49 research outputs found

    The Data Acquisition System for the KOTO Experiment

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    We developed and built a new system of readout and trigger electronics, based on the waveform digitization and pipeline readout, for the KOTO experiment at J-PARC, Japan. KOTO aims at observing the rare kaon decay KL→π0ννˉK_{L}\rightarrow\pi^{0}\nu\bar{\nu}. A total of 4000 readout channels from various detector subsystems are digitized by 14-bit 125-MHz ADC modules equipped with a 10-pole Bessel filter in order to reduce the pile-up effects. The trigger decision is made every 8-ns using the digitized waveform information. To avoid dead time, the ADC and trigger modules have pipelines in their FPGA chips to store data while waiting for the trigger decision. The KOTO experiment performed the first physics run in May 2013. The data acquisition system worked stably during the run.Comment: 5 pages,12 figures, Transactions on Nuclear Science, Proceedings of the 19th Real Time Conference, Preprin

    A Scintillator Beam Monitor for Real-Time FLASH Radiotherapy

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    FLASH Radiotherapy (RT) is a potentially new cancer radiotherapy technique where an entire therapeutic dose is delivered in about 0.1 s and at ~1000 times higher dose rate than in conventional RT. For clinical trials to be conducted safely, precise and fast beam monitoring that can generate an out-of-tolerance beam interrupt is required. A FLASH Beam Scintillator Monitor (FBSM) is being developed based in part on two novel proprietary scintillator materials: an organic polymeric material (PM) and inorganic hybrid (HM). The FBSM provides large area coverage, low mass profile, linear response over a broad dynamic range, radiation tolerance, and real-time analysis IEC-compliant fast beam-interrupt signal. This paper includes the design concept and test results from prototype devices in radiation beams that include heavy ions, low energy protons at nA currents, FLASH level dose per pulse electron beams, and in a hospital radiotherapy clinic with electron beams. Results include image quality, response linearity, radiation hardness, spatial resolution, and real-time data processing. PM and HM scintillator exhibited no measurable drop in signal after a cumulative dose of 9 kGy and 20 kGy respectively. HM showed a small -0.02%/kGy signal decrease after a 212 kGy cumulative dose resulting from continuous exposure for 15 minutes at a high FLASH dose rate of 234 Gy/s. These tests established the linear response of the FBSM with respect to beam currents, dose per pulse, and material thickness. Comparison with commercial Gafchromic film indicates that the FBSM produces a high resolution 2D beam image and can reproduce a nearly identical beam profile, including primary beam tails. At 20 kfps or 50 microsec/frame, the real-time FPGA based computation and analysis of beam position, beam shape, and beam dose takes < 1 microsec.Comment: 15 pages, 9 figure

    The Data Acquisition System for the KOTO Detector

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    AbstractThe Data Acquisition (DAQ) for the KOTO detector is designed around a 14-bit 125MHz ADC module, which measures the energy and the time of photomultiplier pulses from about 4000 readout channels. The Trigger has a two-tiered design, with a first level decision based on the time-aligned energy sum over the entire calorimeter and a second level decision based on clustering and in-time veto signal rejection. Data accepted by the second level trigger are read out via Gigabit Ethernet and passed to a computer farm for event building and data storage

    Measurement of the Lifetime Difference Between B_s Mass Eigenstates

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    We present measurements of the lifetimes and polarization amplitudes for B_s --> J/psi phi and B_d --> J/psi K*0 decays. Lifetimes of the heavy (H) and light (L) mass eigenstates in the B_s system are separately measured for the first time by determining the relative contributions of amplitudes with definite CP as a function of the decay time. Using 203 +/- 15 B_s decays, we obtain tau_L = (1.05 +{0.16}/-{0.13} +/- 0.02) ps and tau_H = (2.07 +{0.58}/-{0.46} +/- 0.03) ps. Expressed in terms of the difference DeltaGamma_s and average Gamma_s, of the decay rates of the two eigenstates, the results are DeltaGamma_s/Gamma_s = (65 +{25}/-{33} +/- 1)%, and DeltaGamma_s = (0.47 +{0.19}/-{0.24} +/- 0.01) inverse ps.Comment: 8 pages, 3 figures, 2 tables; as published in Physical Review Letters on 16 March 2005; revisions are for length and typesetting only, no changes in results or conclusion

    Shaking table tests and numerical analyses on a scaled dry-joint arch undergoing windowed sine pulses

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    The damages occurred during recent seismic events have emphasised the vulnerability of vaulted masonry structures, one of the most representative elements of worldwide cultural heritage. Although a certain consensus has been reached regarding the static behaviour of masonry arches, still more efforts are requested to investigate their dynamic behaviour. In this regard, the present paper aims to investigate the performance of a scaled dry-joint arch undergoing windowed sine pulses. A feature tracking based measuring technique was employed to evaluate the displacement of selected points, shading light on the failure mechanisms and gathering data for the calibration of the numerical model. This was built according to a micro-modelling approach of the finite element method, with voussoirs assumed very stiff and friction interface elements. Comparisons with existing literature are also stressed, together with comments about scale effects.This work was partly financed by FEDER funds through the Competitivity Factors Operational Programme-COMPETE and by national funds through FCT-Foundation for Science and Technology within the scope of the Project POCI-01-0145-FEDER-007633.info:eu-repo/semantics/publishedVersio

    The future of road transport

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    A perfect storm of new technologies and new business models is transforming not only our vehicles, but everything about how we get around, and how we live our lives. The JRC report “The future of road transport - Implications of automated, connected, low-carbon and shared mobility” looks at some main enablers of the transformation of road transport, such as data governance, infrastructures, communication technologies and cybersecurity, and legislation. It discusses the potential impacts on the economy, employment and skills, energy use and emissions, the sustainability of raw materials, democracy, privacy and social fairness, as well as on the urban context. It shows how the massive changes on the horizon represent an opportunity to move towards a transport system that is more efficient, safer, less polluting and more accessible to larger parts of society than the current one centred on car ownership. However, new transport technologies, on their own, won't spontaneously make our lives better without upgrading our transport systems and policies to the 21st century. The improvement of governance and the development of innovative mobility solutions will be crucial to ensure that the future of transport is cleaner and more equitable than its car-centred present.JRC.C.4-Sustainable Transpor
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