State-of-the-art Silicon Detectors for X-ray Spectroscopy

The semiconductor laboratory of the Max-Planck-Institutes for physics and for extraterrestrial physics develops and fabricates silicon sensors for scientific experiments in astronomy and highenergy physics, as well as for industrial applications. Among them are state-of-the-art detectors for X-ray imaging and spectroscopy. Their common features are the integration of the readout electronics on the detector chip and a fully depleted bulk with a non-structured thin entrance window, guaranteeing excellent energy resolution and high quantum efficiency over a wide energy range. Fully depleted and backside illuminated Charge Coupled Devices (pn-CCDs) have been developed and are operated successfully as focal plane detector of the XMM-Newton satellite. They have a sensitive area of 6 x 6 cm2 with a pixel size of 150 x 150 μm2, an equivalent noise charge of 4 el. rms. operating at 150 K, and an ultra-fast full frame readout time of 4.5 msec. The integrated detector-preamplifier structure DEPFET (DEpleted P-channel Field Effect Transistor) is the basic element of an Active Pixel Sensor (APS) with random accessible pixels, flexible readout modes, and the potential for repetitive non-destructive readout with subelectron resolution. Spectroscopy measurements of single DEPFET structures demonstrate an unequalled electronic noise of 2.2 el. rms at room temperature.