CMS upgrade at SLHC

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• CMS upgrade at SLHC
• M de Palma
• INFN-Univ di Bari
• LHC experiments (Atlas and CMS) were designed
  for 10 years operation
• at L 1034 cm-2s-1 therefore to operate at SLHC
  (L 1035 cm-2s-1 ) they must
• be upgrade.

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Why more integrated luminosity after LHC?

• Improve measurements of new phenomena seen at the
  LHC. E.g.
• Higgs couplings and self-couplings
• Properties of SUSY particles (mass, decay BRs,
  etc)
• Couplings of new Z or W gauge bosons (e.g.L-R
  symmetry restoration?)
• Detect/search of low-rate phenomena inaccessible
  at the LHC. E.g.
• H?Z?
• top quark FCNCs
• 3. Push sensitivity to new high-mass scales.
• New forces ( Z, WR )
• Quark substructure
• ....

Energies/masses in the few-100 GeV
range. Detector performance at SLHC should equal
(or improve) in absolute terms the one at
LHC Very high masses, energies, rather
insensititive to high-lum. environment. Not very
demanding on detector Performance. Slightly
degraded detector performance tolerable
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Why Machine / Experiment Upgrade?

• Reasons to upgrade LHC
• MACHINEDue to the high radiation doses to which
  they will be submitted, the LHC IR quadrupole
  magnets have to be replaced after integrated
  luminosity of 700 fb-1
• EXPERIMENTS
• Depending on the luminosity evolution, the
  error halving time will exceed 5 year at this
  time

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LHCC peak Luminosity
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Detector Challenges from LHC to SLHC
Cumulative effects (NIEL, TID) increase by a
factor 5 Instantaneous effects (occupancy, SEU)
increase by a factor 10
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Physics Rates at LHC/SLHC

• At SLHC is assumed that the trigger and event
  recording rates should be controlled to the
  similar level as the initial LHC condition.
• x 10 physics rate ?
• Higher threshold for inclusive (single particle)
  triggers
• or/and
• More selective conditions (combination of signals)

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CMS Compact Muon Solenoid
Total weight 12,500 t Overall diameter 15
m Overall length 21.6 m Magnetic field 4 T
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Reference

• For tracker upgrade information, I should thanks
  all many CMS Tracker collaborators (too numerous
  to acknowledge individually) and in particular G.
  Hall
• Tracker web pageshttp//cmsdoc.cern.ch/Tracker/Tr
  acker2005/TKSLHC/index.htmlTracker Upgrade Wiki
  pageshttps//twiki.cern.ch/twiki/bin/view/CMS/SLH
  CTrackerWikiHome
• For others CMS upgrade information I refer to J.
  Nash official LHCC talk http//indico.cern.ch/con
  ferenceDisplay.py?confId41446
• and CMS Upgrades Workshop FNAL 19 Nov. 08
  http//indico.cern.ch/conferenceDisplay.py?confId
  41832

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What are the key issues?

• Phase 1
• How well do detector components handle the
  increasing luminosity?
• Both instantaneous and integrated effects
• What detector elements will need
  replacement/modification to cope?
• Detectors will record 500 fb-1, can they
  withstand this?
• Phase 2
• What detector elements will need replacement?
• Is there a requirement for a long shutdown? How
  long ? 18 Months? When?
• To operate at L 1035 cm-2s-1 most of CMS will
  survive perform well with few changes
• it is expect to upgrade trigger
  electronics DAQ
• Notable exception is tracking system (it should
  be redone).
• I will spend more time on tracking system
  upgrade

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Current Tracker system

• Two main sub-systems
• 1) Silicon Strip Tracker
• (TIB,TID,TOB,TEC)
• 210 m2 of silicon, 9.3M ch
• 73k APV25s, 38k optical links, 440 FEDs
• 27 module types

• 2) Pixels
• (BPIX,FPIX)
• 1 m2 of silicon, 66M channels
• 16k ROCs, 2k olinks, 40 FEDs
• 8 module types

Pixels quickly removable for replacement
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A better tracker for SLHC?

