ANTECH portal monitors are available in two basic configurations, Gamma ray measur-

ing based on the use of sensitive plastic scintilator detectors and combined gamma ray

and neutron measuring, again using sensitive plastic scintilators but combined with high-

pressure He-3 detectors.  The portal monitors are designed to detect radioactive materi-

als and, with neutron detection capability, to detect the presence of plutonium by passive

neutron counting. The shielded and collimated plastic scintilator detectors use low noise

photo multiplier tubes, with state of the art digital detection electronics based on ORTEC

digiBASE.  In the case of combined technology portals, the polyethylene moderated,

high-pressure He-3 detector tubes, providing enhanced neutron detection sensitivity, are

connected to high-speed charge collection electronics and operate in neutron totals count-

ing mode.

ANTECH portal monitoring technology is derived from work performed at the Los Ala-

mos National Laboratory (LANL) and implemented in the late 1980's by Jomar Systems.

Since the transfer of technology to ANTECH, extensive improvements have been added

and the ANTECH portal monitoring technology represents the current state of the art.

ANTECH continues to work with technology developers at Los Alamos who are engaged

in a process of continuing improvement with a view to optimising the performance for

Homeland Security and defence related applications.

The operation of ANTECH portal monitors is automated through the use of an onboard

microprocessor controller, which performs system diagnostic testing, input monitoring

and background discrimination. The controller employs algorithms based on the sequen-

tial probability ratio (SPR) test, developed originally by Fehlau and others at LANL.

The portals contain all the necessary electronics, including controller, power supplies,

amplification, single channel analyser and high voltage bias supplies to constitute stand

alone instruments.

The Series 5123 gamma ray and the Series 5125 combined technology gamma ray and

neutron Vehicle Portal Monitors are available in the standard configuration shown with

vertical pillars or with additional overhead and potentially under road additional sensors

for enhanced efficiency. They can operate in either continuous pass through or hold and

measure mode, depending on the application and sensitivity requirement. These Vehicle

Portal Monitors comply with the requirements of ASTM C1112-93 and are consistent

with the performance evaluation requirements of ASTM CI 1236-93.

·

(L

x W x H):

950mm x 400mm x 3020mm (each pillar)

·

·

8 - 10 grams total Pu (military grade)

approximately 1 kg highly enriched U