Ghislain Roy

presenting work of

C. Carli, A. Garonna, D. AblerD. Kuchler, V. Toivanen, S. Myers, M. Dosanjh,

and many others

OPENMED - BioLEIR

The New CERN Initiatives

1. Medical Accelerator DesignCoordinate 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

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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 - MotivationNeed 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

LEIRPart of the SPS and LHC injector chain,

Gets heavy ion beams (Pb54+) 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 12C or 16O 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

Lin

ac 3

Lin

ac 2

Linac 4 LEIR

South Hall

LEIR

Circumference ~78 m=> energy reach suitable for studies of interest for hadrontherapy

Transfer tunnelProposed new extraction

and extraction line

Introduction – Present LEIRMachine Layout

E-Cooling

Ejection

D≠10m

D≠0

D=0

Ejectionkicker

Quadrupole doublet

dipole

RF

D=0

Inje

ctio

n

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 modificationsTransfer lines - from Linac3

- towards the PS

Injectionline

Ejection linefor PS transfer

New ejectionchannel

LEIR shielding

wall

New transfer lineto experiment

PS shielding wall

Source (H2+ -- 8+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 studied1. 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

Advantages Disadvantages

• 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 …

Species C N O Ne

Intensity 1.4 109 0.4 109 1.1 109 0.25 109

High energy RFQ

Advantages Disadvantages

• 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)

Advantages Disadvantages

• 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

Advantages Disadvantages

• 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. C6+ @ 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 12C6+ 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 knock-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

3rd 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 3rd 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 acceptshigh chromaticities

LEIR: Q’ = 9 in horizontal plane for Hardt condition

LEAR: Q’ = -8 in vertical due to limitedsextupolar strengths

Use of sextupole magnets and bendingmagnet pole face windings (PFWs)

Phase space plot at the position of the electrostatic septum for LEIR latticeTwo particles with different momenta

ES

MSMS

Septa Electrostatic Magnetic

Physical Length 86 cm 120 cm

Effective Length 66 cm 100 cm

Septum Thickness 0.1 mm 10 mm

Field Strength 7 MV/m 0.5 T

Kick (400 MeV/u C6+) 3.4 mrad 80 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 Hor. @ 440 MeV/u Vert. @ 70 Mev/u

Pencil Beam : 5-10mm FWHM Broad Beam : 50 x 50 mm2

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 withupdated information(particle fluxes, vacuumchambers 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 2.5 107 O ions

per seconds at Ek=250 MeV/n

Am

bie

nt D

ose

-Eq

Rate

[μ

Sv/h

]

Experimental Area Target station and biolab to be defined and constructed

Patient treatment and live animal studies are excludedLive 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 fluxesand/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.