MuCool Activities

1
MuCool Activities

• Muon Cooling RD
• ISS Meeting at KEK
• January 24, 2006
• A. Bross

2
MuCool

• Mission
• Design, prototype and test all cooling channel
  components
• 201 MHz RF Cavities, LH2 absorbers, SC solenoids
• Perform high beam-power engineering test of
  cooling section components
• Support MICE (cooling demonstration experiment)

• Consists of 9 institutions from the US and Japan

RF Development ANL Fermilab IIT JLAB LBNL Univ.
of Mississippi
Absorber RD Fermilab IIT KEK NIU U.
Mississippi U. Osaka
Solenoids LBNL
3
MuCool

• RD Focus of MuCool
• Component testing Fermilab
• High Power
• Both RF and Beam

4
MuCool Test Area

• Facility to test all components of cooling
  channel (not a test of ionization cooling)
• At high beam power
• Designed to accommodate full Linac Beam
• 1.6 X 1013 p/pulse _at_15 Hz
• 2.4 X 1014 p/s
• 600 W into 35 cm LH2 absorber _at_ 400 MeV
• RF power from Linac (201 and 805 MHz test stands)
• Waveguides pipe power to MTA

5
MTA Hall
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MTA

• The MTA is the focus of our Activities
• RF testing (805 and 201 MHz)
• Installation/commissioning of Cryo-Infrastructure
• High pressure H2 gas-filled RF
• LH2 Absorber tests
• High Intensity Beam
• Will start with low intensity

7
MTA Cryo-Infrastruture
Compressor Installation and piping are complete
Heat exchanger
Towards Experimental Hall
Needed for Magnet Operations and LH2 Absorber
Tests

• Compressor Room
• Two 400 HP 2-stage oil injected screw compressors

• Refrigerator Room
• Tevatron satellite refrigerator to be operated
  on 5 K mode and 14 K mode (3 DE, 3 WE)
• Helium and nitrogen Dewar

8
MTA High Intensity Beam

• 400 MeV beamline for the MTA has been designed
• Under Craig Moore
• External Beams Department
• Developed Engineering Design
• Cost
• Schedule
• Safety Analysis
• Linac Area and Beamline
• Shielding Assessment for MTA
• The current beam line design allows for Linac
  diagnostic
• High-Quality emittance measurement
• Our goal is to bring Low Intensity to the MTA as
  soon as possible

MTA
9
MTA Near Term Test Program

• 805 MHz Pill Box preparation complete 11/30/05
• Low power testing and conditioning begins
• Currently have reached approximately 1MV/m
• 805 MHz high-power testing begins 1/1/06
• TiN coated curved Be windows tests
• Currently at 18 MV/m (1 MW power)
• Various B field configurations
• 201 MHz cavity ready for testing 2/1/06
• LH2 Absorber test 3/06
• Second phase of testing with KEK convective
• absorber
• This is dependent on new safety review

10
RF Cavity R and D

• ANL/FNAL/IIT/LBNL/UMiss

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Fundamental Focus Of RF RD

• Study the limits on Accelerating Gradient in NCRF
  cavities in magnetic field
• However
• We believe that the behavior of RF systems in
  general can be accurately described (predicted)
  by
• Tensile strength of the material(s) used in the
  cavity fabrication (T)
• Local surface field enhancements (beq)
• Esurf Ö(2T/eo)/beq
• This applies to all accelerating structures
• Follows universal curve

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Phase I of RF Cavity Closed Cell Magnetic Field
Studies (805 MHz)

• Data seem to follow universal curve
• Max stable gradient degrades quickly with B field
• Sparking limits max gradient
• Copper surfaces the problem

Gradient in MV/m
Peak Magnetic Field in T at the Window
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Phase II of 805 MHz studies

• Study breakdown and dark current characteristics
  as function of gradient and applied B field in
  Pillbox cavity
• Curved Be window Test
• TiN coated
• System now conditioning
• _at_18MV/m (1 MW)
• Study
• Max stable gradient as function of B field
• Dark current and breakdown
• Cavity stability as funciton of power
• Button test
• Evaluate various materials and coatings
• Allows for quick turn around no conditioning
  needed

14
RF RD 201 MHz Cavity Design

• The 201 MHz Cavity is now in the MTA ready for
  test
• Final hook-up should be starting this week

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201 MHz Cavity Hookup
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Local Electrode Atom Probe (LEAP) Tomography

• Atom probe experiments in collaboration with
  Northwestern U.
• Prof. David Seidman Jason Sebastian
  (Northwestern),
• P. Bauer, C. Boffo (FNAL), J. Norem (ANL)
• High Gradient material studies relevant to both
  NCRF and SCRF ILC, Neutrino Factory, Muon
  Collider, CLIC.
• Surface microstructure
• Surface contamination (oxides etc.)
• Breakdown and Dark Currents
• Data from these tests expand our knowledge of
  breakdown phenomena, will allow us to develop a
  detailed model of the physics of breakdown in
  cavities, and can provide a guide for
  materials/fabrication procedures for RF cavities

Atom Probe Data from Nb sample _at_ 10 GV/m
Modeling Fracture
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Absorber R and D

• IIT/KEK/NIU/Osaka/UMiss

18
Absorber Design Issues

• 2D Transverse Cooling
• and
• Figure of merit MLRdEm/ds
• M2 (4D cooling) for different absorbers

H2 is clearly Best - Neglecting Engineering
Issues Windows, Safety
19
Absorber Design Issues

• Design Criteria
• High Power Handling
• Study II few 100 W to 1 KW with upgraded
  (4MW) proton driver
• 10 KW in ring cooler
• Must remove heat
• Safety issues regarding use of LH2 (or gaseous
  H2)
• Window design paramount
• H2 containment
• Proximity to RF adds constraints (ignition
  source)
• Two Design Approaches
• Convective Cooling
• Shown to the right
• Forced flow
• High power handling

H2 implies engineering complexity
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Forced-Flow Absorber

• Heat removed with external heat exchanger
• LH2 pumped from absorber to heat exchanger
• Nozzles in flow path establish turbulent flow
• Simulation via 2D and 3D FEA
• Preliminary engineering design for implementation
  in the MTA
• Have taken possession of cooling loop heat
  exchanger from SAMPLE experiment _at_ Bates/MIT
• Prototype Absorber manifold has been fabricated

21
MuCool Plans for the Coming Year

• After a long pause due to the loss of our 805 MHz
  RF test facility in Lab G at Fermilab, we are
  starting up again
• 805 MHz RF studies
• Be Window tests
• Materials tests
• Surface treatment
• Use information from LEAP studies
• Start 201 MHz RF test program
• 805 MHz testing likely to continue interleaved
  with 201 testing
• Second round of tests with KEK convective
  absorber
• Complete MTA cryo infrastructure installation and
  commission system
• Start installation of 400 MeV beam line from
  Linac
• Have the capability for low-intensity experiments

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The MuCool Test Area Potential

• The MuCooL Test Area is becoming a tremendous
  resource
• It has the potential to provide a Unique
  (World-wide) RD facility
• Multi-frequency RF test capability (NC and SC)
• Hydrogen Safety
• Absorbers
• Gas-filled RF cavities
• Cryo-infrastructure (LN, high capacity LHe)
• High-Intensity beam