Neutron Survey Meter

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The NSN3 portable neutron survey meter measures the neutron ambient dose equivalent rate. It is intended for the protection of workers in nuclear facilities and throughout the fuel cycle, research centres, particle accelerators and civil protection first response teams. 

Portable Neutron Survey Meter NSN3

Portable Neutron Survey Meter NSN3

Engineered for reliability in challenging environments, Fuji Electric's NSN3 Neutron Meter is an innovation in neutron measurement technology.

The compact unit, with its weight of roughly 7 pounds (3kg), has been thoughtfully designed for seamless handling and mobility.
It excels in its capacity to measure both thermal and fast neutrons up to an energy range of 15MeV, offering unrivaled H*(1cm dose equivalent) measurement performance.

Constructed from high-grade polyurethane, the robust exterior shell of the NSN3 has been put through rigorous testing, guaranteeing high strength and longevity. The portability of this device makes it a perfect fit for scenarios with potential hazards such as high temperatures, difficult climbs, or restricted spaces. Make every neutron count with Fuji Electric's lightweight and durable NSN3 Neutron Meter.

  1. Lightweight 
  2. No He-3 or Bf-3 
  3. Wide Range Measurement

The protection of workers exposed to radiation requires the control and monitoring of the level of contamination of sites before and during your interventions.

  • Reduce the duration of your on-site interventions thanks to easy deployment and handling
  • Optimise your measurement campaigns
  • Choose reliability with high-precision measurements and data collection
  • Facilitate the recovery of collected data   


What is a portable neutron survey meterWhat is a portable neutron survey meter?

By the ICRP* recommendations, the survey meter for neutron is used for the detection of contamination and the evaluation of the ambient dose equivalent H*(10) before fieldwork, before handling an object and when searching for hot spots. It allows rapid and immediate measurements of neutron radiation.

It is a complementary support to dosimetry for the protection and safety of workers.
*ICRP (International Commission on Radiation Protection)


How does the neutron survey meter NSN3 work?

FUJI Electric's neutron survey meter principle major innovation is using an organic gas mixture of methane and nitrogen instead of 3He or BF3.


How are neutrons detected ?

The elastic diffusion reaction of hydrogen from methane detects fast neutrons. Thermal neutrons, slow neutrons are detected using the 14N (n,p) 14C reaction of nitrogen. The proton energy in this reaction is 626 keV.
By these two reactions, the neutron ambient dose equivalent can be measured from 0.025 eV up to 15 MeV.
This unique and patented technology, the result of Fuji Electric's R&D, allows high sensitivity to be achieved with a minimum of moderators in an ultra-light and handy device.



The Portable Neutron meter NSN3 is designed for professionals exposed to radiation

NSN3 is designed for professionals exposed to radiationReduce the time spent on site with easy deployment and handling

The NSN3's portability and low weight of only 3kg make it easy to monitor.
Designed for adaptability in the field, the NSN3 operates on rechargeable or non-rechargeable batteries. It offers a long battery life of more than 12 hours of continuous display and more than 31 hours of non-displayed time.
It can also be used continuously via a main supply.


Optimise your NEUTRON measurement campaigns

The neutron dose survey meter can be used in portable or stationary mode.
Record your data (up to 1200 points) and transfer it to the removable display memory or opt for continuous measurement and unlimited recording via an external power supply with AC adaptor.
Save time and simplify your decontamination procedures with the NSN3's detachable display. Only decontamination of this removable accessory is required before leaving the controlled area.


Choose reliability with high accuracy measurements and data collectionCHOOSE RELIABILITY WITH HIGH-ACCURACY NEUTRON MEASUREMENTS AND DATA COLLECTION

The high sensitivity of the portable survey meter provides reliable, fast response time, accurate measurements over the energy range from thermal and fast neutrons (0.025 eV to 15 MeV).
It has excellent gamma rejection.
This performance is comparable to that of a transportable device (with a heavy moderator like Ludlum model). 

The dose rate measurement range extends from 0.01μSv/hr to 99.99 mSv/hr with an accuracy of ≤ ±20% at 10 μSv/hr.
The dose measurement range extends from 0.01μSv to 99.99 mSv with an accuracy of ≤ ±20% to 1 μSv.

Be confident in your measurements: the NSN3 survey meter is approved by CTHIR to IEC610005 edition 3, 2014.


Make it easy to retrieve the data collected   

The neutron dose survey meter is equipped with a USB port to display and share collected data on a PC. 


Applications and fields of use of the neutron survey meter

Applications and fields of use of the neutron survey meter

The neutron dose survey meter is designed for:

  • Radiation protection of workers exposed to radiation,
  • The search for neutron sources or the presence of radionuclides,
  • Detection and monitoring of radiological contamination,

It is perfectly adapted to the requirements and applications of:

  • Nuclear power plants,
  • Synchrotrons, particle accelerators,
  • Fusion reactors,
  • Experimental reactors,
  • Particle physics laboratories,
  • Decommissioning activities
  • Spent fuel processing and transport facilities
  • Civil security: protection of first responders
  • Industrial activities and non-destructive testing



Specification of the neutron dose survey meter 


StandardCompliant with IEC61005 ( 2003 ) and JIS 24341 ( 2006 )
Radiation measuredNeutron H * ( 10 )
DetectorProportional gas sensor
Measurement rangeDose rate : 0.01 µSv / h to 99.99 mSv / h
Dose : 0.01 μSv to 99.99 mSv
AccuracyDose rate : ≤ ± 20 % at 10 µSv / h
Dose : ≤ ± 20 % at 1 µSv / h
Energy range0.025 eV to 15 MeV
Energy dependenceICRP74 compliant ( H * ( 10 ) energy response curve )
Angular dependence≤ ± 25 % ( + 90 ° from the standard direction )
Linearity≤ ± 20 % reference ( 10 µSv / h )
Gamma ray sensitivity and gas detector sensitivity± 1 % of reading ( 10 mSv / h )
LCD DisplayFive digit display ( dose rate, accumulated dose )
CommunicationUSB cable or PC software 
Data storageDose rate , accumulated dose , history , data configuration .
Power supplyPrimary or secondary battery (6 x AA type batteries)
or AC adapter (100 to 240 Vac)
Battery lifeUp to 30 hours (without permanent display)
Operating temperature-10° C to 45° C
Operating humidity35 to 90 % RH ( non - condensing )
Dimensions289.5 ( W ) x 164 ( D ) x 246 ( H ) mm
Weight Approx. 3 kg


Neutron Survey Meter documentation