D. H. H. Hoffmann
A5089063584- Laser-Plasma Interactions and Diagnostics
- Atomic and Molecular Physics
- Laser-induced spectroscopy and plasma
- Ion-surface interactions and analysis
- Particle accelerators and beam dynamics
- High-pressure geophysics and materials
- Dark Matter and Cosmic Phenomena
- Solid State Laser Technologies
- Nuclear Physics and Applications
- X-ray Spectroscopy and Fluorescence Analysis
- Laser Design and Applications
- Particle Detector Development and Performance
- Plasma Diagnostics and Applications
- Particle physics theoretical and experimental studies
- Magnetic confinement fusion research
- Advanced Fiber Laser Technologies
- Laser-Matter Interactions and Applications
- Semiconductor Lasers and Optical Devices
- Fusion materials and technologies
- Pulsed Power Technology Applications
- Nuclear physics research studies
- Cosmology and Gravitation Theories
- Mass Spectrometry Techniques and Applications
- Laser Material Processing Techniques
- Gyrotron and Vacuum Electronics Research
Xi'an Jiaotong University
2017-2025
Karlsruhe Institute of Technology
2025
Fraunhofer Institute for Laser Technology
2014-2024
Max Planck Institute for the History of Science
2010-2023
Technical University of Darmstadt
2011-2022
National Research Nuclear University MEPhI
2016-2021
Cambridge University Press
2010-2020
Institute of Modern Physics
2011-2020
German Center for Infection Research
2020
New York University Press
2016-2020
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,...
We have searched for solar axions or similar particles that couple to two photons by using the CERN Axion Solar Telescope (CAST) setup with improved conditions in all detectors. From absence of excess X-rays when magnet was pointing Sun, we set an upper limit on axion-photon coupling 8.8 x 10^{-11} GeV^{-1} at 95% CL m_a <~ 0.02 eV. This result is best experimental over a broad range axion masses and eV also supersedes previous derived from energy-loss arguments globular-cluster stars.
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....
Hypothetical axionlike particles with a two-photon interaction would be produced in the sun by Primakoff process. In laboratory magnetic field ("axion helioscope"), they transformed into x-rays energies of few keV. Using decommissioned Large Hadron Collider test magnet, CERN Axion Solar Telescope ran for about 6 months during 2003. The first results from analysis these data are presented here. No signal above background was observed, implying an upper limit to axion-photon coupling...
Intense heavy ion beams from the Gesellschaft für Schwerionenforschung (GSI, Darmstadt, Germany) accelerator facilities, together with two high energy laser systems: petawatt for experiments (PHELIX) and nanosecond (NHELIX) are a unique combination to facilitate pioneering beam-plasma interaction experiments, generate probe high-energy-density (HED) matter address basic physics issues associated driven inertial confinement fusion. In one class of will be used plasma beam study loss energetic...
We have searched for solar axions or other pseudoscalar particles that couple to two photons by using the CERN Axion Solar Telescope (CAST) setup. Whereas we previously reported results from CAST with evacuated magnet bores (Phase I), setting limits on lower mass axions, here report where were filled 4He gas II) of variable pressure. The introduction generates a refractive photon mγ, thereby achieving maximum possible conversion rate those axion masses ma match mγ. With 160 different...
At the Helmholtz center GSI, PHELIX (Petawatt High Energy Laser for heavy Ion eXperiments) has been commissioned operation in stand-alone mode and, combination with ions accelerated up to an energy of 13 MeV/u by ion accelerator UNILAC. The heavy-ion beams available at GSI enables a large variety unique experiments. Novel research opportunities are spanning from study ion–matter interaction, through challenging new experiments atomic physics, nuclear and astrophysics, into field relativistic...
The energy loss in a plasma target was measured for different heavy-ion species, ranging from $^{40}\mathrm{Ca}$ to $^{238}\mathrm{U}$ at an of 1.4 MeV/u. A discharge tube used generate hydrogen with high degree ionization and temperatures between 1 2 eV. An on-line diagnostic the performed measure free-electron density electron temperature. Compared neutral same particle density, shows enhanced stopping power due increased transfer free electrons, higher effective charge projectiles inside...
The CERN Axion Solar Telescope (CAST) has extended its search for solar axions by using 3He as a buffer gas. At T=1.8 K this allows larger pressure settings and hence sensitivity to higher axion masses than our previous measurements with 4He. With about 1 h of data taking at each 252 different we have scanned the mass range 0.39 eV < m_a 0.64 eV. From absence excess X-rays when magnet was pointing Sun set typical upper limit on axion-photon coupling g_ag 2.3 x 10^{-10} GeV^{-1} 95% CL, exact...
We study the feasibility of a new generation axion helioscope, most ambitious and promising detector solar axions to date. show that large improvements in magnetic field volume, x-ray focusing optics backgrounds are possible beyond those achieved CERN Axion Solar Telescope (CAST). For hadronic models, sensitivity axion-photon coupling gaγ ≳ few × 10−12 GeV−1 is conceivable, 1–1.5 orders magnitude CAST sensitivity. If also couple electrons, Sun produces larger flux for same value Peccei-Quinn...
