scholarly journals Emission of γ rays by x-ray electron-nuclear transitions

1997 ◽  
Vol 56 (1) ◽  
pp. 381-387 ◽  
Author(s):  
Silviu Olariu ◽  
Agata Olariu ◽  
Valeriu Zoran
Keyword(s):  
X Ray ◽  
Nuclear Transitions ◽  
Γ Rays

scholarly journals The internal conversion of gamma-rays.—Part II

1928 ◽  
Vol 121 (787) ◽  
pp. 447-456
Keyword(s):  
Magnetic Field ◽  
Quantum Mechanics ◽  
Wave Equation ◽  
Gamma Rays ◽  
Internal Conversion ◽  
Scalar Potential ◽  
X Ray ◽  
Electro Magnetic Field ◽  
Γ Rays ◽  
Electro Magnetic

In a previous paper the absorption of γ-rays in the K-X-ray levels of the atom in which they are emitted was calculated according to the Quantum Mechanics, supposing the γ-rays to be emitted from a doublet of moment f ( t ) at the centre of the atom. The non-relativity wave equation derived from the relativity wave equation for an electron of charge — ε moving in an electro-magnetic field of vector potential K and scalar potential V is h 2 ∇ 2 ϕ + 2μ ( ih ∂/∂ t + εV + ih ε/μ c (K. grad)) ϕ = 0. (1) Suppose, however, that K involves the space co-ordinates. Then, (K. grad) ϕ ≠ (grad . K) ϕ , and the expression (K . grad) ϕ is not Hermitic. Equation (1) cannot therefore be the correct non-relativity wave equation for a single electron in an electron agnetic field, and we must substitute h 2 ∇ 2 ϕ + 2μ ( ih ∂/∂ t + εV) ϕ + ih ε/ c ((K. grad) ϕ + (grad. K) ϕ ) = 0. (2)

scholarly journals Evaluation the Safety and Security Procedures used In X-ray Clinics in Al-Harthiya-Baghdad

2021 ◽  
Vol 2114 (1) ◽  
pp. 012009
Author(s):  
Thuraya A. Abdul Hussian ◽  
Anwar kh. Farman
Keyword(s):  
Ionizing Radiation ◽  
X Rays ◽  
X Ray ◽  
Beta Particles ◽  
Medical Clinics ◽  
Γ Rays ◽  
Health Laws ◽  
Different Sources ◽  
Α Particles ◽  
Security Procedures

Abstract Radiation is a form of energy, its emitted either in the form of particles such as α-particles and β-particles (beta particles including the electron and the positron) or waves such as sunlight, X-rays and γ-rays. Radiation found everywhere around us and it comes from many different sources naturally or man-made sources. In this study a questionnaire was distributed to people working in the field of X-rays that used for a medical imaging (X-ray and CT-scan) to evaluate the extent of awareness and knowledge in estimate the damage of ionizing radiation as a result of wrong use. The questionnaire was distributed to medical clinics in Al-Harithiya in Baghdad, which it’s considered as one of the important areas in Iraq to attract and treat patients. It’s found that most of the commitment of radiography clinics by safety and security procedures. Most of the radiology clinics abide by most of the Iraqi Ministry of Health laws. However, some clinics did not implement some of the security and safety conditions

scholarly journals Pair Production in AGN

1989 ◽  
Vol 134 ◽  
pp. 194-196
Author(s):  
C. Done ◽  
A. C. Fabian
Keyword(s):  
Pair Production ◽  
Compton Scattering ◽  
Energy Flux ◽  
Large Fraction ◽  
Small Region ◽  
X Rays ◽  
X Ray ◽  
Electron Positron ◽  
Γ Rays ◽  
Radiant Power

The X-ray luminosity and variability of many AGN are sufficiently extreme that any hard γ-rays produced in the source will collide with the X-rays and create electron-positron pairs, rather than escape. A small region where vast amounts of energy are produced, such as an AGN, is an ideal place to accelerate particles to relativistic energies and so produce γ-rays by Compton scattering. The observed X-ray spectra of AGN are hard and indicate that most of the luminosity is at the highest energies so that absorption of the γ-rays represents a large fraction of the energy flux, which can then be re-radiated at lower energies. Pairs can thus effectively reprocess much of the radiant power in an AGN.

