NPL provides the calibration of the free-field sensitivity of miniature hydrophones of the type used to characterise medical ultrasonic fields. The service covers the frequency range 0.1 MHz to 60 MHz.
The service uses a comparison method where the response of the test hydrophone is compared against a reference transfer standard hydrophone, the calibration of which is traceable back to the NPL Primary Standard laser interferometer. Multiple frequency calibration techniques are based on non-linear distorted waves, which provide the sensitivity in multiple integers of the driving frequency and broadband pulses for a fine frequency calibration.
The following calibrations are available, please enquire for special requirements:
Magnitude calibration of a hydrophone over the frequency range 1 MHz to 40 MHz in 1 MHz increments; UKAS accredited and compliant with ISO 17025
Relative phase response calibration of a hydrophone over the frequency range 1 MHz to 40 MHz in 1 MHz increments
High frequency hydrophone calibration (Magnitude only) up to 60 MHz
Fine frequency calibration (Magnitude and phase) between 0.1 MHz and 20 MHz in increments of ≥10 kHz; UKAS accredited from 1 MHz to 20 MHz and compliant with ISO 17025
Directional response along two perpendicular directions in the range -70° to 70°
With the hydrophone calibration service established more than 30 years ago, NPL is in the best position to respond quickly to every enquiry regarding all commercial and prototype hydrophones, and to provide the best quality data with measurement uncertainty as low as 6%. The average turnaround time for calibrations is 2 weeks.
Our research and measurement solutions support innovation and product development. We work with companies to deliver business advantage and commercial success. Contact our Customer Services team on +44 20 8943 7070