Collider Options: Linear electron-positron (ILC)

Collider Options: Linear electron-positron

(ILC)

Marc Ross, SLAC – ILC

( with Nick Walker, DESY and Akira Yamamoto, KEK)

10 April, 2013 Marc Ross, SLAC 1

Design: Parameters & LuminosityPower Consumption and Footprint

Upgrade and Staging Strategy

Energy Frontier Lepton Collider Questions:

(Abridged)

1) parameters and key characteristics?

4) power consumption and how does it scale with energy and luminosity? footprint?

5) critical technical challenges? What R&D must be done to address them and what are key demonstrations and milestones? On what timescale? What infrastructure is required?

6) What accelerator R&D is required to realized the physics opportunities in these areas?

8) Are there technology applications beyond energy frontier science that motivate development?


Marc Ross, SLAC 3

International Linear Collider:Outline

• Parameters and Layout– 250 < Ecm < 1000 GeV– Accelerator Subsystems and Footprint

• SCRF Linac Accelerator R & D and Technology– Demonstrations and Key Milestones– Power consumption

• Upgrades and Staging strategy

10 April, 2013

Marc Ross, SLAC 4


• Parameters and Layout– 250 < Ecm < 1000 GeV– Accelerator Subsystems and Footprint



10 April, 2013

N. Walker ILC PAC TDR review

ILC Published Parameters

Collision rate Hz 5Number of bunches 1312 2625Bunch population ×1010 2Bunch separation ns 554 366Pulse current mA 5.8 8.8Beam pulse length ms 730 960RMS bunch length mm 0.3Horizontal emittance mm 10Vertical emittance nm 35Electron polarisation % 80Positron polarisation % 30

Centre-of-mass independent: Luminosity

Upgrade

Advantage of SCRF technology: long pulses

13.12.12 5



Centre-of-mass dependent:

Centre-of-mass energy GeV 200 230 250 350 500Electron RMS energy spread % 0.21 0.19 0.19 0.16 0.12Positron RMS energy spread % 0.19 0.16 0.15 0.10 0.07IP horizontal beta function mm 16 16 12 15 11IP vertical beta function mm 0.48 0.48 0.48 0.48 0.48IP RMS horizontal beam size nm 904 843 700 662 474IP RMS veritcal beam size nm 9.3 8.6 8.3 7.0 5.9Vertical disruption parameter 20.4 20.4 23.5 21.1 24.6Enhancement factor 1.83 1.83 1.91 1.84 1.95Geometric luminosity ×1034 cm-2s-1 0.25 0.29 0.36 0.45 0.75

Luminosity ×1034 cm-2s-1 0.50 0.59 0.75 0.93 1.8% luminosity in top 1% DE/E 92% 90% 84% 79% 63%Average energy loss 1% 1% 1% 2% 4%Pairs / BX ×103 41 50 70 89 139Total pair energy / BX TeV 24 34 51 108 344

13.12.12 6



Centre-of-mass dependent:

Centre-of-mass energy GeV 200 230 250 350 500Electron RMS energy spread % 0.21 0.19 0.19 0.16 0.12Positron RMS energy spread % 0.19 0.16 0.15 0.10 0.07IP horizontal beta function mm 16 16 12 15 11IP vertical beta function mm 0.48 0.48 0.48 0.48 0.48IP RMS horizontal beam size nm 904 843 700 662 474IP RMS veritcal beam size nm 9.3 8.6 8.3 7.0 5.9Vertical disruption parameter 20.4 20.4 23.5 21.1 24.6Enhancement factor 1.83 1.83 1.91 1.84 1.95Geometric luminosity ×1034 cm-2s-1 0.25 0.29 0.36 0.45 0.75

Luminosity ×1034 cm-2s-1 0.50 0.59 0.75 0.93 1.8% luminosity in top 1% DE/E 92% 90% 84% 79% 63%Average energy loss 1% 1% 1% 2% 4%Pairs / BX ×103 41 50 70 89 139Total pair energy / BX TeV 24 34 51 108 344

Focus of design (and cost!) effort

13.12.12 7

ILC in a NutshellDamping Rings

Polarised electron source

Polarised positronsource

Ring to Main Linac (RTML)(inc. bunch compressors)

e- Main Linac

Beam Delivery System (BDS) & physics detectors

e+ Main Linac

Beam dump

not too scale

310 x football pitch

Total site length (500 GeV CM) 30.5 km

SCRF Main Linacs 22.2 km

RTML (bunch compressors) 2.8 km

Positron source 1.1 km

BDS / IR 4.5 km

Damping Rings (circumference) 3.2 km


Ring To Main Linac (RTML)5 GeV

15 GeV

5 GeV

5 GeV 15 GeV

5 GeV

(FoDo lattice)

bunch length: 6 mm 0.9 mm 0.3 mm

beam energy: 5 GeV 4.8 GeV 15 GeV

DE/E: 0.11% 1.42% 1.12%

÷6.7 ÷3

R56 = -372 mm R56 = -55 mm

US R&D Lead: Fermilab


RTML / Bunch Compressor

• Emittance preservation primary challenge– fast ion instability in ~30km long return line– stray time-varying fields (≤2 nT).– spin rotation (solenoids x-y coupling)– RF and long bunch / large DE/E

