R

1
RD for Future Detectors

• Detector RD continues on many fronts
• Future Detectors will include
• Neutrino detectors
• Massive, high efficiency
• Hadron B Factory, Rare Kaon Decay, ?/Charm
  Detectors
• High bandwidth, high precision
• Linear Collider Detectors
• Precision measurements
• I will concentrate on the Linear Collider
  Detector RD

2
Linear Collider Detector Requirements

• Both Physics and Accelerator Constraints dictate
  the Detector Requirements
• Linear Collider creates new challenges and
  opportunities, different in many respects from
  the challenges and opportunities of the LHC
  detectors
• Physics motivates
• Triggerless event collection (software event
  selection)
• Extremely precise vertexing
• Synergistic design of detectors components
• vertex detector, tracker, calorimeters
  integrated for optimal jet reconstruction
• New technologies based on recent detector
  inventions
• Detector RD of Next Few Years is Critical

3
Collider Constraints
X-Band GLC/NLC SuperRF TESLA
bunch/train 192 2820
train/sec 150/120 5
bunch spacing 1.4 nsec 337 nsec
bunches/sec 28800/23040 14100
length of train 269 nsec 950 msec
train spacing 6.6/8.3 msec 199 msec
crossing angle 7-20 mrad 0-20 mrad

• Linear Collider Detector RD has had to consider
  two different sets of collider constraints
  X-Band RF and Superconducting RF designs
• With the linear collider technology selection,
  the detector efforts can concentrate on one set
  of parameters
• The ILC creates requirements similar to those of
  the TESLA design

4
Linear Collider Events

• Simple events (relative to Hadron collider) make
  particle level reconstruction feasible
• Heavy boson mass resolution requirement sets jet
  energy resolution goal

5
Calorimetry

• Current paradigm Particle/Energy Flow (unproven)
• Jet resolution goal is 30/?E
• In jet measurements, use the excellent resolution
  of tracker, which measures bulk of the energy in
  a jet

Headroom for confusion
Particles in Jet Fraction of Visible Energy Detector Resolution
Charged 65 Tracker lt 0.005 pT negligible
Photons 25 ECAL 15 / ?E
Neutral Hadrons 10 ECAL HCAL 60 / ?E
6
Energy/Particle Flow Calorimetry
Follow charged tracks into calorimeter and
associate hadronic showers
Identify EM clusters not associated with charged
tracks (gammas)
Remaining showers will be the neutral hadrons
7
EM Calorimetry

• Physics with isolated electron and gamma
• energy measurements require 10-15 / ?E ? 1
• Particle/Energy Flow requires fine grained EM
• calorimeter to separate neutral EM clusters
• from charged tracks entering the calorimeter
• Small Moliere radius
• Tungsten
• Small sampling gaps so not to spoil RM
• Separation of charged tracks from jet core helps
• Maximize BR2
• Natural technology choice Si/W calorimeters
• Good success using Si/W for Luminosity monitors
  at SLD, OPAL, ALEPH
• Oregon/SLAC/BNL
• CALICE
• Alternatives Tile-Fiber (challenge to achieve
  required granularity)
• Scintillator/Silicon Hybrid
• Shaslik
• Scintillator Strip

material RM
Iron 18.4 mm
Lead 16.5 mm
Tungsten 9.5 mm
Uranium 10.2 mm
8
Silicon/Tungsten EM Calorimeter

• SLAC/Oregon/BNL
• Conceptual design for a dense, fine grained
  silicon tungsten calorimeter well underway
• First silicon detector prototypes are in hand
• Testing and electronics design well underway
• Test bump bonding electronics to detectors by end
  of 04
• Test Beam in 05

9
Silicon/Tungsten EM Calorimeter (2)

• Pads 5 mm to match Moliere radius
• Each six inch wafer read out by one chip
• lt 1 crosstalk
• Electronics design
• Single MIP tagging (S/N 7)
• Timing lt 5 nsec/layer
• Dynamically switchable feedback capacitor scheme
  (D. Freytag) achieves required dynamic range
  0.1-2500 MIPs
• Passive cooling conduction in W to edge

Angle subtended by RM
GAP
10
ECAL Prototype
9720 channels in prototype
11
Preparations for DESY Beam Test
DESY late 2004
12
Other EM Calorimeters

• Tile-fiber
• Interesting readouts, such as SiPM
• Option shower max (scintillator strips or
  silicon pads)