scholarly journals Experiments to test whether the secondary γ-rays are polarised

1909 ◽  
Vol 83 (559) ◽  
pp. 40-49
Keyword(s):  
Magnetic Force ◽  
Maximum Force ◽  
X Rays ◽  
X Ray ◽  
Accelerated Motion ◽  
Straight Line ◽  
Γ Rays ◽  
Considerable Body

When an electron is given an accelerated motion along a straight line, a spherical pulse of electric and magnetic force is sent out, and the maximum force lies in a plane at right angles to the direction of acceleration. The want of symmetry in the distribution of the force with respect to the direction of acceleration of the electron gave rise to the term polarisation. Barkla has shown that the primary X-rays from an X-ray tube are partially polarised, that is to say, that the maximum radiation proceeds in a plane at right angles to the direction of propagation of the cathode rays. If the secondary X-rays are produced by electrons set in motion by the primary pulses we should expect that, under certain conditions, the secondary rays would also be polarised. This has also been shown to be the case by Barkla. Since there is a considerable body of evidence to show that X-rays and γ -rays are similar in kind, it was thought by the writer that it would be of importance to make some experiments in order to discover whether secondary γ -rays are polarised.

Decay properties of 181Ir

1978 ◽  
Vol 56 (3) ◽  
pp. 321-326 ◽  
Author(s):  
I. M. Ladenbauer-Bellis ◽  
P. Sen ◽  
H. Bakhru
Keyword(s):  
Half Life ◽  
Decay Scheme ◽  
Heavy Ion ◽  
Heavy Ion Reactions ◽  
X Ray ◽  
Decay Properties ◽  
Helium Jet ◽  
Γ Rays ◽  
Ge Detector ◽  
Γ Ray

181Ir activity was produced via the following heavy-ion reactions: 169Tm (16O,4n)181Ir and 169Tm(19F,7n)181Pt (51 s) decaying to 181Ir. The half-life of 181Ir was found to be 4.90 ± 0.15 min. Singles and coincidence γ-ray measurements were performed using 30–40 cm3 Ge(Li) detectors. X-Ray measurements were carried out using an intrinsic Ge-detector. Additionally the helium jet system was used to study the properties of this isotope. The following γ rays were found to belong to the decay of 181Ir: 19.6, 65.3, 93.8, 107.6, 117.9, 123.5, 184.6, 189.9, 227.0, 231.6, 239.2, 309.0, 318.9, 350.5, 352.8, 375.2, 576.5, 700.1, 871.2, 1182.3, 1192.6, 1347.1, 1381.0, 1528.8, 1545.0, 1565.6, 1593.4, 1639.6, 1646.4, 1652.5, and 1714.9 keV. A tentative decay scheme is proposed for 181Ir, verifying levels in l8lOs that have been obtained by reaction work. The proposed decay scheme as well as spin and parity assignments of some of the 181Os levels are discussed.

scholarly journals X-ray plateaus in gamma-ray bursts’ light curves from jets viewed slightly off-axis

2020 ◽  
Vol 492 (2) ◽  
pp. 2847-2857 ◽  
Author(s):  
Paz Beniamini ◽  
Raphaël Duque ◽  
Frédéric Daigne ◽  
Robert Mochkovitch
Keyword(s):  
Gamma Ray ◽  
Large Fraction ◽  
Gamma Ray Bursts ◽  
Point Of View ◽  
Light Curves ◽  
Late Time ◽  
X Ray ◽  
Narrow Region ◽  
Central Engine ◽  
Γ Rays