• wakefields, coupler kicks, cavity tilt effects…

– beam based alignment

• Tight requirements on phase/amplitude stability– timing at IP luminosity loss– 0.24° / 0.48° stability (correlated/uncorrelated)– LLRF challenge

13.12.12 10


Central Region

• 5.6 km region around IR

• Systems:– electron source– positron source– beam delivery system– RTML (return line)– IR (detector hall)– damping rings

• Sized for 1 TeV Ecm

Central Region

common tunnel

13.12.12 11

Central RegionExample: Flat Topography The central region

beam tunnel remains a complex region.

Complete, detailed and integrated lattices are now available

Generic design used for geometry and generating component counts and CFS requirements.

CFS (particularly CE) solutions are site-dependent!

service tunnel


Damping RingsCircumference 3.2 kmEnergy 5 GeVRF frequency 650 MHzBeam current 390 mAStore time 200 (100) msTrans. damping time

24 (13) ms

Extracted emittance x 5.5 mm(normalised) y 20 nm

No. cavities 10 (12)Total voltage 14 (22) MVRF power / coupler 176 (272) kW

No.wiggler magnets 54Total length wiggler 113 mWiggler field 1.5 (2.2) T

Radiated power 1.76 (2.38) MW

Values in () are for 10-Hz mode

Many similarities to modern 3rd-generation light sources

13.12.12 13US Lead: Cornell


Positron Source (central region)

• located at exit of electron Main Linac• 147m SC helical undulator• driven by primary electron beam (150-

250 GeV)• produces ~30 MeV photons• converted in thin target into e+e- pairs

not to scale!

yield = 1.5

13.12.12 14US Lead: ANL


Polarised Electron Source

• Laser-driven photo cathode (GaAs)• DC gun• Integrated into common tunnel with positron

BDS

13.12.12 15US Leads : SLAC and JLAB


BDS and MDI

e- BDSe+ source

electron Beam Delivery System

Geometry ready for TeV upgrade

13.12.12 16US Lead: SLAC


IR region (Final Doublet)• FD arrangement for push pull

– different L*– ILD 4.5m, SiD 3.5m

• Short FD for low Ecm

– Reduced bx*• increased collimation depth

– “universal” FD• avoid the need to exchange FD• conceptual - requires study

• Many integration issues remain– requires engineering studies beyond TDR– No apparent show stoppers

BNL prototype of self shielded quad

13.12.12 17


MDI (Detector Hall)

Mountainous-topography detector hall concept

13.12.12 18


Emittance Preservation

• Damping Ring: gey = 20nm – ~30km RTML return line– Turn around and spin rotation– Bunch compressor (two-stages)– Acceleration (10km main linac)– Positron production (e- only)– Beam delivery system (non-linear optics)– Final Doublet and collision!

• Budget 15 nm gey = 35 nm at IP

13.12.12 19

M. Ross, SLAC 21

Tunnel Lengths and volumes

10 April, 2013

As

ia

Marc Ross, SLAC 22


• Parameters– 250 < Ecm < 1000 GeV– Footprint Accelerator Subsystems



10 April, 2013

Site-Dependent Designs• Top-level parameters• Accelerator layout

– lattice– geometry– parameters– etc.

• Conventional Facilities / Siting (CFS) requirements– Central region (source, BDS, DR)– RTML (bunch compressors)

• Civil engineering solutions– topography– geology

• Main linac layout• RF power distribution

– Klystron Cluster ‘KCS’– Dist. Multi-Beam Klystron ‘MBK’

cost effective tunnelling methods

23

SCRF Linac Technology

1.3 GHz Nb 9-cellCavities 16,024

Cryomodules 1,855

SC quadrupole pkg 673

10 MW MB Klystrons & modulators

436 *

Approximately 20 years of R&D worldwide Mature technology

* site dependent

24

ILC Cavity Assembly (Helium tank, mag. shield, tuner and coupler)

Graphics by Rey. Hori

Linac building block: the Cryomodule:

