scholarly journals Further experiments on the absorption and scattering of γ-rays

1925 ◽  
Vol 109 (749) ◽  
pp. 206-223 ◽  
Keyword(s):  
Direct Method ◽  
Wave Length ◽  
X Rays ◽  
Short Waves ◽  
General Law ◽  
Direct Measurements ◽  
Wide Range ◽  
Important Direction ◽  
Γ Rays ◽  
Effective Wave

The absorption and scattering of γ-rays by elements has already formed the subject of two papers published recently in these proceedings. The objects of the experiments described in this paper were (1) to extend the absorption measurements, especially in the more important direction of the extremely short waves emitted by RaC, and (2) to make a thorough investigation, with special reference to Compton’s theory, of the scattering by matter of these high-frequency radiations. It was shown in the papers referred to that the absorption of γ-rays from RaB + C, filtered through 1 cm. of lead, is closely expressed by relations similar to those which hold for X-rays. Estimates of the mean-effective wave-length of the beam placed the value at about 0.02 Å. U. Now, it is well known from the crystal analysis of Rutherford and Andrade, and the β-ray magnetic spectra measurements of Ellis, and Ellis, and Skinner, that the γ-rays emitted by radium products cover a wide range of wave-length —roughly, from 1.0 to 0.005 Å. U. It is, however, uncertain whether the very short waves obey the same general laws of absorption as the ordinary X-rays. Direct measurements on a few selected homogeneous rays, though capable of yielding most important results, are unfortunately impracticable. The problem has, therefore, been attacked by the less direct method of measuring accurately the absorption of a complex beam, successively hardened by means of five suitable filters. It will be shown that in every case the absorption of γ-rays obeys the same general law as has already been found. The measurements also throw some light on the spectral distribution of energy in the beam.

scholarly journals β-ray spectra and their meaning

1922 ◽  
Vol 101 (708) ◽  
pp. 1-17 ◽  
Keyword(s):  
Wave Length ◽  
X Rays ◽  
Ernest Rutherford ◽  
Active Atom ◽  
Magnetic Spectrum ◽  
Γ Rays

In a previous paper, I described some measurements of the magnetic spectrum of the β-ravs ejected from various metals by the γ-rays of radium B. These experiments showed that the conversion of monochromatic γ-rays into β-rays was described by the same quantum relation that holds for X-rays and light, and using this knowledge it was found possible to give a complete explanation of the natural β-ray spectrum of radium B. Sir Ernest Rutherford had already shown that the lines in the β-ray spectrum were due in some way to the conversion of monochromatic γ-rays in the same radio active atom that emitted them, and these experiments on the excited spectra now proved that the strong lines were due to the conversion of the γ-rays in the K ring, and the weaker lines to conversion in the L 3 ring. This explanation of the line β-ray spectrum is, by itself, of considerable interest, but of far greater importance is the fact that these experiments give a method of finding the wave-lengths of γ-rays. The shortest wave-length that has been measured by the crystal method is 0·07 Å. U., and at present it seems almost impossible to extend this range much further by this method. Since many radio-active bodies emit γ-rays of shorter wave-length than this any method by which these wave-lengths may be found is important

The Effective Wave-length of γ Rays

Nature ◽  
1925 ◽  
Vol 116 (2910) ◽  
pp. 206-207 ◽  
Author(s):  
D. SKOBELTZYN
Keyword(s):  
Wave Length ◽  
Γ Rays ◽  
Effective Wave

scholarly journals The absolute energies of the groups in magnetic β-ray spectra

1924 ◽  
Vol 105 (729) ◽  
pp. 60-69 ◽  
Keyword(s):  
Magnetic Field ◽  
Wave Length ◽  
X Rays ◽  
Homogeneous Groups ◽  
Absorption Energy ◽  
Length Measurements ◽  
Γ Rays ◽  
Γ Ray ◽  
The Absolute ◽  
The Difference

Most β-ray bodies emit several homogeneous groups of β-rays, and the energies of the electrons forming these groups may be found from the deflection they suffer in a magnetic field. Various experiments have shown that these groups are due to the conversion, according to the quantum relation, of γ-rays in the different electronic levels of the atom. In fact, the energy of any group is of the form E 1 = hv — (absorption energy of level). Two β-ray groups due to the conversion of a γ-ray of definite frequency in the K and L levels of the atom will differ in energy by the difference in energy between the K and L absorption energies. Both in testing this equation, and in using it to deduce frequencies of the γ-rays, it is necessary to compare energies of β-rays determined in terms of a magnetic field, with absorption energies deduced from wave-length measurements of X-rays. It is thus important to obtain values of the absolute β-ray energies as accurate as possible. The most accurate previous values were those of Rutherford and Robinson.

