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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
Experimental Particle Physics
Particle Accelerating Facility
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Accelerating Ring
Detector
How is a Particle Detected?
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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
CERN
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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
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CERN is
upgrading
in three
major ways
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Large Hadron Collider (LHC) Ring
Compact Muon Solenoid (CMS) Detector
A Toroidal LHC Apparatus (ATLAS) Detector
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The ATLAS Project
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144 institutes worldwide 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
UIUC and ATLAS
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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?
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The UIUC ATLAS project is two-folded
– Sub-Module Fabrication
– Photomultiplier Tube (PMT) Testing
Hadron Detection
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How are hadrons
detected with submodules 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
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UIUC’s sub-module assignment
Glue machine
Prototype sub-module production
The Sub-Module Assignment
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UIUC is
responsible for
producing 200
extended barrel
sub-modules
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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
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Glue Machine
The glue machine will be used to apply
very precise amounts of glue to the submodules
 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
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Sub-Module Prototype Production
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During the Winter of
1996-1997 we
constructed some
prototype sub-modules
Photomultiplier Tube (PMT) Testing
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General
– UIUC’s PMT testing assignment
– Our PMT testing setup
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The work that we did this summer
– Dark Box modification
– PMT Aging experiments
The PMT Testing Assignment
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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
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Here is a shot of Dr. Errede’s Laboratory
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Note the crates and the dark box
Our Dark Box
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Here the crates are
on the left, the dark
box is on the right,
and that’s Jori walking
into the lab
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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
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This is our PMT
testing layout that is
housed in the dark
box
Dark Box Modification
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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
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– Increasing the amount of light to the Photodiode
Faster Transistor for the Pulsing Circuit
 Charge Cable
 Optics
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The Stepper Motor
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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
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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
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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
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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
Conclusions and Then Continuation
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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 eWe 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
A New Look
During the middle of the summer I
completely revamped our ATLAS Web
Site
 The URL for our Site is:
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http://web.hep.uiuc.edu/atlas/
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But lets first check out what the Old Site
looked like
Thank You’s
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I would like to thank the following
people for teaching me so much this
summer:
– Jori Ruppert-Felsot
– Daniel Dombeck
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And especially:
– Dr. Steven Errede
– John Patti
– Mike Griswold
The Musings of John Patti
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This was John’s reaction when I told him how much
work I was going to put into my presentation