Russia, ITEP
Silicon Photomultiplier
KEK, Kobe, Konan, Niigata, Shinshu, Tsukuba
Colorado
13
Other EM Calorimeters (2)

• Silicon-scintillator Hybrid
• Scintillator strip
• Shashlik

KEK, Kobe, Konan, Niigata, Shinshu, Tsukuba
14
Hadron Calorimetry

• Role of Hadron Calorimetry in the Energy/Particle
  Flow
• Isolate and measure neutral hadrons
• Approaches
• Technology
• RPCs (Note promising work at IHEP-Beijing on
  oil-less resistive plate)
• GEMs
• Tile-fiber w/ APD SiPM HPD EBCCD
• Scintillator strips
• Readout
• Analog
• Digital high granularity

15
MINICAL Prototype
Electron resolution in hadron calorimeter

• Studied different readout systems (PM, SiPM, APD)
• Established reliable calibration system, checked
  long term stability, established detailed MC
  simulation
• Developed stability monitoring system

In 2005 move to hadron beam to fully test HCAL
performance
Hamburg, DESY, Dubna, MEPhI, Prague, LPI, ITEP
16
Digital Hadron Calorimetry

• 1 m3 prototype planned to test concept
• Lateral readout segmentation 1 cm2
• Longitudinal readout segmentation layer-by-layer
• Gas Electron Multipliers (GEMs) and Resistive
  Plate Chambers (RPCs) evaluated
• Objectives
• Validate RPC approach (technique and physics)
• Validate concept of the electronic readout
• Measure hadronic showers with unprecedented
  resolution
• Validate MC simulation of hadronic showers
• Compare with results from Analog HCAL

Argonne National Laboratory
Boston University
University of Chicago
Fermilab
University of Texas at Arlington
17
Tracking

• Tracking for any modern experiment should be
  conceived as an integrated system, combined
  optimization of
• the inner tracking (vertex detection)
• the central tracking
• the forward tracking
• the integration of the high granularity EM
  Calorimeter
• Pixelated vertex detectors are capable of track
  reconstruction on their own, as was demonstrated
  by the 307 Mpixel CCD vertex detector of SLD, and
  is being planned for the linear collider
• Track reconstruction in the vertex detector
  impacts the role of the central and forward
  tracking system

18
Inner Tracking/Vertex Detection

• Detector Requirements
• Excellent spacepoint precision ( lt 4 microns )
• Superb impact parameter resolution ( 5µm ?
  10µm/(p sin3/2?) )
• Transparency ( 0.1 X0 per layer )
• Track reconstruction ( find tracks in VXD alone )
• Concepts under Development for Linear Collider
• Charge-Coupled Devices (CCDs)
• demonstrated in large system at SLD
• Monolithic Active Pixels CMOS (MAPs)
• DEpleted P-channel Field Effect Transistor
  (DEPFET)
• Silicon on Insulator (SoI)
• Image Sensor with In-Situ Storage (ISIS)
• HAPS (Hybrid Pixel Sensors)

19
Inner Tracking/Vertex Detection (CCDs)

• Issues
• Readout speed and timing
• Material budget
• Power consumption
• Radiation hardness

• RD
• Column Parallel Readout
• ISIS
• Radiation Damage Studies

20
Column Parallel CCD

• SLD Vertex Detector designed to read out
  800 kpixels/channel at 10 MHz, operated at 5 MHz
  gt readout time 200 msec/ch
• Linear Collider demands 250 nsec readout for
  Superconducting RF time structure
• Solution Column Parallel Readout
• LCFI (Bristol, Glasgow, Lancaster, Liverpool,
  Oxford, RAL)

(Whereas SLD used one readout channel for each
400 columns)
21
Column Parallel CCD (2)

• Next Steps for LCFI RD
• Bump bonded assemblies
• Radiation effects on fast CCDs
• High frequency clocking
• Detector scale CCDs w/ASIC cluster finding
  logic design underway production this year

• In-situ Storage Devices
• Resistant to RF interference
• Reduced clocking requirements

22
Image Sensor with In-situ Storage (ISIS)

• EMI is a concern (based on SLC experience) which
  motivates delayed operation of detector for long
  bunch trains, and consideration of ISIS
• Robust storage of charge in a buried channel
  during and just following beam passage (required
  for long bunch trains)
• Pioneered by W F Kosonocky et al IEEE SSCC 1996,
  Digest of Technical Papers, 182
• T Goji Etoh et al, IEEE ED 50 (2003) 144 runs up
  to 1 Mfps.

