Report from HEBT Working Grouphttps://edms.cern.ch/nav/P:CERN-0000072786:V0

B.Goddard, CERN TE/ABT

On behalf of Erwin Siesling; Matthew Alexander Fraser; Didier Voulot; Davide Lanaia; Yacine Kadi; Jeremie Bauche; Panagiotis Farantatos; Giovanna Vandoni; Eleftherios Zografos; Angelina Parfenova; Michele Martino; William Andreazza;

Richard Mompo; Antti Juhani Kolehmainen; Marc Timmins

Contents

• HEBT technical design review outcome• Latest version and (relevant) features of HEBT design• Evaluation of low-energy performance• Status of HEBT subsystems

– Diagnostics– Magnets– Power convertors– Vacuum– Interlocking– Supports and alignment

• Remaining issues and concerns• Conclusions and outlook

HEBT technical design review• Held on 6th July 2012

• Follow-up of the Conceptual Design Review held (already way back!) on 25th May 2012

• Reviewed the technical designs and system specifications to allow Market Surveys and Invitations to Tender be launched in time (from Autumn 2012).

• To validate or point out weaknesses

Review organisation• 09:00 - 09:15 Introduction, schedule and objectives (10+5') 15‘, B.Goddard• 09:15 - 09:40 Diagnostic Boxes: detailed design (20+5’) 25‘, J.-J.Gras• 09:40 - 10:05 Magnets: ST, MQ and MD magnetic design (20+5’) 25‘ J.Bauche• 10:05 - 10:30 Power convertors: technical choices and designs (20+5’) 25‘ M.Martino• 10:30 - 10:45 Coffee break• 10:45 - 11:00 HIE-ISOLDE HEBT vacuum system (10+5’) 15’ M.Hermann• 11:00 - 11:20 Interlocking: system architecture and design (15+5’) 20‘ R.Mompo• 11:20 - 11:40 Supports and alignment/survey (15+5’) 20‘ M.Timmins• 11:40 - 11:55 Integration: model and known issues (10+5’) 15‘ E.Zografos• 11:55 - 12:10 Experimental zone access, beamline controls and SW (10+5’) 15‘ D.Voulot• 12:10 - 12:25 Optics: expected performance for 0.3 MeV/u (10+5’) 15‘ A.Parfenova• 12:25 - 14:00 Lunch• 14:00 - 14:30 Reserve 30'• 14:30 - 16:15 Closed review session• 16:15 - 16:30 Coffee break 15'• 16:30 - 17:30 Open review session and summary

Reviewers

• Review panel– Wolfgang Bartmann, TE/ABT– Lau Gatignon (chair), EN/MEF– Thomas Zickler, TE/MSC– Roberto Kersevan, TE/VSC– Alessandro Dallocchio, EN/MME – Uli Raich, BE/BI– David Nisbet, TE/EPC

https://indico.cern.ch/conferenceDisplay.py?confId=194310

Reviewers’ conclusions I• Instrumentation is on critical path. It could be a potential

showstopper for a start-up in 2014.• Recommend strongly to order all magnets of the same type in a

single contract.• The separation between linac and transfer line reviews is in certain

aspects artificial.• Address planning and resource issues to guarantee a timely design

and procurement strategy for the beam instrumentation and its associated electronics.

• Study the choice of steel type in terms of mechanical and magnetic behaviour for vacuum tubes and diagnostic boxes.

• Measure field quality of existing 22.5 deg bends at low fields to ensure adequate performance.

Reviewers’ conclusions II

• Check magnetic and mechanical interference of correctors on neighboring equipment, in particular vacuum components and instrumentation.

• Verify that EM influence of power converters complies to tolerances to be specified by the neighboring experiments.

• Complete simulations of the effectiveness of cold traps and acoustic delay lines with respect to latency of fast valves.

• Address all integration issues in detail, including services.• Evaluate RP aspects in case of significant increase of primary

proton beam intensities.• Include magnet non-linearities in optics simulations.

Reviewers’ conclusions III

Latest HEBT design• All details on EDMS (HIE-ISOLDE/HEBT LINES OPTICS AND LAYOUT)

– Drawings, layout tables and (new) madx reference optics files

Relevant features

• All beamline elements fully integrated– Some changes to layout to make this possible – included in

latest optics versions

• Integration following element design– Now addressing services, cable connections etc.

• Reduced drift to experimental station #3 in XT04– Remove one double period (fewer magnets, save some $$)– Now identical achromat and final focus to XT01

• Diagnostic box contents all defined– 4 variants, included in updated specification

Stage 2b

Evaluation of low-energy performance

• Recall that baseline HEBT design is 3-10 MeV/u• Optics evaluated with 0.3 MeV/u

– Increased error contributions from remnant fields, powering ripple, powering accuracy

• Results shown for XT01

X-plane: beam sizes, maximum particle deviation, aperture

STATIC: All Error-Sources

Before/after correction

XT01 Trajectories X / Y, 100 seeds

XT01 DYNAMIC errors: dipole and quadrupole power ripple

X distribution at the target

(instability due to power ripple)