The CERN Axion Solar Telescope has finished its search for solar axions with (3)He buffer gas, covering the range 0.64 eV ≲ ma 1.17 eV. This closes gap to cosmological hot dark matter limit and actually overlaps it. From absence of excess x rays when magnet was pointing Sun we set a typical upper on axion-photon coupling gaγ 3.3 × 10(-10) GeV(-1) at 95% C.L., exact value depending pressure setting. Future direct axion searches will focus increasing sensitivity smaller values gaγ, example by...
The Innoslab amplifier comprises a diode-laser partially end-pumped thin slab crystal and folded single-pass optical amplification path. While this configuration differs in many respects from other amplifiers, it shares characteristics with rod amplifiers. It combines outstanding thermal management, efficiency, beam quality the 100 W to 1 kW power range. In paper, we review amplifiers for wide range of operation regimes laser materials.
We review the development of High Energy Density Physics (HEDP) with intense heavy ion beams as a tool to induce extreme states matter. The this field connects intimately advances in accelerator physics and technology. will cover generation starting from source follow acceleration process transport target. Intensity limitations potential solutions overcome these are discussed. This is exemplified by citing examples existing machines at Gesellschaft für Schwerionenforschung (GSI-Darmstadt),...
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...
The subject of high-energy-density (HED) states in matter is considerable importance to numerous branches basic as well applied physics. Intense heavy-ion beams are an excellent tool create large samples HED the laboratory with fairly uniform physical conditions. Gesellschaft für Schwerionenforschung, Darmstadt, a unique worldwide that has synchrotron, SIS18, delivers intense energetic heavy ions. Construction much more powerful SIS100, at future international facility for antiprotons and...
Experiments are presented which demonstrate, for the first time, extreme stopping power of fully ionized hydrogen plasma low-energy (45 keV/u) heavy ions. The was created by an electrical discharge in a 20 cm long quartz tube, producing electron densities up to 7 \ifmmode\times\else\texttimes\fi{} ${10}^{16}$ ${\mathrm{cm}}^{\ensuremath{-}3}$ at temperatures well above 1 eV. In described experiment 1080 MeV/(mg/${\mathrm{cm}}^{2}$) measured using krypton ions, exceeds corresponding value...
An analytical model for the linear Richtmyer-Meshkov instability in solids under conditions of high-energy density is presented, order to describe evolution small perturbations at solid-vacuum interface. The shows that plasticity determines maximum perturbation amplitude and provides simple scaling laws it as well time when reached. After reached, interface remains oscillating with a period determined by elastic shear modulus. Extensive two-dimensional simulations are presented show...
In non-hadronic axion models, which have a tree-level axion-electron interaction, the Sun produces strong flux by bremsstrahlung, Compton scattering, and axio-recombination, ``BCA processes.'' Based on new calculation of this flux, including for first time we derive limits Yukawa coupling gae axion-photon interaction strength gaγ using CAST phase-I data (vacuum phase). For ma≲10 meV/c2 find < 8.1 × 10−23 GeV−1 at 95% CL. We stress that next-generation helioscope such as proposed IAXO could...
We present an analytical model for the Rayleigh-Taylor instability that allows approximate but still very accurate and appealing description of physics in linear regime. The is based on second law Newton it has been developed with aim dealing accelerated elastic solids. It yields asymptotic growth rate also describes initial transient phase determined by conditions. have applied to solid/solid solid/fluid interfaces arbitrary Atwood numbers. results are excellent agreement previous models...
This Letter reports on the measurement of energy loss and projectile charge states argon ions at an 4 MeV/u penetrating a fully ionized carbon plasma. The plasma n(e)≈10(20) cm(-3) T(e)≈180 eV is created by two laser beams λ(Las)=532 nm incident from opposite sides thin foil. resulting spatially homogenous allows us to record precise experimental data. data show increase factor 2 in stopping power which very good agreement with specifically developed Monte Carlo code, that calculation heavy...
The CERN Axion Solar Telescope (CAST) searches for $a\ensuremath{\rightarrow}\ensuremath{\gamma}$ conversion in the 9 T magnetic field of a refurbished LHC test magnet that can be directed toward Sun. Two parallel bores filled with helium adjustable pressure to match x-ray refractive mass ${m}_{\ensuremath{\gamma}}$ axion search ${m}_{a}$. After vacuum phase (2003--2004), which is optimal ${m}_{a}\ensuremath{\lesssim}0.02\text{ }\text{ }\mathrm{eV}$, we used $^{4}\mathrm{He}$ 2005--2007...
Abstract Intense particle beams generated from the interaction of ultrahigh intensity lasers with sample foils provide options in radiography, high-yield neutron sources, high-energy-density-matter generation, and ion fast ignition. An accurate understanding beam transportation behavior dense matter is crucial for all these applications. Here we report experimental evidence on one order magnitude enhancement intense laser-accelerated proton stopping ionized matter, comparison current-widely...