upgrade of the cms tracker for high luminosity operation

09 September 2010

Erik Huemer (HEPHY Vienna)

Upgrade of the CMS Tracker for High Luminosity Operation

OEPG Jahrestagung 2010


2Erik Huemer (HEPHY Vienna)09 September 2010

Outline

• LHC Upgrade to explore Physics Potential

• Challenges for the CMS Tracker• Required Advances in Technology

R&D lines followed by HEPHY– Radiation Tolerant Sensors– Highly Integrated Sensors– pt Track-Trigger Modules

• Summary


3Erik Huemer (HEPHY Vienna)

LHC Upgrade to explore Physics Potential

• Operation until 2020– Design luminosity: L = 1034 cm-2 s-1

• Continue physics programm– Increase in luminosity– ADVANTAGE: more statistics– Also disadvantages

09 September 2010

20102012

20142016

20182020




09 September 2010

• The CMS tracker


1032 1033

1034 1035

• Track densities at different interaction rates

• Disadvantages: – Higher particle background– Higher radiation level– Higher track density




• Increase of radiation level• Higher granularity to resolve dense packing

of tracks• Tracker needs to provide input to the trigger:

- Track-Trigger on pt to enable selection of interesting events

• Amount of material in the tracker has to be minimized: - Interactions in the primary vertex - NOT with tracker material

Challenges for the Tracker




Three R&D Lines

• R&D lines followed by HEPHY1. Radiation Tolerant Sensors

2. Highly Intergrated Sensors

3. pT Track-Trigger Modules

09 September 2010


1. Radiation Tolerant Sensors


• Important operating parameters which change with irradiation- Full Depletion Voltage (VFD)

- Reverse Bias Current (Dark Current)

- Charge Collection Efficiency (CCE)

• Silicon bulk materials and manufacturing processes- Float Zone (FZ) or Czochralski

(CZ/MCZ) silicon- MCZ n-n sensors- FZ n-n sensors- MCZ n-p sensors- FZ n-p sensors- Thickness of the substrate


2. Highly Integrated Sensors


• Now: External pitch-adapter and readout-chips• Future: Integrated pitch-adapter and on-sensor

readout-chip- Reduces material- Higher flexibility- Handles granularity


3. pt Track-Trigger Modules


~200μm

Upper Sensor

Lower Sensor

Pass Fail

~100μm

~1mm

• Fast measurement of momentum (Pt) for trigger decision- Pt through measurement of track

curvature- Track curvature through

determination of contact angle on the tracker

• 2 parallel sensors with some mm space• “Stiff” track with little curvature with high

momentum only Strips hit, only little dislocated High Pt

Upper Sensor

Lower Sensor



pt Track-Trigger Modules

09 September 2010

• Prototype @ CERN- Tested at various angles- Collected 1 TB of data

• Development analysis framework- Different geometry- Different read-out logicFormer analysis

concepts do not work

- Highly object oriented (C++, ROOT)

Quick exchange of single analysis parts



Summary

09 September 2010

• LHC upgrade crucial for future productivity• CMS tracker has to be rebuilt• Three R&D lines- Radiation hard materials under review- Highly integrated sensors

built, tested, partially analysed- pT track-trigger modules

built , tested, will be analysed



Backup Slides

09 September 2010



Luminosity

09 September 2010

L f nN1N2A

Frequency of bunches

Number of bunches Amount of particles in a bunch

Size of interaction area

upgrade of the cms tracker for high luminosity operation

Documents

cms tracker upgrade

high luminosity operationf

high luminosity operation1

high luminosity operation93

outlinelhc upgrade

substrate upgrade

design luminosity

tracker material challenges