| 1. |
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| 2. |
- Brucalassi, Anna, et al.
(författare)
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Full System Test and early Preliminary Acceptance Europe results for CRIRES
- 2018
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Ingår i: Ground-Based And Airborne Instrumentation For Astronomy VII. - : SPIE. - 9781510619586
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Konferensbidrag (refereegranskat)abstract
- CRIRES+ is the new high-resolution NIR echelle spectrograph intended to be operated at the platform B of VLT Unit telescope UT3. It will cover from Y to M bands (0.95-5.3um) with a spectral resolution of R = 50000 or R = 100000. The main scientific goals are the search of super-Earths in the habitable zone of low-mass stars, the characterisation of transiting planets atmosphere and the study of the origin and evolution of stellar magnetic fields. Based on the heritage of the old adaptive optics (AO) assisted VLT instrument CRIRES, the new spectrograph will present improved optical layout, a new detector system and a new calibration unit providing optimal performances in terms of simultaneous wavelength coverage and radial velocity accuracy (a few m/s). The total observing efficiency will be enhanced by a factor of 10 with respect to CRIRES. An innovative spectro-polarimetry mode will be also offered and a new metrology system will ensure very high system stability and repeatability. Fiinally, the CRIRES+ project will also provide the community with a new data reduction software (DRS) package. CRIRES+ is currently at the initial phase of its Preliminary Acceptance in Europe (PAE) and it will be commissioned early in 2019 at VLT. This work outlines the main results obtained during the initial phase of the full system test at ESO HQ Garching.
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| 3. |
- Callini, Elsa, et al.
(författare)
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Nanostructured materials for solid-state hydrogen storage : A review of the achievement of COST Action MP1103
- 2016
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Ingår i: International journal of hydrogen energy. - : Elsevier. - 0360-3199 .- 1879-3487. ; 41:32, s. 14404-14428
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Tidskriftsartikel (refereegranskat)abstract
- In the framework of the European Cooperation in Science and Technology (COST) Action MP1103 Nanostructured Materials for Solid-State Hydrogen Storage were synthesized, characterized and modeled. This Action dealt with the state of the art of energy storage and set up a competitive and coordinated network capable to define new and unexplored ways for Solid State Hydrogen Storage by innovative and interdisciplinary research within the European Research Area. An important number of new compounds have been synthesized: metal hydrides, complex hydrides, metal halide ammines and amidoboranes. Tuning the structure from bulk to thin film, nanoparticles and nanoconfined composites improved the hydrogen sorption properties and opened the perspective to new technological applications. Direct imaging of the hydrogenation reactions and in situ measurements under operando conditions have been carried out in these studies. Computational screening methods allowed the prediction of suitable compounds for hydrogen storage and the modeling of the hydrogen sorption reactions on mono-, bi-, and three-dimensional systems. This manuscript presents a review of the main achievements of this Action.
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| 4. |
- Dorn, Reinhold J., et al.
(författare)
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CRIRES+ on sky : High spectral resolution at infrared wavelength enabling better science at the ESO VLT
- 2022
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Ingår i: Ground-Based And Airborne Instrumentation For Astronomy IX. - : SPIE - International Society for Optical Engineering. - 9781510653504 - 9781510653498
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Konferensbidrag (refereegranskat)abstract
- CRIRES+ extended the capabilities of CRIRES, the CRyogenic InfraRed Echelle Spectrograph. It transformed this VLT instrument into a cross-dispersed spectrograph to increase the wavelength range that is covered simultaneously by a factor of ten. In addition, a new detector focal plane array of three Hawaii 2RG detectors with a 5.3 mu m cut-off wavelength replaced the existing detectors. Amongst many other improvements a new spectropolarimetric unit was added and the calibration system has been enhanced. The instrument was installed at the VLT on Unit Telescope 3 beginning of 2020 and successfully commissioned and verified for science operations during 2021, partly remote from Europe due to the pandemic. The instrument was subsequently offered to the community from October 2021 onwards. This article describes the performance and capabilities of this development and presents on sky results.
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| 5. |
- Dorn, Reinhold J., et al.
