  Nowadays, numerous fields such as High Energy Physics (HEP), medical imaging
devices, portable radiation detectors etc., require a robust, miniature,
reliable and readily available photon detector that is stable in a variety of
environments, such as the presence of strong magnetic fields. The recently
available $\sim$1mm$^{\textrm{2}}$ active area Multi-pixel Photon Counter
(MPPC) sensors, produced by Hamamatsu Photonics, have been found to be reliable
and an attractive choice for the HEP applications.
  The following sensor characteristics have been thoroughly tested by T2K
collaboration: gain, dark noise, detection efficiency, reliability. These
appear to be stable; in addition, the characteristic spread between numerous
devices was assessed. Sensors with larger area are being developed for imaging
and direct-to-scintillator coupling purposes.
