Seemann-Bohlin circles

Figure 16. Principle of the Guinier method a) Seemann - Bohlin circle b) Monochromator c) Reflection d) Specimen...

For many years, another method has been used to directly produce a digital signal using a Seemann-Bohlin diffractometer. Traditional film is replaced with a punctual detector moving along the focusing circle [WAS 53]. Usually, scintillation detectors or proportional gas detectors are used. The detector s movement can be either continuous or incremental. 

The Bragg-Brentano two-circle diffractometer has a Seemann - Bohlin focusing circle, on which the X-ray tube anode, the counter tube window, and the specimen are located (Fig. 27). Only the specimen is focusing. 

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