STIX detection probability of an incoming photon flux as a function of energy. From top to bottom, we show the windows’ transmission, the grid transmission, the detector efficiency, and the STIX detection probability, which is the convolution of the different components. The solid (dashed) black line shows the STIX imaging (spectroscopy) probabilities. In gray, we highlight the effect of the attenuator insertion. The horizontal dotted line indicates the value of 1.