GB/T 7966-2022 in English

Analysis of the core content of the standard

GB/T7966-2022 is equivalent to IEC61161:2013, which specifies the method of measuring the total radiated power of an ultrasonic transducer in a liquid using a radiation force balance.

• Frequency range: 0.5MHz-25MHz (≤1W) and 0.75MHz-5MHz (≤20W)
• Sound field type: Parallel, divergent and focused ultrasonic field
• Balance type: Gravity or force feedback radiation force balance

Key technical requirements

1. Target design specifications

Note: Special target design is required in the focused sound field, see Appendix E of the standard for details.

2. Measurement system requirements

• Balance accuracy: The resolution needs to match the measurement level (e.g. 10mW corresponds to 0.68mg equivalent mass)
• Water quality requirements: When the power is greater than 1W, degassed water with an oxygen content of <4mg/L must be used
• Environmental control: Vibration and air flow must be isolated, and the influence of temperature fluctuations must be ≤1%

Measurement uncertainty analysis

Chapter 7 of the standard lists 21 sources of uncertainty in detail, mainly including:

Implementation Recommendations

1. Calibration process

1. Use standard weights to calibrate the balance system (including target in water)
2. Use a reference ultrasonic source for system-level calibration (traceable to the national standard)
3. Calibration cycle: every 2 years or when the system sensitivity changes

2. Special treatment of focused acoustic field

For focused transducers (γ≥25°), the correction formula must be used:

P = 2cF/(1+cosγ) (circular transducer)

This correction can compensate for the radiation force measurement deviation caused by the convergence of the sound field.

3. Notes on Industrial Applications

• The target temperature rise needs to be monitored during high-power measurements (may reach over 50°C)
• Scanning mode measurements require increasing the target size and evaluating the angle sensitivity
• High-frequency (＞10MHz) measurements require special control of the acoustic flow effect