capture cavity 1 readiness review elvin harms, yuriy orlov, tom peterson 5 september 2012

Capture Cavity 1Readiness Review

Elvin Harms, Yuriy Orlov, Tom Peterson5 September 2012

CC1 Readiness Review 5 September 2012

0900: Introduction/Effort since May Review/Review of Recommendations – Elvin Harms

0915: Design Considerations – Tom Peterson

0925: Design & Drawings Overview – Yuriy Orlov

1015: Finite Element Analysis – Nandhini Dhanaraj

1045: Assembly Scheme – Evgueni Borissov

1115: Additional Q&A – All

1145: Discussion and preliminary conclusions – Committee

1200: Closeout – All

a final written report would be appreciated at a later date (ideally within 1 week of review)

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Agenda


• Thank You for your participation today• "Capture Cavity 1" (CC-1), is a single-cavity cryostat containing

one 1.3 GHz 9-cell cavity.• CC-1 operated at A0 for many years and will be installed later this

year in NML as part of the new Advanced Superconducting Test Accelerator (ASTA) with an updated cavity capable of higher gradient performance (>25MV/m compared to 14 MV/m previously).

• The old RF cavity will be replaced with a new one that physically differs in several ways:

• blade tuner rather than end lever tuner (which means a new helium vessel of a different style and different helium piping)

• reconfigured piping geometry, and a few other modifications• The new design incorporates lessons learned and suggestions

made based upon operational experience and the modern design of other single cavity vessels including HTS here at Fermilab.

Introduction


• Please objectively review and comment on the overall design as well as specifically address the following:

Have the recommendations made at the previous review been addressed satisfactorily?

Is the assembly scheme satisfactory? Are drawings, simulations, plans, etc. sufficient to

proceed with procurement, fabrication, and assembly?

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Charge


Functional Requirements

The refurbished cryomodule must interface seamlessly to the existing cryogenics and vacuum systems in NML as well as be compatible with SRF components already installed in ASTA. For uniformity sake – ease of installation and repair, the input coupler, thermometry and other instrumentation/diagnostic signals should be identical to that found in the other SRF devices to the extent possible. In light of advances in design since CC1 was fabricated, modern cryomodule design techniques and sub-assemblies will be pursued while reusing as many of the existing parts as possible.


Technical Requirements - 1

• Particle-free UHV systems are required to maintain cleanliness and cavity and input coupler volumes at pressures on the order of 10-9 Torr.

• Cryostat must be modified in order to be able to house a 1.3 GHz 9-cell cavity outfitted with a blade tuner

• In lieu of a 5K thermal shield, provisions will be made for thermal intercepts at 5K.

• Indirectly cooled components including High Order Mode couplers, tuner motor, and ends beam pipe assemblies shall be thermally anchored to the appropriate cryogenic circuit so as to provide adequate cooling.

• An adequate support structure, integrated to the existing superstructure, will be designed and fabricated capable of providing the necessary stability for the cavity during transportation and normal operation


Technical Requirements - 2

• Cryogenic piping will be positioned and fitted with connections to allow easy interface to the ‘top hat’

• Cernox© resistors will be the thermometry of choice.• 80K shield will be modified to allow for relatively easy access to

the cavity vacuum isolation valves at each end of the module without compromising the function of the shield

• Tuner motor will be of a style to provide reliable operation in cryogenic, UHV, and radiation environment.

• Vacuum vessel flanging will be modified as needed to accept the input coupler attached to the new cavity and accept all instrumentation feeds.

• All internal components will be supported so as to minimize motion and damp vibration which could adversely affect cavity performance.

• Alignment checks and fiducials will be provided so as to ensure alignment of the cavity center on the beam line to within 200 microns.


Safety Requirements

• Cavity and cryostat must comply with the applicable SRF Cavity and Vacuum Vessel Standards set forth in the FESHM chapters

• All systems shall be equipped with appropriate relief valves per applicable FESHM chapters to protect against over-pressurization

• All piping must comply with the ASME/ANSI B31.3 Process Piping design code.


Quality Assurance Requirements

• Careful documentation of the disassembly and refurbishment of the CC1 cryomodule, both written and photographic should be kept. This allows for ease in troubleshooting should problems arise during operation.

• A complete set of ‘as found’ drawings will be prepared once the work is finished.

• To the extent possible, the tuner, instrumentation, and electrical connections will be tested and confirmed operational prior to closing up the vacuum vessel.


