Introduction

04 Universal Neutron Counter, N2000 Series

The ANTECH Universal Neutron Counter N2000 has been designed to provide a state of the art neutron counting capability for nuclear safeguards, waste assay and accounting measurements for special nuclear materials. The unit incorporates total neutron counting, shift register neutron coincidence counting, neutron multiplicity counting, and list mode neutron data acquisition. It is compatible with all ANTECH neutron counting instruments and it can be employed  to upgrade the electronic counting and data acquisition component of most neutron measurement systems used for safeguards and waste assay.

The ANTECH N2000 can be deployed in a variety of configurations including rack mounting and it can be integrated into existing systems as an upgrade providing enhanced neutron counting capability. The neutron data generated by the unit is compatible with most neutron counting and analysis software codes.

DS.N2000-UNC.2.1.A4

Description

The ANTECH Universal Neutron Counter 2000 Series combines Total Neutron Counting, Shift Register Coincidence Counting, Multiplicity Counting and List Mode (LM) data acquisition in a single portable package to provide a state of the art instrument. With this new Virtual Instrument (VI) it is not necessary to choose between neutron multiplicity counting or list mode pulse acquisition for a safeguards inspection in the field. The 2000 Series combines the benefits of both measurement techniques; immediate measurement results are provided by the Virtual Instrument (VI) real-time soft-ware, while the time stamping information saved on a hard disk can be re-analysed as necessary. The acquired pulse train can be analysed with future techniques or improved instrument parameters.
The unit has a maximum of 19 inputs, which provide at least one input per amplifier board for the small to medium de-tector systems. The use of Low Voltage Differential Signaling (LVDS) with twisted wire ribbon cable (a round shielded cable is also available) provides an effective solution for sending pulses from amplifier board outputs to instrument in-puts. A single D-sub connector provides signal and 5Vdc power supply connections. For this purpose a special interface board must be embedded in the junction box of a neutron detector for TTL to LVDS level conversion. For example, up-grading a standard Active Well Coincidence Counter with LVDS signaling dramatically reduces system dead-time and improves the detection of faulty amplifiers or counter 3He tubes. A cable testing feature makes it possible to check the integrity of the cable and is a rudimentary anti-tampering measure.
The four BNC inputs on the front panel are compatible with current single TTL output neutron counting systems. These inputs allow up to 3 pulses per acquisition interval of 70 ns, preventing the loss of pulses, and enable connection for up to four detector banks or amplifier arrays of a Passive Neutron Coincidence Counter.
Besides List Mode and Virtual Instrument acquisitions (neutron coincidence and neutron multiplicity), which can be ena-bled or disabled by the user, a third acquisition, i.e. Totals counting is running in the background.
Each input is equipped with a 32 bit totals scaler that is read out at a rate of 100 Hz. Totals Counting acquisition can be used for flashing virtual LEDs on a PC screen or for anomaly detection .
The unit also has a ‘Synch In’ LEMO connector to combine multi-ple units in a single multiplicity counter in case more inputs are required. This input can also be used to trigger an acquisition, at a sufficiently high rate for Differential Die-away Techniques (DDT) with pulsed neutron generators (Up to 100 Hz rate).

Features & Benefits

Features

  • High frequency 20 MHz acquisition clock for improved accuracy and backward compatibility with older systems that use 4MHz clocks
  • Very high count rates inputs: 4TTL (BNC) — up to 60MHz
  • High count rates inputs: 15 LVDS (D-sub connector) — 20 MHz
  • Proprietary data compression technique for time stamping information allowing very high count rates while minimising disk space requirements
  • High Voltage supply for ³He neutron detectors—max 2000 Vdc
  • Low voltage 5 Vdc supply for a maximum of 8 amplifier boards via front-panel BNC connector
  • Count Gate Out connector (LEMO S0) to signal when the unit is effectively counting (used for synchronizing multiple units)
  • I/O connector (LEMO S00) can be defined by user to be an input or an output. When used as an input it can be used to start/stop an acquisition. When configured as an output it may be used to signal the end of a measurement or to trigger an alarm (for instance when a certain count rate occurs)
  • The operator can select which inputs contribute to the coincidence count and which don’t. All inputs also function as a scaler (a simple pulse counter)
  • Each input has an input inhibit function. When enabled, input is disabled for a fixed time

Benefits

  • Simultaneous neutron totals, coincidence, multiplicity counting and list mode (time stamping) acquisition
  • Compact portable design
  • Virtual Instrument design: various pulse train analysis techniques are possible with real-time software
  • Fully compatible with INCC and ANTECH MasterPassiveActive software
  • Reduction of system dead-time through embedded pulse mixer with multiple inputs (software controllable enable/disable): 4 TTL and up to 15 LVDS
  • Powered via 12 Vdc mains adaptor

 

 

Specification
Dimensions (H x W x D) 53 x 129 mm x 156 mm (includes front and rear panel connectors)
Weight  476g
Temperature range Operation 5°C to 40°C (up to 90% RH)
Storage 0°C to 50°C  (up to 90% RH)
Input power 12 Vdc, 0.5 A
Output power LV 5 Vdc, 1.0A maximum
HV 2000 Vdc, 100 μA maximum
Safety EN60601-1
EMC Complies with 2004/108/EC
Maximum input count rate 60 MHz for BNC/TTL inputs
20 MHz for D-sub/LVDS inputs
Minimum input pulse width 70 ns
System clock  20 MHz (time stamping resolution 50 ns)
Interfaces USB 2.0
Scaler 32 bit totals on each input
Inputs BNC 4 BNC (LED pulse indicators for each channel)
LVDS 15 (D sub-connector)