25 February, 2013 Marc Ross, SLAC 27

Graphics by Rey. Hori

12 GeV cavities: overall performanceCEBAF 12 GeV upgrade

72/85 @ admin limit (85%)

Cavities made by RI (Germany); Followed ILC Process

Reported 11.2012 by F. Pilat

Vertical Test; 1500 MHz 7 cell; 10% gradient correction


RF Power Source

Marx modulator 10MW MB Klystron

Adjustable local power distribution system

13.12.12 29


Main Linac Parameters (500 GeV)Average accelerating gradient 31.5 (±20%) MV/m

Cavity Q0 1010

(Cavity qualification gradient 35 (±20%) MV/m)

Beam current 5.8 mA

Number of bunches per pulse 1312

Charge per bunch 3.2 nC

Bunch spacing 554 ns

Beam pulse length 730 ms

RF pulse length (incl. fill time) 1.65 ms

Efficiency (RFbeam) 0.44

Pulse repetition rate 5 Hz

Peak beam power per cavity 189* kW

* at 31.5 MV/m

13.12.12 30

M. Ross, SLAC 31

MR Linac tunnel cross-section:

10 April, 2013

• Personnel can occupy klystron area during operation– Radiation

analysis later in presentation

• Cross-over paths for egress (500 m)

• 11 m wide x 5.5 m high– dimensions in

mm

M. Ross, SLAC

• 1:50 scale model

• (KEK 2 April)

10 April, 2013 32

Tunnel Model:


RF Power sources underground:

13.12.12

accelerator cryomodules

DistributedKlystronScheme

34

35

Candidate site (1 of 2) in northeastern Japan Tohoku ‘Mountain Region’

(Photo taken100 km north of Sendai.)

The ILC alignment would be 50 to 400 meters below these hills.

10 April, 2013 M. Ross, SLAC

36

Operations – Peak Power

DKS

74% RF power to beam

(189 + 67 KW generated per cavity)

10 April, 2013 M. Ross, SLAC

189 KW peak delivered to average cavity• (Distributed Klystron)

KW peak% of total

Single Klystron output 10,000.0

N cavities 39.0Per cavity

256.4 100%Klystron margin 251.9 98%LPDS loss 226.0 88%LLRF Overhead 211.2 82%Extra power for ±20% 189.2 74%

Heat Load and Power Flow

37

Waste heat: • for each klystron station

(surface) and– 73 kW

• for each ML 3 cryomodule unit (tunnel)– 50 kW– 1.3 kW to tunnel air

• 740 kW to air (ML total)• air / water fraction

– 33 W/meter to air– Does not include

‘cooling’ due to cryomodules (~ 150 W 10% reduction)

(KCS)

COMPONENTS IN THE SURFACE (listed as per RF)

To LCW to CHW

Average

Heat Load

(KW)

Heat Load to LCW Water (KW)

Racks Heat Load

(KW)

Heat Load to

Air

(KW) RF Components x (413 )

RF Charging Supply 2.39 1.7 0.7

Switching power supply 5.5 3.3 2.2Filament Transformer 0.79 0.6 0.2Marx Modulator 4.96 3.0 2.0Klystrn Scket Tank / Gun 0.99 0.8 0.2Focusing Coil (Solenoid ) 1.68 1.6 0.1Klystron Collector 38.43 37.1 1.3Klystron Body & Windows 3.37 3.4CTOs & combining Loads/circulators 11.71 9.4 2.3

Relay Racks (Instrument Racks) 3.0 0 3 0.0

Subtotal surface RF& NonRF unit Only (for 1 RF) 60.74 3.0 9.1

COMPONENTS IN THE TUNNEL (listed as per RF)RF Components (x 567)

RF Pipe in Shaft (shaft & bends) 1.89 1.7 0.2Relay Racks (Instrument Racks) 5 0.0Main tunnel Wvgde & local wvgd 12.23 11.6 0.6Distribution Edn Loads & Cavity Reflection loads

31.80 31.30 0.5

Subtotal Tunnel RF& NonRF unit Only (for 1 RF) 49.62 1.3

To AIR

Su

rfac

eTu

nn

elper ML unit

per ML unit

10 April, 2013

M. Ross, SLAC 38

AC Power Consumption

10 April, 2013

Asi

a to

tal

(MW

)(m

ou

nta

in)

Lin

ac

to

tals

(M

W)

Collider ‘Wall Plug’ AC Power use:

10 April, 2013 M. Ross, SLAC 39

ILC and 80 km ring: ILC -H ILC-nom

E_cm (GeV) 250 500

SRF Power to Beam (MW) 5.2 10.5

Eff. RF Length (m) 7,837 15,674

RF klystron peak efficiency (%) 65 65

klystron operating margin, HVPS, Klystron Aux and klystron water cooling (% inefficiency)

