Significance and Use
4.1 This practice provides a means to compare DDAs on a common set of technical measurements, realizing that in practice, adjustments can be made to achieve similar results even with disparate DDAs, given geometric magnification, or other industrial radiologic settings that may compensate for one shortcoming of a device.
4.2 A user should understand the definitions and corresponding performance parameters used in this practice in order to make an informed decision on how a given DDA can be used in the target application.
4.3 The factors that will be evaluated for each DDA are: interpolated basic spatial resolution (iSRbdetector), efficiency (normalized Detector SNR (SNRN) at 1 mGy, for different energies and beam qualities), achievable contrast sensitivity (CSa), specific material thickness range (SMTR) and ISO-MTL , image lag, burn-in, bad pixels distribution and statistics and internal scatter ratio (ISR).
4.4 Given that each of these parameters are discussed together in many of the following sections, the following list will be helpful in selecting the key sections for a given test as follows. It should be noted that other sections of the document are needed to establish the appropriate technique for the parameter under test. Note that for each parameter (test), the first section listed is typically an apparatus or gauge (if required), the second section listed are the standardized measurements, and the third section listed involves the analysis or computations:
4.4.1 For iSRbdetector, see 5.1, 7.7, 8.2.
4.4.2 For Detector Efficiency, see 5.3, 7.8, 8.3.
4.4.3 For CSa, see 5.2, 7.9, 8.4.
4.4.4 For SMTR, see 5.2 (or 7.9, if already completed), 7.10, 8.5.
4.4.5 For ISO-MTL, see 5.2 (or 7.9, if already completed), 7.10, 8.6.
4.4.6 For Image Lag, see 7.11.1, 8.7.1.
4.4.7 For Burn-in, see 5.4, 7.11.2, 8.7.2.
4.4.8 For Bad Pixel Tests, see 6.2, 7.12, 8.8.
4.4.9 For ISR, see 5.4, 7.13, 8.9.
Scope
1.1 This practice describes the evaluation of Digital Detector Arrays (DDAs), and assures that one common standard exists for quantitative comparison of DDAs so that an appropriate DDA is selected to meet NDT requirements.
1.2 This practice is intended for use by manufacturers or integrators of DDAs to provide quantitative results of DDA characteristics for NDT user or purchaser consumption. Some of these tests require specialized test phantoms to assure consistency among results among suppliers or manufacturers. These tests are not intended for users to complete, nor are they intended for long term stability tracking and lifetime measurements. However, they may be used for this purpose, if so desired.
Note 1: Further information on application of DDAs is contained in Guide E2736 and Practices E2698 and E2737.
1.3 The results reported based on this practice should be based on a group of at least three individual detectors for a particular model number.
1.4 Units—The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
