explore feasibility and limiting factors of large ... · large-acceptance recirculating...

Explore feasibility and limiting factors of large-acceptance Recirculating Linearlarge acceptance Recirculating Linear

Accelerators (RLAs) based on Superconducting RF

Alex BogaczgCASA

Director’s Review of Accelerator R&DMarch 20, 2009

Outline

• Design of multi-GeV muon accelerator complex for future Neutrino Factory – International Design StudyNeutrino Factory International Design Study

• TeV-scale muon acceleration for future Muon Collider

• Extreme muon cooling schemes for Low Emittance Muon C llidCollider

• Collaborations & PartnershipsCollaborations & Partnerships

• Summary

y

Motivation − Scientific Case

• Muon Colliders and Neutrino Factories are attractive options for future facilities aimed at achieving the highest lepton-antilepton collision energies (e.g. to mass-produce Higgs bosons in s-channel) and precision measurements of parameters of the neutrino mixing matrix with intense (1014

μ/sec), small divergence neutrino beams with well-understood systematics. μ ), g y

• Their performance and feasibility depend strongly on how well a muon beam can be cooled and accelerated to multi-GeV and TeV energies. g

• Recent progress in muon cooling and acceleration (International Design Study and prototype tests) encourages the hope that such facilities can be built during the next decade…

• Funding for these studies provided by: HEP and SBIR/STTR grants

Opportunities and Challenges

• Future Muon facilities based on muon storage rings will require innovative SRF linacs to:acs to

• Longitudinally compress and ‘shape’ them into a beam

• μs are produced in a tertiary process into a large emittance (p + A → π → μ)

• Rapidly accelerate them to multi-GeV (NF) and TeV (MC) energies

• it has a short life time (2.2 μsec) in its own rest frame

• high gradient, fixed field accelerator

• Why Recirculating Linear Accelerators based on SRF?

• RLAs are possible because muons do not generate significant synchrotron radiation

• high energies and in strong magnetic fields (mμ = 105 MeV/c2)

• Huge initial phase-space requires large acceptances (both trans/longit)

• Large intensities call for RF operating at stored energy

Large intensities call for RF operating at stored energy

Design of multi-GeV muon accelerator complex for future Neutrino Factory –complex for future Neutrino Factory

International Design Study

Multi-GeV muon RLAs for Neutrino Factory• Conceptual design of an RLA based Muon Accelerator Complex

(as part of NF International Design Study)

trans. norm. acceptance (30 mm-rad)long. acceptance (150 mm-rad)

12.6-25 GeV

• 200 MHz SRF Linac (0.3 to 0.9 GeV)

R id l ti f h t li d hi h di t SRF• Rapid acceleration of short lived muons, high gradient SRF

• ‘Full bucket’ acceleration and longitudinal bunch compression

• Two-step, vertically stacked ‘dogbone’ RLAs (0.9 to 12.6 GeV)• phase slippage, RF cavities synchronized for a speed of light particle

phase slippage, RF cavities synchronized for a speed of light particle • simultaneous acceleration of μ+ and μ- charge species

‘Dogbone’ vs ‘Racetrack’ RLA (both μ+ and μ-)

μ−

μ+μ+ μ− μ+ μ−

μ−

μ+

μ−

μ+

μ+ μ−

ΔE

• better orbit separation at linac’s end ~ energy difference between consecutive passes (2ΔE)

• allows both charges to traverse the linac in the same direction (more uniform focusing profile

ΔE/2

μ+μ+ μ−

μ−

ΔE/2

Linear Pre-accelerator – 240 to 900 MeVTue Feb 12 12:50:16 2008 OptiM - MAIN: - M:\casa\acc_phys\bogacz\IDS\PreLinac\Linac_sol.opt

30

30

] ]

