Accelerator Research at SLACTor Raubenheimer

Stanford Graduate Student OrientationSeptember 20, 2013

What are accelerators?

Wikipedia: A particle accelerator is a device that uses

electromagnetic fields to propel charged particles to high speeds and

to contain them in well-defined beams

• CRT’s x-ray tubes SRS Large Hadron Collider• Velocity = 0.999999999986 x speed of light at LEP2

~26,000 accelerators worldwide

• ~44% are for radiotherapy, • ~41% for ion implantation, • ~9% for industrial processing and research, • ~4% for biomedical and other low-energy research,• ~1% with energies > 1 GeV for discovery science and research

2Stanford Graduate Student Orientation, 9/20/2013

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Accelerators at SLAC

Stanford Graduate Student Orientation, 9/20/2013

Particle Accelerators at SLAC

XTA

FACET

ASTA

Field of Accelerator Physics

Broad field ranging from engineering

some of the largest scientific instruments

to plasma physics to materials science to

nonlinear dynamics

• Advances come from both

conceptual research and directed

R&D aimed at applications

Field offers opportunity for ‘small-scale’

experiments at large science facilities

• Small groups:- Individuals can engage in

theory, simulation,

and experimental results

LHC

Tevatron

LEP-II

SLCHERA

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Advanced Accelerator Research @ SLAC

High energy particle accelerators are the ultimate microscopes• Reveal fundamental particles and forces in the universe at the energy frontier• Enable x-ray lasers to look at the smallest elements of life

Goal is to shrink the size and cost by factors of 10-1000

Combine SLAC accelerators with lasers, plasmas, high-power

microwaves, and lithography to develop new generation of particle

accelerators and sources

New designs and materials push metal accelerator structures to the limit

Telecom and Semiconductor tools used to make an ‘accelerator on a chip’

Extremely high fields in 1,000°C lithium plasmas have doubled the energy of the 3-km SLAC

linac in just 1 meterStanford Graduate Student Orientation, 9/20/2013

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The E163 Test Facility and the Next Linear Collider Test Accelerator provide unmatched capabilities for testing laser accelerators. The small size of the group (<10) means that

students can be involved in virtually all aspects of the experiment.

Contact: Dr. Joel England, 926-3706 6

Woodpile Structure

Plasma Wakefield Acceleration

Acceleration gradients of ~50

GV/m (3000 x SLAC)

• Doubled energy of 45 GeV

beam in 1 meter plasma

FACET brand-new 20 GeV

test facility for PWFA

Contact: Dr. Mark Hogan, 926-2951Page 7

Stanford Graduate Student Orientation, 9/20/2013

Accelerator Beam Physics and Computing

Broad set of topics ranging from concepts for future high-energy

physics and photon science facilities, to massively parallel

simulations, to beam theory

• Developed many of the innovative concepts of the field including:- Linear collider designs- Linac coherent light source (x-ray FEL)- PEP-X and other future light sources - Massively parallel electromagnetic calculations

Faculty: Alex Chao (926-2985), Ron Ruth (926-3390)

Department heads: Yunhai Cai

and Cho Ng 8

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Compact accelerators

Developing new compact accelerator

for Inverse Compton Scattering,

FEL’s and Ultrafast e- Diffraction

GunLinac YAG, Laser Injection chamber

Cecile Limborg926-8685

Chris Adolphsen926-3560

Undulator Mechanical Structure

Electric Field Distribution

Accelerator Technology Research

High Gradient Research:

• Host for the US Collaboration on High Gradient Research for Future Colliders• RF Superconducting Material Characterization, Geometrical Effects, Frequency scaling,.• High Frequency RF Source Developments.• Novel Accelerator structures

Novel FEL Technologies and Light Sources: RF undulators and bunch compression techniques

for ultra-short pulses.

