Low-energy cosmic X-ray measurements

1969 ◽  
Vol 47 (23) ◽  
pp. 2651-2666 ◽  
Author(s):  
A. J. Baxter ◽  
B. G. Wilson ◽  
D. W. Green
Keyword(s):  
Spectral Analysis ◽  
Energy Range ◽  
Crab Nebula ◽  
Spectral Characteristics ◽  
Low Energy ◽  
Data Recovery ◽  
X Rays ◽  
X Ray ◽  
Recovery System ◽  
The Crab Nebula

An experiment is described to investigate cosmic X rays in the energy range 0.25–12 keV. The data-recovery system and methods of spectral analysis are considered. Results are presented for the energy spectrum of the diffuse X-ray component and its distribution over the northern sky down to 1.6 keV with a limited extension at 0.27 keV.In the energy range 1.6 to 12 keV, the spectrum is represented by:[Formula: see text]although separate analyses indicate a flattening below 4.5 keV to give:[Formula: see text]and[Formula: see text]At the lowest energies, the flux appears to increase more rapidly and exhibits some anisotropy in arrival directions related to the gross galactic structure. Spectral characteristics of the Crab Nebula and Cygnus X-2 have also been determined.

Low-energy Bremsstrahlung X-ray spectra from a stable auroral arc

1969 ◽  
Vol 47 (21) ◽  
pp. 2427-2430 ◽  
Author(s):  
B. G. Wilson ◽  
A. J. Baxter ◽  
D. W. Green
Keyword(s):  
Energy Range ◽  
Power Law ◽  
Spectral Characteristics ◽  
Low Energy ◽  
X Rays ◽  
X Ray ◽  
Rocket Experiment

During a rocket experiment launched to investigate cosmic X rays, the directional features and spectral characteristics of X rays from an auroral arc have been determined in the 1.6 to 10 keV energy range. The spectrum was best represented by a power law of slope −3.365 ± 0.07.

Sky survey of high-energy cosmic X-rays and spectral information on sources in the Crab nebula, Cygnus, and Scorpius

1968 ◽  
Vol 46 (10) ◽  
pp. S409-S413 ◽  
Author(s):  
Walter H. G. Lewin ◽  
George W. Clark ◽  
William B. Smith
Keyword(s):  
Crab Nebula ◽  
High Energy ◽  
X Rays ◽  
Coma Cluster ◽  
X Ray ◽  
Sky Survey ◽  
Upper Limits ◽  
Intensity Ratios ◽  
The Crab Nebula ◽  
Made In

A complete X-ray survey of the northern sky has been made in the energy range 20–100 keV. Spectra are given for Cyg X-1 and Tau X-1. Intensity ratios (Cyg X-1/Tau X-1) of 0.84 ± 0.10 and 1.30 ± 0.25 were derived in the 20–70 keV range from data obtained on July 19, 1966 and February 13, 1967, respectively. Observations on Sco X-1 and the Coma cluster show upper limits which are quite different from results reported by other groups.

scholarly journals Interstellar Absorption of the Low Energy X-rays from the Crab Nebula

1973 ◽  
Vol 165 (4) ◽  
pp. 355-361 ◽  
Author(s):  
P. A. Charles ◽  
J. L. Culhane ◽  
I. R. Tuohy
Keyword(s):  
Crab Nebula ◽  
Low Energy ◽  
X Rays ◽  
Interstellar Absorption ◽  
The Crab Nebula

A Pinhole Camera for Photographing X-Rays from Laser-Produced Plasmas*

1974 ◽  
Vol 18 ◽  
pp. 136-145
Author(s):  
J. J. Hohlfelder ◽  
M. A. Palmer
Keyword(s):  
Energy Range ◽  
Spatial Resolution ◽  
Spatial Information ◽  
Laser System ◽  
Pulsed Laser ◽  
Pinhole Camera ◽  
Low Energy ◽  
X Rays ◽  
X Ray ◽  
Laboratory Calibration

AbstractA pinhole camera has been used to record low-energy x rays produced from CD2 microsphere irradiation with Sandia Laboratories four-beam, pulsed laser system. Camera useful energy range, spatial resolution, and x-ray energy sensitivity are discussed. Camera x-ray energy sensitivity which was determined by laboratory calibration is compared with measurements obtained with a multi-channel x-ray spectrometer. X-ray photographs of laser-irradiated microspheres are presented. Spatial information about the x-ray source derived from these photographs is discussed.

Low Energy Mass Absorption Coefficients from Proton Induced X-ray Spectroscopy

1976 ◽  
Vol 20 ◽  
pp. 481-486 ◽  
Author(s):  
A. Lurio ◽  
W. Reuter ◽  
J. Keller
Keyword(s):  
Energy Range ◽  
Experimental Technique ◽  
Low Energy ◽  
X Rays ◽  
Proton Bombardment ◽  
Absorption Coefficients ◽  
X Ray ◽  
Mass Absorption

We describe a new and reliable experimental technique for the measurement of mass absorption coefficients in the 0.1 to 1 keV energy range. In this technique, the absorbing film is supported directly on a substrate which under proton bombardment will generate the x-rays whose absorption will be measured. Results are given for thirteen different metals at the C Kα (277 eV) line.

