Existing Arcs and 4m DipolePreliminary Design and Safety Review

Beam Transport Interface

Mike Bevins

February 22, 2007

12GeV Upgrade - Beam Transport

• Existing C-style dipole interface• What’s NOT changing• New H-style dipole interface• Alignment plan• ARC shifts• ARC Vacuum• Safety• Cost Estimate & Schedule• Risk Assessment

Beam Transport Interface - Outline

Existing C-style dipole interface

ARC Dipoles

B-line – vertical bending dipole

Existing C-style dipole support

Beam Direction

Typical ARC and hall transport horizontal bending dipole support scheme

Outrigger bolted to magnet core

Alignment cartridge cap

Tie bar (fastens cap to magnet core)

Alignment cartridge base bolted to stand

Existing C-style dipole support

What’s NOT changing

• Alignment specs– Position to +/-0.5mm in x & y, +/- 1.0mm in z

• Vacuum specs– Beam line partial pressure of hydrogen <10-6 torr– Total pressure of all other constituents less than 5x10-7 torr– Fabrication, welding, cleaning & handling, and leak checking

specs still apply • 22631-S-001 Fabrication of Ultra-High Vacuum Equipment• 22632-S-001 Cleaning and Handling of U.H.V. Components• 22633-S-001 Welding Specification For U.H.V.

Components• 22634-S-001 Helium Leak Test For U.H.V. Components • Note an update and consolidation of our vacuum specs is

underway• Support stands• Dipole chambers

New H-style dipole interface

Prototype H-style dipole

INTERFERENCE

H-steel interferes with existing outrigger support

•H-steel runs directly through the holes tapped into the magnet core used to support the outrigger

•Prefer not to cut away H-steel to clear existing support

New H-style dipole interface

Proposed solution•Eliminate outrigger supports

•Build single cap that spans both cartridge bases

•Requires NO modification to magnet core

•Requires NO change to cartridge base support structure

•Does require 3rd flat on one of the cartridge basses for adjustments normal to the beamline

3rd flat req’d on this cartridge base

Bracket to fasten cap to magnet core

New H-style dipole interface

Increased cap thickness to support cartridge post (previously reinforced by outrigger)

Cartridge post

Fastener in existing tapped hole

Alignment Plan – Existing schemeExisting C-style dipole alignment scheme •Alignment fixture indexes on machined flats on each end of the magnet

•Two bolts are used to fasten the fixture to the magnet (mounting holes tapped into upper machined surface on the magnet core)

Problems -

•Lab alignment group reports that it can be difficult to ensure that the fixture is seated properly against the magnet

•Scheme only provides two alignment points on each magnet

•Fixtures would require modification to eliminate interference with new H-steel dipoles

Existing C-style ARC dipole

Existing C-style dipole up-beam alignment fixture dipolePrototype H-style dipole

Machined flats

Existing C-style ARC dipole

Alignment Plan – Existing scheme

Alignment Plan – New scheme

Use threaded retro-reflector nests in old fixture fastening holes

•Provides four points for alignment

•Alignment group has done mock-up to confirm line-of-sight with the addition of H-steel

•Additional testing is planed to check repeatability of the installation of nests and the location of the tapped holes in the magnet core

•May need to fiducialize each dipole and leave nests in place

C-style ARC dipole with retro-reflector nests installed

Retro-reflector nest

Alignment Plan – New scheme

Retro-reflector nest line-of-sight check with mock H-steel (viewed from laser tracker)

Mock H-steel

Alignment Plan – New scheme

Threaded retro-reflector nest

Alignment Plan

Vertical bending B-line dipoles

•Dipoles are aligned using four tooling ball nests mounted to side of dipole

•Addition of H-steel does not interfere with existing scheme

•NO CHANGE REQUIRED

Vertical bending B-line dipole

Z

X

0,0

East ArcWest Arc

ARC ShiftsTo accommodate changes in the spreaders & recombiners the beam path length must be adjusted by shifting several arcs•Shifts are pure z-shifts

•Current optics design calls for small shifts that are likely well within the remaining adjustment in the alignment cartridges (nominally +/-1cm)

•Remaining adjustment will be field checked later this year

•Preliminary designs have been developed to accommodate shifts ~1cm if required

WestARC

Z Shift[mm]

EastARC

Z Shift[mm]

2 -1.413 1 0.0104 -0.013 3 2.7686 -0.002 5 -0.0218 0.778 7 0.020

9 0.035

ARC Shift – Design for ~1cm shift

Goal : Shift arc dipoles and quad girders in machine z ~1cm without altering the support stand, dipole, or quad girder

