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Frequently Asked Questions

Why does CdTe have high absorption?

CdTe is a compound semiconductor made from cadmium and tellurium. Since the atomic number of both materials is high (Cd:48, Te:52) and CdTe has a high density (5.85g/cm3), it can absorb radiation more effectively.

What are the characteristics of CdTe detectors?

Due to its high density, CdTe is very radiation hard which means that it can be used in applications at very high energies (MeV). This radiation hardness also means that it has a longer lifetime than many other X-ray detectors, being resistive to radiative damage. CdTe detectors also have good spatial resolution and are extremely efficient which allows them to be used in very low dose situations.

What is CdTe?

Cadmium telluride (CdTe) is a stable crystalline compound formed from cadmium and tellurium and can be used as a compound semiconductor. CdTe is used in the next generation X-ray detectors. It absorbs radiation and efficiently converts it to an electronic signal.

What are the differences between CdTe and other radiation detectors?

CdTe is a direct conversion detector and as such does not need to turn the X-ray photon into a light photon before recording it. This means the position of the conversion can be more accurately recorded and the signal is directly related to the energy of the converted photon. Other radiation detectors use scintillators to convert X-rays to light. This process causes significant blur and loss of efficiency.

What is a “scintillator”?

A scintillator is a substance such as gadolinium oxysulfide or caesium iodide that converts an X-ray photon into a light photon. The light photons can then be recorded by a normal CMOS or CCD camera. Light photons travel in all directions, causing a loss of accuracy in spatial resolution. Typically, scintillation technologies are not as efficient as CdTe at stopping X-rays.