# Presentation: 474498

##  Detector R&DorR&D for Future Detectors 

- Ties Behnke, DESY

-  The next big detector projects
-  Challenges for detector developments
-  Review of the state of the art in main detector areas

## The Next Generation

-  Linear e+e- Collider Detector
-  Hadron Collider of the      next generation: SLHC
-  Muon Collider? ....

- The Big Detectors of the Future:

- I will not talk about:
-  LHC detector developments
-  Tevatron detector developments
-  other “approved” projects

- I will concentrate on
-  detector systems and different options
-  some technological developments
-  future R&D directions

## Lepton vs Hadron Machines

**Challenges of Detector R&D:**
-  develop precision detector technologies
-  develop technology and techniques to harvest the    power of an LC
-  prepare for a new radiation challenge at SLHC

| Lepton Collider
Small occupancies
Small backgrounds
Small rates

Extreme precision
Focus on individual particles |  | Hadron collider
Huge occupancies
Huge backgrounds
Huge rates

Reasonable precision
Look at ensembles |
| --- | --- | --- |

- A very simple minded look at

**Notes:**
Comparison LC – LHC for detector R&D

## Detection at a Lepton Collider

- Reconstruct the 4-momentum of
- all particles (charged and neutral)
- in the event

- tt event at 350 GeV,

-  individual particles
-  charged and neutral particles
-  system aspect stressed rather   than individual sub detectors

- Concept is being pushed at
- lepton collider, but is not
- limited to this

- “Trade-name”:
- 	Energy Flow (misleading)
- 	Particle Flow

**Notes:**
Introduce concept of particle flow
picture of typical event
some definitions. 

Maybe talk about possible resolution?

## Particle Flow

- Why particle flow:

- Tracker	charged particles	60%
- ECAL 		Photons		20%
- HCAL		Neutral Hadrons	10%
- LOST             Neutrinos                   10%

- e+e-      hadrons events at 500 GeV:

- example:
- reconstruction of Z0
- decays using PFLOW

- theoretical lower limit: 14%/√E
- best achieved: 50%/√E (Zeus)

## Physics Motivation/ Goal

- Why is a new reconstruction concept needed?

- Need excellent capability to separate different final states
- Example: W-Z separation (hadronic channel): jet energy resolution

- 60%/√E

- 30%/√E

- “traditional” methods

- Particle flow

## Detector Requirements

- Particle Flow stresses:
-  reconstruction of individual particles
-  separation of particles (charged and neutral)

- Less important:
-  single particle energy resolution

- Detector requirements:
-  excellent tracking, in particular in dense jets
-  excellent granularity in the ECAL
-  “no” material in front of ECAL
-  good granularity in the HCAL
-  excellent linkage between tracker – ECAL – HCAL
-  excellent hermeticity

- 2 photons (pi0 decay)
- in ECAL

## The LC Detector

- LC Detector is general purpose detector, optimised for precision physics

-  excellent tracking
-  excellent calorimetry
-  both located inside magnetic field
-  muon system

- Concepts for a LC detector are under
- development in
- Asia – US – Europe

**Notes:**
list of main goals of LC detector
Layout of a possible LC detector
stress resolution, single particle reconstruction

## The VTX Detector 

- The VTX Detector

-  High precision detector close to the beam pipe (R(min) = 1.5 cm)
-    Several technologies are under discussion
-  CCD based sensors (SLD technology)
-  CMOS based sensors (new development)
-  DEPFET sensors (new development)
-  FAPS
-  HAPS
-  others...

- One of the most challenging
- jobs: H to fermions

- “generic” VTX layout

## CCD Detector R&D

-  principle of operation well proven (SLD VTX detector, others)
-  Goals:
-  excellent resolution: intrinsic resolution,   mechanics, material budget

- Thickness very important:
- intense R&D effort to thin
- sensors in order to minimise
- the material budget.
- goal: 50 um thick sensors
- <1% for complete detector

-  readout speed: column parallel readout,    50MHz clock
-   first successful operation reported this
-   summer at RAL

- Fe 55 peak

- normal

- Column parallel

**Notes:**
Discuss the different technologies: CCD

## MAPS detector R&D

-  MAPS: Monolithic Active Pixel Sensor

-  Each pixel has some readout electronics integrated

-  operationally simpler than CCD
-  no clocking-out of charge: intrinsically radiation harder

**but**

-  little experience as particle detector
-  larger material budget (?)
-  larger power consumption

-  Final readout through chip on the edge of the device
-  Intense R&D to develop working chip since 1999:
-  by now 6th generation of test chips
-  successful operation in test beams

**Notes:**
Different technologies: MAPS?

## DEPFET/ FAPS

-  DEPFET / FAPS: two alternative active pixel schemes:

- DEPFET

- FAPS:
- similar to MAPS
- but more than one
- storage location on the
- pixel

- Both approaches look very interesting, but are at the beginning of development

## Comparison of different options

- Comparison is very difficult at this point: all technologies look promising

- generic
- CCD
- MAPS
- MAPS
- DEPFET
- HAPS

- “Real Estate” comparison (source C. Damerell):