Siz

e_

X[c

m

Siz

e_

Y[c

m

Transverse acceptance (normalized): (2.5)2εΝ = 30 mm rad

Longitudinal acceptance: (2 5)2 σ σ /m c = 150 mm

1460

0 0

Ax_bet Ay_bet Ax_disp Ay_disp

Longitudinal acceptance: (2.5) σΔpσz/mμc = 150 mm

6 short cryos 8 medium cryos 11 long cryos17 MV/m

1.1 Tesla solenoid 1.4 Tesla solenoid 2.4 Tesla solenoid

SRF linac with individually phased RF cavities; far off-crest at the beginning of the linac and gradually brought on-crest by the linac end Induced synchrotron motion is allowing

and gradually brought on-crest by the linac end. Induced synchrotron motion is allowing for longitudinal bunch compression in both length and momentum spread

Pre-accelerator – Longitudinal compressionTue Feb 12 12:50:16 2008 OptiM - MAIN: - M:\casa\acc_phys\bogacz\IDS\PreLinac\Linac_sol.opt

30

30

Siz

e_

X[c

m]

Siz

e_

Y[c

m]

Transverse acceptance (normalized): (2.5)2εΝ = 30 mm rad

1460

0 0

Ax_bet Ay_bet Ax_disp Ay_disp

Longitudinal acceptance: (2.5)2 σΔpσz/mμc = 150 mm

160

16

0,

0d

P/P

* 1

000,

60

dP

/P *

10

00

,

26-26 S [cm] View at the lattice end

-160

25-25 S [cm] View at the lattice beginning

-16

Longitudinal phase-space (s, Δp/p) axis range: s = ±25 cm, Δp/p = ±0.2

Multi-pass linac Optics‘h lf ’ 900 1200 M V‘half pass’ , 900-1200 MeV

initial phase adv/cell 90 deg. scaling quads with energy Fri Jan 23 14:33:20 2009 OptiM - MAIN: - N:\bogacz\IDS\Linacs_bisect\Linac05.opt

15 5

m] quad gradient

BE

TA

_X

&Y

[m

DIS

P_

X&

Y[m

]

1-pass, 1200-1800 MeVmirror symmetric quads in the linac

39.91030

0 0

BETA_X BETA_Y DISP_X DISP_Y

Fri Jan 23 14:56:30 2009 OptiM - MAIN: - N:\bogacz\IDS\Linacs_bisect\Linac1.opt

15 5

X&

Y[m

]

X&

Y[m

]

quad gradient

78.91030

0 0

BE

TA

_X

DIS

P_X


Multi-pass linac Optics4-pass, 3000-3600 MeV phase adv. still larger then 180 deg. in both planes


35 5

[m]

m]

BE

TA

_X

&Y

[

DIS

P_

X&

Y[m

5-pass, 3600-4200 MeV

78.91030

0 0



35 5

&Y

[m]

&Y

[m]

78.91030

0 0

BE

TA

_X

DIS

P_X

&

BETA X BETA Y DISP X DISP Y

78.91030 BETA_X BETA_Y DISP_X DISP_Y

Tue Jun 10 21:14:41 2008 OptiM - MAIN: - D:\IDS\Arcs\Arc1.o

Mirror-symmetric ‘Droplet’ Arc – Opticsp

15 3

[m]

m]

(βout = βin and αout = -αin , matched to the linacs) E =1.2 GeV

BE

TA

_X

&Y

DIS

P_

X&

Y[m

1300

0 -3


10 cells in2 cells out 2 cells out

footprint

3000

4000

5000

transition transition

300

300

-3000

-2000

-1000

0

1000

2000

0 2000 4000 6000 8000 10000x [cm]

0d

P/P

* 1

000,

0dP

/P *

100

0,

-5000

-4000

z [cm]

40-40 S [cm] View at the lattice end

-300

40-40 S [cm] View at the lattice beg

-300

TeV-scale muon acceleration for future Muon Collider

Low Emittance Muon Collider Scenario

‘Pulsed’ linac Dogbone RLA

• Design of a muon RLA based on ILC linac (solicited by Muon Collider Task Force at Fermilab)

3 GeV

33 GeV4 GeV/pass

33 GeV

• Multi-pass linac optics with pulsed quads – newly awarded SBIR with Muons Inc

• Quad pulse would assume 500 Hz cycle ramp with the top pole field of 1 Tesla.

