Imaging Charged Particle Beams With Atomic Magnetometry

We present the results of 2-dimensional imaging of a charged particle beam using an atomic magnetometer. By propagating a beam of electrons through a low-pressure rubidium vapor, the alkali atoms experience a shift in their atomic states. A probe laser monitoring the $D_2$ transition of rubidium reacts with a rotation in its polarization angle directly proportional to the sensed magnetic field of the electron beam. The spatial dependence of the magnetic field can then be inferred using the CCD images of the probe laser polarization components. The obtained magnetic field distribution allows us to reconstruct the current density of the particle beam. As a proof of concept, we are able to image 1.5 mm diameter electron beams down to 20 $mu$A currents. These results are achieved through collaboration with Thomas Jefferson National Accelerator Facility to develop a non-invasive diagnostic tool for charged particle beams.