ATLASreu97

The UIUC ATLAS TileCal Project: 

The UIUC ATLAS TileCal Project Niall Nethercote UIUC High Energy Physics Summer 1998 Project Head - Dr. Steven Errede

Contents: 

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

Experimental Particle Physics: 

Experimental Particle Physics

Particle Accelerating Facility: 

Particle 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 Project: 

The World-Wide ATLAS Project

CERN: 

CERN CERN is the European Laboratory for Particle Physics CERN is located in both France and Switzerland It is very near Geneva, Switzerland

Enlargement of the LHC: 

Enlargement of the LHC

The LHC Project: 

The 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 Project: 

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

The UIUC ATLAS TileCal Project: 

The UIUC ATLAS TileCal Project

UIUC and ATLAS: 

UIUC 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 Detection: 

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: 

Sub-Module Fabrication UIUC’s sub-module assignment Glue machine Prototype sub-module production

The Sub-Module Assignment: 

The 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 Machine: 

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: 

Sub-Module Prototype Production During the Winter of 1996-1997 we constructed some prototype sub-modules

Photomultiplier Tube (PMT) Testing: 

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: 

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: 

Our Laboratory Here is a shot of Dr. Errede’s Laboratory Note the crates and the dark box

Our 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: 

Inside the Dark Box This is our PMT testing layout that is housed in the dark box

Dark Box Modification: 

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 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 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: 

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: 

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

PMT Aging Experiment Results: 

PMT Aging Experiment Results

PMT Aging Experiment Results: 

PMT Aging Experiment Results

Conclusions and Then Continuation: 

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

The UIUC ATLAS TileCal Web Site: 

The UIUC ATLAS TileCal Web Site

A New Look: 

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: 

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 And especially: Dr. Steven Errede Daniel Dombeck

The Musings of John Patti: 

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