1. |
- Amoroso, A., et al.
(författare)
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The CGEM-IT readout chain
- 2021
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Ingår i: Journal of Instrumentation. - : Institute of Physics Publishing (IOPP). - 1748-0221. ; 16:8
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Tidskriftsartikel (refereegranskat)abstract
- An innovative Cylindrical Gas Electron Multiplier (CGEM) detector is under construction for the upgrade of the inner tracker of the BESIII experiment. A novel system has been worked out for the readout of the CGEM detector, including a new ASIC, dubbed TIGER -Torino Integrated GEM Electronics for Readout, designed for the amplification and digitization of the CGEM output signals. The data output by TIGER are collected and processed by a first FPGA-based module, GEM Read Out Card, in charge of configuration and control of the front-end ASICs. A second FPGA-based module, named GEM Data Concentrator, builds the trigger selected event packets containing the data and stores them via the main BESIII data acquisition system. The design of the electronics chain, including the power and signal distribution, will be presented together with its performance.
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2. |
- Rolo, M. Da Rocha, et al.
(författare)
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A custom readout electronics for the BESIII CGEM detector
- 2017
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Ingår i: Journal of Instrumentation. - : IOP PUBLISHING LTD. - 1748-0221. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- For the upgrade of the inner tracker of the BESIII spectrometer, planned for 2018, a lightweight tracker based on an innovative Cylindrical Gas Electron Multiplier (CGEM) detector is now under development. The analogue readout of the CGEM enables the use of a charge centroid algorithm to improve the spatial resolution to better than 130 mu m while loosening the pitch strip to 650 mu m, which allows to reduce the total number of channels to about 10 000. The channels are readout by 160 dedicated integrated 64-channel front-end ASICs, providing a time and charge measurement and featuring a fully-digital output. The energy measurement is extracted either from the time-over-threshold (ToT) or the 10-bit digitisation of the peak amplitude of the signal. The time of the event is generated by quad-buffered low-power TDCs, allowing for rates in excess of 60 kHz per channel. The TDCs are based on analogue interpolation techniques and produce a time stamp (or two, if working in ToT mode) of the event with a time resolution better than 50 ps. The front-end noise, based on a CSA and a two-stage complex conjugated pole shapers, dominate the channel intrinsic time jitter, which is less than 5 ns r.m.s. The time information of the hit can be used to reconstruct the track path, operating the detector as a small TPC and hence improving the position resolution when the distribution of the cloud, due to large incident angle or magnetic field, is very broad. Event data is collected by an off-detector motherboard, where each GEM-ROC readout card handles 4 ASIC carrier FEBs (512 channels). Configuration upload and data readout between the off-detector electronics and the VME-based data collector cards are managed by bi-directional fibre optical links. This paper covers the design of a custom front-end electronics for the readout of the new inner tracker of the BESIII experiment, addressing the relevant design aspects of the detector electronics and the front-end ASIC for the CGEM readout, and reviewing the first silicon results of the chip prototype.
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3. |
- Di Gregorio, S., et al.
(författare)
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Highway traffic model based on cellular automata : Preliminary simulation results with congestion pricing considerations
- 2008
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Ingår i: Eur. Model. Simul. Symp., EMSS. - 8890073268 - 9788890073267 ; , s. 665-674
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Konferensbidrag (refereegranskat)abstract
- Cellular Automata are a reputable formal support for traffic modelling and simulation. STRATUNA is a Cellular Automata model for simulating the evolution of two/three lane highways. It encodes the wide specification of driver's response to the events in his sight range. Encouraging comparison between simulated events and their corresponding in the reality bring to the specification of a theoretical general model characterized by an increased expression power and a significantly deeper forecasting potential, whose application fields are numerous and varied. Fair results in flow forecasting lead to the implementation of an established cost system in which simulation directly provides cost forecasting in terms of congestion toll.
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4. |
- Karlsson, Hans O, et al.
(författare)
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Density of states of alternant cyclic polyenes (CH)(N) by a direct Lanczos method
- 1997
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Ingår i: International Journal of Quantum Chemistry. - 0020-7608 .- 1097-461X. ; 63:3, s. 719-728
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- A direct full configuration interaction approach, previously used for studying individual low-lying eigenvalues, is combined with iterative Lanczos calculations, in order to obtain global properties of large Hermitean Hamiltonian matrices. To this effect systematic generation of random start vectors is used to compute statistical approximations to the density of states (DOS). Applications for cyclic polyenes in order to illustrate the viability of the scheme modeled by correlated, tight-binding Pariser-Parr-Pople (PPP) Hamiltonians of increasing complexity are presented. The degree of correlation in the solutions is controlled by the parameter beta. Convergence properties of the DOS for N=10 and N=14 are studied varying the extent of correlation.
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