By Martino Marelli

We analyze the unconcentrated background of the EPIC/pn detector on board the X-ray satellite XMM-Newton. Our data set spans over a 12-years period and is the largest ever employed for this kind of study. Taking advantage of the tight relationship between EPIC/pn and EPIC/MOS2 measurements, we propose an improved technique to model the background of the pn camera.

We find a tight linear correlation between the pn unconcentrated background and the cosmic-ray protons flux as measured by SOHO/EPHIN. Through this, we quantify the contribution of cosmic-ray interaction to the pn unconcentrated background. We also reveal a second component which contributes (up to 70%) to the total pn unconcentrated background and is likely associated with the Cosmic X-ray Background.

Our findings provide an important observational confirmation of simulation results on Athena and suggest that a high energy particle monitor could contribute decisively to the reproducibility of the background for both experiments on Athena.

 Access to the manuscript in ADS.