Why using a small focal spot in NDT radiography?

Image quality and exposure time are two major parameters for non-destructive testing.
Indeed, reducing exposure time will result in faster workflow… However, reducing exposure time can also result in a lower quality image with a loss of details and an increase of geometric un-sharpness which influences the ability to detect small defects.

Image quality

The geometrical un-sharpness is a blurring of details in an X-ray image and is defined by 3 parameters:
– The size of the focal spot
– The distance between the object and the source
– The distance between the object and the film
If one of those three parameters changes, the geometric un-sharpness will change as well.

Exposure time
We know that the focal spot size and the source to object distance are interconnected: if the focal spot size is reduced, the distance between the object and the film can be reduced as well.

This means if the focal spot is 1.0 mm instead of 3.0 mm:
–  the distance between the source and the film can be reduced by up to one-third
– the dose rate of X-rays will increase by a factor up to nine
– the exposure time, as a result, will be reduced by up to nine times

Teledyne ICM’s first small focal spot generator: the CP200DS

The small focal spot (1 mm) of the CP200DS generator minimizes un-sharpness and gives clearer images, which makes it ideal for digital radiography (DR) when close X-ray shots are possible.
Our CP200DS is a light and powerful generator (200 kV) with a metal-ceramic tube which turns it to be the best power-to-weight ratio in the world.
Its 100% duty cycle combined to its built-in multiple X-Ray outputs carousel make the CP200DS one of the most versatile generators on the market that will adapt to a very wide variety of NDT applications.
The CP200DS, like the rest of the CPSeries product range, operates with the plug-and-play POWERBOX control unit.

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