scholarly journals MECHANISM OF BIJUNCTION SEMICONDUCTOR DEVICE DAMAGE INDUCED BY HEAVY PARTICLES

2015 ◽  
Vol 78 (2-2) ◽  
Author(s):  
Saafie Salleh ◽  
Fuei Pien Chee ◽  
Haider F. Abdul Amir
Keyword(s):  
Semiconductor Device ◽  
High Energy ◽  
Electronic Systems ◽  
Heavy Particles ◽  
Energetic Ions ◽  
Bipolar Junction Transistor ◽  
Energy Gamma ◽  
Junction Transistor ◽  
Γ Rays ◽  
Physical Phenomena

The physical phenomena associated with the stopping of energetic ions in semiconductor materials have always been a subject which receives great theoretical and experimental interest. Consequently, bombardment of high energy particles and high energy gamma (γ) rays causes potential hazards to these electronic systems. These effects range from degradation of performance to functional failure that can affect the system operations. Such upsets becoming increasingly likely as electronic components are getting more sophisticated while decreasing in size and moves to larger integration. In this paper, the penetration of gamma rays, utilizing Cobalt-60 (Co-60)) into bipolar junction transistor (BJT) is being simulated using the program simulation SRIM. From the findings, it is observed that the penetration of Co-60 ions into the simulated BJT leads to production of lattice defects in the form of vacancies, defect clusters and dislocations. These can alter the material parameters and hence the functional properties of the devices.

Evaluation on Diffusion of Bipolar Junction Transistor (BJT) Charge-Carrier and its Dependency on Total Dose Irradiation

2013 ◽  
Vol 701 ◽  
pp. 71-76 ◽  
Author(s):  
Haider F. Abdul Amir ◽  
Fuei Pien Chee
Keyword(s):  
Ionizing Radiation ◽  
Total Dose ◽  
Electronic Device ◽  
Outer Space ◽  
High Energy ◽  
Bipolar Junction Transistor ◽  
Excited Atoms ◽  
Radiation Induced ◽  
Junction Transistor ◽  
Γ Rays

Electronic device that subjected to various effects by radiations can cause small interferences such as noises in the circuit. These effects are especially critical in operating environment such as outer space, where radiation comes in stronger and more frequent. In this research, analytical study on the effects of ionizing radiation induced by 60Co gamma (γ) rays in bipolar junction transistor (BJT) devices had been performed. It was found that the high energy of the radiation allows more valence electrons to be excited to the conduction band in the BJT. This leads to the production of a large number of excited atoms and increases the holes in the valence band. The increase of holes in the base region due to trapping will increase the probability of recombination and reducing the number of electrons that reaches the collector region. This ionizing radiation effect was found to arouse either a permanent or temporarily damage in the devices depending on their current drives and total dose absorbed.

scholarly journals Very high energy gamma-rays from flat spectrum radio quasars

2014 ◽  
Vol 10 (S313) ◽  
pp. 27-32
Author(s):  
Elina Lindfors
Keyword(s):  
Gamma Rays ◽  
Gamma Ray ◽  
High Energy ◽  
High Energy Gamma ◽  
Spectrum Radio ◽  
Very High Energy ◽  
Energy Gamma ◽  
Emission Models ◽  
Γ Rays ◽  
Very High

AbstractThe detection of Flat Spectrum Radio Quasars (FSRQs) in the Very High Energy (VHE, E>100 GeV) range is challenging, mainly because of their steep soft spectra and distance. Nevertheless four FSRQs are now known to be VHE emitters. The detection of the VHE γ-rays has challenged the emission models of these sources. The sources are also found to exhibit very different behavior. I will give an overview of what is known about the VHE emission of these sources and about the multiwavelength signatures that are connected to the VHE gamma-ray emission.

scholarly journals Phenomena associated with the anomalous absorption of high energy gamma radiation.—II

1934 ◽  
Vol 143 (850) ◽  
pp. 681-706 ◽  
Keyword(s):  
Gamma Radiation ◽  
Scattered Radiation ◽  
Wave Length ◽  
Large Angle ◽  
High Energy ◽  
Secondary Radiation ◽  
Anomalous Absorption ◽  
Small Thickness ◽  
Energy Gamma ◽  
Γ Rays

In a previous paper we gave an account of an investigation of the secondary radiation produced when different elements are irradiated with the high energy γ-rays of thorium C". The present paper describes an extension of this investigation. It will be reduced that confusion with the ordinary scattered radiation was almost entirely eliminated by examining the secondary radiation in a direction making a large angle with the primary beam, since under these conditions not only is the Compton radiation relatively very much weaker, but in addition it is comparatively soft and is easily absorbed in the radiator itself, or in a very small thickness of absorber, owing to the large increase in wave-length at this large angle of scattering.

