Multi-pixel photon counter (MPPC) detectors

Hamamatsu Photonics has introduced an updated range of multi-pixel photon counter (MPPC) detectors. The MPPC technology has found uses in various applications from medical physics and high energy physics to general optical measurement applications.

The MPPC detectors use a Geiger-mode pixelated avalanche photodiode structure for ultra-low-level light detection. Each pixel contains a quenching circuit so that simultaneous photon events can be counted separately and with a high degree of accuracy. The detectors feature typical gain values from 250,000 to several million, depending on the specific device. The MPPC detectors also feature high photon detection efficiency from 320nm to 900nm. Unlike traditional photomultiplier tubes (PMT) the MPPC can be operated at low voltage (less than 80V) and they are insensitive to magnetic fields.

Some key areas of improvement to the MPPC include: greatly reduced dark count, reduced after-pulsing, increased photon detection efficiency, improvements in timing resolution and linearity, as well as reduced crosstalk. The result of these and other improvements means that the MPPC now has a much improved signal-to-noise ratio, wider operating voltage range, improved time resolution and a wider dynamic range.

As well as these improvements to the product range, there are also multiple new bare and modular solutions not previously offered. For example, Hamamatsu now offers a single pixel module, effectively taking a single MPPC pixel, of 50µm or 100µm diameter, and housing this within a cooled module. Dark counts as low as 7cps are easily achievable in this way.

The MPPC is ideally suited to a wide range of applications including positron emission tomography, high-energy physics, DNA sequencing, fluorescence measurement, nuclear medicine, point-of-care systems, drug discovery, medical diagnostic equipment, and environmental analysis, among many others.