The CDF intermediate silicon layers detector

The Intermediate Silicon Layers detector (ISL) was proposed as a part of the upgraded CDF detector at the RUN-II of the Tevatron pp Collider at Fermilab, scheduled to start in year 2000. The ISL is a large-radius (20–30 cm) silicon tracker with a total active area of about 3.5 m2. Locatedin the region between the Silicon Vertex Detector (SVX II) andthe Central Outer Tracker, the ISL will allow tracking in the forwardregion andsignificantly improve it in the central area. Together with the SVX II the ISL forms a standalone, 3D silicon tracker. The challenge is to build a low-cost device which provides precise 3D tracking in a = 2 m long area with a minimal amount of material for the supporting structure. The conceptual design and the status of the project are reviewed.