High Performance CZT Detectors for In-Line Non-destructive X-Ray Based Density Measurements

Abstract

We have developed a system for in-line density measurements based on a CdZnTe (CZT) detector to be used for quality control purposes related to production inspection, failure analysis, and lot inspection for wood-based panel industry. Real-time absolute density measurement systems are fundamental to minimize production wastage, especially for continuous production as wood and ceramics.CZT detectors with dimensions 4.1 x 4.1 x 2.5 mm3 were realized starting from standard Redlen Technologies CZT material by due2lab s.r.l. in collaboration with IMEM-CNR and integrated in a stand-alone detection module fully engineered and realized by due2lab. Low dark current density (10÷100 pA/mm2 @100 V/mm) even at high bias voltages (up to 1000 V) at room temperature (T = 25 °C) has been reproducibly achieved in several samples. These low dark current values are crucial in non-destructive X-ray industrial applications where X-ray photons in the low energy range play an important role in material discrimination. Digitalization of the CZT sensor signal was obtained with a novel digital electronic board designed by due2lab. The spectra obtained by irradiating the detectors with a 241Am source show excellent resolution down to 12 keV. The detectors were integrated in an innovative in-line non-destructive X-ray density measurements system for wood panel production quality control developed by IMAL PAL s.r.l. (Modena, Italy).