scholarly journals Charge asymmetry in electron/positron energy loss in nuclear Bremsstrahlung

2021 ◽  
Vol 2021 (12) ◽  
Author(s):  
Roman N. Lee ◽  
Andrey F. Pikelner
Keyword(s):  
Differential Equations ◽  
Energy Loss ◽  
Charge Asymmetry ◽  
High Energy ◽  
Coulomb Correction ◽  
Positron Energy ◽  
Incoming Particle ◽  
Electron Positron ◽  
The Difference ◽  
Arbitrary Energy

Abstract We calculate the leading Coulomb correction to the Bremsstrahlung energy loss in the electron-nucleus collisions for arbitrary energy of the incoming particle. This correction determines the charge asymmetry, i.e., the difference of electron and positron energy loss. The result is presented in terms of the classical polylogarithms Li2 and Li3. We use modern multiloop methods based on the IBP reduction and on the differential equations for master integrals. We provide both the threshold and the high-energy asymptotics of the found asymmetry and compare them with the available results.

scholarly journals The nature of the penetrating component of cosmic rays

1938 ◽  
Vol 165 (920) ◽  
pp. 11-31 ◽  
Author(s):  
Patrick Maynard Stuart Blackett
Keyword(s):  
Energy Loss ◽  
Average Energy ◽  
Great Majority ◽  
Cosmic Ray ◽  
High Energy ◽  
Transition Curve ◽  
Metal Plates ◽  
The Difference ◽  
Normal Electron ◽  
Transition Curves

The measurements by Neddermeyer and Anderson (1937) of the absorp­tion of cosmic-ray particles of low energy by metal plates differ in certain respects from those by Blackett and Wilson (1937). The former results showed that, in the energy range 1∙2 x 10 8 to 5 x 10 8 e-volts, two types of particles exist, an absorbable group assumed to behave as theory predicts of electrons and a much more penetrating group, attributed provisionally to heavier particles. On the other hand, we found that all the rays with energy under 2 x 10 8 e-volts were absorbed like electrons, while for rays of greater energy the average energy loss was very much less. Though a very few energetic particles were found to have a high energy loss, insufficient evidence was then available to justify classifying them as of a nature distinct from the less absorbable rays. Thus we obtained definite experimental evidence that the energy loss of the great majority of the rays varies rapidly with their energy. We concluded, therefore, that the energy loss of a normal electron varies with its energy. We now believe this to be probably false, since the success of the cascade theory of showers, in explaining the transition curve in the atmosphere, and a large part, at any rate, of the phenomena of the transition curves of showers and bursts, has provided fairly strong evidence that there must be a very few energetic rays at sea-level, which have the full radiation loss of electrons, even in heavy elements. It follows that the great majority of the rays, for which the energy loss certainly varies rapidly with energy, are probably not normal electrons. We therefore agree with the view of Neddermeyer and Anderson that it is likely that there are two types of particles present, though the difference in behaviour only exists for energies over 2 x 10 8 e-volts.

Monte Carlo Modelling of Secondary Electron Yield from Rough Surfaces

1990 ◽  
Vol 48 (1) ◽  
pp. 422-423
Author(s):  
John C. Russ
Keyword(s):  
Monte Carlo ◽  
Energy Loss ◽  
Secondary Electron ◽  
Secondary Electron Emission ◽  
Analytical Calculation ◽  
Mean Free Path ◽  
Single Scattering ◽  
High Energy ◽  
Secondary Electron Yield ◽  
Electron Yield

Monte-Carlo programs are well recognized for their ability to model electron beam interactions with samples, and to incorporate boundary conditions such as compositional or surface variations which are difficult to handle analytically. This success has been especially powerful for modelling X-ray emission and the backscattering of high energy electrons. Secondary electron emission has proven to be somewhat more difficult, since the diffusion of the generated secondaries to the surface is strongly geometry dependent, and requires analytical calculations as well as material parameters. Modelling of secondary electron yield within a Monte-Carlo framework has been done using multiple scattering programs, but is not readily adapted to the moderately complex geometries associated with samples such as microelectronic devices, etc.This paper reports results using a different approach in which simplifying assumptions are made to permit direct and easy estimation of the secondary electron signal from samples of arbitrary complexity. The single-scattering program which performs the basic Monte-Carlo simulation (and is also used for backscattered electron and EBIC simulation) allows multiple regions to be defined within the sample, each with boundaries formed by a polygon of any number of sides. Each region may be given any elemental composition in atomic percent. In addition to the regions comprising the primary structure of the sample, a series of thin regions are defined along the surface(s) in which the total energy loss of the primary electrons is summed. This energy loss is assumed to be proportional to the generated secondary electron signal which would be emitted from the sample. The only adjustable variable is the thickness of the region, which plays the same role as the mean free path of the secondary electrons in an analytical calculation. This is treated as an empirical factor, similar in many respects to the λ and ε parameters in the Joy model.