•Dipole shift solution

Bracket slotted along the axis and normal to dipole

Tie bar & shim can be replaced with bracket slotted along the axis and normal to dipole

Up-beam dipole support Down-beam dipole support

ARC Shift – Design for ~1cm shiftQuad Girders

•Mounting very similar to dipoles

•Alignment cartridge caps fastened to girder with two bolts and pinned using button feature on the cap

Typical arc girder interface

Typical cartridge cap

Button

Threaded holes

ARC Shift – Design for ~1cm shift

Solution for quad girders

•Replace existing 4”x4” caps with a two piece 5”x5” design that incorporates the shift

•The inner disk eccentrically revolves the upper girder mounting features on the outer body around the fixed cartridge base

•Outer body of the cap can be used in every arc that requires a shift

•The inner disk would be arc shift specific

•Design would NOT limit the nominal range of adjustment

•Depending on the final magnitude of the shifts and the number of arcs requiring a shift it may be simpler and more cost effective to have multiple one piece offset cap designs

Cartridge base

Outer body

Inner disk

Shift

ARC Vacuum

The gas load will increase over the present 6GeV design as a result of:•Increased thermal outgassing

•Dipoles running hotter heating the chamber walls

•Synchrotron radiation heating near dipoles

•Increased photon stimulated desorption from synchrotron radiation

•Rough calculations indicate that initially local pressures will be higher than present condition

•Initial consultation with CASA indicates that this will be acceptable

•A more detailed vacuum study is underway and will be presented as part of the Preliminary Design and Safety Review of ARC 10 and Hall D layout in April of this year

•Ion pumps & valves are planned to be refurbished as part of the normal CEBAF maintenance

Safety Considerations

•Personnel training

•Jlab & sub-contractor

•Radiation

•Designated areas for containment and radiation survey of materials that will be removed from the tunnel

•Storage

•Vacuum drift tubes & bellows, hardware, misc. supports

•Material handling

•Hot work

•Electrical Hazards

Details to be presented as part of the Installation Plan and Estimate Review to be held in May of this year

Cost Estimate & Schedule

•Detail design to be completed late in FY08

•Fabrication and delivery to support installation activities in FY12

Existing parts getting replaced (cartridge bases, caps, etc…) will likely be used elsewhere in the machine!

DescriptionUnit CostEst. [$]

QtyReq'd

Program Cost [$k]

H-Style dipole dounts 88.8Double cap 175 240 42.0Double cap bracket 45 240 10.8Cartridge base with 3rd flat 150 240 36.0

Alignment 10.6Retro-reflector nests 133 80 10.6

Misc vacuum hardware 3.5Misc installation costs 5.0

Total Program Cost: 107.9

Procurement Cost FY07$

Cost from catalogCost based on recent PO

Engineering estimate

Alignment 127.7

Retro-reflector nests (if left on mag) 133 960 127.7ARC Shift (per arc) 18.2

Downbeam dipole cap bracket 75 32 2.4Two-piece cap on quad girders 160 99 15.8

Costs Outside of Current Scope

Risk Assessment

Technical - Low•Supports -similar designs exist and are already proven

•A prototype of the H-style dipole double cap is planed to check installation onto alignment posts

•Vacuum - rough calculations suggest no changes required•Detailed study underway

• Alignment - proof of concept complete

Procurement Schedule - Low•No long-lead items identified

Cost – Low•Significant portion of cost is based on engineering estimates

•Plan to refine with vendor quotes•Uncertainty in remaining adjustment in cartridges to accommodate arc shifts

•Plan to confirm with field check

Summary

• Plan and estimate to support/align modified dipoles complete

– Plans are in place to confirm present assumptions

– Alignment and installation personnel involved in designs

• Risks are low

• Safety considerations are similar to existing ones sans scale

• Detailed vacuum calculations are underway – preliminary studies indicate no change required

Conclusion and Reminder of ChargeThanks to the review panel and all participants!

George Biallas (Chair), CASA Representative, Bob May, Chris Curtis

• We appreciate comments for the reviewers and all in attendance• Preliminary design reviews shall address the readiness of the design to be

taken to final/detailed design

– Technical

– Safety

– Cost

– Risk

• The preliminary design review should generate a list of follow-on items to help the designers/engineers in their jobs

– What needs to be addressed or considered prior to the CD2 Reviews?

– What needs to be addressed or considered during the detail design next fall?

• Questions?