Coleman A J, Saunders J E, Preston R C, Bacon D R
Department of Medical Physics, St. Thomas' Hospital, London.
Ultrasound Med Biol. 1987 Oct;13(10):651-7. doi: 10.1016/0301-5629(87)90063-9.
Pressure waveforms in the acoustic field generated by a Dornier (HM3) shock-wave lithotripter have been measured using a bilaminar shielded PVDF membrane hydrophone in water. Using these waveforms, values of the peak-positive (p+) and peak-negative pressure (p-) at various positions in the field have been estimated. At the focus, p+ is 38.6 MPa (standard deviation = 9.0 MPa) and p- is 10.1 MPa (standard deviation = 1.0 MPa) at 20 kV discharge potential and an electrode separation in the range 1.3 to 2.4 mm. The peak-positive pressure is found to fall to 50% (-6 dB level) at about 60 mm either side of the focus on the major axis of the reflector and on a 10 mm radius circle around the focus in the focal plane. A shot-to-shot variation of +/- 25% in p+ is attributed to the inherent variability of the electrical discharge which may result in changes in the exact position and strength of the acoustic field. The results reported are considered to be more accurate than those of previous measurements due to the relatively flat frequency response of this type of hydrophone.
使用双层屏蔽聚偏二氟乙烯（PVDF）薄膜水听器在水中测量了多尼尔（HM3）冲击波碎石机产生的声场中的压力波形。利用这些波形，估算了声场中不同位置的峰值正压（p+）和峰值负压（p-）。在焦点处，在20 kV放电电位且电极间距在1.3至2.4 mm范围内时，p+为38.6 MPa（标准差 = 9.0 MPa），p-为10.1 MPa（标准差 = 1.0 MPa）。发现在反射器主轴上焦点两侧约60 mm处以及焦平面上围绕焦点的半径为10 mm的圆上，峰值正压降至50%（-6 dB水平）。p+中±25%的逐次变化归因于放电的固有变异性，这可能导致声场的精确位置和强度发生变化。由于这种类型的水听器具有相对平坦的频率响应，所报告的结果被认为比以前的测量结果更准确。
