The ANTECH Universal Neutron Counter Series 2000 combines in a single instrument Total Neutron Counting,

Shift Register Coincidence Counting, Multiplicity Counting and List Mode (LM) data acquisition. These counting

methods address most of the neutron counting requirements for today and the near future. With this new Virtual

Instrument (VI) it is not necessary to make the choice of using either neutron multiplicity counting or list mode

pulse acquisition for a safeguards inspection in the field. It combines the benefits of both measurement techniques:

immediate measurement results are provided by the Virtual Instrument (VI) real-time software, while the time

stamping information saved on a hard disk can be re-analyzed as necessity. For instance, the acquired pulse train

could be analyzed with future techniques or improved instrument parameters. Or one could exclude a noisy channel

from a data re-analysis.

The portable unit has enough inputs (max. 25), at least one per amplifier board for the small to medium neutron

detector systems. The use of Low Voltage Differential Signaling (LVDS) with twisted wire ribbon cable provides

an effective solution for sending pulses from amplifier board outputs to instrument inputs. A single D-sub connec-

tor provides signal and 5V 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. Upgrading, for instance, a standard

AWCC with LVDS signaling, not only reduces system dead-time dramatically, but also improves detection of

faulty amplifiers or counter 3He tubes. A cable testing feature provides a way to check the cable integrity and also

provides a rudimentary, anti-tampering measure.

The four BNC inputs on the front panel are intended for compatibility with today's single TTL output neutron

counting systems. When these systems are equipped with a de-randomizing buffer, the output signal will consist of

short pulse trains with a 20 MHz frequency. For this purpose the BNC inputs allow up to 3 pulses per acquisition

interval of 50 ns, preventing the loss of pulses. The four inputs allow connection to all the detector banks of a pas-

sive Neutron Coincidence Collar with standard coax cables.

Besides List Mode and Virtual Instrument acquisitions (neutron coincidence and neutron multiplicity), which can

be enabled or disabled by the user, a third acquisition, i.e. Totals Counting acquisition, is running in the back-

ground. Each input is equipped with a 32 bit totals scaler that is read out at a rate of 100 Hz. Totals Counting acqui-

sition can be used for flashing virtual LEDs on a PC screen or for anomaly detection while a measurement is in

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Maximum input count rate is 60 MHz for BNC/TTL and Lemo-S00/LVDS inputs

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Maximum input count rate is 20 MHz for D-sub/LVDS inputs

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Minimum input pulse width is 10 ns

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Maximum input continuous count rate 140 MHz

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USB bus powered (5V, 0.5A)

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System clock 20 MHz (time stamping resolution 50 ns)

High Voltage output, SHV connector, 2047 V, 30 mA max

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Very reliable high voltage module according to MIL-HDBR-217F, Notice 2

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Requires USB 2.0 interface and medium level PC (Very high LM rates require disk drives

with SATA-II interfaces for increased performance)

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32 bit totals scaler on each input

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LED displays for pulses present on BNC inputs only, Virtual LED displays for pulses present on all in-

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Size 129 mm x 156 mm x 53 cm (w x l x h) (includes front and rear panel connectors), Weight 500 g