Model 593


  • Ultra-low-level resolution: 0.1 kBq/m3 (0.003 µCi/m3)
  • Range: 1 to 10,000 kBq/m3 (0.01 to 100 µCi/m3)
  • Gamma compensated, with 1” lead shielding around detectors to further reduce background noise
  • IP-54, NEMA-13 rated cabinet with polycarbonate window door and key locking latch
  • Measures HTO or Total Tritium (HT + HTO)
  • Sensitive to the only tritium; pollutants, radioisotopes (noble gases), aerosols, and particulates are removed and eliminated prior to measurement
  • The sophisticated signal processor analyzes pulse height and duration to select only recognizable tritium decay events and reject large amplitude or long duration gamma and cosmic ray effects and system noise


The Model 593 is the most sensitive tritium in air monitor that we offer and is designed for accurately measuring ultra-low levels of airborne tritium through use of a balanced pair of proportional counter detectors.  The Model 593 is sensitive to only tritium, a Nafion dryer (selectively permeable membrane) is used to isolate tritium oxide before measurement; all other sample constituents, including pollutants, radioisotopes (i.e., noble gases), aerosols, and particulates are removed and eliminated prior to measurement.  For measuring total tritium (HT + HTO), a catalytic oxidizer can be included to convert elemental tritium to tritium oxide.  The 593 features a large, color touch-screen LCD display and is housed inside an industrial IP-54, NEMA-13 rated cabinet with a polycarbonate window door and key locking latch on door.  Custom software allows you to view configure alarm settings, generate graphs, view trends, monitor and display malfunction and alert conditions, and log all data and events.

The 593 uses both electronic signal processing and a second, sealed proportional counter to eliminate the effects from external gamma fields.  1” lead shielding around the counter tubes further reduces background gamma and improves the statistical signal to noise ratio to enhance sensitivity.

This instrument requires a supply of P-10 gas for the operation of the proportional counting detectors.  Suggested cylinder size: 8.5 m3 (300 ft3), regulator set to a minimum of 50 kPa (7 PSI) and maximum 55 kPa (8 PSI).

Note: Model 593 requires approximately 40 minutes to reach 90% of the final value due to filtration of the tritium through the Nafion dryer.  If a faster response time or wider range is required, then please refer to Model 593.2 which utilizes a dual measurement system to provide a faster response time when tritium concentrations exceed 1 MBq/m3.

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