PCS-Enabled Radiation Monitor (PERM)

PSI's PERM Gamma Detector

The PERM gamma detector uses a low-cost 2 in x 4 in x 16 in NaI(Tl) crystal, enclosed in an IP67-rated housing, as the scintillation material. The crystal/photomultiplier tube (PMT) package is a commercial item supplied by St. Gobain. The design associated with the packaging of the COTS scintillator is driven by the need to provide medium-resolution (~8%) gamma spectra (30 – 3000 keV) with accurate and stable energy calibration. When combined with our custom Thermal Management Unit (TMU) and the built-in software stabilization algorithm, the PERM provides automatic, source-less gain stabilization over the entire operational temperature range of -30°C to 55°C. The result is extremely high-quality spectra with less than 1% variation in the energy calibration stability. Extensive field operations in changing environmental conditions such as in maritime ports, desert environments, and as gantry installations over highways have demonstrated that the PERM achieves ~ 0.5% absolute energy calibration uncertainty with < 0.5% instability. This level of calibration stability and accuracy maximizes the performance of our proven Poisson Clutter Split (PCS) algorithm.

PERM Gamma Detector
PSI's PERM Gamma Detector

The PCS algorithm processes energy spectra and performs clutter suppression, yielding de-noised gamma-ray spectra that enable significant enhancements in detection and identification of low activity, unshielded, shielded, and masked threats with spectral target recognition algorithms. PCS is optimized for larger volume detectors like the PERM but also offers key advantages when integrated with smaller handheld devices such as RIIDs and SPRDs. For example, PCS is the detection and identification algorithm operating on the Kromek D3S-ID detector and provides real-time (1 Hz) isotope ID, enhanced sensitivity and a significant reduction in operational false alarm rates. For more information on the D3S detector, please refer to a Popular Mechanics article: “This Tiny Device Can Detect Nuclear Armageddon” by Dan Dubno, April 25 2019 (https://www.popularmechanics.com/technology/security/a27006059/nuclear-kromek-d3s/).

A PERM-S variant is available and comes equipped with a communication module that establishes a direct interface between the system and any large distributed sensor network, such as SIGMA (http://www.psicorp.com/content/psis-advanced-sensor-methods-and-technology). GPS data and cellular connectivity are integrated as part of the communication module.

PERM and PURDAAS R/N source detection, ID and contextual capability

The PERM can be used as a standalone detector mounted directly to existing infrastructure or as part of other systems. Several application examples include:

  • Lamp posts/stands at choke points or urban intersections
  • In vehicles for mobile applications
  • On boats for maritime applications

  • Equipped with the PCS-Enabled Unattended Radiation Detection and Automated Attribution System (PURDAAS) package that provides contextual data for improved environment visualization (future upgrade available in 2020). PURDAAS is a contextual system that is interfaced with a PERM detector to provide real time detection, identification and improved awareness of radiological and nuclear threats. The system offers actionable intelligence to interdict the source.

Request the PERM brochure and technical specifications