Exosens product brand
Compensated Ionization Chamber

Compensated Ionization Chamber

Exosens' compensated ionization chambers deliver precise, reliable radiation detection in  mixed gamma and neutron environments. Designed to minimize signal drift from background gamma radiation, these chambers ensure accurate neutron flux monitoring in nuclear reactors and other safety-critical applications. Built for durability and long-term performance, they are ideal for demanding operations in power generation and research settings.

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Accurate Neutron Detection in mixed gamma and neutron radiation fields
Reliable, long-term Operation
Flexible customization to meet specific user applications - Customization according to the user’s needs
Guarded designs to maximizes signal-to-noise ratio

Compensated Ionization Chamber

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Technical information

Product[a]DiameterSensitive Length

Sensitivity[b][d] 

Material[g]CompensationType[h]
 (mm)[b][c](mm)[b][c]Neutron (A/nv)[e]Gamma (A/Gy/h)[f]   
IN3738.12101.4x10-142.5x10-10AluminiumCompensatedGuard Ring
IN335050110 - 2089.0x10-15 to 2.9x10-14 [i]AluminiumCompensatedGuard Ring
IN35731842.64x10-145.17x10-10AluminiumCompensatedGuard Ring
RC689.21045.65x10-15 to 2.14x10-14 [i]1x10-12 to 9x10-12 [i]AluminiumCompensatedDomed + Guard[j]

[a] Centronic have over 40 neutron ionisation chamber designs, table shows the most popular variants
[b] Nominal values stated
[c] Excludes any containment and/or termination compartments
[d] Standard Centronic tolerance on these devices is ±20%
[e] Using 10B enriched to >90% unless otherwise stated
[f] Based on 1 Gray = 114 Roentgen
[g] Products are typically rated to temperatures in the region of 200°C to 300°C, alternatives material are available to allow operation at high temperatures
[h] Design, materials and manufacturing process are common among most of these devices. Consequently operation capability is common and may be transferable. 
[i] Domed design allows for a more uniform 2π polar response 

Description

A compensated neutron ionization chamber is a specialized radiation detector used to measure neutron flux in environments where both neutrons and gamma radiation are present—such as near nuclear reactors. This type of chamber contains two closely matched ionization chambers: one utilizing with a neutron-sensitive material like boron, and the other without. Both chambers detect gamma radiation equally, but only one chamber responds to neutrons. By electronically subtracting the output of the gamma-only chamber from the neutron+gamma one, the device effectively eliminates the gamma contribution—isolating the neutron signal.

Gamma-compensated ionization chambers are particularly suited for high-flux, mixed radiation fields commonly found in the intermediate range during nuclear reactor operation. Their ability to compensate for gamma flux allows them to function accurately even at lower neutron flux levels, making them ideal for use in reactor control instrumentation and other safety-critical nuclear applications.

What We Offer:

We supply a comprehensive range of fission chambers optimized for demanding applications. Our portfolio includes:

  • High-flux capable chambers for power reactor monitoring and control.
  • Customized designs tailored to specific reactor conditions or experimental needs.
  • Harsh environment models for extended lifetimes in high temperatures and radiation levels.

Our expertise ensures reliability, precision, and safety in all neutron detection applications, supporting the operational excellence and regulatory compliance of nuclear facilities worldwide.
 

Custom compensated ionization chambers

With full control of the following processes, Exosens can supply custom Exosens uncompensated ionization chambers with the highest quality and reliability levels:

  • Adaptation of industrialized designs to customer-specific requirements utilizing significant operational experience
  • Development of new detectors with our experienced research and development teams.
  • Long-term collaboration with internationally renowned organizations for modeling, qualification tests and development.
  • Complete manufacturing and test process on site.
  • Support from all the Exosens group activities, experience, and knowledge.
  • Highly regulated Quality Assurance programs adapted to the customer’s environment.
  • Expertise in design and manufacture of nuclear instrumentation to solve customer challenges.
  • Export control, as an Authorized Economic Operator, Exosens acts in accordance with the EU international regulations.
  • Calibration measurements in high radiation flux

Examples of custom versions from basic types

  • Neutron and gamma sensitivity tailored to individual requirements.
  • Guard-ring (2 outputs) designs
  • Options for high temperature (>300°C) operation.
  • Adapted mechanical interface for installation (Customized external dimensions, springs, threads, hooks).
  • LOCA (Loss Of Coolant Accident) and post-LOCA protection.
  • Ruggedized structure for harsh environment (radiation, temperature, humidity, mechanical stress).
  • Integral cables or integral connectors.
  • Coaxial or triaxial mineral-insulated cable, as well as organic cables.
  • Customized connector type (BNC, HN, SHV and many others)

Main features

  • Structure configuration: Coaxial, guard-ring.
  • Structure material: Various material types utilized including aluminium and titanium.
  • Integral cable: Integral mineral insulated or organic cables options are available.
  • Connector: Customized connector type (BNC, HN, SHV and many others) 
  • Insulators: Exosens only uses high-grade, radiation-resistant insulators from qualified suppliers to ensure the measurement of extremely low currents.

References

  • Boiling Water Reactor (BWR)
  • MAGNOX
  • Advanced Gas-cooled Reactor (AGR)
  • Pressurized Water Reactor (PWR)
  • Water-Water Energetic Reactor (VVER)
  • Training Research Isotopes General Atomics (TRIGA)
  • Research Reactors
     

Documentation

Certificate

Brochure/Leaflet