Neutron Coincidence Collar, N2044

The ANTECH N2044 Neutron Coincidence Collar (NCC) is used by safeguards inspectors to verify the fissile material content of fresh nuclear fuel assemblies.

It is a high efficiency neutron detector and is used to verify all types of un-irradiated light-water reactor fuel and fuel assemblies, notably LEU fuel, Mixed Oxide (MOX) fuel, fuels containing burnable poisons such as gadolinium, and other contemporary fuel and fuel assembly types.

It employs the classic “collar” geometry and is designed for non-active and active measurements.

Each unit is supplied with the following components: coincidence collar assembly, cadmium curtains, interrogation source holders, interconnection cables, cart and transportation cases.


N2044 Datasheet

Features & Benefits


  • Chamber can be configured for the passive measurement of plutonium content in MOX fuel assemblies and active measurement of 235U in Pressurised Water Reactor (PWR) and Boiling Water Reactor (BWR) fuel assemblies
  • 3 sets of easily removable cadmium moderator panels (for all slabs in all configurations); 0.30 mm (0.011 in), 0.35 mm (0.013), and 0.5 mm (0.019 in) thicknesses
  • Junction box with 2 amplifier units per panel provides a high voltage (HV) connection to 3He detectors and low voltage (LV) and signal connections to Amptek A111 amplifiers
  • Junction boxes/amplifiers are “daisy chained” together to provide a single signal output to JSR12 or AMSR
  • 1 TTL output channel (SIGNAL) when used in “OR” counting mode
  • Hinged door to facilitate quick loading


  • 44 highly moderated 3He neutron detectors to maximise efficiency for configuration
  • 2 holders are provided for americium/lithium sources for active measurements; source holder assemblies are easily removable
  • Non-interchangeable connector types prevent misconnection
  • Instrument can used with the an Advanced Multiplicity Shift Register (AMSR), JSR-12 or JSR-14 Neutron Coincidence Counter with INCC-32 Software
  • Mobile cart provides mounting platform and folds flat for transportation
  • Spares and tool kit available
Outer dimensions (H x W x D) 532 mm x 486 mm x 445 mm (including connectors) (20.59 in x 19.13 in x 17.52 in)
Inner dimensions compatible for following fuel assemblies (W x D) WWER 1000 234 mm x 270 mm (9.21 in x 10.63 in)
WWER 440 145 mm x 270 mm (9.21 in x 10.63 in)
PWR 230 mm x 230 mm (9.06 in x 9.06 in)
BWR 140 mm x 140 mm (5.51 in x 5.51 in)
Maximum weight 58 kg with 0.5 mm (0.019 in) Cd curtains fitted
Junction box IP rating IP65
Temperature range Operation 5°C – 40°C, 20% to 95% RH
Storage 0°C – 60°C, 20% to 95% RH
Power to junction boxes/amplifiers 5V DC ±10%
Safety Conforms to European Union Directive 200/95/EC (EN61010-1:2001)
EMC Complies with 2004/108/EC
Detection efficiency > 15% for the WWER-1000/PWR configuration
>20% for the WWER-440/BWR configuration
Die-away time 25μs (252Cf point source at centre of the cavity, 0.3mm [0.011 in]Cd curtains installed)
Maximum power LV – 5 VA
Maximum high voltage HV – 1.8 kV
Output pulse width 50 ns ± 5 ns
Sensitivity 5 x 104 electrons (nominal)
Period between consecutive pulses 500 ns