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

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

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

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

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

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

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

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

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

Epoxy Testing Two important criteria: Gas-tight seal Electrical conductivity Used a known non-conductive epoxy as baseline: 3M Scotch-Weld 2216 Two candidates, to date might use both  Resin-Tech TIGA 920-H  Tra-Con 2907 Pressure Gauges Fill Valve Held 2.5 PSI for several weeks

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

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

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

Stringing Method Axle system for stringing Tension cables prevent bowing Whole chamber rotates on axis  Hook + Swivel  Ball Joint + Base Plate 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 Allows for rotation of chamber Allows for use of crane/winch Steel plug inserted into aluminum axle This steel plug will also be the anchor point for tension cable/rods  Mobility

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 Length :10 feet Radius: 5.5 inch OD Wall Thickness: ½ inch Maximal Deflection for 600lb chamber: 1.6 mm Weight: 93 lbs Specifications: Limiting factor: ability to machine the axle

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

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