Transcript Utopia Young

SLHC Tracker Layout
The UTOPIAn Perspective
Charles Young (SLAC)
SLHC Parameters
• Peak luminosity ~ 1035 cm-2 sec-1
• Average luminosity 4 x 1034 cm-2 sec-1
• Instantaneous rate important for detector
layout and design purposes:
– Number of events per bunch crossing
– Bunch spacing
• 25 or 50 nsec
– Detector integration time
• One BC (at 25 nsec separation)
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Four SLHC Scenarios
• Frank Zimmermann: four scenarios during
February 2009 ATLAS Upgrade Week.
– http://indico.cern.ch/conferenceDisplay.py?confI
d=45460#2009-02-27
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Early Separation (ES)
Full Crab Crossing (FCC)
Large Piwinski Angle (LPA)
Low Emittance (LE) a Large Emittance (LE)
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From FZ’s talk
Luminosity Evolution
average
luminosity
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From FZ’s talk
# Events per Crossing
Max = 400
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With Luminosity Leveling
Min = 75
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What is UTOPIA?
• A very bad acronym for Upgrade Taskforce On Possible
Innerdetector Layout
• Members
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Leonardo Rossi (Genova - chair)
Andrea Catinaccio (CERN)
Allan Clark (Geneva)
Nigel Hessey (NIKHEF)
Nikos Konstantinidis (UC London)
Andi Salzburger (CERN- DESY)
Teddy Todorov (Annecy)
Jeff Tseng (Oxford)
Norbert Wermes (Bonn)
Charlie Young (SLAC)
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Mandate
• The mandate is to define a baseline layout for the central
tracker in view of the Letter of Intent ATLAS will write for the
SLHC.
• As the physics focus of SLHC is not defined yet, we require
that the new layout has at 1035cm-2s-1 the same
performance as the present detector is expected to have at
1034cm-2s-1.
• We should also take into proper consideration the need to
build & commission such a detector in a relatively short
time (~ 5 years).
• The new layout should be optimized for the inner tracker,
including pixel, short strip and long strip, and barrel plus
endcap simultaneously.
• The Task Force is expected to reach a result by October
and then hand over the information to the LoI editors.
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UTOPIA Meetings
• Meeting every 3 weeks
– Six meetings so far
– http://indico.cern.ch/categoryDisplay.py?categId
=1389
• Some agenda items
– Encourage comparison/validation of tools
– Suggest layout with material estimates
– Power estimate a cooling
– Other considerations and wild ideas
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Current “A Basic Layout”
• See presentation by Nigel Hessey
(http://indico.cern.ch/conferenceDisplay.py?c
onfId=61990)
• 4 pixel layers, 3 short strip layers and 2 long
strip layers
• “Fixed length” barrel
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Power Estimates
• See presentations by Norbert Wermes
(http://indico.cern.ch/conferenceDisplay.py?confId
=59516) and Alan Clark
(http://indico.cern.ch/conferenceDisplay.py?confId
=61990)
• Consider contributions from:
– Front end power dissipation (digital + analog)
– Losses in local cabling
– Leakage current x depletion voltage (depends on
radiation dose)
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Nominal
LHC
ES
FCC
LE
LPA
1.0
15.5
15.5
16.3
10.7
4.5
3.7
3.7
1.6
5.3
19
75
75
75
150
2368
493
493
213
353
=1.0
4.8
4.8
11
6.7
19
294
294
309
403
2368
126
126
52
132
=1.0
19
19
46
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Peak Luminosity 1034 cm-2 sec-1
Without
leveling
luminosity
leveling
s(luminous)
cm
Nevent
s / Nevent
Density ratio
Nevent
s / Nevent
Density ratio
mm
LHC/ATLAS
mm
SLHC/Upgrade
UTOPIA ~ 100 mm
~20 times higher
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Numbers from FZ’s talk
Primary Vertex Density
z Resolution
• Modified longitudinal impact parameter, zo x
sin(q), resolution as a function of h for pions.
ATLAS detector
paper Figure 10.10
100 mm
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Desired Resolution
• LHC/ATLAS: FOM ~ 2368 / 100 ~ 24.
• SLHC/Upgrade: FOM ~ 100 / z-res.
• Similar FOM implies z-res ~ 5 mm.
– Probably impossible.
• FOM ~ 3 or z-res ~ 30 mm can be useful and
not obviously impossible.
Careful studies needed to confirm
(or refute) this hand waving!
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Level-1 Track Trigger
• See presentation by
Nikos Konstantinidis (http://indico.cern.ch/co
nferenceDisplay.py?confId=59516)
• Doublet(s) – direct impact on layout
• Regional readout – no direct impact
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Computing Impact
• Pattern recognition and reconstruction time
driven by combinatorics.
• Can a layout make a (large) impact?
• Possibilities:
– Layer doublets
– More pixel layers
• What are the costs (in $ as well as physics
performance)?
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Summary from UTOPIA
• Come up with a basic layout by October
• Targeted for Letter of Intent
• Upgrade Simulation group doing the hard
work!
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