scholarly journals The β-particle emission of radium D

1931 ◽  
Vol 133 (822) ◽  
pp. 367-380 ◽  
Keyword(s):  
Energy Distribution ◽  
Distribution Curve ◽  
Continuous Distribution ◽  
Absolute Number ◽  
Particle Emission ◽  
Low Energy ◽  
Secondary Particles ◽  
Energy Distribution Curve ◽  
Γ Ray ◽  
Number Of Particles

The main object of this investigation was to obtain an energy distribution curve for the electrons emitted by radium D during its disintegration. Such a distribution curve may be expected to be made up by the electrons coming from the nucleus, which have a continuous distribution of energy, together with secondary particles forming groups of homogeneous energy, produced by the action of the single γ-ray of radium D. The nuclear electrons are of great interest because owing to their very low energy they have never been identified with any certainty. The energy distribution finally obtained is shown in fig. 4, each point on the curve representing the number of particles having energies lying within 1000 volts on either side of the point. A secondary object of the work was to attempt to estimate the absolute number of particles emitted per disintegration, which number should, of course, be unity for the nuclear particles and some fraction less than unity for the secondary groups. The latter are due to the ejection of electrons from the L and outer atomic levels only, since the energy of the γ-ray, 47,200 volts, is insufficient to ionise the K level.

Quantitative Auger and XPS Analysis of Thin Films

MRS Bulletin ◽  
1992 ◽  
Vol 17 (12) ◽  
pp. 39-45 ◽  
Author(s):  
J.M. Slaughter ◽  
W. Weber ◽  
Gernot Güntherodt ◽  
Charles M. Falco
Keyword(s):  
Thin Films ◽  
Energy Distribution ◽  
Photoelectron Spectroscopy ◽  
Distribution Curve ◽  
High Surface ◽  
Peak Height ◽  
Auger Electrons ◽  
X Ray ◽  
Surface Sensitivity ◽  
Energy Distribution Curve

In 1925, P. Auger first observed the so-called Auger electrons in a Wilson cloud chamber. He explained this occurrence as being due to a radiationless transition in atoms excited by a primary x-ray photon source. In 1953, Lander first pointed out that Auger electrons arising from solid samples can be detected in the energy distribution curve of secondary electrons from surfaces subjected to electron bombardment. Moreover, low-energy Auger electrons (∼1 keV kinetic energy) can escape from only the first several atomic layers of a surface since they are strongly absorbed by even a monolayer of atoms. Thus Auger electron spectroscopy (AES) possesses high surface sensitivity. This is one characteristic that makes AES very useful for the study of thin films. For such applications, an important development in AES occurred when Harris showed that the sensitivity of the detection of Auger electrons can be improved by differentiating the electron energy distribution curve with respect to the energy. Furthermore, Weber and Johnson demonstrated that, provided the Auger line profile does not change, the peak-to-peak height in the differentiated energy distribution curves is proportional to the Auger current in the peak. Therefore, in addition to its surface sensitivity, AES also can be used for quantitative studies of thin films.Like AES, x-ray photoelectron spectroscopy (XPS) is a surface-sensitive technique that uses the energy distribution of electrons ejected from a thin film for quantitative analysis. However, in many ways the information provided by AES and XPS is complementary.

QUASIPARTICLES IN HIGH-TEMPERATURE SUPERCONDUCTORS

2003 ◽  
Vol 17 (04n06) ◽  
pp. 578-583
Author(s):  
ROBERTA CITRO ◽  
MARIA MARINARO ◽  
K. NAKAGAWA
Keyword(s):  
High Temperature ◽  
Energy Distribution ◽  
Hubbard Model ◽  
Spectral Function ◽  
Momentum Distribution ◽  
Distribution Curve ◽  
High Temperature Superconductors ◽  
Quantum Criticality ◽  
Energy Distribution Curve ◽  
Coupling Approach

We study the quantum criticality effects induced by a singular charge vertex on the quasiparticle spectral function of an extended single-band Hubbard model. It is shown that the spectral intensity computed in a strong-coupling approach, reproduces the Momentum Distribution Curve (MDC) and the Energy Distribution Curve (EDC) of ARPES experiments on Bi 2 Sr 2 CaCu 2 O 8+δ.

