A high-sensitivity 16-channel magnetic sensor for magnetocardiographic experiments

Multichannel parallel magnetic measurements are required for various applications in many fields such as neuroscience and biomedical research. We recently constructed a portable, low-cost, high-sensitivity 16-channel magnetic sensor for magnetocardiography (MCG) applications. The sensor is based on a high-sensitivity atomic magnetometer (AM) with a novel configuration of nearly parallel pump and probe laser beams. The AM-based 16-channel magnetic sensing is realized in a single module by using a single large rubidium vapor cell, two broad laser beams, and a 16-channel photodiode matrix, leading projected 10-fold reduction of the cost of sensors. For MCG experiments with the sensor, its main components except lasers are located inside a magnetically shielded room. We describe the basic principle and the design of the 16-channel magnetic sensor. We also present human heart signals directly recorded by the sensor.