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The Digital Pixel Test Structure (DPTS) is a monolithic active pixel sensor prototype chip designed to explore the TPSCo 65 nm ISC process in the framework of the CERN-EP R&D on monolithic sensors and the ALICE ITS3 upgrade. It features a 32 × 32 binary pixel matrix at 15 μm pitch with event-driven readout, with GHz range time-encoded digital signals including Time-Over-Threshold. The chip proved fully functional and efficient in testbeam allowing early verification of the complete sensor to readout chain. This paper focuses on the design, in particular the digital readout and its perspectives with some supporting results.

Ochratoxin A (OTA) is a mycotoxin produced by species of Penicillium and Aspergillus, and is found in many commodities including cereal grains, nuts, and coffee. OTA is a renal carcinogen and nephrotoxin at high concentrations, targeting the proximal tubules. This study uses transcriptomics and the previously reported apical data (Bondy et al., 2021) to infer mode-of-action of OTA toxicity in male and female rats exposed to low doses of OTA in utero and throughout development. Our findings support a male-specific activation of the innate and adaptive immune responses in F1 pups to OTA exposure. This was not found in the female F1 pups, and may be due to female-specific increased p38 activity and VDR signaling. Differentially expressed genes related to karyomegaly, MAPK activity, and immune activation appears to develop from in utero exposure to OTA whereas those related to decreased kidney and liver function, and changes to reproductive pathways occur in both rat generations. Together, these transcriptional results confirm that dietary exposure to OTA causes renal toxicity as well as alterations to hepatic and reproductive pathways in rats. In utero exposure of rats to OTA results in sex-specific alterations in immune response pathways, VDR signaling, and p38 activity.

The application of impact ionization for the measurement of micrometeoroids in space is a sensitive and established method for particles in the size range between a few nanometers and a few micrometers. For the measurement of micrometeoroid trajectories, the knowledge of the velocity vector and the related impact position is required. A typical impact ionization detector employs a hemispherically shaped conductive metal target, and a hemispherical grid electrode. The impact charge is dependent on the particle mass, particle speed and incident angle. For a collimated particle flux which is parallel to the symmetry axis, the impact direction and its related impact angle relative to the target normal varies with the radial distance from the symmetry axis. It is therefore essential to consider the impact position during calibration of impact ionization detectors. Furthermore, the induced charge signal shape varies with impact position. We perform simulations with the Coulomb software package and we do compare the results with experimental data. An empirical formula is derived to determine the impact location of the particle from the target and grid induction signals.

Ochratoxin A (OTA) is a mycotoxin produced by Aspergillus and Penicillium molds. Grain-based foods account for most human dietary exposures to OTA. OTA is a teratogen, but its reproductive and developmental effects are poorly understood. A one-generation reproductive toxicity study was conducted with groups of 16 male and 16 female Fischer rats exposed to 0, 0.026, 0.064, 0.16, 0.4 or 1.0 mg OTA/kg in diet. Dams exposed to 1.0 mg OTA/kg diet had statistically significant F1 pup losses between implantation and postnatal day (PND 4). Delays in preputial separation (PPS) and vaginal opening (VO) were indicative of delayed puberty in F1 rats. Mild renal lesions in nursing pups indicated that exposure prior to weaning impacted the kidneys. The developing kidney was more susceptible to OTA than the adult kidney. Significant increases in multi-oocyte follicles (MOFs) and proportional changes in resting and growing follicles were observed in F1 female ovaries. Plasma testosterone was reduced in F0 males, and there were negative effects on sperm quality in F0 and F1 male rats. The results confirm that continuous dietary exposure to OTA causes post-implantation fetotoxicity in dams, and renal and reproductive toxicity in their male and female offspring.

