February 19th 2009AlbaNova Instrumentation Seminar1 Christian Bohm Instrumentation Physics, SU Upgrading the ATLAS detector Overview Motivation The current

February 19th 2009 AlbaNova Instrumentation Seminar 1

Christian BohmInstrumentation Physics, SU

Upgrading the ATLAS detector

OverviewMotivationThe current design and whyWhy upgradeHowPlanning the short range development


MotivationAccelerator upgrades will increase the luminosity above the design value 1034 cm-2s-1

Phase II Bunch Crossing (BC) rate may change 25->50 ns


Design criteria/considerations for an ATLAS type detector • Higher energies to study new phenomena

• Large luminosity to study rare events – many events to reach 5




• Tracker near beam pipe to determine the source position• Magnet around beam pipe for momentum information

• Large E/M calorimeter to stop and measure energy of electrons and photons – not too large to stop hadrons as well




• Tracker near beam pipe to determine the source position• Magnet around beam pipe for momentum information

• Large E/M calorimeter to stop and measure energy of electrons and photons – not too large to stop hadrons as well

• Large hadron calorimeter to stop and measure energy of hadrons• Minimize matter in front of calorimeters to improve resolution

• Should the magnet be inside or outside the calorimeters• Large muon detector with strong magnetic field to measure muon energies with high precision.


Design criteria/considerations for the on-detector electronics

Radian tolerance and reliability main problems

Long design cycles -> problems with obsolescence

Paradigm shifts during long development processes



Radiation tolerance and reliability main problems



• Radiation tolerance achievable – bandwidth expensiveOn-detector logic and memories – transfer only if necessary• Radiation tolerance expensive – bandwidth achievable

Minimize on-detector electronics – transfer as soon as possible• Radiation tolerance achievable – bandwidth achievable

On-detector logic OK but minimize for reliability – protect for transient errors



Radian tolerance and reliability main problems



• Radiation tolerance achievable – bandwidth expensiveOn-detector logic and memories – transfer only if necessary• Radiation tolerance expensive – bandwidth achievable

Minimize on-detector electronics – transfer as soon as possible• Radiation tolerance achievable – bandwidth achievable

On-detector logic OK but minimize for reliability – protect for transient errors

ASICs -> FPGAs (sometimes even on-detector)

Another change:During phase 0 LHC projects were often driving technology development

Now it is telecom


Current design ATLAS


Current design ATLAS data Flow

40M

Hz

LHC physics looks for rareevents – 1 in 1014

High event rates andHigh selectivity

new data every 25 ns

About 100 million channels



40

M H

z

1 event in 400


Since all data must be stored while waiting for the L1 decision the L1 processing must be quick – <2.5ns

Data from entire detector but with low spatial resolution and reduced dynamic range from calorimeters and muon detector


75

k

Hz

The high granularity datais merged into roughly 64x64 trigger towers each.1x.1 in and where = log

Design requirement



2 k

Hz

40

M H

z



1 event in 100

Data from ROIs with high spatial resolution and full dynamic range from all subdetectors 7

5

kH

z




20

0 H

z2

kH

z7

5

kH

z4

0M

Hz


1 event in 100

Entire detector with high spatial resolution and full dynamic range from all subdetectors

To Grid


Current design L1 Trigger algorithms

Look for isolated particles

e/ /had

Simplistically regard the L1 processor as consisting of 4096

parallel processors – one for each .1x.1

trigger tower

Count the number different threshold combinations in the central trigger

processor (CTP)


Current design L1 Trigger algorithms

Look for JETs

0.4 x 0.4

0.6 x 0.6

0.8 x 0.8

ROI Identification Identify 0.4 x 0.4 windows

that are local maxima Jet Identification

Apply thresholds to 0.4, 0.6, or 0.8 clusters around the local maxima

8 Jet definitions available, each with selectable energy threshold and cluster size

Simplistically regard the L1 processor as consisting of 1024

parallel processors – one for each .2x.2

trigger tower

Count the number different threshold combinations in the CTP


The x3 increased luminosity will lead to increased radiation levels and more pile-up

Phase I upgrade, 6 months

The inner layer of the inner detector must be replaced due to radiation damage


The phase I upgrade

Since the innermost layer cannot be replaced a new layer (IBL) is insertedcloser to the beam pipe -> smaller beam pipe

Another detector part that may need replacement is the FCAL electronics

Increased luminosity ->more events

Unrealistic to change level 2 rate ->Improve L1 rejection

One way is to increase thresholds

Another way is to improve L1 trigger by bringingsome L2 processing down to

L1


The phase I upgrade

Topological algorithms can be introduced in the L1 calorimeter trigger

Use the ROI position information

Takes additional time to determine in L1Calo and

to evaluate in the L1 CTP

The latency margin seem to suffice

The main part of L1Calo stays

inserting a new layer between L1Calo and CTP

and a new CTP


The x10 increased luminosity will lead to more increased radiation levels and still worse pile-up

Phase II upgrade, 1.5 years

All the on detector electronics has reached its designed life

time


Phase II upgrade

Completely new inner detectorThe rest of the detector more or less OK

New calorimeter on-detector and off-detector electronics

Increased luminosity ->new electronicsIncreased luminosity ->more events->more logic

Level 2 rate fixed?!

Completely new L1 trigger


Phase II upgrade

Increased luminosity -> increased L1 trigger efficiency -> more information to L1

High granularity, depth segmented info from calorimeters

Higher thresholds not enoughmore info from muon detector?

or a Track trigger?Simulations needed


Calorimeter ideas

Full readout

Minimize on-detector electronics

Massive data transfers

Preprocessor delivers tower info with flagse.g. high granularity or depth flags


Track trigger ideas

High Pt trigger

Supply track info on demand -> much longer latencies

L 1.5 track trigger

Very challenging


Practical planning Less work than phase 0

FinancingLong lead times

Radiation tolerance testingSIMULATIONS NEEDED

Experience from running ATLAS (radiation damage)Coordination with machine, CMS,…

Organize installationOrganizational structures: USGs, UPOs, ATLAS weeks, meetings,

meetings,….

SchedulePhase I (2013) and phase II (2017) – mostly controlled by machine

development which is not primarily affected by the delay,the schedule may thus not slide with the startup delay.

Atlas upgrade LoI 2009, IBL TDR 2009,upgrade TP 2010 (maybe with options),

upgrade TDR 2011

We are already late compared to phase 0!

Documents

February 19th 2009AlbaNova Instrumentation Seminar1 Christian Bohm Instrumentation Physics, SU Upgrading the ATLAS detector Overview Motivation The current