ATLAS Tile Hadron Calorimeter at UIUC Dave Petersen

ATLAS Tile Hadron Calorimeter at UIUC Dave Petersen, North Park University Working under HEPG Prof. Steve Errede

What, Who and Where? • A Toroidal Large Hadron Collider Apparatus (ATLAS) Detector • Over 30 countries involved, from Armenia to the United States (over 30 U. S. institutions are participating) • To be built at CERN, near Geneva, Switzerland

What is the LHC? • A proton will be colliding with another proton • Will achieve energy of 14 Te. V, most energetic collider in the world

ATLAS: A Five Story Detector • Red line is the beam pipe • Pink is the tracking detector • Gray is the Solenoid Magnet • Yellow is the Electromagnetic Calorimeter • Green is the Hadron Calorimeter • Gray tubes are muon torodial magnet • Blue is the muon detector

What is UIUC doing for ATLAS? • UIUC is one of 5 institutions working on the Scintillating Tile Hadron Calorimeter – Produce ~200 full-size Submodules – Test ~3, 000 Photomultiplier Tubes

What is a Module? • 64 Full Modules required for Tile. Cal • Each Module is composed of 8 full-size submodules, one half-size and one quartersize.

How does the Tile. Cal work? • Steel absorbers separated by tiles of scintillating plastic • When the Hadronic shower, hits the scintillating tiles, they emit light in an amount proportional to the incident energy • Fiberoptics connected to the tiles carry the light to PMTs

Production of Submodules • UIUC wants to finish production by May of 2002 • Currently have 49 complete • Looking to improve efficiency of operations -one of the biggest problems is the cleaning of the plates that has to be done by hand • Over 10 miles of steel required for 192 submodules

Quality Steel from the Czechs • Notice the grease on these plates • Every single plate must be washed by hand • There are 192 spacers plates and 32 master plates per submodule that must be washed

Stamped, Not Laser-Cut • Spacers are. 004 in. thinner than design qualifications • The Tile. Cal design calls for submodules must be within. 002 in. • So we place. 004 in. stickers on each individual spacer before we glue

Gluing • Takes a little over 2 hours to stack and glue one submodule • Use glue machine which requires over 8, 000 lines of code • Prof. Errede desires to break the 2 hour barrier (his own version of the 4 minute mile)

Quality Control • After welding, various measurements must be taken to ensure that each submodule meets the design requirements • We must also check each individual slot for the tiles to make sure the tiles will fit

Analysis of Quality Control • Here is a 3 D graphical view of the average submodule heights broken up by points

Painting - In order to rustproof • Toxic paint from the Czech Republic is used to “rustproof” the submodules • Takes over 3 days to dry • Excess paint must be ground off

Ready to Ship • These submodules are ready to go to Argonne, where they will be assembled into a full module

PMT Testing • UIUC will perform test on the PMT’s that will measure – PMT Performance – PMT Rate Dependence – PMT Drift/Stability/Aging Studies • UIUC will receive testing boxes shortly

Test Each PMT Twice • Using Lab. View, UIUC will test each Hamamatsu R-7787 PMT twice, once in the Dark box and once in the Light box – Test 1 will use DC Light • Test 20 PMTs per 2 days – Test 2 will use Pulsed Light • Test 20 PMTs per day

What will ATLAS show us? • The measurements taken using ATLAS will hopefully help explain these theories – Higgs Particle and Field – Grand Unified Theory

Higgs Particle and Field • Higgs field is almost indistinguishable from empty space • All of space is filled with this field, and that by interacting with this field, particles acquire their masses. • Particles that interact strongly with the Higgs field are heavy, while those that interact weakly are light.

Grand Unified Theory • Physicists hope to unify the weak, strong, and electromagnetic interactions

Thanks To • Dr. Steven Errede • Dave Forshier • And Fred Cogswell, who when I invited him to attend this talk gave me this response