scholarly journals Development of low-energy X-ray detectors using LGAD sensors

2019 ◽  
Vol 26 (4) ◽  
pp. 1226-1237 ◽  
Author(s):  
Marie Andrä ◽  
Jiaguo Zhang ◽  
Anna Bergamaschi ◽  
Rebecca Barten ◽  
Camelia Borca ◽  
...  
Keyword(s):  
Energy Range ◽  
Single Photon ◽  
Signal To Noise Ratio ◽  
Photon Counting ◽  
Low Energy ◽  
X Rays ◽  
Single Photon Counting ◽  
X Ray ◽  
Internal Gain ◽  
Silicon Sensors

Recent advances in segmented low-gain avalanche detectors (LGADs) make them promising for the position-sensitive detection of low-energy X-ray photons thanks to their internal gain. LGAD microstrip sensors fabricated by Fondazione Bruno Kessler have been investigated using X-rays with both charge-integrating and single-photon-counting readout chips developed at the Paul Scherrer Institut. In this work it is shown that the charge multiplication occurring in the sensor allows the detection of X-rays with improved signal-to-noise ratio in comparison with standard silicon sensors. The application in the tender X-ray energy range is demonstrated by the detection of the sulfur K α and K β lines (2.3 and 2.46 keV) in an energy-dispersive fluorescence spectrometer at the Swiss Light Source. Although further improvements in the segmentation and in the quantum efficiency at low energy are still necessary, this work paves the way for the development of single-photon-counting detectors in the soft X-ray energy range.

X-ray flux from discrete sources

1970 ◽  
Vol 37 ◽  
pp. 88-93
Author(s):  
U. R. Rao ◽  
E. V. Chitnis ◽  
A. S. Prakasarao ◽  
U. B. Jayanthi
Keyword(s):  
Energy Spectrum ◽  
Energy Range ◽  
Low Energy ◽  
X Rays ◽  
X Ray ◽  
Preliminary Results ◽  
Absolute Flux ◽  
The Absolute

Preliminary results of two rocket flights carrying X-ray payloads conducted from Thumba Equatorial Rocket Launching Station (TERLS), Trivandrum, India, on November 3, 1968, and November 7, 1968, respectively, are presented. The results indicate the first evidence for the existence of low energy X-ray flux in the energy range 2–20 keV from Cen-X2 source since the reported extinction in May, 1967. The energy spectrum and the absolute flux of X-rays from Cen-X2, Sco-X1 and Tau-X1 are presented and compared with other observations.

scholarly journals X-Radiation from Supernova Remnants

1973 ◽  
Vol 55 ◽  
pp. 105-117
Author(s):  
K. A. Pounds
Keyword(s):  
Supernova Remnants ◽  
Crab Nebula ◽  
Low Energy ◽  
Radiation Mechanism ◽  
X Ray ◽  
The Crab Nebula

Available X-ray observations of supernova remnants are reviewed. The number of SNR seen above 2 keV remains small after inclusion of the UHURU results and for only the Crab Nebula is the data adequate to clearly indicate the radiation mechanism. The increasing importance of low energy X-ray studies (below 1 keV) of older and relatively nearby remnants is noted. Brief discussion is given of the relation of the X-ray data to current ideas of the evolution of SNR.

scholarly journals Synchrotron Radiation in High Magnetic Fields

1971 ◽  
Vol 46 ◽  
pp. 314-320
Author(s):  
D. F. Falla ◽  
A. Evans
Keyword(s):  
Synchrotron Radiation ◽  
Magnetic Fields ◽  
Gamma Ray ◽  
Radiation Power ◽  
Crab Nebula ◽  
Low Energy ◽  
High Magnetic Fields ◽  
X Ray ◽  
The Crab Nebula ◽  
Fundamental Mechanism

We suggest that if there exist within the Crab Nebula localised condensations of material containing high magnetic fields, (≫ 1 G), the rapidly evolving synchrotron radiation power spectrum emitted by a single electron can give a radiation continuum with a spectral index having a unique value similar to that observed in the optical and low-energy X-ray regions. One implication of this result is that a simple comparison between the observed fluxes of optical and gamma radiation emitted by the Nebula is no longer meaningful, so that one cannot draw any immediate conclusion regarding the fundamental mechanism of electron and gamma ray production.

scholarly journals Calibration and measurement of X-ray personal dose equivalent with a Hp(10) ionization chamber

2021 ◽  
pp. 19-19
Author(s):  
Yang Xu ◽  
Rui Zhao
Keyword(s):  
Energy Range ◽  
Ionization Chamber ◽  
Conversion Coefficient ◽  
Low Energy ◽  
X Rays ◽  
Correction Factors ◽  
Dose Equivalent ◽  
X Ray ◽  
Conversion Coefficients ◽  
Small Change

The value of personal dose equivalent at10 mm depth is to characterize the energy deposition of strong penetrating radiation in human body and is derived by measurement of air kerma and application of conversion coefficients from ISO report. However, the conversion coefficients depend strongly on the photon energy and angles of incidence for low-energy photons. In order to overcome the problem that the conversion coefficient of low energy rays changes greatly due to the small change of energy, a secondary standard ionization chamber was used to measure personal dose equivalent directly. A matched reference field was established with (20-250) kV X-rays and correction factors with Hp(10) chamber were calculated under these radiation qualities with different angles of incidence. The results showed that the differences were almost 22.7 % of correction factors for the low energy photons at angles of incidence 0?. With conversion coefficient recommended in ISO 4037-3-2019, performance of the chamber response with respect to Hp(10) in the energy range from 33 keV to 208 keV was within about ?10%, and in the energy range from 12 keV to 208 keV and for angles of incidence between 0? and 75? was within about ?19%.

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