Response of silicon photomultipliers directly exposed to X-ray fluxes

Silicon photomultipliers are commonly used to detect the passage of radiation in matter via the collection of photons produced by the ionizing radiation in converting materials. We investigated the possibility of direct detection of high-intensity X-ray fluxes using the measurement of the current produced by silicon photomultipliers directly exposed to the X-ray beam, in absence of any converter material. We have analyzed the response of different devices directly exposed to the radiation produced by an X-ray tube. The signal-to-noise ratio of the response confirms that the current produced during the irradiation provides information on the X-ray flux intensity. We parametrize the current response of SiPM devices as function of the X-ray flux intensity. We verify that the parametrization is accurate down to the % level and we study the linearity of the response to investigate the prospects for possible applications in real-time X-ray beam monitoring and beam spatial profiling.