FEL Research at the Naval Postgraduate School
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FEL Research at the Naval Postgraduate School Joe Blau, John Lewellen, Bill Colson Physics Department Naval Postgraduate School XFEL Workshop, LBNL, Berkeley, CA, October 23, 2008. U.S. Marine. Other U.S. Corps. 5%. 13%. International. U.S. Navy. 19%. 42%. NPS Students: 1,556

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FEL Research at the Naval Postgraduate SchoolJoe Blau, John Lewellen, Bill Colson Physics DepartmentNaval Postgraduate SchoolXFEL Workshop, LBNL, Berkeley, CA, October 23, 2008


Naval postgraduate school

U.S. Marine

Other U.S.

Corps

5%

13%

International

U.S. Navy

19%

42%

NPS Students: 1,556

from 88 nations

U.S. Army

7%

U.S. Coast

U.S. Air

Guard

Force

<1%

14%

Naval Postgraduate School

100 Years of Graduate Military Education

  • 1909: Founded at the U.S. Naval Academy to provide the Fleet with a focused Engineering Program

  • 1951: Moved to Monterey, CA


NPS Physics Department

  • ~30 PhD faculty: Teaching and Research Faculty

  • ~80-100 Masters students onboard, ~5% PhD

  • Masters in Applied Physics (2 years) with Thesis

  • ~$7M/year research dollars: ONR, NSF, DOE, NAVSEA,…

  • ~$2M/year separate teaching budget

  • Areas of research specialization are varied, but include:

    • acoustics

    • weapons and weapons effects

    • free electron laser and railgun technologies

    • electro-optics and sensor physics

    • basic physics research

  • Large (~hundreds) civilian PhD initiative beginning now

  • U.S. civilians headed to industry and national laboratories


  • Current nps fel group

    Faculty

    Bill Colson

    Joe Blau

    Bob Armstead

    Pete Crooker

    John Lewellen

    Technical Support

    Bill Armstrong

    Don Snyder

    Rich Swent

    Other Support

    Raquel Herold (admin)

    Eric Adint (computer)

    Ph.D. candidates

    LCDR Sean Niles

    CDR Ken Ferguson

    Master’s candidates

    LT Robert Neuerman

    LT Robert Edmonson

    LT Ben Wilder

    LTJG Aaron Zimmer

    LT Justin Jimenez

    LT Samuel Hallock

    Visiting Faculty

    Todd Smith (Stanford)

    Bill Graves (MIT)

    John Noonan (Argonne)

    Current NPS-FEL Group


    Nps fel plans
    NPS-FEL Plans

    • NPS-FEL vault & lab space will be completed soon

      (promised for end of CY08)

    • Cathode-related work on SCA injector

    • New booster / injector development in progress

    • Facilities build-out and population starting

    • Continue / Initiate NPS internal collaborations

    • NPS-FEL team needs to grow

      • already attracting more students

      • need to hire post-docs and staff researchers


    Plans for fel laboratory
    Plans for FEL Laboratory

    • NPS internal funding

      • $1.2M for building rehab (starting up)

      • $250k for MW power upgrade (completed June ’08)

    • NAVMED safety approvals

      (start early ’09)

      • radiation

      • laser

    • Infrastructure installation

      (throughout ’09)

      • Cryogenic system

      • RF power sources

      • Interlock and other safety systems

    • Control system installation / expansion

    • Cathode experiments with SCA gun

    • QW booster cavity installation & testing

    • Start linac systems layout, installation & testing


    Plans for the guns
    Plans for the Guns

    • SCA Injector (230 kV DC) (through late ’09)

      • Photothermal cathode testing (w/ NRL, UMD)

      • Field emitter cathode testing (w/ Vanderbilt)

    • Niowave QW SRF gun (1.5 MeV, 500 MHz) (late ’09)

      • System on order – funds committed ($950k)

      • Gradient standoff & cavity commissioning

      • “Can it make beam?” testing

    • Start looking at loadlock and cathode systems (through ’09)


    Plans for the linac
    Plans for the LINAC

    • In-line linac configuration (late ’08 – mid ’09)

