High-Brightness Electron Source: Expression of Intent

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High-Brightness Electron Source Expression of
Intent

• Courtlandt L. Bohn
• Northern Illinois University/Fermilab
• 14 May 2002
• (Presented to Fermilabs Accelerator Advisory
  Committee)

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Photoinjector Three (Pi3)

• A collaboration for the construction and
  operation of a high-brightness electron beam at
  Fermilab.
• Advanced beam research and machine development.
• The collaboration presently includes seven
  universities and three laboratories.
• An Expression of Intent submitted 02/11/02 to
  FNAL, ANL, LBNL, DOE, and NSF asking for
  encouragement to begin a design report.

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Motivation

• Fundamental beam and accelerator physics
• Wakefield laser acceleration.
• Bunch Compression.
• Flat Polarized Beams.
• Emittance Reduction.
• All of which will promotes growth and innovation
  through university training of accelerator
  physicists.
• Support for the new generation of linear
  colliders, FELs, and synchrotron radiation
  sources (1 micron emittance and 270 micron
  pulses)
• Demonstrate that injector specifications can be
  met.
• Platform to study generation of required beams.
• Develop expertise and infrastructure for LC
  efforts.
• Utilizes superconducting RF cavities and will
  foster Midwest and national development of the
  technology.

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Notional Layout of Photoinjector (as envisioned
by DESY cf. Conceptual Design of the XFEL
Photoinjector by M. Ferrario, K. Floettmann, B.
Grigoryan, T. Limberg, Ph. Piot)
Output Beam for FEL LC bunch charge is 3.2 nC
Energy 140 MeV ? 300 MeV
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Major Components

• Drive laser (provides a flexible pulse structure
  and train) with a CsTe photocathode (high QE).
• Emittance compensating solenoids.
• A DESY donated 1.3 GHz, 8 cavity cryomodule
  (immediate acceleration reduces emittance growth
  due to space charge).
• 3rd Harmonic superconducting RF section to
  correct non-linearities in longitudinal phase
  space.
• Four-dipole compression stage.
• Diagnostic matching section.
• A domestically developed cryomodule.

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Laser and Gun Requirements(based on FEL
requirements)
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Simulation Results Transverse Parameters
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Simulation Results Longitudinal Parameters
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Longitudinal Phase Space Before and After
3rd-Harmonic Section
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Phase Space After Bunch Compressor
AFTER
BEFORE
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Collaboration/Contributions

• Modeled on particle physics collaborations.
• Envision the laboratories (Fermilab, Argonne,
  LBNL, DESY) taking responsibility for larger
  projects.
• Infrastructure (Fermilab, ANL for chemistry)
• RF Gun (ANL), High repetition RF Gun (LBNL)
• Cryomodules (DESY, Pi3)
• 3rd Harmonic (Fermilab/LBNL)
• Compressor (Fermilab/ANL)
• While the universities (Chicago, Michigan, NIU,
  Northwestern, Pennsylvania, Rochester, UCLA ) .
• Contribute personnel (e.g., students!) to
  laboratory-based projects
• Take responsibility for smaller projects
• Simulations
• Laser
• Diagnostics

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Scope Support

• Scope
• Schedule Approximately a 5 year construction
  project.
• Cost A ball-park figure of 30M including
  MS, labor
• Collaboration working on (phased) schedule and
  cost
• Funding prospects
• Laboratory contributions will be crucial.
• Requested significant DoEd funding (3M ? 2 years
  6M)
• Expect continued state support through Illinois
  Consortium of Accelerator Research (ICAR). Total
  grant now 2.5M/yr would submit additional
  request.
• Will submit university proposals to DOE NSF
  which will increase university contributions.

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A Staged Scenario

• Some observations
• Optimistic about DoEd support
• Multi-laboratory interest
• Funding agencies cautious, partially associated
  with LC technology choice, partially with
  resource limitations
• Suggests an intermediate path compatible with LC
  choice
• Reduced initial cost
• Permits pursuit of beam physics
• Does not foreclose on future options.
• 1st Stage
• Upgraded FNPL at new Fermilab site
• Footprint infrastructure consistent with
  eventual expansion to 1 mm and 300 MeV
• Current gun, additional Tesla cavities or
  cryomodule, 3rd Harmonic cavity, new compressor
• 2nd Stage (a year or two later)
• Proposal for 1 mm and 300 MeV will benefit from
  additional time and experience
• Axially symmetric gun and second cryomodule

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Conclusions

• Pi3 will greatly strengthen HEP and the
  laboratories
• A small scale program already proven successful.
• A collaborative model to promote accelerator
  physics (will be opened to additional
  institutions).
• Strengthens accelerator physics infrastructure.
• Supports development of new technologies and
  machines.

The collaboration has requested laboratory
assistance to develop a design report by the end
of August.