Lecture 2: x ray Production (PPT
... (3) Electric circuit to provide the heating currents. This is filament circuit which is different from the x-ray tube current. (4) Electrons are accelerated towards the anode. The x-ray tube current, measured in mA , refers to the number of electrons flowing per second from the filament to anode. ...
... (3) Electric circuit to provide the heating currents. This is filament circuit which is different from the x-ray tube current. (4) Electrons are accelerated towards the anode. The x-ray tube current, measured in mA , refers to the number of electrons flowing per second from the filament to anode. ...
transistor theory
... What happens at the pn junction when electrons and holes meet? Voltage pushes the electrons across the junction. They recombine with holes. Without this voltage pushing the electrons, the junction stays at thermal equilibrium ...
... What happens at the pn junction when electrons and holes meet? Voltage pushes the electrons across the junction. They recombine with holes. Without this voltage pushing the electrons, the junction stays at thermal equilibrium ...
Electricity Guided Notes
... Insulators-electrons _______ ________ flow easily through them Ex: rubber, paper, plastic, wood ...
... Insulators-electrons _______ ________ flow easily through them Ex: rubber, paper, plastic, wood ...
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.