slhc tracker layout
DESCRIPTION
SLHC Tracker Layout. The UTOPIAn Perspective. Charles Young (SLAC). SLHC Parameters. Peak luminosity ~ 10 35 cm -2 sec -1 Average luminosity 4 x 10 34 cm -2 sec -1 Instantaneous rate important for detector layout and design purposes: Number of events per bunch crossing Bunch spacing - PowerPoint PPT PresentationTRANSCRIPT
SLHC Tracker LayoutThe UTOPIAn Perspective
Charles Young (SLAC)
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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?
confId=45460#2009-02-27
• Early Separation (ES)
• Full Crab Crossing (FCC)
• Large Piwinski Angle (LPA)
• Low Emittance (LE) Large Emittance (LE)
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Luminosity Evolution
averageluminosity
From
FZ
’s t
alk
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# Events per Crossing
From
FZ
’s t
alk
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– 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 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?confId=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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Primary Vertex Density
Nominal LHC
ES FCC LE LPA
Peak Luminosity
1034 cm-2 sec-
1
1.0 15.5 15.5 16.3 10.7
(luminous) cm 4.5 3.7 3.7 1.6 5.3
Nevent 19 75 75 75 150
/ Nevent m 2368 493 493 213 353
Density ratio =1.0 4.8 4.8 11 6.7
Nevent 19 294 294 309 403
/ Nevent m 2368 126 126 52 132
Density ratio =1.0 19 19 46 18
~20 times higher
Num
bers
fro
m FZ
’s
talk
SLHC/Upgrade ~ 100 m
lum
inosi
ty
levelin
g
Wit
hout
levelin
g
LHC/ATLAS
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z Resolution
• Modified longitudinal impact parameter, zo x sin(), resolution as a function of for pions.
ATLAS detector paper Figure 10.10
100 m
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Desired Resolution
• LHC/ATLAS: FOM ~ 2368 / 100 ~ 24.
• SLHC/Upgrade: FOM ~ 100 / z-res.
• Similar FOM implies z-res ~ 5 m. – Probably impossible.
• FOM ~ 3 or z-res ~ 30 m 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/conferenceDisplay.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!