A dust trajectory detector placed on the lunar surface is exposed to extend people’s knowledge on the dust environment above the lunar surface. The new design of Lunar Dust eXplorer (LDX) is well suited for lunar or asteroid landers with a broad range of particle charges (0.1–10 fC), speeds (few m s−1 to few km s−1) and sizes (0.1–10 μ m). The calibration of dust trajectory detector is important for the detector development. We do present experimental results to characterize the accuracy of the newly developed LDX laboratory model. Micron sized iron particles were accelerated to speed between 0.5 and 20 km s−1 with primary charges larger than 1 fC. The achieved accuracies of the detector are ± 5 % and ± 7 % for particle charge and speed, respectively. Dust trajectories can be determined with measurement accuracy better than ± 2°. A dust sensor of this type is suited for the exploration of the surface of small bodies without an atmosphere like the Earth’s moon or asteroids in future, and the minisatellites are also suitable carriers for the study of interplanetary dust and manned debris on low Earth orbits.

–To understand the process of cosmic dust particle impacts and translate cratermorphology on smoothed metallic surfaces to dust properties, correct calibration of theexperimental impact data is needed. This article presents the results of studies of cratermorphology generated by impacts using micron-sized polypyrrole (PPy)-coated olivineparticles. The particles were accelerated by an electrostatic dust accelerator to high speedsbefore they impacted onto polished aluminum targets. The projectile diameter and velocityranges were 0.3–1.2 lm and 3–7kms 1 . After impact, stereopair images of the craters weretaken using scanning electron microscope and 3-D reconstructions made to providediameter and depth measurements. In this study, not just the dimensions of crater diametersand depths, but also the shape and dimensions of crater lips were analyzed. The craterscreated by the coated olivine projectiles are shown to have complicated shapes believed tobe due to the nonspherical shape of the projectiles.INTRODUCTIONMicron-sized cosmic dust particles have attractedmuch attention as they are a valuable source of data onsmall bodies in the solar system. The properties ofcosmic dust play an important role in the understandingof some astronomical observations. The simplestexperiment for studying the cosmic dust is the exposureof a smooth and ductile metal to space for retrieval at alater date. A dust grain impacting onto the exposedmetal surface at more than 1 km s

Cation and anion impact ionization mass spectra of polypyrrole-coated pyrrhotite cosmic dust analogue particles are analysed over a range of cosmically relevant impact speeds. Spectra with mass resolutions of 150–300 were generated by hypervelocity impacts of charged particles, accelerated to up to 37 km s −1 in a Van de Graaff electrostatic accelerator, onto a silver target plate in the Large Area Mass Analyzer (LAMA) spectrometer. Ions clearly indicative of the polypyrrole overlayer are identified at masses of 93, 105, 117, 128 and 141 u. Organic species, predominantly derived from the thin (20 nm) polypyrrole layer on the surface of the particles, dominate the anion spectra even at high ( > 20 km s − 1 ) impact velocities and contribute significantly to the cation spectra at velocities lower than this. Atomic species from the pyrrhotite core (Fe and S) are visible in all spectra at impact velocities above 6 km s −1 for 56 Fe + , 9 km s −1 for 32 S + and 16 km s −1 for 32 S − ions. Species from the pyrrhotite core are also frequently visible in cation spectra at impact speeds at which surface ionisation is believed to dominate ( 10 km s − 1 ) , although the large number of organic peaks complicates the identification of characteristic molecular species. A thin oxidised surface layer on the pyrrhotite particles is indicated by weak spectral features assigned to iron oxides and iron oxy-hydroxides, although the definitive identification of sulfates and hydrated sulfates from the oxidation process was not possible. Silver was confirmed as an excellent choice for the target plate of an impact ionization mass spectrometer, as it provided a unique isotope signature for many target-projectile cluster peaks at masses above 107–109 u. The affinity of Ag towards a dominant organic fragment ion (CN − ) derived from fragmentation of the polypyrrole component led to molecular cluster formation. This resulted in an enhanced sensitivity to a particular particle component, which may be of great use when investigating astrobiologically relevant chemicals, such as amino acids.