scholarly journals Centaurus A: Hard X-ray and High-Energy Gamma-Ray Light Curve Correlation

Galaxies ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 44 ◽  
Author(s):  
Isak Davids ◽  
Markus Böttcher ◽  
Michael Backes
Keyword(s):  
Light Curve ◽  
High Energy ◽  
Electromagnetic Spectrum ◽  
X Rays ◽  
X Ray ◽  
Correlation Studies ◽  
High Energy Gamma ◽  
Energy Gamma ◽  
Γ Rays ◽  
Centaurus A

Centaurus A, powered by a 55 million solar mass supermassive black hole, has been intensively monitored in all accessible wavelength ranges of the electromagnetic spectrum. However, its very-high energy gamma ( γ ) ray flux (TeV photons), obtained from H.E.S.S. is relatively faint, hampering detailed light curve analyses in the most energetic energy band. Yet, the extensive long-term light curve data from Fermi-LAT and Swift-BAT (hard X-rays) allows for cross-correlation studies. We find a hint that X-ray emission from Centaurus A precedes the γ rays by 25 ± 125 days. If this lag is real and related to a γ γ absorption effect in the broad-line region (BLR) around the central source, we can constrain the size of the BLR using light-travel time arguments. These are first results of extended light curve correlation studies between high-energy γ rays and X-rays from Centaurus A.

VERY HIGH ENERGY GAMMA-RAY MEASUREMENTS OF BLAZARS

2008 ◽  
Vol 17 (09) ◽  
pp. 1431-1441
Author(s):  
BERRIE GIEBELS
Keyword(s):  
Black Hole ◽  
Gamma Ray ◽  
High Energy ◽  
The Status ◽  
Relativistic Flow ◽  
Very High Energy ◽  
Acceleration Zone ◽  
Energy Gamma ◽  
Γ Rays ◽  
Very High

The origin of γ-rays emitted by blazars is widely attributed to radiative cooling of the most energetic particles in a relativistic flow, which itself is thought to originate from the surroundings of a supermassive black hole. The linkage between the accreting gas, the black hole, jet formation, and the observed radiation from the jet, are still very difficult to establish. The most energetic γ-rays are likely to be produced close to the comptonizing particles acceleration zone, and are therefore a unique probe of the underlying physical mechanisms at play. This report contains a review of the status of the field of Very High Energy (VHE) γ-ray astronomy, in the light of measurements from the current generation of Atmospheric Čerenkov Telescopes (ACTs), which have dramatically changed our view of blazars over the last years, and given us new insights about the blazar phenomenon.

scholarly journals Detection of very-high-energy gamma-ray transients with monitoring facilities

2020 ◽  
Vol 497 (3) ◽  
pp. 3142-3148
Author(s):  
G La Mura ◽  
G Chiaro ◽  
R Conceição ◽  
A De Angelis ◽  
M Pimenta ◽  
...  
Keyword(s):  
Gamma Ray ◽  
High Energy ◽  
Field Of View ◽  
Telescope Array ◽  
Monitoring Strategies ◽  
Very High Energy ◽  
Energy Gamma ◽  
Γ Rays ◽  
Near Future ◽  
Very High

ABSTRACT The observation of very-high-energy γ-rays (VHE γ-rays, $E \gt 100\,$ GeV) has ledto the identification of extremely energetic processes and particle-acceleration sites both within our Galaxy and beyond. It is expected that VHE facilities, such as the Cherenkov Telescope Array, will explore these sources with an unprecedented level of detail. However, the transient and unpredictable nature of many important processes means that their observation requires the development of proper monitoring strategies. In this study, we estimate the properties of VHE transients that can be effectively detected by monitoring facilities. We use data collected by the Fermi-LAT instrument during its monitoring campaign to select events that are probably associated with VHE emission. We use this sample to estimate the frequency, the luminosity and the time-scales of various transients, focusing on blazar flares and gamma-ray bursts. We discuss how the balance between the field of view, sensitivity and duty cycle of an observatory affects the likelihood of detecting transients that occur at the inferred rates, and we conclude by describing the contribution that current and near-future monitoring facilities can make to the identification and study of VHE transient emission.

