Ultrasonic Pulsed Doppler, a Novel Method for Nanoparticle Characterization

S. Africk
Prodyne Corp.,
United States

Keywords: nanoparticle, particle size distribution, ultrasonic backscatter


USPD is a unique ultrasonic backscatter technology for the characterization of nanoparticles in ongoing research and development. Particles are interrogated in motion and the backscattered energy is received at Doppler-shifted frequencies, allowing clutter-free detection of backscatter from particles in the sub-ten to 100 nm range. For sizing, particles are set into motion by high intensity interrogation ultrasound itself with velocities correlated with size and the backscatter power spectrum is converted to a Particle Size Distribution (PSD). This process is less labor intensive and expensive than TEM. Employing only a single small transducer, the USPD system can be incorporated into existing process equipment. Other advantages include measurement at high concentrations and with opaque solutions and better size resolution than with many conventional instruments. USPD can also measure concentration and flow fields with high spatial resolution and possibly mechanical properties of particles.