Central Fiber Tracker Research Articles

Status of the D0 fiber tracker and preshower detectors

In this report we focus on the performance of the D0 central fiber tracker and preshower detectors during the high luminosity p p ¯ collisions at s = 1.96 GeV delivered by the Tevatron collider at Fermilab (Run IIb). Both fiber tracker and preshower detectors utilize a similar readout system based on high quantum efficiency solid state photo-detectors capable of converting light into electrical signals. We also give a brief description of the D0 detector and the central track trigger, and conclude with a summary on the central tracker performance.

Upgrade and operation of the DØ central track trigger

The DØ experiment at the Fermilab p p ¯ Tevatron collider (Batavia, IL, USA) has undergone significant upgrades in anticipation of high luminosity running conditions. As part of the upgrade, the capabilities of the Central Track Trigger (CTT) to make trigger decisions based on hit patterns in the Central Fiber Tracker (CFT) have been much improved. We report on the implementation, commissioning and operation of the upgraded CTT system.

The upgraded DØ detector

The DØ experiment enjoyed a very successful data-collection run at the Fermilab Tevatron collider between 1992 and 1996. Since then, the detector has been upgraded to take advantage of improvements to the Tevatron and to enhance its physics capabilities. We describe the new elements of the detector, including the silicon microstrip tracker, central fiber tracker, solenoidal magnet, preshower detectors, forward muon detector, and forward proton detector. The uranium/liquid-argon calorimeters and central muon detector, remaining from Run I, are discussed briefly. We also present the associated electronics, triggering, and data acquisition systems, along with the design and implementation of software specific to DØ.

Alignment of the central DØ detector

The alignment procedure of the Silicon Microstrip Tracker (SMT) and the Central Fiber Tracker (CFT) is described. Alignment uncertainties and resulting systematic errors in physics analyses are addressed.

The central track trigger of the DO experiment

The general purpose DO collider detector, located at Fermi National Accelerator Laboratory, is operated in the high luminosity (L=2/spl times/10/sup 32/ cm/sup -2//spl middot/s/sup -1/) and high-collision-rate environment (396 ns between beam crossings) of the upgraded Tevatron proton anti-proton accelerator. DO uses a three-tiered trigger system to select events for offline storage and analysis. This paper describes the architecture and performance of the DO central track trigger (CTT) system based on the new central fiber tracker, central preshower and forward preshower detectors, with emphasis on the interface to and integration with the second tier L2 Trigger system.

First results from the central tracking trigger of the DO experiment

An overview of the DO Central Track Trigger (CTT) for the Tevatron Run 2 program is presented. This newly commissioned system uses information from the DO Central Fiber Tracker and Preshower Detectors to generate trigger information for the first level of the three-tiered DO Trigger. The system delivers tracking detector trigger decisions every 132 ns, based on input data flowing at a rate of 475 Gbit per second. Initial results indicate excellent performance of the CTT. First studies of efficiency and trigger performance of the CTT are presented.

The DO central track trigger

An overview of the system architecture and algorithms used for the DO Central Track Trigger (CTT) in the Run 2 of the Fermilab Tevatron Proton-Antiproton Collider is presented. This system uses information from the newly commissioned Central Fiber Tracker and Preshower Detectors to generate Level 1 trigger decisions. It also generates lists of seed tracks and preshower clusters that are sent to the Level 1 Muon Trigger, L2 Silicon Track Trigger, and Central and Forward Preshower Level 2 preprocessors. The system consists of modular boards which utilize field-programmable gate arrays (FPGAs) to implement trigger algorithms. The system delivers trigger decisions every 132 ns, based on input data flowing at a maximum sustained rate of 475 gigabits per second. The first results of trigger efficiency studies are presented.

