spx0 cavity and cryomodule systems wbs 01.02.01.03.05

SPX0 Cavity and Cryomodule Systems

WBS 01.02.01.03.05

Genfa WuSRF ScientistASD/RF

SPX0 Review23-24 August 2012

SPX0 Review of the Advanced Photon Source Upgrade Project 23-24 August 2012

For the JLAB/ANL/SLAC Collaboration Team

Outline WBS Scope of this system Requirements Design Interfaces Risks considered (Fault Analysis) Summary

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Cavity and Cryomodule System Scope

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Fabricate and test major cavity system components. Fabricate, test and install a single cryomodule containing two

SRF deflecting cavities (MARK II) with LOM/HOM waveguide dampers and tuners in Sector 5 of the APS storage ring.


Cavity and Cryomodule System Requirements

Discuss requirements, PRD, ESD as exist. What KPP’s are supported (if applicable) Discuss the technical goals / science (if appropriate)

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SPX0 Physics

To demonstrate operation of two fully-powered independently-controlled superconducting deflecting cavities with beam, including quantitative measurements of their impact on the beam. This test will require low-level rf control, high-power rf, interlock systems, timing and synchronization systems, cavity alignment, beam diagnostics, controls, and beam feedback.

To demonstrate synchronization of a beamline laser with the deflecting cavities at the sub-ps level.

When operated in phase, the two cavities will increase vertical beam size everywhere around the ring, and therefore in this configuration will not be compatible with normal user operation. The tests will only be conducted during storage ring beam study periods. When operated in opposite phases with zero net deflecting voltage, no significant effect on the beam is expected, so that the cavities could be operated and tested during user operations. However, this mode of operation will need to be confirmed as acceptable for the user operations first.

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SPX0 Physics Requirement Document


SPX0 Main ParametersQuantity Value

Electron beam current 100 mA

Number of cavities 2

Total voltage 1.0 MV

RF Frequency 2815.486 MHz

Cavity tunability 200 kHz

Source tunability 1.5 kHz

Operating temperature 2 K

Longitudinal non-deflecting mode impedance <0.44 M-GHz

Horizontal non-deflecting mode impedance <1.3 M/m

Vertical non-deflecting mode impedance <3.9 M/m

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SPX0 Physics Requirement DocumentSPX0 Cryomodule Engineering Specification Document


Cryomodule Engineering Specification* (1)

Cavity nominal operating deflecting voltage 0.5 MV with Q0 ≥ 1e9 Cavity Qext = 1e6, RF source 5 kW Cavity Tuner: 2815.486 MHz ±200kHz, resolution < 40Hz Cavity alignment:

– X : ±0.5 mm, Y : ±0.5 mm, Z : ±1.0 mm Cryomodule alignment:

– X : ±0.5 mm, Y : ±0.2 mm, Z : ±1.0 mm Cryogenic total heatload goal

– 2 K heatload < 50 W (+/-5 W)– 80 K heatload < 260 W

Profile needs to fit APS tunnel (Sector 5 envelop)– 73.4” flange to flange– Maximum height from beam line < 40” – Floor to beam < 52.52”

Advanced Photon Source Upgrade (APS-U) project

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*See Engineering Parameters Table for complete details

Cryomodule Engineering Specification* (2) Bellows

– Inter-cavity rigid connection– Warm to cold transition bellows

• Unshielded• Longitudinal movement ±0.5 mm, transverse movement ±1.0 mm

Magnetic shielding: ≤ 5 mili-Gauss Dampers

– External LOM load (2 kW)– Internal HOM load ( 500 W, water cooled)

Windows– LOM broad band, 5 kW average power– FPC broad band, 5 kW - 20 kW average power

Interfaces: water, vacuum, RF, instrumentation.

