[An axicon lens for focussing ultrasound fields]

In this paper the properties of an ultrasonic axicon lens of 10 cm diameter are Investigated. This device generates a narrow ultrasonic beam in a range of 20 cm. The beam width varies from 1.7 to 0.5 mm in the frequency range from 1.7 to 5.5 megahertz. For practical applications a water path is necessary.