Performance evaluation of a photon counting detector for high energy NDT applications

Peterzol, Angela; FRAMATOME / INTERCONTROLE; France

Brun, P.; AREVA/Intercontrôle; France
Eriksson, C.; Direct Conversion / XCounter AB; Sweden
Ullberg, C.; Direct Conversion / XCounter AB; Sweden

ID: ECNDT-0309-2018
Download: PDF
Session: X-ray radiography 2
Room: G3
Date: 2018-06-11
Time: 15:20 - 15:40

The use of digital detectors as an alternative of film radiography is still an open issue in NDT community. The application of Digital Detectors Arrays (DDA), such as Flat Panel Detectors (FPD), was supported by ASTM (2010) and CEN (2013). More specifically, the EN ISO 17636_2 standard treats both computed radiography and DDA usage for NDT of welds.
In this paper, we present image quality assessment of a photon-counting detector (PCD), which operates in the direct x-ray converting mode; and it was designed using latest CdTe-CMOS sensor hybrids. The pixel size is of 100µm, which makes the PCD suitable for controlling parts with thickness > 40mm (class B). An important characteristic concerns the sensor thickness: 2mm of CdTe. This value permits increasing quantum efficiency of about a factor five in respect to FPD based on GOS scintillator (200µm thick). The PCD was investigated with an Iridium 192 and Cobalt 60 gamma sources; and with a linear accelerator (6MeV). Image quality has been assessed in terms of EN ISO 19232 IQI (wire and hole). In addition, also the Signal to Noise Ratio and the basic spatial resolution (via the duplex IQI) have been measured according to the EN ISO 17636_2. For the Iridium 192 gamma source, performance evaluation has been completed by means of a qualification mock-up containing artificial flaws. A comparison with film radiography will be also presented.