This European standard specifies a method for the measurement of effective focal spot
dimensions below 0,1 mm of X-ray systems by means of the reconstruction technique, applied to
digital images taken from hole type or disk type gauges. The imaging quality and the resolution of
X-ray images depends highly on the characteristics of the effective focal spot, in particular the size
and the two-dimensional intensity distribution as seen from the detector plane.
This method can also be applied for the measurement of effective focal spot dimensions above or
equal to 0,1 mm, but the application of the pin hole method of EN 12543-2 is preferable.
This document provides instructions for determining the effective size (dimensions) of mini and
micro focal spots of industrial X-ray tubes for users in applications where the pin hole method of
EN12543-2 is not practicable. This determination is based on the measurement of profiles of an
image of a hole or disk type gauge and the reconstruction of the 2D distribution.
The use of the pin hole method (ASTM E 1165, EN 12543-2) requires the application of special
pin hole cameras. This procedure describes, how the 2D spot shape and size of focal spots can
be determined from hole or disk exposures, which are easier to produce in comparison to pin holes
and the related cameras.
Microfocus (1 μm ≤ spot sizes < 0,1mm) and nanofocus tubes (spot sizes < 1 μm) have a
significantly lower photon flux than mini and macro focus tubes (spot sizes ≥ 0.1 mm).
Furthermore, pin holes (see EN 12543-2 or ASTM E 1165) with diameters in the nm and μm region
are difficult to manufacture and will not permit a sufficient photon statistic for digital imaging with
the required magnifications. Nano- and micrometre pin hole methods would require very long
exposure times for obtaining a sufficient SNR and CNR
ABANDON
cen:proj:79158
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Project deleted
Apr 10, 2025
