Kromek develops, manufactures and integrates detectors which use the CdTe family of materials. These materials are employed as direct converters of x ray and gamma ray photon energy into electrical signals. These detectors differ significantly in their operation and output from traditional detectors such as Si diode scintillators which indirectly generate output through use of an x ray scintillator.

Direct-conversion detectors convert X-ray photons into an electric charge with no intermediate materials.

Indirect-conversion detectors, on the other hand, have a scintillator that first converts X-rays into visible light. That light is then converted into an electric charge by means of photodetectors Si diodes.

These operating mechanisms lead to specific advantages for direct converters.

	Direct detectors	Indirect detectors
Efficiency	Very high efficiency can be achieved because of the high x ray stopping power of the detector	Efficiency is limited by the poor x ray stopping power of the scintillator
Size	Small detector sizes are usable due to their high efficiency	Small detectors such as are required for imaging have limited performance
Energy resolution	Since each photon is individually converted into electrical charge then the quantity of charge represents the energy of the photon precisely.	Simple indirect conversion cannot distinguish between many low energy photons and one high energy photon. Energy resolution is only achieved through filtering techniques
Data quality	High quality data with very precise energy calibration from each photon can be achieved in short times with low dose rates	Long times or high dose rates are required to compensate for low efficiency. Only very approximate energy calibration can be achieved. Poor contrast is obtained due to not treating every photon separately

Detector electronics

In order to make use of these properties specific electronics is required. Since the energy of each photon is individually examined the sensitivity of the electronics is much higher for direct converters rather than indirect converters. Kromek have developed a suite of electronics to handle both imaging and non imaging applications of CdTe detectors.

Detector software

One of the significant problems of direct converter detectors can be the sheer volume of information generated. Each detector can give a fully spectral signal for the x rays hitting it and can provide the variation of this spectrum over very small time increments. In order to avoid being swamped by confusing data Kromek provides an application layer which easily presents the data the customer requires in their particular application and avoids the need to understand fully x ray spectra information