Fast tracker performance using the new 'variable resolution associative memory' for ATLAS

Tomoya Iizawa*

*この研究の対応する著者

    研究成果: Conference contribution

    1 被引用数 (Scopus)

    抄録

    The Fast Tracker (FTK) for the ATLAS trigger is a state-of-the-art online processor that tackles and solves the full track reconstruction problem at a hadron collider. We describe an important advancement for the Associative Memory device (AM). The AM is a VLSI processor for pattern recognition based on Content Addressable Memory (CAM) architecture. Pattern matching is carried out by finding track candidates in coarse resolution 'roads'. A large AM bank stores all trajectories of interest, called 'patterns', for a given detector resolution. The AM extracts roads compatible with a given event at each level-1 read-out. Two important variables characterize the quality of the AM bank: its 'coverage' and the level of fake roads. The coverage, which describes the geometric efficiency of a bank, is defined as the probability for a track to match at least one pattern in the bank. To optimize the efficiency the easiest way is to increase the road size, keeping the number of patterns low and the system cheap. But this has a bad performance at high luminosity, where large roads are sensitive to the combinatoric effect, pushing on the contrary to use smaller roads and more patterns and making the system extremely expensive. We propose an elegant solution to this problem: the 'variable resolution patterns'. Each detector layer within a pattern will be able to use the optimal width. Using a 'don't care' feature (inspired from ternary CAMs) to increase the width when that is more appropriate. In other words we can use patterns of variable shape. We will show how this reduces the number of fake roads, while keeping the efficiency high and avoiding excessive bank size due to the reduced width.

    本文言語English
    ホスト出版物のタイトル2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record, NSS/MIC 2012
    ページ1392-1395
    ページ数4
    DOI
    出版ステータスPublished - 2012 12 1
    イベント2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record, NSS/MIC 2012 - Anaheim, CA, United States
    継続期間: 2012 10 292012 11 3

    出版物シリーズ

    名前IEEE Nuclear Science Symposium Conference Record
    ISSN(印刷版)1095-7863

    Conference

    Conference2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record, NSS/MIC 2012
    国/地域United States
    CityAnaheim, CA
    Period12/10/2912/11/3

    ASJC Scopus subject areas

    • 放射線
    • 核物理学および高エネルギー物理学
    • 放射線学、核医学およびイメージング

    フィンガープリント

    「Fast tracker performance using the new 'variable resolution associative memory' for ATLAS」の研究トピックを掘り下げます。これらがまとまってユニークなフィンガープリントを構成します。

    引用スタイル