Characterisation and testing of CHEC-M—A camera prototype for the small-sized telescopes of the Cherenkov telescope array

The Compact High Energy Camera (CHEC) is a camera design for the Small-Sized Telescopes (SSTs; 4 m diameter mirror) of the Cherenkov Telescope Array (CTA). The SSTs are focused on very-high-energy -ray detection via atmospheric Cherenkov light detection over a very large area. This implies many individual units and hence cost-effective implementation, as well as shower detection at large impact distance, and hence large field of view (FoV), and efficient image capture in the presence of large time gradients in the shower image detected by the camera. CHEC relies on dual-mirror optics to reduce the plate-scale and make use of 6 6 mm pixels, leading to a low-cost (150 k€), compact (0.5 m 0.5 m), and light (45 kg) camera with 2048 pixels providing a camera FoV of 9 degrees. The CHEC electronics are based on custom TARGET (TeV array readout with GSa/s sampling and event trigger) application-specific integrated circuits (ASICs) and field programmable gate arrays (FPGAs) sampling incoming signals at a gigasample per second, with flexible camera-level triggering within a single backplane FPGA. CHEC is designed to observe in the -ray energy range of 1–300 TeV, and at impact distances up to 500 m. To accommodate this and provide full flexibility for later data analysis, full waveforms with 96 samples for all 2048 pixels can be read out at rates up to 900 Hz. The first prototype, CHEC-M, based on multi-anode photomultipliers (MAPMs) as photosensors, was commissioned and characterised in the laboratory and during two measurement campaigns on a telescope structure at the Paris Observatory in Meudon. In this paper, the results and conclusions from the laboratory and on-site testing of CHEC-M are presented. They have provided essential input on the system design and on operational and data analysis procedures for a camera of this type. A second full-camera prototype based on Silicon photomultipliers (SiPMs), addressing the drawbacks of CHEC-M identified during the first prototype phase, has already been built and is currently being commissioned and tested in the laboratory.J. Zorn ... A. Malouf ... G. Rowell ... et al

SPECTROModule: A modular in-situ spectroscopy platform for exobiology and space sciences

The evolution of the solar system and the origin of life remain some of the most intriguing questions for humankind. Addressing these questions experimentally is challenging due to the difficulty of mimicking environmental conditions representative for Early Earth and/or space conditions in general in ground-based laboratories. Performing experiments directly in space offers the great chance to overcome some of these obstacles and to possibly find answers to these questions. Exposure platforms in Low Earth Orbit (LEO) with the possibility for long-duration solar exposure are ideal for investigating the effects of solar and cosmic radiation on various biological and non-biological samples. Up to now, the Exobiology and space science research community has successfully made use of the International Space Station (ISS) via the EXPOSE facility to expose samples to the space environment with subsequent analyses after return to Earth. The emerging small and nanosatellite market represents another opportunity for astrobiology research as proven by the robotic O/OREOS mission, where samples were monitored in-situ, i.e. in Earth orbit. In this framework, the European Space Agency is developing a novel Exobiology facility outside the ISS. The new platform, which can host up to four different experiments, will combine the advantages of the ISS (long-term exposure, sample return capability) with near-real-time in-situ monitoring of the chemical/biological evolution in space. In particular, ultraviolet–visible (UV–Vis) and infrared (IR) spectroscopy were considered as key non-invasive methods to analyse the samples in situ. Changes in the absorption spectra of the samples developing over time will reveal the chemical consequences of exposure to solar radiation. Simultaneously, spectroscopy provides information on the growth rate or metabolic activities of biological cultures. The first quartet of experiments to be performed on-board consists of IceCold, OREOcube and Exocube (dual payload consisting of ExocubeChem and ExocubeBio). To prepare for the development of the Exobiology facility, ground units of the UV–Vis and IR spectrometers were studied, manufactured and tested as precursors of the flight units. The activity led to a modular in-situ spectroscopy platform able to perform different measurements (e.g. absorbance, optical density, fluorescence measurements) at the same time on different samples. We describe here the main features of the ground model platform, the verification steps, results and approach followed in the customization of commercial–off-the-shelf (COTS) modules to make them suitable for the space environment. The environmental tests included random and shock vibration, thermal vacuum cycles in the range −20 °C to +40 °C and irradiation of the components with a total dose of 1800 rad (18 Gy). The results of the test campaign consolidated the selection of the optical devices for the Exobiology Facility. The spectroscopic performance of the optical layout was tested and benchmarked in comparison with state-of-the-art laboratory equipment and calibration standards showing good correlation. This includes spectra of samples sets relevant for the flight experiments and a performance comparison between the SPECTROModule ground model and state-of-the-art laboratory spectrometers. Considering the large number of samples and different types of optical measurements planned on-board the ISS, the main outcome was the implementation of an LED-photodiode layout for the optical density and fluorescence measurements of IceCold (42 samples) and ExocubeBio (111 samples); while the UV–Vis spectrometer will be mainly focused on the change of the absorption spectra of the 48 samples of OREOcube.The ExocubeChem samples (in total 48) will be analysed by infrared spectroscopy. The ground platform supports the establishment of analogue research capabilities able to address the long-term objectives beyond the current application