This paper details initial results from a study of electrical effects resulting from hypervelocity impacts at a Van de Graaff dust accelerator. Iron particles between 10 −15 g and 10 −10 g in mass were impacted on several different metallic targets at speeds of 1 km/s to 50 km/s. The goal of this study is to characterize the impact-generated plasma and associated RF emission. Results are presented from data collected using retarding potential analyzers. The rate of signal detection was found to have a dependence both on material and on target bias. From a single analyzer, some signal waveforms exhibited oscillatory behavior which is significant in determining the effect of impacts on spacecraft. Using two analyzers at different distances from the target, the expansion speed of the impact plasma was measured to be between 10 km/s and 30 km/s.

A newly developed position sensitive detector was implemented in the beam line of the Heidelberg dust accelerator. By charge induction, the detector enables the position of a dust particle to be determined without affecting its motion. The detector consists of four pairs of parallel plates, connected to a single common charge amplifier. The charge induced on the plates varies as a function of the dust particle trajectory, producing simple, easily interpreted signals. Using a segmented target installed in the beam line for a second independent measure of the trajectory, the position detector has been calibrated, allowing the detector signal to be mapped to a dust particle position. The resulting calibration curve indicates that the detector's position accuracy is approximately 0.14 mm, based on an average SNR of 700 for dust particles passing through the centre of the detector. The minimum dust charge for reliable detection was found to be about 1.1 fC. A detector simulation was used to produce a calibration curve that confirms the experimental results.

Investigating the dynamical and physical properties of cosmic dust can reveal a great deal of information about both the dust and its many sources. Over recent years, several spacecraft (e.g., Cassini, Stardust, Galileo, and Ulysses) have successfully characterised interstellar, interplanetary, and circumplanetary dust using a variety of techniques, including in situ analyses and sample return. Charge, mass, and velocity measurements of the dust are performed either directly (induced charge signals) or indirectly (mass and velocity from impact ionisation signals or crater morphology) and constrain the dynamical parameters of the dust grains. Dust compositional information may be obtained via either time-of-flight mass spectrometry of the impact plasma or direct sample return. The accurate and reliable interpretation of collected spacecraft data requires a comprehensive programme of terrestrial instrument calibration. This process involves accelerating suitable solar system analogue dust particles to hypervelocity speeds in the laboratory, an activity performed at the Max Planck Institut fur Kernphysik in Heidelberg, Germany. Here, a 2 MV Van de Graaff accelerator electrostatically accelerates charged micron and submicron-sized dust particles to speeds up to 80 km s−1. Recent advances in dust production and processing have allowed solar system analogue dust particles (silicates and other minerals) to be coated with a thin conductive shell, enabling them to be charged and accelerated. Refinements and upgrades to the beam line instrumentation and electronics now allow for the reliable selection of particles at velocities of 1–80 km s−1 and with diameters of between 0.05 μm and 5 μm. This ability to select particles for subsequent impact studies based on their charges, masses, or velocities is provided by a particle selection unit (PSU). The PSU contains a field programmable gate array, capable of monitoring in real time the particles’ speeds and charges, and is controlled remotely by a custom, platform independent, software package. The new control instrumentation and electronics, together with the wide range of accelerable particle types, allow the controlled investigation of hypervelocity impact phenomena across a hitherto unobtainable range of impact parameters.

Hypervelocity impact testing at the Max Planck Institute for Nuclear Physics was undertaken with a suite of RF, optical, and plasma sensors. Iron particles between 10 10 g and 10 15 g were accelerated to speeds of 1 km/s to 50 km/s using a Van de Graa dust accelerator and were impacted on metallic targets. The retarding potential analyzers (RPAs) designed and constructed to measure impact-generated plasma are described in detail. Several optical signals from a photomultiplier tube were detected and found to be temporally coincident with impact events that also generated measurable plasma. The plasma measurements from the RPAs indicate a dependence on target electrical bias and material. The expansion speed of plasma generated from impacts on unbiased tungsten was found to be approximately 20 km/s.