(författare)
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The " plus " for CRIRES : enabling better science at infrared wavelength and high spectral resolution at the ESO VLT
- 2016
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Ingår i: GROUND-BASED AND AIRBORNE INSTRUMENTATION FOR ASTRONOMY VI. - : SPIE. - 9781510601963
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Konferensbidrag (refereegranskat)abstract
- The adaptive optics (AO) assisted CRIRES instrument was a IR (0.92 - 5.2 mu m) high-resolution spectrograph in operation from 2006 to 2014 at the Very Large Telescope (VLT) observatory. CRIRES was a unique instrument, accessing a parameter space (wavelength range and spectral resolution) up to now largely uncharted. It consisted of a single-order spectrograph providing long-slit (40 arcsecond) spectroscopy with a resolving power up to R=100 000. However the setup was limited to a narrow, single-shot, spectral range of about 1/70 of the central wavelength, resulting in low observing efficiency for many scientific programmes requiring a broad spectral coverage. The CRIRES upgrade project, CRIRES, transfouns this VLT instrument into a cross-dispersed spectrograph to increase the simultaneously covered wavelength range by a factor of ten. A new and larger detector focal plane array of three Hawaii 2RG detectors with 5.3 mu m cut-off wavelength will replace the existing detectors. For advanced wavelength calibration, custom-made absorption gas cells and an etalon system will be added. A spectro-polarimetric unit will allow the recording of circular and linear polarized spectra. This upgrade will be supported by dedicated data reduction software allowing the community to take full advantage of the new capabilities. CRIRES has now entered its assembly and integration phase and will return with all new capabilities by the beginning of 2018 to the Very Large Telescope in Chile. This article will provide the reader with an update of the current status of the instrument as well as the remaining steps until final installation at the Paranal Observatory.
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| 6. |
- Follert, Roman, et al.
(författare)
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Characterizing the cross dispersion reflection gratings of CRIRES
- 2016
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Ingår i: Advances In Optical And Mechanical Technologies For Telescopes And Instrumentation Ii. - : SPIE. - 9781510602038 - 9781510602045
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Konferensbidrag (refereegranskat)abstract
- The CRIRES+ project attempts to upgrade the CRIRES instrument into a cross dispersed echelle spectrograph with a simultaneous recording of 8-10 diffraction orders. In order to transform the CRIRES spectrograph into a cross-dispersing instrument, a set of six reflection gratings, each one optimized for one of the wavelength bands CRIRES+ will operate in (YJHKLM), will be used as cross dispersion elements in CRIRES+. Due to the upgrade nature of the project, the choice of gratings depends on the fixed geometry of the instrument. Thus, custom made gratings would be required to achieve the ambitious design goals. Custom made gratings have the disadvantage, though, that they come at an extraordinary price and with lead times of more than 12 months. To mitigate this, a set of off-the-shelf gratings was obtained which had grating parameters very close to the ones being identified as optimal. To ensure that the rigorous specifications for CRIRES+ will be fulfilled, the CRIRES+ team started a collaboration with the Physikalisch-Technische Bundesanstalt Berlin (PTB) to characterize gratings under conditions similar to the operating conditions in CRIRES+ (angle of incidence, wavelength range). The respective test setup was designed in collaboration between PTB and the CRIRES+ consortium. The PTB provided optical radiation sources and calibrated detectors for each wavelength range. With this setup, it is possible to measure the absolute efficiency of the gratings both wavelength dependent and polarization state dependent in a wavelength range from 0.9 mu m to 6 mu m.
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| 7. |
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| 8. |
- Hirscher, Michael, et al.
(författare)
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Materials for hydrogen-based energy storage - past, recent progress and future outlook
- 2020
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Ingår i: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388 .- 1873-4669. ; 827
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Tidskriftsartikel (refereegranskat)abstract
- Globally, the accelerating use of renewable energy sources, enabled by increased efficiencies and reduced costs, and driven by the need to mitigate the effects of climate change, has significantly increased research in the areas of renewable energy production, storage, distribution and end-use. Central to this discussion is the use of hydrogen, as a clean, efficient energy vector for energy storage. This review, by experts of Task 32, Hydrogen-based Energy Storage of the International Energy Agency, Hydrogen TCP, reports on the development over the last 6 years of hydrogen storage materials, methods and techniques, including electrochemical and thermal storage systems. An overview is given on the background to the various methods, the current state of development and the future prospects. The following areas are covered; porous materials, liquid hydrogen carriers, complex hydrides, intermetallic hydrides, electrochemical storage of energy, thermal energy storage, hydrogen energy systems and an outlook is presented for future prospects and research on hydrogen-based energy storage.
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| 9. |
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| 10. |
- Lizon, Jean Louis, et al.