• Present detector looks to be very powerful
  instrument
• No physics reason to improve spatial and momentum
  measurement precision
• Key point is to maintain tracking and vertexing
  performance
• Heavy ion tracking simulations (track density
  similar to SLHC) are encouraging
• Extra pixel layer would restore losses
• Must optimise layout of tracker for
• CPU-effective track finding
• Trigger contributions
• Granularity of tracker must increase anyway
• because of leakage current/noise after
  irradiation
• as well as tracking
• Weakest point in present system is amount of
  material
• (Reducing power is only way known to improve
  this)
• from tracker perspective, least mass should be at
  lowest radii

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Tracking Trigger

• One of the key issues for CMS is the requirement
  to include some element of tracking in the Level
  1 Trigger
• One example There may not be enough rejection
  power using the muon and calorimeter triggers to
  handle the higher luminosity conditions at SLHC
• Adding tracking information at Level 1 gives the
  ability to adjust PT thresholds
• Single electron trigger rate also suffer.
• Isolation criteria are insufficient to reduce
  rate at L 1035 cm-2.s-1

Level 1 Trigger has no discrimination for PT
20 GeV/c
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Trackers issues Sensor
Substrate Outer layers, silicon looks
promising n-in-n (as for today pixel), p-type FZ
(50 cheaper, need single side processing) for
µstrips Oxygen doped, p-type/n-type MCz, High
resistivity Very inner region - no proven
alternative to silicon yet - but are other
materials possible? (Diamond? monolithic?) Perform
ance Series noise (Cdet) can decrease but
parallel (Ileak) may not (Ileak strip length,
thickness, particle fluence) Charge collection,
high bias voltage (1000 V), S/N Structure Pixel
and 3D, short strips, 2D detectors (stripxel),
SS, DS Power dissipation Manufacturability
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Trackers issues
Electronic issues Very rad-hard electronics
Single Event Upset (SEU) will be a serious
problems. Technology and design 0.13 µm or
smaller CMOS for Pixel, BiCMOS e CMOS per
strips Data rate / opto-links Power scheme as
serial powering
Design issues Dimensions sensor size, finer
pitch, number of different nodule type,. Ease of
handling and assembly We must minimize handling -
could this be done by industry? Should be base
units still the Module or Stave or Sector (could
high integration give yield problems)? Module
construction and Integration Cost Present design
originates in bottom-up approach, underestimates
many costs and difficulties. Need we approach
!
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Constrains Tracker services

• Complex, congested routes
• It will probably be impossible to replace
  cables and cooling for SLHC

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How to proceed

• We have started to think to tracker upgrade
  already from few years. The point was done in a
  two days Tracker Upgrade Workshop the 28-29
  January 09 to
• 1) review the status of all different activity
• 2) Narrow down the possible options for Phase I
  upgrade and discuss a possible
  schedule for pixel activities.
• 3) Agreed on a strategy and a road map for
• developing one Layout for Phase II
• the related studies for Simulation of
  Performances
• track triggering ideas and methods
• I try to summarizing the status.

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New Upgrade Structure
Composition of the Steering Committee

• Bilei G.M. PM Abbaneo D.
• Chiochia V. DPM Bortoletto D.
• Gill K. DPM Contardo D.
• Costa S. RM dePalma M.
• Krammer M. Feld L.
• Hall G.
• Horisberger R.
• Incandela J.
• Mannelli M.
• Kwan S.
• Sharp. P

Just approved in 12/02/09 TIB
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Possible scenario

• Phase I upgrade This will involve the pixel
  system
• The design for easy replacement simplifies
  our task
• we can replace when we are ready to do so
• and evolve it gracefully into the Phase II system
• Phase II upgrade
• A pixel system with 4 barrel layers and expanded
  endcap
• Design new outer tracker to match cost, power and
  performance needs
• Study PT layers to contribute to trigger
• Big emphasis on simulation of new layout
• The official Phase II SLHC schedule is not so
  tolerant
• a careful assessment of timescales and costs is
  required very soon

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Phase I Pixel Replacement
Slide from R. Horisberger 21 May 2008
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Phase I BPIX Replacement (1)

