| 1. |
- Akkoyun, S., et al.
(författare)
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AGATA - Advanced GAmma Tracking Array
- 2012
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Ingår i: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. - : Elsevier BV. - 0168-9002 .- 0167-5087 .- 1872-9576. ; 668, s. 26-58
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Tidskriftsartikel (refereegranskat)abstract
- The Advanced GAmma Tracking Array (AGATA) is a European project to develop and operate the next generation γ-ray spectrometer. AGATA is based on the technique of γ-ray energy tracking in electrically segmented high-purity germanium crystals. This technique requires the accurate determination of the energy, time and position of every interaction as a γ ray deposits its energy within the detector volume. Reconstruction of the full interaction path results in a detector with very high efficiency and excellent spectral response. The realisation of γ-ray tracking and AGATA is a result of many technical advances. These include the development of encapsulated highly segmented germanium detectors assembled in a triple cluster detector cryostat, an electronics system with fast digital sampling and a data acquisition system to process the data at a high rate. The full characterisation of the crystals was measured and compared with detector- response simulations. This enabled pulse-shape analysis algorithms, to extract energy, time and position, to be employed. In addition, tracking algorithms for event reconstruction were developed. The first phase of AGATA is now complete and operational in its first physics campaign. In the future AGATA will be moved between laboratories in Europe and operated in a series of campaigns to take advantage of the different beams and facilities available to maximise its science output. The paper reviews all the achievements made in the AGATA project including all the necessary infrastructure to operate and support the spectrometer. © 2011 Elsevier B.V. All rights reserved.
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| 2. |
- Valiente-Dobon, J. J., et al.
(författare)
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Conceptual design of the AGATA 2 pi array at LNL
- 2023
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 1049
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Tidskriftsartikel (refereegranskat)abstract
- The Advanced GAmma Tracking Array (AGATA) has been installed at Laboratori Nazionali di Legnaro (LNL), Italy. In this installation, AGATA will consist, at the beginning, of 13 AGATA triple clusters (ATCs) with an angular coverage of 1n,and progressively the number of ATCs will increase up to a 2 pi angular coverage. This setup will exploit both stable and radioactive ion beams delivered by the Tandem-PIAVE-ALPI accelerator complex and the SPES facility. The new implementation of AGATA at LNL will be used in two different configurations, firstly one coupled to the PRISMA large-acceptance magnetic spectrometer and lately a second one at Zero Degrees, along the beam line. These two configurations will allow us to cover a broad physics program, using different reaction mechanisms, such as Coulomb excitation, fusion-evaporation, transfer and fission at energies close to the Coulomb barrier. These setups have been designed to be coupled with a large variety of complementary detectors such as charged particle detectors, neutron detectors, heavy-ion detectors, high-energy gamma-ray arrays, cryogenic and gasjet targets and the plunger device for lifetime measurements. We present in this paper the conceptual design, characteristics and performance figures of this implementation of AGATA at LNL.
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| 3. |
- Kahnt, Maik, et al.
(författare)
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Multi-slice ptychography enables high-resolution measurements in extended chemical reactors
- 2021
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Ptychographic X-ray microscopy is an ideal tool to observe chemical processes under in situ conditions. Chemical reactors, however, are often thicker than the depth of field, limiting the lateral spatial resolution in projection images. To overcome this limit and reach higher lateral spatial resolution, wave propagation within the sample environment has to be taken into account. Here, we demonstrate this effect recording a ptychographic projection of copper(I) oxide nanocubes grown on two sides of a polyimide foil. Reconstructing the nanocubes using the conventional ptychographic model shows the limitation in the achieved resolution due to the thickness of the foil. Whereas, utilizing a multi-slice approach unambiguously separates two sharper reconstructions of nanocubes on both sides of the foil. Moreover, we illustrate how ptychographic multi-slice reconstructions are crucial for high-quality imaging of chemical processes by ex situ studying copper(I) oxide nanocubes grown on the walls of a liquid cell.
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| 4. |
- Lindström, Åke, et al.
