gamma and x-rays detection
... photomultiplier tube are determined by the composition of the photocathode. The best photocathodes capable of responding to visible light are less than 30 percent quantum efficient, meaning that 70 percent of the photons impacting on the photocathode do not produce a photoelectron and are therefore ...
... photomultiplier tube are determined by the composition of the photocathode. The best photocathodes capable of responding to visible light are less than 30 percent quantum efficient, meaning that 70 percent of the photons impacting on the photocathode do not produce a photoelectron and are therefore ...
About Electron Beams - E
... principle as a cathode ray tube (CRT) in a television set. Electrons are generated by heating a filament. A voltage gradient draws the electrons away from the filament and accelerates them through a vacuum tube. The resultant beam can then be scanned by means of an electromagnet to produce a “curtai ...
... principle as a cathode ray tube (CRT) in a television set. Electrons are generated by heating a filament. A voltage gradient draws the electrons away from the filament and accelerates them through a vacuum tube. The resultant beam can then be scanned by means of an electromagnet to produce a “curtai ...
Physics 3 - NYCC SP-01
... This is due to the conservation of energy. A transformer that raises the voltage is a step-up transformer; one that lowers voltage is a stepdown transformer. The determining factor in whether a transformer is step-up or step-down & to what extent it performs either of these tasks is the relative n ...
... This is due to the conservation of energy. A transformer that raises the voltage is a step-up transformer; one that lowers voltage is a stepdown transformer. The determining factor in whether a transformer is step-up or step-down & to what extent it performs either of these tasks is the relative n ...
Nanoscale field emission structures for ultra-low
... must be much less than the elastic mean free path of electrons in air ~about 200 nm at low electron energies!,5 and the operating voltage must be less than the first ionization potential of molecules present in air ~12.7 and 15.6 eV for nitrogen and water, respectively!.6 In this letter, we describe ...
... must be much less than the elastic mean free path of electrons in air ~about 200 nm at low electron energies!,5 and the operating voltage must be less than the first ionization potential of molecules present in air ~12.7 and 15.6 eV for nitrogen and water, respectively!.6 In this letter, we describe ...
Photomultiplier
Photomultiplier tubes (photomultipliers or PMTs for short), members of the class of vacuum tubes, and more specifically vacuum phototubes, are extremely sensitive detectors of light in the ultraviolet, visible, and near-infrared ranges of the electromagnetic spectrum. These detectors multiply the current produced by incident light by as much as 100 million times (i.e., 160 dB), in multiple dynode stages, enabling (for example) individual photons to be detected when the incident flux of light is very low. Unlike most vacuum tubes, they are not obsolete.The combination of high gain, low noise, high frequency response or, equivalently, ultra-fast response, and large area of collection has maintained photomultipliers an essential place in nuclear and particle physics, astronomy, medical diagnostics including blood tests, medical imaging, motion picture film scanning (telecine), radar jamming, and high-end image scanners known as drum scanners. Elements of photomultiplier technology, when integrated differently, are the basis of night vision devices.Semiconductor devices, particularly avalanche photodiodes, are alternatives to photomultipliers; however, photomultipliers are uniquely well-suited for applications requiring low-noise, high-sensitivity detection of light that is imperfectly collimated.