• After many discussions, considerations
  iterations
• 4 layer pixel system 4, 7, 11, 16 cm ? 1216
  full modules
• same sensor type (n-on-n)
• CO2 cooling based
• Ultra Light Mechanics
• Shift material budget from PCB plugs out of
  tracking eta region
• BPIX modules with long 1.2m long microtwisted
  pair cables
• ROC buffers for 1.5 x 1034 and serial binary
  readout _at_160 MHz
• Serialized binary optical readout at 320 MHz to
  old, modified px-FED
• Recycle use current AOH lasers
• Same FECs , identical TTC ROC programming

from R. Horisberger 28 Jan 2009
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Phase I BPIX Replacement (2)
Slide from R. Horisberger 28 Jan 2009
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Phase I BPIX Replacement (3)
Slide from R. Horisberger 28 Jan 2009
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Phase I FPIX Replacement

• Still 3 disks
• Investigate the possibility to have n-on-p
  material (RD with SINTEF)
• Consider alternative module-on-disk geometries
  for FPIX to maximize coverage with 4-layer BPIX
  design and minimize of module types required
• Study the FPIX readout chain in order to optimize
  the segmentation and layout of modules in
  half-disks.
• New idea on the integrated cooling/mechanical
  support structure

2x8 module on each side of all outer and inner
radius
R 144.6 mm
R 58.7 mm
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Phase II simulations status

• Different ideas and solutions should be verify
  and study with simulations.
• Software team
• - First put emphasis on developing tools
  
• ( unknown errors, absence of certain
  expected features (pileup!), bugs, CPU
• time, hard-wired detector
  descriptions,)
• - implement two strawmen models for
  detailed studies
• plus layout tool to evaluate quickly basic
  features of different designs
• The two strawmen account for two different ideas
  about tracker trigger
• Double Stack Trigger
• Cluster width Trigger

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Strawman A
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Strawman B
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The track-trigger challenge
Local Occupancy Reduction Cannot possibly
transfer all Tracker data at 40MHz ! Crossing
Frequency / Event Read-Out 40MHz / 100kHz 1 /
400 L1 Data reduction by a factor of 100 200
is a reasonable target For L1 Trigger propose
to transfer only hits from tracks with Pt 2
GeV Tracks with Pt 2 Gev are less than 1
of the Tracks inside acceptance In addition,
must provide means of rapidly reliably
identifying high Pt (isolated) tracks ( Pt
15 25 GeV) Trigger functions must not degrade
tracking performance
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Possible approach Double Stack Trigger
Pairs of Sensor Planes, for local Pt
measurement High Pt tracks point towards the
origin, low Pt tracks point away from the
origin Use a Pair of Sensor Planes, at mm
distance Pairs of Hits provide Vector, that
measure angle of track with respect to the
origin Note angle proportional to hit pair
radius Keep only Vectors corresponding to high
Pt Tracks
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Double Stack Hierarchy
Within a Stacked-Sensor Module Collect Hits
from each Sensor Match into Hit Pairs Reject
Hit Pairs from Very low Pt Tracks Pt Within a Double Stack Collect Hit Pairs from
each Sensor Doublet Module Match into Track
Vectors Reject Track Vectors with Pt 2GeV Transmit for High Pt Isolation L1
Track Trigger Primitives
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Double Stack sim. results
Stub generation A stub is created when both the
row and column difference lie within a given
range.
pT discriminating for various sensor separations
using 10,000 di-muon events with smearing
of a stacked layer at r25cm
Double Stacks spaced 10cm apart
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Double Stack Possible PT module
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Double Stack A very innovative PT module
FNAL
Sensos granularity (Short Strips vs Long
Pixels) to be study
R - f Layout
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Possible approach cluster width Trigger

• Use cluster width information to eliminate low pT
  tracks.
• Two particles with different momenta cross the
  cylindrical sensor layer at distance R from the
  interaction point.
• The lowest pT one intersects the layer producing
  a cluster of larger track width (TW).

