Gem detectors for X-ray astronomy

Andersson, H.; Andersson, Tom; Heino, J.; Huovelin, J.; Kurvinen, K.; Lauhakangas, R.; Nenonen, S.; Ojala, J.; Orava, R.; Schultz, J.; Sipilä, Heikki; Vilhu, O.

doi:10.1016/j.nima.2003.08.022

Cited by 4 publications

(2 citation statements)

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“…Outgassing studies on polyimides [9] suggest that this point is reached after ∼ 10 hours, at a temperature of 150 • C. This procedure need not be a great complication; contrary to the spherical forming this can be done with many foils at the same time. In addition, GEMs treated in this way have such benign outgassing behavior that they can be used in sealed detectors, where the gas is not flowing [10]. This opens the way to use more efficient gases such as xenon (see figure 1), which would otherwise be prohibitively expensive.…”

Section: Jinst 4 P12006mentioning

confidence: 99%

Making spherical GEMs

et al. 2009

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We developed a method to make GEM foils with a spherical geometry. Tests of this procedure and with the resulting spherical GEMs are presented. Together with a spherical drift electrode, a spherical conversion gap for x-rays can be formed. This would eliminate the parallax error in an x-ray diffraction setup, which limits the spatial resolution at wide diffraction angles. The method is inexpensive and flexible towards possible changes in the design. We show advanced plans to make a prototype of an entirely spherical triple-GEM detector, including a spherical readout structure. This detector will have a superior position resolution, also at wide diffraction angles, and a high rate capability. A completely spherical gaseous detector has never been made before.

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Section: Jinst 4 P12006mentioning

confidence: 99%

Making spherical GEMs

et al. 2009

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“…Una GEM-Foil (del inglés Gas Electron Multiplier Foil) es una placa microperforada que actúa como elemento de amplificación de cargas eléctricas para uso en detectores de partículas por medio de la ionización de gases [1], la cual está permitiendo la exploración de nuevas aplicaciones en diferentes campos como la física de altas energías [2,3], la física médica [4] y la astronomía [5], entre otras. En la figura 1 se muestra una vista en sección transversal y una vista plana de una GEM-Foil.…”

Section: Introductionunclassified

Técnicas de umbralización para el procesamiento digital de imágenes de GEM-Foils

et al. 2016

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Resumen-Una GEM-Foil (Gas Electron Multiplier -Foil) es un componente básico de nuevos detectores de radiación usados principalmente en experimentos de física de altas energías y física nuclear. El desempeño óptimo de tales detectores depende críticamente de la calidad de fabricación de dicho componente, ya que cualquier irregularidad en una de los cientos de miles de micro-perforaciones de la placa puede inducir una chispa durante el funcionamiento y dañar el detector. Actualmente, para evaluar la calidad de fabricación de una GEM-Foil se adquieren imágenes de alta resolución mediante sistemas ópticos que las digitalizan para ser luego examinadas por inspección visual. En este trabajo se comparan varias técnicas para realizar la binarización de las imágenes de las GEM-Foils, aplicando técnicas de umbralización global y local, con el propósito de mejorar la rapidez y eficiencia del procesamiento de las imágenes de las GEM-Foils, para realizar posteriormente su control de calidad. A partir de las pruebas realizadas se encontró que, mediante cálculos estadísticos simples, como el promedio del máximo y mínimo de intensidad, aplicando umbralización local adaptativa es posible realizar la segmentación de las imágenes de una manera eficiente sin tener que recurrir a métodos más complejos los cuales pueden implicar tiempos de proceso demasiado grandes. Palabras clave-Detectores gaseosos, GEM, Placas de detectores, Segmentación de la imagen, Umbralización.Abstract-A GEM-Foil (Gas Electron Multiplier -Foil) is a basic component of new radiation detectors used mainly in high energy physics and nuclear physics experiments. Optimum performance of such detectors depends critically on the quality of manufacture of such component, because any irregularity in one of the hundreds of thousands of micro-perforations in the plate can induce a spark during operation and damage the detector. Currently, in order to assess the quality of a GEM-Foil, high resolution images are acquired through optical systems to be digitized and then examined by visual inspection. In this work, various techniques to perform binarization of the images of the GEM-Foils are compared, by applying techniques of global and local thresholding, in order to improve the speed and efficiency of processing the images of the GEM-Foils for its quality control. From tests it was found that by simple statistical calculations as the average of the maximum and minimum intensity, using local adaptive thresholding is possible to carry out the segmentation of images in an efficient manner without having to use more complex methods which may involve too large process time.

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