Using a cylindrical piezoelectric transducer to focus ultrasound in superfluid helium Dillip Pradhan, Shriganesh Neeramoole, Neha Yadav and Ambarish Ghosh Eur. Phys. J. Spec. Top., 232 6 (2023) 949-955 Published online: 18 January 2023 DOI: 10.1140/epjs/s11734-023-00764-1