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-Nov Very useful for calibration and alignment Very 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 Upgrades2

3 Timelines & SLHC parameters Two phase upgrade in LHC luminosity  Phase I: ~2013: → 3x10 34  Phase II: ~2017:→10 35 Machine parameters at and some relevant numbers  Two possible scenarios ParameterScenario AScenario B Bunch crossing 25ns50ns rms bunch length 7.55cm(gauss)11.8cm(flat) pp events per x-ing Distance between pp events in z ~1mm ATLAS Upgrades

Upgrade plans & UCL involvement Independent of SLHC schedule  Forward physics detectors for ~2012 (UCL) (MarioC, PeterS, GordonC, MattW, ChrisT, JamesR)  New innermost Pixel Layer for ~2013 For 2017  A brand new Tracker (UCL) (JonB, MatthewW, MattW, MartinP, JanetF)  Upgrades on electronics of all sub-detectors  Trigger-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  *=0.5 x L =P’/P beam =  −  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 Upgrades Gastof

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 region  Quark substructure, new forces, heavy SUSY Low rates, easy to trigger with high E T threshold triggers Improved understanding of LHC discoveries, observation of rare processes, EW constraints  Higgs couplings/self-couplings, SUSY properties  H→ , FCNC top decays, multiple gauge boson production, triple/quartic gauge boson couplings These would lead to objects of similar range of p T 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 p T thresholds (wrt ) 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 p T thresholds  Most L1A events are still “garbage” – can we enhance the physics composition of the L1A events, without going to extreme thresholds? ATLAS Upgrades

10 L1Track trigger ideas Cannot readout the whole tracker at 40MHz Alternatives:  Processing in parallel with L1Calo and L1Muon Would 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 info Would require deeper pipelines for all ATLAS sub-systems (256bx?) Tracker regional readout has to be initiated, and completed in ~2  s  “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 Upgrades11 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 2.0μsLevel-0 (current Level-1...) identifies features. Maps to modules. Issues L0A 1.0μsCable to detector (and back again) 1.0μsLevel-0 event readout from tracker 2.0μsLevel-1 decision. Issue L1A 0.5μsCable to detector 6.5μsTotal E M Data Token MCC SMC MCC SMC MattW

ATLAS Upgrades12 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 events  Could 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