(författare)
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Very accurate cryogenic mechanisms for CRIRES
- 2018
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Ingår i: OPTICAL AND INFRARED INTERFEROMETRY AND IMAGING VI. - : SPIE-INT SOC OPTICAL ENGINEERING. - 9781510619562
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Konferensbidrag (refereegranskat)abstract
- After 5 years of operation on the VLT, a large upgrade of CRIRES (the ESO Cryogenic InfraRed Echelle Spectrograph) was decided mainly in order to increase the efficiency. Using a cross dispersion design allows better wavelength coverage per exposure. This means a complete re-design of the cryogenic pre-optic which were including a pre-dispersion stage with a large prism as dispersive element. The new design requires a move of the entrance slit and associated decker toward the first intermediate focal plane right behind the window. Implement 2 functions with high positioning accuracy in a pre-defined and limited space was a real challenge. The design and the test results recorded in the ESO Cryogenic Test Facility are reported in this paper. The second critical function is the grating wheel which positions the 6 cross disperser gratings into the beam. The paper describes the design of the mechanism which includes a detente system in order to guaranty the 5 arc sec positioning reproducibility requested. The design includes also feedback system, based on switches, in order to ensure that the right grating is in position before starting a long exposure. The paper reports on the tests carried out at cryogenic temperature at the sub-system level. It also includes early performances recorded in the instrument along the first phases of the system test.
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| 11. |
- Lockhart, Matthew, et al.
(författare)
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Novel infrared polarimeter for the ESO CRIRES plus instrument
- 2014
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Ingår i: GROUND-BASED AND AIRBORNE INSTRUMENTATION FOR ASTRONOMY V. - : SPIE. - 9780819496157
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Konferensbidrag (refereegranskat)abstract
- The CRIRES infrared spectrograph at the European Southern Observatory (ESO) Very Large Telescope (VLT) facility will soon receive an upgrade. This upgrade will include the addition of a module for performing high-resolution spectropolarimetry. The polarimetry module will incorporate a novel infrared beamsplitter based on polarization gratings (PGs). The beamsplitter produces a pair of infrared output beams, with opposite circular polarizations, which are then fed into the spectrograph. Visible light passes through the module virtually unaltered and is then available for use by the CRIRES adaptive optics system. We present the design of the polarimetry module and measurements of PG behavior in the 1 to 2.7 mu m wavelength range.
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| 12. |
- Molinari, Alan, et al.
(författare)
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Interface and strain effects on the H-sorption thermodynamics of size-selected Mg nanodots
- 2016
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Ingår i: International journal of hydrogen energy. - : Elsevier BV. - 0360-3199 .- 1879-3487. ; 41:23, s. 9841-9851
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Tidskriftsartikel (refereegranskat)abstract
- This work deals with the thermodynamics of hydride formation in 3-D nanoconfined Mg. Two ensembles of nearly monodisperse Mg nanodots (NDs) with different diameters (60 and 320 nm), were grown by the template nanopatterning method, using ultra-thin alumina membranes (UTAMs) with ordered porosity as evaporation masks. Multilayer NDs consisting of 30 nm Mg, 5 nm Ti and 5 nm Pd were deposited on UTAM-coated glass substrates by molecular beam epitaxy. The lateral surface of the NDs is constituted by native MgO. The morphology of the NDs was characterized by field emission scanning electron microscopy and atomic force microscopy. Hydride formation and decomposition was studied at low temperature (363-393 K) by means of optical hydrogenography. Compared to bulk Mg, the plateau pressure for hydrogen absorption in NDs exhibits an upward shift, which is larger for small NDs. Differently, the desorption plateau pressure is almost the same for the two NDs size and is lower than for bulk Mg. These hydrogen sorption features are discussed in the frame of a model that takes into account both interface energy and elastic strain energy in the constrained nanodots. The onset of plastic deformation, marked by a high pressure hysteresis between hydrogen absorption and desorption isotherms, limits the extent of hydride destabilization that can be achieved by elastic strain engineering.
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| 13. |
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| 14. |
- Pasquini, Chiara, et al.
