| 1. |
- Rofors, E., et al.
(författare)
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Response of a Li-glass/multi-anode photomultiplier detector to focused proton and deuteron beams
- 2020
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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. ; 984
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Tidskriftsartikel (refereegranskat)abstract
- The response of a position-sensitive Li-glass based scintillation detector being developed for thermal-neutron detection with 6 mm position resolution has been investigated using focused beams of 2.5MeV protons and deuterons. The beams were scanned across the detector in 0.5 mm horizontal and vertical steps perpendicular to the beams. Scintillation light was registered using an 8 × 8 pixel multi-anode photomultiplier tube. The signal amplitudes were recorded for each pixel on an event-by-event basis. Several pixels generally registered considerable signals at each beam location. To optimize planned detector operation at the European Spallation Source, the number of pixels above set thresholds was investigated, with the maximization of the single-hit efficiency over the largest possible area as the primary goal. For both beams, at a threshold of ∼50% of the mean of the full-deposition peak, ∼80% of the events were registered in a single pixel, resulting in an effective position resolution of ∼5 mm in X and Y. Lower thresholds resulted in higher pixel multiplicities. These events could also be localized with the same effective position resolution.
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| 2. |
- Dahl, F, et al.
(författare)
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Imaging single DNA molecules for high precision NIPT
- 2018
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Ingår i: Scientific reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 8:1, s. 4549-
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Tidskriftsartikel (refereegranskat)abstract
- Cell-free DNA analysis is becoming adopted for first line aneuploidy screening, however for most healthcare programs, cost and workflow complexity is limiting adoption of the test. We report a novel cost effective method, the Vanadis NIPT assay, designed for high precision digitally-enabled measurement of chromosomal aneuploidies in maternal plasma. Reducing NIPT assay complexity is achieved by using novel molecular probe technology that specifically label target chromosomes combined with a new readout format using a nanofilter to enrich single molecules for imaging and counting without DNA amplification, microarrays or sequencing. The primary objective of this study was to assess the Vanadis NIPT assay with respect to analytical precision and clinical feasibility. Analysis of reference DNA samples indicate that samples which are challenging to analyze with low fetal-fraction can be readily detected with a limit of detection determined at <2% fetal-fraction. In total of 286 clinical samples were analysed and 30 out of 30 pregnancies affected by trisomy 21 were classified correctly. This method has the potential to make cost effective NIPT more widely available with more women benefiting from superior detection and false positive rates.
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| 5. |
- Abdel, Naseem S., et al.
(författare)
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Characterizations of new Delta E detectors for single-ion hit facility
- 2014
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms. - : Elsevier BV. - 0168-583X. ; 318, s. 281-286
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes the performance evaluation of new Delta E detectors to be used as pre-cell hit detectors in living cell irradiation experiments at the Lund Ion Beam Analysis facility (LIBAF). Using these detectors with a thickness down to 4.15 mu m fabricated at Lund University, an experiment was setup in which Delta E-detectors were used together with a stop E-detector in a telescope system under coincidence measurements. The characteristics of Delta E detectors were based on the optimal detection of the passage of 2.55 MeV protons. The results of these tests demonstrate that the detector telescope clearly separates the protons, this due to high signal-to-noise ratio and good energy resolution of the Delta E-detectors. The best performing detector was shown to have a detection efficiency of 95% at thickness of 9.7 mu m. This type of high-performing detector is suitable for the planned role of the Delta E-detector in the future cell irradiation experiments. (C) 2013 Elsevier B.V. All rights reserved.
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| 6. |
- Borysiuk, Maciek, et al.
(författare)
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Preliminary results of oxygen isotope ratio measurement with a particle-gamma coincidence method
- 2015
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms. - : Elsevier BV. - 0168-583X. ; 348, s. 269-272
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Tidskriftsartikel (refereegranskat)abstract
- The possibility to study variations in the oxygen isotopic ratio with photon tagged nuclear reaction analysis (pNRA) is evaluated in the current work. The experiment described in the article was performed at Lund Ion Beam Analysis Facility (LIBAF) with a 2 MeV deuteron beam. Isotopic fractionation of light elements such as carbon, oxygen and nitrogen is the basis of many analytical tools in hydrology, geology, paleobiology and paleogeology. IBA methods provide one possible tool for measurement of isotopic content. During this experimental run we focused on measurement of the oxygen isotopic ratio. The measurement of stable isotopes of oxygen has a number of applications; the particular one driving the current investigation belongs to the field of astrogeology and specifically evaluation of fossil extraterrestrial material. There are three stable isotopes of oxygen; O-16, O-17 and O-18. We procured samples highly enriched with all three isotopes. Isotopes O-16 and O-18 were easily detected in the enriched samples, but no significant signal from O-17 was detected in the same samples. The measured yield was too low to detect O-18 in a sample with natural abundances of oxygen isotopes, at least in the current experimental setup, but the spectral line from the reaction with O-16 was clearly visible. (C) 2015 Elsevier B.V. All rights reserved.
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| 7. |
- Bulow, K, et al.
(författare)
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The penetration depth and lateral distribution of pigment related to the pigment grain size and the calendering of paper
- 2002
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms. - 0168-583X. ; 189, s. 308-314
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Tidskriftsartikel (refereegranskat)abstract
- The interaction of ink and newspaper has been investigated and the specific question of penetration of ink into the paper has been addressed with a nuclear microprobe using particle induced X-ray emission, The penetration depth of the newsprint is a critical factor in terms of increasing the quality of newsprint and minimising the amount of ink used. The objective of the experiment was to relate the penetration depth of pigment with the calendering of the paper, The dependence of the penetration depth on the pigment grain size was also Studied, To Study the penetration depth of pigment in paper, cyan ink with Cu as a tracer of the coloured pigment was used, For the study of the penetration depth dependence of pigment size. specially grounded Japanese ink with well-defined pigment grain size was used. This was compared to Swedish ink with pigment grains with normal size-distribution, The results show that the calendering of the paper considerably affects the penetration depth of ink. (C) 2002 Elsevier Science B.V. All rights reserved.
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| 10. |
- Goderis, Steven, et al.
(författare)
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Globally distributed iridium layer preserved within the Chicxulub impact structure
- 2021
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Ingår i: Science Advances. - : American Association for the Advancement of Science (AAAS). - 2375-2548. ; 7:9
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Tidskriftsartikel (refereegranskat)abstract
- The Cretaceous-Paleogene (K-Pg) mass extinction is marked globally by elevated concentrations of iridium, emplaced by a hypervelocity impact event 66 million years ago. Here, we report new data from four independent laboratories that reveal a positive iridium anomaly within the peak-ring sequence of the Chicxulub impact structure, in drill core recovered by IODP-ICDP Expedition 364. The highest concentration of ultrafine meteoritic matter occurs in the post-impact sediments that cover the crater peak ring, just below the lowermost Danian pelagic limestone. Within years to decades after the impact event, this part of the Chicxulub impact basin returned to a relatively low-energy depositional environment, recording in unprecedented detail the recovery of life during the succeeding millennia. The iridium layer provides a key temporal horizon precisely linking Chicxulub to K-Pg boundary sections worldwide.
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