The ANTECH 3700-600 is a modular assay solution for the segregation of gamma-

emitting waste in large containers. The principle of the measuring system is that of mak-

ing possible the taking of multiple measurements of the same container from different

measuring points thereby obtaining multiple estimates for the activity which is inside.

These results (after correction for geometry and attenuation) may then be combined to

produce a best estimate of the container total activity. `Outliers' from the container aver-

age are pointers to inconsistencies which lie in either matrix or source distribution inho-

In operation, the container passes past the detector measurement station and stops at mul-

tiple measurement points, for example 25%, 50% and 75% of the length of the container.

At each point, the multiple collimated HPGe detectors perform multiple simultaneous

measurements. In a typical configuration, four detectors are positioned on each side of the

measurement station, resulting in this example, in 12 assay measurements for the con-

ISOTOPIC V3.0 , the latest waste-assay software from ORTEC manages the gathering of

the multiple detector spectra and processes the result. Each detector to be used in the as-

say is calibrated with a simple multi-nuclide point source, and the program then extrapo-

lates the calibration to the actual geometry and matrix conditions present at each meas-

urement point. The results from each detector are then averaged and stored within an in-

dustry standard data base. A separate ISOTOPIC V 3.0 data sheet describes the software

in more detail.

The modular nature of the 3700-600, means that for easier or for more difficult measure-

ment situations, fewer detectors or extra detectors may be used. The beauty of the ap-

proach lies in the fact that STANDARD HPGe detectors, calibrated via simple point

sources and with collimators of know dimension and materials are all that is required.

This has great benefits in the cost of ownership. Replacement detectors if needed can be

brought into use in minutes. The fact that ISOTOPIC calculates a complete container as-

say based on container physical parameters and a point source calibration for each detec-

tor , means that loss of one detector is not catastrophic to all measurement ability, and

moreover that addition of a detector can be achieved in minutes.

Assay Accuracy:-

This is largely dependent on the distribution of sources inside the container and the num-

ber of measurement points, but 25-65% could be considered typical

Measurement times:-

The same considerations apply. Also, Isotopic V3.0 allows measurements to be made si-

multaneously or sequentially. For the example above, using 4 detectors, 2 each side of the

measurement point, 3 15-minute measurements would be typical, making an over all

measurement time of 45 minutes

Each standard spectroscopy sub-system (typically 4) comprises the following

·  ORTEC PROFILE Series GEM HPGE detector with SMART-1 electronic package

·  X-Cooler non-LN2 HPGe detector cooling