Boron lined proportional counters

Boron lined proportional counters

The Photonis boron-lined proportional counters (CPNB) are intended to measure neutron radiations in a source range of nuclear reactors and in all neutron source applications where safety is crucial. They operate at temperatures up to 200°C.

Detection of thermal neutrons in pulse mode
High safety of use
Customization according to the user’s needs
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Technical information

Boron lined proportional counters without integral cable

Basic type External diameter (mm) Length (mm) Neutron Sensitivity (cps/nv) Operating Range (nv) Max. operational temperature (°C)
CPNB28 25.4 368 5 2 x 10-1 – 4 x 105 200
CPNB48 25.4 560 10 10-1 – 2 x 105 200
CPNB65 76.5 727 25 5 x 10-2 – 5 x 104 200

Boron lined proportional counters with integral mineral insulated cable

Basic type External diameter (mm) Length (mm) Neutron Sensitivity (cps/nv) Operating Range (nv) Max. operational temperature (°C)
CPNB44 48 761 8 10-1 -2 x 105 200
CPNB64 76.5 741.5 25 5 x 10-2 - 5 x 104 200
CPNB84 82 741.5 42 5 x 10-2 - 3 x 104 200


Photonis boron-lined proportional counter work in pulse mode; it features a watertight HN connector. The Boron 10 is a solid layer deposited by Chemical Vapor Deposition (CVD) for Photonis counters that are qualified for the safety instrumentation start-up channels of more than 100 NPP in the world. Thin Boron 10 layers obtained by CVD process give unequaled life time and pulse resolution. Due to the extreme operating conditions of CPNB, Photonis also recommends the use of an integrated mineral insulated cable designed specifically for the detector.

Custom coaxial cable extensions & connectors

By full control of the following processes, Photonis Nuclear Instrumentation can supply boron-lined proportional counters with the highest quality and reliability levels

  • Adaptation of industrialized boron-lined proportional counters to customer specific requirements.
  • Development of new boron-lined proportional counters with our experienced R&D team.
  • Long term collaboration with the French Alternative Energies and Atomic Energy Commission  / CEA (theoretical approach, modeling, qualification tests in research reactors.
  • Complete manufacturing process on site.
  • Support from all the Photonis Group activities, experience and knowledge.
  • Certifications & Quality Assurance programs adapted to the customer environment.
  • Technical support, applying expertise.
  • Export control, as an Authorized Economic Operator, Photonis acts in accordance with the EU international regulations.

Examples of custom versions from basic types

Neutron sensitivity tailored to individual requirement

  • Adapted mechanical interface with the equipment (Customized external dimensions, springs, threads, hooks)
  • Ruggedized structure for harsh environment (radiation, temperature, humidity, mechanical stress)
  • Gaz reservoir option for higher life time
  • Integral cable or integral connector
  • Coaxial or triaxial mineral insulated cable
  • Mineral insulated connector type (Coaxial HN, BNC, BNC HT, SMA or triaxial solutions). Reinforced types are available for high pressure, high temperature conditions
Boron Lined Proportional counter

Main features

  • Structure configuration: Coaxial.
  • Structure material: Aluminum. 
  • Integral cable: Coaxial Mineral insulated cable for pulse transmission, high immunity. Integral cables are recommended for the signal and for the high voltage when operating in severe environments.
  • Connector: HN Mineral insulated connector for pulse transmission. 
  • Insulators: As it is necessary to measure extremely low currents, insulators must be of very high quality and radiation resistant. Photonis only uses high-grade alumina insulators from qualified suppliers.


The French Alternative Energies and Atomic Energy Commission  (CEA) selected Photonis as its technological partner for a co-operative development of neutron detectors when the French nuclear power program took shape in the sixties.

Our references

  • PWR – source range neutron flux monitoring – boron lined proportional counters CPNB44 – Belgium, China, France, South Africa, South Korea.
  • PWR – Boron concentration meters – boron-lined proportional counters CPNB48 - – France.
  • VVER – source range neutron flux monitoring – boron lined proportional counters CPNB – Armenia, Czech Republic, Hungary, Russia, Slovakia.
  • Fuel reprocessing plant – AREVA La Hague/ORANO – numerous boron-lined proportional counters – France, Japan.




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