A: DEPFET Active Pixel Sensors (APS) have been introduced as focal plane detectors for X-ray astronomy already in 1996. Fabricated on high resistivity, fully depleted silicon and back-illuminated they can provide high quantum efficiency and low noise operation even at very high read rates. In 2009 a new type of DEPFET APS, the DSSC (DEPFET Sensor with Signal Compression) was developed, which is dedicated to high-speed X-ray imaging at the European X-ray free electron laser facility (EuXFEL) in Hamburg. In order to resolve the enormous contrasts occurring in Free Electron Laser (FEL) experiments, this new DSSC-DEPFET sensor has the capability of nonlinear amplification, that is, high gain for low intensities in order to obtain singlephoton detection capability, and reduced gain for high intensities to achieve high dynamic range for several thousand photons per pixel and frame. We call this property "signal compression".Starting in 2015, we have been fabricating DEPFET sensors in an industrial scale CMOS foundry maintaining the outstanding proven DEPFET properties and adding new capabilities due to the industrial-scale CMOS process. We will highlight these additional features and describe the progress achieved so far. In a first attempt on double-sided polished 725 µm thick 200 mm high resistivity float zone silicon wafers all relevant device related properties have been measured, such as leakage current, depletion voltage, transistor characteristics, noise and energy resolution for X-rays and the nonlinear response. The smaller feature size provided by the new technology allows for an advanced design and significant improvements in device performance. A brief summary of the present status will be given as well as an outlook on next steps and future perspectives.

By combining a low noise fully depleted pnCCD detector with a columnar CsI(Tl) scintillator an energy dispersive spatial resolving detector can be realized with a high quantum efficiency in the range from below 0.5 keV to above 150 keV. The used scintillator system increases the pulse height of gamma-rays converted in the CsI(Tl), due to focusing properties of the columnar scintillator structure by reducing the event size in indirect detection mode (conversion in the scintillator). In case of direct detection (conversion in the silicon of the pnCCD) the relative energy resolution is 0.7% at 122 keV (FWHM = 850 eV) and the spatial resolution is less than 75 μm. In case of indirect detection the relative energy resolution, integrated over all event sizes is about 9% at 122 keV with an expected spatial precision of below 75 μm.

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Recent developments in the field of new materials and composites have been pushing for more powerful instrumentation in electron microscopy (EM). Besides the excellent spatial resolution needed to resolve nanoscale structures, the analytical capabilities of the instrument for revealing the composition are also very important.

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Initially developed as position-sensitive detectors for particle tracking [1], Silicon Drift Detectors (SDD) have become a standard tool in electron microscopy over the last two decades. The fact that these detectors are operated without liquid N 2 cooling as well as the continuously improving performance have made them fast and efficient devices for Energy-Dispersive X-Ray Spectroscopy (EDS).While the first employed SDD sensors had active areas of only 5 mm² or 10 mm², the detector size has been growing over the years, being driven by technological improvements and the market demand for increased signal intensity to achieve shorter measurement times. Nowadays, single channel SDDs with active areas up to 200 mm² are available [2]. The use of oval shaped detectors (Fig. 1a) in Transmission Electron Microscopes (TEM) enables close proximity to the sample and increases the collection solid angle for the x-rays up to 1 sr. Annular four-channel SDDs (Fig. 1b) can be placed between pole piece and sample and expand the solid angle up to 1.8 sr. This allows for much shorter measurement time even with challenging samples. System-integrated EDS detectors in TEM led to a massive increase in solid angle and for the first time enabled elemental mappings in a reasonable time [3,4].The detection of low energy x-rays has become a more and more important task, especially in the field of low-voltage electron microscopy, where low energetic L-and M-lines are used for the elemental analysis. Modern scientific fields, such as energy storage materials demand for the detection of elements below Carbon. Windowless detectors with improved energy resolution and optimized radiation entrance window nowadays enable light element detection down to Lithium at only 54 eV (Fig. 2b).The continuous improvement of Silicon Drift Detectors with internal JFET [5] as well as new preamplifier concepts for SDDs with external transistor [6] have led to detectors with better energy resolution and excellent high count rate performance. The energy resolution could meanwhile be enhanced down to very good values of 121 eV FWHM @ Mn-Kα (Fig. 2a). Newest detectors can achieve energy resolution values that are sufficiently good for many applications even at chip temperatures close to room temperature [5]. This opens the door to compact and innovative new detector designs where only a minimum cooling is required.This contribution will give a brief overview on the history and developments in the field of Silicon Drift Detectors in microanalysis over the past 20 years. Within this, we will concentrate on how applications in electron microscopy and consequently challenges for the detectors evolved over the years and how the devices had to be adapted to this. Developments, such as larger active areas, advanced chip geometries, new read-out concepts for improved high count rate performance as well as systemintegrated SDDs in Transmission Electron Microscopy will be considered.

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Introduced into the Energy Dispersive X-ray (EDX) Microanalysis applications more than 15 years ago, Silicon Drift Detectors (SDD) fabricated by PNDetector have established themselves as state-of-the-art detectors in many of the EDX systems used in SEMs and (S)TEMs. Over all these years we have been continuously working on improving the detector spectroscopic performance.