Magnet R&D for Muon Beam Cooling at FNAL Alexander Zlobin Fermilab Muon Collider Design Workshop,...

Magnet R&D for Muon Beam Cooling at FNAL

Alexander ZlobinFermilab

Muon Collider Design Workshop,BNL

December 1-3, 2009

2 MC Design Workshop 12/03/09 Magnet R&D for Muon Beam Cooling at FNAL

ContributorsTD MSDN. Andreev, E. Barzi, V.S. Kashikhin, V.V. Kashikhin, M. Lamm,

V. Lombardo, M. Lopes, A. Makarov, D. Orris, A. Rusy, M. Tartaglia, D. Turrioni, G. Velev, M. Yu

APCYu. Alexahin, V. Balbekov, A. Janssen, K. Yonehara

Muons Inc.R. Johnson, S. Kahn, M. Turrene et al.

JLabV. Derbenev


Intro• Requirements for a Muon Collider magnet systems pose significant

challenges beyond the existing SC magnet technology. • The magnets require innovative design approaches, new

superconductors and structural materials, advanced fabrication processes and quality control methods, etc.

• Strong focused magnet R&D is absolutely necessary to support the MC feasibility study

• During last few years Fermilab magnet group actively contribute to different MC/NF R&D focusing on magnets for muon beam cooling

• This year we are also joining the efforts related to MC ring and IR magnets brining the experience gained during the development and production of NbTi IR quads for LHC, and successful HFM program developed Nb3Sn accelerator magnet technologies

• This presentation will focused on magnet R&D results and plans at Fermilab for muon beam cooling including– SC solenoids for 6D muon beam cooling – ultra-high field HTS solenoids for final cooling


6D cooling: Helical Cooling Channel

Multi-section HCC–Wide range of fields,

helical periods, apertures–Room for RF system and

absorber–Field tuning more

complicate at high fields HS concept (FNAL/Muons

Inc.)–Ring coils follow the helical

beam orbit producing all required field components

–Straight solenoid concept does not work for high-field/small-aperture sections

K. Yonehara, S. Kahn, R. Johnson et al.

V.S. Kashikhin et al. M. Lopes et al.


HS Technology R&D• Design studies show that it is very complex

magnet – significant magnetic forces and stored energy – must eventually incorporate RF system => large heat

depositions

• 4-coil Helical Solenoid Model Program⁻ Large-aperture HS for the first stage⁻ High-field HS for the final stage

• The program is partially supported by Muons Inc.

• Goals:– Select conductor– Develop and validate mechanical structure including

cryostat – Develop fabrication methods– Study and optimize the quench performance and

margins, field quality, coil cooling scheme, quench protection


4-Coil Model HSM01

• 4 single-layer SC coils with support structures and end flanges.

• Model OD is limited by the VMTF ID.• Rutherford-type SC cable (NbTi, SSC). • Inner and outer stainless steel rings

provide the coil support and intercept the radial Lorentz forces.

• At currents ~14 kA the fields, forces, and stresses in the 4-coil model are close to the long HS parameters.


HSM01 Quench Performance

The first 4-coil HS model HSM01 reached 85 % of its short sample limit => close to the design operation current.No temperature dependence => mechanically limited – why?


HSM01 Field Measurements

• Measured longitudinal and transverse field distributions agree well with predictions.

• Some differences in transverse field distributions are due to the uncertainty in coil position wrt coordinate system => further care will be taken on subsequent magnets to fiducialize the coil to facilitate field comparisons.


Thick epoxy

Voids

Coil 4 9 turns

Coil 3 9 turns

Coil 2 10 turns

Coil 1 9 turns

HSM01 Autopsy• HSM01 was cut in several

cross-sections to evaluate the model design and the quality of fabrication

Findings:• Irregular turn

position• Different turn

number• Poor epoxy

impregnation – voids

• Thick epoxy layers

• Insufficient coil and splice ground insulation


HSM02 NbTi 4-coil model 2

HSM02 baseline magnetic and mechanical design is the same as for HSM01.

