cms upgrade requirements and upgrade plans

CMS Upgrade Requirements and Upgrade Plans

Hans-Christian Kästli, PSI

11.6.2008

CHIPP Workshop on Detector R&D

CMS upgrade plans 11.6.2008 2/32

Contents

• Introduction & Motivation

• Part I: Subsystems

– Trigger

– Tracker

– Calorimeters & Muon system

– Common Projects

• Part II: Phase I barrel pixel upgrade

Contains material from J. Nash, G. Hall, R. Horisberger


A realistic (?) upgrade scenario

[J. Nash]


Requirements from Physics

Performance @SLHC need to be at least as good as now

•Especially true for forward jet tagging and b-tagging

•pT resolution ok as is•IP resolution ok, but need to be kept at this level at SLHC (radiation damage reduces tracker resolution)


Organisation


The CMS Experiment

TRIGGER


Triggers

Level 1 trigger consists mainly of:• Muon triggers from individual stations (local)• Calorimeter triggers

• e/isolated ECAL trigger towers, no HCAL energy• : isolated ECAL + HCAL trigger tower • jets: ECAL + HCAL energy in cone

Higher level trigger:• Combine local muon to global muons• Combine muon tracks with tracks from inner tracker to improve pT resolution• Correlate calorimeter trigger with tracker information (e//QCD

discrimination )

At SLHC most of these triggers at level 1 will exceed any realistic trigger rate. There is a severe trigger problem for CMS at L=1035cm-2s-1 !


Level 1 Trigger at SLHC

(MH

z)

and jet rates

Problem: isolation of calorimeter towersSame problem for electron trigge

Muon trigger rates

Problem: insufficient pT resolution from muon system

Level 1 trigger hasno discriminationfor pT>~20GeV/c


Level 1 Trigger at SLHC

Guided from high level trigger at LHC:

•Muon system needs tracking information on level 1•Need trigger layers/trigger information from tracker•pT measurement-> outer radius•Need correlation between muon and tracker

•Electron trigger needs tracking information on level 1•Z-vertex information for cluster-track matching• rejection -> innermost tracking layers (conversion)•Need correlation between calos and tracker

• trigger needs tracking information on level 1•Jet rejection -> complete tracking•Need correlation between calos and tracker

Tracking triggers absolutely needed But: cannot do everything. Need priorities and/or compromisesVery challenging, only vage ideas around

TRACKER


Tracking @ LHC

CMS has an all-Si tracker with– 3 pixel barrel layers– 10 strip barrel layers (4 stereo)– 2 pixel endcap disks– 3+9 strip enddisks (2+2 stereo)

The expected performance is excellent as indicated on the right

pT and transvers impact parameter resolution

track reconstruction of hadrons in b-jets

BUT: it is heavy!This shows up in the photon conversion rate, in the track reconstruction efficiency for pions and in the track fake rateWill become a problem in SLHC


Material Budget

In very central region ~0.3 radiation lengthA lot of materials from cables in forward region! In future difficult to bring the power in

Support structure contributes a lot, but cannot gain much in inner partExcept: fewer layers less material, less power, less costs

Why are there so many?• Serious concern about pattern recogni-

tion with so few points (unprecedented design and environment)

• Probably can be relaxed (although still no full simulation of loopers… and we haven’t seen data yet!!)


Going to SLHC

25 ns bunch structure


Tracking with 500 min bias events• Study of current CMS tracker for Heavy Ion

events• Track density very similar to 50ns running

– dnch/d/crossing ≈ 3000 – Tracker occupancy very high– Need more pixel layers/shorter strips

• Tracking is possible (thanks to pixel!)– When tracks are found they are well measured– Efficiency and fake rate suffer– CPU Intensive

• algorithmic efficiencyo fake rate

Momentum Resolution

Impact Parameter Resolution

Pixel layersPixel layers

Inner layers of strips reach 30% occupancy on every xing!

Inner layers of strips reach 30% occupancy on every xing!


Key Areas for Tracker R&D

• Reducing and delivering power at lower voltage…

• DC-DC conversion, serial powering

• …and removing it, with limited material

• CO2 cooling, other cooling schemes

• Ensuring sufficiently rad hard sensors are available

• and establishing the manufacturing capability with industry

• A new readout & control system using modern technologies

• radiation hardness may be a minor point this time

• Developing components to build one or more layers which can contribute to the L1 trigger

• these layers must also be light and power-efficient

• Designing a tracker layout from these which will meet the physics objectives (last, but by no means least…)


Tracker related R&D Projects

Proposal title Contact Date StatusCMS ref

Letter of intent for Research and Development for CMS tracker in SLHC era R Demina 14.9.06 Approved 06.01

