Improving the LAD detector energy resolution with a novel sensor design

The Large Area Detector is built around an array of linear Silicon Drift Detectors read out by dedicated CMOS Application-Specific Integrated Circuits. Strict constraints on power consumption and energy resolution (200 eV FWHM at 6 keV for single-channel events, ≤ 240 eV FWHM overall), impose a tough trade-off. We developed a new sensor architecture to improve the performance following two strategies: firstly by confining the signal charge diffusion during drift to a single channel, and secondly by focusing this charge to a smaller anode reducing the preamplifier’s noise contribution. Preliminary results show single-anode events increasing from the original 40% to > 94%, with a significantly improved energy resolution.