Study of the spatial resolution of low-material GEM tracking detectors

The spatial resolution of GEM based tracking detectors has been simulated and measured. The simulation includes the GEANT4 based transport of high energy electrons with careful accounting for atomic relaxation processes including emission of fluorescent photons and Auger electrons and custom post-processing, including accounting for diffusion, gas amplification fluctuations, the distribution of signals on readout electrodes, electronics noise and a particular algorithm of the final coordinate calculation (center of gravity). The simulation demonstrates that a minimum of the spatial resolution of about 10 μm can be achieved with strip pitches from 250 μm to 300 μm. For larger pitches the resolution is quickly degrading reaching 80-100 μm at a pitch of 500 μm. The spatial resolution of low-material triple-GEM detectors for the DEUTRON facility at the VEPP-3 storage ring is measured at the extracted beam facility of the VEPP-4M collider. The amount of material in these detectors is reduced by etching the copper of the GEMs electrodes and using a readout structure on a thin kapton foil rather than on a glass fibre plate. The exact amount of material in one DEUTRON detector is measured by studying multiple scattering of 100 MeV electrons in it. The result of these measurements is X/X0 = 2.4×10−3 corresponding to a thickness of the copper layers of the GEM foils of 3 μm. The spatial resolution of one DEUTRON detector is measured with 500 MeV electrons and the measured value is equal to 35 ± 1 μm for orthogonal tracks.

Mechanical and thermal reliability of conductive circuits inkjet printed on flexible substrates

Purpose This paper aims to present the results of investigations of inkjet-printed electronic circuits fabricated on a flexible substrate (KAPTON foil) using silver nanoparticles ink. Design/methodology/approach Fully inkjet-printed conductive circuit tracks were printed on a flexible, transparent KAPTON foil, using a commercial 40LT-15 C nanosilver ink as well as a PixDro LP50 inkjet printer with KonicaMinnolta 512 printhead. After cure, electrical properties by resistance measurements and printing quality by optical and SEM microscopic observation of conductive tracks were examined. Afterwards, the tested samples were annealed for 1, 2 and 3 h at 150°C or subjected to cycling bending. Findings It was found that silver nanoparticles ink could be used for the preparation of electronic circuits using the inkjet printing technique. The obtained patterns had appropriate mapping and good quality. It was also noticed that thermal annealing caused a decrease in resistivity values of the tested lines irrespective of their width. Approximately 34 per cent decrease was achieved in the values of resistivity of all the tested lines after the first hour of thermal annealing. After the second hour, the values of resistivity decreased by another 50 per cent. There were no visible changes in resistivity values after 1,000 cycles of bending. Originality/value In this paper, the results of thermal annealing and bending tests of inkjet-printed silver nanoparticle conductive tracks on flexible substrate were presented. That is very important information for producing printed circuit boards using ecological, rapid and low-cost inkjet printing techniques, particularly during the production of printed circuit boards on flexible substrates working in different conditions of mechanical and thermal stresses.

Influence of mechanical exposures on electrical properties of thin and thick-film flexible resistors and conductors

Purpose – The purpose of this paper is to determine the influence of mechanical factors (such as longitudinal elongation or cyclic compressive and tensile stresses) on electrical properties of thin- or thick-film resistors or conductors. Design/methodology/approach – All test samples were made on Kapton foil. Copper foil or silver-based polymer thick-film conductive inks were used for fabrication of conductors. Resistive structures were made with the aid of two polymer thick-film resistive inks or OhmegaPly Ni-P resistive foil. Test structures differ not only in materials applied for resistors or conductors but also in geometrical shape of functional tracks (meanders consisted of many horse-shoes, semicircles, squares or triangles). Findings – Presented results showed significant role of material on range of reversible resistance changes. But shape of test samples also affects relation between relative resistance changes and relative elongation. Originality/value – In general, changes induced by cyclic compressive and stretching stresses were smaller than those caused by substrate elongation.