• charge collection to photogate from 20-30 mm
  silicon, as in a conventional CCD
• signal charge shifted into stor. register every
  50ms, providing required time slicing
• string of signal charges is stored during bunch
  train in a buried channel, avoiding
  charge-voltage conversion
• totally noise-free charge storage, ready for
  readout in 200 ms of calm conditions between
  trains for COLD LC design
• particles which hit the storage register (30
  area) leave a small direct signal (5 MIP)
  negligible or easily corrected

23
Radiation Effects in CCDs
N. Sinev et al.

• Drift of charge over long distance in CCD makes
  detector very susceptible to effects of
  radiation
• Transfer inefficiency
• Surface defects

Traps can be filled

• neutrons induce damage clusters
• low energy electrons create point defects but
  high energy electrons create clusters Y.
  Sugimoto et al.
• number of effective damage clusters depends on
  occupation time some have very long trapping
  time constants modelled by K. Stefanov

Hot pixels

• Expect 1.5x1011/cm2/yr of 20 MeV electrons at
  layer-1
• Expect 109/cm2/yr 1 MeV-equivalent dose from
  extracted beamline

24
Inner Tracking/Vertex Detection (MAPs)

• Concept
• Standard VLSI chip, with thin, un-doped silicon
  sensitive layer, operated undepleted
• Advantages
• decoupled charge sensing and signal transfer
  (improved radiation tolerance, random access,
  etc.)
• small pitch (high tracking precision)
• Thin, fast readout, moderate price, SoC

• RD
• Strasbourg IReS has been working on development
  of monolithic active pixels since 1989 RAL also
  now.
• First IReS prototype arrays of a few thousands of
  pixels demonstrated the viability of technology
  and its high tracking performances.
• First large prototypes now fabricated and being
  tested.
• Current attention focussed on readout strategies
  adapted to specific experimental conditions.
• Parallel RD FAPS (RAL)
• 10-20 storage capacitors/pixel

Technology will be used at STAR
25
Inner Tracking/Vertex Detection (DEPFET)

• Properties
• low capacitance ? low noise
• Signal charge remains undisturbed by readout ?
  repeated readout
• Complete clearing of signal charge ? no reset
  noise
• Full sensitivity over whole bulk ? large signal
  for m.i.p. X-ray sens.
• Thin radiation entrance window on backside ?
  X-ray sensitivity
• Charge collection also in turned off mode ? low
  power consumption
• Measurement at place of generation ? no charge
  transfer (loss)
• Operation over very large temperature range ? no
  cooling needed

• Concept
• Field effect transistor on top of fully depleted
  bulk
• All charge generated in fully depleted bulk
  assembles underneath the transistor channel
  steers the transistor current
• Clearing by positive pulse on clear electrode
• Combined function of sensor and amplifier

16x128 DEPFET-Matrix
MPI Munich, MPI Halle, U. Bonn, U. Mannheim
26
Central Tracking

• Two general approaches being developed for the
  Linear Collider
• TPC (or Jet Chamber)
• Builds on successful experience of PEP-4, ALEPH,
  ALICE, DELPHI, STAR, ..
• Large number of space points, making
  reconstruction straight-forward
• dE/dx ? particle ID, bonus
• Minimal material, valuable for calorimetry
• Tracking up to large radii
• Silicon
• Superb spacepoint precision allows tracking
  measurement goals to be achieved in a compact
  tracking volume
• Robust to spurious, intermittent backgrounds
• linear collider is not storage ring

27
Central Tracking (TPC)

• Issues for LC TPC
• Optimize novel gas amplification systems
• Conventional TPC readout based on MWPC and pads
• limited by positive ion feedback and MWPC
  response
• Improvement by replacing MWPC readout with
  micropattern gas chambers (eg. GEMs, Micromegas)
• Small structures (no E?B effects)
• 2-D structures
• Only fast electron signal
• Intrinsic ion feedback suppression
• Neutron backgrounds
• Optimize single point and double track resolution
• Performance in high magnetic fields
• Demonstrate large system performance with control
  of systematics

28
TPC Gas Amplification System

• New concept for gas amplification at the end
  flanges
• Replace proportional wires with Micro Pattern Gas
  Detectors
• Gas Electron Multiplier (GEM) - F. Sauli, 1997
• or Micromegas - Y. Giomataris et al., 1996

