[en] The transmission of 1 MeV proton microbeam through a single, cylindrically shaped, micrometre-sized polytetrafluoroethylene capillary was studied. The capillary axis was tilted with respect to the axis of the incident ion beam. The tilting, the aspect ratio of the capillary and the small beam divergence disabled the geometrical transmission of the beam through the target. The time dependence of the intensity, the charge-state and the deflection of the transmitted beam were investigated. We found that pure guided transmission of a MeV/amu energy ion beam is possible through an insulator capillary

[en] The transmission of 1 MeV proton microbeam passing between two parallel flat plates was investigated. Three different materials were used in our experiments. As insulators we used Polytetrafluoroethylene and borosilicate glass plates and glass with gold layer on the surface as conductor. The surface of the plates was parallel to the beam axis and one of the plates was moved towards the beam. The energy distribution and the deflection of the transmitted beam were measured as the function of the sample distance relative to the beam. We found systematic differences between the behaviour of the metallic and insulator samples. The proton microbeam suffered significant deflection towards the sample surface due to the image acceleration when using conductor material. In case of the glass and Polytetrafluoroethylene plates the beam was deflected into the opposite direction, and the incident protons did not suffer significant energy loss, which is the consequence of the guiding effect

[en] Zinc deficiency is known to cause night blindness, which can be reverted by the administration of zinc. The exact function of zinc is not understood but it is likely that zinc plays a unique role in the phototransduction process and/or photoreceptor/retinal pigment interaction. The localisation of free (histochemically reactive) zinc within the photoreceptors changes with light stimulation [Exp. Eye Res. (1999) 459]. In the dark-adapted retina chelatable zinc can be visualised primarily in the perikarya, whereas after photostimulation free zinc is mainly associated with the inner segments. This variation might be due to (1) a translocation of zinc from the perikarya to the inner segments, (2) a change in the state of zinc (from a free to a bound form, histochemically and non-histochemically reactive, respectively), or (3) zinc influx and/or efflux across the plasma membrane. MicroPIXE was used to analyse the total (free and bound) zinc distribution in each retinal layer and a difference was found between light- and dark-adapted retinas (preliminary data). Following light stimulation the most pronounced difference in the zinc concentration was found in the inner segments of the photoreceptors and the layer containing the photoreceptors perikarya (outer nuclear layer)

[en] ATOMKI has been using a scanning ion microsonde utilizing the 5MV Van de Graaff accelerator's beam. The beam is focused to a 1 μm spot, to investigate samples with that resolution. Since 2002 the ion beam micromachining has been installed to achieve a 3D direct writing lithographic process. The paper summarizes the properties of different direct ion writing methods and their applications. The Proton Beam Machining method is expected to be used in lithographic process of nanoelectronic technology to keep on with the predictions of the Moore Law. (T-R.A.)

[en] The use of prehistoric stone tools can be classified according to the usewear traces on the tool working edge. The polish resulting from the use of the tool contains minute amounts of the original worked material. Using the micro PIXE mapping technique, a comparative study of a set of experimental tools and a set of mesolithic end-scrapers was performed. For both sets of tools, increased concentrations of elements associated with the worked material were found in small localized regions. The composition of these regions was probed by point measurements and two main groups of P, Ca and S, K compounds were identified. The X-ray attenuation in the polish layer suggests that the deposited elements diffuse into the bulk flint

[en] Short communication

[en] Complete text of publication follows. The scanning ion microprobe focuses the ion beam by three quadrupole lenses to the typical spot size of 1 μm. It was already known that the divergence of the focussed beam is small, but the exact value was not necessary for previous applications. For some recent and other planned experiments we needed quantitative values of the beam divergence. Therefore, we have decided to determine the beam divergence at the image plane. First we have observed the changes of the beam size on a fluorescent screen (mounted on the XYZ manipulator of the microprobe), using a camera with a microscope, when the screen moved along the z axis, which is parallel to the beam. Knowing the change in beam diameter and the distance from the focal point we can give the divergence by simple angle calculation. This is illustrated on Figure 1. The object slit size and the image on the target spot (in focus) can be assumed to be negligible, the collimator slit size and the quadrupole triplet focussing properties determine the divergence. The beam scanning was turned off. We have performed the measurements in cases of the two most commonly used collimator slit sizes (50 μm and 400 μm, i.e. the object plane divergence values of 0.0005 deg and 0.004 deg, respectively). The magnetic quadrupole lens produces different demagnifications and divergences in the x (horizontal) and y (vertical) directions, so we have measured in both planes. The evaluation has been carried out using a simple image-editing software. We have calculated the pixel size of the beam, and we also recorded a micrometer scale for calibration. The measurements showed that the divergence was so small that the maximum z offset of the target (about 9 mm) was not enough to determine the illuminated area accurately. In the next series of experiments the fluorescent screen was placed at a fixed distance of 103.4 mm from the beam focal plane (i.e. the back flange of the target chamber), thus the beam was sufficiently expanded to perform a more accurate determination of the size of the rectangular illuminated area. The images clearly showed the y divergences being smaller than in the x plane, and the smaller collimator slit sizes resulting in smaller divergences. The results are summarized in Table 1. We have also performed theoretical model calculations by the PRAM software, and found a very good agreement.

[en] In this paper we investigate further the potential of proton beam micromachining (PBM) on three different materials: the polymers PMMA and CR-39, and the photowritable glass Foturan. A focused beam of 2 MeV protons delivered by the nuclear microprobe of ATOMKI was used to pattern these materials. The parameters of PBM and the obtained structures are presented

[en] Complete text of publication follows. Proton Beam Micromachining, also known as P-beam Writing, is a direct write 3- dimensional lithographic technique. Conventional resist types are PMMA (polymethylmethacrylate), and SU-8 (of MicroChem Corp.); they are positive and negative resists, respectively. In this work we used SU-8, the most common negative resist material. SU-8 was spun on a flat surface, typically Silicon or glass. A direct write proton beam was scanned over an arbitary structure (the Atomki logo can be replaced by any other structure), which produces chain scissioning in the polymer. Post exposure bake (PEB) is usually needed in case of conventional optical lithography, but using protons this bake is done in situ as the ions heat up the sample in vacuum. Subsequently chemical etching takes place, the solvent is available at MicroChem Corp. The schematic diagram of the above described micromachining process is shown on Fig. 1. The irradiation requires a scanning proton microbeam system equipped with suitable beam scanning and blanking facilities. This is available in the Institute, our setup has been upgraded from doublet to triplet focusing system (Oxford Microbeams Ltd.). For scanning we use a DIO card (PCI-6731 of National Instruments), and the IonScan software [1]. Sample preparation was carried out at our 'semi clean' room. This is also where chemical development of the samples and the optical microscopy have been done too. A Zeiss Axio Imager microscope is available (equipped with 5 objective lenses, 4 different contrast methods, transmitted or reflected light illumination). Fig. 2. shows a typical example of the Atomki logo. This is a bright field image, a number of different nice and colourful images can be produced with the other contrast techniques (for more images see the Institute website: http://www.atomki.hu/ ). (author)

[en] A new in-vacuum micro-PIXE experimental set-up has been realised at an Oxford-type scanning nuclear microprobe facility. It is based on the simultaneous use of an ultra thin windowed detector and a conventional Be-windowed one for the measurement of the characteristic X-rays of light and heavier elements in the E∼0.2-6 keV and E>4 keV energy ranges, respectively. Complete analytical characterisation of samples from carbon to uranium is possible in a single irradiation process. Performance and technical developments are described in detail