LHC detector upgradesSteinar STAPNES1 Physics motivation for increased luminosity  Some examples of the physics potential Machine Upgrade  Detector interface issues and timescales LHC detector changes  ID changes, charges in the forward area, radiation effects, what can be kept Ongoing activities and organisation Conclusions LHC Detector Upgrades Overview

LHC detector upgradesSteinar STAPNES2 Physics motivation Fairly detailed studies made Now also at: Eur. Phys. J, C 39, (2005) Detector performance, pile-up included All results are preliminary Assumption :  L dt = 1000 fb -1 per experiment per year of running Standard Model: multiple Gauge Bosons, top rare decays, … Standard Model: multiple Gauge Bosons, top rare decays, … Higgs : rare decays, couplings, self-couplings, heavy Higgs MSSM, … Higgs : rare decays, couplings, self-couplings, heavy Higgs MSSM, … Beyond SM: strong EWSB, SUSY, Z’, compositeness, …. Beyond SM: strong EWSB, SUSY, Z’, compositeness, …. More details here

LHC detector upgradesSteinar STAPNES3 Physics motivation Main scenario used LHC SLHC  s 14 TeV 14 TeV L Bunch spacing  t 25 ns 12.5 ns *  pp (inelastic) ~ 80 mb ~ 80 mb N. interactions/x-ing ~ 20 ~ 100 (N=L  pp  t) dN ch /d  per x-ing ~ 150 ~ 750 charg. particles ~ 450 MeV ~ 450 MeV Tracker occupancy 1 5/10 Pile-up noise in calo 1 ~3 Dose central region Gy/year R=25 cm

LHC detector upgradesSteinar STAPNES4 Physics motivation Expected detector performance

LHC detector upgradesSteinar STAPNES5 Physics motivation Examples MSSM Higgs sector : h, H, A, H  In the green region only SM-like h observable at LHC (300 fb -1 /exp), unless A, H, H   SUSY particles  LHC can miss part of MSSM Higgs sector For m A < 600 GeV, the LC can demonstrate indirectly (i.e. through precision measurements of h properties) SUSY-type Higgs sector at 95%C.L. --> this region is ~ fully covered at SLHC Red and blue lines: SLHC extensions for 3000 fb -1 /exp. Regions where  1 heavy Higgs can be discovered at 5  or excluded at 95% C.L. at SLHC m h < 130 GeV m A  m H  m H 

LHC detector upgradesSteinar STAPNES6 Physics motivation Examples

LHC detector upgradesSteinar STAPNES7 Physics motivation Examples

LHC detector upgradesSteinar STAPNES8 Physics motivation Examples Triple Gauge Bosons WW , Z Probe non-Abelian structure of SU (2) and sensitive to New Physics ,  k  from W   l  Z,  k Z, g 1 Z from W Z  l ll l =e,  l =  (to be conservative..) -couplings increase as ~ s  constrained by  tot, high-p T tails k-couplings : softer energy dependence  constrained mainly by angular distributions  Z kZkZ Z 14 TeV 100 fb TeV 100 fb TeV 1000 fb TeV 1000 fb -1 95% C.L. constraints for 1 experiment from fits to  tot, p T , p T Z - SLHC sensitivity at the level of SM radiative corrections - only high-p T muons and photons used (assuming trackers not replaced)

LHC detector upgradesSteinar STAPNES9 Physics motivation Examples

LHC detector upgradesSteinar STAPNES10 Physics motivation Examples

LHC detector upgradesSteinar STAPNES11 Physics motivation Summary

LHC detector upgradesSteinar STAPNES12 Physics motivation Some conclusions of these studies Significantly increased physics reach in practically all typical LHC physics channels. It is not clear today (need LHC first results and operation experience in all areas – for machine and detectors – to make more qualified statements) if these improvements are absolutely crucial for new physics, or rather if they represent (gradually) better measurements and better exploitation of the LHC energy domain. However, in either case upgrading the LHC seems very attractive and an obvious next step to plan for. Physics summary: The luminosity will increase as function of time at LHC, we will need to upgrade the detectors to take advantage of this. Some parts of the detector systems might have performance problems or operational problems, and will therefore require interventions and improvements faster than foreseen today. We have an impressive expertise about the construction and we know today how we would like to improve the detectors - and we will soon have some human resources available to study practical improvements. The pragmatic view:

LHC detector upgradesSteinar STAPNES13 LHC upgrade Machine/detector interface The most relevant parameters for the detectors from previous talk (Ruggiero):  BCO interval: 25ns, 15ns, 12.5ns, 10ns (or 75ns)  Forward area/beampipe : Would like to move the closest machine element towards the IP  Timescales : see previous talk – assume 2014±2 years  Increased radiation levels (and resulting activation) : Need to improve shielding, moderators, access procedures, and safety in general – important constraint for any change considered Driven by this plot, but also by lifetime of IR quads 700 fb -1