GEM
Conventional TPC Wires
Small structures (no E?B effects) 2-D
structures Only fast electron signal Intrinsic
ion feedback suppression
Also being investigated Medipix2, CMOS pixel
sensor w/GEM (NIKHEF, Saclay, Twente/Mesa, CERN)
29
Gas Electron Multiplier (GEM) for TPC Readout

• 50 µm kapton foil,
• double sided copper coated
• 75 µm holes, 140 µm pitch
• GEM voltages up to 500 V
• yield 104 gas amplification

Use GEM towers for safe operation (COMPASS)
30
Micromegas for TPC Readout

• asymmetric parallel plate chamber
• with micromesh
• saturation of Townsend coefficient
• mild dependence of amplification
• on gap variations
• ion feedback suppression

31
TPC Resolution Studies with Magnetic Field
and 1 T at Triumf
32
TPC Resolution and Ion Feedback
TPC Resolution
GEM
Magnetic field improves resolution
P5 gas
Double-GEM
33
Central Tracking (Silicon)

• With superb position resolution, compact tracker
  is possible which achieves the linear collider
  tracking resolution goals
• Compact tracker makes the calorimeter smaller and
  therefore cheaper, permitting more aggressive
  technical choices (assuming cost constraint)
• Linear Collider backgrounds (esp. beam loss)
  extrapolated from SLC experience also motivate
  the study of silicon tracking detector, SiD
• Silicon tracking layer thickness
• determines low momentum
• performance
• 3rd dimension may be achieved
• with segmented silicon strips,
• or silicon drift detectors

(1.5 / layer)
(TPC)
34
Central Tracking (Silicon)

• Optimizing the Configuration

support
Cooper, Demarteau, Hrycyk
R. Partridge
H. Park
35
Central Tracking (Silicon)

• Strip length
• Short strips segments (10 cm slices) are
  interesting for less noise, shorter shaping time,
  better time stamping.
• Longer strips, long shaping time designs are also
  under development, motivated by minimized
  material in tracking volume.
• Two ASICs for long shaping will soon go to fab.

Santa Cruz ASIC power cycle
LPNHE Preamp
Note, silicon detector RD also supports TPC
detector where intermediate and forward tracking
are needed
36
Silicon Tracking w/ Calorimeter Assist
Primary tracks started with VXD reconstr.
V0 tracks reconstructed from ECAL stubs
E. von Toerne
37
Very Forward Instrumentation

• Hermiticity depends on excellent coverage in the
  forward region, and forward system plays several
  roles
• maximum hermiticity
• precision luminosity
• shield tracking volume
• monitor beamstrahlung
• High radiation levels must be handled
• 10 MGy/year in very forward detectors

TESLA Goal ?L/L 10-4 (exp.)
?L/L 10-4 (theo.) Ref OPAL (LEP) ?L/L
3.4 x 10-4 (exp.) ?L/L 5.4 x 10-4 (theo.)
38
Machine Detector Interface

• A critical area of detector RD which must be
  optimized is where the detector meets the
  collider
• Preserve optimal hermiticity
• Preserve good measurements
• Control backgrounds
• Quad stabilization

Zero crossing angle, TPC detector
20 mr crossing angle, silicon detector
39
Detector Beamline Instrumentation

• Polarized electrons (and perhaps positrons)
• Polarimeter
• 0.2 goal
• Electron energy
• Energy spectrometer
• 200 ppm required
• Beam energy profile
• Differential luminosity measurement
• knowledge of beamstrahlung effects required

S. Boogert
40
Other Detector RD Efforts

• Muon Detectors
• RPCs
• Scintillator strips w/ MAPMTs
• Detector Solenoid
• All detector concepts under study assume a strong
  magnetic field of strength greater than 3T with a
  coil of large diameter.
• The large volume required for this high-field
  magnet is a challenge, but experience with the 4T
  solenoid for CMS will be very helpful.
• This experience has been utilized in detector
  designs, but requires additional understanding.
• Need to study compensation issues if machine has
  a crossing angle.
• Quad stabilization
• Machine-detector-interface issue crucial for the
  detector.

41
Summary

• Linear Collider Experimental Program needs
  advances in detector technology specific to the
  challenges of the LC
• High granularity, high precision, triggerless
  operation
• A coordinated, RD effort is underway world-wide
  to develop the advanced detectors needed to
  capitalize on the special discovery opportunities
  which will be created by the construction of the
  linear collider.
• The Detector community has been preparing, but
  eagerly awaiting the technology choice to make
  the focused RD program.
• With the technology decision, it is now time for
  a significant ramping up of this effort.