Ghislain Roy presenting work of C. Carli, A. Garonna, D. Abler D. Kuchler, V. Toivanen, S. Myers, M. Dosanjh, and many others OPENMED - BioLEIR

The New CERN Initiatives 1. Medical Accelerator Design Coordinate an international collaboration to design a new compact, cost- effective accelerator facility, using the most advanced technologies 2. Biomedical Facility Creation of a facility at CERN that provides particle beams of different types and energies to external users for radiobiology and detector development Iterative experimental verification of simulation results 3. Detectors for beam control and medical imaging 4. Diagnostics and Dosimetry for control of radiation 5. Radio-Isotopes (imaging and possibly treatment) 6. Large Scale Computing (simulations, treatment planning telemedicine etc) 7. Applications other than cancer therapy Will be carried out in a global collaboration

OPENMED A Biomedical facility at CERN, to provide particle beams of different types and energies to external users for radiobiology and detector development, and to allow iterative experimental verification of simulation results.

Introduction - Motivation Need for radiobiological research with ion beams:  Protons and Carbon ions in clinical use Improved dose distribution, but limited understanding of all effects Other ions than p and C could be better suited (for certain cases)  Incoherent sets of data (radiobiological and clinical) observed under different conditions  New dosimetry and imaging modalities to be developed for full potential of ion beam therapy  Radiobiology: cell survival for different ions/LET/doses, bystander effects, RBE …  Detector Development: in-beam prompt gamma/PET imaging, radiography, …  Physics: fragmentation, … Lack of Beam-Time for ions with an energy of more than 50 MeV/n:  Nuclear physics laboratories (e.g. GANIL, GSI, INFN LNS, ITEP, JINR …) Limited beam time available  Ion Beam Therapy Centers (HIT, CNAO, MedAustron) Limited range of ions Priority given to clinical use (treatments, dosimetry, quality assurance …)

CERN accelerators

LEIR Part of the SPS and LHC injector chain, Gets heavy ion beams (Pb 54+ ) from Linac3, Accumulates and accelerates heavy ions, Delivers heavy ions to the Proton Synchrotron. Heavy Ion program at LHC and SPS is very important at CERN, but is not active all the time; only a few weeks per year, not counting future proposals but OPENMED could use the rest of the time! No other machine required … minimum impact on other CERN programs Energy reach of LEIR appropriate for radiobiology experiments Fully stripped 12 C or 16 O up to 240 MeV/n with present main power supply And up to 430 MeV/n (magnet limit) with a new main power supply Limitations from radiation protection ? (higher energy with higher Z/A for light ions) Success of initial brainstorming meeting organised by M.Dosanjh demonstrates interest and usefulness of facility

LEIR and Linacs Linac 3 Linac 2 Linac 4 LEIR South Hall

LEIR Circumference ~78 m => energy reach suitable for studies of interest for hadrontherapy Transfer tunnel Proposed new extraction and extraction line

Introduction – Present LEIR Machine Layout E-Cooling Ejection D≠10m D≠0 D=0 Ejection kicker Quadrupole doublet dipole RF D=0 Injection Quadrupole triplet LEIR layout – ~two fold symmetry -> Opposite sections have identical properties Quadrupole triplets in cooling section -> lattice o.k. for cooling & injection Main hardware installed : Section 10 : Injection (D ~10 m !) Section 20: Electron cooling (D ~0 m) Section 30 : Ejection kicker Section 40 (D ~ 0 m) :  RF (small “Finemet” cavities, allows to install RF in extraction section)  Extraction septum (small dispersion -> small beamsize) Beam diagnostics, damper, bumper, … installed wherever possible

OPENMED modifications Transfer lines - from Linac3 - towards the PS Injection line Ejection line for PS transfer New ejection channel LEIR shielding wall New transfer line to experiment PS shielding wall Source (H O), Linac front end, Linac, Transfer line, Slow Extraction, Beamlines, Experimental area, Dump, Shielding, Ancillaries…

Linac3

Ion source Need separate source for light ions and heavy ions Choice of source independent of injector option ECR ion source would probably deliver the highest particle currents, with lots of operational experience in different existing facilities, and being commercially available. EBIS could be interesting if fast changes of particle types are requested. Supernanogan by Pantechnik

Light ion front end To avoid interference with the heavy ion physics program a new light ion front end is also needed Four options have been studied 1. Linac3 extension 2. High Energy RFQ 3. New Linac 4. Cyclotron With limited resources we could follow up with only one of these options

Linac3 extension AdvantagesDisadvantages Most advanced study Reuse of Linac3 hardware No new location required Cheapest option Least time to realize Linac3 modification required (switchyard) Existing IH-DTL limitations Linac3 hall space limitations Linac3 radiation safety revision Installation limited by Linac3 operation No light and heavy ions in parallel Starting from existing hardware … SpeciesCNONe Intensity

High energy RFQ AdvantagesDisadvantages No limitations from existing hardware Location not tied to Linac3 Light and heavy ions in parallel Simplified design with only one accelerating structure Long and expensive RFQ Impractical accelerator for high energies All new hardware required New location required As a new RFQ is needed anyway …

New linear accelerator (Linac5) AdvantagesDisadvantages No limitations from existing hardware Location not tied to Linac3 Light and heavy ions in parallel Higher final energy possible Proven concept (existing facilities) Suitable designs available All new hardware required New location required Extend the anyway needed RFQ “only” by some cavities …

