Boron lined proportional counters

Photonis boron-lined proportional counters (CPNB) measure thermal neutrons  to provide source range indication duringnuclear reactor operations and in all neutron source applications where safety is crucial. They operate in high gamma environments and at temperatures up to 200°C.

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

Boron lined proportional counters

Contact sales or request a quote

Contact us

Technical information

Boron lined proportional counters without integral cable


Basic typeExternal diameter (mm)Length (mm)Neutron Sensitivity (cps/nv)Operating Range (nv)Max. operational temperature (°C)
CPNB2825.436852 x 10-1 – 4 x 105200
CPNB4825.45601010-1 – 2 x 105200
CPNB6576.5727255 x 10-2 – 5 x 104200


Boron lined proportional counters with integral mineral insulated cable


Basic typeExternal diameter (mm)Length (mm)Neutron Sensitivity (cps/nv)Operating Range (nv)Max. operational temperature (°C)
CPNB4448761810-1 -2 x 105200
CPNB6476.5741.5255 x 10-2 - 5 x 104200
CPNB8482741.5425 x 10-2 - 3 x 104200


Enhancing Nuclear Safety with Photonis Boron-Lined Proportional Counters

Photonis Boron-Lined Proportional Counters (CPNB) are designed to measure neutron radiation in a wide range of nuclear reactors and neutron source applications where reliability and safety is paramount. These counters can operate at temperatures of up to 200°C.

  • Detection of thermal neutrons in pulse mode
  • Exceptional safety features
  • Fast counting times and long detector life
  • Customization to meet user-specific requirements

Photonis Boron-Lined Proportional Counters work in pulse mode and feature a watertight HN connector. Our proprietary B-10 coating, produced through the Chemical Vapor Deposition i.e. CVD process, provides unmatched durability, excellent pulse resolution, and high sensitivity- ensuring these counters meet safety instrumentation requirements for over 100 nuclear power plants worldwide. Given the challenging operating conditions of CPNB, Photonis also recommends the use of an integrated mineral-insulated cable designed specifically for the detector to minimize noise and required maintenance while extending useful life of the detector in high gamma environments.

In brief:

Photonis counters are qualified as safety-related instrumentation start-up channels for more than 100 nuclear power plants in the world. These boron-lined proportional counters work in pulse mode; they feature a watertight HN connector and may include an integral mineral insulated. The Boron-10 is a solid layer deposited by Chemical Vapor Deposition (CVD). Thin Boron 10 layers obtained by CVD process give unequaled detector life 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.

  • 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 Exosens Group activities, experience and knowledge.
  • Certifications & Quality Assurance programs adapted to the customer environment.
  • Technical support, applying our expertise in the design and manufacture of nuclear instrumentation to solve customer challenges.
  • Export control, as an Authorized Economic Operator, Photonis acts in accordance with the EU international regulations.

Examples of customization of standard parts

  • Neutron sensitivity tailored to individual application requirements.
  • Mechanical interface with the equipment (Customized external dimensions, springs, threads, hooks).
  • Ruggedized structure for harsh environment (radiation, temperature, humidity, mechanical stress).
  • Gas reservoir option for longer 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 and high temperature conditions.
Boron Lined Proportional counter

Main features

  • Structure configuration: Coaxial.
  • Structure material: Aluminum.
  • Integral cable: Coaxial mineral insulated cable for high immunity pulse transmission. 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: Photonis only uses high-grade, radiation resistant alumina insulators from qualified suppliers to ensure the measurement of extremely low currents.


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, Ukraine, Slovakia.
  • Fuel reprocessing plant – AREVA La Hague/ORANO – numerous boron-lined proportional counters – France, Japan.