CHARACTERIZATION OF A FEW GEM STONES BY X-RAY EMISSION TECHNIQUES (EDXRF AND EXTERNAL PIXE)

X-ray Emission Techniques (EDXRF) and External Proton Induced X-ray Emission Technique (PIXE) have been used to characterize 13 gem stones obtained from Gem Testing Laboratory, Jaipur, India. Radioisotope sources 109 Cd and 241 Am were used to excite the gem stones to generate K and L X-rays in the low and high Z region of the periodic table to investigate trace element inclusions besides the main matrix. A proton beam of 4 MeV energy and current of 8 nA intensity were extracted from the FOTIA (Folded Tandem Ion Accelerator) at VandeGaaff Accelerator, Trombay, Mumbai in air through a Kapton foil of 8 micrometer thick mounted on a Teflon cone. Gem stones such as Labradorite Feldspar, Moonstone Feldspar, Almandine Garnet, Tsavorite Garnet, Apatite, Natural Spinel, Natural Zircon, Spessartine Garnet, Natural Ruby (Lead filled), Natural Ruby were characterized for their elemental profile to see the differences in composition besides the main matrix differences. Elements such as Ca , Ti , V , Cr , Mn , Fe , Cu , Zn , Sr , Y and Zr were detected.

PHYSICAL QUANTITATIVE ANALYSIS IN IN-AIR PIXE

A physical method of quantitative analysis for in-air PIXE has been established. Among the three parameters required for performing physical analysis, X-ray production cross sections were recalculated by using the effective energy of the proton beam after losing its energy through a Kapton foil and in air. Detection efficiencies of the Si ( Li ) detector have been determined according to our method established for in vacuum system, where effects of absorption of X-rays in air are incorporated into the detection efficiencies. As a result, it is confirmed that the present method gives us accurate results in the analyses of standard samples as well as actual samples such as soil and ash. It becomes possible to perform quantitative analysis of various samples by optimizing the measuring conditions depending on the samples.

Bimorph-type Magnetostrictive Actuator/Sensor Thin Films

ABSTRACTGiant magnetostrictive Fe-Pd and Fe-Ga thin films are expected as actuator/ sensor materials with high respective velocity and huge stress created by the magnetostriction. In order to develop magnetostrictive material induced by low magnetic field, we investigated bimorph-type magnetostrictive (positive magnetostriction / substrate / negative magnetostriction) thin films, that is, Fe-Pd(1, 3µm) or Fe-Ga(1, 3µm)/substlate /Ni(1, 3µm) by magnetron sputtering system. The substrate is Al(50µm) or kapton foil (125µm). Displacement of a upper part of these films was measured using an optical lever method. The displacement of the Fe70-Pd30(3µm )/ Al(50µm)/Ni(3µm)film ( length is 20 mm) was 280 μm under low DC magnetic field of 500 Oe and exhibits little hysteresis. These magnetostrictive properties are maintained under low alternating magnetic field. Moreover, the displacement of the film at the resonance frequency exhibits a peak and reached to 1.4 mm. The bimorph-type magnetostrictive thin film is useful for application in micro device as micro-pomp.

NON-VACUUM PIXE FOR MULTI-ELEMENTAL ANALYSIS OF HEAVY METALS IN STREAM WATER

An improvement has been made on a liquid target preparation for an external proton beam PIXE which is regarded as an excellent technique for multi-elemental analysis of a liquid specimen. A 2.5 MeV proton beam taken out to the atmosphere through an exit Kapton foil bombards an acidic solution target. Such bombardment enables the comparison of X-ray yields of a liquid sample with those of standard solutions so that one can determine the elemental concentration in a liquid sample more precisely and easily. The dose limit of a 7.5 µm Kapton foil was found to be 0.8~1.0 mC for a 2 MeV proton beam of 10 ~ 20 nA in intensity. An example is given for the analysis of heavy metals in stream water.