Superconducting camera (SCAM)
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The superconducting camera, SCAM, is an ultra fast photon counting camera, developed by the ESA. It is cooled to just 0.3 K (300 thousandths of a degree above absolute zero). This enables its sensitive electronic detectors, known as superconducting tunnel detectors, to register almost every single photon of light that falls into it.
Its advantage over a CCD (charge-coupled device) is that it can measure both the brightness (energy) and the colour (wavelength) of a photon.
The number of free primary eletrons generated per photon event is proportional to the photon energy and amounts to ~18000 per [eletronvolt], and therefore if the device is operated in single-photon count mode the energy of each captured photon can be calculated in the visible-light range, where photons have energies of a few eletron-volts, each generating >20000 eletrons. In a normal CCD only one primary eletron is generated per each photon, except for very energetic photons, like X-Rays, where a normal CCD can operate in a similar way to a SCAM.
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