Design and performance of the level 1 calorimeter trigger for the BABAR detector

Citation
Pd. Dauncey et al., Design and performance of the level 1 calorimeter trigger for the BABAR detector, IEEE NUCL S, 48(3), 2001, pp. 541-546
Citations number
6
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science","Nuclear Emgineering
Journal title
IEEE TRANSACTIONS ON NUCLEAR SCIENCE
ISSN journal
0018-9499 → ACNP
Volume
48
Issue
3
Year of publication
2001
Pages
541 - 546
Database
ISI
SICI code
0018-9499(200106)48:3<541:DAPOTL>2.0.ZU;2-A
Abstract
Since May 1999 the BABAR detector has been taking data at the PEP-II asymme tric electron-positron collider at the Stanford Linear Accelerator Center, CA. This experiment requires a very large data sample and the PEP-Il accele rator uses intense beams to deliver the high collision rates needed. This p oses a severe challenge to the BABAR trigger system, which must reject the large rate of background signals resulting from the high beam currents whil st accepting the collisions of interest with very high efficiency. One of t he systems that performs this task is the Level 1 Calorimeter Trigger, whic h identifies energy deposits left by particles in the BABAR calorimeter. It is a digital, custom, fixed latency system which makes heavy use of high-s peed FPGA devices to allow flexibility in the choice of data filtering algo rithms. Results from several intermediate processing stages are read out, a llowing the selection algorithm to be fully analyzed and optimized offline. In addition, the trigger is monitored in real time by sampling these data and cross-checking each stage of the trigger calculation against a software model. The design, implementation, construction and performance of the Lev el 1 Calorimeter Trigger during the first year of BABAR operation are prese nted.