scholarly journals Low-Power, Subthreshold Reference Circuits for the Space Environment: Evaluated with γ-rays, X-rays, Protons and Heavy Ions

Electronics ◽  
2019 ◽  
Vol 8 (5) ◽  
pp. 562 ◽  
Author(s):  
Charalambos M. Andreou ◽  
Diego Miguel González-Castaño ◽  
Simone Gerardin ◽  
Marta Bagatin ◽  
Faustino Gómez Rodriguez ◽  
...  
Keyword(s):  
Integrated Circuits ◽  
Low Power ◽  
Heavy Ions ◽  
Cmos Technology ◽  
Space Environment ◽  
X Rays ◽  
Space Applications ◽  
Wide Range ◽  
Radiation Hardened ◽  
Γ Rays

The radiation tolerance of subthreshold reference circuits for space microelectronics is presented. The assessment is supported by measured results of total ionization dose and single event transient radiation-induced effects under γ -rays, X-rays, protons and heavy ions (silicon, krypton and xenon). A high total irradiation dose with different radiation sources was used to evaluate the proposed topologies for a wide range of applications operating in harsh environments similar to the space environment. The proposed custom designed integrated circuits (IC) circuits utilize only CMOS transistors, operating in the subthreshold regime, and poly-silicon resistors without using any external components such as compensation capacitors. The circuits are radiation hardened by design (RHBD) and they were fabricated using TowerJazz Semiconductor’s 0.18 μm standard CMOS technology. The proposed voltage references are shown to be suitable for high-precision and low-power space applications. It is demonstrated that radiation hardened microelectronics operating in subthreshold regime are promising candidates for significantly reducing the size and cost of space missions due to reduced energy requirements.

Evaluation of Soft and Hard Scarttered X-Rays as an Internal Standard for Light Element Analysis

1969 ◽  
Vol 13 ◽  
pp. 80-93
Author(s):  
David L. Taylor ◽  
George Andermann
Keyword(s):  
Matrix Effects ◽  
Wave Length ◽  
Internal Standard ◽  
Light Element ◽  
X Rays ◽  
Element Analysis ◽  
Scattering Angle ◽  
Wide Range ◽  
The Matrix ◽  
Internal Standardization

In the research described, the use of scattered x-rays has been successfully applied as an internal standard for the analysis of calcium in aqueous specimens containing a wide range of matrix components. In addition to the demonstration of the utility of scattered x-rays for light element analysis, some comments are offered on the fundamental aspects of this technique, since to date the method has not been explained thoroughly. The present research represents a continued effort to determine the fundamental importance of various parameters intrinsic to any collection of atoms undergoing scattering, such as the Rayleigh-Compton ratio, the scattering angle, the wave length utilized, and the presence or absence of discontinuities in the matrix absorption coefficient. It has been concluded that large values of the scattering angle coupled with short wavelength tend to yield improved internal compensation. The results also indicate that for light matrices the Compton component of the scattered continuum is of particular importance in achieving good internal standardization for matrix effects.

The Photoelectric Absorption of Gamma Rays

1931 ◽  
Vol 27 (1) ◽  
pp. 103-112 ◽  
Author(s):  
L. H. Gray
Keyword(s):  
Absorption Coefficient ◽  
Atomic Number ◽  
Gamma Rays ◽  
Wave Length ◽  
X Rays ◽  
Photoelectric Absorption ◽  
Empirical Law ◽  
Γ Rays ◽  
Image Position

No satisfactory formula has so far been derived theoretically for the photoelectric absorption of X-rays and γ-rays. The empirical lawhas hitherto been generally accepted as giving approximately the variation of the photoelectric absorption coefficient per electron, with atomic numberZand wave length λ for X-rays of wave length greater than 100 X.U., and the validity of this law has often been assumed for γ-rays also.