Study of suitability of magnetic Czochralski silicon for the SLHC CMS strip trackerP Luukka, J Härkönen, R

Demina, L Spiegel31.10.07 Approved 07.06

R&D on Novel Powering Schemes for the SLHC CMS Tracker L Feld 3.10.07 Approved 07.01

Proposal for possible replacement of Inner Pixel Layers with aims for an SLHC upgrade A Bean 31.10.07 Approved 07.07

R&D in preparation for an upgrade of CMS for the Super-LHC by UK groups G Hall 31.10.07 Approved 07.08

The Versatile Link Common Project F Vasey, J Troska 11.07 Received 07.12

3D detectors for inner pixel layers D Bortoletto, S Kwan 12.07 Received 07.13

Proposal for US CMS Pixel Mechanics R&D at Purdue and Fermilab in FY08 D Bortoletto, S Kwan 12.07 Received 07.15

R&D for Thin Single-Sided Sensors with HPK M Mannelli 7.2.08 Received 08.01

An R&D project to develop materials, technologies and simulations for silicon sensor modules at intermediate to large radii of a new CMS tracker for SLHC

F Hartmann, D Eckstein 6.3.08 Received 08.02

Development of pixel and micro-strip sensors on radiation tolerant substrates for the tracker upgrade at SLHC

M de Palma

9.4.08 Received


Working Group Organisation

* PSI

Sensors

G BollaA Messineo

Triggeringdeveloping

Simulations& SoftwareH CheungA Tricomi

PowerK Kleinn tbd

Readout system

H-C Kästli*K Gill

Material budgetEngineering, Services

S König*A Onnela

Steering GroupWorking Group convenors

G Hall D Bortoletto R Horisberger* M de PalmaP Sharp M Mannelli GM Bilei

• These goals motivated the R&D structure

• active for 12-18 months


Barrel Strawman Designs

SuperlayerSuperlayer

Strawman A Geometry:Strawman A Geometry:Perturbation of current tracking systemPerturbation of current tracking system4 Inner pixel layers, 2 strixel + 2 short 4 Inner pixel layers, 2 strixel + 2 short strip layers (TIB), 2-strixel + 4 short strip strip layers (TIB), 2-strixel + 4 short strip layers (TOB)layers (TOB)

Short stripsShort strips

Strixel layers, Strixel layers, could be doubletscould be doublets

Pixel layersPixel layers

Mini-strip or Pixel doubletsMini-strip or Pixel doublets

Strawman B Geometry:Strawman B Geometry:Design radically different from current Design radically different from current trackertrackerSuper-layers, each with two doublet Super-layers, each with two doublet layers (integrated tracking/ triggering layers (integrated tracking/ triggering layers); 3 inner Pixel layerslayers); 3 inner Pixel layers


Strawman B: triggering + local data reduction

α

• 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– Keep only vectors corresponding to high pT

tracks

• Stacks of 2 sensor pairs, at ~ cm distance

– Redundancy

– Track stub provides higher resolution local pT measurement

Two level data reduction

But: Material budget? How light can we build this? Power?

Triggering needed, but mustn’t geopardize tracking

CALORIMETERS&

Muon System

Hadron Calorimeter


• Forward calo may be blocked by potential changes to the interaction region. This has a direct impact mainly in the case of looking for WW scattering

• Upgrade proposal for new trigger/DAQ readout– New SiPM with higher gain/less noise– Allows to

- add timing information- make longitudinal segmentation to reduce

sensitivity to min bias

• Both Calorimeters suffer degraded resolution at SLHC– affects electron ID, Jet resolutions

Electromagnetic Calorimeter


• ECAL– Crystal calorimeter electronics designed to operate in SLHC conditions– VPT in Endcap and Endcap crystals themselves may darken at SLHC

• Very difficult to replace– At SLHC, per Trigger Tower, per crossing, 12 expected ( rate in ECAL ~2.4 MHz/cm2), <PT> ~3 GeV No empty ECAL

towers– The readout of every crystal is technically possible, by increasing the readout rate from 0.8 Gbits/s to 14 Gbits/s for 25

crystals.

full calorimeter information could be used in the level 1 trigger decision Proposal by R. Rusack, Proposal for ECAL R&D (Phase II), DPG 27-FEB-08

• Physics benefits arguable but definitely not proven• Major effort to remove the supermodules, remove the LV cables and replace the front-end boards, check and re-install.• Requires un-cabling of the tracker to remove the ECAL supermodules• Radiation levels for all this work

Muon System


• System front end electronics look fairly robust at SLHC• Cathode Strip Chambers/RPC Forward • Drift Tubes /RPC Barrel

• Trigger electronics for the muon systems would most likely need to be replaced/updated

– Some Electronics is “less” radiation hard (FPGA)

– Coping with higher rate/different bunch crossing frequency

– May have to limit coverage in ( > 2) due to radiation splash

• This effect will be known better after first data taking, potential additional cost of chamber replacement

Infrastructure Modifications: Yoke


Supplement YE4 wall with borated polythene

Improve shielding of HF PMT’s possibility of increased YE1-YE2

separation to insert another detector layer?