Effort Since May Review

• Design work continues, especially• Ends• Gate valve support• Thermal intercepts• Piping

• Remove option to make port for tuner access through vacuum vessel

• FEA (Nandhini)….• Assembly tooling and scheme (Evgueni)• Design/Drafting effort ramped up• Schedule/Effort/Cost estimates developed• Long lead time items procurement initiated


Recommendations from May Review

• Develop assembly sequence for the end beam tube spools considering cleaning, leak checking, bellows temporary vacuum support and final end cap installation – discussed, needs to be written down

• Investigate cumulative tolerance effect on cavity alignment and needle bearing slide performance – discussed, see Yuriy’s slides

• Investigate pin anchor tolerance and flexing on cavity alignment – analysis complete

• Investigate alternative cavity and vacuum valve slide scheme in order to minimize the number of bearing surfaces and therefore the potential for binding – updated, see Yuriy’s slides

• Add the port to the vacuum vessel and 80K shield to allow access to the slow tuner after understanding the implications on the 80K shield trace tube routing – removed


Recommendations from May Review - 2

• Analyze the total force on the support rods after considering the increased total weight of the cold mass, pre-stress requirements and cool down stress – complete, see Nandhini’s slides

• Analyze cool down stress and distortion where dissimilar metals are connected or thermal resistance exists – complete, see Nandhini’s slides

• Investigate the thermal effectiveness of the various clamped thermal intercept strap schemes and consider ways to minimize the reliance on small mechanical contact resistance methods – complete, see Tom’s slides

• Develop a preliminary cryomodule assembly scheme in order to ensure that access to components, such as intercept straps or cabling, is convenient – discussed, see Yuriy and Evgueni’s slides


Recommendations from May Review - 3

• Consider if there are practical means for reducing the number of flanged 2K joints within the cryostat – completed

• With the removal of the 5K shield, the functionality of the 80K shield becomes more important. Carefully consider openings in the shield where 2K surfaces could see room temperature surfaces – integrated into design

• Add MLI to the helium vessel and two-phase pipe in order to limit the heat load during loss of cryostat vacuum accident – will be done

• Evaluate the additional heat load to 2K, both generally and locally at attachment points – see Nandhini’s slides


Next

• Tom – Design Considerations (10 minutes)• Yuriy – Design Overview (50 minutes)• Nandhini – Structural and Thermal Analysis (30

minutes) • Evgueni – Assembly (30 minutes)


Backup Slides


Schedule/Effort Estimate

• Alignment - 2 days/1 crew• Instrumentation - 1 week/2 people• Clean room Assembly - 1 week/2 people• MP9 Assembly – 3 weeks/3 people• Checkout – 1 week/2 people

• Arkan – 10%• Borissov – 10%• Harms – 10%• Orlov – 40%• Peterson – 10%• Premo – 50%


M&S Estimate

ItemEstimated cost/unit # units Total Cost comments

Magnetic Shielding $0.00 in handGate valve 2 $0.00 in handBlade Tuner 1 $0.00 in handBearing Supports $1,000.00 4 $4,000.00Needle Bearings 4 $0.00 in hand

Frame $2,000.00 1 $2,000.00fabricated outside?

Piping $3,000.00 1 $3,000.00

Thermal Intercept Braids $1,000.00 1 $1,000.00 in-house

End Cap shields $0.00 re-use existing?

Liquid Level Probe $0.00 re-use existing?

Cryogenic flexible hoses $500.00 6 $3,000.00

Main Input Coupler - cold end $0.00 in hand

Main Input Coupler - warm end $0.00 in handCoupler support $0.00 in handTotal Estimated M&S $13,000.00


Introduction to CC1 Upgrade

Tom Peterson5 September 2012


Old CC1

• Had a “Type 2” cryomodule cross section 2-phase pipe directly above the cavity End lever tuner No piezo (fine or fast) tuner mechanism

• Had a Saclay-style support structure Tension rods, axial pin

• Had a makeshift 5 K thermal shield • Gate valves were oriented vertically


New CC1 differences

• Dressed cavity identical to a CM2 dressed cavity • 2-phase pipe position off-center (“type 3” helium

vessel) Rework CC1 helium piping to match

• No 5 K shield, but 5 K thermal intercepts • Gate valves accessible and better supported • Blade tuner rather than end lever tuner

Tuner and motor in new location Support structure has to accommodate slight helium vessel

motion Adapt support connections to present helium vessel structure

with bearing supports Option: Add an access port to tuner drive through vacuum

vessel and 80 K shield? -- No, decided against this additional port


Other Features for New CC1

• New input coupler (modern TTF-type) • Incorporate lessons learned from other single-cavity

cryostats including old CC1 End bellows better supported to prevent vibration, including

thermal intercepts Aluminum frame structure with effective thermal intercepts

• Blade tuner improvements included Latest improvements with drilled motor shaft, loctite

• Thermal intercept improvement with flat surfaces and grease (references provided by Rich Schmitt -- several publications by Salerno, Kittel, et. al., in “Cryogenics” and “Advances”, 1992-4)


Remaining work

• We estimate a total of about 90 - 100 drawings including assembly and installation

Drafting team is on them now, completion in a few weeks Checking and any required revisions a few more weeks

• Procurement packages complete early October • ~ 1 month requisition, 2 months fabrication for end

groups, piping, support frame, etc. • Parts at Fermilab end of year • Assembly including clean room work, ~ 6 weeks • Completion end of Feb 2013


Other documentation

• Engineering documents Drawings -- intense effort from drafting over the past few

weeks -- ~67 drawings done (need checking) 70+ other drawings exist already for cryomodule work P&ID Piping engineering note Vacuum vessel documentation Updates for NML system, FMEA, etc.

• Preliminary operational readiness approval, vacuum pump down, warm operation (~ February, 2013)

• NML cryo safety review for cold operation (~ March, 2013)