Weak current measuring device

Abstract

The invention relates to a weak current measuring device, which comprises a detection assembly, a conversion assembly, a power supply assembly and a calibration assembly, and is characterized in that the calibration assembly is used for correcting detection data of each assembly and is configured to select manual calibration or automatic calibration based on a current source condition of a current device to be detected. The automatic calibration comprises the following steps: adjusting to each detection gear, respectively carrying out detection for a plurality of times, and taking a detection mean value as a correction standard of detection data of each component. The weak current measuring device is designed based on the principle of a high-resistance method, the calibration assembly is designed to serve as a front assembly of the device, it is guaranteed that the device has the high speed when detecting weak current, meanwhile, the measuring range changing circuit is integrated between the calculation unit and the current signal conversion circuit, and the measuring precision is improved. A user can adjust the current to be measured to a proper measuring range according to the approximate range of the current to be measured, the measurement accuracy is ensured, the device has high performance and practicability at the same time, and a foundation is laid for practical application of radiopharmaceutical activity field measurement.

Description

technical field [0001] The invention relates to the technical field of extremely weak current detection, in particular to a weak current measuring device. Background technique [0002] Generally, currents below the nA level are defined as weak currents. In scientific research in many fields such as nuclear technology applications, ionizing radiation, electrochemistry, and materials science, it is often necessary to carry out detection of weak currents. Especially in nuclear medicine, as more and more short-lived or ultra-short-lived artificial nuclides are used in clinical diagnosis and treatment, these nuclides decay at a high speed over time. This characteristic is the absolute measurement of activity and needs to be carried out at any time. The results of the verification work caused great difficulties. [0003] At present, the China National Institute of Metrology (NIM) has developed a 4πγ high-voltage ionization chamber activity measurement system for rapid measurement...

AI Technical Summary

Problems solved by technology

The calibration component calibrates the data of the tiny current measuring device, which solves the problem that the calibration of an extremely weak current source is expensive, making it difficult to ensure that each current detection instrument is equipped with a current source that can provide it with a calibration signal, and in After providing fast and high-precision calibration, it also provides an implementation basis for the subsequent range accuracy design and noise reduction design of the tiny current measurement device, and solves the problems brought about by obtaining smaller volume, less noise and more accurate measurement range. Problems with increasing calibration difficulty

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