Challenges , Progress and P lans of SRF CH- Structures

LINAC AG • IAP • Goethe Universität Frankfurt

H. Podlech, IAP


H. Podlech, IAP

Challenges, Progress and Plans of SRF CH-Structures

Holger J. Podlech

Institute for Applied Physics (IAP)

University of Frankfurt

TTC MeetingJefferson Lab

November 5th-8th 2012


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CH-Structures

• Crossbar H-Mode-Structure

• H211-Mode

• Efficient DTL-structures for the low and medium energy range

• KONUS or EQUUS Layout


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f=360 MHzb=0.1 Ueff=5.5 MV

First CH-Prototype


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H. Podlech, IAP

Horizontal Test

Pick-up

Forwarded

Piezo signal


H. Podlech, IAP


H. Podlech, IAP

Learning Lessons From the First Prototype

Poor preparation possibilities (only on-axis) new cleaning flanges Long end cells for field

enhancement (additional drift) sloped end stems

Little space between stems for tuner and power coupler change orientation

New dynamic tuner without additional longitudinal space requirements


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H. Podlech, IAP

Bellow Tuner Static Tuners

Helium VesselPower Coupler

325 MHz CH-Cavity

b 0.1545

Frequency (MHz) 325.224

Cells 7

Length bl-def (mm) 505

Diameter (mm) 348

Ea (MV/m) 5

Ep/Ea 5.1

Bp/Ea [mT/(MV/m)] 13

G (W) 64

Ra/Q0 (W) 1248

RaRs (W2) 80000


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325 MHz CH-Prototype


H. Podlech, IAP


H. Podlech, IAP

Optimization of the Geometry of Superconducting CH-CavitiesCost, Construction Time, Fabrication Inaccuracies

Arrived in FrankfurtOctober 31st


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H. Podlech, IAP

325 MHz CH-Cavity: First Measurements


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H. Podlech, IAP

Design Position

Deviation from Design frequency:500 kHz < 0.2%

325 MHz Cavity: Static Tuners


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H. Podlech, IAP

Strategy to Hit the Operation Frequency

• Fabrication inaccuracy (Δf = 0.5 MHz)• Thermal shrinkage (Δf ≈ +400 kHz)• Pressure sensitivity (Δf ≈ +200 kHz)• Surface preparation (Δf = 6 kHz/mm)• Microphonics (Δf = ? Hz)• Lorentz Force Detuning (Δf = ? Hz)

• End cell offset 10 mm (Δf ≈ ±1 MHz)• Static tuners (Δf ≈ +1.3 MHz, -2.2 MHz)• Surface preparation (Δf = 6 kHz/mm)• Slow bellow tuners (Δf ≈ ±250 kHz)• Fast bellow tuner (Δf ≈ ± 1000 Hz)


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The MYRRHA ProjectMulti Purpose HYbrid Research Reactor for High Tech Applications


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The 17 MeV MYRRHA Injector

sc CH-4sc CH-3sc CH-2sc CH-1Parameter Unit Value

Frequency MHz 176.1

Cells --- 7-10

L tot mm 920-1130

Ueff MV 3.5-4.1

Ea MV/m 3.5-3.9

R/Q W 1600-2200


H. Podlech, IAP

Future GSI/FAIR Injector Complex

Parameter Unit

Mass/ Charge 6

Frequency MHz 216.816

Max. beam current mA 1

Injection energy AMeV 1.4

Output energy AMeV 3.5 – 7.5

Output energy spread AkeV ± 3

Length of acceleration m 12.7

Sc CH-cavities 9

Sc solenoids 7


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Parameter Unit CH-1

Beta 0.059

Frequency MHz 216.816

Gap number 15

Total length mm 687

Cavity diameter mm 409

Cell length mm 40.82

Aperture mm 20

Ua MV 3.369

Energy gain MeV 2.97

Accelerating gradient MV/ m 5.1

Ep/ Ea 6.4

Bp/ Ea mT/ (MV/m) 5.4

R/ Q Ω 3320

Static tuner 9

Dynamic bellow tuner 3

cw SHE-Linac Demonstrator

Helium vessel

Coupler flangePickup flange

Inclinedend stem

Tuner flange

Preparationflange


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Cryo Module cw SHE-Linac Demonstrator


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Setup for Beam Tests at GSI

108.4 MHz RFQ

108.4 MHz IH-Cavity

217 MHz Demonstrator


H. Podlech, IAP


H. Podlech, IAP

Thank you

Documents

Challenges , Progress and P lans of SRF CH- Structures