scholarly journals Development of ion recoil energy distributions in the Coulomb explosion of argon clusters resolved by charge-state selective ion energy spectroscopy

2021 ◽  
Author(s):  
D. Komar ◽  
L. Kazak ◽  
K-H. Meiwes-Broer ◽  
J. Tiggesbäumker
Keyword(s):  
High Energy ◽  
Coulomb Explosion ◽  
Energy Spectra ◽  
Recoil Energy ◽  
Energy Distributions ◽  
Ion Energy ◽  
Argon Clusters ◽  
High Energy Tail ◽  
Charge States ◽  
The Individual

AbstractThe laser intensity dependence of the recoil energies from the Coulomb explosion of small argon clusters has been investigated by resolving the contributions of the individual charge states to the ion recoil energy spectra. Between $$10^{14}$$ 10 14 and $$10^{15}$$ 10 15 W/cm$$^2$$ 2 , the high-energy tail of the ion energy spectra changes its shape and develops into the well-known knee feature, which results from the cluster size distribution, laser focal averaging, and ionization saturation. Resolving the contributions of the different charge states to the recoil energies, the experimental data reveal that the basic assumption of an exploding homogeneously charged sphere cannot be maintained in general. In fact, the energy spectra of the high-q show distinct gaps in the yields at low kinetic energies, which hints at more complex radial ion charge distributions developing during the laser pulse impact.

scholarly journals Nuclear disintegrations produced by cosmic rays

1949 ◽  
Vol 196 (1046) ◽  
pp. 325-343 ◽  
Keyword(s):  
Cosmic Radiation ◽  
High Energy ◽  
Energy Spectra ◽  
Angular Distributions ◽  
Excitation Energies ◽  
Wide Range ◽  
High Energy Tail ◽  
Energy And Angular Distributions ◽  
Photographic Emulsions ◽  
Α Particles

Measurements have been made on the energy and angular distributions of the charged particles from disintegration ‘stars’ produced in the silver and bromine nuclei of photographic emulsions exposed to cosmic radiation. The observations extended over a wide range of excitation energies (100 to 700 MeV). The energy spectra and angular distributions of the protons can be explained in all cases by simple evaporation theory. This energy distribution shows also a high-energy tail consisting of direct knock-on protons and slow mesons. At high excitation energies the α-particles exhibit collimation effects which are probably due to localized ‘boiling’ or a form of fission.

scholarly journals Reception of Modulated Neutrino Day-Night Effect Signal by Neutrino Detectors

2019 ◽  
Vol 201 ◽  
pp. 09005
Author(s):  
Oleg Kharlanov
Keyword(s):  
High Energy ◽  
Solar Neutrinos ◽  
Neutrino Energy ◽  
Time Of Day ◽  
Recoil Energy ◽  
Neutrino Detectors ◽  
High Energy Tail ◽  
Weighted Data ◽  
Regeneration Effect ◽  
Neutrino Experiments

The regeneration effect of solar neutrinos in the Earth leading to the so-called day-night effect strongly depends on the neutrino energy, the time of day, and the season. Classical neutrino experiments, such as Super-Kamiokande, typically observe this effect cumulatively, i.e., virtually integrate it over the year. We discuss various day-night effects that could become potentially observable if time-weighted data processing is applied to neutrino events. The procedure is similar to reception of radio-frequency modulated signals and ‘demodulation’ of the neutrino signal, for example, is able to reveal interesting signatures in the high-energy tail of the electron recoil energy spectrum

Observation of Hot Electron Field Emission

2000 ◽  
Vol 621 ◽  
Author(s):  
Jonathan Shaw
Keyword(s):  
High Energy ◽  
Metallic State ◽  
Hot Electron ◽  
Many Body ◽  
Energy Distributions ◽  
Field Emitter Arrays ◽  
High Energy Tail ◽  
Electron Field ◽  
Gap States

ABSTRACTWe report energy distributions of silicon Field Emitter Arrays coated with 50A of ZnO. The distributions reflect changes in the ZnO conductivity induced by annealing in vacuum, temperature, and annealing in hydrogen. An additional coating of titanium performed in-situ produced large additional changes. Emission from the ZnO at energies near the Fermi level increased with gate voltage only after hydrogen annealing, when hot, and after Ti coating. In those same cases the emission distribution contained a tail at energies above EF. The highenergy emission tail is due to a many-body or Auger process whereby holes injected below EF create hot electrons. Although emission from ZnO occurred at energies up to 8eV below EF, no high-energy tail was observed in the normal case. Thus emission appears to occur from isolated electrons in ZnO gap states in cases where the distribution lacks a high-energy tail. Conversely, emission above EF suggests that emission occurred from a metallic state such as an accumulated conduction band.

