340 likes | 460 Views
The UIUC ATLAS TileCal Project. Project Head - Dr. Steven Errede. Niall Nethercote UIUC High Energy Physics Summer 1998. Contents. Background on Experimental Particle Physics The World-Wide ATLAS Project The UIUC ATLAS TileCal Project Sub-Module Fabrication
E N D
The UIUC ATLAS TileCal Project Project Head - Dr. Steven Errede Niall Nethercote UIUC High Energy Physics Summer 1998
Contents • Background on Experimental Particle Physics • The World-Wide ATLAS Project • The UIUC ATLAS TileCal Project • Sub-Module Fabrication • Photomultiplier Tube (PMT) Testing • Our Web Site
Topic 1 Experimental Particle Physics
Particle Accelerating Facility • Accelerating Ring • Detector
How is a Particle Detected? • Accelerate some matter (e.g. the quarks of protons) • Collide the quarks (and get a mess of gluons) • Interesting particles may form (e.g. top quark) • Detect the residual particles (e.g. w/ a PMT)
Topic 2 The World-Wide ATLAS Project
CERN • CERN is the European Laboratory for Particle Physics • CERN is located in both France and Switzerland • It is very near Geneva, Switzerland
The LHC Project • Large Hadron Collider (LHC) Ring • Compact Muon Solenoid (CMS) Detector • AToroidal LHC Apparatus (ATLAS) Detector • CERN is upgrading in three major ways
The ATLAS Project • 144 institutes world-wide are collaborating on the ATLAS project • ATLAS is 5 stories tall! • ATLAS will detect proton-proton collisions • Its center of mass energy is 14 TeV! • ATLAS will start taking data in 2005
Topic 3 The UIUC ATLAS TileCal Project
UIUC and ATLAS • What part of ATLAS does the UIUC group work with? • The Scintillating Tile Hadron Calorimeter (pictured green) • Sub-modules are made of alternating layers of steel and scintillating tile (shown in next slide) • Groups of sub-modules are modules • Groups of modules form the Hadron Calorimeter
What Does the UIUC Group Do? • The UIUC ATLAS project is two-folded • Sub-Module Fabrication • Photomultiplier Tube (PMT) Testing
Hadron Detection • How are hadrons detected with sub-modules and PMTs? • Hadron flies through scintillating tile and photons are released • Fiber optics route some photons to a PMT • Photons hit PMT and convert to photoelectrons (via photoelectric effect) • Electrons are multiplied inside PMT and a detectable signal results
Sub-Module Fabrication • UIUC’s sub-module assignment • Glue machine • Prototype sub-module production
The Sub-Module Assignment • UIUC is responsible for producing 200 extended barrel sub-modules • In the extended barrel 9 sub-modules make up a module (and also recall that there are 64 modules circling around the beam axis) • So when you do the math it turns out that we are making about 1/3 of an extended barrel
Glue Machine • The glue machine will be used to apply very precise amounts of glue to the sub-modules • It is currently being constructed and will be ready for early 1999 when we begin to make some more sub-modules • Dr. Errede and Fred Cogswell (our machinist) have put the most work into the glue machine
Sub-Module Prototype Production • During the Winter of 1996-1997 we constructed some prototype sub-modules
Photomultiplier Tube (PMT) Testing • General • UIUC’s PMT testing assignment • Our PMT testing setup • The work that we did this summer • Dark Box modification • PMT Aging experiments
The PMT Testing Assignment • When ATLAS begins data taking it will be using approximately 10,000 PMTs! • Here at UIUC it is our job to test over 3,000 of those PMTs (i.e. about 1/3 of ATLAS’s PMTs)
Our Laboratory • Here is a shot of Dr. Errede’s Laboratory • Note the crates and the dark box
Our Dark Box • Here the crates are on the left, the dark box is on the right, and that’s Jori walking into the lab • The mess of wires that run in and out of the dark box • The dry nitrogen system can also be seen
Inside the Dark Box • This is our PMT testing layout that is housed in the dark box
Dark Box Modification • Our group needs to prepare for the testing of the over 3,000 PMTs • The biggest task is modifying the dark box so that it can test 30-40 PMTs at one time • The dark box modification projects are: • Adjusting the layout of the dark box • Stepper Motor • Filter Wheel • Increasing the amount of light to the Photodiode • Faster Transistor for the Pulsing Circuit • Charge Cable • Optics
The Stepper Motor • The stepper motor will be used to move components around inside the dark box • Before this summer Jori Ruppert-Felsot worked with the stepper motor • Then when the summer began John Patti and Mike Griswold finished up the task
The Filter Wheel • The filter wheel will be used to vary the intensity of the light goes to the PMT • The stepper motor will rotate the filter wheel
The Photodiode Needs More Light • Three different attempts at supplying the Photodiode with more light have been attempted this summer • Mainly Jori Ruppert-Felsot, Dan Dombeck, and I have been working on this • For the most part all attempts have been unsuccessful • Using a faster transistor or a circuit that incorporates two transistors • Hooking a charge cable up to the LED • Setting up an optics system that can focus light onto the Photodiode
PMT Aging Experiment • About one month ago we received a new 4th generation PMT (8C28R3) from CERN • We proceeded to test its aging characteristics • The new PMT was pulsed at a number of different frequencies for one week • The tests on this PMT ran for time intervals of approximately 24 hours • During our testing, the PMT experienced an equivalent of 50 years of running at ATLAS • Important Quantities: Npe and the Gain
Conclusions and Then Continuation • We concluded that the gain of the new 4th generation PMT actually increased slowly while it was being pulsed for 50 equivalent years • This is rather odd. The PMT’s performance is seemingly improving as it ages?! • Possible explanation: charge may be collecting on the walls of the PMT, thus creating an electric field that focuses the e- • We then proceeded to perform more aging experiments on older 3rd generation PMTs that we had available in our lab
Topic 4 The UIUC ATLAS TileCal Web Site
A New Look • During the middle of the summer I completely revamped our ATLAS Web Site • The URL for our Site is:http://web.hep.uiuc.edu/atlas/ • But lets first check out what the Old Site looked like
Thank You’s • I would like to thank the following people for teaching me so much this summer: • Jori Ruppert-Felsot • John Patti • Mike Griswold • Daniel Dombeck • And especially: • Dr. Steven Errede
The Musings of John Patti • This was John’s reaction when I told him how much work I was going to put into my presentation