The aims of the group are to provide support and assistance to the beamlines in all detector areas and to develop new detector systems to cope with future needs.

The detector group at Diamond works in collaboration with the beamline scientists to provide a number of different types of specialised x-ray detectors for synchrotron light experiments. This ranges from purchasing off-the-shelf detectors to developing completely new detector systems.

The high energy photons (X-rays) produced by Diamond are exploited as a probe for measuring the characteristics of  samples. The properties of the photons after they interact with the sample have to be measured by detectors, which vary according to the particular application. This can include the photon flux distribution as a function of space or time, the photon spectral distribution, their space or time correlation, just to mention a few.

The principles of the interaction of high energy photons with matter are exploited by the detectors used at Diamond. The high energy photons produce high energy charged particles that in turn produce free electric charge (secondary ionization) in the detector's sensor. This electric charge produced by the secondary ionization ts detected by electronic systems.

The three main mechanisms that lead to the high energy charged particles are the photoelectric effect, the Compton effect, and pair production. Only the first two are relevant here as the last one takes place at energies that cannot be reached by Diamond.

The free charge produced by the interaction of radiation with matter can be exploited to generate directly an electric signal in the read-out electronics (direct detection), such as in semiconductor detectors or gas filled detectors, or converted to a different form of energy, such as light in the case of scintillators or heat in the case of bolometers, before generating a signal in the electronics (indirect detection).

The read-out electronics almost always includes two additional functions to the conversion to digital data. The first is amplification to increase the amplitude of the signal delivered by the sensor to a level suitable for the digital conversion. The second is signal processing to improve the signal to noise ratio. This second function can be implemented with some analogue circuitry or with a digital algorithm implemented in the detector firmware.

The data are then acquired and storaged by digital computers for future analysis.

Detector Group Members