Measuring magnetic field fluctuations for use in decreasing microbeam spot size

The microbeam system at the Radiological Research Accelerator Facility (RARAF) currently has a beam spot size of 0.8 microns in diameter. While this spot size is small enough to hit a targeted spot in the nucleus of a cell with a high degree of certainty, researchers at RARAF hope to accurately target even smaller components of cells in the future. This paper discusses a technique used to measure fluctuations in the magnetic field in the vicinity of the microbeam endstation, which cause the beam to be deflected. The deflection of the beam relates to an uncertainty in the beam spot, essentially increasing the size of the spot. Using the Honeywell HMC2003 3-axis Magnetic Sensor Hybrid integrated circuit, measurements were made to reach a better understanding of the magnetic field fluctuations and begin developments in counteracting these fluctuations to decrease the uncertainty in beam spot size. Fluctuations in the magnetic field were found on the submicron level that warrant further investigation into how these fluctuations may be counteracted.