scholarly journals Resonant Effect of High-Energy Electron–Positron Pairs Production in Collision of Ultrarelativistic Electrons with an X-ray Electromagnetic Wave

Universe ◽  
2021 ◽  
Vol 7 (7) ◽  
pp. 210
Author(s):  
Georgii K. Sizykh ◽  
Sergei P. Roshchupkin ◽  
Victor V. Dubov
Keyword(s):  
High Energy ◽  
Energy Electron ◽  
Opening Angle ◽  
High Energy Electron ◽  
Scattered Electron ◽  
Differential Probability ◽  
X Ray ◽  
Electron Positron ◽  
Pulsar Radiation ◽  
Resonant Effect

The process of resonant high-energy electron–positron pairs production by electrons in an X-ray pulsar electromagnetic field is studied theoretically. Under the resonance conditions, the second-order process under consideration effectively reduces into two sequential first-order processes: X-ray-stimulated Compton effect and X-ray–stimulated Breit–Wheeler process. The kinematics of the process is studied in detail: the dependencies of the energy of the scattered electron on its outgoing angle and the energies of the particles of the pair on the outgoing angle of the scattered electron and the opening angle of the pair are obtained. The analysis of the number of different possible particles energies values in the entire range of the angles is also carried out, according to which the energies of the particles of the pair can take up to eight different values at a fixed outgoing angle of the scattered electron and opening angle of the pair. The estimate of the resonant differential probability per unit time of the process, which reaches the maximum value of 24 orders of the value of the non-resonant differential probability per unit time, is obtained. The angular distribution of the differential probability per unit time of the process is analyzed, particularly for the case of high-energy positrons presenting in pulsar radiation.

EXEELFS (Extended Electron Energy Loss Fine Structure) Study of Tin Grown by the DC Sputtering Technique.

2000 ◽  
Vol 6 (S2) ◽  
pp. 226-227
Author(s):  
Duarte-Moller A. ◽  
F. Espinosa-Maganña ◽  
R. Martínez-S´anchez ◽  
O. Contreras
Keyword(s):  
Energy Loss ◽  
Direct Current ◽  
Physical Vapor Deposition ◽  
Standard Procedure ◽  
High Energy ◽  
Structure Study ◽  
Voltage Source ◽  
Titanium Target ◽  
High Voltage Source ◽  
Mechanical Pump

Titanium nitride coatings were grown in a physical vapor deposition system assisted by a direct current reactive magnetron sputtering technique. The vacuum chamber was evacuated with a mechanical pump and cryopump to a base pressure of 10-7 Torr. The Sputtering was performed with a direct current high voltage source (0-1 Kev and 1 A) on a titanium target (99.98% purity). The titanium target was sputtered with a high purity argon -nitrogen mixture. The films were deposited on monocrystalline silicon (mc-Si) (111) substrates at different nitrogen partial pressures from 0.08 mTorr to 1.5 mTorr. Total pressure, power applied to target and substrate temperature were keep constant in all the experiments.EXEELFS analysis were done using the standard procedure [1,2]. In this case, we are find that the atomic concentration is in good agreement with the respective established stoichioinetry N/T=0.99. Figure 1 shows the window of high energy loss where appears their respective N K-edge and Ti -L23.

Correlation Between the V-I Characteristics of (0001) 4H-SiC PN Junctions Having Different Structural Features and Synchrotron X-ray Topography

2008 ◽  
Vol 1069 ◽  
Author(s):  
Ryoji Kosugi ◽  
Toyokazu Sakata ◽  
Yuuki Sakuma ◽  
Tsutomu Yatsuo ◽  
Hirofumi Matsuhata ◽  
...  
Keyword(s):  
High Energy ◽  
Structural Features ◽  
Incidence Geometry ◽  
Voltage Source ◽  
Large Area ◽  
Chip Area ◽  
Power Mosfets ◽  
X Ray ◽  
Pn Junctions ◽  
The Difference

