Challenges, Progress and Plans of SRF CH-Structures Holger J. Podlech Institute for Applied Physics (IAP) University of Frankfurt TTC Meeting Jefferson Lab November 5th-8th 2012

CH-Structures Crossbar H-Mode-Structure H211-Mode Efficient DTL-structures for the low and medium energy range KONUS or EQUUS Layout

First CH-Prototype f=360 MHz b=0.1 Ueff=5.5 MV

Pick-up Forwarded Piezo signal Horizontal Test

Learning Lessons From the First Prototype Little space between stems for tuner and power coupler  change orientation New dynamic tuner without additional longitudinal space requirements Poor preparation possibilities (only on-axis)  new cleaning flanges Long end cells for field enhancement (additional drift)  sloped end stems

325 MHz CH-Cavity Static Tuners Bellow Tuner Power Coupler 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 Power Coupler Helium Vessel

325 MHz CH-Prototype

Optimization of the Geometry of Superconducting CH-Cavities Cost, Construction Time, Fabrication Inaccuracies Arrived in Frankfurt October 31st

325 MHz CH-Cavity: First Measurements

325 MHz Cavity: Static Tuners Design Position Deviation from Design frequency: 500 kHz < 0.2%

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)

The MYRRHA Project Multi Purpose HYbrid Research Reactor for High Tech Applications Struckturen durchgehen Warum normalleitend / supraleitend CH-Design Solenoid-Design Ein Kryomodul

The 17 MeV MYRRHA Injector sc CH-4 sc CH-3 sc CH-2 sc CH-1 Parameter 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 Struckturen durchgehen Warum normalleitend / supraleitend CH-Design Solenoid-Design Ein Kryomodul

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 3.5 – 7.5 Output energy spread AkeV ± 3 Length of acceleration m 12.7 Sc CH-cavities 9 Sc solenoids 7

cw SHE-Linac Demonstrator Parameter Unit CH-1 Beta 0.059 Frequency MHz 216.816 Gap number 15 Total length mm 687 Cavity diameter 409 Cell length 40.82 Aperture 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 Helium vessel Coupler flange Pickup flange Inclined end stem Tuner flange Preparation flange

Cryo Module cw SHE-Linac Demonstrator

Setup for Beam Tests at GSI 217 MHz Demonstrator 108.4 MHz RFQ 108.4 MHz IH-Cavity

Thank you