A demonstrator for the Micro-Vertex-Detector of the CBM experiment

CMOS sensors are the most promising candidates for the Micro-Vertex-Detector (MVD) of the CBM experiment at GSI, as they provide an unprecedented compromise between spatial resolution, low material budget, adequate radiation tolerance and readout speed. To study the integration of these sensors into a detector module, a so-called MVD-demonstrator has been developed. The demonstrator and its in-beam performance will be presented and discussed in this work

Fragility analysis of concrete elevated water tanks under seismic loads

The design of concrete elevated water tanks involves several kinds of uncertainties. Traditionally, the design of these structures is based on a deterministic analysis. Partial safety factors prescribed in design codes are applied to take into account these uncertainties and to ensure sufficiently safe design. However, this approach does not allow rational evaluation of the risk related to the structural failure and consequently its reliability. In fact, the partial safety factors can lead to over-designed structures; or to under designed structural components leading to a lack of structural robustness. In this study, a probabilistic approach based on Monte Carlo simulations is used to analyze the reliability of elevated water tanks submitted to hazard seismic loading. This reliability approach, takes into account mainly two parameters. Firstly, the hydraulic charge in the tank container which is a function of time, and secondly, the hazard seismic loading through the Peak Ground Acceleration is considered as a random variable. Fragility curves depending on seismic zones and soil types are obtained by using the probabilistic approach, where they demonstrate the dominant failure modes that can cause the structural failure with respect to different seismic levels, soil types and water height level in the tank container

Scanning Acoustic Microscopy of Annealing Effects for Aluminium Thin Film Deposited on Silicon Substrate

Scanning acoustic microscope (SAM) has proved to be a powerful new technique for investigation and characterization of mechanical properties of materials, especially, the opaque ones. Non-destructive measurements can be carried out using SAM in the vicinity of materials’ surfaces or relatively deeper away from them. The present work is focussed on the effects of annealing on mechanical properties of samples composed of an Al layer (10 μμm) on Si substrate. Combining the results obtained from the so-called acoustic signature and acoustic images of the Al/Si interface with those from the lateral and longitudinal waves (Rayleigh speeds), it is possible to deduce that the best homogeneous adhesion is obtained after annealing at 500°C.Сканирующий акустический микроскоп (САМ) является мощным современным инструментом для исследования и определения механических свойств материалов, особенно непрозрачных. САМ позволяет проводить неразрушающие исследования материалов как вблизи их поверхности, так и на некотором расстоянии от неё вглубь образца. Работа посвящена изучению влияния отжига на механические свойства образцов, состоящих из слоя Al (10 мкм) на подложке из Si. Объединяя результаты, полученные на основании измерений так называемой акустической сигнатуры и акустических изображений интерфейса Al/Si с использованием поперечных и продольных волн (скоростей Рэлея), можно сделать вывод, что наилучшая гомогенная адгезия реализуется после отжига при 500°С.Сканівний акустичний мікроскоп (САМ) є потужнім новим інструментом для дослідження та визначення механічних властивостей матеріялів, особливо непрозорих. САМ уможливлює проводити неруйнівні дослідження матеріялів як поблизу поверхні, так і на деякій віддалі від неї углиб зразка. Робота стосується вивчення впливу відпалу на механічні властивості зразків, що складаються з шару Al (10 мкм) на підложжі з Si. Поєднуючи результати, одержані з так званої акустичної сиґнатури й акустичних зображень інтерфейсу Al/Si з використанням поперечних і поздовжніх хвиль (Релейових швидкостей), можна зробити висновок, що найліпша гомогенна адгезія реалізується після відпалу за 500°С

Radiation Tolerance of CMOS Monolithic Active Pixel Sensors with Self-Biased Pixels

CMOS Monolithic Active Pixel Sensors (MAPS) are proposed as a technology for various vertex detectors in nuclear and particle physics. We discuss the mechanisms of ionizing radiation damage on MAPS hosting the the dead time free, so-called self bias pixel. Moreover, we discuss radiation hardened sensor designs which allow operating detectors after exposing them to irradiation doses above 1 Mra

Status of the Micro Vertex Detector of the Compressed Baryonic Matter Experiment

The CBM experiment will investigate heavy-ion collisions at beam energies from 8 to 45 AGeV at the future accelerator facility FAIR. The goal of the experiment is to study the QCD phase diagram in the vincinity of the QCD critical point. To do so, CBM aims at measuring rare probes among them open charm. In order to identify those rare and short lived particles despite the rich combinatorial background generated in heavy ion collisions, a micro vertex detector (MVD) providing an unprecedented combination of high rate capability and radiation hardness, very light material budget and excellent granularity is required. In this work, we will discuss the concept of this detector and summarize the status of the R&D