Straw Tubes and Hall D Zebulun Krahn Carnegie

Straw Tubes and Hall D Zebulun Krahn Carnegie Mellon University Advisor: Curtis Meyer Technician: Gary Wilkin Glue. X Collaboration Meeting December 11 -13, 2003

Outline of the Talk • Work Done to Date § Gas simulations, endplate production, etc • Current Work § Straws, feed-through system, glue tests, stringing • Future Plans § Electronics, DAQ, prototype testing…

Built Gas Mixing System Matches JLAB equipment Can mix up to three gases Completed June ‘ 02

Garfield Gas Simulations Lorentz Angle vs. Drift Time Note 62 -Completed Nov. ‘ 02

Studies of BNL Chamber Studied performance of chamber with cosmics and Ru 106 • Studied coincidence between tubes • Studied position dependence • Dissection to analyze construction methods Completed Dec. ’ 02 Note 54 Note: Very Leaky!

Prototype Endplates ¼ endplates machined + checked at JLAB Straight and Stereo layers 2 -3 man months set-up and machining Completed June ‘ 03 Note 61 Final Accomplishment: Successfully closed out a JLAB R+D account

Current Work Goal: Build a prototype full scale ¼ chamber at CMU Since May of ‘ 03

Issues with Straw Tubes Straw Tube vendors • Vendors differ widely in price and service • On preliminary order, as many as ¾ of the tubes, not usable • Shipping of Tubes How do you cut a 4 mil walled straw tube? 12, 000 RPM with a 10 mil blade

Issues with Straw Tube Chambers They leak! • Look for design that allows for gas-tight system • Determine methods of containing leaks that do exist • System design and product testing § Epoxy testing

Epoxy Testing Two important criteria: • Gas-tight seal • Electrical conductivity Used a known non-conductive epoxy as baseline: 3 M Scotch-Weld 2216 Two candidates, to date might use both §Resin-Tech TIGA 920 -H §Tra-Con 2907 Held 2. 5 PSI for several weeks Fill Valve Pressure Gauges

Feed-Through System Two main components: • Donuts § Inserted in end of straw tube §Hole and V-notch allow injection of epoxy Tube

Feed-Through System II • Feed-Through § Inserted through endplate and captures donut § Chamfer allows space for glue

Gas Flow System Towards Gas-Tight goal • Learned a lot from BNL chamber – minimize leaks • Plenum Design Gas Seal § Plexiglas plenum covers § Stand-offs § Electronics? Gas Seal

Stringing Method Axle system for stringing • Whole chamber rotates on axis § Hook + Swivel § Ball Joint + Base Plate • Tension cables prevent bowing Note: We are building stringing apparatus for actual full size chamber!

Sliding Collars Allow for capture of inner radius of endplates Lower collar bolted to axle for strength Upper collar allowed to slide capture, set screwed in

Hook + Swivel Joint Steel plug inserted into aluminum axle • Allows for use of crane/winch § Mobility • Allows for rotation of chamber This steel plug will also be the anchor point for tension cable/rods

Ball Joint + Base Plate Steel Plug inserted into aluminum axle • Captures the bottom of axle • Allows for rotation and more! § Stereo layers Base Plate will bolt to floor

The Axle Specifications: • Length : 10 feet • Radius: 5. 5 inch OD • Wall Thickness: ½ inch • Weight: 93 lbs • Maximal Deflection for 600 lb chamber: 1. 6 mm Limiting factor: ability to machine the axle

Future Work 1. Actual Manufacture of required pieces • Donuts, Feed-Throughs, sliding collars, ~50 tube prototype 2. Electronics: • PC-Boards and Pre-Amps 3. Setting up DAQ 4. Upon completion of prototype, testing will be needed

Conclusion • Work Done to Date § Gas simulations, endplate production, etc • Current Work § Straws, feed-through system, glue tests, stringing • Future Plans § Electronics, DAQ, prototype testing…