Operational amplifier parameters automated control in the enhanced low dose rate sensitivity effect investigation

During monitoring of the operational amplifiers (op amps) parameters exposed to ionizing radiation, it may be necessary to use several application circuits and register the criteria parameters for a sufficiently long time (up to tens of hours) that requires the whole process automation. Aims and objectives. The solution of the task of op-amp parameters automated control for a long time using the different op-amp application circuits Methods. The developed technique was used to control the most sensitive to the ionizing radiation exposure op-amp characteristics i.e. zero-offset voltage, input current and the performance during the exposure. The set of instruments controlled by PC was used to measuring schemes switching, power supply on-set and control, observed parameters registration. The interface software visua¬lized all controlled parameters results in real time with simultaneously logging was developed to control instruments and data registration. Results. The relations of the studied op-amp parameters on the accumulated dose for different exposure intensities have been obtained for op-amp exposed to 60Co gamma isotope source (total registration time was about 70 hours) It was shown that among investigating parameters only input current varies significantly in the considering exposure level interval. Experimental results are analyzed in the network of the today’ most popular conversion model of charge injection to surface states; coefficients of obtained results with model curves approximation were determined for the two different dose rates. Conclusion. A circuit for monitoring op-amp parameters during a radiation experiment is proposed, and software for controlling measuring equipment used for automated recording of op-amp response over a long period of time is developed. The methodology was tested in a real experiment with dose rate variation. It has been established that the low intensity effect is manifested in the op-amp, which cannot be described within the framework of the conversion model.