Rotating anode tubes

Unlike for synchrotron radiation, the maximum iatensity of x-rays from an x-ray tube is limited by how fast heat can be removed from the target to prevent its melting. In a conventional sealed tube, the target is stationary, relatively small, and must be continually cooled with water. In a rotating anode tube, the target is larger and is continually rotated so that the heat can be distributed over a larger surface. With such a tube the amount of heat, and hence. 

Sealed conventional fine structure tubes with Mo, W, Cu, or Cr anodes are used as primary X-ray sources, as well as rotating anode tubes, or synchrotron radiation. The maximum energy of the X-ray quanta determines the range of elements acces-... 

As noted above, the x-ray tube is a conventional laboratory source of x-rays. The two types of x-ray tubes in common use today are the sealed tube and the rotating anode tube. The sealed tube consists of a stationary anode coupled with a cathode, and both are placed inside a metal/glass or a metal/ceramic container sealed under high vacuum as shown in Figure 2.3. 

The method commonly used consists of using a rotating anode tube. This rotation, which is done at high speeds (2,000 to 6,000 rpm), makes it possible to work at powers of several thousand Watts per square millimeter. 

Most of the time, the rotating anode tubes are open tubes and ean be described by the diagram shown in Figure 2.7. 

Four different types of X-ray sources are employed in X-ray analysis (a) sealed X-ray tubes and (b) radioactive sources are the most commonly employed, while to a lesser extent primary X-rays produced in (c) rotating anode tubes and (d) synchrotron radiation facilities are also utilized for analytical purposes. 

In order to remove the limitation in the input power caused by excessive heating/melting of the anode in the SWT geometry, the rotating anode tube was developed. By employing a cylindrical anode head that rotates rapidly through the electron beam, an output power gain by a factor of 5-10 relative to... 

The 1 1 1 and rotating anode tubes are relatively recent developments for which the application field is still growing the most popular type of X-ray tube is still the SWT. 

Mo-W alloy anode) or a rotating anode tube. The beam is shaped like a strip of paper by means of precisely aligned slits its vertical divergence is adjusted to less than 0.01°. 

Figure 2 (A) Schematic sketch of a side window tube. (B) Rotating anode tube in two sectional views (1) cathode unit (2) filament (3) cylindrical anode with (3a) rotary shaft (4) window (5) electrical connections (6) cooling water connection (7) sealing gasket (8) vacuum flange. Reproduced with permission from Klockenkamper R (1997). Total Reflection X-ray Fluorescence Analysis. New York Wiley.

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