Glossary for quantities in the Hamamatsu data sheets:
Sk : Cathode Sensitivity, unit = micro Amps per lumen
Sp : Anode Sensitivity, unit = Amps per lumen
From these two quantities, the gain can be calculated as
Sp / Sk (in units of 10^6, because
A over uA)
Note the anode sinsitivity Sp here is measured with all channels ganged
together, namely the sum of 16 pixels.
Also, the light is shed on the tube through a slit with an aperture of
the size 18 mm times 18 mm,
bigger than the sensitive area.
That means the tube photocathode is exposed to light
uniformely over the entire cathode, independent of the position on the surface.
These two facts imply that the gain calculated in the way above
is that of the average over the surface of the
photocathode,
or, the average of the 16 channels.
Idb : Anode dark current, unit = nA
Skb : Cathode blue sensitivity (similar to Sk, but in particular to
blue light)
All these quantities are measured with a standard tungsten lamp (2865 K)
as a light source.
Also, the Corning filter CS 5-58 is
used to give blue light.
Tubes are applied with a HV of -800 V.