Geometric magnification is defined as the ratio of the projected X-ray image size to the actual sample size. It is calculated by dividing the distance from the X-ray focal point to the image detector (FID) by the distance from the focal point to the object (FOD).
Calculation Example: If an object is placed 100 mm from the X-ray source (FOD = 100 mm) and the detector is positioned 400 mm behind the object, the total distance from the source to the detector (FID) is 500 mm (100 mm + 400 mm).
Magnification = FID / FOD = 500 / 100 = 5x
While moving the detector further away increases geometric magnification, it also reduces the X-ray intensity reaching the sensor. Therefore, the most effective method to achieve high magnification is to shorten the FOD by positioning the object as close to the X-ray tube's focal point as possible.
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