30 + 20Additional inefficiency due cavity fill-time

Overall system RF efficiency (%) 10 14

Cryo (MW) 16 32

Normal Conducting (exc. Injector complex) (MW)

6 10

Injector complex 32 32

Conventional (Air, lighting, ..) 6 6*

Total (exc. detector) 112 153

* 5% for operating margin, 2% for auxiliaries, 3% for HVPS and 10% for water cooling* 6 MW for 30 km beam tunnel complex

Parametric ‘value’ costing (KILCU):

• Civil Construction: 35 / m• Utilities: 5000 / MW• Superconducting RF 180 / m (inclusive)• ‘Conventional Acc.’ 35 / m


ILC quantity MILCU

Civil Construction km 34 1200Power and cooling MW 162 800SRF (incl. packing) km 22 4000‘Conventional’ km 12 800Installation km 34 100Total 7800

Institutional Labor is part of the project cost and must also be analyzed.

M. Ross, SLAC 41


• Parameters– 250 < Ecm < 1000 GeV– Footprint Accelerator Subsystems



10 April, 2013

Staging and Upgrades:

Beam Energy and Beam Power:• Staging and

Upgrade Strategies


1500 GeV E_cm2450 bunches






Beam intensity

E_

cm

Design Baseline


Low Ecm Running (<300 GeV)

• Positron production (yield) drops with <150 GeV• Low Ecm running (≤250 GeV) 10Hz mode

• Alternate pulses for e+ production:– 150 GeV e- pulse to generate positrons– Ecm/2 e- pulse for luminosity

• Ramifications:– 100ms store time in DR shorter damping times– Need to dump 150 GeV production pulse after undulator (new

beamline, pulsed-magnet system)– Pulsed trajectory-correction system before undulator for 150

GeV production beam.

• Electron Main Linac requires no modification– Installed AC power sufficient for ~½ energy operation at 10Hz.

13.12.12 43


Luminosity Upgrade

• Concept: increase nb from 1312 → 2625– Reduce linac bunch spacing 554 ns → 336 ns– Increase pulse current 5.8 → 8.8 mA– Increase number of klystrons by ~50%

• Doubles beam power ×2 L (3.6×1034cm-2s-1)

• Damping ring:– Electron ring doubles current (389mA 778mA)– Positron ring: possible 2nd (stacked) ring (e-cloud limit)

• AC power: 161 MW 204 MW (est.)– AC power increased by ×1.5– shorter fill time and longer beam pulse results in higher RF-beam

efficiency (44% 61%)

13.12.12 44


Luminosity UpgradeAdding klystrons (and modulators)

MountainTopography (DKS)

Damping Ring:

13.12.12 45


TeV Upgrade

2.2 km

1.3

km10.8 km

1.1

km

BDSMain Linac

e+ s

rc

bun

ch c

omp.

<26 km ?(site length <52 km ?)

Main Linac<Gcavity> = 31.5 MV/m Geff ≈ 22.7 MV/m(fill fact. = 0.72)

IP

central region

<10.8 km ?

Snowmass 2005 baseline recommendation for TeV upgrade: Gcavity = 36 MV/m ⇒ 9.6 km (VT ≥ 40 MV/m)

Based on use of low-loss or re-entrant cavity shapes

Assume Higher

Gradient

13.12.12 46


TeV upgrade: Construction Scenario

BDSMain Linac

e+ s

rc

IPBC

BDSMain Linac

e+ s

rc

IPBC

BDSMain Linac

e+ s

rc

IPBC

BDSMain Linac

e+ s

rc

IPBC

start civil construction500GeV operations

500GeV operations

Installation/upgrade shutdown

civil construction + installation

final installation/connectionremoval/relocation of BCRemoval of turnaround etc.

Installation of addition magnets etc.

Commissioning / operation at 1TeV

13.12.12 47

TeV Parameters (2 sets)

low and high beamstrahlung

horizontal focusing main difference

shorter bunch length(within BC range)

PAC constrained ≤300 MW

ILC at low/high Ecm• Low Ecm operation of upgraded ILC:

– L250 ~ 3e34; Wall plug 200 MW

– Higgs Factory Option

• High Ecm ~ 1.5 TeV – L1500 ~ 6e34; Wall plug 340 MW


0 200 400 600 800 1000 1200 1400 16000.1

1

10

Luminosity vs Energy

ILC upgradeILC Nom

E_cm (GeV)

Lum

i (e

34)

Collider Options: Linear electron-positron (ILC)

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Transcript of Collider Options: Linear electron-positron (ILC)