A simple test device for electrometers

Electrometers used in dosimetric instruments need to be checked regularly in order to measure and maintain the prescribed dose to the patient. This paper describes the function of a simple but accurate test device for electrometers. A number of electrometers have been tested and compared with calibrations performed by the Swedish Standard Dosimetry Laboratory (SSDL). The device can be used to test current, resistance, voltage and charge measurements. The charge can be conducted to the electrometer in different ways, and the input resistance of the electrometer can also be determined. The calibration factors obtained by the device are in good agreement with results obtained from calibrations at the SSDL.