Commissioning Status of the Drift Chamber for a
Di-Muon Spectrometer at the E906/SeaQuest
Experiment at Fermilab
Florian Sanftl, 柴田研究室
2011年10月24日, GCOEコロキウム @ 東工大
Outline
1)
2)
3)
4)
Physics Motivation & Introduction
E906/SeaQuest: Physics Goal
Muon Pair Spectrometer
Design and Commissioning of Drift Chamber built by
Japanese Group
5) Track Reconstruction Algorithm / XT curve / position
resolution of charged particles
6) Conclusion & Outlook
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1) Physics Introduction & Motivation
What is the Proton?
 Three “Valence” quarks
Proton
 2 “up” quarks (q = +⅔)
 1 “down” quark (q = -⅓)
 Bound together by gluons
 Gluons can split into quarkantiquark pairs (similar to the
photon splitting into a electronpositron pair)
 The Proton “Sea” is formed of
quarks and antiquarks
Sea-quarks
Gluons
e+
Photon
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Purpose of our Study
Is ū = đ valid in the Proton?
Is there a Flavor Asymmetry of Anti-quarks
in the Proton?
đ - ū ≠ 0?
đ/ū ≠ 1?
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How can we measure Sea-Quarks?
Deep Inelastic Scattering (DIS)
Drell-Yan Process
90° Rotation
Proton / Beam
Proton / Target
Proton

Electron beam scatters off a proton

 Electromagnetic interaction
between electron and quark
 Comparing electron before and
after interaction reveals information
about the proton structure
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Proton beam scatters off a proton
 Quark and anti-quarks annihilate
into virtual photon
 Virtual photon decays into two
muons
 Anti-quarks can be selected
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Importance of ‘Bjorken-x’ xB and Q2


Q2 :
4-momentum transferred squared
(“virtuality of photon”)
Q2 = -q2 = 2EeE’e(1+cosθl)
Alternative way for Q2:
Q2 also represents spatial resolution
where proton is probed
r = hc/Q = 0.2fm/Q[GeV]
typically Q2 > 1GeV2, r < 0.2*10-15 m


