There are two broad types of x-ray detector for our kind of work: Indirect detection involves converting the x-ray energy to optical photons, then detecting those with silicon based optical sensor arrays. In direct detection detectors the x-ray energy is directly converted to charge, which is then amplified and digitised under each pixel. IMBL has examples of both types.
Ruby
Our primary ‘work horse’ detector is the in-house designed Ruby imager. It uses a low noise scientific CMOS sensor to view optical light emission from a converter screen. The standard converter is a 25 micron thick Gadox powder (Gd2O2S:Tb), which emits light in the green part of the spectrum.
The sensor has 2560 horizontal by 2160 vertical pixels (5.5 MPix). The maximum frame rate is 100 fps (10 ms exposure).
Ruby can accept various lenses. The sensor to screen distance is variable allowing for a range of view fields. The finest resolution and smallest field of view is 16 mm by 14 mm, 6.3 micron pixels. With Ruby zoomed out it will view 110 mm horizontal by 93 mm vertical at 43 micron pixels.
Field of view (mm) | Pixelation/size (mm) | Full frame rate (fps) |
16.2 x 13.7 | 2560 x 2160 / 6.3 | 100 |
110 x 93 | 2560 x 2160 / 43 | 100 |