scholarly journals Simulation of Radiation Damage for Silicon Drift Detector

Sensors ◽  
2019 ◽  
Vol 19 (8) ◽  
pp. 1767 ◽  
Author(s):  
Yang Liu ◽  
Tengfei Zhu ◽  
Jianxi Yao ◽  
Xiaoping Ouyang
Keyword(s):  
Radiation Damage ◽  
Secondary Electron ◽  
High Sensitivity ◽  
Particle Energy ◽  
Space Environment ◽  
Deep Space ◽  
Silicon Drift Detector ◽  
Detector Performance ◽  
Secondary Electrons ◽  
Recoil Atoms

Silicon drift detector with high sensitivity and energy resolution is an advanced detector which is suitable to be used in deep space detection. To study and reveal the radiation damage of the silicon drift detector (SDD) in a deep-space environment, which will degrade the detector performance, in this paper, the SDD radiation damage effects and mechanics, including displacement damage and ionization damage, for irradiations of different energy of neutrons and gammas are investigated using Geant4 simulation. The results indicate the recoil atoms distribution generated by neutrons in SDD is uniform, and recoil atoms’ energy is mainly in the low energy region. For secondary particles produced by neutron irradiation, a large energy loss in inelastic scattering and fission reactions occur, and neutron has a significant nuclear reaction. The energy deposition caused by gammas irradiation is linear with the thickness of SDD; the secondary electron energy distribution produced by gamma irradiation is from several eV to incident particle energy. As the scattering angle of secondary electron increases, the number of secondary electrons decreases. Therefore, a reasonable detector epitaxial thickness should be set in the anti-irradiation design of SDD.

Effects of Space Charge on ESEM Gas Amplification

1997 ◽  
Vol 3 (S2) ◽  
pp. 609-610 ◽  
Author(s):  
B.L. Thiel ◽  
M.R. Hussein-Ismail ◽  
A.M. Donald
Keyword(s):  
Electric Field ◽  
Electrostatic Field ◽  
Secondary Electron ◽  
Sample Surface ◽  
Cascade Process ◽  
Secondary Electrons ◽  
Positive Ions ◽  
Space Charges ◽  
Cascade Amplification ◽  
Environmental Sem

We have performed a theoretical investigation of the effects of space charges in the Environmental SEM (ESEM). The ElectroScan ESEM uses an electrostatic field to cause gas cascade amplification of secondary electron signals. Previous theoretical descriptions of the gas cascade process in the ESEM have assumed that distortion of the electric field due to space charges can be neglected. This assumption has now been tested and shown to be valid.In the ElectroScan ESEM, a positively biased detector is located above the sample, creating an electric field on the order of 105 V/m between the detector and sample surface. Secondary electrons leaving the sample are cascaded though the gas, amplifying the signal and creating positive ions. Because the electrons move very quickly through the gas, they do not accumulate in the specimen-to-detector gap. However, the velocity of the positive ions is limited by diffusion.

Alpha-Recoil Damage in Thorianite and Uraninite: Effect on Dissolution and Time-Scale for Spontaneous Annealing of Damage

1984 ◽  
Vol 44 ◽  
Author(s):  
Yehuda Eyal ◽  
Robert L. Fleischer
Keyword(s):  
Radiation Damage ◽  
Time Scale ◽  
Isotopic Fractionation ◽  
Atomic Displacement ◽  
Enhanced Dissolution ◽  
Carbonate Solutions ◽  
The Mean ◽  
Recoil Atoms ◽  
Fading Time ◽  
Complete Annealing

AbstractUsing natural ThO2 and UO2 in which radiation damage has accumulated over geologic periods, we have measured the relative in dissolution rates bicarbonate-carbonate solutions of the actinide isotopes 238U, 234U, 232Th, 230Th, and 228Th. An enhanced dissolution by a factor of 2 to 7 of the short lived (1.9 yr) 228Th relative to that of its structurally incorporated primary isotope 232Th indicates the presence of severe localized atomic displacement damage created by alpha-recoil atoms. In contrast, the relatively small (<20%) isotopic fractionation between the radiogenic 8.0 × 104 yr- 230Th isotope and 232Th, and between the radiogenic 2.5 × 105 yr- 234U isotope and its primary structurally incorporated isotope 238U, suggests the nearly complete annealing of the alpha-recoil damage during a period of less than 105 yr. An estimate of the mean fading time for the leachable damage is 15,000 yr.

