| 1. |
- Batani, D., et al.
(författare)
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Effects of laser prepulse on proton generation
- 2010
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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. ; 620:1, s. 76-82
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Konferensbidrag (refereegranskat)abstract
- Low-intensity laser prepulse ( < 10(13) W/cm(2), ns duration) are a major issue in experiments on laser-generation of protons, often limiting the performances of proton sources produced by high-intensity lasers (approximate to 10(19) W/cm(2), ps or fs duration) Several effects are associated to the prepulse and are discussed in this contribution: i) Destruction of thin foil targets by the shock generated by the laser prepulse ii) Creation of preplasma on target front side affecting laser absorption iii) Deformation of target rear side iv) Whole displacement of thin foil targets affecting focusing condition In particular, we show that under oblique high-intensity irradiation and for low prepulse intensities, the proton beam is directed away from the target normal. Deviation is towards the laser forward direction, with an angle that increases with the level and duration of the ASE pedestal. Also, for a given laser pulse, beam deviation increases with proton energy. The observations are discussed in terms of Target Normal Sheath Acceleration, in combination with a laser-controllable shock wave locally deforming the target surface. (C) 2010 Elsevier B.V. All rights reserved.
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| 2. |
- Batani, D., et al.
(författare)
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Effects of laser prepulse on proton generation
- 2010
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Ingår i: Radiation Effects and Defects in Solids. - : Informa UK Limited. - 1042-0150 .- 1029-4953. ; 165:6-10, s. 794-802
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Konferensbidrag (refereegranskat)abstract
- Prepulse is a major issue for laser generation of protons, often limiting the performances of laser sources. Here, we show the use of prepulse (1013W/cm2, ns duration) to actively manipulate the proton beam direction. Under oblique high-intensity irradiation (approximate to 1019W/cm2, ps duration) of the thin foil target, and for low prepulse intensities, the proton beam is directed away from the ounperturbedo target normal. Observations are discussed in terms of target normal sheath acceleration, in combination with a laser-controllable shock locally deforming the target surface.
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| 3. |
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| 4. |
- Bergström, Markus, et al.
(författare)
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The Settlement
- 2019
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Ingår i: Verksmidjan art space in Hjalteyri, Iceland (Permanent installation) N4 regional television.
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Konstnärligt arbete (övrigt vetenskapligt/konstnärligt)abstract
- A one week workshop and performance leading up to a permanent installation of a prototyped, functional living space within a former fish factory. Initiated by french artist Sonia Levy, director of Verksmidjan Gustav Geir Bollason and myself. Carried out in all by 13 participants (stated above).
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| 5. |
- Bivik Stadler, Caroline, 1986-, et al.
(författare)
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Proactive Construction of an Annotated Imaging Database for Artificial Intelligence Training
- 2021
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Ingår i: Journal of digital imaging. - : Springer-Verlag New York. - 0897-1889 .- 1618-727X. ; 34, s. 105-115
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Tidskriftsartikel (refereegranskat)abstract
- Artificial intelligence (AI) holds much promise for enabling highly desired imaging diagnostics improvements. One of the most limiting bottlenecks for the development of useful clinical-grade AI models is the lack of training data. One aspect is the large amount of cases needed and another is the necessity of high-quality ground truth annotation. The aim of the project was to establish and describe the construction of a database with substantial amounts of detail-annotated oncology imaging data from pathology and radiology. A specific objective was to be proactive, that is, to support undefined subsequent AI training across a wide range of tasks, such as detection, quantification, segmentation, and classification, which puts particular focus on the quality and generality of the annotations. The main outcome of this project was the database as such, with a collection of labeled image data from breast, ovary, skin, colon, skeleton, and liver. In addition, this effort also served as an exploration of best practices for further scalability of high-quality image collections, and a main contribution of the study was generic lessons learned regarding how to successfully organize efforts to construct medical imaging databases for AI training, summarized as eight guiding principles covering team, process, and execution aspects.
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| 6. |
- Bossini-Castillo, Lara, et al.