scholarly journals 1,000,000 Giant Pulses from the Crab Pulsar

2017 ◽  
Vol 13 (S337) ◽  
pp. 380-381
Author(s):  
Mitchell B. Mickaliger ◽  
Ben W. Stappers ◽  
Cees G. Bassa ◽  
Aldus G. Fletcher
Keyword(s):  
Single Pulse ◽  
High Energy ◽  
Daily Basis ◽  
Large Set ◽  
Crab Pulsar ◽  
Energy Distributions ◽  
Giant Pulses ◽  
High Energy Tail ◽  
Insight Into ◽  
Shed Light

AbstractThe Crab pulsar was first detected soon after the discovery of pulsars, and has long been studied for its unique traits. One of these traits, giant pulses that can be upwards of 1000 times brighter than the average pulse, was key to the Crab’s initial detection. Giant pulses are only seen in a few pulsars, and their energy distributions distinguish them from normal pulsed emission. There have been many studies over a period of decades to measure the power-law slope of these energy distributions, which provide insight into the possible emission mechanism of these giant pulses.The 42-foot telescope at Jodrell Bank Observatory monitors the Crab pulsar on a daily basis. We have single-pulse data dating back to 2012, containing roughly 1,000,000 giant pulses, the largest sample of Crab giant pulses to date. This large set of giant pulses allows us to do a range of science, including pulse-width studies and in-depth studies of giant-pulse energy distributions. The latter are particularly interesting, as close inspection of the high-energy tail of the energy distribution allows us to investigate the detectability of extragalactic giant-pulsing pulsars. Also, by calculating rates from these energy distributions, we may be able to shed light on a possible link between Fast Radio Bursts and giant pulses.

ENERGY AND ANGULAR DISTRIBUTIONS OF PHOTONEUTRONS PRODUCED BY 70-MEV. X-RAYS

1955 ◽  
Vol 33 (12) ◽  
pp. 785-796 ◽  
Author(s):  
W. R. Dixon
Keyword(s):  
High Energy ◽  
Zinc Sulphide ◽  
Angular Distributions ◽  
X Rays ◽  
Evaporation Process ◽  
Light Elements ◽  
Energy Distributions ◽  
High Energy Tail ◽  
Nuclear Temperature ◽  
Energy And Angular Distributions

The angular distributions of the photoneutrons produced by 70-Mev. X-rays in seven elements have been measured with a zinc sulphide – lucite scintillation detector. For the heavy elements the distributions are essentially isotropic, indicating the predominance of the evaporation process, while for the light elements there is also an anisotropic component peaked at 90°. The energy distributions of the photoneutrons produced in copper and lead targets have been determined with nuclear emulsions. It is shown that most of the neutrons can be attributed to an evaporation process which is governed by a constant nuclear temperature, the temperature found for copper being 1.2 Mev., and for lead being 1.0 Mev. A high-energy tail on the energy distributions is attributed to direct interactions.

scholarly journals Non-Maxwellian rate coefficients for electron and ion collisions in Rydberg plasmas: implications for excitation and ionization

2020 ◽  
Vol 86 (3) ◽  
Author(s):  
Daniel Vrinceanu ◽  
Roberto Onofrio ◽  
H. R. Sadeghpour
Keyword(s):  
Principal Quantum Number ◽  
Charged Particles ◽  
High Energy ◽  
Rate Coefficients ◽  
Hydrogen Atoms ◽  
Energy Distributions ◽  
Ion Collisions ◽  
Laboratory Plasmas ◽  
High Energy Tail ◽  
Collisional Rate Coefficients

Scattering phenomena between charged particles and highly excited Rydberg atoms are of critical importance in many processes in plasma physics and astrophysics. While a Maxwell–Boltzmann (MB) energy distribution for the charged particles is often assumed for calculations of collisional rate coefficients, in this contribution we relax this assumption and use two different energy distributions, a bimodal MB distribution and a $\unicode[STIX]{x1D705}$ -distribution. Both variants share a high-energy tails occurring with higher probability than the corresponding MB distribution. The high-energy tail may significantly affect rate coefficients for various processes. We focus the analysis to specific situations by showing the dependence of the rate coefficients on the principal quantum number of hydrogen atoms in $n$ -changing collisions with electrons in the excitation and ionization channels and in a temperature range relevant to the divertor region of a tokamak device. We finally discuss the implications for diagnostics of laboratory plasmas.

scholarly journals Optimization for deuterium ion acceleration in foam targets by ultra-intense lasers