≈ 0.5 mm

500 seeds

“Full (95%) beam sizes” = “spots” at XT01 target

500 seeds

Required 3-4 mm beam spot X/Y. Factor 2 larger in both planes

Remaining acceptance

N(x/y) = [ APER(x/y) – X/Y(corr.+dynam.) ] / sqrt [ e_(x/y)*beta_(x/y) ]

Conclusions for 0.3 MeV/u

• Remaining aperture was estimated at about 2.5 for X and about 3.0 for XT01

• Transmission is expected to be good (above 95%• Stability at target is expected to be about 0.5 mm in

X (1 sigma)• Beam size at target is about 6-7 mm (95%)

– May need collimation if this is too big. Experiments…?• Still to estimate beam transmission using PTC track

for both XT01 and XT02 • Looks feasible for this mode of operation

Subsystems - diagnostics

• DB functional and mechanical specification finished• Design fulfills requirements and is approved• Market Survey document in preparation• Prototype Faraday cup being tested at CERN• Prototype DB being assembled at AVS – expected at CERN

early October for tests• Cabling needs defined and requests made • Concern about electronics (acquisition and positioning)

progress – working with BE/BI to define strategy• Worries about alignment accuracy in Linac between SC

modules – being investigated

Diagnostic boxTYPE IV

Collimator slitType 2

FC

Scanning slitSilicon

detector

Stripping foils

Subsystems - magnets• Requirements, specifications purchasing strategy fully defined• Magnetic measurements all to be done at CERN• 22.5 deg dipoles: Coil orientation reversed. Refurbishment ongoing, electrical

and magnetic measurements to do. Missing specification details for spare coils.

• 45 deg dipoles: Electrical, cooling and vacuum interfaces defined, magnetic design done, mechanical design and technical specifications ongoing, tendering end Oct. 12

• Quadrupoles: Electrical and cooling interfaces done, vacuum and survey ongoing, magnetic design ongoing (steel selection critical), mechanical design and technical specification ongoing, tendering Nov. 12

• Steerers: Design updated after CdR (water cooling), electrical, cooling and vacuum interfaces defined, magnetic design done, mechanical design being adapted to watercooled version, technical specifications started, tendering end Oct. 12

Magnets

Subsystems – power convertors• All requirements finalised and technical solutions being defined• FGC3s to be used for all control• Quadrupole:

– Industry. Current reversal needed for 4 units. Foreseen solution validated in tests and a draft specification is almost ready. The current looping control needs some more work.

• Steerer: – CERN design and assembly. MS deadline is set for October and tendering in

December 2012. The first batch is then expected at CERN in December 2013. Second batch in 2015.

• Dipole: – CERN S250 design. Power converters to start production in 2014.

• SC solenoid: – LHC 600A/40V 4 Quadrants (LHC spare for Stage 1)

• Issues with power convertor rack placement….

Power convertors

Subsystems – supports and alignment

• Requirements fully defined• Technical solutions defined• No technical issue to meet required tolerance• Detailed design in progress• Cost estimates to refine• Tendering planned for end October

Supports and alignment

Subsystems - vacuum

• Requirements fully defined and specifications documented• Technical solutions defined

– Sectorization in 4 vacuum sectors– Diagnostics by cold cathode gauges of pirani type and passive

penning gauges on T-pieces– Turbo pumps (60 l/s) on diagnostic Boxes: ~1 every 2 DB– Protection of SC linac vacuum by fast valve + cryotrap (still needs

calculations on effectiveness)• Vacuum chamber and bellows detailed design in progress.

– Vacuum system design ‘closed’ for HEBT– Issue with bellows and DB alignment in the inter-cryomodule

region. SC module tolerances being discussed.• Procurement fully in-house

Vacuum

courtesy J.Bauche

GSI magnets, Al chamber

PRE-STUDY

DIPOLES QUADRUPOLES

Subsystems - interlocking

• Requirements defined • All documentation updated in detailed WP definition. • Technical solution defined

– Thermoswitches on all magnets, and some flow switches for dipoles.

– PLC based as for other CERN WIC systems– Integration of switches on magnets/supports

• Cabling requirements defined and requests made• Potential issue with the SC solenoids where the

protection needs defining.

Interlocking

Configuration DB

Software “Beam Permit” ?

ThermoswitchELMWOOD Type 3106 – T117

Remaining issues/concerns

• Electronics for diagnostic boxes (acquisition and positioning). Resources and priorities.

• Tolerances for diagnostic boxes in inter-cryo module region – SC module flanges

• Cryotrap effectiveness for protection of SC cavities• Budget constraints for procurement – need to be able to

source all components in single order, for all phases…– Nota bene: we are assuming that we will NOT have the configuration

with 5.5 MeV/u beams (2 SC modules) plus the UBEND beamline…

• Schedule still tight for end 2014 commissioning

Conclusion• Positive outcome of Technical Design Review in July• Good technical progress with designs of all systems• Now well into the technical specification and tendering

preparation phase• No major schedule delays identified (yet) – should still be on

track for commissioning end 2014• Some remaining concerns being addressed; no showstoppers

identified (yet)• Operation at 0.3 MeV/u looks feasible with the present

equipment specifications and design• Some re-focussing of the HEBT WG scope being discussed, to

cover also beam dynamics through Linac. Not yet in place.