The miso low energy γ-ray telescope

1979 ◽  
Vol 158 ◽  
pp. 595-604 ◽  
Author(s):  
R.E. Baker ◽  
R.C. Butler ◽  
A.J. Dean ◽  
G. Di Cocco ◽  
N.A. Dipper ◽  
...  
Keyword(s):  
Low Energy ◽  
Γ Ray

scholarly journals The colorimetric properties of the spectrum

1931 ◽  
Vol 108 (759) ◽  
pp. 576-576 ◽  
Keyword(s):  
Distribution Curve ◽  
National Physical Laboratory ◽  
Group Of Seven ◽  
Physical Laboratory ◽  
Luminosity Functions ◽  
Direct Measurements ◽  
Energy Distribution Curve ◽  
The Mean ◽  
General Method

The paper describes an investigation carried out at the National Physical Laboratory to determine the colorimetric properties of a group of seven subjects as obtained from direct measurements of the trichromatic coefficients of the spectrum on a trichromatic colorimeter. The “spectral distribution curves of the primaries,” by means of which the colorimetric quality of a heterochromatic stimulus may be computed from its energy distribution curve, are obtained by combining the experimentally determined trichromatic coefficients with the International Standard visibility curve. This procedure is a simplification, applicable to the mean results of a normal group, of a general method by which the chromatic and luminosity functions of any subject or group of subjects can be determined from one set of observations. The general method is described in an Appendix.

scholarly journals Broad-band study of high-synchrotron-peaked BL Lac object 1ES 1218+304

2020 ◽  
Vol 496 (4) ◽  
pp. 5518-5527
Author(s):  
N Sahakyan
Keyword(s):  
Energy Distribution ◽  
Electron Energy ◽  
Power Law ◽  
Spectral Energy Distribution ◽  
Broad Band ◽  
Energy Distributions ◽  
X Ray ◽  
Bl Lac ◽  
Photon Index ◽  
Γ Ray

ABSTRACT The origin of the multiwavelength emission from the high-synchrotron-peaked BL Lac 1ES 1218+304 is studied using the data from SwiftUVOT/XRT, NuSTAR, and Fermi-LAT. A detailed temporal and spectral analysis of the data observed during 2008–2020 in the  γ-ray (>100 MeV), X-ray (0.3–70 keV), and optical/UV bands is performed. The γ-ray spectrum is hard with a photon index of 1.71 ± 0.02 above 100 MeV. The SwiftUVOT/XRT data show a flux increase in the UV/optical and X-ray bands; the highest 0.3–3 keV X-ray flux was (1.13 ± 0.02) × 10−10 erg cm−2 s−1. In the 0.3–10 keV range, the averaged X-ray photon index is >2.0 which softens to 2.56 ± 0.028 in the 3–50 keV band. However, in some periods, the X-ray photon index became extremely hard (<1.8), indicating that the peak of the synchrotron component was above 1 keV, and so 1ES 1218+304 behaved like an extreme synchrotron BL Lac. The hardest X-ray photon index of 1ES 1218+304 was 1.60 ± 0.05 on MJD 58489. The time-averaged multiwavelength spectral energy distribution is modelled within a one-zone synchrotron self-Compton leptonic model using a broken power law and power law with an exponential cutoff electron energy distributions. The data are well explained when the electron energy distribution is $E_{\rm e}^{-2.1}$ extending up to γbr/cut ≃ (1.7 − 4.3) × 105, and the magnetic field is weak (B ∼ 1.5 × 10−2 G). By solving the kinetic equation for electron evolution in the emitting region, the obtained electron energy distributions are discussed considering particle injection, cooling, and escape.

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