49541949
Polarization of a stored beam by spin filtering
The PAX Collaboration has successfully performed a spin-filtering experiment with protons at the COSY-ring. The measurement allowed the determination of the spin-dependent polarizing cross section, ...
2503701
GPUs for real-time processing in HEP trigger systems
We describe a pilot project for the use of Graphics Processing Units (GPUs) for online triggering applications in High Energy Physics (HEP) experiments. Two major trends can be identified in the development of trigger and DAQ systems for HEP experiments: the massive use of general-purpose commodity systems such as commercial multicore PC farms for data acquisition, and the reduction of trigger levels implemented in hardware, towards a pure software selection system (trigger-less). The very innovative approach presented here aims at exploiting the parallel computing power of commercial GPUs to perform fast computations in software both at low- and high-level trigger stages. General-purpose computing on GPUs is emerging as a new paradigm in several fields of science, although so far applications have been tailored to the specific strengths of such devices as accelerator in offline computation. With the steady reduction of GPU latencies, and the increase in link and memory throughputs, the use of such devices for real-time applications in high-energy physics data acquisition and trigger systems is becoming very attractive. We discuss in details the use of online parallel computing on GPUs for synchronous low-level trigger with fixed latency. In particular we show preliminary results on a first test in the NA62 experiment at CERN. The use of GPUs in high-level triggers is also considered, the ATLAS experiment (and in particular the muon trigger) at CERN will be taken as a study case of possible applications.
110168648
The front end electronics of the NA62 Gigatracker: Challenges, design and experimental measurements
The beam spectrometer of the NA62 experiment consists of 3 Gigatracker (GTK) stations. Each station comprises a pixel detector of 16 cm 2 active area made of an assembly of 10 readout ASICs bump bonded to a 200 μ m thick pixel silicon sensor, comprising 18000 pixels of 300 μ m × 300 μ m . The main challenge of the NA62 pixel GTK station is the combination of an extremely high kaon/pion beam rate, where the intensity in the center of the beam reaches up to 1.5 Mhit s − 1 mm − 2 together with an extreme time resolution of 100 ps . To date, it is the first silicon tracking system with this time resolution. To face this challenge, the pixel analogue front end has been designed with a peaking time of 4 ns , with a planar silicon sensor operating up to 300 V over depletion. Moreover, the radiation level is severe, 2 × 10 14 1 MeV n e q . cm − 2 per year of operation. Easy replacement of the GTK stations is foreseen as a design requirement. The amount of material of a single station should also be less than 0.5% X 0 to minimize the background, which imposes strong constraints on the mechanics and the cooling system. We report upon the design and architecture of the 2 prototype demonstrator chips both designed in 130 nm CMOS technology, one with a constant fraction discriminator and the time stamp digitisation in each pixel (In-Pixel), and the other with a time-over-threshold discriminator and the processing of the time stamp located in the End of Column (EoC) region at the chip periphery. Some preliminary results are presented.
55444434
The NA62 experiment at CERN.
The rare decays K+→ π+νν are excellent processes to make tests of new physics at the highest scale complementary to LHC thanks to their theoretically cleanliness. The NA62 experiment at CERN SPS aims to collect about 100 of such events in two years of data taking, keeping the background at the level of 10%. The physics motivation, experimental technique and the status of the construction of the experiment will be presented.
122866398
The NA62 Gigatracker pixel detector system
The silicon tracker for the NA62 experiment has to provide both a time resolution of 150 ps rms and a space resolution of about 100 mu m rms. These challenging specifications require the development of a new readout electronics in order to address the problem of measuring the tracks arrival time with such a high channel density. Moreover, the high particle density (up to 1.5 MHz/mm(2) in the center and 0.8-1 GHz in total) requires a high speed measurement and data transmission in order to keep the dead time below 1%. (C) 2009 Elsevier B.V. All rights reserved.
118676553
Experimental proposal to study the excess at Mjj=150 GeV presented by CDF at Fermilab
We propose an experimental test to verify the unexpected excess at Mjj=150GeV presented by the CDF collaboration in the invariant mass distribution of jet pairs produced in association with a W boson. 
We propose a formation experiment in which the energy range of the Mjj excess is scanned with proton-antiproton interactions at the Tevatron.
118277826
The Site of the ASTRI SST-2M Telescope Prototype
ASTRI is a Flagship Project financed by the Italian Ministry of Education, University and Research, and led by the Italian National Institute of Astrophysics, INAF. Primary goal of the ASTRI project is the design and production of an end-to-end prototype of Small Size Telescope for the CTA (Cherenkov Telescope Array) in a dual-mirror configuration (SST-2M) equipped with a camera at the focal plane composed by an array of Silicon Photo-Multipliers and devoted to the investigation of the highest gamma-ray energy band. The ASTRI SST-2M prototype will be placed at the INAF M.G. Fracastoro observing station in Serra La Nave on the Etna Mountain near Catania, Italy. After the verification tests, devoted to probe the technological solutions adopted, the ASTRI SST-2M prototype will perform scientific observations on the Crab Nebula and on some of the brightest TeV sources. Here we present the Serra La Nave site, its meteorological and weather conditions, the sky darkness and visibility, and the complex of auxiliary instrumentation that will be used on site to support the calibration and science verification phase as well as the regular data reconstruction and analysis of the ASTRI SST-2M prototype.
118604795
The Soft X-ray Imager on board EXIST
The Soft X-ray Imager (SXI) is one of the three instruments on board EXIST, a multi-wavelength observatory in charge of performing a global survey of the sky in hard X-rays searching for Super-massive Black Holes (Grindlay & Natalucci, these Proceedings). One of the primary objectives of EXIST is also to study with unprecedented sensitivity the most unknown high energy sources in the Universe, like high redshift GRBs, which will be pointed promptly by the Spacecraft by autonomous trigger based on hard X-ray localization on board. The presence of a soft X-ray telescope with an effective area of about 950cm2 in the energy band 0.2-3 keV and extended response up to 10 keV will allow to make broadband studies from 0.1 to 600 keV. In particular, investigations of the spectra components and states of AGNs and monitoring of variability of sources, study of the prompt and afterglow emission of GRBs since the early phases, which will help to constrain the emission models and finally, help the identification of sources in the EXIST hard X-ray survey and the characterization of the transient events detected. SXI will also perform surveys: a scanning survey with sky coverage 2pi and a limiting flux of 5x10^(-14) cgs plus other serendipitous.
116982610
The ASTRI SST-2M Prototype: Structure and Mirror
The next generation of IACT (Imaging Atmospheric Cherenkov Telescope) will explore the uppermost end of the VHE (Very High Energy) domain up to about few hundreds of TeV with unprecedented sensibility, angular resolution and imaging quality. To this end, INAF (Italian National Institute of Astrophysics) is currently developing a scientific and technological telescope prototype for the implementation of the CTA (Cherenkov Telescope Array) observatory. ASTRI (Astrofisica con Specchi a Tecnologia Replicante Italiana) foresees the full design, development, installation and calibration of a Small Size 4 meter class Telescope. The telescope, named SST-2M, is based on an aplanatic, wide field, double reflection optical layout in a Schwarzschild-Couder configuration. In this paper we report about the technological solutions adopted for the telescope and for the mirrors. In particular the structural and electro-mechanical design of the telescope and the results on the optical performance derived after the development of a prototype of the segments that will be assembled to form the primary mirror.