In the ultrasonic community there is a growing use of models to simulate inspection processes [1,2]. One necessary input to such models is knowledge of the transducer’s radiation pattern. The radiation pattern of a commercial transducer often approximates that of an ideal, focused, piston transducer with appropriately chosen parameters (element dimensions and focal lengths), and these“ideal probe” parameters often serve as model inputs. In this paper we demonstrate beam mapping methods for determining these parameters. For probes with circularly symmetric beam cross-sections, an axial scan of the beam suffices. For more general probes, C-scan data are acquired to map out the beam cross section at several different waterpaths. In each case, the transducer parameters are determined by adjusting their values to minimize the discrepancy between the measured and model amplitudes. A technique for handling misaligned data is also described. Measured and fitted fields are compared for a variety of transducers (spherically, cylindrically, and bi-cylindrically focused) including one with a presumably damaged element. In addition, the axial scan and C-scan methods are compared for one circular, spherically-focused transducer.
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