2011年10月24日
GCOEコロキウム @ 東工大
Bjorken-x:
xB = fractional momentum carried
by the struck quark
xB = pQUARK / pPROTON
 0 ≤ xB ≤ 1
q(xB,Q2):
probability to hit a quark with
flavour q, xB and Q2
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Experimental Results
 NA51 (Drell-Yan)
 NMC (Gottfried Sum Rule)
 E866/NuSea (Drell-Yan)
đ-ū
đ/ū
ū≠đ
Unknown
effects
apparently
dilutes meson
cloud effects
at large-x
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2) The E906/SeaQuest Experiment
Old Experiment:
Fermilab E866/NuSea
 1H, 2H, and nuclear targets
 800 GeV proton beam
New Experiment:
Fermilab E906/SeaQuest
 1H, 2H, and nuclear targets
 120 GeV proton Beam
 Higher Cross section and
 Less Background
50x statistics!!
Main
Injector
120 GeV
Tevatron
800 GeV
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Physics Goal
E906/Drell-Yan will extend
old measurements to
xB values > 0.3
and reduce statistical
uncertainty.
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3) Muon Pair Spectrometer
Station 3:
NEW from Tokyo Tech
Drawing: T. O’Connor
and K. Bailey
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Motivation: Re-do, Re-use & Re-cylce 
Expect to start collecting data this autumn!
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St. 4 Prop Tubes: Homeland Security via Los Alamos
St. 3 & 4 Hodo PMT’s: E-866, HERMES, KTeV
St. 1 & 2 Hodoscopes: HERMES
St. 2 & 3Minus- tracking: E-866
St. 3: NEW from Japanese Collaborators
St. 2 Support Structure: KTeV
Target Flasks: E-866
Cables: KTeV
• 2nd Magnet: KTeV Analysis Magnet
• Hadron Absorber: Fermilab Rail Head???
• Solid Fe Magnet Coils: E-866 SM3 Magnet
• Shielding blocks: old beamline (Fermilab Today)
• Solid Fe Magnet Flux Return Iron: E-866 SM12 Magnet
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Spectrometer Top View
μ+
25 m
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4) Design of the New Drift Chamber
μ+ / μGeneral Performance requirements
• Detection Area:
1.6 m (vertical) x 2.2 m (horizontal)
• 6 Active layers:
U/U’ (+14°), X/X’ (0°), V/V’ (-14°)
• Position resolution: < 400 μm per plane
Gas Selection:
• For now: Argon:CO2 (80:20)
Cell Structure
• Cell width & height 20 mm
• Wire spacing 10 mm
• Diameter sense wire (Au-W) 30 μm,
others (Au-CuBe) 80 μm
Performance Parameters
• Gas-gain ~4.0E5
• Drift velocity 3-6 cm / μsec (Ar:CO2)
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U’
X
X’
V
V’
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Commissioning Timeline
STATUS of
Station 3+ DC
June, 2009
Design completed
Fabrication
completed
January, 2010
March, 2010
Transport to RIKEN
Tests at RIKEN
July, 2010
Transport to Fermilab
Tests at Fermilab
Now
Installation &
Setup in
Spectrometer
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5) Track Reconstruction Algorithm
Cosmic Ray
Reconstructed track
Scintillator
Measure time difference
between trigger and
Signal from Chamber
Convert time to distance
by
simulation(GARFIELD)
Reconstruct
Track
(5 layer based)
Iteration
2-dim
distribution
Time vs. Distance
Project distance
distributions and fit for
position resolution
Extract new time to
distance relation
Projected
distance
Accepted
Hits
Scintillator
We are measuring:
• Coincidence between
bottom and top scintillator
caused by cosmic rays
• Time difference between
coincidence and signal
from chamber
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Results and Discussion
XT extraction:
• 1st Iteration
• Extracted curve agrees well with input
curve within uncertainties
• Still too little statistics from the edge of
cell
Deviation simulation between
measurement:
• Green bands is width of the projections
• Those are constant over a wide T range
• Band corresponds to position resolution
of 500μm
• Tilting behavior due to statistical effects
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6) Conclusion and Outlook
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E906/SeaQuest is a Drell-Yan experiment
It measures the asymmetry of anti-quarks in the proton
Tokyo Tech group designed and built and a new drift chamber
We prepared a Track Reconstruction Algorithm
Algorithm is working well
We already achieved a position resolution of 500μm which is very
close to the design value of 400μm
• Improvement by more iterations
• We are ready for the first beam in November 2011!!!
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The E906 Collaboration
Abilene Christian University
Obiageli Akinbule
Brandon Bowen
Mandi Crowder
Tyler Hague
Donald Isenhower
Ben Miller
Rusty Towell
Marissa Walker
Shon Watson
Ryan Wright
Academia Sinica
Wen-Chen Chang
Yen-Chu Chen
Shiu Shiuan-Hal
Da-Shung Su
Argonne National Laboratory
John Arrington
Don Geesaman*
Kawtar Hafidi
Roy Holt
Harold Jackson
David Potterveld
Paul E. Reimer*
Josh Rubin
University of Colorado
Joshua Braverman
Ed Kinney
Po-Ju Lin
Colin West
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Fermi National Accelerator Laboratory
Chuck Brown
David Christian
University of Illinois
Bryan Dannowitz
Dan Jumper
Bryan Kerns
Naomi C.R Makins
Jen-Chieh Peng
KEK
Shin'ya Sawada
Ling-Tung University
Ting-Hua Chang
Los Alamos National Laboratory
Gerry Garvey
Mike Leitch
Han Liu
Ming Xiong Liu
Pat McGaughey
University of Maryland
Prabin Adhikari
Betsy Beise
Kaz Nakahara
University of Michigan
Brian Ball
Wolfgang Lorenzon
Richard Raymond
National Kaohsiung Normal University
Rurngsheng Guo
Su-Yin Wang
GCOEコロキウム @ 東工大
RIKEN
Yuji Goto
Atsushi Taketani
Yoshinori Fukao
Manabu Togawa
Rutgers University
Lamiaa El Fassi
Ron Gilman
Ron Ransome
Elaine Schulte
Brian Tice
Ryan Thorpe
Yawei Zhang
Texas A & M University
Carl Gagliardi
Robert Tribble
Thomas Jefferson National Accelerator
Facility
Dave Gaskell
Patricia Solvignon
Tokyo Institute of Technology
Toshi-Aki Shibata
Kenichi Nakano
Florian Sanftl
Shintaro Takeuchi
Shou Miyasaka
Yamagata University
Yoshiyuki Miyachi
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Flavor Asymmetry: Models
 Pauli Blocking:
Excess of up-quarks permits creation of up-anti-up-pairs
 Meson Cloud in the nucleon—Sullivan process in DIS
Antiquarks in spin 0 object → No net spin
 Chiral Quark models—effective Lagrangians
LALP98-56
 Instantons
 Statistical Parton Distributions
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