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Accelerator Research at SLAC. Tor Raubenheimer. Stanford Graduate Student Orientation September 20, 2012. What are accelerators?.
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Accelerator Research at SLAC Tor Raubenheimer Stanford Graduate Student Orientation September 20, 2012
What are accelerators? • Wikipedia: A particle accelerator is a device that uses electromagnetic fields to propel chargedparticles 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 Stanford Graduate Student Orientation, 9/20/2012
Accelerators at SLAC Particle Accelerators at SLAC FACET ASTA XTA Stanford Graduate Student Orientation, 9/20/2012
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 HERA SLC
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 Telecom and Semiconductor tools used to make an ‘accelerator on a chip’ New designs and materials push metal accelerator structures to the limit Extremely high fields in 1,000°C lithium plasmas have doubled the energy of the 3-km SLAC linac in just 1 meter Advanced Accelerator Research @ SLAC
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. Woodpile Structure Contact: Dr. Eric Colby, 926-3709; Dr. Joel England, 926-3706
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, 926-2951
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
Compact accelerators • Developing new compact acceleratorfor Inverse Compton Scattering, FEL’s and Ultrafast e- Diffraction YAG, Laser Injection chamber Linac Gun Cecile Limborg 926-8685 Chris Adolphsen 926-3560
Novel experimental beam dynamics Stanford Graduate Student Orientation, 9/20/2012
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 Accelerator Technology Research Undulator Mechanical Structure Electric Field Distribution For more info contact: Prof. Sami Tantawi 650-926-4454
SPEAR3 accelerator research Measured SPEAR bunch • 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 Calculated THz Nonlinear dynamics: simulated & measured James Safranek, 926-5438
Large Hadron Collider: Accelerator Research Stanford Graduate Student Orientation, 9/20/2012
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. Contact: John Fox, 926-2789 Stanford Graduate Student Orientation, 9/20/2012
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, x2789 • Senior Staff: • Tom Markiewicz, x2668 • Uli Wienands, x3817 • Yunhai Cai, x2935 Stanford Graduate Student Orientation, 9/20/2012
Linac Coherent Light Source (LCLS) • World’s first x-ray laser – a Free Electron Laser • Commissioned in 2009 and constantly advancing new concepts April 10, 2009 Stanford Graduate Student Orientation, 9/20/2012
LCLS Undulator Hall Stanford Graduate Student Orientation, 9/20/2012
Linac Coherent Light Source II Injector @ 1-km point Sectors 10-20 of Linac (1 km) (with modifications) 2010: April- Critical Decision 0 approved 2011: October- Critical Decision 1approved 2012: March- Critical Decision 3aapproved 2012: August- Critical Decision 2 2013: June- Critical Decision 3b 2018: Sept. First FEL Light 2019: Sept. Critical Decision 4 Bypass LCLS Linac In PEP Line (extended) New Beam Transport Hall SXR, HXR Undulators X-ray Transport Optics/Diagnostics New Underground Experiment Hall Linac'12, Tel Aviv, Sept. 2012
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) SASE spectrum Seeded spectrum Seeding + taper
SLAC FEL R&D roadmap LCLS-II injector LCLS-II completion 2019-20 2011-12 2013-14 2015-16 2017-18 HXRSS TWFEL X-ray seeding & brightness Soft X-Ray Self-Seeding ECHO-7 ECHO-75, laser phase error error HHG efficiency and control ASTA (Cathode, Gun) Injector R&D E-beam brightness & manipulation S0 ITF: advanced beam generation, high-energy compression and laser seeding Ultrafast techniques Temporal diagnostics & timing Attosecond x-ray generation THz & Polarization THz Polarization control HXRSS X-ray sharing Technology development Multi bunches, detectors, novel undulators, high-rep. rate Completed Ongoing Under development
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 DOE Computing Resources: NERSC at LBNL - Franklin Cray XT4: 38,642 compute cores, 77 TBytes memory, 355 Tflops NCCSat ORNL - Jaguar Cray XT5: 224,256 compute cores, 300 TBytes memory, 2331 Tflops, 600 TBytes disk space Local clusters and GPU machines Stanford Graduate Student Orientation, 9/20/2012
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, 9/20/2012
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) • ShyamPrabhakar, 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: 1:30 pm from ROB parking lot Stanford Graduate Student Orientation, 9/20/2012