| 1. |
- Nilsson, Charlotta, et al.
(författare)
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Characterisation of a pre-cell hit detector to be used in single cell irradiation experiments at the Lund Nuclear Microprobe
- 2008
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms. - Amsterdam : Elsevier BV. - 0168-583X .- 1872-9584. ; 266:21, s. 4808-4815
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes the characterisation of an ultra-thin silicon semicondoctor Delta E detector to be used as a pre-cell ion hit detector in single ion experiments on individual, living cells. The characteristics of interest for this specific application are the hit detection efficiency, which has to be close to 100% to enable bombardment with either a single ion or a counted number of ions, the beam spreading, which should be as small as possible to maintain the targeting accuracy, and the vacuum tightness, since the detector is intended, if possible, to be used simultaneously as vacuum window. The hit detection efficiency was shown to be above 99% when detecting alpha particles or 2 MeV protons, the increase in beam size was about 1 mu m and the vacuum tightness was comparable to that of the Si3N4 wafer which is normally used as vacuum window, thus the Delta E detector fulfils the main criteria to function properly as a single ion hit detector. (C) 2008 Elsevier B.V. All rights reserved.
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| 2. |
- Nilsson, Charlotta, et al.
(författare)
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Evaluation of a pre-cell hit detector for the future single ion hit facility in Lund
- 2006
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms. - : Elsevier BV. - 0168-583X .- 1872-9584. ; 249:1-2, s. 924-927
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Tidskriftsartikel (refereegranskat)abstract
- Currently, a single ion hit facility, for irradiation of single cells with single, light MeV ions is under development at the Lund Nuclear Microprobe. In this paper, a novel approach to the ion detection issue is presented. A silicon detector, a type utilized at other facilities for post-cell ion detection, has been investigated as a possible option for pre-cell hit detection. If proven successful, this detector could possibly also be used simultaneously as vacuum window. The first experiments carried out on the 9 mu m thick silicon detector, with an area of 4 mm(2), have been aimed at investigations of signal-to-noise ratio and efficiency. The results thus far reveal a low noise level and a noise distribution, which is well separated from the signal peak. However, the efficiency remains a problem, since at present it is far from the required 100%.
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| 3. |
- Pallon, Jan, et al.
(författare)
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At the Tip of an MeV Beam: Provoking Cells and Performing Tomographic Imaging
- 2009
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Ingår i: Acta Physica Polonica A. - 0587-4246. ; 115:2, s. 501-506
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Konferensbidrag (refereegranskat)abstract
- Biological applications of ion beams have recently become a new important research field using single ion hit facilities to study individual living cells and their response to the hit of a counted number of ions. One motivation is the search for a better understanding of the fundamental processes taking place in cells and organs as a result of irradiation. Another comes from the increasing interest in using high energy protons and heavy ions as a modality for radiotherapy of deep seated tumours. In the view of treatment efficiency, study of cell culture behaviour under controlled radiation experiments, and in different chemical environments at single ion hit facilities, is a first step towards a better understanding of the processes. Tomographic techniques are applicable to situations where you need information of the inside of an object but do not want to section it into thin slices or cannot do it. Using focused MeV ion beams for tomography restricts the sample size to the order of 10-100 mu m, depending of the initial energy. On the other hand, the ability to focus at a sub-micrometer level makes ion beams well suited for analyses of small sized objects as cells, spores, etc. The scanning transmission ion microscopy mode of tomography gives the mass density and corresponding morphological structure of holes and pores. It can then be used to correct the results from the other mode, particle induced X-ray emission tomography. Here is discussed a porosity analysis of bentonite clay that is planned to form an important buffer zone around canisters filled with spent nuclear reactor fuel waste deposited 500 m underground in Sweden.
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| 4. |
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| 5. |
- Arteaga, Natalia, et al.
(författare)
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The new cell irradiation facility at the Lund nuclear probe
- 2007
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms. - : Elsevier BV. - 0168-583X. ; 260:1, s. 91-96
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Tidskriftsartikel (refereegranskat)abstract
- The CELLION project is directed towards the studies on cellular response to targeted single ions. This paper gives an account of the modifications made at the Lund sub-micron beam line in order to create a Single Ion Hit Facility for biological applications within the CELLION project. The most relevant new feature is the specially developed software used to locate the cells. A program for cell recognition and localization that gives the coordinates of the centre of the cells has been designed. The recognition is made online. A picture taken by a microscope is used as input parameter for the recognition program. Using V79 Chinese hamster cells, the recognition procedure can be done in less than 0.5 s for a picture size of 800 x 600 pixels with approximately 96% efficiency. This paper also reports target accuracy test results and the first non-targeted irradiation procedure performed at the Lund sub-micron beam line. (c) 2007 Elsevier B.V. All rights reserved.