ABSTRACT Using multiple observational arguments, recent work has shown that cosmological gamma-ray bursts (GRBs) are typically viewed at angles within, or close to the cores of their relativistic jets. One of those arguments relied on the lack of tens-of-days-long periods of very shallow evolution that would be seen in the afterglow light curves of GRBs viewed at large angles. Motivated by these results, we consider that GRBs efficiently produce γ-rays only within a narrow region around the core. We show that, on these near-core lines of sight, structured jets naturally produce shallow phases in the X-ray afterglow of GRBs. These plateaus would be seen by a large fraction of observers and would last between 102–105 s. They naturally reproduce the observed distributions of time-scales and luminosities as well as the intercorrelations between plateau duration, plateau luminosity, and prompt γ-ray energy. An advantage of this interpretation is that it involves no late-time energy injection which would be both challenging from the point of view of the central engine and, as we show here, less natural given the observed correlations between plateau and prompt properties.

Young radio sources at high-energies and the γ-ray CSO PKS 1718–649

2018 ◽  
Vol 14 (S342) ◽  
pp. 176-179
Author(s):  
Giulia Migliori
Keyword(s):  
Radio Galaxy ◽  
Radio Galaxies ◽  
High Energy ◽  
Radio Sources ◽  
Host Galaxies ◽  
X Ray ◽  
High Energies ◽  
Γ Rays ◽  
Γ Ray ◽  
High Energy Emission

AbstractObservations at high-energies are important to define the first stages of the evolution of extragalactic radio sources and to characterize the interstellar medium of their host galaxies. In some of the X-ray-observed Compact Symmetric Objects (CSOs, among the youngest and most compact radio galaxies), we measured values of the total hydrogen column densities large enough to slow or prevent the radio source growth. The γ-ray window has the potential to constrain the non-thermal contribution of jets and lobes to the total high-energy emission. However, so far, young radio sources remain elusive in γ-rays, with only a handful of detections (or candidates) reported by Fermi. I present our γ-ray study of the CSO PKS 1718–649, and draw comparison with the restarted, γ-ray detected, radio galaxy 3C 84.

scholarly journals Crystal Structural, Morphological and Gamma Ray Shielding (γ-S) Efficiency of PVA/PAAm/PAA Polymer Blend Loaded With Silver Nanoparticles via Casting Method

2021 ◽  
Author(s):  
Karar Abdali
Keyword(s):  
Silver Nanoparticles ◽  
Gamma Ray ◽  
Petri Dish ◽  
X Ray Diffraction ◽  
Light Spectrum ◽  
Major Purpose ◽  
X Ray ◽  
Casting Technique ◽  
Ft Ir ◽  
Γ Rays

Abstract Cost, weightiness, vacuum, and absorption power of the matters applied for radiological preservation are significant points which challenge scientists and researchers to preparation and improve suitable γ-S materials. A perfect γ-S is one which can absorb, attenuate, or prevent the ultimate part of incident γ-radiation. The major purpose of this study is to evaluation the effect of silver nanoparticles (AgNPs) additions on the γ-S characteristics of polyvinyl alcohol PVA, polyacrylamide PAAm and polyacrylic acid PAA polymeric blend (PB). In the current research, PVA/PAAm/PAA (70:20:10) wt./wt.% matrix PB with 0, 0.03, 0.06 and 0.08 wt% of AgNPs were synthesized via Petri dish casting technique as a polymer nanocomposites (PNCs). The specimen were categorized as h0,h1,h2 and h3 depending on the addition of AgNPs. Crystal structure involves X-ray diffraction (X-ray), the Fourier transformation infrared spectrum (FT-IR), ultraviolet-visible light spectrum (UV-V) and optical microscopy (OPM) were studied. The coefficients of attenuation were also computed utilizing caesium (Cs137) source. Results showed which increasing of AgNPs from 0% to 0.08% leads to increasing in the attenuation coefficient values and decreasing the ratio of radiation counts (N/Nₒ), also 0.08% of AgNPs loaded is the essential optimum consist of this additive. The γ-S properties conducted using γ-rays has explained which PNCs with 8% of AgNPs and only 0.090 cm thickness, can attenuate 80% of the γ- ray.

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