A REVIEW OF PARTICLE-INDUCED X-RAY EMISSION IN GEOLOGY

1991 ◽  
Vol 01 (04) ◽  
pp. 311-338 ◽  
Author(s):  
J. D. MACARTHUR ◽  
XIN-PEI MA
Keyword(s):  
Gamma Rays ◽  
Gamma Ray ◽  
Light Element ◽  
X Rays ◽  
Geological Samples ◽  
Geological Material ◽  
Element Analysis ◽  
X Ray ◽  
Gamma Ray Emission

Particle-induced X-ray emission is very well suited for the analysis of geological samples. This review discusses the characteristics for such analyses. For light-element analysis, the complimentary technique of particle-induced gamma ray emission is also discussed since the emission of gamma rays occurs simultaneously with the X-rays. Not only are exploratory investigations of PIXE's capabilities presented but also synopses of studies aimed at answering geological questions. The latter have become more and more common in the last few years, an indication of PIXE's maturity as a technique for clement analysis of geological material.

The neutron, gamma-ray, X-ray spectrometer (NGXS): A compact instrument for making combined measurements of neutrons, gamma-rays, and X-rays

2014 ◽  
Vol 93 ◽  
pp. 524-529 ◽  
Author(s):  
David J. Lawrence ◽  
William C. Feldman ◽  
Robert E. Gold ◽  
John O. Goldsten ◽  
Ralph L. McNutt
Keyword(s):  
Gamma Rays ◽  
Gamma Ray ◽  
X Rays ◽  
X Ray ◽  
Combined Measurements

scholarly journals The Flare of 1989 September 9, 09:09 UT: Does Coronal Loop Collision Initiate Efficient Gamma-Ray Emission?

1994 ◽  
Vol 142 ◽  
pp. 707-711
Author(s):  
H. Aurass ◽  
A. Hofmann ◽  
E. Rieger
Keyword(s):  
Current Sheet ◽  
Gamma Rays ◽  
Coronal Loop ◽  
Gamma Ray ◽  
High Energy ◽  
X Rays ◽  
Subject Headings ◽  
Γ Ray ◽  
Gamma Ray Emission ◽  
Magnetogram Data

AbstractVector magnetogram data and Hα pictures together with data published by Chupp et al. lead us to conjecture that in the presented case a contact between the rising two-ribbon flare current sheet and a coronal loop connecting two nearby plage regions initiates efficient high-energy γ-ray emission.Subject headings: Sun: corona — Sun: flares — Sun: X-rays, gamma rays

Light Element Analysis

1969 ◽  
Vol 13 ◽  
pp. 26-48
Author(s):  
A. K. Baird
Keyword(s):  
Atomic Number ◽  
Matrix Effects ◽  
Light Element ◽  
Electron Excitation ◽  
Electron Gun ◽  
X Rays ◽  
Element Analysis ◽  
X Ray ◽  
High Emission ◽  
Quantitative Analyses

Qualitative and quantitative analyses of elements below atomic number 20, and extending to atomic number 4, have been made practical and reasonably routine only in the past five to ten years by advances in: 1) excitation sources; 2) dispersive spectrometers; 3) detection devices; and 4) reductions of optic path absorption. At present agreement is lacking on the best combination of parameters for light element analysis. The principal contrasts in opinion concern excitation.Direct electron excitation, particularly as employed in microprobe analysis (but not limited to such instruments), provides relatively high emission intensities of all soft X-rays, but also generates a high continuum, requires the sample to be at essentially electron gun vacuum, and introduces practical calibration problems (“matrix effects“). X-ray excitation of soft X-rays overcomes some of the latter three disadvantages, and has its own limitations. Sealed X-ray sources of conventional or semi-conventional design can provide useful (if not optimum) light element emission intensities down to atomic number 9, hut with serious loss of efficiency in many applications below atomic number 15 largely because of window-thinness limitations under electron bombardment.

