1 Heavy flavor physics and Vertex detector. 2 People involved RNC Group Howard Wieman Hans-Georg...
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Transcript of 1 Heavy flavor physics and Vertex detector. 2 People involved RNC Group Howard Wieman Hans-Georg...
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Heavy flavor physics and Vertex detector
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People involved
RNC GroupHoward WiemanHans-Georg Ritter Fred Bieser (Lead Electronic Engineer)Howard MatisLeo GreinerFabrice RetiereEugene YamamotoKai SchwedaMarkus OldenburgRobin Gareus (Univ. of Heidelberg)
LEPSI/IReS (Strasbourg)Claude Colledani, Michel Pellicioli, Christian Olivetto, Christine Hu, Grzegorz Deptuch Jerome Baudot, Fouad Rami, Wojciech Dulinski, Marc Winter
UCIrvineStuart Kleinfelder + students
LBNL Mechanical EngineeringEric Anderssen (consultation – ATLAS Pixels)Design works
BNL Instrumentation Div (consulting)Ohio State U
Ivan Kotov
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Heavy flavor in ultra-relativistic heavy-ion collisions
Heavy Q pairformation
How many?
c/b quarks in matterThermalization?
Coalescence? Flow?
Heavy flavor hadronsto detectors
Heavy quark energy loss
High pT
LowIntermediate pT
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Measuring yields
Large uncertaintiesIn data
In theory
Way to improveMeasure and identify all charm hadrons
Measure precise spectra
STAR preliminary
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Heavy-quark energy loss
p + p
d + Aup + p
d + Aup + p
d + Au
Heavy quarks radiate less energy than light quarks (prediction)
Yield of charm and beauty (leading) hadrons less suppressed
May be measured by D → X+e- and B → X+e-
Without vertex information systematic error from background substraction
STAR preliminary
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Flow and thermalization
Flow: spectra and v2 Charm thermalization by chemistry
J. Nagle, S. Kelly, M. Gyulassy, S.B. JN, Phys. Lett. B 557, pp 26-32
e-p & e+ e- Thermal
f(c→D0) 0.557 0.483
f(c→D+) 0.232 0.21
f(c→Ds+) 0.101 0.182
f(c→c+) 0.076 0.080
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Measuring heavy flavor with the Vertex detector
GoalsHeavy flavor energy loss
Remove background
Charm flowPrecise D0 spectra
D0 v2
Charm thermalizationYield of D+, Ds
+, c+
(challenging 3 body decays)
Vertex strategySeparate charm and beauty decay product from primary tracks
Typically D0 c = 124 m
Vertex requirement: a very good vertex resolution
Position resolution < 10 m
Thickness < 0.2% of rad length to limit multiple scattering
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STAR Vertex Detector
Two layers1.5 cm radius
4 cm radius
24 ladders2 cm by 20 cm each
< 0.2% X0
~ 100 Mega Pixels
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Charm hadron reconstruction performances
System N events for 3 D0 signal
N events for 3 D+
s signal
In progressTPC+SVT 12.6 M ~500 M (K0
s + K+)
TPC+SVT+TOF 2.6 M ~1,000 M (++)
TPC+SVT+Vertex 100 K ~100 M (++)TPC+SVT+Vertex+TOF
10 K ~1 M (++)
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STAR Vertex Detector
New vertex detector centered in existing SVT, supported one end only
End view showing 3 of 6 ladder modules
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Support: thin stiff ladder concept
Under development
Will be tested for vibration in our wind tunnel
carbon composite (75 m)Young’s modulus 3-4 times steel
aluminum kapton cable(100 m)
silicon chips(50 m)
21.6 mm
254 mm
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Sensors: Active Pixel Sensors
AdvantagesPrecise
Can be thin
Rather fast
Low power
DisadvantagesSmall signal
Not that fast
NewNeed R&D
p-well p-welln-well
p-epi
p-substrate
5-20 m
CMOS electronicAnalog & digital
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Sensors: 2 generations
1st Generation: 5-10 ms readout time
MIMOSTAR1 designed by LEPSI/IRES (Strasbourg)
640*640 pixel of 30*30 m2 pitch
Purely analog
Parallel readout on-chip multiplexed to 2 kind of outputs
1 * 100MHz driver
10 * 10 MHz drivers
2nd Generation: Faster but need more R&D
R&D with UCIrvine and LEPSI/IRES
Improve charge collection and remove need for CDS
Photogate, Active reset, …
Some digital processingUp to cluster-finder?
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Readout
Analog to end of the ladder (~1 m away)Challenge to drive analog signal at 100 MHz over 1m
Piggy back chipADC and memory on a chip bounded to the pixel chip
On-chip processing in 2nd generation
Data reduction at the end of the ladderHardware reduction (zero suppression)
Single board computer
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Budget
FY02-FY04 LBNL LDRD (total 375K$)FY04 RHIC R&D (200 K$ through Brookhaven)
Expected to continue until project is funded
Preparing a strategic LDRD fund request geared towards the development of future tracking apparatus with the Physics Division (Linear Collider)
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The time-scale
Proposal in April 2004
1st ladder prototype this fall (2004)Investigate mechanical support, cabling and some readout issues
Sensor: MIMOSA5 large but slow and “noisy”
2nd ladder prototype next year (fall 2005)Sensor: MIMOSTAR1 (submitted in July)
R.Gareus’s Readout chip (submitted in July)
The real thing starting in 2006Pending funding and success of prototypes
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Summary
A lot of work ahead of us!