- light blue:
- sensor

- red/ dark blue:
- auxiliary chips

- Tremendous activity, may exciting developments

## Tracking Detector

**TPC as central tracker:**
-  many space points (200)
-  good single point resolution    (O (100 um))
-  reasonable double track resolution    (O (few mm))
-  high redundancy results in excellent    pat rec efficiency

- Most open issues are ones of reconstruction, less of technology

- Two options are being studied:
-  traditional large volume gaseous tracker
-  all SI tracker

**All SI tracker:**
-  few SI layers (strips) behind SI VTX for momentum measurment (“momenter”)
-  rely on VTX for (most) of pattern recognition

**Notes:**
Tracking detector concept and technologies: TPC

## TPC Readout

- "traditional" wire chamber readout:
-  Well understood, stable system
-  "large" granularity
-  Mechanically complicated
-  Systematic effects through            effect

- Alternative solution:
-  Based on micro-pattern (MP) gas detectors
-  GEM/ micromegas
-  Mechanically potentially simpler
-  Less material
-  Less systematic effects (potentially)
-  Not yet proven in large scale projects

- Principle of GEM TPC

- MP detector

- International TPC R&D collaboration: Europe – US - Canada

## Micro Pattern (MP) Gas Detectors

**GEM**:
-  Gas Electron Multiplier
-  amplification in holes in         a Cu clad Kapton sheet
-  usually 2 – 3 stages

**MicroMegas:**
-  high field between   mesh and anode provides amplification
-  single stage

- Intrinsic small length scale of these device allow:
-  good 2-D resolution
-  small systematic effects, in particular in B-fields

- other developments:
- LEM:
- Large Electron Multiplier
- Micro Dot chambers
- etc.

**Notes:**
Challenges of TPC developments for LC, 
'
readout (GEM / Micromegas)

State of R&D

## Performance of MP-TPC

-  several test TPC's exist around the world
-  first performance data are available without and with magnetic field

- resolution vs drift distance, no B field

- drift distance/ cm

- resolution / um

- Investigate
-  GEM properties
-  resolution
-  optimal method to pickup the charge

**Notes:**
More on detector R&D

## Performance in B-Field

-  Most inner detectors are operating in a strong B-field
-  existing detectors up to 4 T
-  planned detectors up to 6T

-  Investigate:
-  operation of MP Detectors in B fields
-  stability? adverse side effects?
-  promise of reduced systematic

- Saclay test magnet

- First results look encouraging
-  stable, predictable operation
-  good behaviour in B-fields

**Notes:**
Performance expectations for tracker: discuss feedback to tracker design

## TPC in other fields

-  ICARUS experiment: neutrino physics detector in Gran Sasso

-  Liquid Argon TPC:
-  2 x 1.5m drift
-  drifttime 1ms

- Recorded some
- rather spectacular
- events:

**Notes:**
Performance expectations for tracker: discuss feedback to tracker design

## All SI tracker option

-  few layers of SI behind the SI VTX detector:
-  based on SLD experience that tracking in VTX is extremely robust
-  use SI detectors to measure the momentum of particles 	(few points, but excellent resolution)
-  SI detectors: “standard” technologies for strip detectors
-  challenges:
-  length of detectors
-  reduce mass of detectors
-  readout

**Notes:**
Performance expectations for tracker: discuss feedback to tracker design

## Calorimeter: ECAL

-  Particle Flow needs:
-  reasonable energy resolution
-  excellent spatial resolution

- SI-W sampling calorimeter

- Typical readout cell size close to Moliere Radius:

- 6.3 mm

- 2.5 mm

- minimise gap:
- 2.5mm standard
- 1.5mm ambitious

- CALICE layout

- US SD layout

- to

- typical parameters:
-  1 x 1 cm2 cells (Moliere Radius Tungsten 0.9cm)
-  O(20 X0) thick with O(40) layers
-  sampling ratio 1:3 to 1:6 depending on design
-  10th of millions of channels

**Notes:**
Role of calorimeter in PFLOW detector

list of requirements
introduction of SI-W sampling ECAL

## Calorimeter: ECAL

- R&D projects:
- CALICE collaboration (Europe – US – Asia)
- US SD detector groups

- develop complete concepts for a
- large SI-W calorimeter:
-  mechanics
-  optimisation
-  readout
-  integration

- prototype assembly of W-plates and
- readout “drawers” from the CALICE
- collaboration

**Notes:**
Technical implementation and challenges of SI-W calorimetery on a large scale

Different approaches (compare EU with US Ansatz)

## SI-W calorimetry

- Cost is major concern for large Si-W Calorimeter

-  driven by SI cost
-  assume 4$/cm2 → 130M$
-  Si costs continue to drop

- readout electronic very important
- significant developments under
- way in EU and US to develop
- integrated, cheap solutions

## Calorimeter: HCAL

- New discussion: Digital HCAL calorimeter
-  record only the cell which are hit
-  no amplitude information
-  small cells: imagining HCAL

- More conventional approach:
- 		      Analogue Tile HCAL
-  record the position and amplitude

- R&D challenges:
- proof of principle
- large scale cheap readout
- algorithm development

