| 摘要 |
<p>An apparatus and method for measuring radiation field strength uses a pulse enabled G-M detector tube (13 or 14) and is based on the equation R=K/t, where r is the radiation field strength, t is the time till first strike, and K is a proportionality constant for the given apparatus. The G-M tube (13 or 14) is enabled by pulsing the bias voltage across the tube up into its active region and then measuring the elapsed time interval to the incident of first strike. Since the reciprocal of this time is proportional to the radiation field strength, all information necessary to determine the field strength has been obtained. A constant wait time is employed after each strike to ensure that the G-M tube full recovery time has expired, and the G-M tube is then enabled and the process repeated. Because of the random nature of radiation phenomena the confidence level that any given measurement is an accurate representation of the true average field strength is low. Many measurements are taken and averaged for high confidence factors. For low fields, the lost time due to the deliberate "wait after strike" is a small percentage of the total time, so is of little consequence. In high fields, the "time to strike" is short, so many measurements can be made, again rendering the lost time of little significance. </p> |