Improved:• mechanical structure and insulation• cable geometry and insulation• coil winding and impregnation

proceduresSSC cable re-sized:• Thick side 1.600mm =>1.416mm• Thin side 1.375mm =>1.271mm• Avg. 1.413mm =>1.343mm• Width 12.36mm =>12.945mmCable test => no degradationHSM02 fabrication status:• Preparing for winding• Test in January 2010 0

200

400

600

800

1000

1200

1400

1600

1800

0 1 2 3 4 5 6 7 8 9 10B[T]

Ic[A

]

# 1 keystoned# 2 keystoned# 3 re-sized#4 re-sized


Next stepsNext models will address the issues in

preparation to the 6D HCC demo model:

Conductor:• MgB2 => low-field higher-temperature

margin or operation temperature • Nb3Sn/Nb3Al => higher fields higher-

temperature margin• Conductor stabilization => quench

protectionCoil winding: • hard-bend vs. easy-bend => operation

margin Cryostat and coil cooling:• Indirect coil cooling => simple cryostat • Cable-in-conduit – better cooling,

simple cryostatMgB2 6-on-1 cable (FNAL/HyperTech)

P. Lee, NHMFL


Hybrid HS Model

• Conceptual design study shows that a Hybrid HS may be needed for HCC

• The goal - develop mechanical design and technology for HTS section based on G2 tape/cable and its assembly with RF and Nb3Sn section

• The work is partially funded and performed in collaboration with Muons Inc.


Modeling HTS section with RF


HS rapid prototyping


Updated HCC parameters

Parameter listZ ±Δr ±Δp/

pb b’ bz ν κ λ Nμ εT εL ε6D

unit m cm % T T/m T GHz m mm rad mm mm3

Channel length

Full Width

Full width

@ ref

@ ref @ ref RF

1 0 15 22 1.3 -0.5 -4.2 0.325 1.0 1.0 388 20.4 42.8 129002 40 8 10 1.3 -0.5 -4.2 0.325 1.0 1.0 375 5.97 19.7 415.9

3 49 7 10 1.4 -0.6 -4.8 0.325 1.0 0.9 354 4.01 15.0 10.84 129 3 2.5 1.7 -0.8 -5.2 0.325 1.0 0.8 327 1.02 4.8 2.0

5 219 1.7 1.8 2.6 -2.0 -8.5 0.65 1.0 0.5 327 0.58 2.1 3.26 243 1.6 1.3 3.2 -3.1 -9.8 0.65 1.0 0.4 327 0.42 1.3 0.14

7 273 1.3 1.3 4.3 -5.6 -14.1 0.65 1.0 0.3 327 0.32 1.0 0.088 303 1.2 1.1 4.3 -5.6 -14.1 1.3 1.0 0.3 327 0.34 1.1 0.07

12/02/09 16MC Design workshop @BNL, K. Yonehara

Bz_max~4-14T => NbTi/MgB2 and Nb3Sn


6D cooling: HFOFO SnakeYu. Alexahin et al., PAC2009, PAC2007

HFOFO = Helical FOFO channel of alternating solenoids (ASOL)

FOFO-xyz = FOFO with xyz resonance phase advance per cell and one solenoid

HFOFO-60 (6 cell period, Q1) HFOFO-120 (6 cell period, Q2) - smaller beta @ absorbersFOFO-180 (2 cell period, Q1) - really low-beta FOFO:HFOFO-270 (4 cell period, Q3)

absorbers RF cavitiesalternating solenoids

RF, kHz

RF, cm

Emax, MV/m

P, MeV/c

L, cm

Rin, cm

Pitch, mrad

Bzmax, T

HFOFO-60 200 2x36 16 200 24 60 7 2.36 HFOFO-120 800 2x8 32 150 8 16 3 11.5 FOFO-180 100 ~10 7 15.5 HFOFO-270 800 2x8 32 100 8 16 3 18.5

