microchannel Plates
- Particle accelerators and beam dynamics
- CCD and CMOS Imaging Sensors
- Dark Matter and Cosmic Phenomena
- Distributed and Parallel Computing Systems
- Laser-Plasma Interactions and Diagnostics
- Muon and positron interactions and applications
- Atomic and Subatomic Physics Research
- Advanced Data Storage Technologies
- Radiation Effects in Electronics
- Plasma Diagnostics and Applications
- High-Energy Particle Collisions Research
- Advancements in Photolithography Techniques
- Magnetic confinement fusion research
- Advanced X-ray Imaging Techniques
- Astrophysics and Cosmic Phenomena
European Organization for Nuclear Research
2021-2024
University of Naples Federico II
2024
Aristotle University of Thessaloniki
2019-2022
Campbell Collaboration
2020
Institut de Recherche sur les Lois Fondamentales de l'Univers
2018-2019
CEA Paris-Saclay
2018-2019
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2018-2019
Université Paris-Saclay
2018-2019
Hypothetical low-mass particles, such as axions, provide a compelling explanation for the dark matter in universe. Such particles are expected to emerge abundantly from hot interior of stars. To test this prediction, CERN Axion Solar Telescope (CAST) uses 9 T refurbished Large Hadron Collider magnet directed towards Sun. In strong magnetic field, solar axions can be converted X-ray photons which recorded by detectors. 2013–2015 run, thanks low-background detectors and new telescope,...
The prospect of pileup induced backgrounds at the High Luminosity LHC (HL-LHC) has stimulated intense interest in developing technologies for charged particle detection with accurate timing high rates. required accuracy follows directly from nominal interaction distribution within a bunch crossing ($\sigma_z\sim5$ cm, $\sigma_t\sim170$ ps). A time resolution order 20-30 ps would lead to significant reduction these backgrounds. With this goal, we present new concept called PICOSEC, which is...
Laser-induced surface roughening is a technique that facilitates the reduction of secondary electron emission (SEE) from materials, which crucial for mitigating cloud (EC) formation in particle accelerators, that...
The spatial dependence of the timing performance R3809U-50 Micro-Channel-Plate PMT (MCP-PMT) by Hamamatsu was studied in high energy muon beams. Particle position information is provided a GEM tracker telescope, while measured relative to second MCP-PMT, identical construction. In inner part circular active area (radius r<5.5 mm) time resolution two MCP-PMTs combined better than 10 ps. signal amplitude decreases outer region due less light reaching photocathode, resulting worse resolution....
Xsuite is a newly developed modular simulation package combining in single flexible and modern framework the capabilities of different tools at CERN past decades, notably Sixtrack, Sixtracklib, COMBI PyHEADTAIL. The suite consists set Python modules (Xobjects, Xpart, Xtrack, Xcoll, Xfields, Xdeps) that can be flexibly combined together with other accelerator-specific general-purpose python to study complex scenarios. code allows for symplectic modeling particle dynamics, effect synchrotron...
We report on a new search for solar chameleons with the CERN Axion Solar Telescope (CAST). A GridPix detector was used to soft X-ray photons in energy range from 200 eV 10 keV converted chameleons. No signiffcant excess over expected background has been observed data taken 2014 and 2015. set an improved limit chameleon photon coupling, $\beta_\gamma < 5.7\times10^{10}$ $1<\beta_\mathrm{m}<10^6$ at 95% C.L. improving our previous results by factor two first time reaching sensitivity below...
Detectors with a time resolution of few tens picoseconds and long-term durability in high particle fluxes are necessary for an accurate vertex separation future physics experiments. The PICOSEC-Micromegas detector concept is Micro-Pattern Gaseous Detector (MPGD) based solution addressing this particular challenge. It on Micromegas coupled to Cherenkov radiator photocathode. Primary electrons from the incident particles generated photocathode fluctuations due different primary ionisation...
