New Developments in Injectors

1
New Developments in Injectors

• John W. Lewellen
• Argonne National Laboratory
• Northern Illinois University

2
Acknowledgements Thanks

• Prof. William Colson (Naval Postgraduate School)
• Prof. Todd Smith (Stanford)
• Dr. Lewis DeSandre and the Office of Naval
  Research
• Ilan Ben-Zvi, Sandra Biedron, Courtlandt Bohn,
  Charles Brau, John Corlett, Dimitre Dimitrov,
  Dave Douglas, Dave Dowell, Bruce Dunham, Massimo
  Ferrario, Klaus Floettmann, Rod Gerig, Kathy
  Harkay, Raquel Herald, Carlos Hernandez-Garcia,
  Dietmar Janssen, Kevin Jensen, Jom Luiten, Sue
  Mini, Nate Moody, Dinh Nguyen, John Noonan,
  Philippe Piot, Jamie Rosenzweig, Fernando
  Sannibale, John Schmerge, Michelle Shinn, John
  Smedley, Yin-e Sun, Gil Travish, Chun-Xi Wang...
• And others who are not on the above list ...
  please pardon my memory.

3
Activities List Accelerator Source Development
Compilation courtesy of Dr. Yin-e Sun, Argonne
Natl Laboratory
4
A Fundamental Flaw of This Talk

• Lots of activities, at lots of places (see prev.
  slide)
• I only have half an hour or so
• My options
• Tell many people places to stop doing
  interesting work
• I am not a funding agency
• Talk only about my own activities
• Choose highlights from a variety of places and
  apologize in advance to those I dont mention
  specifically or in depth
• Apologies in advance
• Todd Smith says you will enjoy it anyway

5
Question What Is An Injector, Anyway?

• An injector starts at the
• Cathode
• Drive laser
• Control room
• An injector ends at the end of the
• Gun
• Booster
• Merge optics
• Undulator
• Paper
• Pub

?
?
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I Want...

• Lower emittance
• higher gradient
• lower QE
• faster cathode
• lower bunch charge
• smaller emission radius

• Larger duty factor
• lower gradient
• higher QE
• lower bunch charge

• Higher charge per bunch
• higher gradient
• higher QE
• larger emission radius

Yes, I meant all at once...
7
Some Numbers
Light source numbers courtesy Kathy Harkay
(APS) IR-FEL numbers courtesy Bill Colson (NPS)
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Cathodes Theory and Modeling Progress
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Cathodes Experiments
Laser assisted electron emission
Ganter et.al., THCAU04, FEL2006
Moody et.al., THPP069, FEL2006
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Cathodes Experiments
Jlab Half-Cell
DESY Half-Cell
Courtesy John Smedley (BNL)
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Cathodes Experiments

• Superlattice photocathode study for JAEA DC
  photoinjector
• small initial momentum spread
• can optimize well / barrier layer spacing
• planning on continuing with NEA surface various
  Al fractions

633 nm
804 nm
633 nm
804 nm
Nishitana et.al., TUPPH07, FEL2006.
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Cathodes amplified
http//www.bnl.gov/cad/ecooling/DAP_principles.asp
www.agsrhichome.bnl.gov/AP/BNLapSeminar/2005_sept1
6.ppt
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Simulation
Courtesy Dimitre A. Dimitrov (Tech-X)
VORPAL also being modified for diamond amplifier
cathodes general extension possible
14
Cathodes (sort of...)
Courtesy Jom Luiten (TU Eindhoven)
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Bunch Generation
Idea Use pancake laser pulse, allow beam to
self-evolve to ideal ellipse Proposed by
Serafini in 1997 again by Luiten in 2004.
Being tried at SPARC
Rosenzweig et.al., AIP Conf. Proc. Vol 877, pp.
649 (2006)
16
Gun Designs
Quarter-Wave Coax Resonator Gun - LBNL
65-200 MHz, CW operation Beam dynamics similar
to DC guns for short pulses Dark current, ion
back bombardment, voltage breakdown similar to RF
guns Accommodates all cathode types
Courtesy Fernando Sannibale (LBL)
17
Gun Designs
Cathode Region Focusing Magnetic Mode FZR
Rossendorf
Courtesy Dietmar Janssen (FZR Rossendorf)
18
Gun Design Coax Coupler
Sekutowicz et.al., TESLA-FEL report 2005-09
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Gun Structures Under Construction
Courtesy FZR Rossendorf
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Beijing DC-SRF Hybrid Gun Tests
DC gun 1.5 cell structure ltIgt 270 mA en 5
mm Ek 500 kV
http//www.lns.cornell.edu/public/SRF2005/pdfs/ThP
34.pdf
Plans for a 3.5-cell cavity
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JLab Injector Test Stand
Courtesy Carlos Hernandez-Garcia (JLab)
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Cornell Injector Prototype
CPI variable-coupling input coupler

• Gun has been in operation for 1 year.
  Continuing longitudinal and transverse phase
  space measurements, HV processing and high
  current operation.
• Cryo system is nearly complete and is undergoing
  commissioning
• First horizontal cavity test in early July
• All injector cavities measured
• Klystrons and couplers are being delivered in
  stages until the fall.
• Preparing new area for injector in the fall
• Injector installation complete by end of 2007
• Injector commissioning early 2008

2-cell cavities for the ERL injector. Typical
performance 15 MV/m, Q gt 1x1010
Courtesy Bruce Dunham (Cornell)
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Brookhaven RHIC cooler test
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Our Hosts - ERLP
1st beam 16 Aug 06
http//www.4gls.ac.uk/ERLP.htm
25
Transport Theory
http//www.bnl.gov/npp/docs/RHICst06/Ben-Zvi20SnT
20review202006.pdf
26
Transport Simulation
Hajima, FLS 2006 http//adweb.desy.de/mpy/FLS2006/
proceedings/TALKS/WG212_TALK.PDF
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Transport
INSANE Injector Scheme for MADMAN
In collaboration with D. Douglas, JLab
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Technology Curves Drivers
Capabilities
Time
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Technology Curves and Drivers
ERL injectors
Capabilities

• Cu Pulsed RF guns
• 1st gen. linac-based light sources
• Linear colliders (maybe)

• DC thermionic guns
• SR injectors
• HEP machines

Time
Matured technology Slower rate of advance Highly
refined theory Incentive to launch
Initial development Basic theory Relatively poor
performance
Explosion of ideas Significant advances Low-hangi
ng fruit General acceptance
see The Innovators Dilemma, Clayton M
Christensen
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Conclusions