- R&D challenges:
- light registration
- system optimisation
- algorithm development

**Notes:**
HCAL: role of HCAL in PFLOW calorimeter

analogue vs digital HCAL

## HCAL: readout technologies

- Analogue Tile HCAL:
-  light registration
-  look at different SI based technologies: have to work in B-field!
-  look at multi-anode photo diodes
-  optimisation of scintillator
-  optimisation of light transport
-  calibration issues

## Non sampling Precision Calorimeter

- MEG experiment at PSI (look for BR(e))

- Optimised for low energy photon detection (50 MeV):
- 	energy
- 	position

-  final detector:
- 	800 l liquid Xenon
- 	~800 PMT’s

- Liquid Xenon Calorimeter

**Notes:**
Technology details on rad hard SI detectors

## Radiation Hardness

-  Radiation hardness of SI sensors is major concern at hadron machines:
- LHC   :       Φ (R=4cm) = 3E15/ cm2

-  LHC:    technology available, but serious radiation damage
-  SLHC: another factor 5-10: need to develop radiation hard detectors

- Start a program of systematic studies to
-  understand radiation damage mechanism
-  do focussed engineering of better materials
-  defect engineering
-  new materials (SiC, Diamond, ...)
-  explore detector operation phase space
-  temperatur
-  forward biasing

**Notes:**
Radiation hardness: 

- requirements from LC
- requirements from SLHC like machine
- RD50

## Si Developments: Rad hard

- radiation hardness for
- gamma irradiation tolerance

- spectacular improvement with
- oxygenated SI

- Gamma radiation: mostly point defects:

- More difficult (and relevant): hadronic particle radiation tolerance

- Recent breakthrough:
- epitaxial SI detectors grown on thin Czochraslki substrates

- For the first time: meet SLHC requirements

- Kramberger et.al, Bucharest – DESY
-  – Hamburg University – CiS Erfurt

- SLHC Fluence

- 100%

- 40%

- 60%

- 80%

- CCE

**Notes:**
Recent developments of rad hard SI detectors

status

new developments

## Conclusion

-  The next generation of HEP experiments poses interesting challenges    for the detector community
-  The LC experiment focus on precision
-  stress single particle reconstruction
-  needs whole new philosophy in the overall detector design and concept
-  the concept of particle flow really pushes the detector

-  Further developments in the hadron community really stress radiation   hardness: significant progress in the last year

-  We have interesting years ahead of us trying to meet these challenges    and trying to have a realistic and workable detector concept ready    in time for a next generation of colliders

**Notes:**
Technology details on rad hard SI detectors

## Challenges

**Where are we?**

**What are the main challenges in the future...???**

- CMS SI wheels

**Notes:**
List R&D challenges 
 - compare to LHC/ Tevatron
 - point out challenges ahead

## The Tracker Concept

-  excellent track and momentum reconstruction
-  outstanding vertexing
-  very efficient tracking (particle flow needs to know about “all” particles)

- traditional Approach:
-  SI VTX detector: high resolution, 4-5 layers
-  large volume medium resolution tracker (e.g. TPC) with many space points
-  some additional detectors (intermediate tracker, endcap) to improve solid  angle coverage etc.

- “All SI” approach
-  SI VTX detector: high resolution, 4-5 layers
-  SI only tracking detector: few layers of good resolution

**Notes:**
Go over the concpt of the tracker in general terms

## The Calorimeter Concept

-  High granularity high segmentation sampling calorimeter as ECAL
-  SI-W ECAL seriously investigated
-  other more traditional options look at combining more standard    ECAL technology (Scintillator tile) with few layers of SI

- typical parameters:
-  1 x 1 cm2 cells (Moliere Radius Tungsten 0.9cm)
-  O(20 X0) thick with O(40) layers
-  sampling ratio 1:3 to 1:6 depending on design
-  10th of millions of channels

-  Highly segmented HCAL
-  analogue Scintillator option
-  “digital” option

- typical parameters:
-  1 x 1 (digital) to 5 x 5 (analogue) cm2 cells
-  O(20 samplings)

- Analogue: record position and energy
- Digital: record position

**Notes:**
concept of the calorimeter in general terms

## VTX R&D Challenges

-  for Linear Collider:
-  readout speed
-  material budget
-  power consumption
-  radiation hardness

-  for hadron machines
-  radiation hardness

- typical LC time structure

- Tesla: 5ms
- NLC:   8us

- TESLA: 337 ns
- NLC:     4ns

- Goal:
- minimise the number of bunches integrated
-  high readout speed: 25-50 Mhz
-  column parallel readout required

- (see later in this talk)

## A typical GEM-TPC

- 3D view of a typical test TPC:
- Berkeley – Orsay – Saclay TPC

- electronics (based on STAR experiment)

- Micro-pattern detector readout plane

- drift volume

- cathode

- 20-40 cm

- up to 1m

## Calorimeter

- Designing a “Particle Flow Calorimeter” stresses the system aspect much more
- than before
- Have to really test the combination of tracker – ECAL – HCAL to judge the system
- performance

- should expect many interesting result
- over the next few years

**Notes:**
Technical challenges for PFLOW HCAL