Verification of the results of the calibration of needle hydrophones on the measurement standard NDETU AUV-02-2018

The results of the verification of the calibration of needle hydrophones using the national primary measurement standard of the unit of ultrasonic pressure in the aquatic environment (NDETU AUV-02-2018) are presented. The main objective of the study was to confirm the accuracy of the calibration of needle hydrophones No. 2538 and No. 2515 by comparison with the calibration results obtained on the measurement standard at the Physikalisch-Technische Bundesanstalt (PTB), Germany. The paper describes the calibration methods used by laboratories to determine the sensitivity of hydrophones, including the two-transducer reciprocity method and the comparison method. The results of the calibration of needle hydrophones in the frequency range from 1 to 10 MHz obtained by the National Metrology Institute of Germany (PTB) and Ukraine (SE Research Institute “Systema”) were evaluated. Furthermore, the level of uncertainty of the calibration results was compared. The results of the study demonstrated a high degree of consistency in the measurement results. Added to this, the results confirmed the reliability of the results of the calibration of needle hydrophones using the NDETU AUV-02-2018 measurement standard by the calibration method selected and with the measurement equipment used. The conclusions confirmed the effectiveness of using the national measurement standard NDETU AUV-02-2018 and its conformity with international measurement standards, thus increasing the confidence in the results at the international level. Additionally, the study provides the ground for future international comparisons with measurement standards of other countries.