1,721,350 research outputs found
Diamond sensors for future high energy experiments
No full textWith the planned upgrade of the LHC to High-Luminosity-LHC [1], the general purpose experiments ATLAS and CMS are planning to upgrade their innermost tracking layers with more radiation tolerant technologies. Chemical Vapor Deposition CVD diamond is one such technology. CVD diamond sensors are an established technology as beam condition monitors in the highest radiation areas of all LHC experiments. The RD42-collaboration at CERN is leading the effort to use CVD diamond as a material for tracking detectors operating in extreme radiation environments. An overview of the latest developments from RD42 is presented including the present status of diamond sensor production, a study of pulse height dependencies on incident particle flux and the development of 3D diamond sensors
Diamond particle detectors systems in high energy physics
No full textWith the first three years of the LHC running complete, ATLAS and CMS are planningto upgrade their innermost tracking layers with more radiation hard technologies. Chemical VaporDeposition (CVD) diamond is one such technology. CVD diamond has been used extensively inbeam condition monitors as the innermost detectors in the highest radiation areas of BaBar, Belle,CDF and all LHC experiments. The lessons learned in constructing the ATLAS Beam ConditionsMonitor (BCM), Diamond Beam Monitor (DBM) and the CMS Pixel Luminosity Telescope (PLT)all of which are based on CVD diamond with the goal of elucidating the issues that should beaddressed for future diamond based detector systems. The first beam test results of prototypediamond devices with 3D detector geometry should further enhance the radiation tolerance of thismaterial
Preface
No full textThe rapid progress of nanotechnologies poses significant challenges in manufacturing and characterization. Scanning Probe Microscopy (SPM) techniques have significantly contributed to such development, allowing characterization of a number of properties at the microscale and nanoscale. Having been invented for the morphological investigation of surfaces, SPM has represented the basis for the development of techniques where the tip is used for probing physical properties and the SPM position control system is used for imaging such properties on the samples surface, simultaneously to their topography. The combination of scanning probe microscopy, and in particular of Atomic Force Microscopy (AFM) with ultrasound techniques, led to the development of acoustic AFM (A-AFM) and acoustic SPM (A-SPM) opening up to a number of measuring techniques which allow surface mechanical properties imaging. In A-AFM, piezoelectric transducers are used to set the sample surface or the AFM cantilever into vibration at ultrasonic frequencies that are well above the cutoff frequency of the electronics, so that the oscillations are not compensated by the feedback. As a consequence such oscillation does not influence the standard topographical reconstruction, and on the other hand, the ac component of the deflection signal is not suppressed and thus can be subsequently analyzed. The particular way in which ultrasonics and SPM are combined is different for each specific technique and allows collection of different information. Readers working in different fields of nanotechnology, material science, and biology will find in this book a comprehensive overview of such A-SPM techniques, presented by evidencing similarities and peculiarities. We proudly say that the most widely recognized scientists and researchers have contributed to the 17 chapters of the present volume, discussing acoustic SPM techniques both from the theoretical and from the practical points of view. The volume is divided into three parts
Diamond Pixel Detectors and 3D Diamond Devices
No full textResults from detectors of poly-crystalline chemical vapour deposited (pCVD) diamond are presented. These include the first analysis of data of the ATLAS Diamond Beam Monitor (DBM). The DBM module consists of pCVD diamond sensors instrumented with pixellated FE-I4 front-end electronics. Six diamond telescopes, each with three modules, are placed symmetrically around the ATLAS interaction point. The DBM tracking capabilities allow it to discriminate between particles coming from the interaction point and background particles passing through the ATLAS detector. Also, analysis of test beam data of pCVD DBM modules are presented. A new low threshold tuning algorithm based on noise occupancy was developed which increases the DBM module signal to noise ratio significantly. Finally first results from prototypes of a novel detector using pCVD diamond and resistive electrodes in the bulk, forming a 3D diamond device, are discussed. 3D devices based on pCVD diamond were successfully tested with test beams at CERN. The measured charge is compared to that of a strip detector mounted on the same pCVD diamond showing that the 3D device collects significantly more charge than the planar device
Modeling radiation damage in TCAD
No full textThe aim of this work is to develop a TCAD radiation damage model at a device level, enablinga predictive insight on the electrical behaviour of detectors and aiming at their ultimate perfor-mance optimization for the operation at HL-LHC expected fluences (e.g. greater than 2.0×10161 MeV equivalent neutrons/cm2). Our approach aims at keeping the number of fitting parame-ters as low as possible, at the same time accounting for new experimental evidences of relevanteffects at these very high fluences (e.g. charge multiplication and avalanche effects). A physi-cally grounded approach is being pursued, aiming at devising a not over-specific modelling whilekeeping predictive capabilities on the device behavior fabricated by different vendors (e.g. withdifferent technology flavors) and in different operating conditions, e.g. at different fluences, tem-peratures and biasing voltages. The model development follows a test campaign with a twofoldgoal: from one hand, the relevant technology parameters such as oxide charge and interface trapstates as a function of the irradiation dose have been measured. On the other hand, DC and ACmeasurements on gate-controlled diodes and MOS capacitors can be used as reference for TCADsimulation models validation purpose. The complete bulk and surface radiation damage modelcan be exploited for the analysis of the active behavior of different classes of new generationdetectors to be used in the future HEP experiments
Brain natriuretic peptide modulates calcium homeostasis and epidermal growth factor receptor gene signalling in asthmatic airways smooth muscle cells
No full textThe airway epithelium acts as a barrier and provides a critical interface between the body and the external environment. Brain natriuretic peptide (BNP) plays an important role in several bronchial functions, including relaxation. BNP relaxes airways by binding and activating natriuretic peptide receptor-A expressed from the airway epithelium. Although relaxation effect has been extensively investigated, less is known about BNP-regulated intracellular biomolecular pathways leading to bronchial relaxation. To this aim, we investigated BNP effects on gene signalling of airway smooth muscle cells (ASM) obtained from donors with asthma by using a RT(2) profiler™ PCR array. When compared with control, treatment for 2 h with supernatant from BNP-treated (1 μM) bronchial epithelial cells (BEAS-2B) induced in asthmatic ASM cells a rapid reduction of transcription of EGFR and genes involving in actin and calcium homeostasis, as those of Protein kinase C (PKC) and RhoA-ROCK gene pathways. Immunofluorescence and western blotting did not shown any difference comparing control and ASM cells treated with conditioned medium from BNP-treated BEAS-2B. This study provides evidence that the effect of BNP on relaxing bronchial in ASM cells is mediated from epithelium and associates to rapid changes of EGFR and calcium homeostasis-associated gene levels
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