All Olympus phased array probes are rigorously tested to ensure conformance to the highest standards. An extensive database, containing characterization records for each probe sold, is maintained by Olympus NDT. This information can be accessed to compare probe properties.
If you have any special testing requirements, please contact Olympus NDT.
A Probe Test Data Sheet is supplied with the purchase of any probe. This form presents the following information:
The median waveform graph displays a median pulse-echo response (typical) from the test target. Half of the return pulses from the probe elements will have a peak-peak voltage greater than (or equal to) this median element, and the other half will have a smaller value. Return pulse duration is shown on the horizontal axis (in microseconds) and amplitude is shown on the vertical axis (in V). The number of the median element is shown above the graph (in parentheses).
Median Waveform FFT
The median waveform FFT graph shows the calculated spectrum for the median waveform (see above) over a range of zero MHz to twice the probe's nominal frequency.
-6dB Center Frequency
The -6dB center frequency bar graph displays a calculated center frequency value for each of the probe's elements. This value is calculated by using the halfway point (in frequency) of an imaginary line intersecting a given element's spectrum (FFT) data at the -6db level. The average value of all the probe's elements is displayed at the top of the graph.
-6dB Percent Bandwidth
The -6dB percent bandwidth bar graph displays a calculated percent bandwidth value for each of the probe's elements. This value is determined by using the length (in frequency) of an imaginary line intersecting a given element's spectrum (FFT) data at the -6db level and calculated as a percentage of the center frequency. The average value of all the probe's elements is displayed at the top of the graph.
The peak-to-peak sensitivity bar graph displays a value for each of the probe's elements, representing the sensitivity of the probe. This value is calculated by using the magnitude of the excitation (test) pulse sent to each element and the peak-to-peak voltage measurement of that element's pulse-echo return (from the test target). The reported value is -20 multiplied by the log of the ratio of these two magnitudes. The average value of all the probe's elements is displayed at the top of the graph.
The various pulse-width bar graphs display values representing the axial resolution of the elements' pulse-echo returns at various levels, such as -20 dB, -30 dB and -40 dB. These values are calculated by measuring the return pulse's width (in nanoseconds) at the desired level. Axial resolution is an important measure of the ability to distinguish individual pulse returns from one another during normal probe operation. The average value of all the probe's elements is displayed at the top of the graph.
A Wedge Specification Sheet is provided with every wedge. This sheet presents the wedge offset parameters of a phased array probe's first element for both OmniScan and TomoView software. It is important to note that the values given are only applicable for the wedge and probe combinations listed.