THE TETHERED FLOAT ULTRASONIC RADIOMETER

The exact equations for the behaviour of a tethered float radiation fo rce device are derived and shown to be analytically insoluble at the p resent time. In the limiting case of vertical supporting chains, the a nalysis becomes trivial and the device has a linear response. The cons truction and evaluation of such a device for assessing medical physiot herapy equipment is described and the results of a pilot study on ten clinical machines is presented. The poor relation between their actual and their nominal behaviour indicates the need for closer control of both manufacture and performance in the field.