LHC detector upgradesSteinar STAPNES14 LHC detector changes The critical areas  To take advantage of a luminosity increase the detector performance of ATLAS and CMS have to be kept – i.e tracking, b-tagging, vertexing, energy and momentum measurements  The detector changes have to be ”reasonable”, one cannot replace the entire detectors for reasons of cost and time. One would like to keep as much as possible of the existing large items (calorimeters, muon systems, magnets, cooling, gas, cables, pipes, support structures, movement systems, cryogenic systems, etc). Based on the physics considerations and machine constraints - what to upgrade:  The Inner Detectors will need to be replaced (expected lifetime of 10 years at – due to sensor damage and damage of electronics elements).  Changes will be needed in the forward area (in order to move machine elements closer to the detectors). These changes affects shielding and beampipe, and might also conflict with existing calorimeters or magnets.  CMS in particular believe that for keeping an efficient muon trigger ID tracking information should be used at level one.  Radiation and activation levels increase, and ageing and space-charge effects of calorimeters and muon chambers need to be studies in more detail, the goal is clearly to change as little as possible  Depending on the chosen BCO frequency - the impact on the existing electronics can change significantly.  Trigger and DAQ need to be upgraded (due to lifetime of many parts this will probably happen earlier for parts of the system – and higher luminosity can be anticipated in these changes) So the most clear modifications needed are:

LHC detector upgradesSteinar STAPNES15 LHC detector changes Radiation levels at SLHC

LHC detector upgradesSteinar STAPNES16 LHC detector changes ID changes In the current ATLAS/CMS trackers a factor ten luminosity increase would imply that the detectors die within months, and/or become useless due to increased occupancy creating problems for the tracking, and/or going beyond the acceptable readout rates. This applies to both PIXEL and Strip systems in ATLAS and CMS. The TRT in ATLAS will have an occupancy which approaches 100% and cannot be used. An other way of saying this is that the current technologies, with important new developments could work at a factor 3 higher radius. So we are looking at a full silicon tracker (the best current example is CMS) TRT endcap A+B TRT endcap C TRT barrel SCT barrel SCT endcap Pixels

LHC detector upgradesSteinar STAPNES17 ID layout and granularity SLHC ID layout example 3 Pixel Layers 14,32,48  Sectors 5,12,18 R Location 4 Short strip layers 22,32,40,48  Sectors 27,38,49,60 R Location 2 Long Strip layers 32,40  Sectors 75,95 R Location Moderator

LHC detector upgradesSteinar STAPNES18 With existing ATLAS tracker  Track reconstruction efficiency inside high-pT jets (from 400 GeV Higgs decays) for different luminosities L=0, 10 34, 5×10 34,  Rate of fake tracks Clearly not good enough but it does not fall over … LHC detector upgrade Pattern recognition at SLHC

LHC detector upgradesSteinar STAPNES19 10,000e 5000e Sensors: main issues are :  Reverse currents rise.  Trapping increases.  Bulk type inverts to effectively p-type – depletion voltage increase. Consider to use p type bulk material to operate more effectively under- depleted, collection electrons (less trapping)  For example: A conservative target for SLHC short strips would be survival of ~2 ×10 15 cm-2 1MeV neutron equivalent, with S/N > 10  For PIXEL area more difficult, replaceable or 3D type (see RD50 studies for cm-2 1MeV neutron equivalent sensors) Both CMS and ATLAS have very good experience with sensor production and quality in current experiments For the innermost layer(s) special measures or replaceable system need to be considered – most significant R&D area LHC detector upgrade Elements of new IDs ? Electronics in DSM work well, parts already tested to 100 MRad (and more but not powered), ie 0.13um or 0.09um processes can do the job (CMOS or SiGe) - and costs are quite reasonable  The lowest layers need special attention – even more true for sensors (make replaceable?)  Yield/costs; ATLAS PIXEL chip has around 80% yield, production costs promising (but prototyping costs large – one iteration assumed in plot on the left) Important R&D area: Very significant improvements in power distribution (serial powering or rad hard DC/DC) needed

LHC detector upgradesSteinar STAPNES20 LHC detector upgrade ID production clusters and timescales  CMS assembly with identical systems at 7 sites to produce ~15K modules.  Aim to complete modules in 2 years  Nevertheless; to complete the R&D, build pre-series, complete the module production and integrate, all ready by 2014 is challenging  Costs will similar (or likely significantly larger) than the current trackers (these are MCHF) Example of robotics & large scale organizational approach:

LHC detector upgradesSteinar STAPNES21 LHC detector changes Activation and move of TAS/QUAD  Moving the last element closer to the IP clashes with shielding/toroids and CALO elements (impact depending on radial size of machine elements in question and their position)  Activation levels already critical, would help to increase Be part of beam-pipe, generally any machine element in this region likely to increase backgrounds  Generally speaking, a careful common optimisation of the forward regions of the detectors is needed wrt: Shielding/activation, Opening scenario, Beam-pipe changes, Magnetic fields Maintenance operations must be designed for maximum of 5 mSv/year total dose (safety factor).