ABSTRACTIn practical use of the SiC power MOSFETs, further reduction of the channel resistance, high stability under harsh environments, and also, high product yield of large area devices are indispensable. Pn diodes with large chip area have been already reported with high fabrication yield, however, there is few reports in terms of the power MOSFETs. To clarify the difference between the simple pn diodes and power MOSFETs, we have fabricated four pn-type junction TEGs having the different structural features. Those pn junctions are close to the similar structure of DIMOS (Double-implanted MOS) step-by-step from the simple pn diodes. We have surveyed the V-I characteristics dependence on each structural features over the 2inch wafer. Before their fabrication, we formed grid patterns with numbering over the 2inch wafer, then performed the synchrotron x-ray topography observation. This enables the direct comparison the electrical and spectrographic characteristics of each pn junctions with the fingerprints of defects.Four structural features from TypeA to TypeD are as follows. TypeA is the most simple structure as same as the standard pn diodes formed by Al+ ion implantation (I/I), except that the Al+ I/I condition conforms to that of the p-well I/I in the DIMOS. The JTE structure was used for the edge termination on all junctions. While the TypeA consists of one p-type region, TypeB and TypeC consists of a lot of p-wells. The difference of Type B and C is a difference of the oxide between the adjacent p-wells. The oxide of TypeB consists of the thick field oxide, while that of TypeC consists of the thermal oxide corresponding to the gate oxide in the DIMOS. In the TypeD structure, n+ region corresponding to the source in the DIMOS was added by the P+ I/I. The TypeD is the same structure of the DIMOS, except that the gate and source contacts are shorted. The V-I measurements of the pn junctions are performed using the KEITHLEY 237 voltage source meters with semi-auto probe machine. An active area of the fabricated pn junctions TEGs are 150um2 and 1mm2. Concentration and thickness of the drift layer are 1e16cm−3 and 10um, respectively.In order to compare the V-I characteristics of fabricated pn junctions with their defects information that obtained from x-ray topography measurements directly, the grid patterns are formed before the fabrication. The grid patterns were formed over the 2inch wafer by the SiC etching. The synchrotron x-ray topography measurements are carried out at the Beam-Line 15C in Photon-Factory in High-Energy-Accelerator-Research-Organization. Three diffraction conditions, g=11-28, -1-128, and 1-108, are chosen in grazing-incidence geometry (improved Berg-Barrett method).In the presentation, the V-I characteristics mapping on the 2inch wafer for each pn junctions, and the comparison of V-I characteristics with x-ray topography will be reported.

scholarly journals Overheating In Silicon During Pulsed-Laser Irradiation?

1985 ◽  
Vol 51 ◽  
Author(s):  
B. C. Larson ◽  
J. Z. Tischler ◽  
D. M. Mills
Keyword(s):  
Laser Irradiation ◽  
Thermal Strain ◽  
Pulsed Laser ◽  
Interface Velocity ◽  
High Energy ◽  
Time Resolved ◽  
Synchrotron Source ◽  
Zero Velocity ◽  
The Difference ◽  
Pulsed Laser Irradiation

ABSTRACTNanosecond resolution time-resolved x-ray diffraction measurements of thermal strain have been used to measure the interface temperatures in silicon during pulsed-laser irradiation. The pulsed-time-structure of the Cornell High Energy Synchrotron Source (CHESS) was used to measure the temperature of the liquid-solid interface of <111> silicon during melting with an interface velocity of 11 m/s, at a time of near zero velocity, and at a regrowth velocity of 6 m/s. The results of these measurements indicate 110 K difference between the temperature of the interface during melting and regrowth, and the measurement at zero velocity shows that most of the difference is associated with undercooling during the regrowth phase.

scholarly journals Towards Sustainable Development: Building’s Retrofitting with PCMs to Enhance the Indoor Thermal Comfort in Tropical Climate, Malaysia

2021 ◽  
Vol 13 (7) ◽  
pp. 3614
Author(s):  
Zeyad Amin Al-Absi ◽  
Mohd Isa Mohd Hafizal ◽  
Mazran Ismail ◽  
Azhar Ghazali
Keyword(s):  
Climate Change ◽  
Sustainable Development ◽  
Thermal Comfort ◽  
Phase Change Materials ◽  
Thermal Environment ◽  
High Energy ◽  
Transition Temperatures ◽  
Indoor Thermal Environment ◽  
Adaptive Thermal Comfort ◽  
The Difference

Building sector is associated with high energy consumption and greenhouse gas emissions, which contribute to climate change. Sustainable development emphasizes any actions to reduce climate change and its effect. In Malaysia, half of the energy utilized in buildings goes towards building cooling. Thermal comfort studies and adaptive thermal comfort models reflect the high comfort temperatures for Malaysians in naturally conditioned buildings, which make it possible to tackle the difference between buildings’ indoor temperature and the required comfort temperature by using proper passive measures. This study investigates the effectiveness of building’s retrofitting with phase change materials (PCMs) as a passive cooling technology to improve the indoor thermal environment for more comfortable conditions. PCM sheets were numerically investigated below the internal finishing of the walls. The investigation involved an optimization study for the PCMs transition temperatures and quantities. The results showed significant improvement in the indoor thermal environment, especially when using lower transition temperatures and higher quantities of PCMs. Therefore, the monthly thermal discomfort time has decreased completely, while the thermal comfort time has increased to as high as 98%. The PCM was effective year-round and the optimum performance for the investigated conditions was achieved when using 18mm layer of PCM27-26.

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