Lab/University Accelerator R&D Partnerships (Models, Progress, & Opportunities)

1. Lab/University Accelerator R&D Partnerships(Models, Progress, & Opportunities) Gerald C. Blazey Northern Illinois Center for Accelerator and Detector Design (http://nicadd.niu.edu) Northern Illinois University

2. Why? • An interesting field in its own right, with interesting challenges and questions. • Shortage of qualified physicists and resources committed to design of new machines and technologies. • For the linear collider in particular • Many of the unresolved technical issues are ideally suited for contributions from university groups. • HEP material and intellectual resources will be required. • Involvement of university will foster innovation, increase number of qualified individuals, leverage resources. (there is a well developed program for advanced concepts)

3. Representative Efforts • Illinois Consortium for Accelerator Research (ICAR). • The Fermilab/NICADD PhotoInjector (FNPL) • Single University/Laboratory Partnerships • The linear collider research topic database • The evolving consortia & working groups Opportunities

4. Illinois Consortium of Accelerator Research • 1999 - IIT organized university consortium to assist Fermilab w/ future technologies • 2000 - IIT, NIU, NW, UC, UIUC received funding from state of Illinois and NSF. • Current budget ~$2.5M/yr • which supports in whole or part ~25 faculty / scientists. • has resulted in three new accelerator faculty positions. • Groups loosely organized by Executive and Advisory Boards. • Pursue topics collaboratively and independently. • Almost all have backgrounds in HEP.

5. Activities • Neutrino factory feasibility studies I & II. • Proton driver physics and design studies. • Muon cooling (as part of MuCool Collaboration) effort instructive • Simulations and theoretical investigations • Absorber development and engineering • Fast Instrumentation • RF cavity mechanical design • Fermilab linac test beam • Linear Collider • Vibration studies • Photoinjector R&D for LC • g-g collider studies (at SLAC) • Outreach: surveys, citizen involvement

6. Comment on Structure • HEPAP has recommended advanced R&D. • The NSF funding for ICAR was part of a Muon Cooling joint proposal led by Cornell • Component Construction: ICAR, Mississippi • Theory: Cornell, MSU • Simulations: Indiana, Columbia, ICAR • 200 MHz SC Cavity: Cornell • The “subcontracting” structure successfully advanced project.

7. “4-dim. cooling” sufficient for a neutrino factory. “6-dim. cooling” required for a muon collider.

8. Cooling Channel Design Quench site LH2 under Pressure Ignition source A cooling cell with LH2 Absorbers,RF cavitiesandSolenoid Magnet

9. Photogrammetric studies of window (minimum heating, heat management, safety or burst tests) Focus has been on component testing here the window. Beam detection and profiling using bolometry (strips of material on the absorber window that change resistance when radiated.)

10. Dark current due in high gradient 800 MHz RF cavity within a solenoid destroys Plexiglas windows.

11. Proton Linac Absorber Tests Tests heat and current capabilities of components ICAR: FTEs & Capital Equip. FNAL: FTEs & Site

12. Ground Stability at Fermilab • Coordinated by SLAC. • NW purchased equipment & will participate. • NUMI tunnel motion vs. depth measurements start in July. Portable Data Recorder DL-24 Broadband Three-component Seismometers KS-2000

13. Fermilab/ Photoinjector Laboratory • An electron source at A0 location • Starting 2001 jointly operated by Fermilab/NICADD • Missions: • Investigation of beam physics • Development of beam diagnostics • Simulations • An international facility (ICAR: Chicago, Georgia, Michigan, Pennsylvania, Rochester, Fermilab, DESY, CERN, LBNL) • About 50% of the university types from HEP Training of Acc. Phys.

15. FNPL University Activities • Theses • Five completed • Three current • Beam Physics • Flat Beam Studies • Plasma Wakefield Acceleration • Laser Acceleration • Studies of Space Charge • Coherent Synchrotron Radiation Studies • Electron Beam Diagnostics • Interferometric bunch length measurements • Electro-optics • Open to new collaborators, ideas! Simulations

16. Dissertations • Completed • E. R. Colby, Ph.D., UCLA, 1997. Design, Construction, and Testing of a Radiofrequency Electron Photoinjector for the Next Generation Linear Collider. RF guns currently operating at Fermilab and DESY were constructed in the course of this work. • A. Fry, Ph.D., Rochester, 1996. Novel Pulse Train Glass Laser for RF Photoinjectors. Design and initial performance of the laser at the Fermilab photoinjector. • S. Fritzler, Diplomarbeit, Darmstadt, 2000. This thesis covers the first observation of channeling radiation in the high flux environment of A0, and extends observations as a function of bunch charge two orders of magnitude higher than any earlier measurement. • M. Fitch, Ph.D., Rochester, 2000. Electro-Optic Sampling of Transient Electric Fields from Charged Particle Beams. In addition to the discussion and measurement of wakefields induced by bunch passage through the photoinjector, further data on laser and injector performance is given. • J.-P. Carneiro, Ph.D., Universite de Paris-Sud, 2001. Etude experimental du photo-injecteur de Fermilab. This is a thorough documentation of the performance of the photoinjector, including comparison with the predictions of E. Colby. • Current • D.Bollinger, NIU, Plasma Acceleration • R.Tikhoplav, Rochester, Laser Acceleration. • Y-e Sun, Chicago, Flat Beams.

