Jerry Blazey NICADD/NIU Lab/University Accelerator R&D Partnerships (Models, Progress, & Opportunities) Gerald C. Blazey Northern Illinois Center for Accelerator

Jerry BlazeyNICADD/NIU

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


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)


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


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.


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

– collider studies (at SLAC)

• Outreach: surveys, citizen involvement


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.


“4-dim. cooling” sufficient for a neutrino factory.

“6-dim. cooling” required for a muon collider.

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Cooling Channel Design

Ignition source

LH2 under

Pressure

Quench site

A cooling cell with LH2 Absorbers, RF cavities and Solenoid Magnet


Photogrammetric studies of window (minimum heating, heat management, safety or burst tests)

Beam detection and profiling using bolometry (strips of material on the

absorber window that change resistance when

radiated.)

Focus has been oncomponent testing here the window.


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


Proton Linac Absorber Tests

Tests heat and current capabilities of components

ICAR: FTEs & Capital Equip.FNAL: FTEs & Site


Ground Stability at Fermilab• Coordinated by SLAC.

• NW purchased equipment & will participate.

• NUMI tunnel motion vs. depth measurements start in July.

Broadband Three-component Seismometers KS-2000

Portable Data Recorder DL-24


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 ofAcc. Phys.



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


• 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.

Dissertations


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


Plasma Wake-field Acceleration

Decelerated electrons down to ~3 MeV:

Accelerated electrons up to 20.3 MeV

Simulated energy spectrum

Principle:• e-beam punches structures in plasma• part of the beam is acceleratedParameters:• 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

14


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.


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


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


Topics/Dissertationshttp://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


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.


Notional Layout of Photoinjector(as envisioned by DESY)

Emittance ~1 micron, Bunch Length <270 micronsA long term facility to study beam physics, diagnostics

(not an endorsement)


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…


NICADD/ NIU Furnaces at Fermilab


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? Bedrock

Detector

Quads

PiezoMounts

LaserBeams


Inertial Anchor Concept Test

Platform Position vs Sample

nm

Sample Number10-meter interferometer

prototype


Feedback on Nanosecond Timescales

• 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

BPM

Kicker

ProcessorsControls


NLCTA Prototype Tests• Now running X-

band BPM & kicker to demonstrate feedback loop and measure latency.

• Will also migrate to engineering mockup

Feedback loop

Beam direction


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


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: [email protected]


ExampleID: 14 project_size: Medium skill_type: physicistshort project description: Damping Ring beam size monitorDetailed 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: [email protected]


ExampleID: 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: [email protected]


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


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 m).• Translation stage:20 mm travel, 2 m accuracy

11.0”

6.0”

CTR: Coherent Transition RadiationS: BeamsplitterM1: Mirror on Translation StageM2: Fixed Mirror, Semi-TransparentPM: Off-Axis Parabolic MirrorDET: Detector Module

An opportunity for otherdisciplines…


Interferometer OperationInterferogram Autocorrelation

Energy spectrum

(Hilbert transform of energy spectrum)

(Fourier transform)

Bunch Density

• Resolution of fine structure requires access to short wavelengths, • Existing interferometers average over many bunches, not single shots.


Electro-Optics

• Major Advantage: Noninvasive(Does not intersect beam.)

• Works via Pockels effect:- Electric field modifies

dielectric tensor;- Laser beam monitors

the modifications.

• Potential: Direct time-domainobservation of beam field.

BUT – Chamber wakefieldmust be small!

[M.J. Fitch, et al., Phys. Rev. Lett. 87, 034801 (2001)]


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


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


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.

Documents

Jerry Blazey NICADD/NIU Lab/University Accelerator R&D Partnerships (Models, Progress, & Opportunities) Gerald C. Blazey Northern Illinois Center for Accelerator