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The UIUC ATLAS TileCal Project Niall Nethercote UIUC High Energy Physics Summer 1998 Project Head -...
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Transcript of The UIUC ATLAS TileCal Project Niall Nethercote UIUC High Energy Physics Summer 1998 Project Head -...
The UIUC ATLAS TileCal ProjectThe UIUC ATLAS TileCal Project
Niall NethercoteUIUC High Energy Physics
Summer 1998
Project Head - Dr. Steven ErredeProject Head - Dr. Steven Errede
ContentsContents
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
Experimental Particle PhysicsExperimental Particle Physics
Particle Accelerating FacilityParticle Accelerating Facility
Accelerating Ring Detector
How is a Particle Detected?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)
The World-Wide ATLAS ProjectThe World-Wide ATLAS Project
CERNCERN
CERN is the European Laboratory for Particle Physics
CERN is located in both France and Switzerland
It is very near Geneva, Switzerland
The LHC ProjectThe LHC Project
Large Hadron Collider (LHC) Ring Compact Muon Solenoid (CMS) Detector A Toroidal LHC Apparatus (ATLAS) Detector
CERN is upgrading in three major ways
The ATLAS ProjectThe 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
The UIUC ATLAS TileCal ProjectThe UIUC ATLAS TileCal Project
UIUC and ATLASUIUC and ATLAS
What part of ATLAS does the UIUC group work with?
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
The Scintillating Tile Hadron Calorimeter (pictured green)
What Does the UIUC Group Do?What Does the UIUC Group Do?
The UIUC ATLAS project is two-folded– Sub-Module Fabrication– Photomultiplier Tube (PMT) Testing
Hadron DetectionHadron 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 FabricationSub-Module Fabrication
UIUC’s sub-module assignment Glue machine Prototype sub-module production
The Sub-Module AssignmentThe Sub-Module Assignment
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
UIUC is responsible for producing 200 extended barrel sub-modules
Glue MachineGlue 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 ProductionSub-Module Prototype Production
During the Winter of 1996-1997 we constructed some prototype sub-modules
Photomultiplier Tube (PMT) TestingPhotomultiplier 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 AssignmentThe 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 LaboratoryOur Laboratory
Here is a shot of Dr. Errede’s Laboratory
Note the crates and the dark box
Our Dark BoxOur 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 BoxInside the Dark Box
This is our PMT testing layout that is housed in the dark box
Dark Box ModificationDark 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 MotorThe 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 WheelThe 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 LightThe 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 ExperimentPMT 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
PMT Aging Experiment ResultsPMT Aging Experiment Results
PMT Aging Experiment ResultsPMT Aging Experiment Results
Conclusions and Then ContinuationConclusions 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
The UIUC ATLAS TileCal Web SiteThe UIUC ATLAS TileCal Web Site
A New LookA 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’sThank You’s
I would like to thank the following people for teaching me so much this summer:
– Jori Ruppert-Felsot – John Patti– Mike Griswold
And especially:
– Dr. Steven Errede
– Daniel Dombeck
The Musings of John PattiThe Musings of John Patti
This was John’s reaction when I told him how much work I was going to put into my presentation