MAXIMUM SECONDARY ELECTRON YIELDS FROM SEMICONDUCTORS AND INSULATORS

2016 ◽  
Vol 24 (04) ◽  
pp. 1750045 ◽  
Author(s):  
A. G. XIE ◽  
Z. H. LIU ◽  
Y. Q. XIA ◽  
M. M. ZHU
Keyword(s):  
Electron Emission ◽  
Secondary Electron ◽  
Maximum Yield ◽  
Secondary Electron Emission ◽  
High Energy ◽  
Secondary Electrons ◽  
Backscattered Electrons ◽  
Universal Formula ◽  
Yield Formula ◽  
Primary Electrons

Based on the processes and characteristics of secondary electron emission and the formula for the yield due to primary electrons hitting on semiconductors and insulators, the universal formula for maximum yield [Formula: see text] due to primary electrons hitting on semiconductors and insulators was deduced, where [Formula: see text] is the maximum ratio of the number of secondary electrons produced by primary electrons to the number of primary electrons. On the basis of the formulae for primary range in different energy ranges of [Formula: see text], characteristics of secondary electron emission and the deduced universal formula for [Formula: see text], the formulae for [Formula: see text] in different energy ranges of [Formula: see text] were deduced, where [Formula: see text] is the primary incident energy at which secondary electron yields from semiconductors and insulators, [Formula: see text], are maximized to maximum secondary electron yields from semiconductors and insulators, [Formula: see text]; and [Formula: see text] is the maximum ratio of the number of total secondary electrons produced by primary electrons and backscattered electrons to the number of primary electrons. According to the deduced formulae for [Formula: see text], the relationship among [Formula: see text], [Formula: see text] and high-energy back-scattering coefficient [Formula: see text], the formulae for parameters of [Formula: see text] and the experimental data as well as the formulae for [Formula: see text] in different energy ranges of [Formula: see text] as a function of [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] were deduced, where [Formula: see text] and [Formula: see text] are the original electron affinity and the width of forbidden band, respectively. The scattering of [Formula: see text] was analyzed, and calculated [Formula: see text] values were compared with the values measured experimentally. It was concluded that the deduced formulae for [Formula: see text] were found to be universal for [Formula: see text].

Radiation damage to charge coupled devices in the space environment

2002 ◽  
Author(s):  
A. Yamashita ◽  
T. Dotani ◽  
M. Bautz ◽  
G. Crew ◽  
H. Ezuka ◽  
...  
Keyword(s):  
Radiation Damage ◽  
Space Environment ◽  
Charge Coupled Devices

Space Tourism and Commercial Deep Space

2021 ◽  
pp. 281-290
Author(s):  
Dennis Meyer Bushnell
Keyword(s):  
Physical Space ◽  
Space Environment ◽  
Deep Space ◽  
Safety Issues ◽  
Space Tourism ◽  
Commercial Space ◽  
Private Citizens ◽  
Virtual Presence ◽  
Manned Space ◽  
Further Development

After some 60 years of highly trained astronauts going into space, the related technologies and costs have altered to the point where increasing numbers of private citizens can become space tourists, initially suborbital for minimal times and Earth orbital for up to the order of two weeks. There has also developed a rapidly improving digital reality/immersive virtual presence technology providing space tourism experiences at minimal cost and available essentially to everyone. The safety aspects of physical space tourism need further development, but those that relate to the space environment are tolerable for a few weeks from the 60 years of manned space flight experience. As space tourism over the years expands beyond earth orbit to moon, Mars, asteroids, other planets, etc., the safety issues will need to be seriously worked. Tourism is only a portion of what will become major opportunities and expansion of commercial space beyond earth utilities into deep space, enabled by the ongoing major reductions in the costs of space access.

