HV Bases

HV bases are a very convenient and cost-effective way to avoid external high voltages while allowing full adjustment of the individual photomultiplier operating voltage for optimum performance. There are two basic design configurations to choose from:

Active divider types (AN and AP), which have an active voltage divider operating from a separately generated high voltage. These offer the best noise performance but use more power than the Cockroft Walton design. They are particularly suitable for dc applications.

Cockroft Walton types (CN and CP), in which the high voltage is generated directly at the dynodes of the photomultiplier thus removing the need for a voltage divider. This approach results in a much lower power consumption but is traditionally more noisy, making them less suitable for dc applications but ideal for photon counting use, especially in battery-driven instruments.

Both designs are available with positive or negative HV polarity and versions are available for most of the popular photomultipliers types from 29mm to 130mm diameter with other options being available to special order. 

See below for a performance summary of these different designs


Summary of Characteristics

    AN Types      AP TypesCN typesCP types
Supply Voltage (V) +5 to +15 +5 to +15 +5 to +15 +5 to +15
Supply Current at 5V (mA):        
  for anode current 0uA 70 70 1.5 1.5
  for anode current 100uA 150 150 6.5 6.5
Supply Current at 12V (mA):        
  for anode current 0uA 40 40  1 1
  for anode current 100uA 60 60   5  5
Control Voltage (Vc:HV) 1:1000 1:1000 1:1000 1:1000
Output Voltage (max, V) -2000  +2000  -2000  +2000
Output Current (max, uA) 200 200 200  200
Line regulation (%/V) <0.01 <0.01   <0.01   <0.01
Load Regulation (%):        
  for anode current 0-100uA <0.01 <0.01 <0.01 <0.01
Anode ripple (mV p-p)  1 2  1  2
Switch-on time (s)  0.2 0.2  0.2 0.2
Switch-off time (s)  3 3 25 55


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