scholarly journals Gamma-rays from SS433: evidence for periodicity

2019 ◽  
Vol 485 (2) ◽  
pp. 2970-2975 ◽  
Author(s):  
Kajwan Rasul ◽  
Paula M Chadwick ◽  
Jamie A Graham ◽  
Anthony M Brown
Keyword(s):  
Energy Range ◽  
Photon Energy ◽  
Gamma Rays ◽  
Gamma Ray ◽  
Temporal Analysis ◽  
Photon Energy Range ◽  
X Ray ◽  
Relativistic Jet ◽  
Gamma Ray Emission

ABSTRACT In this paper we present our study of the gamma-ray emission from the microquasar SS433. Integrating over 9 yr of Fermi-LAT Pass 8 data, we detect SS433 with a significance of ∼13σ in the 200 to 500 MeV photon energy range, with evidence for an extension in the direction of the w1 X-ray ‘hotspot’. A temporal analysis reveals evidence for modulation of SS433’s gamma-ray emission with the precession period of its relativistic jet. This suggests that at least some of SS433’s gamma-ray emission originates close to the object rather than from the jet termination regions.

scholarly journals Centaurus A at Hard X-Rays and Soft Gamma-Rays

2010 ◽  
Vol 27 (4) ◽  
pp. 431-438 ◽  
Author(s):  
H. Steinle
Keyword(s):  
Energy Range ◽  
Spatial Resolution ◽  
Gamma Rays ◽  
Gamma Ray ◽  
Spectral Energy Distribution ◽  
High Energy ◽  
Spectral Energy ◽  
X Rays ◽  
Satellite Mission ◽  
X Ray

AbstractCen A, at a distance of less than 4 Mpc, is the nearest radio-loud AGN. Its emission is detected from radio to very-high energy gamma-rays. Despite the fact that Cen A is one of the best studied extragalactic objects the origin of its hard X-ray and soft gamma-ray emission (100 keV <E< 50 MeV) is still uncertain. Observations with high spatial resolution in the adjacent soft X-ray and hard gamma-ray regimes suggest that several distinct components such as a Seyfert-like nucleus, relativistic jets, and even luminous X-ray binaries within Cen A may contribute to the total emission in the MeV regime that has been detected with low spatial resolution. As the Spectral Energy Distribution of Cen A has its second maximum around 1 MeV, this energy range plays an important role in modeling the emission of (this) AGN. As there will be no satellite mission in the near future that will cover this energies with higher spatial resolution and better sensitivity, an overview of all existing hard X-ray and soft gamma-ray measurements of Cen A is presented here defining the present knowledge on Cen A in the MeV energy range.

Effect of X-ray Tube Window Thickness on Detection Limits for Light Elements in XRF Analysis

1994 ◽  
Vol 38 ◽  
pp. 299-305
Author(s):  
Daniel J. Whalen ◽  
D. Clark Turner
Keyword(s):  
Light Element ◽  
Detection Limits ◽  
X Rays ◽  
Light Elements ◽  
Absorption Data ◽  
Element Analysis ◽  
X Ray ◽  
Data Compilation ◽  
Beryllium Window ◽  
X Ray Background

Abstract Widespread interest in light element analysis using XRF has stimulated the development of thin x-ray tube windows. Thinner windows enhance the soft x-ray output of the tube, which more efficiently excite the light elements in the sample. A computer program that calculates the effect of window thickness on light element sample fluorescence has been developed. The code uses an NIST algorithm to calculate the x-ray tube spectrum given various tube parameters such as beryllium window thickness, operating voyage, anode composition, and take-off angle. The interaction of the tube radiation with the sample matrix is modelled to provide the primary and secondary fluorescence from the sample. For x-rays in the energy region 30 - 1000 eV the mass attenuation coefficients were interpolated from the photo absorption data compilation of Henke, et al. The code also calculates the x-ray background due to coherent and incoherent scatter from the sample, as well as the contribution of such scatter to the sample fluorescence. Given the sample fluorescence and background the effect of tube window thickness on detection limits for light elements can be predicted.

scholarly journals The Bright Optical Flash and Afterglow from the Gamma-Ray Burst GRB 130427A

Science ◽  
2013 ◽  
Vol 343 (6166) ◽  
pp. 38-41 ◽  
Author(s):  
W. T. Vestrand ◽  
J. A. Wren ◽  
A. Panaitescu ◽  
P. R. Wozniak ◽  
H. Davis ◽  
...  
Keyword(s):  
Gamma Rays ◽  
Gamma Ray ◽  
Massive Stars ◽  
Close Correlation ◽  
Optical Observations ◽  
X Rays ◽  
Reverse Shock ◽  
Gamma Ray Burst ◽  
Forward Shock ◽  
Gamma Ray Emission

