Na₂KSb photocathode material with 28mm (1-1/8") diameter side-on PMT.
 
Technical Specifications
Active Area Diameter or Length: 18 mm
Active Area Height: 16 mm
Cathode Radiant Sensitivity: 62 mA/W
Window: UV Glass Fused Silica
Cathode Luminous Sensitivity: 50 μA/lm 
Cathode Blue Sensitivity Index: 7 
Anode Luminous Sensitivity: 300 A/lm
Gain: 6.0E+06 
Dark Current: 0.5 nA (typ.)
Rise Time: 1.2 ns (Typ.)
Transit Time: 18 ns 
Transit Time Spread: 1.2 ns 
Number of Dynodes: 9 
Applied Voltage: 1000 V