Session C14 - New Detectors and Instrumentation.
FOCUS session, Saturday morning, April 20
Ruidoso, Albuquerque Convention Center

[C14.001] Design of an Upgraded D0 Silicon Microstrip Tracker for Fermilab Run2b

The D0 collaboration has begun designing a new large scale silicon strip tracking system for the D0 detector for Run2b of the Fermilab Tevatron collider, which will deliver an integrated luminosity in excess of 15 fb-1 to the experiment. The current design of the detector will be presented with emphasis on those issues that drive the design, such as integrated radiation dose requirements, pattern recognition capability, alignment specifications, etc. The tracker will employ about 2200 single sided silicon sensors. Detector readout will utilize the SVX4 chip that is currently being designed for CDF and D0 Run 2b upgrades. The SVX4 will be built in radiation hard 0.25 micron technology, and operated in a mode compatible with the current readout electronics.

[C14.002] The D0 L2 Muon Trigger Algorithms

The D0 experiment operating at Fermilab utilizes three levels of triggers in its data acquisition. The Level 2 trigger has to decrease an input rate of 10KHz to 1 kHz within 100 \mus time budget. This paper will dicuss the muon Level 2 trigger, which uses the full muon front end information to do detailed reconstruction of muon candidates. This talk will describe the muon Level 2 trigger hardware and algorithms, and present results on its performance based on Monte Carlo and initial Run II data.

[C14.003] Reconstruction of electrons and photons in the D0 calorimeter

This study presents methods for determining positions of electron or photon-induced showers based on logarithmic weighting of the energies deposited in calorimeter cells. Monte Carlo samples of single electrons and photons are used to compare the resolution for Run I and Run II of the DO detector at Fermilab. We also present the current method used for correcting the position bias of electromagnetic objects in the D0 calorimeter that is based on use of Neural Networks, and indicate the precision that can be achieved for pointing showers to the interaction vertex using the information in the calorimeter and in the central preshower detector.

[C14.004] The Dzero central tracker

The DZero Collaboration has recently completed the upgrade of our detector in order to take advantage of the increase in luminosity of Fermilab's Tevatron Collider. Among the most novel portions of the upgrade are the scintillating fiber tracker and preshower detectors. They are made possible by using new solid state photodetectors called Visible Light Photon Counters (VLPC) that have a quantum efficiency of ~0.8. I will describe our detector, the motivations for its design and construction, and discuss some of the challenges met in its realization. I will also show some of the results we have obtained running it.

[C14.005] The Track-Finding Processor for the Level-1 Trigger of the CMS Endcap

We report on the development and test of a prototype track-finding processor for the Level-1 muon trigger of the Compact Muon Solenoid (CMS) experiment. The CMS experiment will study proton collisions at a center-of-mass energy of 14 TeV when the Large Hadron Collider begins operation in 2006. The Level-1 Trigger of CMS must reduce the 40 MHz beam crossing rate to approximately 100 kHz using custom electronic devices. The track-finding processor developed at the University of Florida reconstructs tracks in the endcap muon system of CMS, and reports the measured momentum of muon candidates to the Global Level-1 Trigger. The processor employs three-dimensional tracking algorithms to accommodate the non-axial magnetic field and high backgrounds in the CMS endcaps. A prototype processor was designed and built using programmable logic devices for flexibility, and successfully tested. The measured latency is only 400 ns for the decision logic. We also report on the plans for a pre-production prototype, as well as the overall physics capability of the endcap muon trigger.

[C14.006] Radiation-hardness studies of high OH^- content quartz fibres irradiated with 500 MeV electrons

We investigated darkening of nine high OH^- fibre types with 500 MeV electrons from the Linac Injector of LEP (LIL) at CERN. The transmission of Xe light was measured in situ in the 350-700 nm range. The induced attenuation at 450 nm is typically (1.5 2 + 0.15) dB/m for 100 Mrad absorbed dose. Two-parameter fits for darkening and recovery will be presented. (now at University of Maryland, College Park, USA)

[C14.007] Particle ID with dE/dx Measurement from CDF Central Outer Tracker (COT)

\par This is a first attempt to use dE/dx measured from the drift chamber COT at CDF for particle ID. \par Conversion electron tracks are used to calibrate and remove dependence on other factors apart from \beta\gamma, such as electronics gain, gas gain, track angles relative to beam direction and drift field direction. \par Correction formula obtained is applied on pure samples of protons, pions, and muons as well. A preliminary universal curve will be presented.

[C14.008] CMS HF CALORIMETRY PMT TESTS AND QUALITY CONTROL SYSTEM

The Forward Calorimeters of CMS detector will operate in a high radiation environment and play an important role on detecting the high energetic hadron jets coming out of candidate higgs events. These detectors will contain 2400 photomultiplier tubes (PMT) and these tubes has to be characterised and tested against the LHC operating conditions. We set up a PMT test station at the University of Iowa. We describe the test station and the quality control system and present the results from the measurements on PMTs.

