Low Gain Avalanche Detectors (LGAD) for particle physics and synchrotron applications

A new avalanche silicon detector concept is introduced with a low gain in the region of ten, known as a Low Gain Avalanche Detector, LGAD. The detector's characteristics are simulated via a full process simulation to obtain the required doping profiles which demonstrate the desired operational characteristics of high breakdown voltage (500 V) and a gain of 10 at 200 V reverse bias for X-ray detection. The first low gain avalanche detectors fabricated by Micron Semiconductor Ltd are presented. The doping profiles of the multiplication junctions were measured with SIMS and reproduced by simulating the full fabrication process which enabled further development of the manufacturing process. The detectors are 300 μm thick p-type silicon with a resistivity of 8.5 kΩcm, which fully depletes at 116 V. The current characteristics are presented and demonstrate breakdown voltages in excess of 500 V and a current density of 40 to 100 nAcm−2 before breakdown measured at 20oC. The gain of the LGAD has been measured with a red laser (660 nm) and shown to be between 9 and 12 for an external bias voltage range from 150 V to 300 V

O DISCURSO DA EDUCAÇÃO COMO NEGÓCIO: ANÁLISE DE UM EPISÓDIO DO PROGRAMA MUNDO S/A

This article intends to establish connections between concepts of Critical Discourse Analysis and Discourse Analysis of French tradition, in order to demonstrate the conceptual confluences that culminate in a textual, social and historical analysis of texts produced in the present time. Some linguistic material, provided by dialogical interactions between agents on a paid television program will be analyzed, showing that lexical choices and the way numerical data are presented can indicate power relations consolidated by capitalism within the scope of educational training that is necessary today and in the future, without ceasing to treat, briefly, the characteristics that this genre carries. It was also tried to understand the instaurations of the subject in the discursive formations and their relationship with the other, with the viewer, in this case, showing how the discourse is marked by this otherness, but also, as it ends up (trying to) construct the real shared by the parties involved.Este artículo pretende establecer conexiones entre conceptos del Análisis Crítico del Discurso y del Análisis del Discurso de tradición francesa, para demostrar las confluencias conceptuales, que culminan en un análisis textual, social e histórico de textos producidos en la actualidad. Se presentarán análisis del material lingüístico proporcionado por interacciones dialógicas entre agentes en un programa de televisión cerrada, mostrando que las elecciones léxicas y la forma como se presentan datos numéricos pueden indicar relaciones de poder consolidadas por el capitalismo, dentro del ámbito de la formación educativa que se hace necesaria hoy y en el futuro, sin dejar de tratar, de forma sucinta, de las características que ese género carga. También se intentó entender las instauraciones del sujeto en las formaciones discursivas y su relación con el otro, con el espectador, en este caso, mostrando cómo el discurso está marcado por esa alteridad, pero también, como él acaba por (intentar) construir el real compartido por las partes implicadas.Este artigo pretende estabelecer conexões entre conceitos da Análise Crítica do Discurso e da Análise do Discurso de tradição francesa, de modo a demonstrar as confluências conceituais que culminam em uma análise textual, social e histórica de textos produzidos na atualidade. Serão apresentadas análises do material linguístico fornecido por interações dialógicas entre agentes em um programa da televisão fechada, mostrando que as escolhas lexicais e a forma como são apresentados dados numéricos podem indicar relações de poder consolidadas pelo capitalismo, dentro do âmbito da formação educacional que se faz necessária hoje e no futuro. Também tentou-se entender as instaurações do sujeito nas formações discursivas e sua relação com o outro, com o espectador, neste caso, mostrando como o discurso é marcado por essa alteridade, mas, também, como ele acaba por (tentar) construir o real compartilhado pelas partes envolvidas

Edge pixel response studies of edgeless silicon sensor technology for pixellated imaging detectors

Silicon sensor technologies with reduced dead area at the sensor's perimeter are under development at a number of institutes. Several fabrication methods for sensors which are sensitive close to the physical edge of the device are under investigation utilising techniques such as active-edges, passivated edges and current-terminating rings. Such technologies offer the goal of a seamlessly tiled detection surface with minimum dead space between the individual modules. In order to quantify the performance of different geometries and different bulk and implant types, characterisation of several sensors fabricated using active-edge technology were performed at the B16 beam line of the Diamond Light Source. The sensors were fabricated by VTT and bump-bonded to Timepix ROICs. They were 100 and 200 μ m thick sensors, with the last pixel-to-edge distance of either 50 or 100 μ m. The sensors were fabricated as either n-on-n or n-on-p type devices. Using 15 keV monochromatic X-rays with a beam spot of 2.5 μ m, the performance at the outer edge and corners pixels of the sensors was evaluated at three bias voltages. The results indicate a significant change in the charge collection properties between the edge and 5th (up to 275 μ m) from edge pixel for the 200 μ m thick n-on-n sensor. The edge pixel performance of the 100 μ m thick n-on-p sensors is affected only for the last two pixels (up to 110 μ m) subject to biasing conditions. Imaging characteristics of all sensor types investigated are stable over time and the non-uniformities can be minimised by flat-field corrections. The results from the synchrotron tests combined with lab measurements are presented along with an explanation of the observed effects

Multistrip synthetic single-crystal-diamond photodiode based on a p-type/intrinsic/Schottky metal transverse configuration

A synthetic multistrip single-crystal-diamond detector based on a p -type/intrinsic diamond/Schottky metal transverse configuration, operating at zero-bias voltage, was developed. The device was characterized at the Diamond Light Source synchrotron in Harwell (UK) under monochromatic high-flux X-ray beams from 6 to 20 keV and a micro-focused 10 keV beam with a spot size of ~3 μm . No significant pixel-to-pixel variation of both spectral responsivity and time response, high spatial resolution and good signal uniformity along each strip were found, suggesting the tested device structure as a promising sensor for X-ray and UV radiation imaging

Precision scans of the pixel cell response of double sided 3D pixel detectors to pion and x-ray beams

hree-dimensional (3D) silicon sensors offer potential advantages over standard planar sensors for radiation hardness in future high energy physics experiments and reduced charge-sharing for X-ray applications, but may introduce inefficiencies due to the columnar electrodes. These inefficiencies are probed by studying variations in response across a unit pixel cell in a 55μm pitch double-sided 3D pixel sensor bump bonded to TimePix and Medipix2 readout ASICs. Two complementary characterisation techniques are discussed: the first uses a custom built telescope and a 120GeV pion beam from the Super Proton Synchrotron (SPS) at CERN; the second employs a novel technique to illuminate the sensor with a micro-focused synchrotron X-ray beam at the Diamond Light Source, UK. For a pion beam incident perpendicular to the sensor plane an overall pixel efficiency of 93.0±0.5% is measured. After a 10o rotation of the device the effect of the columnar region becomes negligible and the overall efficiency rises to 99.8±0.5%. The double-sided 3D sensor shows significantly reduced charge sharing to neighbouring pixels compared to the planar device. The charge sharing results obtained from the X-ray beam study of the 3D sensor are shown to agree with a simple simulation in which charge diffusion is neglected. The devices tested are found to be compatible with having a region in which no charge is collected centred on the electrode columns and of radius 7.6±0.6μm. Charge collection above and below the columnar electrodes in the double-sided 3D sensor is observed