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