arXiv subjects

Yasuyuki Okumura

Publications and source records attributed to Yasuyuki Okumura.

4 recordsLinked to original sources

arXiv2026

Irradiation Studies of TGC Electronics Components for the ATLAS Experiment at High-Luminosity LHC

This paper evaluates the radiation tolerance of commercial off-the-shelf (COTS) electronics components for use in the Thin Gap Chamber (TGC) frontend electronics of the ATLAS experiment at the High-Luminosity LHC (HL-LHC). The ATLAS experiment has accumulated more than 450 fb^-1 of data as of 2025. Its luminosity upgrade, the HL-LHC scheduled to begin operation in 2030, will deliver 3000-4000 fb^-1 over ten years and lead to substantially higher radiation levels in detector electronics. The radiation levels for the TGC frontend electronics are estimated to be 4.1-7.3 Gy in terms of Total Ionizing Dose (TID) and 1.1-2.2 x 10^11 n_1MeV cm^-2 in terms of Non-Ionizing Energy Loss (NIEL). To evaluate component suitability under these conditions, TID tests were conducted using Cobalt-60 gamma rays at Nagoya University, and NIEL tests were performed with the Tandem Accelerator at Kobe University. Various COTS components, including SFP+ optical transceivers, clock jitter cleaners, optical fibers, voltage references, operational amplifiers, analog-to-digital converters, digital-to-analog converters, SD cards, flash memories, and low-dropout regulators, were tested and evaluated against the required radiation levels. The results demonstrate that all evaluated components meet the TID and NIEL tolerance requirements for application in the TGC frontend electronics at the HL-LHC.

physics.ins-det↗

arXiv2014

ATCA-based ATLAS FTK input interface system

The first stage of the ATLAS Fast TracKer (FTK) is an ATCA-based input interface system, where hits from the entire silicon tracker are clustered and organized into overlapping eta-phi trigger towers before being sent to the tracking engines. First, FTK Input Mezzanine cards receive hit data and perform clustering to reduce data volume. Then, the ATCA-based Data Formatter system will organize the trigger tower data, sharing data among boards over full mesh backplanes and optic fibers. The board and system level design concepts and implementation details, as well as the operation experiences from the FTK full-chain testing, will be presented.

physics.ins-det↗

arXiv2014

Prototype performance studies of a Full Mesh ATCA-based General Purpose Data Processing Board

High luminosity conditions at the LHC pose many unique challenges for potential silicon based track trigger systems. One of the major challenges is data formatting, where hits from thousands of silicon modules must first be shared and organized into overlapping eta-phi trigger towers. Communication between nodes requires high bandwidth, low latency, and flexible real time data sharing, for which a full mesh backplane is a natural solution. A custom Advanced Telecommunications Computing Architecture data processing board is designed with the goal of creating a scalable architecture abundant in flexible, non-blocking, high bandwidth board to board communication channels while keeping the design as simple as possible. We have performed the first prototype board testing and our first attempt at designing the prototype system has proven to be successful. Leveraging the experience we gained through designing, building and testing the prototype board system we are in the final stages of laying out the next generation board, which will be used in the ATLAS Level-2 Fast TracKer as Data Formatter, as well as in the CMS Level-1 tracking trigger R&D for early technical demonstrations.

physics.ins-det↗

arXiv2011

Top cross section measurements at ATLAS

Measurements of the production cross section of top-quark pairs ($t\bar t$) in $pp$ collisions at $\sqrt{s}$ = 7 TeV are presented using 35 \ipb\ of data recorded with the ATLAS detector at the Large Hadron Collider. Events are selected in the single lepton (electron or muon) and dilepton topologies with multi-jets, and large missing transverse energy. The result is $σ_{t\bar t} = 180 \pm 9\,\mathrm{(stat.)} \pm15 \,\mathrm{(syst.)} \pm 6 \,\mathrm{(lumi.)\,pb}$, which agrees with the Standard Model prediction.

hep-ex↗