update on lhc upgrade plans frank zimmermann atlas upgrade week tuesday 10 november 2009

Update on LHC Upgrade Plans

Frank ZimmermannATLAS Upgrade Week

Tuesday 10 November 2009

progress report on Linac4new Phase-I quadrupolesPhase-I schedule Phase-II: progress in various proposed machine schemeschances of having luminosity levellinglikely 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

disclaimerLHC upgrade plans and schedule arepresently under review at • LHC Machine Committee (weekly)• special “brainstorming” meetings• directorate retreat mid-November• Chamonix 2010 workshop (Jan. ‘10)• CERN MAC (1st mtg. 26 October)

previous assumptions & schedules are likely to change significantlymy 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.

PS

PSB

Future SPL

Transfer line

Linac4 Present 50 MeV Linac2

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

Energy [MeV]

Length [m]

RF power [MW]

Focusing

RFQ 0.045 – 3 3 0.6 RF focusing DTL 3 – 50 19 5 112 perm. quads CCDTL 50 – 102 25 7 21 EM quads PIMS 102 – 160 22 6 12 EM quads

Maurizio Vretenar

Linac4 accelerating structures

DTL, 3 – 50 MeV CCDTL, 50 – 100 MeV PIMS, 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 2010.

Linac4 construction site – 5.5.09

Maurizio Vretenar

Linac4 construction site – 27.8.09

Maurizio Vretenar

The 3 MeV Test StandUnder 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

klystronmodulator

sourceRFQchopper line

diagnostics line

Maurizio Vretenar

Linac4 Status – October 2009o 3 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

o Prototypes of accelerating structures tested (CCDTL), under test (DTL), in construction (PIMS). Construction of DTL and CCDTL start in 2009, material procured.

o Started preparation of large contracts (klystrons, modulators, magnets,…).

o Setting 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 PlanMILESTONES:

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 2014.

ID Task Name

1 Linac4 project start

2 Linac systems

3 Source and LEBT construction, test

4 Drawings, material procurement

5 RFQ construction and commissioning

6 Accelerating structures construction

7 Klystron prototypying

8 Klystrons production

9 Transfer l ine construction and instal lation

10 Magnets construction

11 Power converters construction

12 Building and infrastructure

13 Building design and construction

14 Infrastructure installation

15 PS Booster systems

16 PSB injection elements construction

17 Installation and commissioning

18 Test stand operation (3 + 10 MeV)

19 Cavities testing, conditioning

20 Cabling, waveguides installation

21 Accelerator instal lation

22 Klystrons, modulators installation

23 Hardware tests

24 Front-end commissioning

25 Linac accelerator commissioning

26 Transfer l ine commissioning

27 PSB modifications

28 PSB commissioning with Linac4

29 PSB beam ready for PS

01/01

01/04

Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q32008 2009 2010 2011 2012 2013 2014

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 section Separation 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 ~ 180 W @ 1.9 K

→ 120 T/m

→ 120 mm

Phase I

→ 0.25 m→ 500 W

LHC IR Upgrade - Phase IGoals 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 [email protected] 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 optimizationat beam-beam limit:

LQbb Nb*

Qbb Nb

R(*)4 different upgrade strategies:1) * & N/ const., increase Nb with requires controlled blow up at top energy; 2) constant & increase Nb 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

R(*)

*

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

• 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)• 1st proposed in 1988, in operation at KEKB since 2007

→ world record luminosity!

schematic of “LPA” collisions

c

1) large Piwinski angle c z >> 2 x* 2) longitudinally flat profile→ reduced tune shift, higher bunch charge

crab cavities

Name Event DateName Event Date2727

LHC-CC09 workshopLHC Crab Cavity Workshop, jointly organized by CERN, EuCARD-ACCNET, US-LARP, KEK, & Daresbury Lab/Cockcroft InstituteCERN, 16-18 September 2009

