| 1. |
- Correa, J., et al.
(författare)
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On the Charge Collection Efficiency of the PERCIVAL Detector
- 2016
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Ingår i: Journal of Instrumentation. - : IOP. - 1748-0221. ; 11:12
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Tidskriftsartikel (refereegranskat)abstract
- The PERCIVAL soft X-ray imager is being developed by DESY, RAL, Elettra, DLS, and PAL to address the challenges at high brilliance Light Sources such as new-generation Synchrotrons and Free Electron Lasers. Typical requirements for detector systems at these sources are high frame rates, large dynamic range, single-photon counting capability with low probability of false positives, high quantum efficiency, and (multi)-mega-pixel arrangements. PERCIVAL is a monolithic active pixel sensor, based on CMOS technology. It is designed for the soft X-ray regime and, therefore, it is post-processed in order to achieve high quantum efficiency in its primary energy range (250 eV to 1 keV) . This work will report on the latest experimental results on charge collection efficiency obtained for multiple back-side-illuminated test sensors during two campaigns, at the P04 beam-line at PETRA III, and the CiPo beam-line at Elettra, spanning most of the primary energy range as well as testing the performance for photon-energies below 250 eV . In addition, XPS surface analysis was used to cross-check the obtained results.
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| 2. |
- Khromova, A., et al.
(författare)
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Report on recent results of the PERCIVAL soft X-ray imager
- 2016
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Ingår i: Journal of Instrumentation. - : IOP. - 1748-0221. ; 11:November
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Tidskriftsartikel (refereegranskat)abstract
- The PERCIVAL (Pixelated Energy Resolving CMOS Imager, Versatile And Large) soft X-ray 2D imaging detector is based on stitched, wafer-scale sensors possessing a thick epi-layer, which together with back-thinning and back-side illumination yields elevated quantum efficiency in the photon energy range of 125–1000 eV. Main application fields of PERCIVAL are foreseen in photon science with FELs and synchrotron radiation. This requires high dynamic range up to 105 ph @ 250 eV paired with single photon sensitivity with high confidence at moderate frame rates in the range of 10–120 Hz. These figures imply the availability of dynamic gain switching on a pixel-by-pixel basis and a highly parallel, low noise analog and digital readout, which has been realized in the PERCIVAL sensor layout. Different aspects of the detector performance have been assessed using prototype sensors with different pixel and ADC types. This work will report on the recent test results performed on the newest chip prototypes with the improved pixel and ADC architecture. For the target frame rates in the 10–120 Hz range an average noise floor of 14e− has been determined, indicating the ability of detecting single photons with energies above 250 eV. Owing to the successfully implemented adaptive 3-stage multiple-gain switching, the integrated charge level exceeds 4 centerdot 106 e− or 57000 X-ray photons at 250 eV per frame at 120 Hz. For all gains the noise level remains below the Poisson limit also in high-flux conditions. Additionally, a short overview over the updates on an oncoming 2 Mpixel (P2M) detector system (expected at the end of 2016) will be reported.
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| 3. |
- Wunderer, C. B., et al.
