The technique is applicable to the measurement of activity from extremely low levels to extremely high levels and across a large range of densities. It is capable of measuring waste in a variety of matrices and chemical forms and is particularly applicable when the chemical form and the relationship between the nuclide and matrix are unknown.
As in the standard Segmented Gamma Scanner (SGS), the drum or sample is rotated about its vertical axis as horizontal segments are scanned. This allows for any inconsistencies in the matrix density whilst building a vertical profile of gamma ray transmission and nuclide concentration.
The ANTECH G3250-220 is the first system to utilise both the storage of the transmission source within a tungsten shielded safe and a fully automated variable collimator aperture. The variable aperture collimator greatly increases the range of activity that can be assayed on one measurement system without the need for any manual alteration.
Laser alignment during assembly and PLC motor control ensures optimum alignment of the transmission source and the detector once the source leaves the safe. When the transmission source is stored in the safe, there is typically a leakage of less than 5 μSv/hr near the surface of the safe. In the safe storage position the detector does not detect any gamma rays from the transmission source.
The ANTECH implementation of the wide range segmented gamma scanning technique in the Model G3250-220 complies with the Standard Test Method for Non-destructive Assay by Segmented Passive Gamma ray Scanning, ASTM number C1133-03.
J. A. Mason, M. R. Looman, R. A. Price, A. C. N. Towner, R. Kvarnström and H. Lampen, “Design and Operation of a Wide Range Segmented Gamma Ray Scanning Assay Instrument for the Measurement of both Low and Intermediate Level Waste”, Proceedings of INMM11, Palm Springs, CA, July 2011. (11-A-424-INMM)
John A. Mason, Marc R. Looman, Antony C. N. Towner, Kapila Fernando, Roland Wong, Robert A. Price, Bret Taylor and Paul Anderson, “Calibration and Validation of a Wide Range Segmented Gamma ray Scanning Instrument for the Measurement of Low and Intermediate Level Waste”, Proceedings of ICEM11, Reims, Champagne Congres, France, September 2011. (ICEM11-59304)
Ma13a J. A. Mason, M. R. Looman, L. V. Odell, A. J. Poundall, A. C. N. Towner, D. Hong, W. Jang, K. Kwak, S. Seo and M. Piotrowski, “Design and Testing of a Novel Wide Range – Segmented Gamma Scanner Incorporating Tomographic Gamma Scanning for Measuring both Low and Intermediate Level Waste in Drums-13470”, WM2013 Conference, February 24 – 28, 2013, Phoenix, Arizona, USA. (WM13-13470)
- Automated variable collimator aperture
- Safe storage of the transmission source when not in use
- Adjustable detector position for optimal measurement
- Multiple drum loading solutions available
- Optional built-in Geiger-Müller dose rate sensor
- Waste drum barcode recognition
- One or two pass measurement, emission and/ or transmission
- Remote operation
- Windows based menu driven software for ease of use
- Ability to detect both very low and very high activity gamma radiation on one measurement instrument
- Typical measurement time of 30 minutes although increased accuracy and precision can be achieved by extending the measurement time
- Non-destructive assay of up to a 200 litre drum with a 320 litre overpack drum option
- GammaScan SGS analysis complies with Standard Test Method for Non-destructive Assay by Segmented Passive Gamma Ray Scanning ASTM standard number C1133-0.3
|Dimensions (H x W x D)||2500 mm x 2900 mm x 1000† mm (98.43 in x 114.17 in x 39.37 in)†1700 mm (66.23 in) long conveyor illustrated in photo|
|Drum size||200 litre with 320 litre overpack|
|Variable collimator range||1 mm – 70 mm|
|Germanium coax detector efficiency||40% + typical (other detector efficiencies as an option)|
|Transmission source||152Eu (typical)|
|Detectable activity range||Up to 1012 Bq per drum|
|Density range||Up to 2000 kg/m3|
|Analysis software||Windows operating platform, GammaScan user interface|
|Digital MCA||ORTEC DSPEC Pro or DSPEC 50|
|Network connection||Ethernet or USB|