Search results
Results from the WOW.Com Content Network
Alpha spectrometry (also known as alpha(-particle) spectroscopy) is the quantitative study of the energy of alpha particles emitted by a radioactive nuclide that is an alpha emitter. As emitted alpha particles are mono-energetic (i.e. not emitted with a spectrum of energies, such as beta decay ) with energies often distinct to the decay they ...
An alpha particle X-ray spectrometer (APXS) is a spectrometer that analyses the chemical element composition of a sample from scattered alpha particles and fluorescent X-rays after a sample is irradiated with alpha particles and X-rays from radioactive sources. [1]
This choice also places K-alpha firmly in the X-ray energy range. Similarly to Lyman-alpha, the K-alpha emission is composed of two spectral lines, K-alpha 1 (Kα 1) and K-alpha 2 (Kα 2). [6] The K-alpha 1 emission is slightly higher in energy (and, thus, has a lower wavelength) than the K-alpha 2 emission.
A present day null constraint on the time variation of alpha does not necessarily rule out time variation in the past. Indeed, some theories [ 56 ] that predict a variable fine-structure constant also predict that the value of the fine-structure constant should become practically fixed in its value once the universe enters its current dark ...
The most common gamma-ray detector is a semiconductor germanium detector which allow for a greater energy resolution than alpha-particle spectroscopy, however gamma spectroscopy only has an efficiency of a few percent. Gamma spectroscopy is a less sensitive method due to low detector efficiency and high background.
Hydrogen-alpha, typically shortened to H-alpha or Hα, is a deep-red visible spectral line of the hydrogen atom with a wavelength of 656.28 nm in air and 656.46 nm in vacuum. It is the first spectral line in the Balmer series and is emitted when an electron falls from a hydrogen atom's third- to second-lowest energy level.
Energy-dispersive X-ray spectroscopy (EDS, EDX, EDXS or XEDS), sometimes called energy dispersive X-ray analysis (EDXA or EDAX) or energy dispersive X-ray microanalysis (EDXMA), is an analytical technique used for the elemental analysis or chemical characterization of a sample. It relies on an interaction of some source of X-ray excitation and ...
Generally this topic is discussed when covering tandem mass spectrometry fragmentation and occurs generally by the same mechanisms. [3] [4]For example, of a mechanism of alpha-cleavage, an electron is knocked off an atom (usually by electron collision) to form a radical cation.