| 51. |
- Ball, A., et al.
(författare)
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Design, implementation and first measurements with the Medipix2-MXR detector at the Compact Muon Solenoid experiment
- 2011
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- The Medipix detector is the first device dedicated to measuring mixed-field radiation in the CMS (Compact Muon Solenoid) experiment cavern and able to distinguish between different particle types. Medipix2-MXR chips bump bonded to silicon sensors with various neutron conversion layers developed by the IEAP CTU in Prague were successfully installed for the 2008 LHC start-up in the CMS experimental and services caverns to measure the flux of various particle types, in particular neutrons. They have operated almost continuously during the 2010 run period, and the results shown here are from the proton run between the beginning of July and the end of October 2010. Clear signals are seen and different particle types have been observed during regular LHC luminosity running, and an agreement in the measured flux is found with the simulations. These initial results are promising, and indicate that these devices have the potential for further and future LHC and high energy physics applications as radiation monitoring devices for mixed field environments, including neutron flux monitoring. Further extensions are foreseen in the near future to increase the performance of the detector and its coverage for monitoring in CMS.
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| 52. |
- Banerjee, Sambhasan, et al.
(författare)
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Amyloid fibril structure from the vascular variant of systemic AA amyloidosis
- 2022
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Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Systemic AA amyloidosis is a debilitating protein misfolding disease in humans and animals. In humans, it occurs in two variants that are called 'vascular' and 'glomerular', depending on the main amyloid deposition site in the kidneys. Using cryo electron microscopy, we here show the amyloid fibril structure underlying the vascular disease variant. Fibrils purified from the tissue of such patients are mainly left-hand twisted and contain two non-equal stacks of fibril proteins. They contrast in these properties to the fibrils from the glomerular disease variant which are right-hand twisted and consist of two structurally equal stacks of fibril proteins. Our data demonstrate that the different disease variants in systemic AA amyloidosis are associated with different fibril morphologies.
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| 53. |
- Bech, Martin, et al.
(författare)
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In-vivo dark-field and phase-contrast x-ray imaging.
- 2013
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 3:Nov 13
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Tidskriftsartikel (refereegranskat)abstract
- Novel radiography approaches based on the wave nature of x-rays when propagating through matter have a great potential for improved future x-ray diagnostics in the clinics. Here, we present a significant milestone in this imaging method: in-vivo multi-contrast x-ray imaging of a mouse using a compact scanner. Of particular interest is the enhanced contrast in regions related to the respiratory system, indicating a possible application in diagnosis of lung diseases (e.g. emphysema).
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| 54. |
- Bergmann, U. C., et al.
(författare)
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Beta-decay properties of the neutron-rich Kr94-99 and Xe142-147 isotopes
- 2003
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Ingår i: Nuclear Physics A. - 0375-9474. ; 714:1-2, s. 21-43
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Tidskriftsartikel (refereegranskat)abstract
- Beta-decay half-lives and delayed-neutron emission probabilities of the neutron-rich noble-gas isotopes Kr94-99 and Xe142-147 have been measured at the PSB-ISOLDE facility at CERN. The results are compared to QRPA shell-model predictions and are used in dynamic calculations of r-process abundances of Kr and Xe isotopes. (C) 2002 Elsevier Science B.V. All rights reserved.
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| 55. |
- Brege, Wyatt, et al.
(författare)
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Black hole-neutron star mergers using a survey of finite-temperature equations of state
- 2018
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Ingår i: Physical Review D. - 2470-0010 .- 2470-0029. ; 98:6
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Tidskriftsartikel (refereegranskat)abstract
- Each of the potential signals from a black hole-neutron star merger should contain an imprint of the neutron star equation of state: gravitational waves via its effect on tidal disruption, the kilonova via its effect on the ejecta, and the gamma-ray burst via its effect on the remnant disk. These effects have been studied by numerical simulations and quantified by semianalytic formulas. However, most of the simulations on which these formulas are based use equations of state without finite temperature and composition-dependent nuclear physics. In this paper, we simulate black hole-neutron star mergers varying both the neutron star mass and the equation of state, using three finite-temperature nuclear models of varying stiffness. Our simulations largely vindicate formulas for ejecta properties but do not find the expected dependence of disk mass on neutron star compaction. We track the early evolution of the accretion disk, largely driven by shocking and fallback inflow, and do find notable equation-of-state effects on the structure of this early-time, neutrino-bright disk.
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| 56. |
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| 57. |
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| 58. |
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| 59. |
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| 60. |
- Christlieb, N., et al.
(författare)
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The Hamburg/ESO R-process Enhanced Star survey (HERES). I. Project description, and discovery of two stars with strong enhancements of neutron-capture elements
- 2004
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Ingår i: Astronomy & Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 428:3, s. 1027-1037
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Tidskriftsartikel (refereegranskat)abstract
- We report on a dedicated effort to identify and study metal-poor stars strongly enhanced in r-process elements ([r/Fe]>1 dex; hereafter r-IIstars), the Hamburg/ESO R-process Enhanced Star survey (HERES).Moderate-resolution (∼2 Å) follow-up spectroscopy has been obtained for metal-poor giant candidates selected from the Hamburg/ESO objective-prism survey (HES) as well as the HK survey to identify sharp-lined stars with [Fe/H]<-2.5 dex. For several hundred confirmed metal-poor giants brighter than B∼ 16.5 mag (most of them from theHES), ``snapshot'' spectra (R∼ 20 000; S/N ∼ 30 per pixel) are being obtained with VLT/UVES, with the main aim of finding the 2-3% r-II stars expected to be among them. These are studied in detail by means of higher resolution and higher S/N spectra. In this paper we describe a pilot study based on a set of 35 stars, including 23 from the HK survey,eight from the HES, and four comparison stars. We discovered two new r-II stars, CS 29497-004 ([Eu/Fe]=1.64± 0.22) and CS 29491-069([Eu/Fe]=1.08± 0.23). A first abundance analysis of CS 29497-004 yields that its abundances of Ba to Dy are on average enhanced by 1.5 dex with respect to iron and the Sun and match a scaled solar r-process pattern well, while Th is underabundant relative to that pattern by 0.3dex, which we attribute to radioactive decay. That is, CS 29497-004 seems not to belong to the class of r-process enhanced stars displaying an ``actinide boost'', like CS 31082-001 (Hill et al. 2002), or CS30306-132 (Honda et al. 2004b). The abundance pattern agrees well with predictions of the phenomenological model of Qian & Wasserburg.Based in large part on observations collected at the European Southern Observatory, Paranal, Chile (proposal number 68.B-0320).}
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