1. BTeV Pixel Detector Laurie Ramroth Fermi National Laboratory Under the direction of: Jim Fast

2. Pixel Detector The purpose of the pixel detector is to measure the momentum of the b quarks before decay at collision of the proton antiproton beams.

3. Problem #1: Bonding two different materials at room temperature and then operating them at ~ -20C. What are the best adhesive choices for the joints in question?

4. Joints In Question The 2 joints in question are located above and below the High Density Interconnector (HDI)

5. Cross Sectional View of Pixel Module and Support Structure

6. Constraints Parts need to survive a temperature drop to -196C (the temperature of the liquid nitrogen) Adhesive must be thermally conductive in order for heat to be transferred to substrate.

7. Plan of attack: Research adhesive properties at low temperatures Assemble prototypes and test them for strain at -20C (operating temperature) and for failure at -196C (constraint)

8. Problem #2: How fast is heat produced by the readout chip being expelled from the pixel modules by thermal conduction through the pyrolytic graphite and the carbon fiber?

9. Where is all the heat going? The detector is in a vacuum. Thus, the heat being produced has no where else to go but through the detector and into a heat sink

10. Half Detector Assembly

11. Constraints Heat produced by the readout chip needs to be expelled to the liquid nitrogen (heat sink) via the substrate so that the system is maintained at ~-20C

12. Plan of attack: Measure thermal conductivity of pyrolitic graphite and carbon fiber.