Report on: ACTIVE VOLTAGE DIVIDER AND AMPLIFIER FOR

XP2282B, 51mm FAST TUBES, 8 STAGES

Note G0 France-1999/08/01-PM01

Object: Design report on the high voltage divider for the XP2282B PMTs

Authors:  Bosson G., Boyer B. and Stassi P. ISN Grenoble

Date:  January 8, 1999

 

ACTIVE VOLTAGE DIVIDER AND AMPLIFIER FOR

XP2282B 51mm FAST TUBES, 8 STAGES

  1. DESCRIPTION

    2. A low power photomultiplier voltage divider, using high voltage transistors ensure good linearity and high counting rates with a low stationary current .To obtain a long term stability an amplifier (gain 10) is connected and large output pulses can be obtain with low average anode current. To compensate the difference of energy between forward and backward, the gain can be reduced by a factor of five with a switch on the printed circuit board, without decreasing the high voltage.

  2. OPERATING CONDITIONS

    3. Output signal amplified pulse output signal

    Supply voltage anode grounded (-HV)

    Optimization of linearity and time characteristics, high count rate & long period stability

  3. VOLTAGE DIVIDER CHARACTERISTICS

    4. Operating voltage typ. 2500V

    max. 3000V

    Supply current 330m A /kV

    Dissipated power at max. Voltage 3 W

    Linearity within 1% at 2000V up to 20m A

    Two gain switched on the PCB 1 106 at 2500V (B type divider)

    2 105 at 2500V

     

  4. AMPLIFIER CHARACTERISTICS

    5. Voltage supply ± 6V

    Current supply ± 12 mA

    Offset ± 1 mV

    Gain 10

    Output impedance 50W

    Bandwidth 350 MHz

    Rise time 10-90% 1.7nS

    Fall time 10-90% 2nS

    Slew rate 2500V/m s

    B.L.R. stability within 1% up to ?

     

  5. ELECTRICAL DRAWING

    6.  

     

     

  6. COMPONENTS LOCATION ON PRINTED CIRCUIT BOARD

    7.

     

  7. TESTS

Several tests have been realized to improve the efficiency of the two-gain voltage divider and also of the amplifier.

A new XP2282/B04 tube coupled to a NE102 scintillator by mean of a small light guide, is used for the tests (see figure).

 

The anode signal of the base have been recorded in two conditions: with a 60Co source (370kBq), then with a 1 Gev Gamma beam produced by the GRAAL experiment on the ESRF accelerator. The rate measured on the detector, in this last case, was roughly 6.5 104 c/s.

60Co. Anode signal from the base in a "low-gain" position without amplifier (HV= -2kV). The left figure is constructed by average on 915 acquisitions.

60Co. Anode signal from the base in a "high-gain" position without amplifier (HV= -2kV). The left figure is constructed by average on 1685 acquisitions.

60Co. Anode signal from the base in a "low-gain" position with amplifier (HV=- 1.5kV). The left figure is constructed by average on 777 acquisitions.

Beam. Anode signal from the base in a "low-gain" position with amplifier (HV=- 1.5kV). The left figure is a single acquisition.