Meteorological radiosonde interface for atmospheric ion production rate measurements

A disposable balloon-carried instrument, interfaced to a commercial meteorological radiosonde for measuring the atmospheric ion production rate, is described. The sensor used is a gamma-sensitive Geiger tube, operated at 550 V bias, produced from a lightweight transformerless supply. The supply requires 15 V at 10 mA, and precision regulation is used to minimize the Geiger tube's response to bias voltage changes. The supply was stable to 0.1% for supply voltage variations between 15 and 25 V, and varied by less than 1% over temperatures from -53 to 25 degrees C during an atmospheric ascent. A digital counter incremented with each Geiger tube event, and the instantaneous count value was telemetered over a radiolink, time-stamped on reception to obtain the count rate. The derived ion production rate profile agrees with a standard parametrization to 5%. (c) 2005 American Institute of Physics.