1 ATLAS TileCal Production at UIUC Maggie Geppert, UIUC Dr. Steven Errede, project head July 9th, 2001

2 Overview Project Background Submodule Production Photomultiplier Tube (PMT) Testing What’s Next

3 Overview of ATLAS Located at Cern in Switzerland, ATLAS will be largest Particle Accelerator in the World Five Stories Tall Accelerates Protons to 7 trillion eV Scheduled to be Completed in 2005

4 Submodule Production Submodules are the framework of the detector. Hold the detector plates that glow in the presence of radiation from subatomic particles.

5 Submodule Production Seven easy steps to a submodule –Washing spacers and masters –Sanding and drying –Gluing –Welding –Measuring –Painting –Banding

6 Production Pictures Submodule assembly with glue machine Banding and wrapping

7 Photomultiplier Tubes (PMT’s) Signals from the detector array are amplified using PMT’s Currently testing 3,000 of the 10,000 to be used in ATLAS Run the tubes through a series of computer programs Right now finishing STEP 1 –DC light used during testing process

8 What do We Test? Drift –The % change in current over ~30 hrs –Not to be greater than +/- 2% Dark Current –Current through tubes when light isn’t on –must be < 2 nAmps at 800 Volts –must be < 4 nAmps at 900 Volts These are the 2 most important factors

9 Testing Problem –Systematic increase in the Drift of all tubes, including the reference tubes Solution –Look for external causes for the problem –Check testing setup for flaws in circuits or fiber-optic cable

10 First Look Looked at temperature, humidity, and other external factors –Little correlation

11 Next Steps Check hardware for internal problems –Currently running diagnostic tests –Then change the circuit setup in the light source After problem is fixed, run STEP 2 tests –Use pulsed light to test PMT’s Continue Submodule Production

12 Questions? Contact me Contact Dr. Errede –435 Loomis Lab UIUC ATLAS Website –