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266 Photomultiplier Base

ORTEC Model 266 Photomultiplier Base
  • For use with 10-stage PMTs that fit standard 14-pin sockets
  • Linear output available from anode or tenth dynode
  • Focus control for optimum performance

The ORTEC Model 266 Photomultiplier Base provides voltage distribution to essentially all 10-stage photomultiplier tubes (PMTs) that fit its standard 14-pin tube socket. It provides capacitively-coupled linear output signals from the anode and the tenth dynode that can be used in either timing or linear pulse height analysis systems. This arrangement allows the use of either polarity of output without an inverting amplifier. High-quality signals are maintained when these outputs are fed through 50-Ω terminated cables or directly into a linear preamplifier such as the ORTEC Model 113 Scintillation Preamplifier. The Model 113 output is fed into one of the ORTEC main amplifiers, where it can be either active-filter- or delay-line-shaped for analysis. The focus control on the Model 266 allows optimum adjustments for the best performance of the particular PMT.
  • Literature +

  • Specifications +

    Bleeder Resistance
    1.5 MΩ total, tapped to provide proportional bias steps to successive tube elements.


    The voltage to the focus electrode in the tube is available as an external trim adjustment using a screwdriver potentiometer.

    POS HV
    SHV connector accepts positive bias voltage to 2.5 kV maximum.
    PMT Socket TRW 3B14. Fits JEDEC B14-38 PMT pin base.

    BNC connector provides negative linear output through Zo ~1.1 MΩ, capacitively-coupled.
    Dynode BNC connector provides positive linear output from the tenth dynode through 1.1 MΩ, capacitively-coupled.

    Electrical and Mechanical
    Net  0.37 kg (0.81 lb).   Shipping  0.96 kg (2.12 lb).
    Dimensions 5.6 cm (2.2 in.) diam x 10.2 cm (4 in.) long.
  • Related Equipment +

    Either the anode or dynode signal may be processed through an ORTEC Model 113 Scintillation Preamplifier that is connected to a main shaping amplifier such as ORTEC Models 460, 570, 572A, 575A, or 590A. These signals may also be connected through 50-Ω coaxial cables and amplified by fast amplifiers to be used in timing applications with a fast timing discriminator. If one of the outputs is not used, it should be terminated with a C-27 100-Ω terminator to prevent distortion on the other outputs. The ORTEC Model 556 High-Voltage Power Supply is recommended for supplying the positive high voltage. A C-24-1 Cable is recommended for connecting the dynode output to a Model 113 Preamplifier. A C-24-12 Cable can be used between the preamplifier output and the input to the main shaping amplifier. For timing from the anode use a C-25-12 Cable. The C-36-12 Cable is recommended for the high voltage  connection.
  • Ordering Information +

    Model Description
    266 Photomultiplier Base
    C-24-1 RG-62A/U 93-Ω cable with two BNC male plugs, 1-ft. length
    C-24-12 Same as above, 12-ft length.
    C-25-12 RG-58A/U 50-Ω cable with two BNC male plugs, 12 ft length
    C-36-12 RG-59A/U 75-Ω cable with two SHV female plugs, 12-ft length
    C-27 Terminator, 100-Ω, BNC male plug