Preamplifier Model 3002

The IAP Model 3002 represents the latest advance in charge sensitive preamplifiers designed for use with room temperature semiconductor detectors, particularly the silicon surface barrier type. The preamplifier converts the ionization charge developed in the detector during each absorbed nuclear event to a step function pulse output whose amplitude is proportional to the total charge accumulated in that event. The pulse decays exponentially with a time constant of 50 microseconds (nominal) to segregate successive events in high count rate applications.

As can be seen in the following schematic , the first stage functions as operational integrator yielding an output voltage proportional to the accumulated charge. The second stage functions as a selectable gain differentiator/buffer. The higher scale factor is especially useful for best signal-to-noise ratio in experiments involving low energy source. The differentiator circuit includes pole/zero adjustment to return the unipolar pulse signal to a reference baseline level without overshoot.




  • Detector Input: Accepts positive or negative charge pulses from semiconductor detectors
  • Test input: Accepts a positive or negative signal
  • Input impedance: 93 Ω
  • Gain: 2.5 V/V or 5 V/V
  • HV Input: ± 5000 Vdc



  • Inverting, pulse end.
  • Decay time: 50 μs (±10%)
  • Output impedance: 93 ohms
  • Offset: ± 50 mVDC (at gain of 9mV/MeV) or 0 ± 150 mVDC (at gain of 45 mV/MeV)



  • Integral Nonlinearity: Less than ± 0.02%
  • Charge Sensitivity: 0.2 V/picocoulomb or 1.0 V/picocoulomb, corresponding to 9 mV/MeV or 45 mV/MeV equivalent.
  • Power Requirement

+12 VDC- 2 mA

-12 VDC- 2 mA

+24 VDC- 30 mA

-24 VDC- 15 mA


Delivery Test

  • Power test
  • Match test the amplifier output with MCA input
  • Stability test
  • Spectroscopy test with DAS software


Installation Requirements 

  • Laboratory
  • A table for placing instrument
  • Bin power supply model and amplifier model 3600
  • Detector
  • Computer
  • The equipped room with an air conditioning for constant temperature and humidity
  • Power
  • Pulse generator


Long Term Warranty And After Sales Service

The warranty service includes the repair or service of the instrument and the free provision of services for replacing parts and repair wages for one year, but the warranty does not apply on the following cases:

  • Transport damages, electrical fluctuations, fire or heat, contact or penetration of water and corrosive chemicals, intense dust, lightning, natural disasters.
  • Instruments manipulated or repaired by persons other than the company’s representatives.
  • Any kind of manipulation or damage on installed holograms on the instrument.
  • Any displacement after installation without informing the company.
  • The warranty does not cover consumables.
  • After sales service is for 10 years with payment.

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