17. Flat Beams • LC specifications: x=300nm, y = 5nm. • A non-zero magnetic field at photo cathode imparts angular momentum to beam • Skew quadrupole triplet transforms round beam to flat beam • Key Question: How to optimize beam quality with flat-beam transformation? • Goal (eliminate e-damping ring): εy/εx~ 100 with εgeom~ 1 μm/nC. • Achieved to date: εy/εx ~ 50 with εgeom ~ 6 μm/nC

18. Plasma Wake-field Acceleration • Principle: • e-beam punches structures in plasma • part of the beam is accelerated • Parameters: • Charge: 6-8 nC • Bunch length: < 1 mm RMS • Plasma: L=8cm, 10 /cc density • Initial energy: 13.8 MeV • Acceleration gradient: 72 MeV/m Accelerated electrons up to 20.3 MeV 14 Simulated energy spectrum Decelerated electrons down to ~3 MeV:

19. Laser Acceleration of Electrons • Study the possibilities of using a laser beam to accelerate charged particles in a wave guide structure with dimensions much larger than the laser wavelength • The laser operates in the TEM01* mode which provides the largest possible longitudinal component of the electric field. • For 34 TW of laser power (the maximum that that can be supported by the structure) the accelerating field Ea=0.54 GV/m.

20. Bunch Compression • Coherent synchrotron radiation and other wake-fields generally complicate bunch compression, e.g., microbunching can arise • Energy fragmentation of compressed bunch as seen in FNPL: Beam Energy ~ 15 MeV Bunch Charge ~1 nC • Dynamics are sensitive to phase space input to the bunch compressor. • Careful measurement of input and output longitudinal phase spaces is needed  FIR interferometer to measure coherent synchrotron rad. E 

21. Simulations • Complication: Space charge, rf focusing “ruin” the linear round-to-flat transformation by introducing nonlinear forces. • Codes that include these nonlinear forces are, e.g.,: PARMELA, ASTRA, HOMDYN. • Canonical simplification: cylindrical symmetry ⇒ codes must be generalized! Authors of ASTRA, HOMDYN are working on generalizations. • Working to benchmark generalized codes against FNPL experiments. Ultimate goal is end-to-end simulation

22. Topics/Dissertations http://nicadd.niu.edu/fnplres.html • Electron-Beam Diagnostics • electro-optic crystal • Michelson interferometer • diffraction-radiation • deflecting srf cavity • Superconducting RF Cavities • “kaon-separator” (deflecting) cavity • “beam-shaper” (accelerating) cavity • RF Gun • high-duty-factor (srf?) • polarized beam • dark current and photocathode • Fundamental Studies of Space Charge & Coherent Synchrotron Radiation • Simulations

23. A High-Brightness Photoinjector • A collaboration modeled on large detector collaborations for the construction and operation of a high-brightness electron beam at Fermilab. • Five year construction, then operation. • Advanced beam research, diagnostics promotes university based research • Have encouragement from Fermilab & ANL. Site selection and timescales under discussion.

24. Notional Layout of Photoinjector (as envisioned by DESY) Emittance ~1 micron, Bunch Length <270 microns A long term facility to study beam physics, diagnostics (not an endorsement)

25. Example partnerships w/ Labs • NLC structures at Fermilab – NIU • Inertial anchor - University of British Columbia • Prototype intra-train beam-beam deflection feedback - Oxford • Many others….my apologies…

26. NICADD/ NIU Furnaces at Fermilab

27. Vibration Suppression R&D • U of B.Columbia, Tom Mattison + 2 students • Problem: • LC requires 2 nm vertical stability of beam & final quadrupoles. • Ground motion exceeds this at frequencies above 10 Hz. • Quads on cantilever supports amplify ground motion. • Possible Solution: Optical Anchor suggested by SLAC • measure quad positions w/ interferometers • correct positions/ with feedback. • SLAC provides equipment • First piece of engineering mockup • A comment: the quads are in the detector, contributions to this should clearly “punch” collaboration ticket, why stop there? Detector Laser Beams Piezo Mounts Quads Bedrock

28. Inertial Anchor Concept Test Platform Position vs Sample nm 10-meter interferometer prototype Sample Number

29. Feedback on Nanosecond Timescales Kicker • FONT Collaborators: Oxford HEP group (Phil Burrows + 2 postdocs + students), SLAC, KEK, CERN. • Problem: Beam offset must be 2 nm or less • Solution: Use feedback between beams to ensure deflection is zero. • The challenge: Nanosecond feedback on beam offset to correct train. • Simulation, design, construction at Oxford Processors Controls BPM