(författare)
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Operando tracking of oxidation-state changes by coupling electrochemistry with time-resolved X-ray absorption spectroscopy demonstrated for water oxidation by a cobalt-based catalyst film
- 2021
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Ingår i: Analytical and Bioanalytical Chemistry. - : Springer Nature. - 1618-2642 .- 1618-2650. ; 413:21, s. 5395-5408
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Tidskriftsartikel (refereegranskat)abstract
- Transition metal oxides are promising electrocatalysts for water oxidation, i.e., the oxygen evolution reaction (OER), which is critical in electrochemical production of non-fossil fuels. The involvement of oxidation state changes of the metal in OER electrocatalysis is increasingly recognized in the literature. Tracing these oxidation states under operation conditions could provide relevant information for performance optimization and development of durable catalysts, but further methodical developments are needed. Here, we propose a strategy to use single-energy X-ray absorption spectroscopy for monitoring metal oxidation-state changes during OER operation with millisecond time resolution. The procedure to obtain time-resolved oxidation state values, using two calibration curves, is explained in detail. We demonstrate the significance of this approach as well as possible sources of data misinterpretation. We conclude that the combination of X-ray absorption spectroscopy with electrochemical techniques allows us to investigate the kinetics of redox transitions and to distinguish the catalytic current from the redox current. Tracking of the oxidation state changes of Co ions in electrodeposited oxide films during cyclic voltammetry in neutral pH electrolyte serves as a proof of principle.
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| 15. |
- Pasquini, Luca, et al.
(författare)
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Magnesium- and intermetallic alloys-based hydrides for energy storage : modelling, synthesis and properties
- 2022
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Ingår i: Progress in Energy. - : Institute of Physics Publishing (IOPP). - 2516-1083. ; 4:3
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Forskningsöversikt (refereegranskat)abstract
- Hydrides based on magnesium and intermetallic compounds provide a viable solution to the challenge of energy storage from renewable sources, thanks to their ability to absorb and desorb hydrogen in a reversible way with a proper tuning of pressure and temperature conditions. Therefore, they are expected to play an important role in the clean energy transition and in the deployment of hydrogen as an efficient energy vector. This review, by experts of Task 40 'Energy Storage and Conversion based on Hydrogen' of the Hydrogen Technology Collaboration Programme of the International Energy Agency, reports on the latest activities of the working group 'Magnesium- and Intermetallic alloys-based Hydrides for Energy Storage'. The following topics are covered by the review: multiscale modelling of hydrides and hydrogen sorption mechanisms; synthesis and processing techniques; catalysts for hydrogen sorption in Mg; Mg-based nanostructures and new compounds; hydrides based on intermetallic TiFe alloys, high entropy alloys, Laves phases, and Pd-containing alloys. Finally, an outlook is presented on current worldwide investments and future research directions for hydrogen-based energy storage.
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| 16. |
- Piskunov, Nikolai, professor, 1957-, et al.
(författare)
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A unique infrared spectropolarimetric unit for CRIRES
- 2018
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Ingår i: GROUND-BASED AND AIRBORNE INSTRUMENTATION FOR ASTRONOMY VII. - : SPIE-INT SOC OPTICAL ENGINEERING. - 9781510619586
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Konferensbidrag (refereegranskat)abstract
- High-resolution infrared spectropolarimetry has many science applications in astrophysics. One of them is measuring weak magnetic fields using the Zeeman effect. Infrared domain is particularly advantageous as Zeeman splitting of spectral lines is proportional to the square of the wavelength while the intrinsic width of the line cores increases only linearly. Important science cases include detection and monitoring of global magnetic fields on solar-type stars, study of the magnetic field evolution from stellar formation to the final stages of the stellar life with massive stellar winds, and the dynamo mechanism operation across the boundary between fully-and partially-convective stars. CRIRES+ (the CRIRES upgrade project) includes a novel spectropolarimetric unit (SPU) based on polarization gratings. The novel design allows to perform beam-splitting very early in the optical path, directly after the tertiary mirror of the telescope (the ESO Very Large Telescope, VLT), minimizing instrumental polarization. The new SPU performs polarization beam-splitting in the near-infrared while keeping the telescope beam mostly unchanged in the optical domain, making it compatible with the adaptive optics system of the CRIRES+ instrument. The SPU consists of four beam-splitters optimized for measuring circular and linear polarization of spectral lines in YJ and HK bands. The SPU can perform beam switching allowing to correct for throughput in each beam and for variations in detector pixel sensitivity. Other new features of CRIRES+, such as substantially increased wavelength coverage, stability and advanced data reduction pipeline will further enhance the sensitivity of the polarimetric mode. The combination of the SPU, CRIRES+ and the VLT is a unique facility for making major progress in understanding stellar activity. In this article we present the design of the SPU, laboratory measurements of individual components and of the whole unit as well as the performance prediction for the operation at the VLT.
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