1. The Intermediate Silicon Layers detector OUTLINE ISL inside CDFII Why the ISL? Conceptual Design Ladders and Spaceframe Rasnik Online Alignment System (6“ Sensor technology will be shown in the next talk) DPG Frühjahrstagung Heidelberg, 15. - 19.März 99 Frank Hartmann Institut für Experimentelle Kernphysik Der Silizium Zwischenlagen-Detektor für Die Erweiterung des CDF Detektors am Tevatron

2. THE CDF II DETECTOR &THE ISL The ISL

3. SVXII (Silicon Vertex) + Layer00 z3 barrels 5 layers z12 wedges zRadii 2.45 - 10.6 cm zlayer 0,1,3 90 o zlayer 2,4 + 1.2 o Layer00 Beyond baseline Radius 1.6 cm

4. Why the ISL? High momentum resolution combined with COT |  |<1 Fine granularity helps to resolve ambiguities in dense track environments (e.g. in stiff jets t t ) ISL & SVXII combined provide a precision standalone silicon tracking system with up to 7 axial and 7 stereo measurements Adds forward tracking (1<|  |<2) p T resolution: impact parameter: Add. Spacepoint --- R=10.6 and 40 cm COT ISL SVXII Distribution of primary vertices (z)

5. ISL Conceptual Design Considerations Simple design, limited R&D Take advantage of SVXII R&D use the same electronics and DAQ. Take advantage of the large radial position of the layers less radiation ==> S/N can be lower ==> more surface area of Silicon per readout channel. hit density is much lower ==> larger strip pitch and relaxed mechanical tolerances. Material: 0.5% rad. length (central region) 1% rad. length (forward region) 1% rad. Length (hybrids, endcaps, cooling) ?

6. ISL System Components ~ 888 large area, double sided silicon microstrip sensors. 303 104 total channels 512 strips on each side with a pitch of 112  m Strips on one side have a stereo angle of 1.2 degrees Sensors grouped into readout triplets called ladders Each ladder has double-sided AlN readout hybrid. Sensors and hybrid are supported by a carbon fiber shell. 296 Ladders are paired to form 148 modules. Modules installed on Carbon fiber supports to form barrels. ISL Barrels are assembled into a space frame Operational temperature 10-15 0 C ; water cooling (chilled water) ISL 3 * 90 0 layers 4 * 1.2 0 layers

7. Mechanical design of the spaceframe 195,2 cm RINGS: Carbon fiber RODS: Hollow carbon fiber No direct connection to carbon fiber ladders, only to hybrids FEA: gravitational sag 20mu Weight 7 kg Every second ladder displayed Radii: ~20cm & ~30cm

8. Spaceframe: Al Prototype Forward Barrel mechanical ladder dummies Final carbon fiber rods (hollow) Spaceframe Assembly Expected final precision 50mu overall

9. ISL Ladder Design and Mounting (1) max rigidity & min material due to carbon fiber design Full rigidity reached with sensor gluing Geometry allows easy microbonding Wedge shape to max rigidity

10. ISL Ladder Design and Mounting (2) Position precision dependent on silicon only, alignment hole on hybrid Hybrid tower (rotating) with precision pin 3 silicon sensor tower with teflon (x,y,rotating) Al support for the carbon ladder High precision bearings Ladder will be placed on Al support beneath the teflon planes. Silicon sensors will be positioned in respect to the hybrid‘ precision hole. Glue will be put on carbon fiber ladder. Support and ladder will be elevated to connect ladder and silicons. z-stages

11. Rasnik: The Online Alignment System (1) CCD image of the mask shields Coded Masks - Lenses - CCDs Movement of one part induces a shift in the mask-image in the CCD. Online Alignment check Submicron range IR

12. Rasnik: The Online Alignment System (2) Cheap alignment system Simply controlled and readout with one PC

13. Conclusion The ISL is a relatively young project (starting OCT. 96) ISL/SVXII allows standalone tracking Most Spaceframe parts are ready and partially mounted Mounting fixtures are ready MICRON as well as HAMAMATSU are delivering silicon sensors Hybrids are in production First prototype ladder has been built and is working Preproduction will start next month Engineering RUN spring 2000; DATA TAKING fall 2000