Abstract Detectors with a time resolution of 20-30 ps and reliable performance in high particles flux environments are necessary for an accurate vertex separation future HEP experiments. The PICOSEC-Micromegas detector concept is Micro-Pattern Gaseous Detector (MPGD) based solution addressing this particular challenge. on Micromegas coupled to Cherenkov radiator photocathode. In concept, all primary electrons initiated the photocathode jitter fluctuations reduced. Different resistive anode...
In this work, a part of the Research and Development effort PICOSEC detector is presented. The novel gas-filled detector, based on Micromegas which has been developed by RD-51 collaboration. Instead relying traditional direct ionization, takes advantage prompt timing characteristics Cherenkov radiation converting photons into electrons through use photocathode. put two type tests where experimental data are collected. One involves laser beam single photoelectron response at CEA-SACLAY, while...
Abstract The PICOSEC-Micromegas detector was developed for precise timing of the arrival charged particles with a resolution bellow 30 ps. This contribution, after brief introduction presents results concerning response to single photoelectrons, estimation photoelectron yield various photocathode types, as well its performance time test beam muons. In addition, based on detailed simulation studies and stochastic model understanding are presented. Finally, related development large scale...
Abstract Operation of the Large Hadron Collider (LHC) requires strong octupolar magnetic fields to suppress coherent beam instabilities. The amplitude detuning that is generated by these brings tune individual particles close harmful resonances, which are mostly driven themselves. In 2023, new optics were deployed in LHC at injection with optimized betatronic phase advances minimize resonances from without affecting detuning. This paper reports on design, commissioning, and lifetime...
Abstract The High Luminosity (HL-LHC) project aims to increase the integrated luminosity of CERN's Large Hadron Collider (LHC) by an order magnitude compared its initial design. This requires a large in bunch intensity and beam brightness first three LHC runs, hence poses serious collective-effects challenges, related particular electron cloud, instabilities from beam-coupling impedance, beam-beam effects. Here, we present associated constraints mitigation measures proposed achieve baseline...
The experimental requirements in near future accelerators (e.g. High Luminosity-LHC) has stimulated intense interest development of detectors with high precision timing capabilities. With this as a goal, new detection concept called PICOSEC, which is based to "two-stage" MicroMegas detector coupled Cherenkov radiator equipped photocathode been developed. Results obtained yield time resolution 24 ps for 150 GeV muons and 76 single photoelectrons. In paper we will report on the performance...
In the Large Hadron Collider, electron clouds have been observed to cause slow beam degradation in form of lifetime reduction and emittance growth. We present a method for simulation such effects with arbitrarily complex presence non-linearities lattice accelerator. The application cloud forces, as obtained from particle-in-cell dynamics, is kept symplectic by using an appropriate tricubic interpolation scheme. properties scheme are studied detail numerical artifacts that can be introduced...
This work presents the concept of PICOSEC-Micromegas detector to achieve a time resolution below 30 ps. PICOSEC consists two-stage Micromegas coupled Cherenkov radiator and equipped with photocathode. The results from single-channel prototypes as well understanding in terms detailed simulations preliminary multichannel prototype are presented.
During the operation of Large Hadron Collider in 2018, majority physics data was collected with a beam energy 6.5 TeV, bunch spacing 25 ns and β-functions high luminosity interaction points equal to 30 cm. In this configuration, it found through several experimental measurements that electron cloud induces significant degradation lifetime. This contribution reviews available observations, showing particular role played by e-cloud located regions around points, where two beams share same...
Timing information in current and future accelerator facilities is important for resolving objects (particle tracks, showers, etc.) extreme large particles multiplicities on the detection systems. The PICOSEC Micromegas detector has demonstrated ability to time 150\,GeV muons with a sub-25\,ps precision. Driven by detailed simulation studies phenomenological model which describes stochastically dynamics of signal formation, new designs were developed that significantly improve timing...