On radiation damage of scintillating organic fibres in dependence on energetic electron bombardment

2002 ◽  
Author(s):  
H.A. Klose ◽  
M. Krause ◽  
W. Pfeiffer ◽  
J. Rauchfuss ◽  
G. Sinn ◽  
...  
Keyword(s):  
Radiation Damage ◽  
Energetic Electron ◽  
Electron Bombardment

Variability in the Energetic Electron Bombardment of Ganymede

2020 ◽  
Vol 125 (9) ◽  
Author(s):  
Lucas Liuzzo ◽  
Andrew R. Poppe ◽  
Christopher Paranicas ◽  
Quentin Nénon ◽  
Shahab Fatemi ◽  
...  
Keyword(s):  
Energetic Electron ◽  
Electron Bombardment

scholarly journals A case study of a sporadic sodium layer observed by the ALOMAR Weber Na lidar

2008 ◽  
Vol 26 (5) ◽  
pp. 1071-1081 ◽  
Author(s):  
H. Nesse ◽  
D. Heinrich ◽  
B. Williams ◽  
U.-P. Hoppe ◽  
J. Stadsnes ◽  
...  
Keyword(s):  
Energetic Electron ◽  
Electron Bombardment ◽  
Meteor Radar ◽  
Temperature Dependent ◽  
Sodium Layer ◽  
Sporadic E Layers ◽  
Meteoric Smoke ◽  
Sporadic E ◽  
Dependent Mechanism

Abstract. Several possible mechanisms for the production of sporadic sodium layers have been discussed in the literature, but none of them seem to explain all the accumulated observations. The hypotheses range from direct meteoric input, to energetic electron bombardment on meteoric smoke particles, to ion neutralization, to temperature dependent chemistry. The varied instrumentation located on Andøya and near Tromsø in Norway gives us an opportunity to test the different theories applied to high latitude sporadic sodium layers. We use the ALOMAR Weber sodium lidar to monitor the appearance and characteristics of a sporadic sodium layer that was observed on 5 November 2005. We also monitor the temperature to test the hypotheses regarding a temperature dependent mechanism. The EISCAT Tromsø Dynasonde, the ALOMAR/UiO All-sky camera and the SKiYMET meteor radar on Andøya are used to test the suggested relationships of sporadic sodium layers and sporadic E-layers, electron precipitation, and meteor deposition during this event. We find that more than one candidate is eligible to explain our observation of the sporadic sodium layer.

Radiation damage and spatial resolution in the EXELFS of inorganic materials

1996 ◽  
Vol 54 ◽  
pp. 558-559
Author(s):  
D. Haskel ◽  
M. Sarikaya ◽  
M. Qian ◽  
E. A. Stern
Keyword(s):  
Fine Structure ◽  
Energy Loss ◽  
Radiation Damage ◽  
Spatial Resolution ◽  
Energetic Electron ◽  
Electron Excitation ◽  
High Energy ◽  
Quantitative Information ◽  
Inorganic Materials ◽  
Core Electron

EXELFS, the extended energy loss fine structure superimposed on the high energy loss side past an inner-shell electron excitation in an EELS spectrum, contains quantitative information about the local structure around the scattering atom from which the core electron is excited, similar to that contained in the x ray absorption fine structure (XAFS). Main advantages of the EXELFS technique over XAFS include the relative ease in the former to study the local environments of low Z elements coupled to the higher spatial resolution, imaging and diffraction capabilities of the TEM.Radiation damage to the sample caused by the energetic electron beam, however, has been an important concern to whether EXELFS can be safely applied to study materials at the nanometer scale. To investigate this question we chose to study Al, SiC and MgO as representatives of three different classes of binding: metallic, covalent and ionic, with the belief that these should exhibit different sensitivities to different mechanisms of radiation damage and hence will be fair representatives of a wide variety of materials.

Radiation damage and charging effects of insulators in Electron Microscopy

1990 ◽  
Vol 48 (4) ◽  
pp. 796-797
Author(s):  
Jacques Cazaux ◽  
Omar Jbara ◽  
K.H. Kim
Keyword(s):  
Electron Microscopy ◽  
Electric Field ◽  
Radiation Damage ◽  
Charge Distribution ◽  
Charged Particles ◽  
Electron Bombardment ◽  
The Other ◽  
Trapping Time ◽  
Radiation Damages ◽  
Long Time

In the proliferation of papers dealing with charging effects of insulators submitted to an electron bombardment, the macroscopic consequences of charging are quite always considered without any consideration on the microscopic causes. The electric field built up and potential are only the electrostatic consequence of the trapped charge distribution, ρ(r,t), and, consequently of the trapping mechanisms of charged particles. On the other hand, the radiation damage effects are often explained by microscopic mechanisms (such as the Knotek-Feibelmann model) despite the fact that most of these radiation damages occur in insulators where a very large electric field may be established : If all the particles penetrating into the insulators where trapped for a long time the calculated electric field will reach 107 V/cm in less than one second (for a beam density of 1 μA/mm2). The above remark suggests that the (positive or negative) charged particles are not all trapped or, if they are, it is with a very short trapping time τr.)

scholarly journals Variations in Cathodoluminescent Intensity of Spacecraft Materials Exposed to Energetic Electron Bombardment

2015 ◽  
Vol 43 (11) ◽  
pp. 3948-3954 ◽  
Author(s):  
Justin Dekany ◽  
Justin Christensen ◽  
John Robert Dennison ◽  
Amberly Evans Jensen ◽  
Gregory Wilson ◽  
...  
Keyword(s):  
Energetic Electron ◽  
Electron Bombardment

scholarly journals Surface Characterization and Secondary Electron Emission Properties of Alumina Containing MgO Film on Ag-Mg-Al Alloy

Metals ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 570 ◽  
Author(s):  
Fan Zhou ◽  
Quan Zhang ◽  
Feifei Wang ◽  
Jing Wang ◽  
Yunfei Yang ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Surface Characterization ◽  
Secondary Electron ◽  
Energetic Electron ◽  
Electron Bombardment ◽  
Mg Alloy ◽  
Al Alloy ◽  
Activation Process ◽  
Low Oxygen ◽  
Electron Multiplier

Ag-Mg alloy is used as a dynode material in electron multiplier tubes due to the high secondary electron yields (δ) of the surface of MgO film. However, MgO film is readily degraded under strong electron or ion bombardment, which results in a decrease in the lifetime of devices. In this study, alumina-containing MgO films of ~50–150 nm were developed on a Ag-2Mg-2Al alloy (silver alloy containing 2 wt % Mg and 2 wt % Al) after a thermal activation process performed at 500–600 °C under low oxygen pressures of 5.0–20.0 Pa. Auger electron spectroscopy and X-ray photoelectron spectroscopy analyses reveal that the film consists of a thin layer of pure MgO and a relatively thicker layer of alumina-containing MgO located beneath the top MgO layer. The alumina-containing MgO film exhibits high δ value of 7.7 at a primary electron energy of 580 eV and a much better stability under energetic electron bombardment than pure MgO film on Ag-Mg alloy. Alumina has higher bond dissociation energy than MgO, and the presence of alumina in the film contributes to mitigating the dissociation of the MgO film under electron bombardment. The Ag-2Mg-2Al alloy with alumina-containing MgO film is a promising candidate as a dynode material for electron multiplier tubes.

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