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typical rotating anode X-ray tube A considerable amount of heat is generated in the focal spot (the area where the beam of electrons coming from the cathode strike to) of a stationary anode. Rather, a rotating anode lets the electron beam sweep a larger area of the anode, thus redeeming the advantage of a higher intensity of emitted radiation ...
In general, an X-ray's beam intensity is not uniform. When it focuses to a target, a conical shape appears (divergent beam). The intensity of the beam from the positive anode side is lower than the intensity from the negative cathode side because the photons created when the electrons strike the target have a longer way to travel through the rotating target on the anode side.
William David Coolidge (/ ˈ k uː l ɪ dʒ /; October 23, 1873 – February 3, 1975) [1] was an American physicist and engineer, who made major contributions to X-ray machines. He was the director of the General Electric Research Laboratory and a vice-president of the corporation.
An illustration of the heel effect in an x-ray tube. In X-ray tubes, the heel effect or, more precisely, the anode heel effect is a variation of the intensity of X-rays emitted by the anode depending on the direction of emission along the anode-cathode axis. X-rays emitted toward the anode are less intense than those emitted perpendicular to ...
With rotating envelope tubes, the entire vacuum tube rotates with respect to the anode axis, versus rotating anode tubes, in which the target disk rotates inside a stationary vacuum tube. The target cools by conduction rather than radiation. Heat storage is less important, and waiting times are eliminated. [1]
X-ray diffraction is a generic term for phenomena associated with changes in the direction of X-ray beams due to interactions with the electrons around atoms. It occurs due to elastic scattering, when there is no change in the energy of the waves. The resulting map of the directions of the X-rays far from the sample is called a diffraction pattern.
To obtain high-quality data in X-ray CTR measurements, it is desirable that the detected intensity be on the order of at least [citation needed]. To achieve this level of output, the X-ray source must typically be a synchrotron source. More traditional, inexpensive sources such as rotating anode sources provide 2-3 orders of magnitude less X ...
Anomalous X-ray scattering (MAD or SAD phasing) – the X-ray wavelength may be scanned past an absorption edge [a] of an atom, which changes the scattering in a known way. By recording full sets of reflections at three different wavelengths (far below, far above and in the middle of the absorption edge) one can solve for the substructure of ...