Similar conductor and technologies as for HS


• Provide input on solenoid design and parameters for cooling channel based on HFOFO structure

• Coordinated specifications of magnet system for 6D cooling demo unit

Plans 21

HFOFO Status - Y. Alexahin 3rd MCDW BNL December 2, 2009

Search for the final stage HFOFO configuration (by IPAC10)

Front end with HFOFO (by April 2010 IDS meeting)

Determination of the number of stages and configuration for each stage (by the next MCDW)

Optimization of each stage parameters (2010-2012)

End-to-end simulation with matching between the stages (by 2012)


50 T Solenoid Conceptual Design

Nb3Sn

NbTi Basic Parameters

– Inner bore diameter 50 mm– Length 1 meter– Fields 30 T or higher

HTS materials

Key design issues:• superconductor type• Jc, effect of field direction in

case of HTS tapes• stress management • quench protection• cost Conceptual design: • hybrid coil design• coil sections

B

Coil radius, m

BSCCO


Strand and Tape Samples


HTS/HFS Conductor R&DMonitoring industry progress

to provide input to magnet design.

This includes studies of the engineering current density (Je) as a function of:

• magnetic field => up to 28 T (FNAL-NIMS);

• temperature => from superfluid He to LN;

• field orientation (for tapes)• bending strain;• longitudinal strain => new

fixture being commissioned;• transverse pressure =>

setup is available.

0

200

400

600

800

1000

1200

1400

1600

0 5 10 15 20 25 30 Applied Field, T

J E (4

.2 K

), A

/mm

2

SCS 4050 M3,349,fs (100A) (// B)NIMSSCS 4050 M3,349,fs(100A) (perp B)NIMS2G-348 (// B)2G-348 (perp B)NIMSBSCCO-2212 (OST)NIMSHermetic 1G (// B)NIMSHermetic 1G (par B)NIMSNb3Sn (High Jc, OST)Nb3SnNbTiSCS 4050-HF M3, 594, 1, bs (87A) (// B)SCS 4050-HF M3, 594, 1, bs (87A) (perp B)SCS12050 M3, 360, (230-240 A) (//B)SCS12050 M3, 360, (230-240 A) (perp B)


HTS cable R&DG1 cable:• In FY07-08 fabricated and

tested several Rutherford cable designs based on Bi-2212 strand (OST) – cabling technology– effect of cable PF

• Starting from FY2009 continue this work as part of National HTS program

G2 cable:• In FY09 started G2 Roebel

cable studies


Insert Coil R&DPresent focus on single and double-layer

pancake coils based on HTS tapes.~20 single and double-layer pancake coils

made of YBCO and Bi-2223 were built and tested in self-field and external solenoid tape splicing techniques, effect of

coil impregnation, coil preload A modular HTS Insert Test Facility to test

up to 14 double-layer pancake coils inside the 14T/16T solenoid (B>20 T)

For the second phase of the coil program, larger multi-section HTS coils will be designed, fabricated and tested to achieve higher magnetic field and force levels.


Summary

• The midterm goal of the Fermilab’s accelerator magnet R&D program is to support the Fermilab’s and national efforts towards the demonstration of feasibility of a Muon Collider, with the long term goal of building this machine on Fermilab site.

• Fermilab’s magnet program is making progress in all key directions– Magnet design studies– Technology development– HTS material R&D

• We collaborate with DOE labs, industries and Universities through National HTS Conductor program, SBIR and other programs.

• Our efforts are coordinated with National MAP R&D plan• Adequate and stable funding is critical for the successful magnet R&D

– at the present time the program funding is provided by MCTF and HFM Program with contribution from Muons Inc.

– after MAP approval by DOE we will still need substantial contribution from core program and other sources

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Magnet R&D for Muon Beam Cooling at FNAL Alexander Zlobin Fermilab Muon Collider Design Workshop,...

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