Report from HIE-ISOLDE HEBT WG J.Bauche‎, P.Farantatos‎, M.Fraser‎, B.Goddard, Y.Kadi‎, D.Lanaia‎, D.Nisbet‎, E.Siesling‎, G.Vandoni‎, D.Voulot‎, E.Zografos Outline Working group composition and objectives Technical progress Present status and outstanding issues Timelines for progress and decisions Conclusion

Working group composition J.Bauche, TE/MSC: Magnets P.Farantatos, TE/MSC: Magnets M.Fraser, BE/RF: Transverse and longitudinal optics B.Goddard, TE/ABT: Coordination, transverse optics Y.Kadi, EN/HDO: HIE-ISOLDE project leader D.Lanaia, BE/OP: Commissioning D.Nisbet, TE/EPC: Powering D.Siesling, BE/OP: Layout and infrastructure G.Vandoni, TE/VSC: Vacuum D.Voulot, BE/OP: Coordination, commissioning E.Zografos, EN/MEF: Integration, layout

WG documents and minutes EN dept EDMS node Proj. Id: CERN v.0

Working group objectives Finalise transfer lines optics for each stage Parameters for magnets and power supplies Beam instrumentation requirements Vacuum and sectorisation Update layout and check integration Define powering scheme for line elements Validate trajectory correction strategy Launch specifications for equipment production

HIE-linac installation Present 11/2014 4/2016 3/ MeV/u 5.5 MeV/u 10 MeV/u

3 experimental stations (2 installed in stage1) TSR line and optional ‘car park’ line Modular lattice 8 lines: XL (REX Linac), XT00 – XT06 (REX Transfer)

Possible TSR layout (see Fred’s talk)

Naming convention Follow existing REX/ISOLDE conventions for slot names Keep names compact and simple Try to meet layout database requirements

Beam Optics Periodic focusing channel 3.2 m period Long drift for benders Short drift for beam diagnostics/correctors Matching section

Optics and layout Decided to keep one 90  and one 45  bend beamline (XT01 and XT02) Reduced from 2 to 1 quadrupole designs, 200 mm magnetic length Decided maximum quadrupole strength of 25 T/m and inscribed diameter of 50 mm, with 40 mm vacuum chamber ID SC linac to periodic channel matching section: 2 standard quadrupoles Investigating single quadrupole in achromat module, rather than split (2) quadrupoles Investigating increasing main dipole bending field from 1.0 to 1.1 T -> more compact magnets Optimizing layout and element spacing as a function of magnet design estimates – physical magnet envelopes critical -> exact beamline position not final

Magnet design, parameters and powering Decided that magnets do not need to be ‘fast’ switching – so laminated cores are not essential (but maybe cheaper for series production) – DC power supplies Decided to reuse GSI 22.5  SBEND dipoles for XT01, with new 45  SBEND dipoles for XT02 (investigating spares and documentation) Magnet powering expected to be with off-the-shelf convertors – first magnet design still needed for detailed characteristics Decided to have diagnositic box and steerer in each period. Steerer strength 6 mT.m to be checked with error study. Number of separate powering families still to be define Error/steering study: to make (new Fellow 1 st March)

Linac shielding Current tunnel: – RP request 40 cm concrete or 10 mm lead – Existing shielding 40/80 cm concrete, 2*10 mm lead plates for end wall Need radiation study for SC linac Baseline: tunnel 80 cm concrete/end wall lead (20 mm?) Reserve 85 mm space in the lattice for the end wall The full tunnel is installed in stage1 Access door on Jura side

Stage 2b Matching section: issues Shielding (end of tunnel) Coldtrap region

Beam instrumentation One diagnostic box per period (at least keep space) Use SC-linac ‘short box’ – Faraday cup – H-V slit profiler Modular boxes: possibility to add special tools (Si-det, collimators, stripping foils) Emittancemeter at the end of the XT00 line AVS company – Gipuzkoa, Spain

Vacuum system HEBT Baseline is pumping via Diagnostic Boxes only – needs mechanical design and calculations Sectorisation defined with each separate line, sector valve behind first bender at the start of each line and in front of experimental station Coldtrap needed between end linac and start XT00 – 400 mm available in layout which should be sufficient (need to reserve space for a cold trap in front of SC-linac too!) Exact valve positions/envelope: need magnet design for integration Stripper foil in DB between the two benders, one for each line

Access to experimental area Counting room outside controlled area foreseen (new building) Prompt radiation due to high energy beam (neutrons) unlikely to be an issue but – Need supervision: BLM, radiation monitors – Need to monitor beam intensity (stable beam) Activity from radioactive beams: situation is unchanged -> ongoing discussion with RP

HELIOS magnetic shielding Assume 5 mm displacement (R_ap/4) in one period (3.2m), A/q = 2.5 Similar for ISOLDE beams (30 kV, A=10, q=1+ -> 1 G) Not compatible with blind scaling for radioactive beams

HEBT Timeline Conceptual design review: 25 April 2012 – Agree on concept and optics solution found Technical design review: early July 2012 – Agree on technical design solutions Finish of technical specifications: end Nov 2012 – Magnets, powering, vacuum, instrumentation Launch of tenders: end February 2013 – No finance committee contracts End of manufacturing: end July 2014 – 17 months from tender launch – OK if no other delays Start installation: August 2014 – 2 months foreseen: beware parallel Linac commissioning Start beam commissioning: October 2014 – First commissioning, system checks and performance validations Physics operation: start 2015

Main remaining issues Choice of split or single quad for achromat Acceptable strength of main dipoles “Final” iteration on layout and optics with realistic magnet envelopes, once these two things are known -> line position can still change a bit Error and steering study to validate aperture choice and steerer strengths Layout and integration validation with all beamline elements

Conclusions General layout and main options are fixed Need to finalise optics and define specifications Tight schedule but feasible – need careful planning of installation and commissioning

Technical progress and status – Present HEBT layout and parameters – Layout, footprints, shielding and integration – Naming conventions and documentation – Optics – Magnet design, parameters and powering – Instrumentation – Vacuum system

HEBT layout and parameters

Present HEBT installation

5.5 MeV/u: November 2014 HEBT installation

10 MeV/u: April 2016 HEBT installation

Low beta section and chopper line: April 2017 HEBT installation

TSR and optional beamline: not yet decided HEBT installation