Advanced Accelerator Concepts: Practical design and implementation

of Terahertz and far infrared accelerators and components

For more info contact: Prof. Sami Tantawi650-926-4454 10

SPEAR3 accelerator research

Short pulses/THz beamline

• LDRD funding to design THz beamline• Primary rotation research focus• Beamline purpose:

- Characterize bunch shape- Measure shielded CSR impedance- THz for photon experiments

Accelerator optics/Nonlinear dynamics

PEP-X (future light source)

Gun development

Diagnostics development

James Safranek, 926-5438

-5 -4 -3 -2 -1 0 1 2 3 4 5-5

-4

-3

-2

-1

0

1

2

3

4

5

x (mm)

Flux: R0= 2 m; 1.2 T, 3.0 GeV, 1.000 eV; I 100mA

y (m

m)

Mea

sure

d

SP

EA

R

bu

nch

Cal

cula

ted

TH

z

Nonlinear dynamics:simulated & measured

Stanford Graduate Student Orientation, 9/20/2013 11

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Large Hadron Collider: Accelerator Research

Stanford Graduate Student Orientation, 9/20/2013

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Advanced Instrumentation and Feedback

• Signal processing systems for beam instrumentation and feedback

control systems. Develop DSP with 4-8 GHz processing bandwidth

for SPS and LHC, participate in machine measurements.

• System modeling and simulation of

unstable systems under feedback

control stabilize jitter in LCLS

• Machine physics studies and system

dynamics characterization of the

LHC RF↔beam interaction

The group comprises SLAC staff, Toohig Fellow and Stanford Ph.D. students.

Two APS Dissertation Prizes in Beam Physics have

been awarded to past students.

Stanford Graduate Student Orientation, 9/20/2013

Contact: John Fox, 926-2789

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LHC Projects

A number of potential thesis projects on LHC

• Crystal collimation with Uli Weinands• HiLum LHC design Yunhai Cai• LLRF, feedback and • Electron cloud instability and control with John Fox

Faculty members:

• John Fox, 926-2789

Senior Staff:

• Tom Markiewicz, 926-2668• Uli Wienands, 926-3817• Yunhai Cai, 926-2935

Stanford Graduate Student Orientation, 9/20/2013

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Linac Coherent Light Source (LCLS)

• World’s first x-ray laser – a Free Electron Laser• Commissioned in 2009 and constantly advancing new concepts

Stanford Graduate Student Orientation, 9/20/2013

April 10, 2009

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LCLS Undulator Hall

Stanford Graduate Student Orientation, 9/20/2013

Slide 17

Stanford Graduate Student Orientation, 9/20/2013

Linac Coherent Light Source IIInjector @1-km point

Sectors 10-20 ofLinac (1 km)(with modifications)

X-ray Transport Optics/Diagnostics

New Underground Experiment Hall

Bypass LCLS LinacIn PEP Line(extended)

New Beam TransportHall

SXR, HXR Undulators

2010: April- Critical Decision 0 approved2011: October- Critical Decision 1 approved2012: March- Critical Decision 3a approved2012: August- Critical Decision 22013: June- Critical Decision 3b2018: Sept. First FEL Light2019: Sept. Critical Decision 4

New Superconducting rf linac at beginning of SLAC Tunnel. New rf test facilities for SCRF cavities and cryomodules. R&D towards super high Q cavities. High frequency rf controls and feedback systems. Strong emphasis on longitudinal phase space control seeding and phase space manipulation.

SASE spectrum Seeded spectrum

Seeding + taper

FEL R&D opportunities @ SLAC

• LCLS is the world’s brightest x-ray source. - You have the opportunity to

make it even

brighter!

• Seeding improves spectral brightness

• Tapered undulator increases

FEL power to Terawatt level

Many challenging theoretical,

computational, and experimental topics

to pursue in the coming years (see next slide) 18

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FEL R&D at the NLC Test Accelerator

Compact accelerator test facility dedicated to accelerator R&D. Three

parallel programs: X-band Test Accelerator; Direct Laser Acceleration;

Echo-75 R&D.

