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Crookes tubes generated the electrons needed to create X-rays by ionization of the residual air in the tube, instead of a heated filament, so they were partially but not completely evacuated. They consisted of a glass bulb with around 10 −6 to 5×10 −8 atmospheric pressure of air (0.1 to 0.005 Pa ).
Crookes X-ray tube from around 1910 Another Crookes x-ray tube. The device attached to the neck of the tube (right) is an "osmotic softener". When the voltage applied to a Crookes tube is high enough, around 5,000 volts or greater, [16] it can accelerate the electrons to a high enough velocity to create X-rays when they hit the anode or the glass wall of the tube.
The kinetic energy of the electrons is converted into heat and radiation (X-ray photons) due to these interactions. Most of the energy carried by the electrons is converted to heat (99%). Only 1% is converted into radiation or X-rays. In order to assist with the dissipation of such high heat, a larger focal spot or focal track is needed.
Bremsstrahlung produced by a high-energy electron deflected in the electric field of an atomic nucleus. In particle physics, bremsstrahlung / ˈ b r ɛ m ʃ t r ɑː l ə ŋ / [1] (German pronunciation: [ˈbʁɛms.ʃtʁaːlʊŋ] ⓘ; from German bremsen ' to brake ' and Strahlung ' radiation ') is electromagnetic radiation produced by the deceleration of a charged particle when deflected by ...
The maximum energy of the produced X-ray photon is limited by the energy of the incident electron, which is equal to the voltage on the tube times the electron charge, so an 80 kV tube cannot create X-rays with an energy greater than 80 keV. When the electrons hit the target, X-rays are created by two different atomic processes: [citation needed]
Especially when artificially produced, synchrotron radiation is notable for its: High brilliance, many orders of magnitude more than with X-rays produced in conventional X-ray tubes: 3rd-generation sources typically have a brilliance larger than 10 18 photons·s −1 ·mm −2 ·mrad −2 /(0.1%BW), where 0.1%BW denotes a bandwidth 10 −3 ω centered around the frequency ω.
Artificial X-ray sources Radiopharmaceuticals in radiopharmacology. Radioactive tracer; Brachytherapy; X-ray tube, a vacuum tube that produces X-rays when current flows through it; X-ray laser; X-ray generator, any of various devices using X-ray tubes, lasers, or radioisotopes; Synchrotron, which produces X-rays as synchrotron radiation ...
As the energy (which is proportional to the peak voltage) of the stream of electrons in the X-ray tube increases, the X-ray photons created from those electrons are more likely to penetrate the cells of the body and reach the image receptor (film or plate), resulting in increased film density (compared to lower energy beams that may be absorbed ...