This paper investigates wireless-powered cell-free systems, in which the users send their uplink data signal while simultaneously harvesting energy from network nodes and user terminals - including ...the transmitting user terminal itself - by performing self-energy recycling. In this rather general setting, a closed-form lower bound of the amount of harvested energy and the achieved signal-to-interference-plus-noise ratio expressions are derived. Then, to improve the energy efficiency, we formulate the problem of minimizing the users' battery energy usage while satisfying minimum data rate requirements. Due to the non-convexity of the problem, a novel alternating optimization algorithm is proposed, and its proof of convergence is provided. Finally, numerical results show that the proposed method is more efficient than a state-of-art algorithm in terms of battery energy usage and outage rate.
The Time-Of-Flight (TOF) detector of the ALICE experiment at the CERN LHC is based on Multi-gap Resistive Plate Chambers (MRPCs) technology. During the 2009-2013 data taking the TOF system had very ...stable operations with a total time resolution of 80ps. Details of the different calibration procedures and performance with data from collisions at the LHC will be described.
The AQUA-RICH project Antonioli, P.
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2020, Letnik:
970
Journal Article
Recenzirano
The AQUA-RICH project, a long baseline and atmospheric neutrino experiment proposed by Tom Ypsilantis during the last decade of the last century, is briefly reviewed. The detector proposal is ...discussed within the context of the searches for neutrino oscillations at that time and as part of the longstanding seminal ideas and key contributions provided by Tom Ypsilantis in the development of the RICH technique.
ABSTRACT The Large Volume Detector (LVD) has been continuously taking data since 1992 at the INFN Gran Sasso National Laboratory. The LVD is sensitive to neutrino bursts from gravitational stellar ...collapses with full detection probability over the Galaxy. We have searched for neutrino bursts in LVD data taken over 7,335 days of operation. No evidence of neutrino signals has been found between 1992 June and 2013 December. The 90% C.L. upper limit on the rate of core collapse and failed supernova explosions out to distances of 25 kpc is found to be 0.114 yr−1.
SARS-CoV-2 can reportedly exist on inanimate surfaces for a long duration, but there is limited data available from Italian COVID-19 hospital wards, especially for non-intensive care units hosting ...patients that do not require mechanical ventilation. Identification of the extent of environmental contamination can help in understanding possible virus transmission routes, limit hospital infections and protect healthcare workers. Thus, we investigated virus contamination on surfaces of the acute COVID-19 ward of an Italian hospital.
Ward surfaces, including four points inside and six points outside the patients' rooms were sampled by swabs, seven hours after routine sanitation. To minimize the risk of underestimation of virus detection, two different sensitive molecular methods were used comparatively, and specific internal controls were added to enhance the efficiency of all the analysis steps.
SARS-CoV-2 contamination was detected in only three out of all the collected samples, i.e., on two floors and one-bathroom sink, likely reflecting aerosol and saliva contamination, respectively. The overall level of contamination was low, and the floors exhibited a very low level of SARS-CoV-2 presence, evidenced by only one of the two methods used.
The existence of SARS-CoV-2 on hospital surfaces may be limited, although it was reported to persist for a longer duration on surfaces under controlled laboratory conditions. Thus, effective transmission of SARS-CoV-2 by surfaces/fomites within the hospital ward may be a rare event. However, the results highlight the importance of assessing method sensitivity and including controls when investigating low-level virus contamination so as to avoid the risk of underestimation of virus presence.
Various experiments are searching for detectors that can cover large areas (as in the present LHC experiments) with excellent timing performances and insensitivity to magnetic field. A detector based ...on scintillators coupled to SiPM can fulfil these requirements. SiPMs are indeed replacing the standard PhotoMultiplier technology thanks to the many advantages, with the corresponding possibility to achieve also higher segmentations in calorimetry or other applications. Also in view of future colliders experiments like HL-LHC or FCC or medical applications like TOF-PET, an important R&D on timing performances of SiPMs-scintillator detectors has begun, with the goal of including them in the list of possible 4-D tracking-timing devices.
An R&D on SiPM coupled to scintillator time resolution has been performed in a cosmic ray setup. Different kind of SiPMs, geometries of SiPMs coupled to the scintillator and different size of scintillator have been also studied. A time resolution of ∼69 ps, comprehensive of the full electronic chain, from the front-end to the readout electronics, has been achieved with SiPMs coupled to a 2x2x3 cm3 plastic scintillator.
In order to cope with the increased luminosity that the European Organization for Nuclear Research large hadron collider accelerator will provide after Long Shutdown 2 (2019- 2020), the a large ion ...collider experiment (ALICE) Time-Of-Flight (TOF) readout board data readout module is currently being redesigned. As a first step toward the final design, a test board hosting a Microsemi Igloo2 field-programmable gate array (FPGA), the radiation-hard Application-Specified Integrated Circuit (ASIC) gigabit transceiver ASIC (GBTX), and the optical transceiver versatile link transceiver (VTRX) has been designed and extensively tested. The basic idea is to use the GBTX ASIC for performing data transmission, trigger distribution, and clock forwarding toward the front-end electronics. Slow control links are implemented via an on-board advanced risc machine processor Ethernet link and via a 1.25-Gbps optical fiber using the Igloo2 FPGA internal serializer/deserializer. The board is going to work in a moderately hostile environment, having to face a total dose of 0.13 krads in ten years and a flux of 0.26 kHz/cm 2 of hadrons with energy above 20 MeV. The test board has extensively been tested with a special attention dedicated to the Igloo2-GBTX-VTRX devices. An upper bound estimation of the optical link bit error rate lower than 10 -14 is given, together with a measurement of the jitter of the GBTX output clock (around 55.3 ps peak-to-peak value), since this is a very crucial parameter for the TOF detector. The performances obtained by connecting the test board to a computer using the standard ALICE data acquisition board (named C-RORC) are also reported.
Abstract
The direct response of Silicon PhotoMultipliers being
traversed by a MIP charged particle have been studied in a
systematic way for the first time. Using beam test data, time
resolution and ...the crosstalk probability have been measured. A
characterization of the SiPM by means of a laser beam is also
reported. The results obtained for different sensors indicate a
measured time resolution around 40–70 ps. Although particles are
expected to traverse only one SPAD per event, crosstalk measurements
on different sensors indicate an unexpected higher value with
respect to the one related to the sensor noise.
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