Echo program is aimed at manipulating

longitudinal beam structure at the nm-scale.

Combination of laser and beam physics R&D

use lasers to make beams do crazy things!

>10 peer reviewed papers

over last year with new

ideas coming all the time.

Tor Raubenheimer,

650-714-2156

Stanford Graduate Student Orientation, 9/20/2013

2011-12 2015-162013-14 2017-18 2019-20

LCLS-II injector LCLS-II completion

HXRSS

Injector R&D

S0 ITF: advanced beam generation, high-energy compression and laser seeding

Temporal diagnostics & timing

Attosecond x-ray generation

X-ray seeding & brightness

E-beam brightness & manipulation

Technologydevelopment

Ultrafast techniques

ECHO-7

Soft X-Ray Self-Seeding

ECHO-75, laser phase error error

THz & Polarization

THz

Polarization control

Multi bunches, detectors, novel undulators, high-rep. rate

ASTA (Cathode, Gun)

X-ray sharing

TWFEL

HHG efficiency and control

Completed Ongoing Under development

SLAC FEL R&D roadmap

HXRSS

Stanford Graduate Student Orientation, 9/20/2013 20

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SLAC Facilities

Phenomenal accelerator R&D facilities:

Accelerator Structure Test Area

NLC Test Accelerator

X-band Test Accelerator

End Station Test Beam

FACET

SPEAR-3

Linac Coherent Light Source

plus Shops and engineering staff to build what you need

Accelerator physics: small science experiments at big science facilities

Stanford Graduate Student Orientation, 9/20/2013

DOE Computing Resources:NERSC at LBNL - Franklin Cray XT4:

38,642 compute cores, 77 TBytes memory,

355 TflopsNCCS at ORNL - Jaguar Cray XT5:

224,256 compute cores, 300 TBytes memory, 2331 Tflops,

600 TBytes disk space

Local clusters and GPU machines

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Examples of Recent PhD Theses

• Dan Ratner, “Much Ado about Microbunching: Coherent Bunching in

High Brightness Electron Beams,”- Advisor: Axel Chao, 2011, Present position: Staff Scientist, SLAC

• Ian Blumenfeld, "Scaling of the Longitudial Electric Fields and

Transformer Ratio in a Non-Linear Plasma Wakefield Accelerator,“- Advisor: Alex Chao, 2009, Present position: Scientist, Modeling Group, Archimedes Inc.

• Neil Kirby, "Properties of Trapped Electron Bunches in a Plasma

Wakefield Accelerator," - Advisor: Alex Chao, 2009, Present position: Postdoc, Radiation Oncology Department,

UC San Francisco.

• Chris Sears, "Production, Characterization, and Acceleration of Optical

Microbunches," - Advisor: Robert Siemann, 2008, Present position: MPI Munich.

Stanford Graduate Student Orientation, 9/20/2013

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Summary

Accelerator R&D is a major effort at SLAC and there are a very broad range of potential

thesis topics

• Theoretical, simulation, and experimental• Many problems require effort all three

SLAC as a national lab has fantastic R&D facilities and a strong faculty and staff and

one of the best PhD programs

8 of the 20 American Physical Society Division of Particle Beam Thesis Award

recipients to date completed their graduate research at SLAC:

• Dan Ratner, a student of Alex Chao’s (2012)• Ian Blumenfeld, a student of Alex Chao’s (2011)• Dmitry Teytelman, a student of John Fox (2004) • David Pritzkau, a student of Bob Siemann (2003) • Boris Podobedov, a student of Bob Siemann (2002) • Shyam Prabhakar, a student of John Fox (2001) • Zhirong Huang, a student of Ron Ruth (1999) • Tor Raubenheimer, a student of Ewan Paterson (1994)

Come talk to us and don’t forget the tour: 2:00 pm from ROB parking lotStanford Graduate Student Orientation, 9/20/2013