[C14.009] Studies of Pixel Sensor Disigns for the CMS Experiment

The CMS experiment at LHC strongly relies on the precise tracking capability of the detector. With luminosities up to 10^34 cm^-2 s^-1 the super-imposition of typically 20 to 30 unrelated minimum bias events are foreseen within each bunch crossing, and thus a pixel detector as close as possible to the beam line is necessary for improving pattern recognition. The pixel arrays will be arranged in a barrel of two layers and four forward disks, two at each end, for high eta coverage. After six years of operation a total fluence up to 6x10^14 hadron/cm^2 will be integrated at a radius of 6 cm resulting in a full depletion voltage above 600V and a leakage current of few nA/pixel. An operational voltage of at least 300V without signs of breakdown is required to maintain good performance up to these fluences. Recent studies of prototype sensors, both oxygenated and not oxygenated, exposed to a fluence of 1x10^14, 6x10^14, and 1x10^15 neutron/cm^2 are presented. DC electrical characteristics before and after irradiation, at different temperatures and for different designs are compared and a design that fulfills the given requirements is chosen and described. A new optimized sensor design based on the experimental result is also presented. This design has already been submitted to the manufacturer for the final prototype phase.

[C14.010] Triggering on Muons at Level 1 in Run 2 of the DØExperiment

A new Level 1 muon trigger for the DØexperiment has been built to take advantage of new detectors and higher luminosity for Run 2 of the Fermilab Tevatron. We report on the current and planned triggering capabilities on muons at Level 1. Results on purity and efficiency of Level 1 muon triggers using data are presented. Level 1 muon triggers for t øverlinet production are discussed.

[C14.011] The D0 Silicon Track Trigger

The Silicon Track Trigger (STT) is a new component of the Level 2 trigger for the D0 experiment. Using the hit information from the Silicon Microstrip Tracker and the tracks found in the Central Fiber Tracker at the 1st trigger level, the STT will reconstruct tracks with better resolution than that available at level 1. The impact parameter will be measured with a resolution of 35 \mu m. This will allow D0 to select events with tracks from the decay of long lived particles. Track parameters (p_T, \phi and impact parameter) are provided for the level 2 trigger decision within 25 microseconds. The design and implementation of the STT will be discussed.

[C14.012] A Study of Topological Vertexing at CDF

Topological vertexing is a vertex finding technique developed at e\^+ e\^- experiments based on finding minima of a spatial `vertex probability' function. We adopt this approach to hadronic collisions at sqrt(s) = 2 TeV and study the efficiency and purity with a full Monte Carlo simulation of the CDF detector and on available CDF data.

[C14.013] High Intensity Tests of the NuMI Beam Monitoring Ionization Chambers

The NuMI facility at Fermilab will generate an intense beam of neutrinos directed toward Soudan, MN, 735 km away. Components of the planned beam monitoring system will be exposed to fluences of up to 8 x 10^9 charge particles / cm^2 and 6 x 10^10 neutrons / cm^2 in an 8.6 us beam spill. These fluences will be measured by an array of Helium ionization chambers. We tested a pair of chambers with 8 GeV protons at the Fermilab Booster accelerator, and with high intensity neutron sources at the Texas Experimental Nuclear Facility.

[C14.014] Prospects of the Multivariate b Quark Tagger for the Level 2 Trigger at D0

Looking for b quark jets, e.g. from the decay of a Higgs boson, at a high rate p p-bar collider requires a large suppression factor of jets produced by light quarks. We will present the layout of the future implementation of D0's level 2 b quark tagger. In its current design it has to reject about 90% of the incoming events with an available processing time of about 10 ms event using relatively coarse level 2 data from D0 Run 2 detector. Combining several tagging parameters in a multivariate analysis method (support vector machine) has shown to increase the suppression power. We will show which parameters are used to identify b quark jets, how these parameters are combined using a support vector machine and what the performance of the tagger and its effect on D0's b quark event rate is expected to be.

[C14.015] MINOS Beamline Muon Monitoring

The MINOS experiment will generate a beam of neutrinos from tertiary proton interactions at Fermilab and direct them toward a detector 735 km away in the Soudan Mine. Reliability of the beamline components is paramount and although a near detector exists, a change in the beamline configuration is observed using only neutrino interactions over a period of days. We present an instrumentation system using tertiary muons which can provide an instant feedback system for monitoring the quality of the beamline. Radiation-hard ion chambers have been designed and tested at the Brookhaven ATF facility. Results of the tests will be presented.

Part C of program listing