(författare)
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A replication study confirms the association of TNFSF4 (OX40L) polymorphisms with systemic sclerosis in a large European cohort
- 2011
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Ingår i: Annals of the Rheumatic Diseases. - : BMJ. - 1468-2060 .- 0003-4967. ; 70:4, s. 638-641
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Tidskriftsartikel (refereegranskat)abstract
- Objectives The aim of this study was to confirm the influence of TNFSF4 polymorphisms on systemic sclerosis (SSc) susceptibility and phenotypic features. Methods A total of 8 European populations of Caucasian ancestry were included, comprising 3014 patients with SSc and 3125 healthy controls. Four genetic variants of TNFSF4 gene promoter (rs1234314, rs844644, rs844648 and rs12039904) were selected as genetic markers. Results A pooled analysis revealed the association of rs1234314 and rs12039904 polymorphisms with SSc (OR 1.15, 95% CI 1.02 to 1.31; OR 1.18, 95% CI 1.08 to 1.29, respectively). Significant association of the four tested variants with patients with limited cutaneous SSc (lcSSc) was revealed (rs1234314 OR 1.22, 95% CI 1.07 to 1.38; rs844644 OR 0.91, 95% CI 0.83 to 0.99; rs844648 OR 1.10, 95% CI 1.01 to 1.20 and rs12039904 OR 1.20, 95% CI 1.09 to 1.33). Association of rs1234314, rs844648 and rs12039904 minor alleles with patients positive for anti-centromere antibodies (ACA) remained significant (OR 1.23, 95% CI 1.10 to 1.37; OR 1.12, 95% CI 1.01 to 1.25; OR 1.22, 95% CI 1.07 to 1.38, respectively). Haplotype analysis confirmed a protective haplotype associated with SSc, lcSSc and ACA positive subgroups (OR 0.88, 95% CI 0.82 to 0.96; OR 0.88, 95% CI 0.80 to 0.96; OR 0.86, 95% CI 0.77 to 0.97, respectively) and revealed a new risk haplotype associated with the same groups of patients (OR 1.14, 95% CI 1.03 to 1.26; OR 1.20, 95% CI 1.08 to 1.35; OR 1.23, 95% CI 1.07 to 1.42, respectively). Conclusions The data confirm the influence of TNFSF4 polymorphisms in SSc genetic susceptibility, especially in subsets of patients positive for lcSSc and ACA.
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| 7. |
- Carroll, DC, et al.
(författare)
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Active manipulation of the spatial energy distribution of laser-accelerated proton beams
- 2007
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Ingår i: Physical Review E (Statistical, Nonlinear, and Soft Matter Physics). - 1539-3755. ; 76:065401(R), s. 1-065401
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Tidskriftsartikel (refereegranskat)abstract
- The spatial energy distributions of beams of protons accelerated by ultrahigh intensity (>10^19 W/cm2) picosecond laser pulse interactions with thin foil targets are investigated. Using separate, low intensity (<10^13 W/cm2) nanosecond laser pulses, focused onto the front surface of the target foil prior to the arrival of the high intensity pulse, it is demonstrated that the proton beam profile can be actively manipulated. In particular, results obtained with an annular intensity distribution at the focus of the low intensity beam are presented, showing smooth proton beams with a sharp circular boundary at all energies, which represents a significant improvement in the beam quality compared to irradiation with the picosecond beam alone.
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| 8. |
- Carroll, D. C., et al.
(författare)
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A modified Thomson parabola spectrometer for high resolution multi-MeV ion measurements-Application to laser-driven ion acceleration
- 2010
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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. ; 620:1, s. 23-27
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Konferensbidrag (refereegranskat)abstract
- A novel Thomson parabola ion spectrometer design is presented, in which a gradient electric field configuration is employed to enable a compact design capable of high resolution measurements of ion energy and charge-to-mass ratio. Practical issues relating to the use of the spectrometer for measurement of ion acceleration in high-power laser-plasma experiments are discussed. Example experimental results for ion acceleration from petawatt-class laser interactions with thin gold target foils are presented. (C) 2010 Elsevier B.V. All rights reserved.
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| 9. |
- Carroll, David C., et al.
(författare)
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Dynamic control and enhancement of laser-accelerated protons using multiple laser pulses
- 2009
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Ingår i: Comptes Rendus. Physique. - : Elsevier BV. - 1631-0705. ; 10:2-3, s. 188-196
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Tidskriftsartikel (refereegranskat)abstract
- The use of schemes involving multiple laser pulses to enhance and control the properties of beams of protons accelerated in ultra-intense laser irradiation of planar foil targets is discussed. Specifically, the schemes include the use of a second laser pulse to produce and control preplasma expansion of the target to enhance energy coupling to the proton beam; the use of a second laser pulse to drive shock deformation of the target to change the direction of the proton beam; and a scheme involving dual high intensity laser pulses to change the properties of the sheath field, with the aim of modifying the proton energy spectrum. An overview of our recent experimental and theoretical results is given. The overall aim of this work is to determine the extent to which the properties of the sheath-accelerated proton beam can be optically controlled, to enable beam delivery at high repetition rates. To cite this article: D.C. Carroll et al., C. R. Physique 10 (2009). (C) 2009 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.
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| 10. |
- Cassou, K., et al.
(författare)
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Optimization toward a high-average-brightness soft-x-ray laser pumped at grazing incidence
- 2007
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Ingår i: Optics Letters. - 0146-9592. ; 32:2, s. 139-141
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Tidskriftsartikel (refereegranskat)abstract
- We report the near-field imaging characterization of a 10 Hz Ni-like 18.9 nm molybdenum soft-x-ray laser pumped in a grazing incidence pumping (GRIP) geometry with a table-top laser driver. We investigate the effect of varying the GRIP angle on the spatial behavior of the soft-x-ray laser source. After multiparameter optimization, we were able to find conditions to generate routinely a high-repetition-rate soft-x-ray laser with an energy level of up to 3 mu J/pulse and to 6 x 10(17) photons/s/mm(2)/mrad(2)/(0.1% bandwidth) average brightness and 1 x 10(28) photons/s/mm(2)/mrad(2)/(0.1% bandwidth) peak brightness. (c) 2006 Optical Society of America.
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