Reinforced Shielding inside forward muons:

up to ~2 automatically implies replacement

of inner CSC, RPC

COMMON PROJECTS

Common Projects


There are many common R&D topics which must be pursued by ATLAS and CMSA Joint meeting was held last year to discuss possible joint R&D

•ACES meeting - http://aces.web.cern.ch/aces/•Will repeat later this year

Topics include•Link Technology

•Versatile link project (CERN): rad hard physical network layer for optical links•GBTproject (CERN): gigabit optical link for data/control/trigger

•ASIC technology •130nm technology

•Power distribution•Funding from EU•Rad hard DC-DC converter (CERN)•Small contribution from PSI: on-chip DC-DC conversion

•Cooling•Tests on CO2 cooling hosted by CERN cryolab

•Radiation/shielding issues

Part II

Barrel Pixel System for Phase I


Phase 1 Tracker Upgrade

• In 2013 need to replace > 50% of pixel barrel modules & probably optical-links due to radiation damage. Pixel module fluence limit = 6x1014 cm-2 (TDR)

• Barrel mechanics constructed for quick insertion/deinstallation • Radiation damage & activation probably require a complete rebuild of barrel pixel• Services (cables, fibres and cooling tubes) will have to be re-used. No replacements,

no additions.• Rest of tracker will be unchanged (long shutdown would be needed to access strip

tracker)

PSI/UNIZ/(ETHZ) are interested in building a new barrel pixel detector for the phase I upgrade

Several possible scenarios presented by Roland Horisberger:http://indico.cern.ch/conferenceDisplay.py?confId=28746

No official proposal yet.

http://indico.cern.ch/conferenceDisplay.py?confId=28746









Options for Barrel Pixel


Option

0

1

2

3

4

5

Cooling

C6F14

C6F14

CO2

CO2

CO2

CO2

Readout

analog 40MHz

analog 40MHz

analog 40MHz

analog 40MHz-tw-pairs

digital 320MHz-tw-pairs

digital 640 MHz-tw-pairs

Pixel ROC

PSI46 as now

2x buffers

2x buffers

2x buffers

2xbuffer, ADC160MHz serial

2xbuffer, ADC160MHz serial

Layer/Radii

4, 7, 11cm

4, 7, 11cm

4, 7, 11cm

4, 7, 11cm

4, 7, 11cm

4, 7, 11, 16cm

Power

as now

as now

as now

as now

as now

DC-DCnew PS

Comment

as 2008

Data loss reduction

Large gain in material budget

Simplifies module design

Test structures designed

Uunlikely for 2013(services)

Option 0: Simple Replacement


Pro:

•Data taking and physics output of CMS experiment is not disturbed

•Pixel detector is well calibrated, aligned, efficiencies are studied, algorithms are stable

•No big brainpower has to be drafted for rebuild focus on physics output of CMS

•Time schedule and costs are likely under control

Con:

•Rebuild detector conceived in 1997

•Detector designed for Luminosity of 1x1034 and will develop substantial inefficiency for 4cm layer at 2x1034

•We did a reasonable job in material budget (1.92%/Layer at =0) but could be improved, especially in eta region 1.4-2.3

•Present pixel needs considerable algorithmic know how to deal with gain variability of optical chain and event decoding

Option 2: CO2 cooling


• Use bi-phase CO2 cooling and benefit from reduced material budget !

• allows long cooling loops (~2-3m) with very small diameter pipes (~1mm) for thermal loads of ~100 W

• Present C6F14 monophase has parallel cooling pipes with manifold and large diameter silicon hoses for feed and drain in front of FPIX tracking region.

• New CO2 allows serialized pipes without pressure drop problems and therefore reduces resident cooling liquid by large factor.

• Density of liquid CO2 is ~ 1.03 g/cm3 compared to 1.76 g/cm3 of C6F14

• Needs considerable engineering support from CERN for CO2 cooling plant.