30. NLCTA Prototype Tests • Now running X-band BPM & kicker to demonstrate feedback loop and measure latency. • Will also migrate to engineering mockup Beam direction Feedback loop

31. The LC R&D List • Organized by Tom Himel with input from Dave Finley and Joe Rogers • Database of accelerator LC R&D in response to requests from the university community. • Contains a wide variety of priorities, project sizes, and needed skills. • NLC, TESLA, and generic accelerator R&D items are on the list • On Web: http://www-project.slac.stanford.edu/lc/Project_List/intro.htm

32. Example ID: 10         project_size: Medium      skill_type: Monte Carlo short project description: Background Calculation and Reduction in the IR. Detailed project description: There are many types of backgrounds: Halo muons, low energy e+e- pairs, synchrotron radiation. Use existing simulation tools (and perhaps write new ones) to calculate the background levels and to design shielding and masks to minimize it. Needed by who: NLC and TESLA     present status: In progress, help needed     Needed by date: 6/1/2005 ContactPerson1: Tom Markiewicz      WorkPhone1: 6509262668    EmailAddress1: twmark@slac.stanford.edu

33. Example ID: 14         project_size: Medium      skill_type: physicist short project description: Damping Ring beam size monitor Detailed project description: The beam height in the damping ring will be about 4 microns. We need to non-disruptively measure this on an individual turn in the ring. Traditionally this is done with a synchrotron light monitor. The spot here is so small that one must go to very short (x-ray) wavelengths to get the necessary resolution. We would like a conceptual design of some way to do this. It would then be evaluated whether a prototype is needed Needed by who: generic accelerator     Present status: need good idea     Needed by date: 6/1/2005 ContactPerson1: Marc Ross WorkPhone1: 6509263526     EmailAddress1: mcr@slc.slac.stanford.edu

34. Example ID: 38         project_size: Small      skill_type: Optics design short project description: beam profile monitor via optical transition radiation Detailed project description: In low intensity beam lines (injector), and possibly at the bunch length deflector cavity, measure the beam profile on a single bunch. A prototype system (with somewhat different parameters) is operating at the ATF. Needed by who: generic accelerator     present status: Prototype done     Needed by date: 1/1/2007 ContactPerson1: Joe Frisch      WorkPhone1: 6509264005     EmailAddress1: frisch@slac.stanford.edu

35. Other Selected Topics • Electronics standards – VME replacement • Production of polarized positrons. • Beam diagnostics • Laser wire beam monitor • Inteferometry (Bunch Compression/Frag.) • Optical Transition Radiation • Polarimetry • Luminosity Monitors • Remote Operations

36. A Diagnostic Interferometer • Optics diameter: 75 mm • Dimensions: 30cm x 15 cm x 15 cm • Frequency range: 3 cm-1 to 500 cm-1 (3.3 mm to 20 mm). • Translation stage: 20 mm travel, 2 mm accuracy CTR: Coherent Transition Radiation S: Beamsplitter M1: Mirror on Translation Stage M2: Fixed Mirror, Semi-Transparent PM: Off-Axis Parabolic Mirror DET: Detector Module An opportunity for other disciplines…

37. Interferogram Autocorrelation Energy spectrum Bunch Density (Hilbert transform of energy spectrum) (Fourier transform) Interferometer Operation • Resolution of fine structure requires access to short wavelengths, • Existing interferometers average over many bunches, not single shots.

38. Electro-Optics [M.J. Fitch, et al., Phys. Rev. Lett.87, 034801 (2001)] • Major Advantage: Noninvasive (Does not intersect beam.) • Works via Pockels effect: • Electric field modifies dielectric tensor; • Laser beam monitors the modifications. • Potential: Direct time-domain observation of beam field. BUT – Chamber wakefield must be small!

39. New Organizations • Framework for university involvement in detector & accelerator R&D on LC. • Currently : • 3 groups (Cornell, Fermilab, SLAC) • 2 funding agencies (NSF & DOE) • 1 Linear Collider • Relationships evolving • NSF groups naturally cluster under a single proposal submitted by Cornell? • DOE groups naturally cluster w/ Fermilab & SLAC under a individual or single proposals? • But work where convenient & communicate! • Proposals vetted by the USLCSG Working Groups

40. History • April 5th, Fermilab Meeting, 123 participants • April 19th, University Consortium for the Linear Collider @ Ithaca, 55 participants • May 30th, Linear Collider R&D Opportunities @ SLAC, 106 participants • June 27-30th , Santa Cruz • Linear Collider Retreat w/ Acc. R&D Sessions. • UCLC statements of interest • Joint Fermilab/SLAC meeting • September, NSF submission

41. Closing Comments • There are successful models for significant, university sponsored accelerator R&D • University based consortia. • Facility based collaborations. • Single groups w/ laboratory support. • We should broaden our definition of hardware contributions to include collider components. • There is ample opportunity to get involved, the skill set, project scopes are similar to HEP. • The new organizations offer opportunity! • Need new support, either from the universities or funding agencies – we need to move together.