Developments and Optimisation of the University of Birmingham Cyclotron

Dr Tony Price-Ford, Andrew Nixon, Stuart Hill, Dr Spyros Manolopolous, Prof. Stuart Green, and Prof. David ParkeroPAC International Conference, Seville07/10/2015Developments and Optimisation of the University of Birmingham Cyclotron

Scanditronix MC40 CyclotronThe Scanditronix MC40 was brought at auction from the Veterans Affairs Medical Centre, Minneapolis in 2002 and following transfer and commissioning has been operational since 2004Capable of accelerating beams of:Protons (3-38 MeV)Deuterons (5.5-19 MeV)Helium-3 (9-53 MeV)Helium-4 (11-37 MeV)Currents of fA to A are possible

07/10/2015oPAC International Conference, Seville, Spain, 20152Past and Current UsesIsotope productionThin layer activation studiesCreation of PEPT tracers (F-18Water & Solid beads)RadiobiologyRb-81 production for medical purposesAccelerated radiation damagetests for LHCMetallurgyNuclear PhysicsDevelopment & testing ofnovel proton CT device

07/10/2015oPAC International Conference, Seville, Spain, 20153Typical day on the cyclotronTwo shiftsSun-Monday 13:00-21:00Monday-Friday 6:00-13:00Between 6:00-9:00 every morning PEPT isotopes are created for the PEPT group to allow industrial developmentsAfter 16:00 every evening Rb-81 is produced for medical purposes. This has a half life of 4.6 hours and decays to Kr-81m gas. This is collected each evening and distributed to NHS centres around the country for imaging lung functionalityBetween these times the cyclotron is available for research purposes. To maximise the impact of this research this window must be optimally utilised07/10/2015oPAC International Conference, Seville, Spain, 20154Beam Setup and QARF tuned for appropriate frequency. Currents in main coils, 8 concentric trim coils and 4 sets of harmonic centring coils adjusted to optimise internal beamBeam extracted by adjusting deflector voltageCyclic process until stable coherent beam is found on FC outside the cyclotronSwitching magnet then used to direct beam down one of 12 beam linesThis process usually takes ~30 minutes.Rest of the talk will focus on developments made to the research beam line to reduce setup and QA times where possible07/10/2015oPAC International Conference, Seville, Spain, 20155Beam FlatteningRelatively quick & simple to achieve a small (1-2cm) diameter uniform beamFor anything much larger than this the beam is defocused using two sets of Quadrupole magnetsAchieving a large (5 cm) uniform beam in this way can be challenging and time consumingTypically 45 mins of optimising would yield a beam with 20% dose uniformity

Dose distribution collected on EBT3 GaFChromic film for a defocued 36 MeV beam07/10/2015oPAC International Conference, Seville, Spain, 20156Beam Flattening SystemA beam flattening system has been developed in conjunction with Stuart Hill (Masters student with Open University)Aims of the flattening system were to:Achieve a 5 cm beam uniform to greater than 90%Reduce the beam energy of the 36 MeV beam by < 1 MeVReduce the setup timeMake the beam more reproducible day-to-dayDecided to use a single scattering system with a large throw distance to minimise material budget in the beamFollowing preliminary measurements Ta chosen as the thin scattering foil as gave the largest angle per energy loss07/10/2015oPAC International Conference, Seville, Spain, 20157Beam Flattening System

Plunger to allow complete removal of system from beam when not requiredDouble collimator system to ensure parallel beamBNC connectors to measure current to scattering foil and collimators80 m Ta foil to scatter beam fixed to final collimator3500mm to nozzle300mm from Quads300mm separation07/10/2015oPAC International Conference, Seville, Spain, 20158The scattering foil for both energy beams yields a 5 cm beam which is uniform to > 90% over whole area. The time to setup this beam is significantly reduced (now 15 mins not 45 mins) due to optimising and then scattering a small beam. Beam Flattening System29 MeV Beam36 MeV beam

Certainly reproducible! But need to understand why we see same pattern all the time even when we change the energy of the beam.07/10/2015oPAC International Conference, Seville, Spain, 20159Collimation SystemPreviously on this beam line the options were a 10, 20, or 50 mm diameter beamTo change between these required the breaking of the vacuum and a complete change of nozzle.Work with Andrew Nixon (Clinical Scientist at QEHB and Masters student) led to the development of a new nozzle which better mimics a clinical environment and allows for the rapid change of collimators.

