ATLAS upgrades

Xmass meeting 2008

Current ATLAS Operations ATLAS has been working very well

First beams in Sept recorded successfully by all sub-detectors

Long cosmic runs with the full detector in Oct-NovVery useful for calibration and alignmentVery useful sub-detector synchronization and full system

tests

UCL very visible in ATLAS operations through Atlantis running online at the ATLAS Control Room

(NikosK, SebastianB, ZdenekM, AdamD) L2 track trigger used for selecting good cosmics

(NikosK, ErkcanO, CatrinB, MarkS) SCT operations

(MattW, MartinP)ATLAS Upgrades 2

3

Timelines & SLHC parameters Two phase upgrade in LHC luminosity

Phase I: ~2013: 1034 → 3x1034

Phase II: ~2017: → 1035

Machine parameters at 1035 and some relevant numbers Two possible scenarios

Parameter Scenario A Scenario BBunch crossing 25ns 50ns

rms bunch length 7.55cm(gauss) 11.8cm(flat)

pp events per x-ing 294 403

Distance between pp events in z ~1mm

ATLAS Upgrades

Upgrade plans & UCL involvement

Independent of SLHC scheduleForward physics detectors for ~2012 (UCL)

(MarioC, PeterS, GordonC, MattW, ChrisT, JamesR)

New innermost Pixel Layer for ~2013

For 2017A brand new Tracker (UCL)

(JonB, MatthewW, MattW, MartinP, JanetF)

Upgrades on electronics of all sub-detectorsTrigger-DAQ upgrade (UCL)

(NikosK, MarkL, DaveW, IlijaB, GordonC, MattW)4ATLAS Upgrades

FP220 FP420

Forward detectors: Atlas Forward Physics

• Cold region of LHC• Too far for L1 trigger

FP220

β*=0.5

xL=P’/Pbeam= −ξ

FP420

5ATLAS Upgrades

Forward detectors: 3d silicon for position

Quartz

Two technologies for timing detector

Aim: ~20 ps resolution for first period, 10 ps (3 mm) for the high-lumi running (not there yet)

Much reduced voltage, better rad hardness than planar silicon. Developed by Manchester

Detector technologies for AFP

6ATLAS UpgradesGastof

UCL involvement Software and DAQ convener, member

of management board (MarioC) Integration with Athena, interface with

beam transport code (PeterS) DAQ, link with CTP (GordonC, MattW) Beam Position Monitors (AlexeyL) Participation in test-beams (ChrisT,

JamesR)

7ATLAS Upgrades

8

Physics motivation & Trigger needs for SLHC

Increased sensitivity in the (multi-)TeV regionQuark substructure, new forces, heavy SUSY

Low rates, easy to trigger with high ET threshold triggers

Improved understanding of LHC discoveries, observation of rare processes, EW constraintsHiggs couplings/self-couplings, SUSY propertiesH→, FCNC top decays, multiple gauge boson

production, triple/quartic gauge boson couplings These would lead to objects of similar range of pT as at

the LHC, hence similar trigger thresholds

ATLAS Upgrades

9

ATLAS trigger challenge at SLHC

Essential to retain and enhance our flexibility to tune the trigger to select new physics

Greatest challenge will be L1 Much higher occupancy, so even 100KHz L1A rate will require much

higher readout bandwidth, esp. for the tracker. Alternatives: Rely more on multi-object triggers

Not without consequences: e.g. L1 single muon geom. acceptance ~80%, double muon =(80%)2

Increased probability for trigger objects to come from different pp collisions

Raise pT thresholds (wrt 1034) Studies a few years back, suggested we may have to go up to 60GeV at L1

for single e/ triggers The L1 e/ rates fall much smoother above ~30GeV

Not long before physics suffers; risky if only handle is pT thresholds

Most L1A events are still “garbage” – can we enhance the physics composition of the L1A events, without going to extreme thresholds?

ATLAS Upgrades

ATLAS Upgrades 10

L1Track trigger ideas

Cannot readout the whole tracker at 40MHz Alternatives:

Processing in parallel with L1Calo and L1MuonWould require dedicated tracker layers for triggering or clever ideas

to reduce the amount of data on the detector (or both) Info from L1Calo/Muon/Track combined at CTP

“RoI” based processing, using L1Calo/Muon infoWould require deeper pipelines for all ATLAS sub-systems

(256bx?)Tracker regional readout has to be initiated, and completed in ~2s

“L1.5 track trigger”A hardware-based track trigger making decision in O(10-100)secs

after L1A Would allow perhaps a higher L1A rate (~200KHz?), but can

detectors sustain such readout rate?

None is easier than the others

ATLAS Upgrades 11

RoI based idea: Level Zero Accept L1Muon/Calo reduces the rate from 40MHz to ~500KHz. At 500KHz, it

identifies Region of Interest (RoI) and propagates info to Tracker Cone/tower small near the Calos, opening up near the beamline

RoI mapped to affected modules/supermodules/RODs

Level Zero Trigger (L0A) targeted at individual modules

Would need complete redesign of readout electronics

Latency still an issue

2.0μs Level-0 (current Level-1...) identifies features. Maps to modules. Issues L0A

1.0μs Cable to detector (and back again)

1.0μs Level-0 event readout from tracker

2.0μs Level-1 decision. Issue L1A

0.5μs Cable to detector

6.5μs Total

E

M

Data

Token

MCC

SMC

MCC

SMC

MattW

ATLAS Upgrades 12

A fast pile-up simulation tool

UCL had a standalone software tool to develop the L2 tracking package, IDScan, outside athena Take space points within an RoI from athena, then use

standalone code to tune pattern recognition

Extended this “mini-framework” to do “fast pile-up” Fully simulate signal events (e.g. single muons) and min.

bias events Extract space points (into a root fileA) from signal and (into

a root fileB) from min-bias eventsCould go one (two) step(s) back to clusters(digits)

Mix one signal event from fileA with N events from fileB to produce pile-up

Can mix space points just within an RoI

IlijaB, GordonC