PVDF Hydrophones
14/08/2003

Needle-type hydrophone probes
The miniature PVDF polymer hydrophone probes are designed for accurate ultrasonic exposimetry and associated field measurements. Their wide-band and flat frequency response properties make them uniquely suited for measurements of pressure-time wave forms in absolute terms or units. The small physical dimensions minimise acoustic disturbances and facilitate measurements where space is a limiting factor.

 

Features

The hydrophone probes show a number of excellent and unique features, such as:

  • Conformity with IEC 1102 and AIUM/NEMA standards
  • Enhanced bandwidth: <1 to >20 MHz
  • Excellent linearity and transient response
  • Small physical dimension for high geometrical resolution
  • Shielded element construction minimising EMI noise
     

Applications

High quality measuring devices for:

  • Testing and labelling of medical and industrial equipment
  • Transducer design - Imaging systems optimisation
  • Ultrasonic exposimetry
  • Calibration reference standard
     

Technical specifications

Type MH28-10 to MH28-4

  • Active element 28 µm PVDF foil, nickel electrodes
  • Diameter 0.4 to 1.0 mm
  • Typical sensitivity 45 nV/Pa (0.4 mm) or 200 nV/Pa (1.0 mm)
  • Frequency range 0.5 - >20 MHz
  • Calibrated (±1.5 dB) 1 - 20 MHz
  • Power supply not required Dynamic range 0 to >100 MPa, limited by amplifier noise
     

1 m low capacitance coaxial cable terminated with BNC connector.

All units are delivered in protective casing with individual calibration certificate.

 

Accessories

Buffer amplifier type BAS matches standard hydrophones type MH28-10 to MH28-4 with 1 m cable

and reduces ringing to a minimum. (Amplifier and hydrophone should be calibrated together to minimise calibration uncertainties.)

The amplier type PAN is intended for use where very low acoustic signals are measured with the standard hydrophones.

 

Calibration

Each hydrophone is supplied with a calibration certificate giving sensitivity as a continuous function of frequency from1 MHz to 20 MHz. (Enhanced bandwidth calibration available upon request.)

Calibration certificates are traceable to recognised national and international standards.

Calibration of hydrophones is performed under the National Danish Accreditation scheme DANAK which ensures:

  • Calibration in accordance with the quality assurance standard EN 45001
  • An assessment of the measuring capability of the testing laboratory by DANAK
     

Recalibration is recommended by the IEC standard 866 to be carried out at intervals no longer than one year. Recalibration service is offered as a continuous function of frequency up to 20 MHz for both FORCE and other type hydrophones. Enhanced bandwidth calibration is available upon request.

Discrete frequency directivity pattern measurements and effective hydrophone aperture are also available up to 20 MHz.

 

For more information, please contact:

Torben Sevel
Telephone (direct): +45 4326 7485
e-mail: ts@force.dk