3.2 Detectors
A radiation detector is a device that can sense the presence of incident radiation by producing a measurable effect.
X-rays can be measured through the physical effects of their interactions with matter. The measurements are based mainly on the ionizing properties of the x-rays and the use of instruments that convert the radiation to electrical signals. The x-ray detectors function by the following processes:
A non-conducting or semi-conducting material is allocated between two charged electrodes.
X-rays ionize the detector material causing it to become conductive, momentarily.
The newly freed charge carriers are accelerated toward the detector anode to produce an output pulse.
The main characteristics of the x-ray detectors are their sensitivity to detect the x-rays (efficiency), the capability of producing a signal proportional to the energy of the detected photons or not, and if so, the energy/wavelength resolution (capability of differentiating signals from photons with close energies).