• Mitigation of focusing deficiency - larger number of passes• Mitigation of focusing deficiency - larger number of passes

‘Pulsed’ vs ‘Fixed’ Dogbone RLA Fri Nov 16 16:25:13 2007 OptiM - MAIN: - M:\acc_phys\bogacz\Dogbone_pulsed\pulsed\Linac8.opt

Pulsed

320 5

&Y

[m]

Y[m

]

BE

TA_X

&

DIS

PX

&Y

8-pass, 28-32 GeV5000

0 0


F i N 16 16 09 52 2007 O tiM MAIN M \ h \b \D b l d\fl t\Li 8Fixed

Fri Nov 16 16:09:52 2007 OptiM - MAIN: - M:\acc_phys\bogacz\Dogbone_pulsed\flat\Linac8.o

320 5

&Y

[m]

&Y

[m]

0 0

BE

TA

_X&

DIS

P_X

&

phase adv. diminishes down to 1800

Muon Collider Design Workshop, BNL, Dec. 3-7, 2007

5000

0 0


‘Pulsed’ vs ‘Fixed’ Dogbone RLA Fri Nov 16 16:28:26 2007 OptiM - MAIN: - M:\acc phys\bogacz\Dogbone pulsed\pulsed\Linac12.o

PulsedFri Nov 16 16:28:26 2007 OptiM MAIN: M:\acc_phys\bogacz\Dogbone_pulsed\pulsed\Linac12.o

320 5

Y[m

]

Y[m

]

BE

TA_X

&Y

DIS

PX

&Y

phase adv. diminishes down to 1800

12-pass, 47-51 GeV5000

0 0


Fixed

no phase adv across the linacno phase adv. across the linac-beam envelopes not confined

Large momentum acceptance multi-pass Arc • Non Scaling FFAG Optics

• Compact triplet cells based on opposed

0yB B Gx= +

xB Gy= −

bend combined function magnets

,

For different energies self-similar beta functions in a periodic cell

MADX- Polymorphic Tracking Code. Energy acceptance: -30% to 90%

NS-FFAG multi-pass ‘Droplet’ Arc Wed Nov 19 10:13:45 2008 OptiM - MAIN: - D:\SBIR\FMC\Optics\multi cell oW d N 19 10 11 56 2008 O tiM MAIN D \SBIR\FMC\O ti \ lti ll Wed Nov 19 10:13:45 2008 OptiM - MAIN: - D:\SBIR\FMC\Optics\multi cell.o

7

0.1

X&

Y[m

]

&Y

[m]

Wed Nov 19 10:11:56 2008 OptiM - MAIN: - D:\SBIR\FMC\Optics\multi cell.o

7

0.1

&Y

[m]

&Y

[m]

.1

BE

TA

_X

DIS

P_X

&

1

BE

TA

_X

&

DIS

P_

X&

,

177.7154

0 -0

BETA_X BETA_Y DISP_X DISP_Y4521.27

0 -0.


3000 inward600 outward 600 outward

3000

0

1000

2000

cm]

• MADX-PT − Polymorphic Tracking Code is used to study multi-pass beam dynamics for different pass beams: path length difference, optics mismatch between linac and arcs orbit offset

- 2000

- 1000

00 1000 2000 3000 4000 5000 6000 7000 8000

x[ mismatch between linac and arcs, orbit offset and tune change is being studied.

- 3000z[ cm]

Extreme muon cooling schemes for Low Emittance Muon Collider

Muon Ionization Cooling

Large emittance

Small emittance

ppΔ

Absorber Accelerator Momentum loss is opposite to motion, p, p x, p y, Δ E decrease

Momentum gain is purely longitudinal

emittance

inp

cool out RFp p p= +Δ

abspΔ

Absorber Plate

Longitudinal Emittance Exchange

zRFpΔ

inp

Transverse cooling

Helical Cooling ChannelA li fill d ith hi h h d d i b dd d i t ti

Combined function magnet (invisible in this picture)