*See Engineering Parameters Table for complete details


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Deflecting Cavities

SPX0 Review of the Advanced Photon Source Upgrade Project, 23-24 August 2012

HOM Damper

LOM Damper

HOM Damper

CCA3 design

CCA3 fabrication

Input Coupler

Specification

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Deflecting Cavity Performance


CCB1 is fully satisfied to the spec

CCA2 achieved gradient requirement

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ls P

VR2

2

GHzMfR ps 44.0*

Stability Threshold

Monopole Impedance

Monopole Stability Threshold

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2

20

rkP

VR

l

rrt

mMRt /3.1

mMRt /9.3 Horizontal dipole

Vertical dipole

Dipole Stability Threshold

Vertical Dipole Impedance

Stability Threshold

Stability Threshold

Horizontal Dipole Impedance

Total HOM/LOM power for Mark-II: <0.5/1.8kW for APS 200mA, 24 beam bunch mode

Impedance Calculations for Single Cavity

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Impedance Calculations for Multiple Cavities

The propagating modes up to 5 GHz are also damped to meet the desire requirements. There is no trapped mode between the cavities.

Liling Xiao et al., Higher Order Modes Damping Analysis for the SPX Deflecting Cavity Cryomodule, IPAC 2012

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SPX0 Helium Vessel Design


Helium Return

Helium Supply

Tuner Attachment Points

Nitronic Rod Mount

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Stress Analysis of a Dressed Cavity


With the small bellows design, the peak stress in warm CC-A3 cavity dropped to 6,100 psi, which is below the allowable of 6,310 psi. (Conservative to design to peak stress.)

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SPX0 Tuner Design


SPX Tuner Design Specifications 12Gev Upgrade SPX

C100 Style CavityCC-A3

3.5mm wall

Tuning Sensitivity kHz / mm 310 9000Stiffness lbs / in 9851 170000

Deflection required for 200 kHz frequency shift

um 645 22

Force required for 200 kHz frequency shift lbs 250 149

Stepper Motor Resolution Steps/rev 200 800Harmonic Drive Ratio 100 100

Ball Screw Pitch mm/rev 5 2

Resolution from Stepper**full step Hz / increment 13.6 31.6half step Hz / increment 6.8 15.8

quarter step Hz / increment 3.4 7.9

Piezo Range(drive axis) um 60 60

(cavity axis) kHz 3.3 75.8Piezo Resolution

(drive axis) nm 0.13 0.13(cavity axis) Hz 0.01 0.16

* - SPX numbers taken from J. Liu FEA** - Stepper controller enables up to 1/256 microstepping. As smaller steps are used there is a tradeoff of resolution for torque. Testing is required to determine what level of micro-stepping is achievable.

Cavity Related Info*

Tuner Related Info

Tuning Range• +/- 200 kHz

Tuning Resolution• 40 Hz

Rapid Detuning• 3 kHz• < 1msec

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SPX0 Tuner Design Status: Cavity Measurements

SPX Cavity (CCA3-1) Exercised in Modified C100 Tuner Test Stand – Cavity instrumented with 4 strain gages– Axial Force, Length, and Frequency measured as

cavity stretched


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SPX Tuner Design Status: Cavity Measurements


Tuning Sensitivity (Mhz/mm)*

Cavity Stiffness (klbs / in)**

Predicted 12.2 113.5Measured 13.0 101.6

* - The tuning sensitivity with a He vessel is expected to decrease by 26%** - The stiffness with a He vessel is expected to increase by 12%

Modeling Validated

Horizontal Test Stand

18Advanced Photon Source Upgrade (APS-U) project

Horizontal cavity test 5 kW amplifier 50 W Cooling @2K Analog and Digital RF

Horizontal test of a dressed cavity is scheduled in October 2012

ATLAS test area

Advanced Photon Source Upgrade (APS-U) projectSPX Review, March 3-4 2011

19Advanced Photon Source Upgrade (APS-U) project

Cavity Layout for SPX0 Alignment


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One room temperature shielded beam line bellows each side (not shown)

Bellows adjustment and beam steering ranges


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Transition bellows allows +/- 0.5mm Beam line bellows allows +/- 1.0 mm Beam steering during beam studies allows +/- 0.66mm

If a cavity misses beam line by 0.5 mm, adjusting cryomodule alone can bring cavities back to perfect alignment of electric centers.

