Topic
Anode ray
About: Anode ray is a research topic. Over the lifetime, 35 publications have been published within this topic receiving 309 citations. The topic is also known as: positive ray & canal ray.
Papers
TL;DR: The isotope problem was finally settled, but more accurate mass measurements showed that even isotopic weights differed to some extent from the whole numbers, which was the prerequisite for the discovery that isotopic ratios varied somewhat in nature.
Abstract: In 1815, the British physician William Prout had advanced the theory that the molecular masses of elements were multiples of the mass of hydrogen. This "whole number rule" (and especially deviations from it) played an important role in the discussion whether elements could be mixtures of isotopes. F. Soddy's discovery (1910) that lead obtained by decay of uranium and of thorium differed in mass was considered a peculiarity of radioactive materials. The question of the existence of isotopes came up when the instruments developed by J.J. Thomson and by W. Wien to study cathode and canal rays by deflection in electric and magnetic fields were steadily improved. In 1913, Thomson mentioned a weak line at mass 22 accompanying the expected one at mass 20 when he analyzed the mass spectrum of neon. Subsequently Aston obtained the mass spectrum of chlorine with masses at 35 and 37. Still in 1921, Thomson objected heavily to the idea of isotopes. The isotope problem was finally settled, but more accurate mass measurements showed that even isotopic weights differed to some extent from the whole numbers. Based on earlier ideas of P. Langevin and J.-L. Costa, F.W. Aston and A.J. Dempster developed the idea of packing fractions and mass defects due to the transformation of a portion of the matter comprising the atomic nucleus into energy. While the determination of the exact isotopic masses had improved over the years, the accurate determination of isotopic abundances remained a problem as long as photographic recording was used. Here especially A.O. Nier pioneered using dual collectors and compensation measurements. This was the prerequisite for the discovery that isotopic ratios varied somewhat in nature. M. Dole discovered the fractionation of oxygen isotopes by photosynthesis and respiration. Today 13C/12C-ratios are employed to detect adulterations of food and in doping analysis, and 14C/13C-ratios obtained by accelerator mass spectrometry are used for dating historical objects, just to give some examples.
90 citations
TL;DR: In this article, the authors describe some experiments which have been carried out in an endeavour to explain the precise nature of the reaction between the positive ions and the surface of the conductor.
Abstract: Modern theories of the glow and arc discharges require that electrons should be set free from the cathode surface as a result of the bombardment by positive ions. The conditions in the neighbourhood of the negative electrode are exceedingly complex, and it is only by systematic examination of each reaction which we believe to be present, isolated from the disturbing effects of the others, that we can hope for a complete understanding of this important region. This paper describes some experiments which have been carried out in an endeavour to explain the precise nature of the reaction between the positive ions and the surface of the conductor. The literature of this subject is fairly extensive, and many of the experiments have been very carefully thought out. It seems to be quite definitely established that ions of velocity greater than about 100 volts set free electrons from metal surfaces which are not rigorously freed from gas. Most of the experiments have been carried out with alkali ions from thermionic sources, and owing to the abnormally low ionisation potentials of the alkalis the results are scarcely applicable to the case of discharges in ordinary gas. We are not concerned with the liberation of electrons by very fast canal rays or alpha particles, but with the effect produced by positive ions of less than about 1000 volts energy. Penning has established by a series of experiments that neon ions of as little as 7 volts energy, drifting up against a metal surface, are able to set free electrons from it.
84 citations
25 citations
TL;DR: Wien as mentioned in this paper showed that the charged component in canal rays can be de ected using electric and magnetic fields, enabling Wien to roughly determine their mass-to-charge ratio.
Abstract: When Goldstein's report on the "positive light" (or what is known as "Kanalstrahlen", canal rays) in gas discharge tubes first appeared in 1886, Willy Wien had just finished his thesis at the Helmholtz Institute in Berlin. Eleven years later he performed his first experiments on canal rays and found that they consisted of inert, charged and neutral particles. The charged component in canal rays could be de ected using electric and magnetic fields, enabling Wien to roughly determine their mass-to-charge ratio. Improving vacuum conditions and detection efficiency, Thomson finally resolved the lightest constituents of canal rays: the hydrogen ions H+ and H2+. This marked the beginning of mass spectrometry. The first mass spectrographs were parabola-image instruments being used by Thomson to discover isotopes. Until about 1923, canal rays became the most common ion source. Also Aston used canal rays as an ion source for the first double focussing mass spectrometer. - Wien continued his work on canal rays up to the end of his life (he died in 1928). He investigated their interaction with matter, i.e. the mean free path of canal rays in gases with respect to charge exchange and atomic excitation. His particular interest was addressed to the physics of light emission by canal rays, such as the line spectrum and the splitting of these lines in magnetic and electric fields, the Doppler effect and lifetimes.
18 citations
Patent•
18 Feb 1999
TL;DR: In this article, a low-electron temperature region recess on an anode wall between a discharge chamber and an ion extraction port was constructed to stably feed a sufficient quantity of ions, particularly negative ions, with a small structure by forming a low electron temperature region.
Abstract: PROBLEM TO BE SOLVED: To stably feed a sufficient quantity of ions, particularly negative ions, with a small structure by forming a low-electron temperature region recess on an anode wall between a discharge chamber and an ion extraction port SOLUTION: A high discharge starting voltage is applied between an anode 4 and a cathode 5 to start an electric discharge The gas in a discharge chamber 3 is ionized by this electric discharge, thermoelectrons are emitted when ions collide with the cathode 5, and the gas in the discharge chamber 3 is converted into plasma An arc discharge occurs in the central axis direction of a tubular anode wall, and the occurrence of high-density plasma on and around the axis is accelerated The electric discharge occurs uniformly in the discharge chamber 3 at a high electron temperature, and high-density plasma is generated A recess 7 provided on an anode member 2 does not directly face the cathode 5, and a low-electron temperature discharge region is formed Dissociative bonding reaction is accelerated in this region, and many negative ions are generated in particular
13 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2013 | 1 |
| 2006 | 1 |
| 2002 | 1 |
| 1999 | 2 |
| 1997 | 1 |
| 1989 | 1 |