Search results for "plasma physics"

Large Impact of the Decay of Niobium Isomers on the Reactor ν¯e Summation Calculations

2019

Even mass neutron-rich niobium isotopes are among the principal contributors to the reactor antineutrino energy spectrum. They are also among the most challenging to measure due to the refractory nature of niobium, and because they exhibit isomeric states lying very close in energy. The beta-intensity distributions of Nb-100gs,Nb-100m and Nb-102gs,Nb-02m beta decays have been determined using the total absorption.-ray spectroscopy technique. The measurements were performed at the upgraded Ion Guide Isotope Separator On-Line facility at the University of Jyvaskyla. Here, the double Penning trap system JYFLTRAP was employed to disentangle the beta decay of the isomeric states. The new data ob…

The X-Ray Dark Side of Venus AND  The Study of Hot Electrons in Shock Ignition relevant Regime

Laboratory evidence for proton energization by collisionless shock surfing

2021

Charged particles can be accelerated to high energies by collisionless shock waves in astrophysical environments, such as supernova remnants. By interacting with the magnetized ambient medium, these shocks can transfer energy to particles. Despite increasing efforts in the characterization of these shocks from satellite measurements at Earth’s bow shock as well as powerful numerical simulations, the underlying acceleration mechanism or a combination thereof is still widely debated. Here we show that astrophysically relevant super-critical quasi-perpendicular magnetized collisionless shocks can be produced and characterized in the laboratory. We observe the characteristics of super-criticali…

Production of highly charged ions of rare species by laser-induced desorption inside an electron beam ion trap

2019

This paper reports on the development and testing of a novel, highly efficient technique for the injection of very rare species into electron beam ion traps (EBITs) for the production of highly charged ions (HCI). It relies on in-trap laser-induced desorption of atoms from a sample brought very close to the electron beam resulting in a very high capture efficiency in the EBIT. We have demonstrated a steady production of HCI of the stable isotope 165Ho from samples of only 1012 atoms (∼300 pg) in charge states up to 45+. HCI of these species can be subsequently extracted for use in other experiments or stored in the trapping volume of the EBIT for spectroscopic measurements. The high efficie…

Suppression of Penning discharges between the KATRIN spectrometers

2020

The KArlsruhe TRItium Neutrino experiment (KATRIN) aims to determine the effective electron (anti)neutrino mass with a sensitivity of $0.2\textrm{ eV/c}^2$ (90$\%$ C.L.) by precisely measuring the endpoint region of the tritium $\beta$-decay spectrum. It uses a tandem of electrostatic spectrometers working as MAC-E (magnetic adiabatic collimation combined with an electrostatic) filters. In the space between the pre-spectrometer and the main spectrometer, an unavoidable Penning trap is created when the superconducting magnet between the two spectrometers, biased at their respective nominal potentials, is energized. The electrons accumulated in this trap can lead to discharges, which create a…

Tracing the ICME plasma with a MHD simulation

2021

The determination of the chemical composition of interplanetary coronal mass ejection (ICME) plasma is an open issue. More specifically, it is not yet fully understood how remote sensing observations of the solar corona plasma during solar disturbances evolve into plasma properties measured in situ away from the Sun. The ambient conditions of the background interplanetary plasma are important for space weather because they influence the evolutions, arrival times, and geo-effectiveness of the disturbances. The Reverse In situ and MHD APproach (RIMAP) is a technique to reconstruct the heliosphere on the ecliptic plane (including the magnetic Parker spiral) directly from in situ measurements a…

A new measurement of direct CP violation in the neutral kaon system

1993

A new measurement of the ratio of the CP-violating amplitudes for $K_{L} \to 2\pi^{0}$ and $K_{L} \to \pi^{+}\pi^{-}$ is reported. The measured value for $\Re = |\eta_{00} / \eta_{ +-}|^{2}$ is $0.9878 \pm 0.0026 \pm 0.0030$, where the first error is the statistical uncertainty and the second is the estimate of the systematic uncertainty. This gives a value for the parameter describing direct CP violation: $\Re$ $\epsilon'/\epsilon = (2.0 \pm 0.7) \times 10^{−3}$ .

Overview of first Wendelstein 7-X high-performance operation

2019

Abstract The optimized superconducting stellarator device Wendelstein 7-X (with major radius , minor radius , and plasma volume) restarted operation after the assembly of a graphite heat shield and 10 inertially cooled island divertor modules. This paper reports on the results from the first high-performance plasma operation. Glow discharge conditioning and ECRH conditioning discharges in helium turned out to be important for density and edge radiation control. Plasma densities of with central electron temperatures were routinely achieved with hydrogen gas fueling, frequently terminated by a radiative collapse. In a first stage, plasma densities up to were reached with hydrogen pellet injec…

Simulating pump-probe photo-electron and absorption spectroscopy on the attosecond time-scale with time-dependent density-functional theory

2013

Molecular absorption and photoelectron spectra can be efficiently predicted with real-time time-dependent density functional theory. We show herein how these techniques can be easily extended to study time-resolved pump-probe experiments, in which a system response (absorption or electron emission) to a probe pulse is measured in an excited state. This simulation tool helps with the interpretation of fast-evolving attosecond time-resolved spectroscopic experiments, in which electronic motion must be followed at its natural timescale. We show how the extra degrees of freedom (pump-pulse duration, intensity, frequency, and time delay), which are absent in a conventional steady-state experimen…

Trajectory bending and energy spreading of charged ions in time-of-flight telescopes used for ion beam analysis

2014

Carbon foil time pick-up detectors are widely used in pairs in ion beam applications as time-of-flight detectors. These detectors are suitable for a wide energy range and for all ions but at the lowest energies the tandem effect limits the achievable time of flight and therefore the energy resolution. Tandem effect occurs when an ion passes the first carbon foil of the timing detector and its charge state is changed. As the carbon foil of the first timing detector has often a non-zero voltage the ion can accelerate or decelerate before and after the timing detector. The combination of different charge state properties before and after the carbon foil now induces spread to the measured times…