F. Caspers
A5056374875- Particle Accelerators and Free-Electron Lasers
- Particle accelerators and beam dynamics
- Superconducting Materials and Applications
- Gyrotron and Vacuum Electronics Research
- Dark Matter and Cosmic Phenomena
- Particle Detector Development and Performance
- Atomic and Subatomic Physics Research
- Particle physics theoretical and experimental studies
- Microwave and Dielectric Measurement Techniques
- Microwave Engineering and Waveguides
- Electromagnetic Compatibility and Measurements
- Electromagnetic Simulation and Numerical Methods
- Cold Atom Physics and Bose-Einstein Condensates
- Cosmology and Gravitation Theories
- Electrostatic Discharge in Electronics
- Quantum, superfluid, helium dynamics
- Radio Frequency Integrated Circuit Design
- Astrophysics and Cosmic Phenomena
- Energy Harvesting in Wireless Networks
- Heat Transfer and Optimization
- Semiconductor Lasers and Optical Devices
- Magnetic confinement fusion research
- Advanced Antenna and Metasurface Technologies
- Photonic and Optical Devices
- Electromagnetic Compatibility and Noise Suppression
European Organization for Nuclear Research
2014-2024
ESI Group (France)
2021
The International Axion Observatory (IAXO) will be a forth generation axion helioscope. As its primary physics goal, IAXO look for axions or axion-like particles (ALPs) originating in the Sun via Primakoff conversion of solar plasma photons. In terms signal-to-noise ratio, about 4–5 orders magnitude more sensitive than CAST, currently most powerful helioscope, reaching sensitivity to axion-photon couplings down few × 10−12 GeV−1 and thus probing large fraction unexplored ALP parameter space....
The Center for Axion and Precision Physics Research at the Institute Basic Science is searching axion dark matter using ultralow temperature microwave resonators. We report exclusion of mass range $10.7126--10.7186\text{ }\text{ }\ensuremath{\mu}\mathrm{eV}$ with near Kim-Shifman-Vainshtein-Zakharov (KSVZ) coupling sensitivity $10.16--11.37\text{ about 9 times larger 90% confidence level. This first search result in these ranges. It also a resonator physical less than 40 mK.
The CERN Resonant WISP Search (CROWS) probes the existence of Weakly Interacting Sub-eV Particles (WISPs) like axions or hidden sector photons. It is based on principle an optical light shining through wall experiment, adapted to microwaves. Critical aspects experiment are electromagnetic shielding, design and operation low loss cavity resonators detection weak sinusoidal microwave signals. Lower bounds were set coupling constant $g = 4.5 \cdot 10^{-8} $GeV$^{-1}$ for axion particles with a...
A bstract We present results of the Relic Axion Dark-Matter Exploratory Setup (RADES), a detector which is part CERN Solar Telescope (CAST), searching for axion dark matter in 34.67 μ eV mass range. radio frequency cavity consisting 5 sub-cavities coupled by inductive irises took physics data inside CAST dipole magnet first time using this filter-like haloscope geometry. An exclusion limit with 95% credibility level on axion-photon coupling constant g aγ ≳ 4 × 10 − 13 GeV 1 over range 34 ....
The CAST-CAPP axion haloscope, operating at CERN inside the CAST dipole magnet, has searched for axions in 19.74 $\mu$eV to 22.47 mass range. detection concept follows Sikivie haloscope principle, where Dark Matter convert into photons within a resonator immersed magnetic field. is an array of four individual rectangular cavities inserted strong phase-matched maximize sensitivity. Here we report on data acquired 4124 h from 2019 2021. Each cavity equipped with fast frequency tuning mechanism...
In this work, we consider searches for dark matter made of axions or axionlike particles using resonant radio frequency cavities inserted into dipole magnets from particle accelerators, wiggler developed accelerator based advanced light sources, and toroidal similar to those used in particle-physics detectors. We investigate the expected sensitivity such axionlike-particle dark-matter detectors discuss engineering aspects building tuning them. Brief mention is also even stronger field which...
Hypothetical axions provide a compelling explanation for dark matter and could be emitted from the hot solar interior. The CERN Axion Solar Telescope has been searching via their back conversion to x-ray photons in 9-T 10-m long magnet directed toward Sun. We report on an extended run with International Observatory pathfinder detector, doubling previous exposure time. detector was operated xenon-based gas mixture part of new run, providing technical insights future configurations. No counts...
Using microwave cavities one can build a resonant ``microwave-shining-through-walls'' experiment to search for hidden sector photons and axion like particles, predicted in many extensions of the standard model. In this note we make feasibility study sensitivities which be reached using state art technology.
