Calibration of an alpha particle irradiator for in vitro cells irradiation

An alpha particle irradiator using Po radioactive sources was calibrated under specific conditions for cell irradiation. The energy spectrum of α-particles hitting the cell monolayer was measured by a surface barrier detector. The simulation of the results obtained with this detector was performed using the MCNPX Monte Carlo code with the same conditions used during the experimental measurements. Based on the experimental results the LET spectrum at the cell monolayer was extracted using the published Stopping Power and Range tables from the National Institute of Standards and Technology database. From this spectrum the average LET value was calculated to be (154 ± 9) keV/μm. In order to calculate the dose value at the cell monolayer, the alpha particle count rate hitting the cells was also estimated from the experimental measurements and compared with the activity of the source. Finally, the dose rate value at cell monolayer was calculated using the measured particle fluence.

Keywords: alpha radiation, cell irradiation, LET values, surface barrier detectors, Monte Carlo simulation, low radiation, alpha particle irradiators