نتایج جستجو برای: ionization radiation

تعداد نتایج: 273398  

2014
Wen-Ching Hsieh Hao-Tien Daniel Lee Fuh-Cheng Jong

Metal-aluminum oxide-hafnium aluminum oxide-silicon oxide-silicon (hereafter MAHAOS) devices can be candidates for ionizing radiation sensor applications. In this work, MAHAOS devices (SONOS-like structures with high k stack gate dielectric) were studied regarding the first known characterization of the ionization radiation sensing response. The change of threshold voltage V(T) for a MAHAOS dev...

2017
Karol Jan Nass

The ultrafast radiation damage begins with photoionization, followed by impact ionization by photoand Auger electrons. The ionization of atoms develops with time, ultimately causing lattice disorder and Coulomb explosion of the crystal. Due to very short pulse duration, it has been proposed that diffraction can be recorded before significant structural changes occur. This has been termed “diffr...

2002
J. McDonald

Radiation-hard ionization chambers were tested using an intense electron beam from the accelerator test facility (ATF) at the Brookhaven National Laboratory (BNL). The detectors were designed to be used as the basic element for monitoring muons in the Main Injector Neutrino beamline (NuMI) at the Fermi National Accelerator Laboratory (FNAL). Measurements of linearity of response, voltage depend...

1997
T. J. Bensky R. R. Jones

We report the first observation of ionization of Rydberg atoms by subpicosecond, circularly polarized THz radiation. The field amplitude in these pulses is non-negligible for only one-quarter of an optical cycle. The experiment is performed in the short-pulse regime, where the duration of the ionizing pulse is shorter than the classical Kepler period of the Rydberg electron. We find that the io...

2004
C. Constantin C. A. Back K. B. Fournier G. Gregori S. H. Glenzer M. C. Miller E. L. Dewald O. L. Landen

We observe a laser-driven supersonic ionization wave heating a mm-scale plasma of sub-critical density up to 2-3 keV electron temperatures. Propagation velocities initially 10 times the sound speed were measured by means of time-resolved x-ray imaging diagnostics. The measured ionization wave trajectory is modeled analytically and by a 2D radiation-hydrodynamics code. The comparison to the mode...

2004
A. Czasch T. Jahnke S. Schössler M. Hattass Th. Weber M. Weckenbrock J. Titze A. Staudte S. Kammer S. Voss R. Dörner H. Schmidt-Böcking J. M. Rost T. Schneider C. Liu

This is a report about a novel experiment on double excitation of Helium by absorption of synchrotron radiation close to the double ionization threshold at 79 eV. Partial cross-sections for single-ionization from 78.15 eV up to 78,9 eV (photon energy) with an energy resolution of 3meV have been measured. The technique described in this article allows for an angular and energy resolved measureme...

Journal: :Applied radiation and isotopes : including data, instrumentation and methods for use in agriculture, industry and medicine 2012
Jonas O Silva Linda V E Caldas

The development of new radiation detectors of low cost but with adequate materials is a very important task for countries that have to import ionization chambers such as Brazil. A special double faced ionization chamber was developed for use in conventional diagnostic radiology beams and computed tomography energy ranges. The results show that this new chamber present applicability in conventio...

C E de Almeida, L Campos, L Magalhães

Background: Radiotherapy is an important technique of cancer treatment using ionizing radiation. The determination of total dose in reference conditions is an important contribution to uncertainty that could achieve 2%. The source of this uncertainty comes from cavity theory that relates the in-air cavity dose and the dose to water. These correction factors are determined from Monte Carlo calcu...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 1998
H Fernando G A Papadantonakis N S Kim P R LeBreton

Numerous investigations have focused on DNA damage induced by ionizing radiation; however, photoionization threshold energies of nucleic acid components in aqueous solution are not known. Herein, data from gas-phase photoelectron experiments have been combined with results from self-consistent field and post-self-consistent field molecular orbital calculations and with theoretical Gibbs free en...

Journal: :Frontiers in Physics 2022

We use high-order harmonic spectroscopy to study ionization dynamics in a macroscopic target with tunable density, spanning over six orders of magnitude. In an situ pump-probe experiment, the is prepared at different densities varying degrees laser-induced ionization. High-order radiation generated pre-ionized target, and steepening decrease yield observed for increasing pre-ionization, allowin...

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