The ILCTA_MDB Horizontal Test Stand for SRF Cavities

Andy Hocker

FNAL-TD

AEM, 25-JUN-2007

A. Hocker, 25-JUN-2007 AEM 2

Surface Processing

Cavity Fabrication

Vertical Testing

Cavity Dressing

Surface Processin

g

Horizontal Testing

Cold String Assembly

Pass!

Pass!

Fail!

Fail!

Horizontal Testing --- Context

A. Hocker, 25-JUN-2007 AEM 3

MDB: Lay of the Land

Horizontal test area for ILC

RF Hut Vertical Test area for HINS

A. Hocker, 25-JUN-2007 AEM 4

HTS Cave and RF Hut

300 kW klystron

charging supply modulator

WG switch

Horizontal Test Cryostat (HTC)

LHe/LN2 feed can

RF waveguide (1.3 and 3.9 GHz)

High power pulsed RF system (operated w/ CC2 for > 1 yr)

A. Hocker, 25-JUN-2007 AEM 5

Typical HTS test cycle

• Install cavity in HTC• Warm, off-resonance coupler conditioning

(high pulsed power processing)• Cooldown to 1.8 K• On-resonance conditioning of coupler/cavity

• Map out Q0 vs Eacc curve

• Test new widgets, etc.• Warmup• Remove cavity• Goal: ~10 day turnaround

Geophones (ILC CM vibration R&D)

A. Hocker, 25-JUN-2007 AEM 6

C22 prep (“dressing”)

Installation of cold part of input coupler at CAF-MP9 clean room

Cavity tuner installation

Ready to install in HTCInstallation of warm part of input coupler

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First measurement at HTS

• Room-temperature measurement of fundamental passband modes

• Zoom of “pi-mode” (accelerating mode)

A. Hocker, 25-JUN-2007 AEM 8

Status and plans

• Struggling with cavity cooldown– Identified a leaky liquid level probe as culprit, repairing

this week, go for cooldown again

• Finishing up RF distribution/interlock checkout– Installing WG shutters to allow for multi-cave (HTS and

CC2) configuration– Finishing up safety paperwork, final walk-through soon

• After RF checkout, begin commissioning– Execute HTS test cycle (~1 month)

• Declare open for business– First customer: FNAL third-harmonic (3.9 GHz) cavity for

DESY’s FLASH facility– 1.3 GHz cavities for first US-built ILC CM as schedule

allows