Features

• Processes 30-50 people per hour (depending upon computer)
• One minute count time for typical operation.
• 150 Bq (4 nCi) ⁶⁰Co LLD with person in shield.
• Vertical Linear Geometry for best accuracy.
• Two very large 7.6 x 12.7 x 40.6 cm (3 x 5 x 16 in.) NaI(Tl) Detectors.
• Shielded in all straight-line directions by 10 cm (4 in.) of low background steel.
• Modular shield construction for easy assembly.
• Rapid on-site analysis and presentation of results.
• Full spectroscopy; not just a screening counter.
• ABACOS family of software for flexibility and ease of operation.
• Extensive QA data collection program.

Description

The FASTSCAN whole body counter is designed to quickly and accurately monitor people for internal contamination of radionuclides with energies between 300 keV to 1.8 MeV. The FASTSCAN system uses large area sodium iodide detectors and CANBERRA's ABACOS and Genie Software to achieve low minimum detectable activities with count times as fast as one minute. It is intended for use in power plants and other facilities where the possible contamination spectra are well known and uncomplicated.

The system is as easy to use as today's digital cameras. The operator simply positions the person to be counted inside the shield and in front of the detectors, and then begins the count with the software. The software starts the count, completes the count, stores the data, displays the spectral data, performs the analysis and prints the report. The best part is that this system will be ready for operation as soon as the installation is completed.

CANBERRA's FASTSCAN System includes two large sodium iodide detectors (NaI(Tl)) 7.6 x 12.7 x 40.6 cm (3 x 5 x 16 in.) that typically provide a priori Lower Limit of Detection of approximately 150 Bq (4 nCi) for ⁶⁰Co with a count time of one minute for a normal person containing ⁴⁰K. The FASTSCAN's dual detector design provides uniform or flat (±15%) response along the longitudinal axis from the thyroid of the tallest 99th percentile male to the lower gastrointestinal tract of the shortest female.

The FASTSCAN uses a shadow shield to minimize spectral background interference.

This type of shield provides an optimal trade-off between shield size, weight and cost with background reduction for environments with slightly elevated background. The shield is constructed of 10 cm (4 in.) thick low background steel (2 in. in a few less critical areas).

Steel was chosen over lead because of its structural properties and because it doesn't contain ²²⁶Ra which is always present in lead. The low background steel is manufactured for CANBERRA using a special cobalt-free process. This special process guarantees that the steel will be free of the ⁶⁰Co contamination found in normal steel. The FASTSCAN's steel shield is covered with painted sheet metal and lined with molded plastic for ease of decontamination.

The FASTSCAN is designed to save facilities money in operation. It has no moving parts to minimize maintenance costs. The stand-up design also saves floor space and allows personnel to enter and exit the counter quickly and easily. The stand-up design also allows the use of front and backside counts to test for external contamination when a count result shows contamination.

The CANBERRA FASTSCAN Whole Body Counter is a turnkey system that includes all of the hardware, software and services needed for immediate operation. The FASTSCAN is factory integrated and calibrated before shipment. Once the system arrives at the customer's site it is installed by CANBERRA personnel or representatives and on-site training is provided.

System Operation

The subject enters the counting shield and leans against the back wall. There are molded positioning devices on the back wall that make it natural for the subject to stand in the correct location. The operator starts the count using the ABACOS software included with the system. The software starts the data collection and brings up a subject demographics screen. The operator fills in a brief demographics screen about the count (subject name, ID number, reason for count, etc.). The rest is completely automatic. The ABACOS software displays the spectral data during the acquisition. It stops the count when the pre-programmed count time has elapsed, it stores the data, analyzes the spectral data and reports the results. Once the reporting phase of the count is completed ABACOS automatically resets the system for the next count.