| 1. |
- Auzelyte, Vaida, et al.
(författare)
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The beam blanking system for microlithography at Lund Nuclear microprobe
- 2004
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms. - : Elsevier BV. - 0168-583X. ; 219-20, s. 485-489
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Tidskriftsartikel (refereegranskat)abstract
- A new beam blanking system was installed at the Lund Nuclear Microprobe and employed in proton beam lithography (PBL) for polymer microstructures fabrication. The blanker consists of two parallel plates connected to a high voltage generator. Measurement of the beam blanking time on a sample was performed by means of the standard PIXE system. The beam is blanked and returns to a sample within 200 ns. The blanking system is designed for the new sub-micrometer beamline under installation in the accelerator laboratory. A number of pilot MeV ion beam lithography experiments were performed to illustrate the possibility to use the blanking system in combination with the existing data acquisition and scanning system. A 2.5 MeV proton beam was used to irradiate 50 mum SU-8 negative resist. The blanker was shown to be a necessary part of the lithography system. It enables blanking between each pixel and hence fabrication of various patterns down to a single pixel. The blanker has significantly simplified beam control and enhanced process time and spatial resolution. Three-dimensional microstructures with 20:1 aspect ratio were fabricated.
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| 2. |
- 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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| 3. |
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| 4. |
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| 5. |
- Gisselson, L Å, et al.
(författare)
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Dinophysis blooms in the deep euphotic zone of the Baltic Sea: do they grow in the dark?
- 2002
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Ingår i: Harmful Algae. - 1878-1470. ; 1:4, s. 401-418
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Tidskriftsartikel (refereegranskat)abstract
- In situ growth rates of the toxin-producing dinoflagellate Dinophysis norvegica collected in the central Baltic Sea were estimated during the summers of 1998 and 1999. Flow cytometric measurements of the DNA cell cycle of D. norvegica yielded specific growth rates (μ) ranging between 0.1 and 0.4 per day, with the highest growth rates in stratified populations situated at 15–20 m depth. Carbon uptake rates, measured using 14C incubations followed by single-cell isolation, at irradiances corresponding to depths of maximum cell abundance were sufficient to sustain growth rates of 0.1–0.2 per day. The reason for D. norvegica accumulation in the thermocline, commonly at 15–20 m depth, is thus enigmatic. Comparison of depth distributions of cells with nutrient profiles suggests that one reason could be to sequester nutrients. Measurements of single-cell nutrient status of D. norvegica, using nuclear microanalysis, revealed severe deficiency of both nitrogen and phosphorus as compared to the Redfield ratio. It is also possible that suitable prey or substrate for mixotrophic feeding is accumulating in the thermocline. The fraction of cells containing digestive vacuoles ranged from 2 to 22% in the studied populations. Infection by the parasitic dinoflagellate Amoebophrya sp. was observed in D. norvegica in all samples analysed. The frequency of infected cells ranged from 1 to 3% of the population as diel averages, ranging from 0.2 to 6% between individual samples. No temporal trends in infection frequency were detected. Estimated loss rates based on observed infection frequencies were 0.5–2% of the D. norvegica population daily, suggesting that these parasites were not a major loss factor for D. norvegica during the periods of study.
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| 6. |
- Kristiansson, Per, et al.
(författare)
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Development of a system for determination of the C-13/C-12 isotopic ratio with high spatial resolution
- 2004
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms. - : Elsevier BV. - 0168-583X. ; 219-20, s. 561-566
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Tidskriftsartikel (refereegranskat)abstract
- Stable carbon isotopes play an important role in the interpretation of biological activity, particularly when the fossil record is studied. In combination with morphological and chemical data, isotopic information can be useful in paleontology and astrobiology. In this paper the development of a microanalytical ion beam system for the measurement of the carbon isotope ratio with high spatial resolution and good statistics is presented. The technique used is elastic scattering of alpha particles with an energy of 2.75 MeV. At this energy the C-13 cross-section is enhanced relative to the Rutherford cross-section and while the C-12 cross-section is reduced. The optimisation of the system is described, including sample preparation and the design of the particle detection system for high efficiency combined with good energy resolution. Finally, some results from the initial test run of the system are shown and discussed. (C) 2004 Elsevier B.V. All rights reserved.
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| 7. |
- Limburg, K E, et al.
(författare)
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New Insights into Fish Ecology via Nuclear Microscopy of Otoliths
- 2003
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Ingår i: AIP Conf. Proc. -- August 26, 2003. - : AIP. ; 680, s. 339-342
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Konferensbidrag (refereegranskat)abstract
- Otoliths, or earstones, are small, biogenic concretions of aragonitic calcium carbonate precipitated on a protein matrix. Otoliths form part of the hearing and balance system in teleost fishes, and grow as the fish grow, providing a continuous biochronology of growth. Various elements are entrained in minor and trace quantities. In particular, strontium is a useful scalar of habitat use when variable environmental gradients exist. By mapping elemental concentrations and ratios with the Lund nuclear microprobe, we have used strontium in many cases as a proxy for salinity, because Sr:Ca values are roughly an order of magnitude higher in marine vs most fresh waters. In addition, zinc shows strong seasonal variations in salmoniform fishes (salmons, charrs, and whitefishes have been tested to date). We present case studies of several species, and discuss exciting future directions in this research that is revolutionizing fisheries ecology. ©2003 American Institute of Physics
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| 8. |
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| 9. |
- Pallon, Jan, et al.
(författare)
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An off-axis STIM procedure for precise mass determination and imaging
- 2004
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms. - : Elsevier BV. - 0168-583X. ; 219-20, s. 988-993
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Tidskriftsartikel (refereegranskat)abstract
- For the precise determination of the local mass density in thin samples analysed at the Lund Nuclear Microprobe, a modified version of off-axis STIM is described. An on-axis/off-axis geometry is used where a thin C-foil, placed behind the sample scatters protons into the particle detector. The advantage of this geometry compared to the off-axis case where particles are directly scattered from the sample into the particle detector is that the energy-loss spectrum acquired is less degraded. A spectral resolution comparable to on-axis STIM is achieved at a beam current high enough to allow for a simultaneous PIXE analysis (50-100 pA). (C) 2004 Elsevier B.V. All rights reserved.
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| 10. |
- Shariff, Asad, et al.
(författare)
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Calibration of a new chamber using GUPIX software package for PIXE analysis
- 2002
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms. - 0168-583X. ; 189:1-4, s. 131-137
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Tidskriftsartikel (refereegranskat)abstract
- A new chamber has been designed and constructed for the second beam line at the Lund Nuclear Microprobe facility, Sweden. The aim with the chamber is to perform standardized analyses with most of the nuclear analytical techniques (proton induced X-ray emission, particle elastic scattering analysis, proton induced gamma emission, nuclear reaction analysis, etc.) with a millimetre size beam. The beam line and chamber constructions are described in this paper. The possibility to run samples in batch. and the special arrangement developed for this is described. A mass calibration of the PIXE set-up has been done with MicroMatter thin film standards and other thick standards. The spectra were acquired with CAMAC based data acquisition system with Kmax interfacing software. The GUPIX software package recently installed in our laboratory has been used to process the PIXE spectra and the results are compared with the certified values. For standardization the instrumental constant H (solid angle and correction factor) is determined relying completely on the GUPIX data base (cross-sections, fluorescence and Coster-Kronig probabilities, stopping powers and attenuation coefficients) for a large set of elements. These H values are saved inside the GUPIX library, to be used in future analysis.
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