LHC detector upgradesSteinar STAPNES22 LHC detector changes Initial measurements/background levels An early key measurement at LHC is a verification of the radiation and activation levels (in all parts):  Will impact the lifetime of our hardware  Determines the access restrictions, at LHC and SLHC  To calibrate our fluence models  To verify (or falsify) our detector material modeling of “active” materials  Will determine margins for luminosity increases in the muon region  Will determine margins for a number of items sitting in the cavern, COTS, regulation elements, etc.  …. and probably more So only after these measurements are made we can make real judgments about where and when we will hit critical limits for increased luminosity See example of simulation of neutron background – used now to optimise shielding and moderators, and beampipe layout (neutrons in kHz/cm 2 )

LHC detector upgradesSteinar STAPNES23 LHC detector changes BCO frequency changes The ID electronics can be redesigned to any new BCO (10,12.5,15, 25 or 75 ns) Changing the bunch crossing time from 25 ns to 12.5 ns can be done for calorimeters and muon chambers, however not all signal filtering can be optimised for 12.5 ns and BC ID might not be possible at trigger level for all trigger types  Nevertheless, 12.5 ns probably largely ok, BC ID (partly) possible, but S/N not fully optimised in all cases  It will be question of costs/performance to determine what to change … Changing to 10 or 15 ns would require changes in electronics HW and intervention at FE crate level (on detector)  These consequences only partly understood but they imply a very significant amount of work and costs Trigger/DAQ will need to be changed (but many parts are already clocked faster than 40 MHz) and in particular lvl 1 parts need to be (partly) rebuilt 75 ns generally ok instrumentally but pile-up will degrade performance

LHC detector upgradesSteinar STAPNES24  Tracker input to L1 trigger  Proposed boundary conditions  Rebuild L1 processors  Maintain 100kHz limit for L1 trigger  Increase latency to 6.4µs  ECAL digital pipeline holds 40MHz  Assume clock speed is 80MHz  or some acceptable f agreed with machine Muon L1 Trigger rate at L = cm -2 s -1 Note limited rejection power (slope) without tracker information LHC detector changes Tracking trigger at lvl 1 (CMS study)

LHC detector upgradesSteinar STAPNES25 Current activities R&D ongoing and organisation  Several groups around the world work on electronics, sensors, powering and simulation studies for SLHC, mostly groups close to completing their construction tasks (a few examples have been shown).  Many groups request guidance and organisation for hardware R&D projects (and establish resources).  RD50 is a very active in the area of sensor R&D, most of it is very relevant for SLHC. Work ongoing:  In ATLAS: Steering Group established, two workshops in Feb and July o Plan to organise R&D with Steering Group and Project Office as part of technical coordination to ensure coherence.  In CMS: Three workshops on SLHC; Feb 2004, July 2004, July o To assist in the R&D project definition, already agreed CMS peer-review scheme. Main lines identified:  Tracker & Trigger  Microelectronics and Power  Optoelectronics & data architectures o Aim to merge at early stage into system(s)  ATLAS and CMS are also discussing collaborative efforts when appropriate. Organisation inside the experiments:  Encourage guided R&D fitting into plans and schedules for upgrades  Make sure there are clear guidelines for what R&D projects should be supported (by the experiments)  Make sure the human resources and experitise existing in the detector communities are kept active in the work to optimise the detectors in the future, for changes, upgrades and adaptations Overall and common view:

LHC detector upgradesSteinar STAPNES26 LHC detector upgrade Conclusions Physics case strong for increased luminosity – our understanding will obviously develop as the initial LHC operation get underway Detectors will need to develop with luminosity (and maybe for other more pragmatic reasons – performance, lifetimes, etc)  New ID (fully or partly) needed for substantial higher luminosity Keep in mind that both experiments foresee to change innermost PIXEL layer(s) anyway after some years, and this is a significant intermediate milestone Technology seems feasible but several R&D efforts needed to prove it and to optimise  Both experiments want to minimize other changes, both to calorimeter and muon electronics, and large infrastructural items  BCO frequency for SLHC need to be agreed  Need early operation experience and background rates at LHC in particular to see if the current muon systems are ok  Need good radiation level and activation studies, and together with the machine, to optimise the forward region close to (and including) the beampipe  Changes needed to DAQ/trigger - some of these can probably be partly anticipated in natural upgrades over the coming years, a tracking trigger at L1 is being considered  Costs significant – rough estimates at 30-50% of current detectors

LHC detector upgradesSteinar STAPNES27 LHC detector upgrade Conclusions ATLAS and CMS already have significant activities related to detector upgrade for SLHC, and are establishing internal organisations to direct, encourage, optimise and collaborate in the developments …. HOWEVER – our main focus is to get started with LHC, probably the by far most important next step for all of us! THE END Many thanks to my ATLAS, CMS and LHC machine colleagues for information, comments and corrections