Characterizing current noise of commercial constant-current sources by using of an optically-pumped rubidium atomic magnetometer

TL;DR

This study presents a novel method using an optically-pumped rubidium atomic magnetometer to accurately measure and compare the current noise of commercial constant-current sources, highlighting the lowest noise model for high-precision applications.

Contribution

It introduces a calibration-based technique to characterize CCS noise using atomic magnetometry and compares six commercial sources, identifying the lowest noise model.

Findings

KeySight Model B2961A has the lowest current noise among tested CCSs.

The method effectively converts magnetometer sensitivity into current noise measurement.

Low-noise CCSs are crucial for high-sensitivity atomic magnetometry.

Abstract

This paper introduces a method for characterizing the current noise of commercial constant-current sources(CCSs) using a free-induction-decay(FID) type optically-pumped rubidium atomic magnetometer driven by a radio-frequency(RF) magnetic field. We convert the sensitivity of the atomic magnetometer into the current noise of CCS by calibrating the coil constant. At the same time, the current noise characteristics of six typical commercial low-noise CCSs are compared. The current noise level of the KeySight Model B2961A is the lowest among the six tested CCSs, which is 36.233 0.022 nA / Hz1/2 at 1-25 Hz and 133.905 0.080 nA / Hz1/2 at 1-100 Hz respectively. The sensitivity of atomic magnetometer is dependent on the current noise level of the CCS. The CCS with low noise is of great significance for high-sensitivity atomic magnetometer. The research provides an important reference for promoting the development of high precision CCS, metrology and basic physics research.