(författare)
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Jordbruksfåglar och småbiotoper – en pilotstudie
- 2015
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- År 2009 startade åtta länsstyrelser (i Stockholms, Uppsala, Södermanlands, Östergötlands, Jönköpings, Skåne, Örebro och Västmanlands län) miljöövervakning av småbiotoper i och i anslutning till åkermark med Sveriges lantbruksuniversitet som utförare. Övervakningen har utförts i ett stickprov inom 3x3 km stora landskapsrutor. Stickprovet sammanfaller med fågelinventeringar inom Svensk fågeltaxering som koordineras av Lunds universitet. Sedan länge har många av jordbruksfåglarna minskat, både i Sverige och i Europa. Resultaten från Svensk fågeltaxering visar att det gått extra dåligt för de fåglar som är knutna till småbiotoper. Den regionala miljöövervakningen av småbiotoper ger värdefulla möjligheter att följa förändringar i mängden småbiotoper parallellt med förändringar i antalet fåglar. I denna storskaliga pilotstudie har sammanlagt 100 fågelrutter inom Svensk fågeltaxering, så kallade standardrutter, jämförts med detaljerade uppgifter om viktiga habitatkaraktärer från den regionala miljöövervakningen av småbiotoper. Hypotesen har varit att antalet arter och individer av typiska jordbruksfåglar generellt ökar med mängden biotoper i jordbrukslandskapet, samt att antalet individer av arter beroende av småbiotoper specifikt ökar med mängden tillgängliga småbiotoper. Resultaten från projektet visar glädjande att det är flera småbiotopsvariabler som utöver mängden åkermark hjälper till att förklara de olika arternas förekomst. Det skulle dock behövas mer analyser för att detaljerna i resultaten, särskilt detaljerna för varje art, kan diskuteras riktigt grundligt. Det viktigaste framöver kommer också vara att förklara hur förändringar i biotopförekomster påverkar förändringar i fågelförekomsten, något som det kommer att finnas utmärkta data för inom några år om fågeltaxeringen och småbiotopsövervakningen fortsätter.
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| 5. |
- Lyubomirskiy, Mikhail, et al.
(författare)
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Multi-beam X-ray ptychography using coded probes for rapid non-destructive high resolution imaging of extended samples
- 2022
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Imaging large areas of a sample non-destructively and with high resolution is of great interest for both science and industry. For scanning coherent X-ray diffraction microscopy, i. e., ptychography, the achievable scan area at a given spatial resolution is limited by the coherent photon flux of modern X-ray sources. Multibeam X-ray ptychography can improve the scanning speed by scanning the sample with several parallel mutually incoherent beams, e. g., generated by illuminating multiple focusing optics in parallel by a partially coherent beam. The main difficulty with this scheme is the robust separation of the superimposed signals from the different beams, especially when the beams and the illuminated sample areas are quite similar. We overcome this difficulty by encoding each of the probing beams with its own X-ray phase plate. This helps the algorithm to robustly reconstruct the multibeam data. We compare the coded multibeam scans to uncoded multibeam and single beam scans, demonstrating the enhanced performance on a microchip sample with regular and repeating structures.
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| 6. |
- Lyubomirskiy, Mikhail, et al.
(författare)
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Planar refractive lenses made of SiC for high intensity nanofocusing
- 2021
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Ingår i: Optics Express. - 1094-4087. ; 29:9, s. 14025-14032
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Tidskriftsartikel (refereegranskat)abstract
- We report on the manufacturing and testing of the first nanofocusing refractive lenses made of single-crystal silicon carbide. We introduce the fabrication process based on lithography, followed by deep isotropic etching. The lenses were characterized at the energy of 12 keV at the beamline P06 of the synchrotron radiation source PETRA III. A focal spot of 186 nm x 275 nm has been achieved with a lens working distance of 29 mm.
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| 7. |
- Parfeniukas, Karolis, et al.
(författare)
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Improved tungsten nanofabrication for hard X-ray zone plates
- 2016
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Ingår i: Microelectronic Engineering. - : Elsevier BV. - 0167-9317 .- 1873-5568. ; 152, s. 6-9
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Tidskriftsartikel (refereegranskat)abstract
- We present an improved nanofabrication method of high aspect ratio tungsten structures for use in high efficiency nanofocusing hard X-ray zone plates. A ZEP 7000 electron beam resist layer used for patterning is cured by a second, much larger electron dose after development. The curing step improves pattern transfer fidelity into a chromium hard mask by reactive ion etching using Cl2/O2 chemistry. The pattern can then be transferred into an underlying tungsten layer by another reactive ion etching step using SF6/O2. A 630 nm-thick tungsten zone plate with smallest line width of 30 nm was fabricated using this method and characterized. At 8.2 keV photon energy the device showed an efficiency of 2.2% with a focal spot size at the diffraction limit, measured at Diamond Light Source I-13-1 beamline.
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| 8. |
- Reimer, M., et al.
(författare)
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Interactive effects of subsidiary crops and weed pressure in the transition period to non-inversion tillage, a case study of six sites across northern and central Europe
- 2019
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Ingår i: Agronomy. - : MDPI AG. - 2073-4395. ; 9:9
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Tidskriftsartikel (refereegranskat)abstract
- Reducing soil tillage can lead to many benefits, but this practice often increases weed abundance and thus the need for herbicides, especially during the transition phase from inversion tillage to non-inversion tillage. We evaluated if subsidiary crops (SCs, e.g., cover crops) can mitigate the effects of non-inversion tillage on weed abundance. Two-year experiments studying SC use, tillage intensity, and nitrogen (N) fertilization level were carried out twice at six sites throughout northern and central Europe. SCs significantly reduced weed cover throughout the intercrop period (−55% to −1% depending on site), but only slightly during the main crops. Overall weed abundance and weed biomass were higher when using non-inversion tillage with SCs compared to inversion tillage without SCs. The effects differed due to site-specific weed pressure and management. With increasing weed pressure, the effect of SCs decreased, and the advantage of inversion over non-inversion tillage increased. N fertilization level did not affect weed abundance. The results suggest that SCs can contribute by controlling weeds but cannot fully compensate for reduced weed control of non-inversion tillage in the transition phase. Using non-inversion tillage together with SCs is primarily recommended in low weed pressure environments. © 2019 by the authors
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| 9. |
- Schropp, Andreas, et al.