07/10/2015oPAC International Conference, Seville, Spain, 201510Collimation System

Wide range of collimators available, any shape can be cut07/10/2015oPAC International Conference, Seville, Spain, 201511Collimation System

07/10/2015oPAC International Conference, Seville, Spain, 201512Measuring the beam energyTo ensure a clean, coherent beam is extracted which has not scattered down the beam pipe or interacted with anything left in the beam pipe from previous experiments a Bragg Peak is reconstructedVarious known thicknesses of Perspex are inserted between two ionisation chambers (Transmission Chamber upstream and Markus Chamber downstream) and the ratio of charge collected calculatedAs the proton slows the signal collected in the Markus Chamber increases relative to the Transmission Chamber and the Bragg Peak is mapped outConventional method required the opening of a large mechanical door and breaking of interlocks to change the Perspex. A typical Bragg Peak took 75+ minutes to measure

An example BP where a small collimator had been left upstream from previous experiments07/10/2015oPAC International Conference, Seville, Spain, 201513Automated PeakFinderUsing an old Scanditronix RFA-300 controller we can now use a 1D scanner to change the Perspex thicknessA graduated piece of Perspex with 100 m steps around the Bragg Peak Still uses transmission and Markus chambers so read out systems unchangedMajor time now is collecting data not setting up!

07/10/2015oPAC International Conference, Seville, Spain, 201514Automated PeakFinder

36 MeV uses a 4 mm block of Perspex to get additional rangeMeasurements with automated arm took just 26 minutes and the interlock was broken just once during the 29 MeV data taking to add a 50 m Perspex shim to improve resolution of Bragg PeakExcellent agreement of 29 MeV methods shows density of Perspex is the same and we can still use all current MC simulations!07/10/2015oPAC International Conference, Seville, Spain, 201515Alignment Tool07/10/2015oPAC International Conference, Seville, Spain, 201516A lot of time is currently spent aligning different apparatus to the beamNew collimator insert is a self contained laser pointerProject small laser point which coincides exactly with the centre of the beamWill make alignment much faster and easier!New Table

Metamorphasis07/10/2015oPAC International Conference, Seville, Spain, 201517Future Ideas Spot Scanning!

2D contoller2D Wellhofer HeadscannerKindly donated by Dundee Hospital07/10/2015oPAC International Conference, Seville, Spain, 201518ConclusionsMC40 Cyclotron is extremely flexible and has a varied workload. Research time is limited to ~7 hours in the dayWe have developed the research beam line to be more user friendly and faster to set up to optimise the use of this timeBeam flattening 45 mins15 minsEnergy Measurement 75 mins 26 minsChanging of collimators 30 mins 1 min (every change)Alignment Tool 20-30 mins 10 minsTotal saving of 90-100 mins + every collimator changeLeads to 35+% more useable time in a day!!Future plans to develop spot scanning as well as scattered beam are very interesting!

07/10/2015oPAC International Conference, Seville, Spain, 201519Acknowledgments07/10/2015oPAC International Conference, Seville, Spain, 201520Would like to thank the organisers for assistance with attending the conference.This work was supported by the Wellcome Trust translational grant 098285 (PRaVDA).Supported by the H2020 project AIDA-2020, GA no. 654168.

Thank you for listening!Any Questions?07/10/2015oPAC International Conference, Seville, Spain, 201521Dr Price-Ford with assistance from Sandcross Primary School, Surrey07/10/201507/10/2015Children In Space What does the future hold for young scientists in the 21st Century?