SPECTROModule: A modular in-situ spectroscopy platform for Exobiology and Space Sciences

The evolution of the solar system and the origin of life remain some of the most intriguing questions for humankind. Addressing these questions experimentally is challenging due to the difficulty to mimic environmental conditions representative for Early Earth and/or space conditions in general in ground based laboratories. Performing experiments directly in space offers the great chance to overcome some of these obstacles and to possibly find answers to these questions. Exposure platforms in Low Earth Orbit (LEO) with the possibility for long-duration solar exposure are ideal for investigating the effects of solar and cosmic radiation on various biological and non-biological samples. Up to now, the exobiology and space science research community has successfully made use of the International Space Station (ISS) via the EXPOSE facility to expose samples to the space environment with subsequent analyses after return to earth. The emerging small and nanosatellite market represents another opportunity for astrobiology research as proven by the O/OREOS mission, where samples were analyzed in-situ. In this framework, the European Space Agency is planning the development of a novel Exobiology facility outside the ISS. The new platform, which can host up to seven different experiments, will combine the advantages of the ISS (long-term exposure, sample return capability) with near-real time in-situ monitoring of the chemical/biological evolution in space. In particular, ultraviolet-visible (UV-VIS) and infrared (IR) spectroscopy have been considered as key non-invasive methods to analyze the samples in-situ. Changes in the absorption spectra of the samples developing over time will reveal the chemical consequences of exposure to solar radiation. Simultaneously, spectroscopy provides information on the growth rate or metabolic activities of biological cultures. The first four selected experiments to be performed on-board are IceCold and OREOcube, Exocube-bio and -chem. To prepare for the development of the Exobiology facility, ground units of the UV-VIS and IR spectrometers have been studied, manufactured and tested as precursors of the flight units. The activity led to a modular in–situ spectroscopy platform able to perform different measurements (e.g. absorbance, optical density, fluorescence measurements) at the same time on different samples. The paper will describe the main features of the platform installed under a solar simulator, the verification steps and approach followed in the customization of components –off-the shelf (COTS) to make them suitable for the space environment. The ground platform supports the establishment of analogue research capabilities able to address the long term objectives beyond the current application

SPECTROModule: A modular in-situ spectroscopy platform for Exobiology and Space Sciences

The evolution of the solar system and the origin of life remain some of the most intriguing questions for humankind. Addressing these questions experimentally is challenging due to the difficulty to mimic environmental conditions representative for Early Earth and/or space conditions in general in ground based laboratories. Performing experiments directly in space offers the great chance to overcome some of these obstacles and to possibly find answers to these questions. Exposure platforms in Low Earth Orbit (LEO) with the possibility for long-duration solar exposure are ideal for investigating the effects of solar and cosmic radiation on various biological and non-biological samples. Up to now, the exobiology and space science research community has successfully made use of the International Space Station (ISS) via the EXPOSE facility to expose samples to the space environment with subsequent analyses after return to earth. The emerging small and nanosatellite market represents another opportunity for astrobiology research as proven by the O/OREOS mission, where samples were analyzed in-situ. In this framework, the European Space Agency is planning the development of a novel Exobiology facility outside the ISS. The new platform, which can host up to seven different experiments, will combine the advantages of the ISS (long-term exposure, sample return capability) with near-real time in-situ monitoring of the chemical/biological evolution in space. In particular, ultraviolet-visible (UV-VIS) and infrared (IR) spectroscopy have been considered as key non-invasive methods to analyze the samples in-situ. Changes in the absorption spectra of the samples developing over time will reveal the chemical consequences of exposure to solar radiation. Simultaneously, spectroscopy provides information on the growth rate or metabolic activities of biological cultures. The first four selected experiments to be performed on-board are IceCold and OREOcube, Exocube-bio and -chem. To prepare for the development of the Exobiology facility, ground units of the UV-VIS and IR spectrometers have been studied, manufactured and tested as precursors of the flight units. The activity led to a modular in–situ spectroscopy platform able to perform different measurements (e.g. absorbance, optical density, fluorescence measurements) at the same time on different samples. The paper will describe the main features of the platform installed under a solar simulator, the verification steps and approach followed in the customization of components –off-the shelf (COTS) to make them suitable for the space environment. The ground platform supports the establishment of analogue research capabilities able to address the long term objectives beyond the current application

Polymorphisms in the angiotensin-converting enzyme gene are associated wit unipolar depression, ACE activity and hypercortisolism.

