What is recommended to verify measurements during calibration after establishing velocity and a DAC curve?

• A. Use an impedance meter for verification.
• B. Skip verification to save time.
• C. Calibrate using a cracked sample to see if you can detect it.
• D. Verify measurements against additional references to confirm accuracy and detect drift.

Answer: (D)

After you’ve determined the velocity and set up the DAC curve, verify measurements by checking them against additional reference standards. This step confirms that the entire measurement chain—transducer response, electronics, couplant, and path—still yields accurate readings and helps catch any drift over time. Using known reference blocks or artifacts with established reflectors gives you a direct comparison to what you should be seeing, so you can be confident in your calibration or know exactly when to adjust.

Impedance measurements don’t assess the acoustic pulse-echo response needed for UT calibration, skipping verification leaves you blind to drift, and calibrating with a cracked sample isn’t a reliable or safe way to verify measurement accuracy.