PTB Successfully Tests Chip-Scale Atomic Magnetometer Sensor

Published on May 30, 2012 at 6:59 AM

By Kalwinder Kaur

Scientists from the Physikalisch-Technische Bundesanstalt (PTB) report successful testing of a new mini magnetic sensor for measuring brain activity. The sensor holds potential for medical applications including neurological diagnostics.

Magnetsensor Lineal

The Chip-scale Atomic Magnetometer (CSAM) sensor was developed by the National Institute of Standards and Technology (NIST) in the USA. PTB and NIST are collaborating in this study. PTB is contributing its experience in conducting biomagnetic measurements in magnetically shielded rooms.

The CSAM sensor was tested by PTB in its magnetically shielded room, where it passed tests for detecting stimulated and spontaneous magnetic fields of the brain. This sensor can operate at room temperature, which is a significant advantage over cryoelectronics that require complex cooling. Absorption changes that occur due to magnetic fields within a Rubidium gas cell are measured using miniaturized optics by the CSAM sensor. The study results were published in the Biomedical Optics Express journal.

As part of the study, the scientists placed the sensor at a distance of 4 mm from the head of a person. They detected magnetic fields of alpha waves behind the head. These alpha waves are a basic brain rhythm that occurs when a person relaxes. The scientists also identified brain fields that occur due to tactile stimuli processing. The study results were confirmed through a magnetoencephalography (MEG) measurement using superconducting quantum interference device (SQUID) technology. MEG measurements provide an indication of age dependent brain diseases and psychiatric disorders.

SQUIDs have been considered as the gold standard for measurement of very weak magnetic fields. These cryoelectronic sensors require very low operating temperatures that make them comparatively less versatile and more expensive than CSAMs. The present CSAMs are comparatively less sensitive, but they may be improved to provide better readings at lower costs.