| 1. |
- Haynes, Roger, et al.
(author)
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The 4MOST instrument concept overview
- 2014
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In: Ground-based and Airborne Instrumentation for Astronomy V. - : SPIE. - 0277-786X .- 1996-756X. ; 9147, s. 91476-91476
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Conference paper (peer-reviewed)abstract
- The 4MOST([1]) instrument is a concept for a wide-field, fibre-fed high multiplex spectroscopic instrument facility on the ESO VISTA telescope designed to perform a massive (initially >25x10(6) spectra in 5 years) combined all-sky public survey. The main science drivers are: Gaia follow up of chemo-dynamical structure of the Milky Way, stellar radial velocities, parameters and abundances, chemical tagging; eROSITA follow up of cosmology with x-ray clusters of galaxies, X-ray AGN/galaxy evolution to z similar to 5, Galactic X-ray sources and resolving the Galactic edge; Euclid/LSST/SKA and other survey follow up of Dark Energy, Galaxy evolution and transients. The surveys will be undertaken simultaneously requiring: highly advanced targeting and scheduling software, also comprehensive data reduction and analysis tools to produce high-level data products. The instrument will allow simultaneous observations of similar to 1600 targets at R similar to 5,000 from 390-900nm and similar to 800 targets at R>18,000 in three channels between similar to 395-675nm (channel bandwidth: 45nm blue, 57nm green and 69nm red) over a hexagonal field of view of similar to 4.1 degrees2. The initial 5-year 4MOST survey is currently expect to start in 2020. We provide and overview of the 4MOST systems: opto-mechanical, control, data management and operations concepts; and initial performance estimates.
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| 2. |
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- 2019
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Journal article (peer-reviewed)
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| 3. |
- de Jong, Roelof S., et al.
(author)
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4MOST-4-metre Multi-Object Spectroscopic Telescope
- 2014
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In: Ground-based and Airborne Instrumentation for Astronomy V. - : SPIE. - 0277-786X .- 1996-756X. ; 9147
-
Conference paper (peer-reviewed)abstract
- 4MOST is a wide-field, high-multiplex spectroscopic survey facility under development for the VISTA telescope of the European Southern Observatory (ESO). Its main science drivers are in the fields of galactic archeology, high-energy physics, galaxy evolution and cosmology. 4MOST will in particular provide the spectroscopic complements to the large area surveys coming from space missions like Gaia, eROSITA, Euclid, and PLATO and from ground-based facilities like VISTA, VST, DES, LSST and SKA. The 4MOST baseline concept features a 2.5 degree diameter field-of-view with similar to 2400 fibres in the focal surface that are configured by a fibre positioner based on the tilting spine principle. The fibres feed two types of spectrographs; similar to 1600 fibres go to two spectrographs with resolution R> 5000 (lambda similar to 390-930 nm) and similar to 800 fibres to a spectrograph with R> 18,000 (lambda similar to 392-437 nm & 515-572 nm & 605-675 nm). Both types of spectrographs are fixed-configuration, three-channel spectrographs. 4MOST will have an unique operations concept in which 5 year public surveys from both the consortium and the ESO community will be combined and observed in parallel during each exposure, resulting in more than 25 million spectra of targets spread over a large fraction of the southern sky. The 4MOST Facility Simulator (4FS) was developed to demonstrate the feasibility of this observing concept. 4MOST has been accepted for implementation by ESO with operations expected to start by the end of 2020. This paper provides a top-level overview of the 4MOST facility, while other papers in these proceedings provide more detailed descriptions of the instrument concept[1], the instrument requirements development[2], the systems engineering implementation[3], the instrument model[4], the fibre positioner concepts[5], the fibre feed[6], and the spectrographs[7].
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| 4. |
- Lang, Margareta, et al.
(author)
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Standardised and automated assessment of head computed tomography reliably predicts poor functional outcome after cardiac arrest: a prospective multicentre study
- 2024
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In: Intensive Care Medicine. - : SPRINGER. - 0342-4642 .- 1432-1238.
