Update on LHC Upgrade Plans Frank Zimmermann ATLAS Upgrade Week Tuesday 10 November 2009

progress report on Linac4 new Phase-I quadrupoles Phase-I schedule Phase-II: progress in various proposed machine schemes chances of having luminosity levelling likely luminosity, integrated luminosity, and beam-energy development between one year from now and Phase-I list of the major work needed to reach design luminosity and energy, and which works can be done in parallel in a shut-down, and some indication of how this work will be scheduled contents - “requests” for this talk

disclaimer LHC upgrade plans and schedule are presently under review at LHC Machine Committee (weekly) special “brainstorming” meetings directorate retreat mid-November Chamonix 2010 workshop (Jan. ‘10) CERN MAC (1 st mtg. 26 October) previous assumptions & schedules are likely to change significantly my talk may be obsolete in January 2010

Linac-4 progress

Linac4 Linac4 because the 4th linear accelerator to be built at CERN, replacing the present Linac2 as proton injector for the CERN accelerator complex. Civil engineering works have started in one of the last free locations on the CERN site, in a position offering a simple connection to the present machines and the option of a future extension to the high-energy SPL linac. Linac4 = a linear particle accelerator producing a beam of 40mA of H − ions and bringing it to an energy of 160 MeV, in about 100m length. 100 m Maurizio Vretenar

Linac4 motivations main bottleneck for higher beam brightness (beam current/emittance) is “space charge” effects at injection from Linac2 into PSB to overcome this limitation: Linac4 will increase the injection energy, 160 MeV gives factor 2 in beam brightness with respect to Linac2 Linac4 will accelerate H − instead of protons  stripping of electrons at injection in the PSB, denser beams accelerating structures using modern innovative technologies, with improved reliability and low cost open door towards future upgrades of CERN proton complex Maurizio Vretenar

7 Linac4 layout 160 MeV 100 MeV 50 MeV 4 types of NC accelerating structures at 352 MHz, each matched to increasing beam energy; beam dump for setting-up, and switching magnet to the present PSB line Linac4 project includes important modifications to PSB injection region (higher injection energy, H- stripping) Transfer line to PSB Maurizio Vretenar

Linac4 accelerating structures DTL, 3 – 50 MeVCCDTL, 50 – 100 MeVPIMS, 100 – 160 MeV 7-cell cavities in  -mode (12 cavities) Prototype in construction Drift Tube Linac (3 tanks) Prototype built, under testing. Construction starts in 2009 Cell-Coupled Drift Tube Linac (7 modules) Modules of 3 DTL-type cavities (2 drift tubes), connected by coupling cells. Prototypes built and tested, construction starts in 2009 Maurizio Vretenar

Linac4 tunnel (“cut and cover” excavation) seen from high-energy side. Final concrete works starting at low-energy side, excavation proceeding at high energy side. Tunnel level -12 m, length 100 m. Delivery of tunnel and surface equipment building end of Linac4 construction site – Maurizio Vretenar

Linac4 construction site – Maurizio Vretenar

The 3 MeV Test Stand Under construction in the South Hall extension. - H- source (2009) - LEBT (2010) - RFQ (end 2010) - Chopper line (2008) - Diagnostics line (2010) - Infrastructure (1 LEP Klystron, pulsed modulator, etc.). Front end concentrates some of the most challenging linac technologies, and this is where the beam quality is generated. Early understanding and optimization of front-end is fundamental klystron modulator sourceRFQ chopper line diagnostics line Maurizio Vretenar

Linac4 Status – October 2009 o3 MeV Test stand for Linac4 Front-end (Bld. 152): - Infrastructure completed - Prototype modulator and LEP klystron under test - Ion source completed, first beam obtained on 2 July - Chopper line completed - RFQ in construction at CERN Workshop oPrototypes of accelerating structures tested (CCDTL), under test (DTL), in construction (PIMS). Construction of DTL and CCDTL start in 2009, material procured. oStarted preparation of large contracts (klystrons, modulators, magnets,…). oSetting up network of international collaborations to contribute to Linac4 construction (France in-kind, ISTC, India, Poland, …) Blue curve: first 6 mA from ion source the first H- beam at CERN! Maurizio Vretenar