ULTRA HIGH ENERGY GAMMA RAY OBSERVATION BY SPACE-BASED EXPERIMENTS

2005 ◽  
Vol 20 (29) ◽  
pp. 7020-7022 ◽  
Author(s):  
NAOTO SAKAKI
Keyword(s):  
Geomagnetic Field ◽  
Gamma Ray ◽  
High Energy ◽  
Ultra High Energy ◽  
Top Down ◽  
High Energy Cosmic Rays ◽  
Shower Development ◽  
Unique Method ◽  
Energy Gamma ◽  
Γ Rays

If Ultra-high energy cosmic rays (UHECRs) with E > 1020 eV are produced by a top down model, most of them are expected to be γ-rays. When a UHE gamma ray comes almost parallel to the geomagnetic field, it does not suffer geomagnetic cascade and its air shower development is suppressed by the Landau-Pomeranchuk-Migdal (LPM) effect. In order to investigate UHECRs of the top down origin, the correlation of "LPM hole" and the geomagnetic field observed by a space-based experiment may be a unique method to detect UHE γ-rays.

scholarly journals Study of Galaxy Evolution Using VHE γ-ray Observations with Ground-based Čerenkov Telescopes

2001 ◽  
Vol 204 ◽  
pp. 151-151
Author(s):  
A. Konopelko
Keyword(s):  
Galaxy Evolution ◽  
Gamma Ray ◽  
Spectral Energy Distribution ◽  
High Energy ◽  
Spectral Energy ◽  
Extragalactic Background Light ◽  
The Galaxy ◽  
Energy Gamma ◽  
Γ Rays ◽  
Luminosity Evolution

The spectral distribution of the extragalactic background light (EBL) in the infrared yields important information about the evolution of galaxies. The spectrum of a galaxy in the 0.1–200 μm region is a footprint of the intrinsic starlight at ~ 1μm and its extinction by dust with re-emission at ~ 100 μm. The overall spectral energy distribution of the EBL is then determined by the galaxy luminosity evolution. High-energy γ-rays are absorbed by the EBL photons through γγ → e+e- reactions. Such an effect has been seen recently in the Mkn 501 TeV spectrum measured by the HEGRA (High Energy Gamma Ray Astronomy) collaboration using an advanced system of imaging atmospheric Čerenkov telescopes (IACTs). The intrinsic spectra of AGNs in the 50 GeV-1 TeV energy range may be constrained by the X-ray fluxes measured with satellite instruments aboard missions such as RXTE, XMM, and ASCA. By reducing the energy threshold down to 50 GeV, forthcoming ground-based IACTs systems (CANGAROO IV, H.E.S.S., VERITAS) may be able to study the absorption cutoff in energy spectra of distant AGNs (z< 0.4), to unfold the true galaxy luminosity evolution function.

scholarly journals High Energy Gamma Rays from Accretion Disc

1981 ◽  
Vol 94 ◽  
pp. 335-336
Author(s):  
F. Giovannelli ◽  
S. Karakula ◽  
W. Tkaczyk
Keyword(s):  
Black Hole ◽  
Gamma Rays ◽  
Gamma Quantum ◽  
High Energy ◽  
Accretion Disc ◽  
Inelastic Collisions ◽  
Production Spectrum ◽  
Hot Plasma ◽  
Energy Gamma ◽  
Γ Rays

In the case of spherical symmetric accretion into a black hole, the matter may be heated up to the temperature KT = 0.1 mpc2 (Kolykhalov and Sunyaev, 1979). In such a hot plasma inelastic collisions of protons may produce Π° which is the gamma quantum source.In this work we determined γ-rays production spectrum in the comoving plasma reference frame, expected γ-rays spectrum for the case of spherica symmetric accretion of matter into a black hole and the upper limit to the number of black holes in Galaxy is evaluated.

scholarly journals Observations of High-energy Gamma-ray Bursts with EGRET

1995 ◽  
Vol 151 ◽  
pp. 358-362
Author(s):  
M. Merck ◽  
D.L. Bertsch ◽  
B.L. Dingus ◽  
C.E. Fichtel ◽  
R.C. Hartman ◽  
...  
Keyword(s):  
Neutron Stars ◽  
Gamma Ray ◽  
Cosmic Strings ◽  
High Energy ◽  
Gamma Ray Bursts ◽  
Published Data ◽  
High Energy Gamma ◽  
Transient Source ◽  
Energy Gamma ◽  
Γ Rays

Gamma Ray Bursts (GRBs) have puzzled astronomers since their discovery more than 20 years ago. As no counterparts at wavelengths other than X- and γ-rays have yet been found the identification of the sources is still missing. Theoretical explanations range from colliding comets (1993) and merging neutron stars (1982) to more exotic objects, such as superconducting cosmic strings (1988). Data accumulated until now still do not discriminate between these models, although results from the BATSE (Burst and Transient Source Experiment) instrument aboard the Compton Gamma Ray Observatory (CGRO) strongly favor extragalactic models.The Energetic Gamma Ray Experiment Telescope (EGRET) aboard CGRO has s ofar detected photons from 5 GRBs with its spark chamber. These are the highest energy γ-rays associated with GRBs to date. In this work we review previously published data and summarize the properties of these events. Elsewhere we present possible constraints from the data on the models proposed to explain GRBs.

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