(författare)
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Detector developments at DESY
- 2016
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Ingår i: Journal of Synchrotron Radiation. - 0909-0495 .- 1600-5775. ; 23, s. 111-117
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Tidskriftsartikel (refereegranskat)abstract
- With the increased brilliance of state-of-the-art synchrotron radiation sources and the advent of free-electron lasers (FELs) enabling revolutionary science with EUV to X-ray photons comes an urgent need for suitable photon imaging detectors. Requirements include high frame rates, very large dynamic range, single-photon sensitivity with low probability of false positives and (multi)-megapixels. At DESY, one ongoing development project-in collaboration with RAL/STFC, Elettra Sincrotrone Trieste, Diamond, and Pohang Accelerator Laboratory-is the CMOS-based soft X-ray imager PERCIVAL. PERCIVAL is a monolithic active-pixel sensor back-thinned to access its primary energy range of 250 eV to 1 keV with target efficiencies above 90%. According to preliminary specifications, the roughly 10 cm × 10 cm, 3.5k × 3.7k monolithic sensor will operate at frame rates up to 120 Hz (commensurate with most FELs) and use multiple gains within 27 μm pixels to measure 1 to ∼ 100000 (500 eV) simultaneously arriving photons. DESY is also leading the development of the AGIPD, a high-speed detector based on hybrid pixel technology intended for use at the European XFEL. This system is being developed in collaboration with PSI, University of Hamburg, and University of Bonn. The AGIPD allows singlepulse imaging at 4.5 MHz frame rate into a 352-frame buffer, with a dynamic range allowing single-photon detection and detection of more than 10000 photons at 12.4 keV in the same image. Modules of 65k pixels each are configured to make up (multi)megapixel cameras. This review describes the AGIPD and the PERCIVAL concepts and systems, including some recent results and a summary of their current status. It also gives a short overview over other FEL-relevant developments where the Photon Science Detector Group at DESY is involved. © 2016 International Union of Crystallography.
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| 4. |
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| 5. |
- Marras, A., et al.
(författare)
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Experimental characterization of the PERCIVAL soft X-ray detector
- 2016
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Ingår i: 2015 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2015. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781467398626
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Considerable interest has been manifested for the use of high-brilliance X-ray synchrotron sources and X-ray Free-Electron Lasers for the investigation of samples.
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| 6. |
- Haider, Usman, et al.
(författare)
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Modular Exo-Legs For Mobility Of Elderly Persons
- 2016
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Ingår i: Advances in Cooperative Robotics. - Singapore : WORLD SCIENTIFIC. - 9789813149120 - 9789813149144 ; , s. 851-859
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The paper presents details of the AAL Call 4 EXO-LEGS project aimed at developing and testing lower body assistive exoskeletons to help elderly persons perform daily living activities independently such as stable standing, sit-to-stand transfers, and straight walking. The key components needed have been realized using mobility requirements and design preferences provided by an end-user group comprising 117 members via 5 surveys. Modular human-centric concepts are followed for mechanical design, sensing, and actuation, system integration, etc., to realize a BASIC exoskeleton prototype able to provide up to 30% power to assist the human perform the intended motions. Two ethical approvals have been obtained to involve end-users in the research, development, and test phases of the project. To date, 5 test subjects have tested the exoskeleton prototype in walking and sit-to-stand test; summary results are presented in this paper
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| 7. |
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| 8. |
- Lozano, Rodrigo, et al.
(författare)
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Connecting Competences and Pedagogical Approaches for Sustainable Development in Higher Education : A Literature Review and Framework Proposal
- 2017
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Ingår i: Sustainability. - : MDPI. - 2071-1050. ; 9:10
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Forskningsöversikt (refereegranskat)abstract
- Research into and practice of Higher Education for Sustainable Development (HESD) have been increasing during the last two decades. These have focused on providing sustainability education to future generations of professionals. In this context, there has been considerable progress in the incorporation of SD in universities’ curricula. Most of these efforts have focussed on the design and delivery of sustainability-oriented competences. Some peer-reviewed articles have proposed different pedagogical approaches to better deliver SD in these courses; however, there has been limited research on the connection between how courses are delivered (pedagogical approaches) and how they may affect sustainability competences. This paper analyses competences and pedagogical approaches, using hermeneutics to connect these in a framework based on twelve competences and twelve pedagogical approaches found in the literature. The framework connects the course aims to delivery in HESD by highlighting the connections between pedagogical approaches and competences in a matrix structure. The framework is aimed at helping educators in creating and updating their courses to provide a more complete, holistic, and systemic sustainability education to future leaders, decision makers, educators, and change agents. To better develop mind-sets and actions of future generations, we must provide students with a complete set of sustainability competences.
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