Compact size (16 mm diameter, 12 mm seated length), Fast Time response (rise time 0.78 ns)

The R7400U series is a subminiature photomultiplier tube with a 16 mm diameter and 12 mm seated length. A precision engineered 8-stage electron multiplier (composed of metal channel dynodes) is incorporated in the TO-8 package to produce a noise free gain of 700,000 times (R7400U). The R7400U series also features excellent response time with a rise time of 0.78 ns. Various types of the R7400U series are available with different spectral response and gain ranges, including those selected specifically for photon counting applications. Hamamatsu also provides a hemispherical lens input option to the series (R7401 and R7402), effectively doubling the active area.
 
FEATURES
● Worlds smallest photomultiplier tubes assembled in a TO-8 metal package (1/7th of the Hamamatsu R647).
   The necessary components are built into a TO-8 package while retaining full photomultiplier tube
   performance to create a new generation of photosensors.
● Photon counting type: R7400P.
   The R7400P is specially selected on account of low noise and high gain for use in
   photon counting applications.
● Hemispherical lens window types: R7401 (bialkali), R7402 (multialkali).
   The hemispherical lens window doubles the effective input area to 12 mm in diameter.