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Ahmed, A.

Publications and source records attributed to Ahmed, A..

At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Performance of prototype GE1/1 chambers for the CMS muon spectrometer upgrade

The high-luminosity phase of the Large Hadron Collider (HL-LHC) will result in ten times higher particle background than measured during the first phase of LHC operation. In order to fully exploit the highly-demanding operating conditions during HL-LHC, the Compact Muon Solenoid (CMS) Collaboration will use Gas Electron Multiplier (GEM) detector technology. The technology will be integrated into the innermost region of the forward muon spectrometer of CMS as an additional muon station called GE1/1. The primary purpose of this auxiliary station is to help in muon reconstruction and to control level-1 muon trigger rates in the pseudo-rapidity region 1.6 ≤ |η| ≤ 2.2. The new station will contain trapezoidal-shaped GEM detectors called GE1/1 chambers. The design of these chambers is finalized, and the installation is in progress during the Long Shutdown phase two (LS-2) that started in 2019. Several full-size prototypes were built and operated successfully in various test beams at CERN. Here, we describe performance measurements such as gain, efficiency, and time resolution of these prototype chambers, developed after years of R&D, and summarize their behavior in different gas compositions as a function of the applied voltage.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2019

Layout and assembly technique of the GEM chambers for the upgrade of the CMS first muon endcap station

Triple-GEM detector technology was recently selected by CMS for a part of the upgrade of its forward muon detector system as GEM detectors provide a stable operation in the high radiation environment expected during the future High-Luminosity phase of the Large Hadron Collider (HL-LHC). In a first step, GEM chambers (detectors) will be installed in the innermost muon endcap station in the 1.6<|η|<2.2 pseudo-rapidity region, mainly to control level-1 muon trigger rates after the second LHC Long Shutdown. These new chambers will add redundancy to the muon system in the η-region where the background rates are high, and the bending of the muon trajectories due to the CMS magnetic field is small. A novel construction technique for such chambers has been developed in such a way where foils are mounted onto a single stack and then uniformly stretched mechanically, avoiding the use of spacers and glue inside the active gas volume. We describe the layout, the stretching mechanism and the overall assembly technique of such GEM chambers.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
NASA NTRS2006

Terrestrial Planet Finder Interferometer Technology Status and Plans

A viewgraph presentation on the technology status and plans for Terrestrial Planet Finder Interferometer is shown. The topics include: 1) The Navigator Program; 2) TPF-I Project Overview; 3) Project Organization; 4) Technology Plan for TPF-I; 5) TPF-I Testbeds; 6) Nulling Error Budget; 7) Nulling Testbeds; 8) Nulling Requirements; 9) Achromatic Nulling Testbed; 10) Single Mode Spatial Filter Technology; 11) Adaptive Nuller Testbed; 12) TPF-I: Planet Detection Testbed (PDT); 13) Planet Detection Testbed Phase Modulation Experiment; and 14) Formation Control Testbed.

Terrestrial Planet Finder (TPF)↗
NASA NTRS2002

Precision guidance and control for formation flying spacecraft

The authors provide an overview of the challenges that must be overcome to fully realize the increased science returns that formations engender. The challenges are separated into six categories that span hardware, software and theory. The contribution of this paper is that it clearly delineates each category, listing detailed problems that must be solved.

guidance control formation flying↗
NASA NTRS2002

The StarLight mission: a formation-flying stellar interferometer

The StarLight mission is designed to validate the technologies of formation flying and stellar interferometry in space. The mission consists of two spacecraft in an earth-trailing orbit that formation fly over relative ranges of 40 to 600 m to an accuracy of 10 cm.

formation-flying↗
NASA NTRS1999

Nonlinear Control of the Optical Delay Line Pathlength

This paper discusses the problem of designing a control system for an interferometer delay line which contains coarse-vernier loops. The vernier loop compensator has nonlinear dynamics and includes a local feedback path containing a deadzone.

nonlinear↗