Skip to content

9349 Log/Lin Rate Meter

ORTEC 9349 Log/Lin Rate Meter
  • For counting rate measurements with photons or ion beams
  • 106 counts/s full scale
  • Linear or logarithmic operation
  • Fast negative NIM input

Designed for photon or ion beam applications, the ORTEC Model 9349 Log/Lin Ratemeter provides two modes of operation: linear and logarithmic. The linear mode has 11 full-scale ranges from 10 to 106 counts/s in 1-3-10 steps. The 5-decade log mode covers the range 10 to 106 counts/s in a single span. These choices permit optimum measurement of low, medium, or high steady pulse rates or monitoring of rates that vary through a wide range.
  • Literature +

  • More Information +

    The input signal to the Model 9349 is normally obtained from a discriminator having a NIM-standard, fast-negative logic output signal.

    Because of the longer effective scale inherent in its 240° movement and its high accuracy, the unique circular front-panel meter provides excellent readability for both modes. 

    Zero suppression is provided for up to 100% of any linear range. Any relatively constant background in the counting rate can be subtracted from the data by adjustment of this control. Also, a suppressed zero permits rates that are beyond the nominal full-scale limit to be observed with greater accuracy than could be obtained by switching to a higher range. The choice between 7 linear and 2 log time constants is a further aid to accurate reading of the rate of incoming signals. 

    In addition to the front-panel meter indications, outputs are provided for both current and voltage recorders, as well as a high-level voltage output for control or monitor applications.
  • Specifications +


    11 ranges from 10 to 106 counts/s full scale in 1-3-10 steps.
    Dead Time <100 ns on the 106 range; <0.3% of average pulse spacing up to the 3 X 104 range; ≤1% on the 105 and 3 X 105 ranges.
    Rated Overload Maintains full-scale output for X300 overload or 107 counts/s, whichever is smaller.
    Temperature Instability ≤±0.05%/°C.
    Nonlinearity ≤±0.15% from 10 to 3 X 104 counts/s range; ≤±1.5% from 105–106 counts/s.
    Time Constants 7 selectable time constants, 0.03 to 30 s in 1-3-10 steps.
    Zero Suppression 0 to 100% of full scale, nonlinearity ≤±0.25%.

    One 5-decade range for 10 to 106 counts/s.
    Temperature Instability ≤±0.25% of full scale per °C.
    Analog Output Error ≤±2.5% of full scale.
    Standard Deviation ~15% with Log Short time constant; ~5% with Log Long time constants.
    Slewing Rate Dependent upon input rate; for any rate change, Log Short time constant provides 10 times faster response than Log Long time constant.


    12-position switch selects the full-scale range and either linear or logarithmic mode; linear ranges are 0–10 counts/s through 0–106 counts/s in 1-3-10 steps; log range is 10–106 counts/s.
    Time Constant 9-position switch selects the time constant for the integrating network; 0.03 to 30 s in a 1-3-10 series for all linear ranges; Short and Long for the log range.
    Zero Suppression 10-turn precision potentiometer to suppress the zero-reference level for any linear range from 0 to 100%; the same full-scale span is effective above the preselected zero-reference level.

    Rear-panel BNC connector accepts NIM-standard, fast-negative logic signals, –600 to –1800 mV. Zin = 50 Ω. Minimum pulse width is 4 ns FWHM.

    Panel Meter
    240° circular movement with 8.9 cm (3.5 in.) deflection; accuracy, 2% of full scale; 3 scale markings; 0–1 and 0–3 for linear ranges and 10–106 in 5 decades for log range.
    Analog Outputs BNC connector on rear panel provides 0 to 10 V full scale, dc-coupled with 100-Ω output impedance.
    Recorder Outputs Binding post connectors on rear panel:
    • 100 mV  Provides voltage output with 100 mV full scale; dc-coupled with 100-Ω output impedance.
    • 1 mA  Provides current output of 1 mA full scale; dc-coupled with 10 kW output impedance.

    Electrical and Mechanical
    Power Required
    +24 V, 50 mA; –24 V, 35 mA; +12 V, 30 mA; –12 V, 45 mA.
    Weight Net   1.5 kg (3.5 lb).   Shipping   2.5 kg (5.5 lb).
    Dimensions NIM-standard double-width module 6.90 X 22.13 cm (2.70 X 8.714 in.) per DOE/ER-0457T.
  • Ordering Information +

    Model       Description
    9349 Log/Lin Rate Meter