We present an analysis of the existing data on charmonium hadro-production based on non-relativistic QCD (NRQCD) calculations at the next-to-leading order (NLO). All the data on J/ψ and ψ(2S) ...production in fixed-target experiments and on pp collisions at low energy are included. We find that the amount of color-octet contribution needed to describe the data is about 1/10 of that found at the Tevatron.
The latest advances in the design and characterization of several pixel sensors developed to satisfy the very demanding requirements of the innermost layer of the SuperB Silicon Vertex Tracker will ...be presented in this paper. The SuperB machine is an electron positron collider operating at the ϒ(4S) peak to be built in the very near future by the Cabibbo Lab consortium. A pixel detector based on extremely thin, radiation hard devices able to cope with rate in the tens of MHz/cm2 range will be the optimal solution for the upgrade of the inner layer of the SuperB tracking system. At present several options with different levels of maturity are being investigated to understand advantages and potential issues of the different technologies: thin hybrid pixels, Deep N-Well CMOS MAPS, INMAPS CMOS MAPS featuring a quadruple well and high resistivity substrates and CMOS MAPS realized with Vertical Integration technology. The newest results from beam test, the outcomes of the radiation damage studies and the laboratory characterization of the latest prototypes will be reported.
Modern experiments search for extremely rare processes hidden in much larger background levels. As the experiment complexity, the accelerator backgrounds and luminosity increase we need increasingly ...exclusive selections to efficiently select the rare events inside the huge background. We present a fast, high-quality, track-based event selection for the self-triggered SLIM5 silicon telescope. This is an R&D experiment whose innovative trigger will show that high rejection factors and manageable trigger rates can be achieved using fine-granularity, low-material tracking detectors.
The SuperB asymmetric e + e - collider has been designed to deliver a luminosity greater than 10 36 cm -2 s -1 maintaining moderate beam currents. Comparing to current B-Factories, the reduced ...center-of-mass boost of the SuperB machine requires an improved vertex resolution to allow precision measurements sensitive to New Physics. Therefore the SuperB Silicon Vertex Tracker will be equipped with an innermost Layer0 with a radius of about 1.5 cm, high granularity, low material budget and able to withstand a background rate of several MHz/cm 2 . We report on the status of the R&D on the different options under study for the Layer0: DNW MAPS, hybrid pixels and thin pixels developed with vertical integration technology.
A conventional transmission electron microscope is used as a versatile optical bench in a setup where a pixel recording system, sensitive to single electrons, replaces the final viewing screen. Our ...detector is based on a custom CMOS chip of 4096 monolithic active pixels designed for applications in vertex detectors of future collider experiments. The chip is equipped with a fast read-out chain able to manage up to 10 6 frames per second. This capability permitted to collect high statistics samples of single electron events within a time interval where the stable operations and the coherence conditions of the microscope were guaranteed. The microscope was configured with an accelerating potential of 60 kV, hence leading to 60 keV electrons. The large fraction of empty events made possible to obtain measurements of the time distribution of electron arrivals and this is what really characterizes this work. In fact, for the first time, conventional interference patterns have been split into single-electron frames according to the time of arrival. In particular, the 4096-pixel sensor has been used to collect diffraction patterns of a single wire, a carbon grating and eventually to reproduce the Young-Feynman two-slit experiment with single electrons instead of light. The experiment has been carried out by inserting two nanometric slits-two 100 × 1500 nm slits, 500 nm spaced apart-in the microscope that provided the electron beam source and the electro-optical lenses for projecting and focusing the pattern on the sensor. The fast readout of the sensor allowed us to record single-electron frames, spaced by several empty frames, and this is an improvement over past single-electron interference works. In this way the time distribution of the single electron arrivals has been measured with a timing resolution of 160 μs. This research might also open new detector investigation and development and characterization of pixel sensors.
The computing cluster built at Bologna to provide the LHCb Collaboration with a powerful Monte Carlo production tool is presented. It is a performance oriented Beowulf-class cluster, made of rack ...mounted commodity components, designed to minimize operational support requirements and to provide full and continuous availability of the computing resources. In this paper we describe the architecture of the cluster, and discuss the technical solutions adopted for each specialized sub-system.
The SLIM5 low mass silicon tracker demonstrator Bettarini, S.; Ratti, L.; Rizzo, G. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2010, Letnik:
623, Številka:
3
Journal Article
Recenzirano
A low material budget silicon demonstrator has been tested by the SLIM5 collaboration with 12
GeV/
c protons at the PS-T9 beam line at CERN. Two devices were placed inside a reference telescope and ...their characteristics were measured. The first was a 4k-Pixel Matrix of Deep N Well MAPS, developed in a 130
nm CMOS technology, providing digital sparsified readout. The other one was a high resistivity double-sided silicon detector, with short strips at a
45
∘
angle to the detector's edge, read out by the FSSR2 chip. In this paper we describe the main features of both sensors. The primary goal of the test was to measure the efficiency and the resolution of the DUTs under different conditions of threshold setting and incident angle of the impinging particles. The data-driven approach of the readout chips has been fully exploited by the DAQ system to take data with a track-based level-1 trigger provided by a pattern matching algorithm with very low latency.
The antineutron–proton total cross section has been measured in the low momentum range 50–400 MeV/
c (below 100 MeV/
c for the first time). The measurement was performed at LEAR (CERN) by the OBELIX ...experiment, thanks to its unique antineutron beam facility. A thick target transmission technique has been used. The measured total cross section shows an anomalous behaviour below 100 MeV/
c. A dominance of the isospin
I=0 channel over the
I=1 one at low energy is clearly deduced.
A 4096-pixel MAPS device with on-chip data sparsification Gabrielli, A.; Batignani, G.; Bettarini, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
06/2009, Letnik:
604, Številka:
1
Journal Article
Recenzirano
A prototype of a mixed-mode ASIC composed of a fast readout architecture that interfaces with a matrix of 4096 Monolithic Active Pixel Sensor (MAPS) was fabricated via STM 130
nm CMOS technology. ...Groups of 4×4 pixels form a macro-pixel (MP). The readout architecture is parallel and could overcome the readout speed limit of big matrices. As the output port can only accept one-hit information at a time, an internal queuing system has been provided to face high hit-rate conditions. The ASIC can work in two different manners as it can be connected to an actual full-custom matrix of MAPS or to a digital matrix emulator composed of standard cells, for testing facilities. For both operating modes a slow-control phase is required to load the chip configuration. Previous versions of similar ASICs were designed and tested. The work is aimed at improving the design of MAPS detectors with an on-chip fast sparsification system, for particle tracking, to match the requirements of future high-energy physics experiments. The readout architecture implemented is data driven extending the flexibility of the system to be also used in first level triggers on tracks in vertex detectors. Preliminary simulations and tests indicate that the readout system can cope with an average hit-rate up to 100
MHz/cm
2 if a master clock of 80
MHz is used, while maintaining an overall efficiency over 99%.
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