Fast X-ray chopper using hard disk drive's rotation

A very interesting idea that proposes the use of a motor in a hard disk drive as an X-ray chopper has been recently published. It can produce X-ray pulses of ms width and few μs rise time. In the research, the system was used to test the response of X-ray detectors such as ionization chambers and photo diodes. For more information, see the paper, "Hard disk drive based microsecond x-ray chopper for characterization of ionization chambers and photodiodes", O. Muller et al., Rev. Sci. Instrum. 86, 035105 (2015).