Model 311


  • Modular configuration, highly customizable tritium monitor
  • Single measurement range up to 4.5 decades, single ionization chamber (not gamma compensated)
  • Select ion chamber size: single 2L, single 200mL, or single 50mL
  • Upgraded alarm system: two adjustable tritium level alarms, latching and non-latching alarm modes, optional malfunction and low flow alarms, and up to 3 alarm relays (two level, one malfunction)
  • Visual and audible alarm indicators
  • Alpha pulse suppression, radon rejection
  • Long-term zero stable, span calibration is permanently stable due to special electrometer design
  • Remote mounting of ionization chamber (25 feet standard)


The Model 311 features a single measurement range of up to 4.5 decades with a single ionization chamber (not gamma compensated).  Useful for applications that don’t require gamma compensation or for measuring high concentrations of tritium, such as during the manufacture, storage, and processing of tritium.  The Model 311 is part of our modular series designed for easy customization and features an upgraded alarm system that includes two adjustable tritium level alarms (alert level and high level) with audible and visual alarm indicators, acknowledge (mute) control, latching or non-latching alarm modes, and up to three alarm relays (two-level relays and one malfunction relay).  Optional alarm indicators include: low flow alarm and malfunction alarm (low voltage failure, high voltage failure, or electrometer failure).

The Model 311 typically supports three different chamber sizes, depending on your range and sensitivity requirements.  Select either: single 2L, single 200mL, or single 50mL.  Ionization chambers can be mounted remotely (up to 25 feet standard), or locally inside the electronics enclosure.

Typical Measurement Ranges:

Ci Bq
Single 2L: 1 to 19,999 µCi/m3 0.1 to 1,999.9 MBq/m3
Single 200mL: 0.1 to 1,999.9 mCi/m3
1 to 19,999 mCi/m3
0.1 to 1,999.9 GBq/m3
1 to 19,999 GBq/m3
Single 50mL: 0.1 to 1,999.9 mCi/m3

0.01 to 199.99 Ci/m3

0.1 to 1,999.9 GBq/m3

0.001 to 19.999 TBq/m3

Unique, gold-plated wire-grid ionization chambers are offered that are plate-out proof, reducing tritium/gamma contamination by up to 1,000x which is essential when measuring high levels of tritium.  Furthermore, we offer helium leak testing for any high-range application to ensure that there is no risk of leakage.

A wide variety of options are available, including: choice of data outputs (RS-232, Ethernet, 4-20mA), pump type and flowmeter assembly, system failure monitor, low flow alarm, remote display unit, helium leak testing, wire-grid ion chambers, gold-plated measurement chamber, HTO only measurement (noble gas compensation), and more.

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