Accelerator Research at SLAC Tor Raubenheimer Stanford Graduate Student Orientation September 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 electromagnetic fieldschargedparticles CRT’s  x-ray tubes  SRS  Large Hadron Collider Velocity = 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 2 Stanford Graduate Student Orientation, 9/20/2013

3 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 SLC HERA 4

Advanced Accelerator 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 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 meter Stanford Graduate Student Orientation, 9/20/2013 5

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, 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, Pa ge 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 ( ), Ron Ruth ( ) Department heads: Yunhai Cai and Cho Ng 8

9 Compact accelerators Developing new compact accelerator for Inverse Compton Scattering, FEL’s and Ultrafast e - Diffraction Gun Linac YAG, Laser Injection chamber Cecile Limborg Chris Adolphsen

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 Tantawi

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, Measured SPEAR bunch Calculated THzNonlinear dynamics: simulated & measured Stanford Graduate Student Orientation, 9/20/

12 Large Hadron Collider: Accelerator Research Stanford Graduate Student Orientation, 9/20/2013

13 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,

14 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, Senior Staff: Tom Markiewicz, Uli Wienands, Yunhai Cai, Stanford Graduate Student Orientation, 9/20/2013

15 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

16 LCLS Undulator Hall Stanford Graduate Student Orientation, 9/20/2013

Slide 17 Stanford Graduate Student Orientation, 9/20/2013 Linac Coherent Light Source II 1-km point Sectors of Linac (1 km) (with modifications) X-ray Transport Optics/Diagnostics New Underground Experiment Hall Bypass LCLS Linac In PEP Line (extended) New Beam Transport Hall SXR, HXR Undulators 2010: April- Critical Decision 0 approved 2011: October- Critical Decision 1 approved 2012: March- Critical Decision 3a approved 2012: August- Critical Decision : June- Critical Decision 3b 2018: Sept. First FEL Light 2019: 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 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

19 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, Stanford Graduate Student Orientation, 9/20/2013

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 Technology development 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 CompletedOngoingUnder development SLAC FEL R&D roadmap HXRSS Stanford Graduate Student Orientation, 9/20/

21 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 Tflops NCCS at ORNL - Jaguar Cray XT5: 224,256 compute cores, 300 TBytes memory, 2331 Tflops, 600 TBytes disk space Local clusters and GPU machines

22 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

23 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)Dmitry Teytelman David Pritzkau, a student of Bob Siemann (2003)David Pritzkau Boris Podobedov, a student of Bob Siemann (2002)Boris Podobedov Shyam Prabhakar, a student of John Fox (2001)Shyam Prabhakar Zhirong Huang, a student of Ron Ruth (1999)Zhirong Huang Tor Raubenheimer, a student of Ewan Paterson (1994)Tor Raubenheimer Come talk to us and don’t forget the tour: 2:00 pm from ROB parking lot Stanford Graduate Student Orientation, 9/20/2013