- A simple-to-use answer to the screening of foodstuffs for radioactive contamination, now further enhanced.
- Suitable for counting of a wide variety of sample types.
- Meets regulatory detection limit requirements:
- Clear results with calculations such as percentage of maximum permitted concentration (MPC).
- Immediate feedback with audible alarms to warn of sample activities that exceed a user-set percent of MPC limit.
- Ready for immediate use “out-of-the-box” including standard sample containers. Check sample included.
- Intuitive software for data collection, display, and storage.
- Transportable and easily deployed cart option.
- High efficiency counting and easy sample loading using 3” x 3” NaI detector in bench-top low background lead shield, optionally mounted on easy-to-maneuver wheeled cart .
- Simple setup with USB-connected ORTEC digiBASE all-in-one digital preamplifier and detector high voltage and powerful digital signal processing multichannel analyzer.
- Digitally stabilized against temperature variations.
The ORTEC FoodGuard-1 Foodstuffs Monitoring system can rapidly and accurately screen foodstuffs for the radionuclides expected from release events from nuclear power plants: for example 131
Cs and 137
Cs. Total Cesium (the sum of 134
Cs and 137
Cs activities) can also be reported. The system is battery operated, portable, and low power so it can be used where the foodstuffs are gathered, imported, sold or consumed. It is easily transportable and a cart mounted option allows the system to be used in places such as food markets where the system is easily brought to the product.
The FoodGuard-1 system hardware consists of a sodium iodide (NaI(Tl)) spectroscopic gamma-detector in a lead shield, an ORTEC digiBASE all-in-one spectrometer, a laptop PC and laser printer. The digiBASE supplies the multichannel analyzer function, the high voltage for the NaI detector, and all the signal processing electronics. Internal stabilization electronics and internal check source allow the system to be used over a wide range of environmental conditions.
Principle of Operation
Sample material is placed in a Marinelli beaker (supplied). The beaker is then placed on the detector in the shield. The operator starts the process using the FoodGuard software and is guided through a series of questions. The software collects the data, analyzes the spectrum, checks the results against allowable limits, and prints the report. The spectra and reports are also saved on the laptop hard disk. Samples that exceed defined limits are clearly marked on the report for quick results reporting that can easily be shared.
The spectrum analysis uses an "interference ROI matrix" method, approved by the US FDA for the monitoring of foodstuffs.
The matrix operations are based on Numerical Recipes.
The system is delivered pre-calibrated for gain and efficiency. The fixed efficiency calibration is pre-determined by the dimensions of the detector crystal and the sample containers used. Gain calibration is adjustable and once set is stabilized against temperature drift. Standard 1-liter Marinelli beaker containers are included with the system, and the factory calibration ensures accurate results if these containers are used. The naturally occurring isotope, 40
K, is also reported and can be used to monitor system performance as well as providing the reference peak for gain stabilization.
Lower MDC and Increased Customization with FoodGuard-2 HPGe System
FoodGuard-1 is designed for rapid analysis of the most common radionuclides expected from nuclear power plant events. For lower MDC, more advanced reports, and customizable nuclide libraries, ORTEC has developed the FoodGuard-2 High Resolution Germanium system.