The ANTECH Neutron Coincidence Collars (NCC) are used by safeguards inspectors to verify the fissile material content of fresh nuclear fuel assemblies

ANTECH Neutron Coincidence Collars include:

            1. The N2023-M, designed for BWR fuel assemblies,
            2. The N2044, designed for PWR and smaller fuel assemblies,
            3. The N2071, designed for PWR and smaller fuel assemblies,


  • 23 highly moderated ³He neutron detectors to maximise efficiency
  • 1 holder is provided for americium/lithium source for active measurements; source holder assembly is easily removable
  • Non-interchangeable connector types prevent misconnection
  • Instrument can be used with an ANTECH model N2000 UNC, or an ANTECH Model N2000-2 Unattended Monitor or JSR-15 Neutron Coincidence Counter with INCC-32 Software
  • Mobile cart provides mounting platform and folds flat for transportation
  • Spares and tool kit available


  • Chamber can be configured for the passive measurement of plutonium content in MOX fuel assemblies and active measurement of Boiling Water Reactor (BWR) fuel assemblies
  • 3 detector panels and one moderator panel housing the interrogation source
  • 1 set of easily removable cadmium moderator panels, 0.50 mm (0.019 in) thickness. They are also available in the following configurations, 0.30 mm (0.011 in), and 0.35 mm (0.013 in) thicknesses
  • Junction box providing a high voltage (HV) connection to ³He detectors and low voltage (LV) and signal connections to Amptek A111 amplifiers. The door panel has two A111 amplifier units, and each side has one A111 amplifier
  • Junction boxes/amplifiers are “daisy chained” together to provide a single signal output to ANTECH Model N2000 Universal Neutron Counter (UNC), ANTECH Model N2000-2 Unattended Monitor or JSR-15.
  • 1 TTL output channel (SIGNAL) when used in 'OR' counting mode
  • Hinged door to facilitate quick loading
  • Description

    The ANTECH N2023-M and N2044 are high efficiency neutron detectors used for verifying 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. The N2023-M is used in Boiling Water Reactor (BWR) nuclear fuel assemblies, the N2044 is used in both Pressurised Water Reactors (PWR) and BWR fuel assemblies.

    The N2023-M is similar in specification to the N2044. Both units employ the classic ‘collar’ geometry and are designed for non-active measurements. They are supplied with the following components: coincidence collar assembly, cadmium curtains, interrogation source holders, interconnection cables, cart and transportation cases.

  • Specifications

    510 mm x 410 mm x 355 mm
    (including connectors)
    Outer dimensions (H x W x D)
    BWR fuel assemblies
    165 mm x 165 mm 6.5 in x 6.5 in
    37.5 kg (with 0.5 mm cadmium curtains fitted) Maximum weight (excluding trolley)
    Trolley Weight
    15 kg
    Low Voltage
    5V DC ± 10% Power to Junction Boxes/Amplifiers
    Input Power
    LV -5VA Maximum Power
    Maximum High Voltage
    HV - 1.8 kV
    Detection Efficiency
    With Cd = 17%

    Without Cd = 19.5%
    Die Away Time
    With Cd = 40 μs

    Without Cd = 45 μs
    Output Pulse Width
    50 ns ± 5 ns nanoseconds
    5 x 10⁴ electrons (nominal)
    Period between consecutive pulses
    500 ns nanoseconds
    Junction Box IP Rating
    IP65 Ingress Protection
    Temperature Range
    Operation = 5°C - 40°C, 20% to 95% RH

    Storage = 0°C - 60°C, 20% to 95% RH
    RH = Relative Humidity
    Complies with 2004/108/EC