Cluster width method, G. Parrini, F. Palla,
TWEPP-07,Prague 2007
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Cluster width Trigger schema
Need a clusterizer ASIC after the FE stage.
Functional block diagram of on-detector elec.
the comparator output is the input of the cluster
recostraction circuitry (not in fig.)
The two-step process for the transmission to the
trigger logic off detector processor. High speed
modulators and drivers are part of the goals.
Fast data links
Conceptual scheme for a Trigger using AM
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Cluster width Trigger sim. results
Preliminary studies done with a modified Strawman
A 4 detection layers at 78, 87, 97, 108 cm
(290 µm active thickness, 91.5 µm pitch (97 and
108 cm layers) and 122 µm pitch (78 and 87 cm
layers), n-type bulk, 4.65 cm strips length)
Number of tracks per sector per bunch crossing as
a function of pT in Minimum Bias events (400
events/bx)
Fraction of muons with minimum number of clusters
in any of the 70 trigger sectors
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Cluster width TriggerA possible module layout
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Some considerations

• After several years, only a few trigger/layout
  ideas
• both have significant weaknesses which need RD
• both need detail simulation
• trigger layers are inevitably much more
  power-hungry ( material)
• moreover
• from Tracker perspective, it is crucial to
  demonstrate that modules provide good tracking
  informations before worrying about perfect
  triggering
• most likely a balance between tracking and
  triggering must be adopted
• Strategy for the near future in Layout Task
  Force/Simulation WG
• Continue the development of tools and perform
  layout simulation to study
• a new Geometry A (two inner stacks 23 and 35 cm
  radii and outer layers with short strips).
• the Geometry B (stacked layout).

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Sensors WG Starting point
Based on present sensor performance and level of
expected fluence, one can draw up an initial
specification of the collected charge needed at
various radii in the inner tracker regions.
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Present knowledge on SI sensors for SLHC
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Sensors WG activity
Define with all WG a sensor layout List of a
minimal set of sensors/layer specifications
Recommendation to reduce the number of options
for sensors FOCUS on the following for RD
Material choice reduction System
integration Large scale manufacturing
Actions for Phase II -short term Follow RD
Batch submissions More study on specification
Simulate device performance Have a clear
picture of the impact of the sensor thickness
on Power consumption Signal to noise ratio
Signal over threshold
Actions for Phase II -Long term Detail of single
channels (overhang,pads..) Interconnection Design
full sensors with the correct pitches Move
toward industrialization Integration into the
modules design
RD proposals
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Sensor RD Projects (1)
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Sensor RD Projects (2)

• RD(3) Thin sensors with HPK
• (delivery of sensors late summer )
• Hints from first qualification of new devices
• Wafer Thickness
• Capacitance
• Pixel, biasing scheme
• Electrons/hole (e/h) collection
• PIXEL Signal/threshold vs thickness radiation
  damage
• Radiation hardness
• RD(4) CEC with HPK from RD(3), CNM/ITE (on
  going)
• Biasing
• AC/DC
• interconnections
• RD(1) MCZ with Helsinki TKK
• contribute to study e/h collection
• Next submission results on p-type

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Sensor RD Projects (3)

• RD(5) Radiation tolerant Microstrip pixel
• Process and device technical
  specification can be defined after a first
  feedback from RD(3) on
• Material, thickness and maybe first results on
  radiation hardness
• can be focused to a real prototypes production
• Late summer we can star the plan toward
  production
• Design few ( 3) conceptual sensor to access
  module design and operation
• RD(2) on 3D detectors
• study the possibility to use 3D sensor for
  inner pixel layers

• New Activities are foreseen
• A monolithic detector in standard very deep
  submicron CMOS technology
• Construct and test diamond pixel detector (with
  RD 42)

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About other CMS sub-detectors
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Endcap CSC Muon Phase 1 Upgrade (ME4/2)

• R-Z cross-section

Empty YE3 ready for ME4/2
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Phase 1 Muons ME4/2 upgrade motivation

• Compare 3/4 vs. 2/3 stations
• (Triggering on n out of n stations is inefficient
  and uncertain)
• Recent simulation with without the ME4/2
  upgrade
• The high-luminosity Level 1 trigger threshold is
  reduced from 48 ? 18 GeV/c

Target Rate 5 kHz
Neutron backgrounds another worry4th station
redundancy adds to trigger/ readout safety
margin Estimated 3 for LHC
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The start up RPC endcap system
RPC trigger efficiency Importance of at high h
restoration
Trigger CMS TDR, four stations
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Calorimeters/Muons Phase 2
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SLHC Phase 1 2 Upgrade Level-1 Trigger s

• Phase 1
• new information from use of more fine-grained
  information from calorimeter, forward muon
  triggers and improved algorithms
• Phase 2
• completely new hardware and new information
  with the introduction of tracking triggers.
• Phase 1 upgrade triggers designed so that they
• all modification/new hardware should meets
  requirements of Phase 2 although deployed with
  Phase 1
• provide for a natural incorporation of tracking
  trigger information in Phase 2.