Solid-state detectors that operate in orbit are required to withstand harsh space environment conditions. Among the various phenomena able to damage the sensors, X-ray detectors are subjected to impacts of orbital debris and micrometeoroids whenever, to be sensitive to low energy photons, they need to be ``directly'' exposed to the sky. The LOFT mission, proposed for the M3 class opportunity of the ESA Cosmic Vision, has a very-large sensitive area (greater than 10 m2) made of Silicon Drift Detectors (SDD). Moreover, the satellite includes an X-ray Wide-Field Monitor based on the same SDD detectors. Here we present the results of a test campaign at the Cosmic Dust Accelerator Facility at MPIK in Heidelberg aimed at the space qualification of the detectors with respect to this phenomenon.

Hypervelocity micro particles (mass

Space weather including solar activity and background plasma sets up spacecraft conditions that can magnify the threat from hypervelocity impacts. Hypervelocity impactors include both meteoroids, traveling between 11 and 72 km/s, and orbital debris, with typical impact speeds of 10 km/s. When an impactor encounters a spacecraft, its kinetic energy is converted over a very short timescale into energy of vaporization and ionization, resulting in a small, dense plasma. This plasma can produce radio frequency (RF) emission, causing electrical anomalies within the spacecraft. In order to study this phenomenon, we conducted ground-based experiments to study hypervelocity impact plasmas using a Van de Graaff dust accelerator. Iron projectiles ranging from 10−16 g to 10−11 g were fired at speeds of up to 70 km/s into a variety of target materials under a range of surface charging conditions representative of space weather effects. Impact plasmas associated with bare metal targets as well as spacecraft materials were studied. Plasma expansion models were developed to determine the composition and temperature of the impact plasma, shedding light on the plasma dynamics that can lead to spacecraft electrical anomalies. The dependence of these plasma properties on target material, impact speed, and surface charge was analyzed. Our work includes three major results. First, the initial temperature of the impact plasma is at least an order of magnitude lower than previously reported, providing conditions more favorable for sustained RF emission. Second, the composition of impact plasmas from glass targets, unlike that of impact plasmas from tungsten, has low dependence on impact speed, indicating a charge production mechanism that is significant down to orbital debris speeds. Finally, negative ion formation has a strong dependence on target material. These new results can inform the design and operation of spacecraft in order to mitigate future impact-related space weather anomalies and failures.

A novel, non-invasive technique for accurate measurements in animals (Kyniklometry) is presented. Kyniklometry (derived from greek ŏ kúvikloz the rabbit) determines the distance between soft tissue landmarks in conscious rabbits, in particular the rear lower leg. Each measurement consists of six subsequent and independent estimations of this distance, with a technical error of 79 microns (study I), respectively 83 microns (study II). The angle of the relaxed sitting animal's knee is approximately 45 infinity, and remains individually almost constant during subsequent measurements. The precision of the device was compared with X-ray stereophotogrammetry (technical error 30 microns). Five female New Zealand White rabbits were measured for 13 consecutive days at 24-hour-intervals both by kyniklometry and X-ray stereophotogrammetry (study I). The mean increment of 5 kyniklometric series of ten (3rd to 13th day) 24-hour-increments was 0.988 mm, the mean 24-hour-variance was 0.244 mm2. Sixty point five percent of this variance could be explained by parallel right/left leg soft tissue variation. Only 5% of the variance was explicable by the technical error. The 24-hour-correlation between kyniklometry and X-ray stereophotogrammetry was significant with r = 0.889 and p less than 0.001. Kyniklometric measurements were also performed in 5 female rabbits for 56 days at 24-hour-intervals (study II). We found spontaneous periodicity once every 8 to 14 days. There was a diurnal variation of rear lower leg increment with maxima in the early morning hours.