Gamma Spectrometry

High Resolution Gamma Spectrometry (HRGS) 


IRAS Active Analytics operate five high purity germanium detectors for laboratory work.  The performance characteristics are matched to the application, to optimise delivery of customers’ requirements.  

For example, we operate a 65% relative efficiency n-type for environmental and Out of Scope analysis.  Such a detector is capable of delivering demanding limits of detection even at low energies. 

We operate a 25% relative efficiency n-type for active samples, utilising the lower efficiency to avoid count rate / dead time issues whilst maintaining a sample stand-off distance which still permits it to be analysed within the shield. 

With a significant investment in the latest technology in electrical cooling (Ortec ICS-4) and digital signal processing, the high performance and reliability is achieved to support our customers projects. 


IAA use both conventional and mathematical calibrations all based on traceable reference materials, to cover a comprehensive range of geometries, detector stand-offs and matrix density / elemental composition.  Reproducible positioning of calibration sources and samples is achieved using jigs, manufactured by our in-house engineering team.  These incorporate carbon fibre protection for the beryllium windows on our n-type detectors. 

Low Resolution Gamma Spectrometry (LRGS) 

IRAS Active Analytics also operate a wide range of LRGS detectors, specifically tailored for applications, whether that be thin crystal detectors for plutonium assay or wide area land surveys utilising some of the largest NaI(Tl) detectors in the UK.