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Trigger Upgrade Hardware new Standard

• It will be based on the commercial ?TCA telecom
  Standard. (This would reduce significantly
  manpower and RD costs)
• This platform will be designed to accept data
  from different detectors and support a Lv1
  tracking trigger.
• Trigger group are starting to develop a uTCA
  system utilizing 3.2 GBps links which will
  consists of
• a) A main uTCA processing card.
• b) A custom backplane.

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Upgrade Scope
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Documents
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CMS Upgrade Management
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Conclusion

• Even if it is early for detailed planning of
  phase 2 upgrades,
• the overall scope of
  the upgrade is on way to be understand.
• This is driven by the geometry/functionality of
  the new tracker
• CMS is trying systematically to develop a new
  Tracker design using simulations to define new
  layout
• We are very satisfied with the prospects for the
  present tracker
• but would like to reduce the material budget
  
• and achieve similar performance
• The inclusion of tracking information in the
  trigger is a must.
• We have to build a detailed plan by the time of
  the phase 2 TDRs, but we will also have a much
  clearer idea of the machine timescales.

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• Back_up

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(No Transcript)
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Upgrade components
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LHC Phase I
Phase-1 2013-2016 Linac-4 Approved and work has
started higher brightness Allows higher LHC
current, to Ultimate which is 2.3 times
nominal Ready to run in 2013 New Inner Triplet
focusing magnets Use spare super-conductor from
LHC magnets Larger aperture, allows ß of 0.25 m
instead of 0.55 m Install in 2012/13 shutdown In
principle also gives factor 2 on
nominal Expectation is that these two
improvements will allow a ramp-up to 3 x nominal
Conditions 70 minimum bias events per BC 700
fb-1 before phase 2
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SLHC Luminosity Scenarios

• Many machine upgrade scenarios in the past
  years
• Super-bunch, short BC (5, 10, 12.5 ns)
• Abandoned either for Machine reasons (too high
  heat from beam to remove in the beam pipe) or for
  detector use
• New machine elements and ideas
• Magnets inside the experiments for Early
  Separation schemes
• Crab cavities
• Wire correctors for Large Piwinki Angle
• Luminosity Leveling
• Impact on detectors
• LPA - Large Piwinski Angle 294 Ev/BC, 25 ns BC
• ES Early Separation400 Ev/BC, 50 ns/BC

Experimenters Choice (LHCC July 2008) no
accelerator components inside detector lowest
possible event pile up possibility of easy
luminosity leveling ? full crab crossing upgrade
LPA Large Piwinski Angle - 50 ns BC
ES Early Separation - 25 ns BC
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Pixel
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Defining a new layout

• Present design suffered from limited simulations
• we did not know how many layers would provide
  robust tracking
• pixel system was a late addition, which has an
  important impact
• the material budget estimate was not as accurate
  as desired
• A new tracker might be easy to design based on
  experience
• but provision of trigger information adds a major
  complication
• and the tools to model CMS at L 1035 were not
  in place
• major uncertainties in power delivery, sensor
  type, readout architecture

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Cheung, Tricomi
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Upgrade components
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Tracker system RD Projects
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Muon
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SLHC Luminosity Scenarios
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An idea to use tracker DT Muon at phase II

• STATIC MAPPING
• -New detector providing hits in front of MuCh
  no information on momentum or charge
• - Fiducial region defined by deviation and
  multiple scattering assuming its values a muon
  with pt 10 GeV
• Sensor to sensor fixed hardware mapping fast
• DYNAMIC MAPPING
• - Use position and direction of muon trigger
  primitive (f, ?,fB )
• -extrapolation to any tracker layer
• -fiducial region defined as a function of muon
  estimated momentum
• -logical association between muon chamber and
  tracker layer requires position to sensor
  conversion locally on tracker volume if the
  tracker is passive

P. Zotto el al Upgrade of CMS Barrel Muon
Detector http//cmsdoc.cern.ch/cms/electronics/htm
l/elec_web/docs/slhcusg/proposals/proposal_list.ht
m