Linac4 Master Plan MILESTONES: Building delivery: December 2010 Infrastructure installation: 2011 Machine and equipment installation: 2012 Linac commissioning: 2013 PSB modifications: shut-down 2013/14. Beam from PSB: April project duration: 6 years 7-month shutdown is needed to connect Linac4 to the PSB; presently 2013/14, but could become 2014/15 - with one additional year for Linac4 commissioning Maurizio Vretenar

phase-I quadrupoles & schedule

ATLAS and CMS interaction regions Dispersion suppressor Matching sectionSeparation dipoles Final focus Triplet position L* = 23 m Triplet gradient 205 T/m Triplet aperture Coil 70 mm Beam screen 60 mm  * = 0.55 m Power in triplet~ K → 120 T/m → 120 mm Phase I → 0.25 m → 500 W

LHC IR Upgrade - Phase I Goals of the upgrade: flexibility & performance; improve spares count; enable focusing of the beams to  *=0.25 m in IP1 and IP5 Scope of the project: 1.Upgrade of ATLAS and CMS interaction regions: Interfaces between LHC and experiments remain unchanged. 2.Cryogenic cooling capacity and other infrastructure in IR1 and IR5 remain unchanged and will be used to full potential. 3.Replace present triplets with wide aperture quadrupoles based on the LHC dipole (Nb-Ti) cables cooled at 1.9 K. 4.Upgrade D1 separation dipole, TAS and other beam-line equipment (also TAN) so as to be compatible with the inner triplets. 5.Modify matching sections (D2-Q4, Q5, Q6) to improve optics flexibility, and introduce other equipment to the extent possible. Ranko Ostojic

IR Phase-I constraints Very tight interfaces between experiments, triplet, TAS, shielding, vacuum and survey equipment, and beam instrumentation; no possibility of reducing L* (23m). Replacement of TAS vacuum chamber. Ultimate cooling capacity is 500 in each triplet. Reduction of  * drives chromatic aberrations all around the LHC. A new optics solution for all arcs and insertions is necessary. All electronics equipment around triplets and DFBX should be located in low-radiation areas. Severe space constraints around IP1 and IP5 Dimensions of new magnets similar to LHC main dipole. Ranko Ostojic

triplet layouts Initial proposal, iterations expected. LHC triplet Phase-I triplet Ranko Ostojic

phase-I merits & concerns +  reduction by almost a factor of 2 + larger aperture in triplet - potential loss in optics flexibility - higher chromaticity & chromatic aberrations - more parasitic long-range beam-beam collisions

phase-I status & schedule conceptual quadrupole design available modifications for matching section under study magnet model work advancing, early 2010 first coils string test planned in SM18 for 2013 for “full” Phase-I upgrade up to 1 year shutdown time line for phase-I upgrade shifting towards ~2017

luminosity optimization & “Phase-II” scenarios

LHC luminosity optimization at beam-beam limit: 4 different upgrade strategies: 1)  * & N/  const., increase N b with  requires controlled  blow up at top energy; 2)  constant & increase N b with 1/R (LPA )  1) and 2) imply larger beam currents! 3) keep N constant and vary  as R (later referred to as small emittance scheme) 4) compensate R at IP and minimize  * (e.g. FCC)  3) and 4) are compatible with ultimate beam parameters - best strategy only known with LHC operational experience - all options require larger triplet aperture & radiation hardness - 2) and 4) may not require any major injector upgrade Oliver Brüning

progress in “phase-II” schemes efforts focus on scenarios FCC & LPA: crab cavities generation & stability of long flat bunches electron cloud simulations

schematic of full crab crossing (“FCC”) cc RF crab cavity deflects head and tail in opposite direction so that collision is effectively “head on” for luminosity and tune shift bunch centroids still cross at an angle (easy separation) 1 st proposed in 1988, in operation at KEKB since 2007 → world record luminosity!

schematic of “LPA” collisions cc 1)large Piwinski angle  c  z >> 2  x * 2)longitudinally flat profile → reduced tune shift, higher bunch charge

crab cavities

Name Event Date Name Event Date27 LHC-CC09 workshop LHC Crab Cavity Workshop, jointly organized by CERN, EuCARD-ACCNET, US-LARP, KEK, & Daresbury Lab/Cockcroft Institute CERN, September 2009 ~50 participants, LHC Crab Cavity Advisory Board established

Name Event Date Name Event Date28 CERN statement (Steve Myers) on LHC crab cavities issued after AccNet LHC-CC09 workshop

