FNS 100 – Fast Neutron Spectrometer 100


Overview

The FNS-100 is a high efficiency, high resolution fast neutron spectrometer. The detector is a multi-wire 3He ion chamber with a dense quenching gas. The availability of both high efficiency and exceptional resolution in one instrument makes the FNS-100 useful for nuclear science and engineering, materials research and radiation protection.

The FNS-100 is supplied with an integral cadmium and boron shield to reduce its sensitivity to thermal neutrons. The residual thermal neutron peak is a convenient feature for energy calibration and stability monitoring. The FNS-100 spectrometer, as provided with custom preamplifier and notch filter, is fully compatible with standard spectroscopy electronics (not provided) like those used with Ge spectrometer systems.

  • Unsurpassed resolution < 20 keV (thermal peak)
  • Matched preamplifier
  • Notch filter for reduction of microphonics
  • Compact, lightweight

Technical Specifications

  • Spectral Range 0.1 - 5.0 MeV
  • Resolution - Thermal < 20 keV FWHM
  • Resolution - 1 MeV < 30 keV FWHM
  • Efficiency, Absolute at 1 MeV 3 x 10-4
  • Detector Size 6.4 x 57.4 cm or 2.5 x 22.6 in (diameter x length)
  • Effective Length 15 cm (9 in)
  • Preamplifier Size 11.0 x 8.0 x 4.0 cm (4.3 x 3.1 x 1.6 in)
  • Anode Bias +3000 V
  • Grid Bias +850 V
  • Preamplifier +/- 12 V (NIM std)
  • Output Amplitude -50 mV/MeV
  • Output Impedance 50 ohms
  • Risetime 0.2 to 5 microseconds (10 to 90%)
  • Falltime ~1 millisecond
  • Shaping 4 microsecond Gaussian

Resources