Linear Collider Detector TRACKING R & D


This page:

Introd.

MainTrker:

AxialWire

TPC

Si

Int/FwdTrkg

Detector R&D Links

Other

News


Links to international meetings:


Tracking efforts in this webpage:

Simulations

Axial Wire

TPC

Si

Related

Int/Fwd Trkg


Aim of this page is to link the different activities on tracking in the framework of the World-Wide Studies of Physics and Detectors for Future Linear e+e- Colliders.

An overall description of the R&D program of the World-Wide Study can be found in the Linear Collider Detector R&D paper available as postscript or PDF version. For other activities in the International Linear Collider Detector R&D see this WWW page

INTRODUCTION

All tracking-system designs under consideration include a pixelated vertex detector that closely surrounds the interaction point for accurate measurement of charged particle impact parameters. Accurate momentum measurement is provided by either a large-volume gas drift chamber (axial/stereo wires or time projection chamber) or additional silicon tracking layers (silicon drift detector or microstrips) immersed in axial magnetic fields of magnitude > 3T. Designs also include a dedicated system of forward-tracking silicon disks at low angles. For the gas chamber barrel trackers, additional special silicon, straw chamber or scintillating fiber layers are also under consideration for improving pattern recognition, momentum resolution, or timing precision. In the following R&D for each of the tracking technologies is discussed and relevant websites for tracking and other subdectors are collected below.

Main Tracker

Excellent track reconstruction efficiency and momentum resolution are desirable over a large solid angle at the linear collider. Two distinct approaches are under consideration for the barrel tracking system, a large-volume gas drift chamber ( axial/stereo wire or time projection) with continuous tracking involving many coarse (~ 100 mu) measurements or a silicon tracker with a few precise (~ 10 mu) measurements per track. Aside from the technical tradeoffs in designing within one of these approaches, there are global tradeoffs among them, pertaining to pattern recognition, robustness against background, material budget affecting multiple scattering, bunch discrimination via timing, and interface to calorimetry. Collaborative simulation work is ongoing in the North American community to address these global issues.
The Asian detector design includes a large-volume drift chamber with axial and small-angle stereo wires. A long-term R&D program is well under way to address the following issues:
Some general arguments for a TPC as main tracker are listed to illucidate the R&D issues:
The European detector design includes a large-volume time projection chamber (radius 1.7, half-length ca. 2.5 m), while the North American version has a larger radius (2 m). A collaboration of European and North American institutes have begun a comprehensive R&D program to address the following issues:
A proposed a superlayer of straw drift chambers behind the endcap of the European TPC, mainly to improve momentum resolution at lower angles. A silicon version is also being considered (see next paragraph). Technical R&D issues include spatial resolution, material thickness, timing for bunch tagging and calorimeter splashback.
Being investigated are large silicon annular planes behind the endcap of the European TPC and a large barrel layer beyond the outer radius of the TPC, in both cases between the tracking chamber and the electromagnetic calorimeter. The endcap tracking layer significantly improves momentum resolution at forward angles. The outer barrel layer offers a calibration point for the gas chamber, a function which also may be fulfilled by the Ecal. Given the sizes of these auxiliary tracking layers, lowering cost of manufacture will be important R&D goals.
The North American study groups have considered in their simulations both a TPC and a 5-layer silicon barrel tracker of maximum outer radius 1.25 m and maximum half-length 1.67 m. Two different silicon technologies are under consideration: silicon drift detector and silicon microstrips, discussed below. A silicon drift detector design involves the following issues for an R&D program: Simulations for a silicon microstrip detector design lead to the following an R&D issues:
Both of the European and North American TPC designs also include a barrel silicon layer at a radius just short of the inner radius of the TPC. The extra layer provides improved momentum resolution and, it is hoped, provides improved pattern recognition to match tracks across the gap between the vertex detector and the gas chamber. The R&D being proposed by several groups for other silicon layers is expected to be relevant to this intermediate layer also.
Most of the tracking system designs include a set of silicon annuli providing angular coverage to cos(theta)~.99. In the European design, the first three (of seven) layers from the interaction point are active pixel sensors; the rest are silicon microstrips, as are all of the annuli in the North American designs.
In America the timing advantages of a superlayer of scintillating fibers in place or adjacent to the intermediate barrel silicon layer in the North American TPC option are being studied. R&D issues include timing precision and material thickness.
Simulations and R&D have begun on a dedicated "pair monitor", based on active pixel sensor devices at very low angles near the final beam quadrupoles. The monitor would track the passage of Bethe-Heitler pairs, as a real-time beam diagnostic and as an independent measure of luminosity.

Links to the LC Detector R&D Projects


This is a preliminary list of links and is still incomplete. Suggestions for further links to be included should please be sent to Ron Settles.


Vertex Detector

Main Tracker

Intermediate/Forward Tracking

Calorimeter

Muon Detector

Particle ID

Beamline Instrumentation

Data Acquisition

Test Beams

Gamma-Gamma Detector


Other links of general interest

To reiterate, for world R&D related to the LC detector...


News

On January 2, 2003, this Tracking R&D page went public. A preliminary list of links can be found bove. The aim is to get a complete list of Tracking R&D projects. Please submit links for your specific Tracking R&D page to Ron Settles.


Ron Settles
Last modified: Thursday 2 January 2003 19h CEST