88 research outputs found
Business Models For Transport eBusiness
In this paper authors are presenting expectations from electronic commerce and its connotations on transport logistics. Based on trends, the relations between the companies in the international transport have to be strengthened using Internet business models. In the paper authors are investigating e-business information models for usage in transportbusiness models, eBusiness, digital economy, transport
AstroPix: Investigating the Potential of Silicon Pixel Sensors in the Future of Gamma-ray Astrophysics
This paper details preliminary photon measurements with the monolithic
silicon detector ATLASPix, a pixel detector built and optimized for the CERN
experiment ATLAS. The goal of this paper is to determine the promise of
pixelated silicon in future space-based gamma-ray experiments. With this goal
in mind, radioactive photon sources were used to determine the energy
resolution and detector response of ATLASPix; these are novel measurements for
ATLASPix, a detector built for a ground-based particle accelerator. As part of
this project a new iteration of monolithic Si pixels, named AstroPix, have been
created based on ATLASPix, and the eventual goal is to further optimize
AstroPix for gamma-ray detection by constructing a prototype Compton
telescope.The energy resolution of both the digital and analog output of
ATLASPix is the focus of this paper, as it is a critical metric for Compton
telescopes. It was found that with the analog output of the detector, the
energyresolution of a single pixel was 7.69 +/- 0.13% at 5.89 keV and 7.27 +/-
1.18% at 30.1 keV, which exceeds the conservative baseline requirements of 10%
resolution at 60 keV and is an encouraging start to an optimistic goal of<2%
resolution at 60 keV. The digital output of the entire detector consistently
yielded energy resolutions that exceeded 100% for different sources. The analog
output of the monolithic silicon pixels indicates that thisis a promising
technology for future gamma-ray missions, while the analysis of the digital
output points to the need for a redesign of future photon-sensitive monolithic
silicon pixel detectors.Comment: 12 pages, proceedings, International Society for Optics and Photonics
(SPIE) Astronomical Telescopes and Instrumentation Digital Forum, Dec. 14-18
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AstroPix: investigating the potential of silicon pixel sensors in the future of gamma-ray astrophysics
This paper details preliminary photon measurements with the monolithic silicon detector ATLASPix, a pixel detector built and optimized for the CERN experiment ATLAS. The goal of this paper is to determine the promise of pixelated silicon in future space-based gamma-ray experiments. With this goal in mind, radioactive photon sources were used to determine the energy resolution and detector response of ATLASPix; these are novel measurements for ATLASPix, a detector built for a ground-based particle accelerator. As part of this project a new iteration of monolithic Si pixels, named AstroPix, have been created based on ATLASPix, and the eventual goal is to further optimize AstroPix for gamma-ray detection by constructing a prototype Compton telescope.The energy resolution of both the digital and analog output of ATLASPix is the focus of this paper, as it is a critical metric for Compton telescopes. It was found that with the analog output of the detector, the energyresolution of a single pixel was 7.69 +/- 0.13% at 5.89 keV and 7.27 +/- 1.18% at 30.1 keV, which exceeds the conservative baseline requirements of 10% resolution at 60 keV and is an encouraging start to an optimistic goal of<2% resolution at 60 keV. The digital output of the entire detector consistently yielded energy resolutions that exceeded 100% for different sources. The analog output of the monolithic silicon pixels indicates that thisis a promising technology for future gamma-ray missions, while the analysis of the digital output points to the need for a redesign of future photon-sensitive monolithic silicon pixel detectors
Novel Front-End Design with High-voltage Transceiver ASICs for Ultrasound Computed Tomography
3D Ultrasound Computed Tomography (USCT) is an imaging method for early breast cancer detection. The third generation 3 USCT device is developed at Karlsruhe Institute of Technology. The USCT III device has a hemispherical transducer distribution and emits and receives nearly spherical waves. This enables reflection and transmission imaging simultaneously and fully in 3D. The main challenges for the front-end design are to integrate a large number of transducers, to allow high voltage coded excitation, and to receive low amplitude signals with high quality. These challenges were solved using a smart sensor frontend design with a custom application specific integrated circuit (ASIC)
Prototype Active Silicon Sensor in 150 nm HR-CMOS Technology for ATLAS Inner Detector Upgrade
The LHC Phase-II upgrade will lead to a significant increase in luminosity,
which in turn will bring new challenges for the operation of inner tracking
detectors. A possible solution is to use active silicon sensors, taking
advantage of commercial CMOS technologies. Currently ATLAS R&D programme is
qualifying a few commercial technologies in terms of suitability for this task.
In this paper a prototype designed in one of them (LFoundry 150 nm process)
will be discussed. The chip architecture will be described, including different
pixel types incorporated into the design, followed by simulation and
measurement results.Comment: 9 pages, 9 figures, TWEPP 2015 Conference, submitted to JINS
Oral Health in 12- and 15-Year-Old Children in Serbia: A National Pathfinder Study.