Adjustment bounding boxes

Alignment Progression


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1. Wire stretch on CMM allows relation of alignment balls to electrical center line of cavity

2. Comparison to pre-HV measurements provide reference

3. Create custom spool piece to link cavities and Use fiducials + wire stretch to confirm that pair electrical center matches combination of pair centers

4. Use alignment balls to transfer fiducialization from beam line to space from on rabbit ears

30 um error each time fiducialization transferred

Courtesy of Josh Feingold

1 2 3

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JLAB Stretched Wire Measurement


23Slide from Josh Feingold

Low Impedance Unshielded Bellows


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BellowsBunch length [mm]

Nominal loss factor Kloss [mV/pC]

Shielding

APS 3 64 YesSOLEIL 3 20 YesSPEAR3 3 67 YesNSLS-II 3 18 YesAmerican BOA IV

3 455 No

American BOA IV

10 1.517 No

Loss Factor: 1.517 V/nC

Prototype bellows are being fabricated

Materials: Copper plated Stainless Steel or Phosphor copper alloy

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CLEAN ROOMCAVITY STRING

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COLDMASS

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COLDMASS

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CRYOMODULE ASSEMBLY

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SPX0 Cryogenic Design

SPX0 will use existing CEBAF prototype end cans – No 5K circuit

• 5K heat load will be sunk to 2K with heat straps added to stabilize thermal loads as required (waveguides, beamtubes)

– Heat exchanger will be external to cryostat SPX0 will run with liquid dewars and vacuum pumping

– Goal - 2 K heat load for the cryostat is 50 watts– The vacuum pump planned for SPX0 has been measured at 64 watts at 23 torr (2.0 K)– If more pumping is needed there is an option to add additional pumping

Helium riser heat flux limit estimated by Gary Cheng– 98 watts at 2.0K, 59 watts at 2.07K

Thermal shield will use LN2 for SPX0– Will test at JLAB with ~50K helium

Heat load estimates do not include male bayonets and distribution system


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Cryomodule Heat LoadSPX0 Heat Load components 2 k Shield per per per per per perHeat loads per Item # Static Dynamic Total Total Static Dynamic Total Total

Cavity 2 7 14 0

HOM 4 1 1.3 2.3 9.2 0.37 0.72 1.09 4.36

LOM 2 1.36 0.21 1.57 3.14 12.05 0.35 12.4 24.8

FPC 2 1.14 0.48 1.62 3.24 5.09 0.45 5.54 11.08

Beam Tubes 2 0.14 0.16 0.3 0.6

Component Totals 9.28 20.90 30.18 35.8 4.5 40.24

Static Cryostat Estimate 12 12 144 144

Total 42.18 184.2


LOM

FPC

HOM

Beam pipe

Interfaces

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Director's CD-2 Review of the Advanced Photon Source Upgrade Project 11-13 September 2012

Cryogenic P&I D

Interfaces

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4 HOM dampers, 2 per cavity

Each HOM damper

(1) Water flows FI SPX 23

(1) Water temp ITQ SPX 23

(2) Heaters CHR SPX 23 & 23A

(2) T-couple (inside vacuum tank) ITQ SPX 23 A & B

Field probe outside of thermal shield RFP SPX 23

(2) diodes on vacuum waveguide CTD SPX 23A & 23B

Cavity P&I D

HOM as an example:

Cavity and Cryomodule Fault Analysis Summary (1) Accidental venting of beam line, insulating vacuum Cryogenic trip or power outage Helium circuit leak to insulating vacuum Helium circuit leak to beamline vacuum Cavity quench Window arcing Tuner failure Beam line valve failure Cavity performance degradation Excessive heating to 2K circuit Beam line mis-alignment greater than spec

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Cavity and Cryomodule Fault Analysis Summary (2) Cavity mis-alignment HOM load bonding failure HOM load SiC performance degradation HOM load water flow stops HOM load water leak in insulating vacuum space Excessive microphonics Field probe faults Cryogenic acoustic resonance

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Summary

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• SPX0 Design solutions have been developed• Cavity prototypes qualified• Prototypes of critical components are in progress

• Vertical alignment is critical• Low impedance bellows need beam test• LOM/HOM damping must be very strong

• Cryomodule design mostly completed, ready for procurement/fabrication


spx0 cavity and cryomodule systems wbs 01.02.01.03.05

Documents

beam diagnostics

beam feedback

2012spx0 review

spx0 cavity

vertical beam size

cavity alignment

cavities mark

cryomodule systemswbs