Fig. 3

Representative examples of 2D positive pressure maps across the focus in XY plane, measured a inside the magnet bore and b outside the magnet room at a nominal acoustic power of 100 W. c The absolute pressure difference map between inside and outside measurements. d The peak positive pressures (p⁺, top two curves) and peak negative pressures (p⁻, bottom two curves) obtained inside the magnet bore and outside the magnet room at nominal acoustic powers of 50–500 W. Triangles and circles represent pressures acquired outside the magnet room and inside the magnet bore, respectively