~50 participants, LHC Crab Cavity Advisory Board established


CERNCERNstatementstatement

(Steve Myers) (Steve Myers) on LHC crab on LHC crab

cavitiescavitiesissued after issued after

AccNetAccNetLHC-CC09 LHC-CC09 workshopworkshop


CERN statements (excerpts)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


CC designs presented at LHC-CC09CC designs presented at LHC-CC09


further crab cavity progressfurther 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


LPA progressLPA progress

Example: Bunch Flattening of the LHC Beam at 7 TeVExample: Bunch Flattening of the LHC Beam at 7 TeVwith 400MHz and 200MHz RF systemswith 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)


flatness along flatness along the PS batchthe PS batch

Chandra Bhat,Heiko Damerau,et al.

transient beam loading compensation may be required

LPA experiments in PS & SPSLPA experiments in PS & SPS

electron cloud

0.0 4.0x1010 8.0x1010 1.2x1011 1.6x1011 2.0x1011

0

1

2

3

4

5Average heat load - 2nd batch - 25 ns spacing

H

ea

t lo

ad

(W

/m)

Nb

yield = 1.1 yield = 1.2 yield = 1.3 yield = 1.4 yield = 1.5 yield = 1.6 yield = 1.7 cooling capacity high luminosity cooling capacity low luminosity

Humberto Maury Cuna, CINVESTAV, Mexico, FP7 EUROLUMI collaboration!

e- heat load for 25 ns spacing

“ultimate”ES/FCC upgrade

nominal

cooling capacityfor 0.55 m *

SEY up to 1.4 OK with dedicated IR cryoplant

0 1x1011 2x1011 3x1011 4x1011 5x1011 6x1011

0.0

0.5

1.0

1.5

2.0

2.5

Average heat load - 2nd batch - 50ns - LPA schemeH

ea

t lo

ad

(W

/m)

Nb

yield = 1.1 yield = 1.3 yield = 1.5 yield = 1.7 cooling capacity low luminosity cooling capacity high luminosity

(longer flat bunches)

Humberto Maury Cuna, CINVESTAV, Mexico, FP7 EUROLUMI collaboration!

e- heat load for 50 ns spacing

LPA upgrade

need fordedicatedIR cryoplantIRs

SEY up to 1.5 OK

phase-II scenariosin practice

luminosity evolutionluminosity evolution

averageluminosity

event pile upevent pile up

luminosity lifetime

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

L

Ibeamlumi

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 keepluminosity 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

totIP

bbeff

Ln

nN

ˆ 2/1

ˆ

efft

LtL

(no) experience with leveling in Tevatron Run-II

V. Lebedev, CARE-HHH BEAM’07

luminosity with levelingluminosity with leveling

averageluminosity

event pile up with levelingevent 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”(?) evolutionand schedule indication

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

beam energy evolution

3.5 TeV from February to June 2010

5 TeV from summer to October 2010or 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



total integrated luminosity

lifetime limit of IR quadrupoles(LHC PR 633 andRanko Ostojic)estimate from

last week’s LMC



peak luminosity



peak pile up

total intensity / beam



collimationupgrades

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 conclusionsLinac4 on track, connection to PSB may be 1 year delayed (2014/15)reaching 7 TeV requires further consolidation and downtimespossible revision of upgrade schedule & planphase-I IR upgrade might be delayed by 2-3 years to ~2017 parallel effort on LHC crab cavities very rough estimate of 200-300 fb-1 by 2017 luminosity leveling likely to happen when needed

warning: all expectations may prove completely wrong!

generated tracks per crossing, pt > 1 GeV/c cut, i.e. all soft tracks removed!10103535cmcm-2-2ss-1-1

I. Osborne

update on lhc upgrade plans frank zimmermann atlas upgrade week tuesday 10 november 2009

Documents

beam energy beam dump

beamenergy development

linac2 linac4

high energy

cern site

construction drift tube

maurizio vretenarlinac4

cern mac