Search results for "Linear Energy Transfer"
showing 10 items of 18 documents
Mechanisms of Electron-Induced Single-Event Latchup
2019
In this paper, possible mechanisms by which electrons can induce single-event latchups in electronics are discussed. The energy deposition and the nuclear fragments created by electrons in silicon are analyzed in this context. The cross section enhancement effect in the presence of high-Z materials is discussed. First experimental results of electron-induced latchups are shown in static random access memory devices with low linear energy transfer thresholds. The radiation hardness assurance implications and future work are discussed.
Semi-Empirical Model for SEGR Prediction
2013
The underlying physical mechanisms in single event gate rupture (SEGR) are not known precisely. SEGR is expected to occur when the energy deposition due to a heavy ion strike exceeds a certain threshold simultaneously with sufficient electric field across the gate dielectric. Typically the energy deposition is described by using the linear energy transfer (LET) of the given ion. Previously the LET has been demonstrated not to describe the SEGR sufficiently. The work presented here introduces a semi-empirical model for the SEGR prediction based on statistical variations in the energy deposition which are described theoretically.
Radiation quality discrimination by continuous and pulse ESR techniques
2008
The biological damages produced by ionizing radiations in tissues and cells depend on the radiation quality, besides on the dose. The discrimination of the radiation quality, which is related to the linear energy transfer (LET), interests various fields such as radiobiology, astronautic space research, radiotherapy research and accidental dosimetry. In this work we have applied continuous wave ESR (cw-ESR) and pulse ESR techniques to ammonium tartrate samples with the aim of developing procedures able to discriminate radiation quality whose knowledge is fundamental for rabiobiological considerations. We have chosen the ammonium tartrate because it is a promising compound for the measurement…
Improvement of the LET sensitivity in ESR dosimetry for -photons and thermal neutrons through gadolinium addition
2007
Abstract We investigated the ESR response of new materials, alanine and ammonium tartrate to which gadolinium was added. The addition of gadolinium enhances sensitivity for Co 60 γ -photons because of its high atomic number ( Z = 64 ) and an enhancement of sensitivity for thermal neutrons because of its high thermal neutron cross section and high linear energy transfer (LET) secondary particles produced after the reaction with neutrons. In particular, in this paper we analyzed the microwave power saturation properties of dosimeters of alanine and ammonium tartrate with or without gadolinium exposed to different LET beams. The power saturation trends of dosimeters exposed to photons and to t…
Experimental Linear Energy Transfer of Heavy Ions in Silicon for RADEF Cocktail Species
2009
Experimental linear energy transfer values of heavy ions in silicon are presented with comparison to estimations from different semi empirical codes widely used among the community. This paper completes the experimental LET data for the RADEF cocktail ions in silicon.
Pigment−Pigment and Pigment−Protein Interactions in Recombinant Water-Soluble Chlorophyll Proteins (WSCP) from Cauliflower
2007
Plants contain water-soluble chlorophyll-binding proteins (WSCPs) that function neither as antennas nor as components of light-induced electron transfer of photosynthesis but are likely constituents of regulatory protective pathways in particular under stress conditions. This study presents results on the spectroscopic properties of recombinant WSCP from cauliflower reconstituted with chlorophyll b (Chl b) alone or with mixtures of Chl a and Chl b. Two types of experiments were performed: (a) measurements of stationary absorption spectra at 77 and 298 K and CD spectra at 298 K and (b) monitoring of laser flash-induced transient absorption changes with a resolution of 200 fs in the time doma…
High resistance to X-rays and therapeutic carbon ions in glioblastoma cells bearing dysfunctional ATM associates with intrinsic chromosomal instabili…
2014
To investigate chromosomal instability and radiation response mechanisms in glioblastoma cells.We undertook a comparative analysis of two patient-derived glioblastoma cell lines. Their resistance to low and high linear energy transfer (LET) radiation was assessed using clonogenic survival assay and their intrinsic chromosome instability status using fluorescence in situ hybridization. DNA damage was analyzed by pulsed-field gel electrophoresis and by γ-H2AX foci quantification. Expression of DNA damage response proteins was assessed by immunoblot.Increased radioresistance to X-rays as well as carbon ions was observed in glioblastoma cells exhibiting high levels of naturally occurring chromo…
Discrimination of Radiation Quality Through Second Harmonic Out-of-Phase cw-ESR Detection
2014
The ability to discriminate the quality of ionizing radiation is important because the biological effects produced in tissue strongly depends on both absorbed dose and linear energy transfer (LET) of ionizing particles. Here we present an experimental electron spin resonance (ESR) analysis aimed at discriminating the effective LETs of various radiation beams (e.g., 19.3 MeV protons, 60Co photons and thermal neutrons). The measurement of the intensities of the continuous wave spectrometer signal channel first harmonic in-phase and the second harmonic out-of-phase components are used to distinguish the radiation quality. A computational analysis, was carried out to evaluate the dependence of …
RADICAL DISTRIBUTIONS IN AMMONIUM TARTRATE SINGLE CRYSTALS EXPOSED TO PHOTON AND NEUTRON BEAMS
2014
The radiation therapy carried out by means of heavy charged particles (such as carbon ions) and neutrons is rapidly becoming widespread worldwide. The success of these radiation therapies relies on the high density of energy released by these particles or by secondary particles produced after primary interaction with matter. The biological damages produced by ionising radiations in tissues and cells depend more properly on the energy released per unit pathlength, which is the linear energy transfer and which determines the radiation quality. To improve the therapy effectiveness, it is necessary to grasp the mechanisms of free radical production and distribution after irradiation with these …
Toward a wave turbulence formulation of statistical nonlinear optics
2012
International audience; During this last decade, several remarkable phenomena inherent to the nonlinear propagation of incoherent optical waves have been reported in the literature. This article is aimed at providing a generalized wave turbulence kinetic formulation of random nonlinear waves governed by the nonlinear Schrodinger equation in the presence of a nonlocal or a noninstantaneous nonlinear response function. Depending on the amount of nonlocal (noninstantaneous) nonlinear interaction and the amount of inhomogeneous (nonstationary) statistics of the incoherent wave, different types of kinetic equations are obtained. In the spatial domain, when the incoherent wave exhibits fluctuatio…