A linac filled with high pressure hydrogen gas and imbedded in strong magnetic fields has been proposed to rapidly cool muon beams

Blue: Beam envelopeRed: Reference orbit

g ( )Solenoid + Helical dipole + Helical Quadrupole

Blue: Beam envelope

Dispersive component makes longer path length for higher momentum particle and shorter path length for

2

z

pap

φπκλ

= =

lower momentum particle.

zp

z

z

f b p

f b pϕ

ϕ

↑

↓

∝ ⋅

∝ − ⋅Repulsive force

Attractive force

( )central z zef b p b pm ϕ ϕ= ⋅ − ⋅

zf pϕ↓

Both terms have opposite signs.

Parametric Resonance CoolingTransport channel (between consecutive absorbers) designed to replenish large angular component, x’, sector of the phase-space, ‘mined’ by ionization cooling process.

Normal elliptical motion of a particle’s transverse coordinate in phase

′xx =const

Normal elliptical motion of a particle s transverse coordinate in phase space becomes hyperbolic (half-integer resonance) – resulting beam emittance has a wide spread in x’ and very narrow spread in x. Wed Jun 21 11:47:31 2006 OptiM - MAIN: - D:\Cooling Ring\Snake Channel\snake_100_1.opt

5 3

BE

TA

_X

&Y

[m]

DIS

P_X

&Y

[m]

100

0 -3


beam extension beam extensiondisp. anti-suppr. disp supprn periodic PIC/REMEX cells (n=2)beam extensionRF cavityskew quad

d sp a t supp disp. suppr.

snake - footprint

100

150

200

x [ c m]

0

50

100

0 50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850 900 950 1000

z [ c m]

Epicyclic Helical Solenoid

zikzikT eBeBB 21 |||| 21 +=

3030

• Superimposed transverse magnetic fields with two spatial periods

2020

• Variable dispersion function

1.5

1010

0.5

1

XY-plane

-1.5 -1 -0.5 0.5 1 1.5

-1

-0.5 k1=-2k2B1=2B2 -1

0

-101

-1

-1.5

1 2EXAMPLE

1 0 11 0

Collaborations & PartnershipsCollaborations & Partnerships

Neutrino Factory Muon Collider Collaboration

US I t ti l

National LabsArgonne

UniversitiesColumbia

National LabsBudker

UniversitiesKarlsruhe

US International

BNLFermilab

LBNLOak Ridge

CornellIIT

IndianaMichigan State

DESYINFN

JINR, DubnaKEK

Imperial CollegeLancaster

OsakaOxford

Jefferson Lab MississippiNorthern Illinois

PrincetonUC-Berkeley

RALTRIUMF

PohangTel Aviv

Corporate PartnersUC-DavisUC-Los Angeles

UC-RiversideUniversity of Chicago

Corporate PartnersMuons Inc*

Tech-X Corporation

NFMCC Collaboration Meeting, LBNL, January 27, 2009

International Design Study – Neutrino Factory

SBIR/STTR Grants

Summary

• Muon Colliders & Neutrino Factories will require innovative SRF linacs to: cool/compress and ‘shape’ them into a beam and finally to rapidly accelerate them to multi – GeV (NF) & TeV (MC) i(MC) energies

• Large acceptance Recirculating Linacs − rapid acceleration and effective longitudinal bunch compression

• ‘Dogbone’ (Single Linac) RLA has advantages over the ‘Racetrack’

• better orbit separation for higher passes

• offers symmetric solution for simultaneous acceleration of μ+ and μ-offers symmetric solution for simultaneous acceleration of μ and μ

• Pulsed linac multi-pass Optics….even larger number of passes is possible if the quadrupole focusing can be increased as the beam energy increases

E t C li A li fill d ith hi h h d d i b dd d i t• Extreme Cooling − A linac filled with high pressure hydrogen gas and imbedded in strong magnetic fields has been proposed to rapidly cool muon beams

• Helical Cooling channel

P i R E i li h l

• Parametric Resonance – Epicyclic channels

explore feasibility and limiting factors of large ... · large-acceptance recirculating...

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