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Journal article (peer-reviewed)abstract
- Purpose: Application of standardised and automated assessments of head computed tomography (CT) for neuroprognostication after out-of-hospital cardiac arrest. Methods: Prospective, international, multicentre, observational study within the Targeted Hypothermia versus Targeted Normothermia after out-of-hospital cardiac arrest (TTM2) trial. Routine CTs from adult unconscious patients obtained > 48 h <= 7 days post-arrest were assessed qualitatively and quantitatively by seven international raters blinded to clinical information using a pre-published protocol. Grey-white-matter ratio (GWR) was calculated from four (GWR-4) and eight (GWR-8) regions of interest manually placed at the basal ganglia level. Additionally, GWR was obtained using an automated atlas-based approach. Prognostic accuracies for prediction of poor functional outcome (modified Rankin Scale 4-6) for the qualitative assessment and for the pre-defined GWR cutoff < 1.10 were calculated. Results: 140 unconscious patients were included; median age was 68 years (interquartile range [IQR] 59-76), 76% were male, and 75% had poor outcome. Standardised qualitative assessment and all GWR models predicted poor outcome with 100% specificity (95% confidence interval [CI] 90-100). Sensitivity in median was 37% for the standardised qualitative assessment, 39% for GWR-8, 30% for GWR-4 and 41% for automated GWR. GWR-8 was superior to GWR-4 regarding prognostic accuracies, intra- and interrater agreement. Overall prognostic accuracy for automated GWR (area under the curve [AUC] 0.84, 95% CI 0.77-0.91) did not significantly differ from manually obtained GWR. Conclusion: Standardised qualitative and quantitative assessments of CT are reliable and feasible methods to predict poor functional outcome after cardiac arrest. Automated GWR has the potential to make CT quantification for neuroprognostication accessible to all centres treating cardiac arrest patients.
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| 5. |
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| 6. |
- Nguyen, Hugo, et al.
(author)
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Micropropulsion systems research and manufacture in Sweden
- 2003
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In: Proceedings of the 4th Round Table on Micro/Nano Technology for Space, ESTEC, Noordwijk, The Netherlands. - : ESTEC/ESA. ; , s. 476-485
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Conference paper (peer-reviewed)abstract
- Micropropulsion for spacecraft is an enabling technology for many future missions, and may increase the performance and drastically reduce the mass required for advanced propulsion systems. The Swedish activities in micropropulsion at The Angstrom Space Technology Centre (ASTC) are outlined. The research targets two major issues: the development of system parts, and the research into integration techniques and strategies. This paper collects a multitude of devices relevant to the micropropulsion system design, together with representative functional demonstrations. The items are mainly intended for chemical micropropulsion systems or fuel-feed systems for electric propulsion. In particular, gas handling devices, sensors, and actuators are presented. These include silicon nozzles, thin film heaters, suspended microcoil heaters, proportional piezoelectric valves, proportional and isolation valves using phase-change material, thermal throttle flow-regulators, high-pressure regulators, 3D-particle filters, and sensors for strain, pressure, flow, and thrust. Moreover, integration techniques and interface structures are presented, for example low-temperature plasma-assisted silicon wafer bonding, multiwafer bonding, thin film soldering, hermetic electric through-wafer via connections, and multiconnector through-wafer vias. Emphasis is on how these items are designed to allow for system integration in a multiwafer silicon stack, comprising a complete micropropulsion system. In this manner, all items form a parts collection available to the system design. This strategy is exemplified by three micropropulsion systems researched at the ASTC. First, the cold/hot gas micropropulsion system is suitable for small spacecraft or when the demands on stability and pointing precision are extreme. The system performance depends strongly on the use of gas flow control. The complete gas handling system of four independent thrusters is integrated in the assembly of four structured silicon wafers. Each independent thruster contains a proportional valve, sensors for pressure, temperature, and thrust feedback, a converging-diverging micronozzle, and a suspended microcoil heater. The mass of the system is below 60 g. In total, this will provide the spacecraft with a safe, clean, low-powered, redundant, and flexible system for three-axis stabilization and attitude control. Second, a Xenon feed system for ion propulsion is heavily miniaturized using microsystems technology. Basically, a micromachined high-pressure regulator receives the gas from the storage, and the flow is further modulated by a thermally controlled flow restrictor. The flow restrictor microsystem comprises narrow ducts, thin film heaters, suspended parts for heat management, and flow sensors. Hereby, the amount of xenon required by the electric propulsion systems can be promptly delivered. The complete system mass is estimated to 150g. Third, within the EU IST program, the ASTC participates in the development of a micro-pyrotechnic actuator system (Micropyros), suitable for short-duration space propulsion. The Micropyros integrate a full matrix of minute solid combustion rocket engines into panels situated on the spacecraft hull. The thrusters can be individually ignited, and each deliver thrust in the millinewton range. The ASTC focuses on the integration of the propulsion part by low-temperature bonding, and the characterization of the complete system.