The Energy Spectra of Secondary Electrons

2000 ◽  
Vol 6 (S2) ◽  
pp. 750-751
Author(s):  
David C Joy ◽  
David Braski
Keyword(s):  
Surface Layer ◽  
Electron Microscope ◽  
Secondary Electron ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Energy Spectra ◽  
Yield Coefficient ◽  
Sem Images ◽  
Secondary Electrons ◽  
Scanning Electron

It has been estimated that more than 90% of all scanning electron microscope (SEM) images ever published have been obtained using secondary electrons (SE) which are defined as being those electrons emitted with energies between 0 and 50eV. The properties of these secondary electron are therefore of considerable interest and importance. However, although secondary electrons have been intensively studied since their discovery by Starke in 1901 the majority of the work has been aimed at determining the SE yield coefficient and its variation with energy for elements and compounds. The energy spectrum of secondary electrons has received far less attention although it is evident that the form of the spectrum must have an effect on the image contrast observed in the SEM because SE detectors are energy selective devices. The few studies that have been made have mostly concentrated on spectra obtained from clean samples observed under ultra-high vacuum conditions. This is understandable, because it is certain that the presence of a surface layer of contamination will change the SE spectrum to some degree or other, but it is unfortunate because all specimens in real SEMs are dirty and it is information about this situation that is required.

scholarly journals Reconstruction of Pressureless Sintered Micron Silver Joints and Simulation Analysis of Elasticity Degradation in Deep Space Environment

2020 ◽  
Vol 10 (18) ◽  
pp. 6368
Author(s):  
Wendi Guo ◽  
Guicui Fu ◽  
Bo Wan ◽  
Ming Zhu
Keyword(s):  
Microstructural Evolution ◽  
Mechanical Response ◽  
Simulation Analysis ◽  
Three Dimensional ◽  
Effective Elastic Modulus ◽  
Space Environment ◽  
Analytical Models ◽  
Deep Space ◽  
Sem Images ◽  
Element Analysis

With excellent economy and properties, pressureless sintered micron silver has been regarded as an environmentally friendly interconnection material. In order to promote its reliable application in deep space exploration considering the porous microstructural evolution and its effect on macroscopic performance, simulation analysis based on the reconstruction of pressureless sintered micron silver joints was carried out. In this paper, the deep space environment was achieved by a test of 250 extreme thermal shocks of −170 °C~125 °C, and the microstructural evolution was observed by using SEM. Taking advantage of the morphology autocorrelation function, three-dimensional models of the random-distribution medium consistent with SEM images were reconstructed, and utilized in further Finite Element Analysis (FEA) of material effective elastic modulus through a transfer procedure. Compared with test results and two analytical models, the good consistency of the prediction results proves that the proposed method is reliable. Through analyzing the change in autocorrelation functions, the microstructural evolution with increasing shocks was quantitively characterized. Mechanical response characteristics in FEA were discussed. Moreover, the elasticity degradation was noticed and the mechanism in this special environment was clarified.

Two contributions to the ratio of the mean secondary electron generation of backscattered electrons to primary electrons at high electron energy

2014 ◽  
Vol 28 (06) ◽  
pp. 1450046 ◽  
Author(s):  
Ai-Gen Xie ◽  
Chen-Yi Zhang ◽  
Kun Zhong
Keyword(s):  
Atomic Number ◽  
Secondary Electron ◽  
High Energy ◽  
Primary Electron ◽  
Experimental Results ◽  
High Electron ◽  
Secondary Electrons ◽  
Backscattered Electrons ◽  
The Mean ◽  
Primary Electrons

Based on the main physical processes of secondary electron emission, experimental results and the characteristics of backscattered electrons (BE), the formula was derived for describing the ratio (β angle ) of the number of secondary electrons excited by the larger average angle of emission BE to the number of secondary electrons excited by the primary electrons of normal incidence. This ratio was compared to the similar ratio β obtained in the case of high energy primary electrons. According to the derived formula for β angle and the two reasons why β > 1, the formula describing the ratio β energy of β to β angle , reflecting the effect that the mean energy of the BE W AV p0 is smaller than the energy of the primary electrons at the surface, was derived. β angle and β energy computed using the experimental results and the deduced formulae for β angle and β energy were analyzed. It is concluded that β angle is not dependent on atomic number z, and that β energy decreases slowly with z. On the basis of the two reasons why β > 1, the definitions of β and β energy and the number of secondary electrons released per primary electron, the formula for β E-energy (the estimated β energy ) was deduced. The β E-energy computed using W AV p0, energy exponent and the formula for β E-energy is in a good agreement with β energy computed using the experimental results and the deduced formula for β energy . Finally, it is concluded that the deduced formulae for β angle and β energy can be used to estimate β angle and β energy , and that the factor that W AV p0 increases slowly with atomic number z leads to the results that β energy decreases slowly with z and β decreases slowly with z.

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