A positron is an antimatter counterpart of the electron with a positive charge. A proton is a baryon particle found in the nucleus of atoms with a positive charge.
The short-lived positron emitting isotopes 11C, 13N, 15O and 18F used for positron emission tomography are typically produced by proton irradiation of natural or enriched targets. 用于断层扫描的半衰期很短的正电子发射同位素11 C、13 N、15 O和18 F通常由天然核反应或人工用质子轰击富集的靶获得。
Thus the mean distance between the electron and the positron in Ps is twice that between the electron and the proton in the hydrogen atom. Another electron can also bind to Ps weakly to form a positronium negative ion (e−e+e−, Ps−). Ps− is a bound state through Coulomb ...
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Positron lifetime is obtained by measuring the time difference between the detection of the 1.28MeV γ-ray and the detection of the 0.511MeV γ-ray that is emitted as the consequence of the positron–electron pair annihilation (γ–γ coincidence method). The positron annihilation rate (...
摘要: We present a novel culling algorithm that uses deforming non-penetration filters to improve the performance of continuous collision detection (CCD) algorithms. The underlying idea is to use a simple and effective filter that reduces both the number of ......
PURPOSE:To dispense with a delay time control circuit and to eliminate sensitive difference between simultaneous count circuits by mounting simultaneous count circuits each detecting the simultaneity of the signal between the outputs of two groups among a plurality of the radioactivity detector groups divi...
Any difference in the apparent size of the proton, when determined from ordinary versus muonic hydrogen, could point to new physics or need for the higher order corrections. While recent measurements seem to now be in agreement, there is to date no high precision elastic scattering data with ...
Let us take a look of a system consisting of proton+two electrons+positron, where the positron might be seen to play a role of an extremely light second nucleus in such a “hydrogen molecule.” If the corresponding “atoms” (the hydrogen atom and the positronium) did not interact, one ...
The differential positron annihilation spectroscopy (DPAS) is used for the nondestructive investigation of thin metallic coatings on metallic substrates when the defectiveness of the coating applied is judged from the difference between the spectra of the individual substrate and the substrate covered with...