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Electron capture happens most often in the heavier neutron-deficient elements where the mass change is smallest and positron emission is not always possible. When the loss of mass in a nuclear reaction is greater than zero but less than 2 m e c 2 the process cannot occur by positron emission, but occurs spontaneously for electron capture.
The two types of beta decay are known as beta minus and beta plus.In beta minus (β −) decay, a neutron is converted to a proton, and the process creates an electron and an electron antineutrino; while in beta plus (β +) decay, a proton is converted to a neutron and the process creates a positron and an electron neutrino. β + decay is also known as positron emission.
During the formation of neutron stars, or in radioactive isotopes capable of electron capture, neutrons are created by electron capture: p + e − → n + ν e. This is similar to the inverse beta reaction in that a proton is changed to a neutron, but is induced by the capture of an electron instead of an antineutrino.
The figure on the right shows the electron spectrum of 203 Hg, measured by means of a magnetic spectrometer. It includes the continuous beta spectrum and K-, L-, and M-lines due to internal conversion. Since the binding energy of the K electrons in 203 Tl is 85 keV, the K line has an energy of 279 − 85 = 194 keV. Due to lesser binding ...
Neutron spectroscopy is a spectroscopic method of measuring atomic and magnetic motions by measuring the kinetic energy of emitted neutrons. The measured neutrons may be emitted directly (for example, by nuclear reactions ), or they may scatter off cold matter before reaching the detector.
In electron capture, some proton-rich nuclides were found to capture their own atomic electrons instead of emitting positrons, and subsequently, these nuclides emit only a neutrino and a gamma ray from the excited nucleus (and often also Auger electrons and characteristic X-rays, as a result of the re-ordering of electrons to fill the place of ...
Electron spectroscopy refers to a group formed by techniques based on the analysis of the energies of emitted electrons such as photoelectrons and Auger electrons.This group includes X-ray photoelectron spectroscopy (XPS), which also known as Electron Spectroscopy for Chemical Analysis (ESCA), Electron energy loss spectroscopy (EELS), Ultraviolet photoelectron spectroscopy (UPS), and Auger ...
In optical spectroscopy, energy absorbed to move an electron to a higher energy level (higher orbital) and/or the energy emitted as the electron moves to a lower energy level is absorbed or emitted in the form of photons (light particles). Because each element has a unique number of electrons, an atom will absorb/release energy in a pattern ...