53769716
On the integration of high performance ATM-based event builders
A first demonstrator has shown encouraging results for the use of Asynchronous Transfer Mode (ATM) switching networks in the implementation of high performance parallel event builders. Our present goal is to show that the integration of event builders, including the implementation of the source and destination functions and the bandwidth adaptation to the switching network, can be realized with commercially available products and that good performance can be achieved. We shall review some critical issues, present results from performance measurements and analyse the overheads.
118645473
The topological second-level trigger of the H.E.S.S. phase 2 telescope
H.E.S.S is an array of atmospheric Cherenkov telescopes dedicated to GeV-TeV γ-ray astronomy. The original array has been in operation since the beginning of 2004. It is composed of four 12-meter diameter telescopes. The installation of a fifth 28-meter diameter telescope is being completed. This telescope will operate both in stereoscopic mode and in monoscopic mode i.e. without a coincident detection on the smaller telescopes. A second-level trigger system is needed to supress spurious triggers of the 28-meter telescope when operated in monoscopic mode. This paper gives the motivation and principle of the second-level trigger. The principle of operation is illustrated by an example algorithm. The hardware implementation of the second level trigger system of H.E.S.S. phase 2 is described and its expected performances are then evaluated.
24114639
The Level 2 Trigger of the H.E.S.S. 28 Meter Cherenkov Telescope
The High-energy Stereoscopic System (H.E.S.S.) is an array of atmospheric Cherenkov telescopes dedicated to GeV-TeV γ ray astronomy. Four 12 meter diameter telescopes (CT) are currently in operation and a fifth 28 meter diameter telescope (LCT) should be completed by 2011. This will lower the system's energy threshold in stereoscopy down to ≈50 GeV. Concurrently, the LCT will also be used to detect monoscopic lower energy showers without a coincident detection on the smaller telescopes. This is made possible thanks to the higher sensitivity and the faster electronics of the LCT. But lowering the L1 trigger conditions on the LCT results in a larger number of spurious background detections the reduction of which motivates the second level trigger system of the LCT. An efficient L2 selection algorithm was designed based on intensive off line simulations of air shower images from different background events and their morphological differences as seen by the LCT. The present contribution reports on the flexible and reconfigurable hardware solution designed for the L2 trigger, and on the real-time implementation of the proposed L2 algorithm.
121719013
Electrical characteristics of silicon pixel detectors
Prototype sensors for the ATLAS silicon pixel detector have been electrically characterized. The current and voltage characteristics, charge-collection efficiencies, and resolutions have been examined. Devices were fabricated on oxygenated and standard detector-grade silicon wafers. Results from prototypes which examine p-stop and standard and moderated p-spray isolation are presented for a variety of geometrical options. Some of the comparisons relate unirradiated sensors with those that have received fluences relevant to LHC operation.
109862390
Test system for the production of the Atlas Tile Calorimeter front-end electronics
Abstract The Atlas hadronic Tile Calorimeter front-end electronics is fully included in the so-called “super-drawers”. The 256 super-drawers needed for the entire calorimeter are assembled and extensively tested in Clermont-Ferrand before being sent to CERN to be inserted in the calorimeter modules. A mobile system has been developed to perform a complete test of the super-drawers during their insertion.
64504728
MAREBO: A full radhard pixel detector prototype for ATLAS