Bladewerx - Model SabreASM -Alpha Survey Meter

SabreASM consists of a fiberglass enclosure with large-area color touchscreen, three control buttons, a red/green light stack with audible alarm, and carrying handle, and encloses a battery, processor board, and multi-channel analyzer.  A six foot cable connects the the instrument to the detector probe which houses the solid-state detector and preamp, protected by a high-percentage open area screen.  Unscrewing and opening the hinged front lid provides easy access to all the internal components.  The SabreASM is designed for 8 hours of field survey use off the internal battery, or can be operated continuously off the included AC Adapter/charger.

Alpha-Peak Shape Fitting

A state-of-the-art peak shape fitting algorithm is used to fit the alpha spectrum data and to model each of the radon progeny plus up to two user-defined regions-of-interest or isotopes-of-interest.   Alpha peak shape fitting is a technique that uses the profile of an alpha isotope peak to create a composite curve of multiple peaks which best fit the actual spectrum.  Because the individual nuclide peaks are independently determined, the separation of nuclides is not impacted by the radon equilibrium state or peak ratio changes during the decay process.  Precise fitting of the 6 MeV peak tail results in allows accurate subtraction of radon progeny counts from the energy region below 5.5 MeV.  ROIs can be specified from 0 to 5.8 MeV.

The SabreASM default mode uses one user-defined Region-of-Interest (ROI) from 2 to 5.5 MeV.  The software fits the radon peaks and the counts under the fitted curve–within the region–are subtracted from the total ROI counts.

Every survey count is assigned a unique Survey ID.  During the count, a recording of the counts is saved, listing the count channel and time received, and saved in a replay file associated with the ID.  Any survey count can be replayed later simply by selecting the file to be replayed by its Survey ID. In addition, the SabreASM software creates a database of the results of each user-initiated count—whether the count completed normally, was cancelled, or finished with an activity above the action level.  The database uses the comma-separated- variable (*.csv) format, recognized by most spreadsheet and database software. Alpha spectrums from a count, along with the fitted curve, can also be saved for later examination.

Display and Control The integrated SabreASM analysis and control software is a Microsoft® Windows-based application that provides complete instrument control, calibration, data analysis, and data logging capabilities.  A 5.8-inch diagonal VGA-resolution (640 x 480) color display and touchscreen provides for a clear and intuitive user interface.  Spectrum analysis and subtraction of radon and thoron decay product interference is possible through the use of the well-proven Bladewerx alpha peak-shape fitting algorithm.  For simplified energy calibration, the user interface employs simple hold and drag operations to position peak locators on the spectral display.  An important labor-saving feature is the minimum count time mode where—based on user-defined action level and confidence bounds—the instrument sample count is terminated as soon as the user-defined constraints are met by the counting statistics.