BTeV Pixel DetectorBTeV Pixel Detector

Laurie RamrothLaurie RamrothFermi National LaboratoryFermi National Laboratory

Under the direction of:Under the direction of:Jim FastJim Fast

Pixel DetectorPixel Detector

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

Problem #1:Problem #1:

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

Joints In QuestionJoints In Question

The 2 joints in question are located above The 2 joints in question are located above and below the High Density Interconnector and below the High Density Interconnector (HDI)(HDI)

Cross Sectional View of Pixel Cross Sectional View of Pixel Module and Support StructureModule and Support Structure

ConstraintsConstraints

Parts need to survive a temperature drop Parts need to survive a temperature drop to -196C (the temperature of the liquid to -196C (the temperature of the liquid nitrogen)nitrogen)

Adhesive must be thermally conductive in Adhesive must be thermally conductive in order for heat to be transferred to order for heat to be transferred to substrate.substrate.

Plan of attack:Plan of attack:

Research adhesive properties at low Research adhesive properties at low temperaturestemperatures

Assemble prototypes and test them for Assemble prototypes and test them for strain at -20C (operating temperature) and strain at -20C (operating temperature) and for failure at -196C (constraint)for failure at -196C (constraint)

Problem #2:Problem #2:

How fast is heat produced by the readout How fast is heat produced by the readout chip being expelled from the pixel modules chip being expelled from the pixel modules by thermal conduction through the by thermal conduction through the pyrolytic graphite and the carbon fiber?pyrolytic graphite and the carbon fiber?

Where is all the heat going?Where is all the heat going?

The detector is in a vacuum. Thus, the The detector is in a vacuum. Thus, the heat being produced has no where else to heat being produced has no where else to go but through the detector and into a heat go but through the detector and into a heat sinksink

Half Detector AssemblyHalf Detector Assembly

ConstraintsConstraints

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

Plan of attack:Plan of attack:

Measure thermal conductivity of pyrolitic Measure thermal conductivity of pyrolitic graphite and carbon fiber.graphite and carbon fiber.