Status of the D0 fiber tracker and preshower detectors

Abstract

In this report we focus on the performance of the D0 central fiber tracker and preshower detectors during the high luminosity pp 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.Key words: D0 scintillating fiber tracker, preshower detectors, visible light photon counters, track trigger, D0 AFEII-t electronics PACS: 07.77. Ka, 29.40.Mc, 85.60.Gz The Tevatron and the D0 DetectorThe Tevatron located at Fermi National Accelerator Laboratory is a superconducting synchrotron capable of accelerating proton (p) and anti-proton (p) beams in opposite directions to energies of 980 GeV. Particles in the beams are grouped in 36 spatially separated bunches which are brought into the head-on collisions at the center of the D0 detector [1,2] at 396 ns intervals.As a typical collider detector, the D0 detector has a tracking system, electromagnetic and hadronic calorimeters, and muon chambers to measure the energy, momentum, and charge of particles produced in the collisions. The central tracking system consists of a silicon microstrip tracker (SMT) and a central fiber tracker (CFT) both located within a 2 T superconducting solenoidal magnet, with designs optimized for tracking and vertexing at pseudorapidities |η| < 3 and |η| < 2.0 respectively. The central and forward preshower detectors (CPS and FPS) positioned just outside of the superconducting coil are used to improve the measurement of energies of electron and photon showers detected by the D0 calorimeter system. A liquid-argon and uranium calorimeter has a central section (CC) covering pseudorapidities |η| up to ≈ 1.1, and two end calorimeters (EC) that extend coverage to |η| ≈ 4.2, with all three housed in separate cryostats. A muon system, at |η| < 3, consists of layers of tracking detectors and scintillation trigger counters surrounding 1.8 T toroid magnets [3].In Run IIb, with initial instantaneous luminosities reaching over 3 × 10 32 cm −2 s −1 and more than 5 pp interactions per bunch crossing, the D0 detector faces stringent challenges. In the following sections, we will discuss the CFT and PS detectors, and the central track trigger (CTT) hardware, as well as upgrades performed on the readout electronics aimed to improve identification of charged particles. The Central Fiber TrackerA schematic cross sectional view of one quarter of the CFT is shown in Fig. 1. It consists of eight thin coaxial carbon-fiber cylinders, each supporting two layers of overlapping scintillating fibers (doublets), each fiber having a 0.835 mm diameter. Tracking in the CFT is done by detecting the scintillation light produced when ionizing particles traverse the fibers. A small fraction of generated light is trappe...

Measurement of the $W$ Boson Mass in Proton-Antiproton Collisions at a Center of Mass Energy of 1.96 TeV

“…Although the electronics have since been replaced this analysis does not utilize any readout from either of the pre-shower detectors. Reference [20] focuses on the performance of the pre-shower and fiber tracker detectors for RunIIb.…”

Di-J/Ψ Studies, Level 3 Tracking and the D0 Run IIb Upgrade

“…The triggering system also underwent substantial upgrades during the shutdown period, in particular to Level 1 [50]. allows for the L1CTT to make better use of the granularity of the CFT axial fibres and hence reduce the fake rate (and thus the trigger rate) [52].…”