A Color Coded STEM/SEM Image Storage System

1981 ◽  
Vol 39 ◽  
pp. 272-273
Author(s):  
Y. Kokubo ◽  
W. H. Hardy ◽  
J. Dance ◽  
K. Jones
Keyword(s):  
Image Processing ◽  
Electron Beam ◽  
Storage System ◽  
Particle Analysis ◽  
Specific Information ◽  
X Rays ◽  
Sem Image ◽  
Backscattered Electrons ◽  
Wide Range ◽  
Scanning Electron

A color coded digital image processing is accomplished by using JEM100CX TEM SCAN and ORTEC’s LSI-11 computer based multi-channel analyzer (EEDS-II-System III) for image analysis and display. Color coding of the recorded image enables enhanced visualization of the image using mathematical techniques such as compression, gray scale expansion, gamma-processing, filtering, etc., without subjecting the sample to further electron beam irradiation once images have been stored in the memory.The powerful combination between a scanning electron microscope and computer is starting to be widely used 1) - 4) for the purpose of image processing and particle analysis. Especially, in scanning electron microscopy it is possible to get all information resulting from the interactions between the electron beam and specimen materials, by using different detectors for signals such as secondary electron, backscattered electrons, elastic scattered electrons, inelastic scattered electrons, un-scattered electrons, X-rays, etc., each of which contains specific information arising from their physical origin, study of a wide range of effects becomes possible.

Solvent-Ligand Interactions in Colloidal Nanocrystals

2018 ◽  
Author(s):  
Jonathan De Roo ◽  
Nuri Yazdani ◽  
Emile Drijvers ◽  
Alessandro Lauria ◽  
Jorick Maes ◽  
...  
Keyword(s):  
Direct Method ◽  
Line Broadening ◽  
H Nmr ◽  
Size Dependent ◽  
Line Shape Analysis ◽  
Wide Range ◽  
Nanocrystal Synthesis ◽  
Ligand Interactions ◽  
Indispensable Tool ◽  
Theoretical Evidence

<p>Although solvent-ligand interactions play a major role in nanocrystal synthesis, dispersion formulation and assembly, there is currently no direct method to study this. Here we examine the broadening of <sup>1</sup>H NMR resonances associated with bound ligands, and turn this poorly understood descriptor into a tool to assess solvent-ligand interactions. We show that the line broadening has both a homogeneous and a heterogeneous component. The former is nanocrystal-size dependent and the latter results from solvent-ligand interactions. Our model is supported by experimental and theoretical evidence that correlates broad NMR lines with poor ligand solvation. This correlation is found across a wide range of solvents, extending from water to hexane, for both hydrophobic and hydrophilic ligand types, and for a multitude of oxide, sulfide and selenide nanocrystals. Our findings thus put forward NMR line shape analysis as an indispensable tool to form, investigate and manipulate nanocolloids.</p>

scholarly journals β-Lactoglobulin Adsorption Layers at the Water/Air Surface: 5. Adsorption Isotherm and Equation of State Revisited, Impact of pH

2021 ◽  
Vol 5 (1) ◽  
pp. 14
Author(s):  
Georgi G. Gochev ◽  
Volodymyr I. Kovalchuk ◽  
Eugene V. Aksenenko ◽  
Valentin B. Fainerman ◽  
Reinhard Miller
Keyword(s):  
Theoretical Description ◽  
Fluid Interfaces ◽  
Interfacial Behavior ◽  
Current State ◽  
Air Interface ◽  
Direct Measurements ◽  
Wide Range ◽  
Dilational Viscoelasticity ◽  
Parameter Values ◽  
Β Lactoglobulin

The theoretical description of the adsorption of proteins at liquid/fluid interfaces suffers from the inapplicability of classical formalisms, which soundly calls for the development of more complicated adsorption models. A Frumkin-type thermodynamic 2-d solution model that accounts for nonidealities of interface enthalpy and entropy was proposed about two decades ago and has been continuously developed in the course of comparisons with experimental data. In a previous paper we investigated the adsorption of the globular protein β-lactoglobulin at the water/air interface and used such a model to analyze the experimental isotherms of the surface pressure, Π(c), and the frequency-, f-, dependent surface dilational viscoelasticity modulus, E(c)f, in a wide range of protein concentrations, c, and at pH 7. However, the best fit between theory and experiment proposed in that paper appeared incompatible with new data on the surface excess, Γ, obtained from direct measurements with neutron reflectometry. Therefore, in this work, the same model is simultaneously applied to a larger set of experimental dependences, e.g., Π(c), Γ(c), E(Π)f, etc., with E-values measured strictly in the linear viscoelasticity regime. Despite this ambitious complication, a best global fit was elaborated using a single set of parameter values, which well describes all experimental dependencies, thus corroborating the validity of the chosen thermodynamic model. Furthermore, we applied the model in the same manner to experimental results obtained at pH 3 and pH 5 in order to explain the well-pronounced effect of pH on the interfacial behavior of β-lactoglobulin. The results revealed that the propensity of β-lactoglobulin globules to unfold upon adsorption and stretch at the interface decreases in the order pH 3 > pH 7 > pH 5, i.e., with decreasing protein net charge. Finally, we discuss advantages and limitations in the current state of the model.

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