| 1. |
- Aguer, P, et al.
(author)
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Skin morphology and layer identification using different STIM geometries
- 2005
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In: Nuclear Instruments & Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms. - : Elsevier BV. - 0168-583X. ; 231:1-4, s. 292-299
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Journal article (peer-reviewed)abstract
- The use of on-axis geometry in scanning transmission ion microscopy (STIM) has been widely used for thin biological sample structure identification. In this configuration, the lateral resolution is optimised so that micron or submicron beam spots are easily achieved even for classic microbeam lines. Off-axis STIM was more particularly employed for rapid imaging, and also (when associated to a scattering set-up) for normalising elemental contents obtained by other ion beam analysis techniques in organic thin samples. Due to the very small beam current required, on-axis STIM is a stand-alone technique. Off-axis STIM can be advantageous as it enables the simultaneous utilisation of PIXE and RBS techniques. In this paper, the STIM images obtained with an on-axis geometry, a standard off-axis geometry and a recently developed on-off geometry are presented and discussed. Data from skin samples are used for comparison purposes aiming at studying skin permeability to sunscreens. Skin is a stratified tissue and the precise identification of skin layers is needed to ascertain the penetration depth of the physical filter from the formulation. In addition to the intrinsic difference in image quality due to the beam resolution, the influence of the detector type, implanted silicon detector versus Si pin diode, is discussed on the basis of their energy resolution.. their resistance to beam damage as well as the effect
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| 2. |
- Arteaga, Natalia, et al.
(author)
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A SU-8 dish for cell irradiation
- 2007
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In: Nuclear Instruments & Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms. - : Elsevier BV. - 0168-583X. ; 263:2, s. 523-528
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Journal article (peer-reviewed)abstract
- The objective of the CELLION project is radiation research at low doses. The main cell responses to low dose irradiation are bystander effects, genomic instability and adaptive responses. In order to study these effects it is convenient to make the cells addressable in space and time through locking the cell position. A new alternative dish has been developed for irradiation procedures at the Lund Nuclear Probe. The versatile dish can be used both to cultivate and to hold the cells during the irradiation procedure. The irradiation dish is made of an epoxy-based photopolymer named SU-8 chosen by its flexibility, non-toxicity and biological compatibility to cell attachment. It has been fabricated using a UV lithographic technique. The irradiation dish forms a 2 × 2 mm2 grid which contains 400 squares. Each square has 80 μm side and is separated from neighbouring ones by 20 μm wide walls. The location of each square is marked by a row letter and column number patterned outside the grid. The Cell Irradiation Facility at the Lund Nuclear Probe utilizes protons to irradiate living cells. A post-cell detection set up is used to control the applied dose, detecting the number of protons after passing through the targeted cell. The transmission requirement is fulfilled by our new irradiation dish. So far, the dish has been used to perform non-targeted irradiation of Hepatoma cells. The cells attach and grow easily on the SU-8 surface. In addition, the irradiation procedure can be performed routinely and faster since the cells are incubated and irradiated in the same surface.
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| 3. |
- Arteaga, Natalia, et al.
(author)
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Applications of SU-8 in the development of a Single Ion Hit Facility
- 2009
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In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms. - : Elsevier BV. - 0168-583X. ; 267:12-13, s. 2117-2121
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Conference paper (peer-reviewed)abstract
- The Lund Nuclear Microprobe (LNM) has been adapted to be used as a Single Ion Hit Facility (SIHF) for proton cell irradiation experiments at low dose. In order to test the capabilities of the system, Ni dot arrays and artificial cells have been fabricated with the photopolymer SU-8 and common lithographic techniques. The primary purpose of the Ni dot arrays was to determine the targeting accuracy of the beam in vacuum and in air. Additionally, this sample was employed to evaluate the system performance during cell target irradiation experiments. The Ni dot arrays were also used for beam characterization. The artificial cells were originally fabricated to test the software for cell recognition and localization, developed and implemented at the LNM. However, this sample became very functional to make small adjustments at the irradiation chamber for cell irradiation experiments. A description of the samples, fabrication procedure and applications are presented in this paper. (C) 2009 Elsevier B.V. All rights reserved.
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| 4. |
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| 5. |
- Arteaga, Natalia, et al.
(author)
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The new cell irradiation facility at the Lund nuclear probe
- 2007
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In: 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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Journal article (peer-reviewed)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.
(author)
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Exposure parameters for MeV proton beam writing on SU-8
- 2006
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In: Microelectronic Engineering. - : Elsevier BV. - 1873-5568 .- 0167-9317. ; 83:10, s. 2015-2020
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Journal article (peer-reviewed)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.
(author)
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Fabrication of phosphor micro-grids using proton beam lithography
- 2006
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In: 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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Journal article (peer-reviewed)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.
(author)
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On-line measurement of proton beam current in pA range
- 2006
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In: Nuclear Instruments & Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms. - : Elsevier BV. - 0168-583X. ; 249, s. 760-763
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Journal article (peer-reviewed)abstract
- A MeV proton beam with a current in the range of fA-nA is usually measured using a secondary beam signal that is dependent on a sample or requires noise-free accurate charge integration in a Faraday cup. We propose a simple on-line beam current measurement setup that can be used to directly measure beam current during ion beam analysis. A fast beam blanker is used to modulate the beam position after the last set of collimator slits in and out of a mini Faraday cup connected to fA-sensitive electrometer. Less than 100 fA current can be measured during an undisturbed irradiation with kHz sampling frequency. The fast, simple and easily controlled current measurement set-up is going to be routinely used for ion beam analysis and modification at the new Lund sub-micron beam line. (c) 2006 Elsevier B.V. All rights reserved.
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| 9. |
- Elfman, Mikael, et al.
(author)
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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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In: 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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Journal article (peer-reviewed)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.
(author)
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First results from the Lund NMP particle detector system
- 2009
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In: 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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Conference paper (peer-reviewed)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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