Angiotensin-converting enzyme (ACE) is assumed to influence the activity of the hypothalamic-pituitary-adrenocortical (HPA) system, which shows hyperactivity in the majority of patients with major depression. The ACE gene, known to be associated with cardiovascular disorders, which in turn are accompanied with an increased susceptibility for depression, is therefore a promising candidate gene for affective disorders. We investigated the genetic association between 35 single-nucleotide polymorphisms (SNPs) and an insertion/deletion (I/D)-polymorphism in the ACE gene and the susceptibility for unipolar major depression together with the genetic association with ACE serum activity and functional parameters of the HPA system. Two independent case/control samples with a total of 843 unrelated unipolar depressed patients and 1479 healthy controls were investigated. A case/control sample was screened to detect genetic associations with unipolar major depression. In addition, a replication sample was used to confirm the detected associations and to further investigate functional consequences of the genetic variants associated with depression. In the screening sample, two SNPs within the ACE gene were significantly associated with unipolar major depression. The association with unipolar major depression of one SNP (rs4291) located in the promoter region of the ACE gene was confirmed in our replication sample. The T-allele of this SNP was associated with depression and depressed T-allele carriers showed higher ACE serum activity and HPA-axis hyperactivity. Variants of the ACE gene such as SNP rs4291 are suggested susceptibility factors for unipolar major depression. We could show that SNP rs4291 influences ACE activity and HPA-axis hyperactivity and might therefore represent a common pathophysiologic link for unipolar depression and cardiovascular disease

A highly miniaturized satellite payload based on a spatial heterodyne spectrometer for atmospheric temperature measurements in the mesosphere and lower thermosphere

A highly miniaturized limb sounder for the observation of the O-2 A-band to derive temperatures in the mesosphere and lower thermosphere is presented. The instrument consists of a monolithic spatial heterodyne spectrometer (SHS), which is able to resolve the rotational structure of the R-branch of that band. The relative intensities of the emission lines follow a Boltzmann distribution and the ratio of the lines can be used to derive the kinetic temperature. The SHS operates at a Littrow wavelength of 761.8 nm and heterodynes a wavelength regime between 761.9 and 765.3 nm with a resolving power of about 8000 considering apodization effects. The size of the SHS is 38 x 38 x 27 mm(3) and its acceptance angle is +/- 5 degrees. It has an etendue of 0.01 cm(2) sr. Complemented by front optics with an acceptance angle of +/- 0.65 degrees and detector optics, the entire optical system fits into a volume of about 1.5 L. This allows us to fly this instrument on a 3- or 6-unit CubeSat. The vertical field of view of the instrument is about 60 km at the Earth's limb when operated in a typical low Earth orbit. Integration times to obtain an entire altitude profile of nighttime temperatures are on the order of 1 min for a vertical resolution of 1.5 km and a random noise level of about 1.5 K. Daytime integration times are 1 order of magnitude shorter. This work presents the design parameters of the optics and a radiometric assessment of the instrument. Furthermore, it gives an overview of the required characterization and calibration steps. This includes the characterization of image distortions in the different parts of the optics, visibility, and phase determination as well as flat fielding

Characterisation and testing of CHEC-M—A camera prototype for the small-sized telescopes of the Cherenkov telescope array

The Compact High Energy Camera (CHEC) is a camera design for the Small-Sized Telescopes (SSTs; 4 m diameter mirror) of the Cherenkov Telescope Array (CTA). The SSTs are focused on very-high-energy -ray detection via atmospheric Cherenkov light detection over a very large area. This implies many individual units and hence cost-effective implementation, as well as shower detection at large impact distance, and hence large field of view (FoV), and efficient image capture in the presence of large time gradients in the shower image detected by the camera. CHEC relies on dual-mirror optics to reduce the plate-scale and make use of 6 6 mm pixels, leading to a low-cost (150 k€), compact (0.5 m 0.5 m), and light (45 kg) camera with 2048 pixels providing a camera FoV of 9 degrees. The CHEC electronics are based on custom TARGET (TeV array readout with GSa/s sampling and event trigger) application-specific integrated circuits (ASICs) and field programmable gate arrays (FPGAs) sampling incoming signals at a gigasample per second, with flexible camera-level triggering within a single backplane FPGA. CHEC is designed to observe in the -ray energy range of 1–300 TeV, and at impact distances up to 500 m. To accommodate this and provide full flexibility for later data analysis, full waveforms with 96 samples for all 2048 pixels can be read out at rates up to 900 Hz. The first prototype, CHEC-M, based on multi-anode photomultipliers (MAPMs) as photosensors, was commissioned and characterised in the laboratory and during two measurement campaigns on a telescope structure at the Paris Observatory in Meudon. In this paper, the results and conclusions from the laboratory and on-site testing of CHEC-M are presented. They have provided essential input on the system design and on operational and data analysis procedures for a camera of this type. A second full-camera prototype based on Silicon photomultipliers (SiPMs), addressing the drawbacks of CHEC-M identified during the first prototype phase, has already been built and is currently being commissioned and tested in the laboratory