Name Event Date Name Event Date29 CERN statements (excerpts) 1.KEKB success … CERN must pursue crab cavities for LHC 2. … Future R&D should focus on compact cavities … suitable for both [local and global] schemes 7.Demonstration experiments should focus on differences between electrons and protons (e.g. effect of crab-cavity noise with beam- beam, impedance, beam loading) and on reliability & machine protection which are critical for LHC 8.A beam test with KEKB crab cavity in another proton machine … useful, meaningful and sufficient … 9. Possible modifications of Interaction Region 4 during the 2013/14 shutdown 11. Crab cavity infrastructure … be included in all … LHC upgrades 12. Crab cavities can increase luminosity w/o accompanying increase in beam intensity, thereby avoiding negative side effects

Name Event Date Name Event Date30 CC designs presented at LHC-CC09

Name Event Date Name Event Date31 further crab cavity progress 30 October 2009: launch of CERN working group on the feasibility of a KEKB crab cavity test in the SPS

large Piwinski angle

Name Event Date Name Event Date33 LPA progress Example: Bunch Flattening of the LHC Beam at 7 TeV with 400MHz and 200MHz RF systems Mountain Range Normal Bunch Flattened Bunch simulation studies and experiments on LPA beam generation & stability by Chandra Bhat (US-LARP/FNAL)

Name Event Date Name Event Date34 flatness along the PS batch Chandra Bhat, Heiko Damerau, et al. transient beam loading compensation may be required LPA experiments in PS & SPS

electron cloud

Humberto Maury Cuna, CINVESTAV, Mexico, FP7 EUROLUMI collaboration! e- heat load for 25 ns spacing “ultimate” ES/FCC upgrade nominal cooling capacity for 0.55 m  * SEY up to 1.4 OK with dedicated IR cryoplant

(longer flat bunches) Humberto Maury Cuna, CINVESTAV, Mexico, FP7 EUROLUMI collaboration! e- heat load for 50 ns spacing LPA upgrade need for dedicated IR cryoplant IRs SEY up to 1.5 OK

phase-II scenarios in practice

luminosity evolution average luminosity

event pile up

luminosity lifetime for a desired luminosity L, the luminosity lifetime depends only on the beam current [without leveling]

luminosity leveling

“luminosity leveling” expected very fast decay of luminosity (few hours) dominated by proton burn off in collisions luminosity leveling (changing  c,  * or  z in store to keep luminosity constant) → reducing maximum event pile up & peak power deposited in IR magnets leveling with crossing angle offers distinct advantages: - increased average luminosity if beam current not limited - operational simplicity natural option for early separation or crab cavities may first be tested in LHC heavy-ion collisions

(no) experience with leveling in Tevatron Run-II V. Lebedev, CARE-HHH BEAM’07

luminosity with leveling average luminosity

event pile up with leveling

experimenters’ choice: no accelerator components inside detector lowest possible event pile up possibility of easy luminosity leveling → Full Crab Crossing upgrade, with Large Piwinski Angle as back up

“likely”(?) evolution and schedule indication my own guesses, based on some indications, huge error bars …

beam energy evolution 3.5 TeV from February to June TeV from summer to October 2010 or in 2011? 6.5 TeV from summer or fall 2011?? 7 TeV from 2012 or 13 onward???

~ forecast from Steve Myers and Roger Bailey shutdown for Linac4 connection IR upgrade + crab cavities luminosity per year

shutdown for Linac4 connection IR upgrade + crab cavities total integrated luminosity lifetime limit of IR quadrupoles (LHC PR 633 and Ranko Ostojic) estimate from last week’s LMC

shutdown for Linac4 connection IR upgrade + crab cavities peak luminosity

shutdown for Linac4 connection IR upgrade + crab cavities peak pile up

total intensity / beam shutdown for Linac4 connection IR upgrade + crab cavities collimation upgrades

major work needed to reach design energy + luminosity commissioning of nQPS system (3 weeks in early 2010) pressure relief valves in all sectors (shutdown 2010/11) splices: monitoring and repair; interventions on about 15% of 13-kA splices – NEW TASK FORCE (all in shutdown 2010/11 optimistically!) magnet training to 7 TeV (6.5 TeV in 2011?, 7 TeV ??) collimation upgrade (as needed)

conclusions my own guesses, based on some indications, huge error bars …

some conclusions Linac4 on track, connection to PSB may be 1 year delayed (2014/15) reaching 7 TeV requires further consolidation and downtimes possible revision of upgrade schedule & plan phase-I IR upgrade might be delayed by 2-3 years to ~2017 parallel effort on LHC crab cavities very rough estimate of fb -1 by 2017 luminosity leveling likely to happen when needed warning: all expectations may prove completely wrong!

generated tracks per crossing, p t > 1 GeV/c cut, i.e. all soft tracks removed! cm -2 s -1 I. Osborne