2010 ◽  
Vol 28 (2) ◽  
pp. 333-341 ◽  
Author(s):  
M.A. Bari ◽  
Z.M. Sheng ◽  
W.M. Wang ◽  
Y.T. Li ◽  
M. Salahuddin ◽  
...  
Keyword(s):  
High Energy ◽  
Hot Electrons ◽  
Energy Spectra ◽  
Ion Acceleration ◽  
Optimal Angle ◽  
Ion Energy ◽  
Particle In Cell ◽  
Laser Parameters ◽  
Target Composition ◽  
Electrostatic Fields

AbstractIn this article, we investigate the effects of foam target composition and laser parameters on deuterium ion energy spectra with particle-in-cell simulations. We find that localized electrostatic fields with multi peaks around the surfaces of lamellar layers inside foam target are induced. These fields accelerate deuterium ions from thin foam layers by restricting the flow of hot electrons. This mechanism of ion acceleration called as bulk ion acceleration generates large number of high energy deuterium ions. Deuterons inside foam target are accelerated up to 126 MeV in case of oblique optimal angle of 30° where it is much greater than the normal laser incidence energy of 88 MeV.

Charge Collection Properties of 6H-SiC Diodes by Wide Variety of Charged Particles up to Several Hundreds MeV

2009 ◽  
Vol 615-617 ◽  
pp. 861-864 ◽  
Author(s):  
Shinobu Onoda ◽  
Naoya Iwamoto ◽  
Makoto Murakami ◽  
Takeshi Ohshima ◽  
Toshio Hirao ◽  
...  
Keyword(s):  
Heavy Ions ◽  
Charged Particles ◽  
Pulse Height ◽  
High Energy ◽  
Energy Spectra ◽  
Charge Collection ◽  
Ion Energy

We investigated the energy spectra in p+n 6H-SiC diodes by a wide variety of charged particles with energies up to several hundred MeV. Though Pulse Height Defect (PHD) was detected when the samples were irradiated with high energy heavy ions (322MeV-Kr and 454MeV-Xe), linearity between pulse height (peak channel) and ion energy up to 150MeV was observed.

Observation of a high-energy tail in ion energy distribution in the cylindrical Hall thruster plasma

2014 ◽  
Vol 21 (10) ◽  
pp. 103502 ◽  
Author(s):  
Youbong Lim ◽  
Holak Kim ◽  
Wonho Choe ◽  
Seung Hun Lee ◽  
Jongho Seon ◽  
...  
Keyword(s):  
Energy Distribution ◽  
High Energy ◽  
Hall Thruster ◽  
Ion Energy ◽  
Ion Energy Distribution ◽  
High Energy Tail

scholarly journals Effects of electron distribution anisotropy in spectroscopic diagnostics of solar flares

2018 ◽  
Vol 618 ◽  
pp. A176 ◽  
Author(s):  
E. Dzifčáková ◽  
M. Karlický
Keyword(s):  
Electron Distribution ◽  
High Energy ◽  
Maxwellian Distribution ◽  
Temperature Anisotropy ◽  
Energy Distributions ◽  
Ionization Equilibrium ◽  
Line Intensities ◽  
Relative Line ◽  
High Energy Tail ◽  
Temperature Diagnostics

Aims. We analyzed effects of the bi-Maxwellian electron distribution representing electron temperature anisotropy along and across the magnetic field on the ionization and excitation equilibrium with consequences on the temperature diagnostics of the flare plasma. Methods. The bi-Maxwellian energy distributions were calculated numerically. Synthetic X-ray line spectra of the bi-Maxwellian distributions were calculated using non-Maxwellian ionization, recombination, excitation and de-excitation rates. Results. We found that the anisotropic bi-Maxwellian velocity distributions transform to the nonthermal energy distributions with a high-energy tail. Their maximum is shifted to lower energies and contains a higher number of the low-energy particles in comparison with the Maxwellian one. Increasing the deviation of the parameter p = T∥/T⊥ from 1, changes the shape of bi-Maxwellian distributions and ionization equilibrium, and relative line intensities also increase. The effects are more significant for the bi-Maxwellian distribution with T∥ > T⊥. Moreover, considering different acceleration mechanisms and collisional isotropization it is possible that the bi-Maxwellian distributions with high deviations from the Maxwellian distribution are more probable for those with p >  1 than for those with p <  1. Therefore, distributions with p >  1 can be much more easily diagnosed than those with p <  1. Furthermore, we compared the effects of the bi-Maxwellian distributions on the ionization equilibrium and temperature diagnostics with those for the κ-distributions obtained previously. We found that they are similar and at the present state it is difficult to distinguish between the bi-Maxwellian and κ-distributions from the line ratios.

Sign in / Sign up

Export Citation Format

Share Document