(författare)
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PtyNAMi : Ptychographic nano-analytical microscope
- 2020
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Ingår i: Journal of Applied Crystallography. - 0021-8898. ; 53, s. 957-971
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Tidskriftsartikel (refereegranskat)abstract
- Ptychographic X-ray imaging at the highest spatial resolution requires an optimal experimental environment, providing a high coherent flux, excellent mechanical stability and a low background in the measured data. This requires, for example, a stable performance of all optical components along the entire beam path, high temperature stability, a robust sample and optics tracking system, and a scatter-free environment. This contribution summarizes the efforts along these lines to transform the nanoprobe station on beamline P06 (PETRAIII) into the ptychographic nano-analytical microscope (PtyNAMi).
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| 10. |
- Seiboth, Frank, et al.
(författare)
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Aberration Correction for Hard X-ray Focusing at the Nanoscale
- 2017
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Ingår i: Advances in X-Ray/EUV Optics and Components XII. - : SPIE - International Society for Optical Engineering. - 9781510612303 - 9781510612297
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Konferensbidrag (refereegranskat)abstract
- We developed a corrective phase plate that enables the correction of residual aberration in reflective, diffractive, and refractive X-ray optics. The principle is demonstrated on a stack of beryllium compound refractive lenses with a numerical aperture of 0.49 x 10(-3) at three different synchrotron radiation and x-ray free-electron laser facilities. By introducing this phase plate into the beam path, we were able to correct the spherical aberration of the optical system and improve the Strehl ratio of the optics from 0.29(7) to 0.87(5), creating a diffraction-limited, large aperture, nanofocusing optics that is radiation resistant and very compact.
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| 11. |
- Seiboth, Frank, et al.
(författare)
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Perfect X-ray focusing via fitting corrective glasses to aberrated optics
- 2017
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Ingår i: Nature Communications. - : Nature Publishing Group. - 2041-1723. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Due to their short wavelength, X-rays can in principle be focused down to a few nanometres and below. At the same time, it is this short wavelength that puts stringent requirements on X-ray optics and their metrology. Both are limited by today’s technology. In this work, we present accurate at wavelength measurements of residual aberrations of a refractive X-ray lens using ptychography to manufacture a corrective phase plate. Together with the fitted phase plate the optics shows diffraction-limited performance, generating a nearly Gaussian beam profile with a Strehl ratio above 0.8. This scheme can be applied to any other focusing optics, thus solving the X-ray optical problem at synchrotron radiation sources and X-ray free-electron lasers.
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| 12. |
- Wittwer, Felix, et al.
(författare)
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Upscaling of multi-beam x-ray ptychography for efficient x-ray microscopy with high resolution and large field of view
- 2021
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 118:17
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Tidskriftsartikel (refereegranskat)abstract
- Nondestructive imaging with both a large field of view and a high spatial resolution is crucial to understand complex materials and processes in science and technology. X-ray ptychography can provide highest spatial resolution but is limited in the field of view by the acquisition time and coherent flux at modern x-ray sources. By multi-beam ptychography, the sample can be imaged in parallel by several spatially separated and mutually incoherent beams. We have implemented this method using 3D nanoprinted x-ray optics to create tailor-made x-ray multi-beam arrays. The use of 3D printing allows us to create focusing optics with a minimum of nonfunctional support structures. In this way, large sample areas can be efficiently scanned in parallel with up to six illuminating beams.
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| 13. |
- Wittwer, Raphaël A., et al.
(författare)
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Organic and conservation agriculture promote ecosystem multifunctionality
- 2021
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Ingår i: Science Advances. - : American Association for the Advancement of Science (AAAS). - 2375-2548. ; 7:34
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Tidskriftsartikel (refereegranskat)abstract
- Ecosystems provide multiple services to humans. However, agricultural systems are usually evaluated on their productivity and economic performance, and a systematic and quantitative assessment of the multifunctionality of agroecosystems including environmental services is missing. Using a long-term farming system experiment, we evaluated and compared the agronomic, economic, and ecological performance of the most widespread arable cropping systems in Europe: Organic, conservation, and conventional agriculture. We analyzed 43 agroecosystem properties and determined overall agroecosystem multifunctionality. We show that organic and conservation agriculture promoted ecosystem multifunctionality, especially by enhancing regulating and supporting services, including biodiversity preservation, soil and water quality, and climate mitigation. In contrast, conventional cropping showed reduced multifunctionality but delivered highest yield. Organic production resulted in higher economic performance, thanks to higher product prices and additional support payments. Our results demonstrate that different cropping systems provide opposing services, enforcing the productivity-environmental protection dilemma for agroecosystem functioning.
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