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The Mercury imaging X-ray spectrometer (MIXS) on board of ESA's fifth cornerstone mission BepiColombo will be the first space instrument using DEpleted P-channel FET (DEPFET) based detectors. The MIXS spectrometer comprises two channels with identical focal plane detectors and is dedicated to energy resolved imaging of X-ray fluorescence from the mercurial surface. [ABSTRACT FROM PUBLISHER]

The Mercury Imaging X-ray Spectrometer (MIXS) is one of the instruments on board the Mercury Planetary Orbiter of the fifth European Space Agency (ESA) cornerstone mission Bepi- Colombo. This spectrometer comprises two instruments and allows imaging X-ray spectroscopy of the Mercurian surface. The focal plane arrays for the energy and spatial resolved detection of X-rays are based on depleted P-channel FET (DEPFET) macropixel detectors. We report on the first electrical qualification measurements of DEPFET macropixel flight hardware, which are done at room temperature. The measurement of the transistor properties of all DEPFET pixels allows the selection of 100% electrically defect-free devices at an early stage directly after completion of the production process. Additionally, these measurements allow to investigate topics such as the homogeneity of transistor parameters across the detector matrix, to monitor die-to-die variations for matrices from the same wafer, and to investigate the differences between dies from different wafers in order to learn about the stability and reproducibility of the production process. The test results demonstrate good homogeneity and yield for the investigated detector matrices from the first production batch. [ABSTRACT FROM AUTHOR]

Energetic electrons of several hundred-kilo electron volts (keV) as used in transmission electron microscopy applications do not deposit their energy completely at their point of entry (PoE). Instead, in a detector with a thickness of 450 $\mu \text{m}$ , they produce randomly 3-D tracks often extending over many pixels. The length and the shape of these tracks strongly depend on the primary energy of the electrons. Statistically, an electron deposits most of its energy at the end of its track. The output of a tracking detector system is the pixelated 2-D projection of the energy deposition. The proposed convolutional neural network (CNN) is capable of performing a frame-based event analysis and PoE reconstruction. The resulting modulation transfer function (MTF) is 0.77 at a Nyquist frequency of 0.5 obtained from a slanted edge. It is based on a U-net with a specially designed loss function using the confusion matrix. The input data to the CNN only need to be offset corrected. The output of the CNN is a PoE map containing the probability of a PoE of an electron for each pixel and frame. The architecture of the designed CNN also allows reconstructing different frame sizes without retraining the network. [ABSTRACT FROM AUTHOR]

The Mercury Imaging X-ray Spectrometer is a highly novel instrument that is designed to map Mercury’s elemental composition from orbit at two angular resolutions. By observing the fluorescence X-rays generated when solar-coronal X-rays and charged particles interact with the surface regolith, MIXS will be able to measure the atomic composition of the upper ∼10-20 μm of Mercury’s surface on the day-side. Through precipitating particles on the night-side, MIXS will also determine the dynamic interaction of the planet’s surface with the surrounding space environment. MIXS is composed of two complementary elements: MIXS-C is a collimated instrument which will achieve global coverage at a similar spatial resolution to that achieved (in the northern hemisphere only – i.e. ∼ 50 – 100 km) by MESSENGER; MIXS-T is the first ever X-ray telescope to be sent to another planet and will, during periods of high solar activity (or intense precipitation of charged particles), reveal the X-ray flux from Mercury at better than 10 km resolution. The design, performance, scientific goals and operations plans of the instrument are discussed, including the initial results from commissioning in space. [ABSTRACT FROM AUTHOR]

DEPFET detectors are silicon (Si) active pixel sensors designed and manufactured in the Max-Planck-Institut semiconductor lab. Their high spatial resolution and high energy resolution in X-rays make them attractive for particle tracking in colliders and for X-ray astronomy. This technology is foreseen for the Wide Field Imager of the International X-ray Observatory currently in study with ESA, NASA, and JAXA. New DEPFET matrixes with 256\,\times\,256 pixels of 75-\mum pitch have been produced, mounted on ceramic boards with dedicated front-end electronics and integrated in a new setup able to acquire large-format images and spectra. Excellent homogeneity has been observed. Energy resolution as low as 127 eV FWHM at 5.9 keV has been obtained including all single events of the matrix back illuminated at -45\,^\circC and read out at a 300-frames/s rate. This paper presents experimental methods and results. [ABSTRACT FROM AUTHOR]