Assessment of non-X-ray background in the X-IFU

Abstract

No X-Ray mission has ever flown to L2, thus it is impossible to estimate the expected background level relying on existing data. The problem is also too complex to face using an analytical approach, and consequently the background estimates are performed using Monte Carlo simulations with the Geant4 software [RD1]. Geant4 is a toolkit that provides access to several different models to reproduce physical processes the user is interested in. Also, it is possible to set the simulation detail level to suit the user needs, balancing the accuracy of the results with the simulation speed. Thanks to this tool it is possible to recreate a virtual model of the instrument and its surroundings (the so-called Mass Model) and of the particle environment it will be placed into, and analyze how they interact with each other and ultimately, given the proper settings, to predict the expected instrument performances, among which the background level. Furthermore, it is possible to test the effect of changes to the instrument mass model (sensitivity analysis) and identify the configuration that optimizes the detector performances