The concept of describing RF circuits in terms waves is discussed and the S-matrix related matrices are defined. signal flow graph (SFG) introduced as a graphical means to visualize how propagate an network. properties most relevant passive devices (hybrids, couplers, non-reciprocal elements, etc.) delineated corresponding S-parameters given. For microwave integrated (MICs) planar transmission lines such microstrip line have become very important.
The main aim of this paper is the analysis feasibility employing permanent magnets for multipactor mitigation in a coaxial waveguide.First, study line immersed uniform axial magnetic field shows that can be suppressed at any RF frequency if external strong enough.Both theoretical simulations and experimental tests validate statement.Next, breakdown hollow cylindrical magnet analyzed.Numerical show certain range.The performed test campaign demonstrates capability to avoid electron...
The prediction of the transverse wall beam impedance at first unstable betatron line (8 kHz) CERN Large Hadron Collider (LHC) is paramount importance for understanding and controlling related coupled-bunch instabilities. Until now only novel analytical formulas were available this frequency. Recently, laboratory measurements numerical simulations performed to cross-check predictions. experimental results based on measurement variation a probe coil inductance in presence (i) sample graphite...
We describe a dedicated electron cloud experiment which was installed in the CERN Proton Synchrotron 2007. The setup comprises shielded button-type pickups, fast vacuum logging, dipole magnet, and stripline electrode to experimentally verify beneficial effect of clearing. observed within last milliseconds before ejection nominal LHC proton beam consisting 72 bunches with 25 ns spacing. Measurements flux at wall pressure are presented for set magnetic fields bias voltages on clearing...
The International Axion Observatory (IAXO) is a proposed 4th-generation axion helioscope with the primary physics research goal to search for solar axions via their Primakoff conversion into photons of 1 – 10 keV energies in strong magnetic field. IAXO will achieve sensitivity axion-photon coupling gaγ down few ×10−12 GeV−1 wide range masses up ∼ 0.25 eV. This an improvement over currently best (3rd generation) helioscope, CERN Solar Telescope (CAST), about 5 orders magnitude signal...
The transverse impedance in the LHC is expected to be dominated by numerous collimators, most of which are made Fibre-Reinforced-Carbon withstand impacts high intensity proton beams case failures, and will moved very close beam, with full gaps few millimetres, order protect surrounding super-conducting equipments. We present an estimate resistive-wall total at injection top energy, induced coupled-bunch growth rates tune shifts, finally result comparison theoretical predictions measurements...
The Smith chart is a very valuable and important tool that facilitates interpretation of S-parameter measurements. This paper will give brief overview on why more importantly how to use the chart. Its definition as well an introduction navigate inside are illustrated. Useful examples show broad possibilities for in variety applications.
In this work, we describe the latest results for measurements of hyperfine structure antiprotonic 3He. Two out four measurable super–super-hyperfine (SSHF) transition lines (n, L) = (36, 34) state 3He were observed. The measured frequencies individual transitions are 11.125 48(08) GHz and 11.157 93(13) GHz, with increased precisions about 43% 25%, respectively, compared to our first (Friedreich et al 2011 Phys. Lett. B 700 1–6). They less than 0.5 MHz higher respect most recent theoretical...
The two LHC injection kicker magnet systems must produce a kick of 1.3 T.m with flattop duration variable up to 7860 ns, and rise fall times less than 900 ns 3000 respectively. Each system is composed resonant charging power supplies (RCPSs) four 5 Omega transmission line magnets matched terminating resistors pulse forming networks (PFNs). A beam screen placed in the aperture magnets: consists ceramic tube conductors on inner wall. provide path for image current the, high intensity,LHC...
We report on the first experimental results for microwave spectroscopy of hyperfine structure p¯3He+. Due to helium nuclear spin, p¯3He+ has a more complex than p¯4He+, which already been studied before. Thus comparison between theoretical calculations and will provide stringent test three-body quantum electrodynamics (QED) theory. Two out four super-super-hyperfine (SSHF) transition lines (n,L)=(36,34) state were observed. The measured frequencies individual transitions are 11.12559(14) GHz...
Cavities that are partially filled with ferrite material provide a tunable resonance frequency by making use of the changing μ-characteristics ferrites when exposed to an external magnetic bias field. The concept using either parallel or perpendicular biasing reach certain cavity has been known for many years. However, based on superposition and fields obtain improved characteristics was suggested in W. R. Smythe “Reducing tuner power loss field rotation,” IEEE Trans. Nucl. Sci., vol. 30,...