The aim of the paper is to present the oral health profile of 12- and 15-year-old schoolchildren in Serbia. Basic Methods for Oral Health Surveys of the WHO were implemented to record: Decayed, Missing, and Filled Teeth/Surfaces Index (DMFT/DMFS), gingival bleeding, enamel fluorosis and other structural anomalies, dental erosion, dental trauma, and oral mucosal lesions. In addition, Silness and Löe plaque index and orthodontic status were assessed. A total of 36% of 12-year-olds and 22% of 15-year-olds in Serbia were caries-free. The mean DMFT was 2.32 ± 2.69 for 12-year-olds and 4.09 ± 3.81 for 15-year-olds. DMFT was made up largely by the decayed component. Gingival bleeding was present in 26% of examined 12-year-old and 18% of 15-year-old children. Dental plaque was observed in 63% of both 12- and 15-year-olds. Fluorosis, structural anomalies, dental erosion, dental trauma, and oral mucosal lesion were rarely detected. Low prevalence of malocclusions was found. Oral disease is still a common public health problem among schoolchildren in Serbia. A significant increase in the prevalence of caries disease between 12- and 15-year-old groups implies that preventive care for adolescents requires special attention. Corrective actions and reforms to the current school-based oral health prevention program are needed to further improve oral health in Serbian children
Radiation hard Depleted Monolithic Active Pixel Sensors with high-resistivity substrates
High Voltage/High resistivity Depleted Monolithic Active Pixel Sensors (HV/HR-DMAPS) is a technology which is becoming of great interest for high energy physics applications.With respect to hybrid pixel detectors the monolithic approach offers the main advantages of reduced material budget and production costs due to the absence of the bump bonding process. This aspect is important especially when large areas need to be covered as in the tracking detectors of the LHC experiments. Thus, the possibility of employing this technology in the outermost layers of the upgraded ATLAS pixel detector at the HL-LHC is being investigated.Different HR/HV-DMAPS prototypes have been recently developed for the future ATLAS Inner Tracker (ITk) with the aim of studying their radiation hardness and the feasibility of producing large area devices.The H35DEMO is a large area demonstrator chip for the ITk designed by KIT, IFAE and University of Liverpool and produced in AMS 350 nm HV-CMOS technology with an engineering run on four different substrate resistivities: 20, 80, 200 and 1000 . It consists of four large matrices, two of which include digital electronics and are thus fully monolithic. One, called CMOS matrix, has comparators made of CMOS transistors in the periphery only, while the other, called NMOS matrix, includes also comparators made of NMOS transistors directly in the pixels. The other two matrices have only analog front-end electronics and are meant to be coupled to ATLAS FE-I4 chips. All matrices feature pixels with a size of in which the analog electronics are embedded in a Deep N-WELL (DNWELL) also acting as collecting electrode.A Data Acquisition (DAQ) system was developed at IFAE to read out and test the monolithic matrices of the H35DEMO both in the laboratory and with beam test experiments. H35DEMO chips with a resistivity of 200 have been irradiated with reactor neutrons to a particle fluence of , the expected fluence for the outermost pixel layer of ITk. The monolithic CMOS matrix of the H35DEMO chip was extensively characterised before and after irradiation in beam tests at Fermilab and DESY, with proton and electron beams, respectively.Results after irradiation show good performance in terms of hit efficiency with thresholds of about 1800 e and a bias voltage of 150 V.Another production of monolithic HV-CMOS prototypes in LFoundry 150 nm technology (LF2) has been recently completed. It includes sensors with a similar DNWELL concept as the H35DEMO but with a smaller pixel size of . Preliminary measurements of leakage current of the LF2 chips have been preformed showing good agreement with what expected from the foundry process
Counting and integrating readout for direct conversion X-ray imaging: Concept, realization and first prototype measurements
A novel signal processing concept for X-ray imaging with directly converting pixelated semiconductor sensors is presented. The novelty of this approach compared to existing concepts is the combination of charge integration and photon counting in every single pixel. Simultaneous operation of both signal processing chains extends the dynamic range beyond the limits of the individual schemes and allows determination of the mean photon energy. Medical applications such as X-ray computed tomography can benefit from this additional spectral information through improved contrast and the ability to determine the hardening of the tube spectrum due to attenuation by the scanned object. A prototype chip in 0.35-micrometer technology has been successfully tested. The pixel electronics are designed using a low-swing differential current mode logic. Key element is a configurable feedback circuit for the charge sensitive amplifier which provides continuous reset, leakage current compensation and replicates the input signal for the integrator. This paper will discuss measurement results of the prototype structures and give details on the circuit design
AstroPix: novel monolithic active pixel silicon sensors for future gamma-ray telescopes
Space-based gamma-ray telescopes such as the Fermi Large Area Telescope have used single sided silicon strip detectors to track secondary charged particles produced by primary gamma-rays with high resolution. At the lower energies targeted by keV-MeV telescopes, two dimensional position information within a single detector is required for event reconstruction - especially in the Compton regime. This work describes the development of monolithic CMOS active pixel silicon sensors - AstroPix - as a novel technology for use in future gamma-ray telescopes. Based upon sensors (ATLASPix) designed for use in the ATLAS detector at the Large Hadron Collider, AstroPix has the potential to maintain high performance while reducing noise with low power consumption. This is achieved with the dual detection and readout capabilities in each CMOS pixel. The status of AstroPix development and testing, as well as outlook for future testing and application, will be presented
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