The optical light generated simultaneously with x-rays and gamma rays during a gamma-ray burst (GRB) provides clues about the nature of the explosions that occur as massive stars collapse. We report on the bright optical flash and fading afterglow from powerful burst GRB 130427A. The optical and >100–megaelectron volt (MeV) gamma-ray flux show a close correlation during the first 7000 seconds, which is best explained by reverse shock emission cogenerated in the relativistic burst ejecta as it collides with surrounding material. At later times, optical observations show the emergence of emission generated by a forward shock traversing the circumburst environment. The link between optical afterglow and >100-MeV emission suggests that nearby early peaked afterglows will be the best candidates for studying gamma-ray emission at energies ranging from gigaelectron volts to teraelectron volts.

scholarly journals Hot Accretion Disks and the High Energy Background

1983 ◽  
Vol 104 ◽  
pp. 345-346
Author(s):  
M. Kafatos ◽  
Jean A. Eilek
Keyword(s):  
Active Galactic Nuclei ◽  
Accretion Disks ◽  
Spectral Range ◽  
Gamma Rays ◽  
Gamma Ray ◽  
Galactic Nuclei ◽  
Seyfert Galaxies ◽  
High Energy ◽  
X Rays ◽  
X Ray

The origin of the high energy (X-ray and gamma-ray) background may be attributed to discrete sources, which are usually thought to be active galactic nuclei (AGN) (cf. Rothschild et al. 1982, Bignami et al. 1979). At X-rays a lot of information has been obtained with HEAO-1 in the spectral range 2–165 keV. At gamma-rays the background has been estimated from the Apollo 15 and 16 (Trombka et al. 1977) and SAS-2 (Bignami et al. 1979) observations. A summary of some of the observations (Rothschild et al. 1982) is shown in Figure 1. The contribution of AGN to the diffuse high energy background is uncertain at X-rays although it is generally estimated to be in the 20–30% range (Rothschild et al. 1982). At gamma-rays, in the range 1–150 MeV, AGN (specifically Seyfert galaxies) could account for all the emission.

scholarly journals Gamma-Ray Spectral Observations with Yohkoh

1994 ◽  
Vol 142 ◽  
pp. 639-643 ◽  
Author(s):  
M. Yoshimori ◽  
K. Suga ◽  
K. Morimoto ◽  
T. Hiraoka ◽  
J. Sato ◽  
...  
Keyword(s):  
Gamma Rays ◽  
Gamma Ray ◽  
Temporal Evolution ◽  
Spectral Feature ◽  
Line Emission ◽  
Flux Ratio ◽  
X Rays ◽  
X Ray ◽  
Angle Scattering ◽  
Positron Production

AbstractWe present gamma-ray observations of the 1991 October 27, November 15, and December 3 flares with the Yohkoh gamma-ray and hard X-ray spectrometers. The October 27 flare (X6.1 /3B) shows significant gamma-ray line emission, and the temporal evolution of the gamma-ray line-to-bremsstrahlung flux ratio indicates that protons and electrons were complicatedly accelerated during flare. The December 3 flare (X2.0/2B) shows a strong bremsstrahlung continuum extending to 10 MeV and indicates that electrons were preferentially accelerated to 10 MeV. A line feature at 420 keV was observed from the November 15 flare (X1.0/3B). This is most likely due to a compound of redshifted nuclear deexcitation lines of Be (429 keV) and Li (478 keV) resulting from He-He reactions. The spectral feature indicates that the accelerated He nuclei suffer strong pitch-angle scattering in the corona and form a downward-peaked distribution. Furthermore, the November 15 flare exhibits evidence of positron annihilation line at 511 keV. The positron production processes and the electron density of the annihilation region are discussed on the basis of the temporal characteristics of 511 keV line emission.Subject headings: line: identification — Sun: flares — Sun: X-rays, gamma-rays

Sign in / Sign up

Export Citation Format

Share Document