C6F14cooling

CO2cooling

Material distribution budget for 3 barrel layers

Option 2: Weight of one half barrel


BPIX now BPIX CO2 cooling

Empty mechanics : 1103 g 550 g ~94g , 1.5mm pipes

384 Module 2.27 g each 872 g same

384 Signal cable (21.7mg/cm) 167g same

384 Power cable (10.6 mg/cm) 82g same

384 Power plug (42 mg/plug) 16g same

32 Print (15.61g each) with red power cable 499g same

Cooling (C6F14) in tubes, manifolds & pipes 810 g 83 g 1.45mm pipes

2x1024mm Silicon tube + C6F14 in side 372g 5 g serial piping

Total 3921g 2274 g

Average material budget gain 1.72 , but in region =1.4 – 2.3 much more

Option 3: Replacing Kapton signal cables


• use -twisted pairs 2x125m of enameled Copper Cladded Aluminum (CCA) wires could provide a viable signal cable alternative for Kapton cables

• Why?• Kapton cable can only bend in one plane. • O(1000) modules result in very complex, expensive, laboursome endflange

prints, which contribute considerable in material budget in range ~1.6• Kapton cable length limited to < 40cm & expensive• Each 300m plug is small & light, but ~800 soldered onto PCB with 21

traces in the sensitive tracking region are definitely not light !• Benefit?

• modules with long pigtail cables (~1.2m) allow transmission of analog output signals without impedance breaks.

• More freedom in bending cables in all directions• Omit endflange print no soldering, simpler mechanics endflange, no PCB,

no strong mechanics supports of PCB for plugging forces • Can move optical links with auxiliary chips further out (~50cm) to high -

range and remove material budget from sensitive tracking region

Option 3: Weight of one half barrel


BPIX now BPIX CO2 cooling

Empty mechanics : 1103 g 550 g ~94g , 1.5mm pipes

384 Module 2.27 g each 872 g same

384 Signal cable (21.7mg/cm) 167g 14g 4x(2x125)

CCA

384 Power cable (10.6 mg/cm) 82g 68g 5x250 CCA

384 Power plug (42 mg/plug) 16g 0g

32 Print (15.61g each) with red power cable 499g 32g radial cables

Cooling (C6F14) in tubes, manifolds & pipes 810 g 83 g 1.45mm pipes

2x1024mm Silicon tube + C6F14 in side 372g 5 g serial piping

Total 3921g 1624 gLarge material budget gain for =1.4 – 2.3 forward impact parameter

gain 2.4x

Summary and Conclusions


•Luminosity will increase gradually•Due to radiation damage pixel needs to be replaced in 2013 anyway•Aim for pixel re-design in Phase I

Several options sketched •with large gain in material budget•possible within reasonable time scale/costs

•Phase II upgrade:• Calo + muon system: minor upgrades needed• Trigger: need tracking information on level 1• Tracker: completely new tracker needed to cope with high data rates. Extremely

challenging project:•Increasing channel number•Must reduce power•Must provide trigger information•Should reduce material budget•Have to reuse present services

•Time is short. Schedule has to be harmonized with ATLAS !

Backup slides

May 2008 G Hall 38Geoff Hall SLHC UG WG June 200738

Constraints on LoI & TDR submission dates come from several places..

Input to LoI preparation

Input to TDR preparation

NB “Remaining R&D” shows time left after “known” within R&D phase

Examination will show this is an aggressive schedule

When is t = 0?

Examination will show this is an aggressive schedule

When is t = 0?

Timescales

• Plan still seems a reasonable estimate, given 1 year shift

• Examples of a few predecessor activities

– Prototyping of readout ASICs, including any needed for triggering

– Development of sFEC, control system & sFED

– Prototype sensors with major manufacturers

– Provisional mechanical support design

– Development and evaluation of prototype modules

– Definition of cooling scheme

– Definition and proof of power distribution scheme

– Development of cost model, TDR cost estimate

• including establishing funding, preliminary negotiations with vendors

– ~ 6 months for TDR preparations and writing

• Submission of Phase II TDR ~ end 2012

– With approval and launch of approved construction project ~mid-2013

39

Possible LoI 2010& Phase I TDR?

May 2008 G Hall

BPIX Options for 2013 replacement/upgrade

Option

0

1

2

3

4

5

<X0 gain>

1

1

1.7

2.4

3.1

~1.6

Costs

4.5 MCHF

5.0 MCHF

5.4 MCHF

5.4 MCHF

5.9 MCHF

~9.8 MCHF+0.4 MCHF

Weight

3921 g

3921 g

2274 g

1624 g

1267 g

~ 2400 gestimate

Start Date

Aug 10

Nov 09

Nov 09

Nov 09

Dec 08

not possiblefor 2013

Comments

ROC wafers exist

new ROC wafers

0.4 MCHF for CO2 plant

- - -

new ROC & TBM & HDImod. pxFED & pxFEC

DC-DC convertersnew LV Power Supplies

cms upgrade requirements and upgrade plans

Documents

trigger cms upgrade

tracker cms upgrade

nash cms upgrade plans

gevc cms upgrade plans

organisation cms upgrade

horisberger cms upgrade

cms upgrade requirements

detector rd cms upgrade