Detection of low-magnetic fields by rubidium (87Rb) vapor cell

• Author(s): Maciel, Marino Jesus Correia ; Silva, M. F. ; Pimenta, Sara Filomena Ribeiro ; Correia, J. H.
• Date: 2021
• Persistent ID: https://hdl.handle.net/1822/89546
• Origin: RepositóriUM - Universidade do Minho
• Document Type: Conference paper
• Language: English
• Contributor(s): Universidade do Minho

Description

This paper describes the work carried out to assess the use of a quartz reference rubidium (87Rb) vapor cell for non-invasively magnetoencephalography, avoiding cryogenically cooled sensors as the Superconducting Quantum Interference Devices (SQUIDs). An experimental setup based on a cylindrical glass vapor cell of 87Rb (l = 75 mm, d =19 mm) was developed. The 87Rb cell was heated to around 75°C and it was optically pumped with polarized light (range 750-850 nm), tuned to the D1 transition of rubidium, for spin-polarization of the atoms, and the intensity of the light transmitted through the cell was detected using a photodiode. Without magnetic field, the photodiode current is maximized but when a small transverse magnetic field is present a measurable drop in light transmission occurs. A Magnetic Shielded Box (MSB) made by a nickel-iron ferromagnetic alloy, was used for nulling background magnetic fields and the transmittance light versus transverse magnetic field intensity (100-1000 nT) was measured.