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| 6. |
- Auzelyte, Vaida, et al.
(författare)
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Exposure parameters for MeV proton beam writing on SU-8
- 2006
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Ingår i: Microelectronic Engineering. - : Elsevier BV. - 1873-5568 .- 0167-9317. ; 83:10, s. 2015-2020
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Tidskriftsartikel (refereegranskat)abstract
- Proton beam writing was performed on a lithographic resist to determine the main parameters required to achieve the minimum feature size, maximum pattern lateral density and maximum aspect ratio. A 2.5 MeV proton beam focused to sizes between 1.5 and 2.5 mu m was used to expose SU-8 negative resist. The number of protons per pixel was varied in the exposure of SU-8 with thicknesses between 5 and 95 pm. Patterns consisting of single pixels, single-pixel lines and multi-pixel areas with different densities were fabricated. The smallest structures achieved were posts 1.5 pin in diameter with 4:1 structure-space ratio in 15 pm thick resist and the highest aspect ratio structures of 20:1 in 40 pm resist were produced. It was found that the minimum feature size depended only on the beam size, and +/- 10% post size accuracy could be achieved within 40-70% variation of the number of protons. MeV proton beam allows a direct fabrication of complex shapes without a mask in single-step irradiation and. in addition, no proximity correction is needed. We present examples of MeV proton beam written single and multi-pixel microstructures with easily reproducible high aspect ratios and densities. (c) 2006 Elsevier B.V. All rights reserved.
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| 7. |
- Auzelyte, Vaida, et al.
(författare)
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Fabrication of phosphor micro-grids using proton beam lithography
- 2006
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms. - : Elsevier BV. - 0168-583X. ; 242:1-2, s. 253-256
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Tidskriftsartikel (refereegranskat)abstract
- A new nuclear microscopy technique called ion photon emission microscopy or IPEM was recently invented. IPEM allows analysis involving single ions, such as ion beam induced charge (IBIC) or single event upset (SEU) imaging using a slightly modified optical microscope. The spatial resolution of IPEM is currently limited to more than 10 mu m by the scattering and reflection of ion-induced photons, i.e. light blooming or spreading, in the ionoluminescent phosphor layer. We are developing a '' Microscopic Gridded Phosphor '' (also called Black Matrix) where the phosphor nanocrystals are confined within the gaps of a micrometer scale opaque grid, which limits the amount of detrimental light blooming. MeV-energy proton beam lithography is ideally suited to lithographically form masks for the grid because of high aspect ratio, pattern density and sub-micron resolution of this technique. In brief, the fabrication of the grids was made in the following manner: (1) a MeV proton beam focused to 1.5-2 mu m directly fabricated a matrix of pillars in a 15 mu m thick SU-8 lithographic resist; (2) 7:1 aspect ratio pillars were then formed by developing the proton exposed area; (3) Ni (Au) was electrochemically deposited onto Cu-coated Si from a sulfamate bath (or buffered CN bath); (4) the SU-8 pillars were removed by chemical etching; finally (5) the metal micro-grid was freed from its substrate by etching the underlying Cu layer. Our proposed metal micro-grids promise an order-of-magnitude improvement in the resolution of IPEM.
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| 8. |
- 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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| 9. |
- Elfman, Mikael, et al.
(författare)
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The Lund Nuclear Microprobe sub-micron set-up. Part III: Sample stage, optical imaging and detector configuration in the experimental chamber
- 2005
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms. - : Elsevier BV. - 0168-583X. ; 231:1-4, s. 14-20
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Tidskriftsartikel (refereegranskat)abstract
- A new sub-micron beamline for high-resolution nuclear microprobe applications has been constructed at the Lund nuclear microprobe facility. The design and construction of the main experimental chamber.. sample viewing system and computer controlled precision sample stage movement is presented in this paper. The chamber is especially designed for using a large area annular HPGe detector. The advantages with such a large area detector are discussed and illustrated. In addition the quality of the optical viewing and the precision sample stage is discussed.
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| 10. |
- Golubev, Pavel, et al.
(författare)
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First results from the Lund NMP particle detector system
- 2009
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Ingår i: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms. - : Elsevier BV. - 0168-583X. ; 267:12-13, s. 2065-2068
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Konferensbidrag (refereegranskat)abstract
- The design and first results from a Double Sided Silicon Strip Detector (DSSSD) recently installed at the Lund Nuclear Microprobe facility (NMP) are presented. The detector has 64 sector strips and 32 ring strips, which in combination give more than 2000 detector cells, each with characteristics comparable with a standard surface barrier detector (SBD). The detector has been tested both with radioactive sources and with different ion beams and energies. The most striking features are the high rate virtually pile-up free operation and also the possibility of detailed measurement of angular distributions. (C) 2009 Elsevier B.V. All rights reserved.
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