Model 357BW


  • NEMA-12 enclosure
  • Plate-out proof wire-grid electrodes eliminate “background” zero drift
  • Gamma compensation (2L or 4L)
  • Range: 1 to 19,999 µCi/m3, 0.1 to 1,999.9 µCi/m3, 0.01 to 199.99 MBq/m3
  • ±5% accuracy over the entire measurement range
  • Audible and visual alarm indicators for signal level, low flow, and malfunction
  • Alpha pulse suppression, radon rejection
  • Long-term zero stable, span calibration is permanently stable due to special electrometer design
  • Options:
  • HTO only measurement, noble gas compensation
  • Upgraded heavy-duty pump system
  • Mounted on wheeled stainless-steel cart for portability


The Model 357BW is a single-range ionization chamber tritium in air monitor contained in a NEMA-12 enclosure suitable for permanent installation and continuous duty.  It is designed for the monitoring of rooms, glove boxes, fume hoods, exhaust stacks, as well as process piping.  The enclosure has a hinged door with a tempered glass window and is also double-hinged so that the inside components can be easily serviced.  The Model 357BW has an upgraded alarm system, including: high-level alarm (latching or non-latching), malfunction alarm (internal DC power supply or electrometer failure), and low flow alarm.  Exceptionally stable with accuracy and reproducibility of ±5% over the entire measurement range.

Dual 2L or quad 2L ionization chambers are available, with optional plate-out proof wire-grid electrodes to reduce tritium or other radioactive gas contamination by up to 1000x.  Quad 2L ion chamber assembly arranged in a cruciform geometry provides the best sensitivity, stability, and omnidirectional gamma compensation.

Translate »