Cyclotron AdvantagesDisadvantages No limitations from existing hardware Location not tied to Linac3 Light and heavy ions in parallel Higher final energy possible Compact design Increases cyclotron experience at CERN All new hardware required New location required Less ion species flexibility Low beam intensities Capabilities of commercial devices need to be verified for all required ions Cyclotron related technology currently not common at CERN Let’s try something completely different …

Front end choice Decision: new linac option Start technical design of a “Linac5” and related beam dynamics studies Integration with other CERN studies/projects Beam parameters must be determined based on user request And remember that operation with light ions can trigger serious radiation issues

Transfer Lines and LEIR Do not jeopardize the heavy ion program No change to Linac-LEIR transfer line No major change to LEIR machine Except: New power supplies for some elements  main bends operationally limited to 4.8 Tm, i.e. C 250 Mev/u; design limit is 6.7 Tm i.e. 440 MeV/u  some power supplies in transfer lines might limit the ability to quickly change from light to heavy ions New slow extraction system

Slow extraction Detailed studies taking 12 C 6+ reference ion at energies 430 Mev/u and 20 MeV/u Additional septa must not reduce acceptance for heavy ion accumulation Determines position of septa: ≈ -45 mm for electrostatic septum and ≈ -55 mm for magnetic septum Local orbit bump required around septa (otherwise most ions lost at other places as e.g. the magnetic septum for the fast ejection towards PS) Quad driven extraction + Easy to implement - Intensity Fluctuations - Varying beam parameters during spill Easier to Implement RF k nock-out extraction + Smooth spill with fast on/off + Constant beam parameters during spill - New hardware to be installed Better beam quality

Slow extraction Slow extraction based on 3 rd integer resonance  Shift of tune to bring particles into resonance  Transverse excitation (RF knock-out) Established method using existing or recuperated hardware, few new hardware

ES Slow Extraction Sextupoles to  Adjust chromaticities and  Excite 3 rd order resonance for extraction  Hardt condition Align separatrices used for extraction for different momenta Aperture and loss optimisations Sextupole settings at high energy challenging  Solutions compatible with magnet limits for both lattices found if one accepts high chromaticities LEIR: Q’ = 9 in horizontal plane for Hardt condition LEAR: Q’ = -8 in vertical due to limited sextupolar strengths  Use of sextupole magnets and bending magnet pole face windings (PFWs) Phase space plot at the position of the electrostatic septum for LEIR lattice Two particles with different momenta

ES MS SeptaElectrostaticMagnetic Physical Length86 cm120 cm Effective Length66 cm100 cm Septum Thickness0.1 mm10 mm Field Strength7 MV/m0.5 T Kick (400 MeV/u C 6+ )3.4 mrad80 mrad - Critical point is ES: very limited space + field strength limited by vacuum requirements for Pb operation Extracted beam Extraction geometry and Septa Extracted beam passes through modified kicker tank

Beam Lines 440 MeV/u 70 Mev/u Pencil Beam : 5-10mm FWHM Broad Beam : 50 x 50 mm 2 Field uniformity of better than 90% by cutting out large fraction of beam outside Gaussian core, but radiation protection and beam stability to be studied. 4 bends 12 quadrupoles Octupoles ? Wobbling or scanning devices ?

Potential RP Issues LEIR  First calculations only (S.Damjanovic)  Expect high radiation levels … roof shielding?  Should be refined with updated information (particle fluxes, vacuum chambers and magnets, additional lines ….)  New access point for operation with lighter ions ?  Beam stopper moved into EE line must be compatible with lighter ions in LEIR “Linac5”  Neutron production with 4.2 MeV/u light ions?  May have serious impact on the safety aspects of Linac Beamlines: vertical line going up ? Specific shielding ? Ambient dose rates around LEIR loosing O ions per seconds at E k =250 MeV/n Ambient Dose-Eq Rate [μSv/h]

Experimental Area Target station and biolab to be defined and constructed Patient treatment and live animal studies are excluded Live cells and other samples must be accommodated Sample preparation and handling requirements ?  Operational issues linked to lifecycle of samples ?  Regulatory issues ? Imagery and diagnostics ? Beam quality on delivery  Beam homogeneity over large areas (octupoles or other strategies)  Beam scanning and rastering (hardware and controls) Request for full energy at the vertical beamline

Beam Instrum. and Controls Control of extracted beam  Position: limit unwanted wobbling  Intensity: ions/s, or dose equivalent ? Instrumentation for very low fluxes and/or very diluted beams… Link with biolab instrumentation :  Imagery  Dosimetry: feedback on dose delivered ? Specific controls issues ?

Status and conclusions Demand exists for radiobiological research with ion beams  For studies required for a better understanding of phenomena relevant for hadron therapy  Which are not satisfied by existing installations (physics labs and hadron therapy centers) Proposal: upgrade of the Low Energy Ion Ring LEIR (moderate effort) ECR source and “Linac 5” front end selected  Detailed studies have started, and will include integration studies  Requires clear users’ requirements LEIR modifications fairly clear and within reach  Slow extraction; needs some HW design, use of spares and integration  Upgrade of main bends + transfer line power supplies Radiation protection issues (Linac to end stations) need to be addressed and will likely have serious impact (e.g. roof over LEIR)

Status and conclusions Beamline design needs more work  Depends also on users’ requirements Experimental areas, BI, CO, integration not yet addressed Operational scenarios should also be envisaged between potential users and accelerator specialists -> required instrumentation and handles… Aim to have a comprehensive descriptive document by end of 2016 covering the entire facility from source to end stations.