      • design

      • begin component purchase / build / install

    • Recirculator configuration (mid ’09)

      • design

      • redesign

    • Start measuring & characterizing our existing magnets (early ’09)

    • Potential: Modify cryomodules for local liquefaction (mid- to late ’09)


    Nps fel 4d simulation
    NPS FEL 4D Simulation

    • Cluster handles ~100 z-slices in optical pulse

    • Each slice follows (x,y) evolution of electrons and light

    • Typical simulation has 3x106 electrons, 16x106 sites

    • Fields and electrons evolve self-consistently in (x,y,z)

    • Electron pulse slips back relative to optical pulse

    NPS FEL Cluster

    optical

    wavefront

    a(x,y,z)

    optical pulse

    electrons

    z-slices

    electron

    phase space

    =1

    =0


    Simulation method
    Simulation Method

    • 4D multimode simulation in (x, y, z, t)

    • Parallelized to run on cluster computer

    • Uses self-consistent Lorentz-Maxwell equations

    • Includes betatron motion of electrons

    • Includes pulse slippage and optical diffraction

    • Linear or step-tapered undulator

    • Stability effects: shift and tilt electron beam

    • Expanding coordinates propagate light to first optic


    Brookhaven SDL FEL Amplifier

    L = 10m

    Electron Beam:

    Energy: Eb = 101 MeV Trans. Emit: n = 4 mm-mrad

    Radius: rb = 0.21 mm Long. emit: l = 65 keV-ps

    Bunch charge: q = 0.35 nC Peak Current: Ipeak = 230 A

    Bunch Duration: tb = 1.5 ps Energy Spread = 0.1%

    Undulator (NISUS):

    Period: 0 = 3.89 cm Number of periods: N = 256

    Length: L = 10 m Undulator parameter: Krms = 0.78

    Seed Laser:

    Wavelength: = 0.79 m Peak power: Popt = 4 kW

    Pulse Duration: topt = 4.2 ps


    Sdl fel comparison to experiment
    SDL FEL: Comparison to Experiment

    Electron beam kinetic energy: Eb = 100.9 MeV (at resonance, 0 = 0)

    Extraction:  = 0.13%

    Final optical pulse energy: Eopt = 44 J

    (experiment: 43 J)

    Note final optical pulse shape is nearly flat-top

    Induced energy spread:

    / ≈ 2%

    Transverse profile shows higher-order modes


    Sdl fel comparison to detuning experiment
    SDL FEL: Comparison to Detuning Experiment

    Electron beam kinetic energy increased by 0.4%

    Eb = 101.3 MeV (0 = 12)

    Final optical spectrum is broader; note sideband

    Extraction:  = 0.37%

    Final optical pulse energy: Eopt = 130 J

    (experiment: 134 J)

    Induced energy spread:

    / ≈ 2%


    Plans for simulation
    Plans for Simulation

    • Continue work on 4D FEL amplifier simulation

      • Improve methods for optical mode description (Laguerre and Hermite-Gaussian mode expansions)

      • Develop models for spontaneous emission / start-up noise to model SASE FEL designs

      • More comparisons to experiments, theoretical models and other simulations

    • Develop 4D FEL oscillator simulation

      • Already have 3D model, doesn’t include pulse effects

    • Study alternate approaches, e.g. ring resonator and RAFEL

    • Develop start-to-end model including accelerator, beamline and recirculation

      • Interface with existing particle beam codes (e.g., Parmela, elegant)


    Collaborations map

    AES

    LANL

    Varian / CPI

    Diagnostics

    JLab

    Niowave

    Cryoplant

    Argonne

    INP-FEL primes

    Fermilab

    LINAC Systems

    Industry

    Livermore

    Control System

    NIU

    UMD

    National Labs

    RF Systems

    MIT

    UT

    Drive Lasers

    Stanford

    Port Hueneme

    Vanderbilt

    Gun Systems

    Pax River

    UCLA

    NRL

    NPS-FEL

    Navy Labs

    Academia

    Collaborations Map


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