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| 7. |
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| 8. |
- Abgrall, N., et al.
(author)
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The large enriched germanium experiment for neutrinoless double beta decay (LEGEND)
- 2017
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In: AIP Conference Proceedings. - : Author(s). - 1551-7616 .- 0094-243X. ; 1894
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Conference paper (peer-reviewed)abstract
- The observation of neutrinoless double-beta decay (0νββ) would show that lepton number is violated, reveal that neu-trinos are Majorana particles, and provide information on neutrino mass. A discovery-capable experiment covering the inverted ordering region, with effective Majorana neutrino masses of 15 - 50 meV, will require a tonne-scale experiment with excellent energy resolution and extremely low backgrounds, at the level of ∼0.1 count /(FWHM·t·yr) in the region of the signal. The current generation 76Ge experiments GERDA and the Majorana Demonstrator, utilizing high purity Germanium detectors with an intrinsic energy resolution of 0.12%, have achieved the lowest backgrounds by over an order of magnitude in the 0νββ signal region of all 0νββ experiments. Building on this success, the LEGEND collaboration has been formed to pursue a tonne-scale 76Ge experiment. The collaboration aims to develop a phased 0νββ experimental program with discovery potential at a half-life approaching or at 1028 years, using existing resources as appropriate to expedite physics results.
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| 9. |
- Abolfathi, Bela, et al.
(author)
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The Fourteenth Data Release of the Sloan Digital Sky Survey : First Spectroscopic Data from the Extended Baryon Oscillation Spectroscopic Survey and from the Second Phase of the Apache Point Observatory Galactic Evolution Experiment
- 2018
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In: Astrophysical Journal Supplement Series. - : IOP Publishing Ltd. - 0067-0049 .- 1538-4365. ; 235:2
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Journal article (peer-reviewed)abstract
- The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) has been in operation since 2014 July. This paper describes the second data release from this phase, and the 14th from SDSS overall (making this Data Release Fourteen or DR14). This release makes the data taken by SDSS-IV in its first two years of operation (2014-2016 July) public. Like all previous SDSS releases, DR14 is cumulative, including the most recent reductions and calibrations of all data taken by SDSS since the first phase began operations in 2000. New in DR14 is the first public release of data from the extended Baryon Oscillation Spectroscopic Survey; the first data from the second phase of the Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE-2), including stellar parameter estimates from an innovative data-driven machine-learning algorithm known as "The Cannon"; and almost twice as many data cubes from the Mapping Nearby Galaxies at APO (MaNGA) survey as were in the previous release (N = 2812 in total). This paper describes the location and format of the publicly available data from the SDSS-IV surveys. We provide references to the important technical papers describing how these data have been taken (both targeting and observation details) and processed for scientific use. The SDSS web site (www.sdss.org) has been updated for this release and provides links to data downloads, as well as tutorials and examples of data use. SDSS-IV is planning to continue to collect astronomical data until 2020 and will be followed by SDSS-V.
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| 10. |
- Abolins, M., et al.
(author)
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The ATLAS Data Acquisition and High Level Trigger system
- 2016
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In: Journal of Instrumentation. - 1748-0221. ; 11
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Journal article (peer-reviewed)abstract
- This paper describes the data acquisition and high level trigger system of the ATLAS experiment at the Large Hadron Collider at CERN, as deployed during Run 1. Data flow as well as control, configuration and monitoring aspects are addressed. An overview of the functionality of the system and of its performance is presented and design choices are discussed.
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