Real-time data reorganizer for the D0 central fiber tracker trigger system at Fermilab

A custom digital data mixer system has been designed to reorganize, in real time, the data produced by the Fermilab D0 Scintillating Fiber Detector. The data is used for the Level 1 and Level 2 trigger generation. The mixer system receives the data from the front-end digitization electronics over 320 Low Voltage Differential Signaling (LVDS) links running at 371 MHz. The input data is de-serialized down to 53 MHz by the LVDS receivers, clock/frame re-synchronized and multiplexed in Field Programmable Gate Arrays (FPGAs). The data is then reserialized at 371 MHz by LVDS transmitters over 320 LVDS output links and sent to the electronics responsible for Level 1 and Level 2 trigger decisions. The Mixer System processes 311 Gigabits per second of data with an input to output delay of 200 nanoseconds.

THE $D\emptyset$ LEVEL 1 TRIGGER SYSTEM

We describe the Level 1 muon trigger system for Run II of the [Formula: see text] colliding beam experiment at the Fermilab Tevatron. The muon trigger logic makes use of tracks from the central fiber tracker and hits from muon detector elements which include both scintillator and drift tube arrays. Details of the FPGA trigger logic and trigger simulation results are given. Extensive use is made of Gbit/s serial links in order to transmit data to the Level 1 muon trigger system. Results on error rates from these Gbit/s serial links using up to 200 feet of coaxial cable are presented.

A silicon track trigger for the DØ experiment

The design of a processor to trigger on long-lived particles (e.g. b-quarks) for the DØ experiment at the Fermilab Tevatron is presented. This device reconstructs the trajectory of the charged particles in the DØ tracking system, which consists of a central fiber tracker and a silicon microstrip tracker. The r- φ impact parameter resolution of the fitted tracks is about 40 μm. This enables the identification of the long-lived b-quarks produced in the decays of various particles, e.g. the top quarks, Higgs Boson, techni-particles and other exotic particles produced in p p ̄ collisions at the Tevatron. In this report we describe the design of the architecture and algorithms for the Silicon Track Trigger.

Calibration system for the central fiber tracker for the DO upgrade

We are developing a calibration system for the Central Fiber Tracker (CFT) for the DO Upgrade to monitor the optical integrity, channel gain, and gain stability for the 76000 fiber channels with VLPC readout which comprise the system. Excitation is by blue Light Emitting Diodes (LEDs), with light distributed to the CFT fiber ribbons via luminous fiber panels. System design and performance will be presented.

The level 1 muon trigger for Run 2 of DO

We describe the Level 1 muon trigger system for Run 2 of the DO colliding beam experiment at the Fermilab Tevatron. The Level 1 muon trigger rate for high P/sub T/ single muons and low P/sub T/ dimuons is designed to be less than 25% of the 10 kHz total Level 1 trigger bandwidth at a peak luminosity of 2/spl times/10/sup 32//cm/sup 2//s. The muon trigger logic makes use of tracks from the central fiber tracker and hits from all muon detector elements. Details of event synchronization, event buffering, and FPGA trigger logic are given. Results on Gbit/s serial link transmission of data over coaxial cable are shown. Simulation of the muon trigger system is discussed.

A fast, first level, R/spl phi/ hardware trigger for the D0 central fiber tracker using field programmable gate arrays

An R/spl phi/ trigger was developed using the eight doublet layers of axial fibers in the new Central Fiber Tracker for the DO Upgrade Detector at Fermilab. This trigger must be formed in less than 500 nsec and distributed to other parts of the detector for a level 1 trigger decision. The high speed is achieved by using massively parallel AND/OR logic realized in state-of-the-art field programmable gate arrays, FPGAs. The programmability of the FPGAs allows corrections to the track roads for the as-built detector and for dynamically changing the transverse momentum threshold. To reduce the number of fake tracks at high luminosity, the narrowest possible roads must be used which pushes the total number of roads into the thousands. Monte Carlo simulations of the track trigger were run to develop the trigger algorithms and a vendor specific commercially available simulator was used to develop and test the FPGA programming.