Cucchetti, E.E.CucchettiPointecouteau, E.E.PointecouteauBarret, D.D.BarretLOTTI, SimoneSimoneLOTTIMACCULI, CLAUDIOCLAUDIOMACCULIMOLENDI, SILVANOSILVANOMOLENDIPajot, F.F.PajotPeille, P.P.PeillePIRO, LUIGILUIGIPIROPratt, G. W.G. W.Pratt2021-01-282021-01-282018978151061951797815106195240277-786Xhttp://hdl.handle.net/20.500.12386/30082The X-ray Integral Field Unit (X-IFU) is the cryogenic imaging spectrometer on board the future X-ray observatory Athena. With a hexagonal array of 3840 AC-biased Transition Edge Sensors (TES), it will provide narrow-field observations (5' equivalent diameter) with unprecedented high spectral resolution (2.5 eV up to 7 keV) over the 0.2 - 12 keV bandpass. Throughout its observations, the X-IFU will face various sources of X-ray background. Specifically, the so-called Non-X-ray Background (NXB) caused by the interaction of high-energy cosmic rays with the instrument, may lead to a degradation of its sensitivity in the observation of faint extended sources (e.g. galaxy clusters outskirts). To limit this effect, a cryogenic anti-coincidence detector (CryoAC) will be placed below the detector plane to lower the NXB level down to the required level of 5⊗10<SUP>-3</SUP> cts/s/cm<SUP>2</SUP>/keV over 2 - 10 keV. In this contribution, we investigate ways to accurately monitor the NXB and ensure the highest reproducibility in-flight. Using the limiting science case of the background-dominated observation of galaxy clusters outskirts, we demonstrate that a reproducibility of 2% on the absolute knowledge of the background is required to perform driving science objectives, such as measuring abundances and turbulence in the outskirts. Monitoring of the NXB in-flight through closed observations, the detector's CryoAC or the companion instrument (Wide Field Imager) will be used to meet this requirement.ELETTRONICOenConference paper10.1117/12.23121792-s2.0-85051840884000452819200110https://www.spiedigitallibrary.org/conference-proceedings-of-spie/10699/2312179/Reproducibility-and-monitoring-of-the-instrumental-particle-background-for-the/10.1117/12.2312179.full?SSO=12018SPIE10699E..4NCFIS/05 - ASTRONOMIA E ASTROFISICA