| | 1 | = The LhARA initiative; harnessing laser-driven ions for biomedical application = |
| | 2 | **Abstract** submitted to [https://spie.org/EOO27/conferencedetails/applying-laser-driven-particle-acceleration Applying Laser-driven Particle Acceleration (ALPA)] at [https://spie.org/conferences-and-exhibitions/optics-and-optoelectronics SPIE Optics and Optoelectronics 2027] |
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| | 4 | //Kenneth Long // for the collaboration |
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| | 6 | == Abstract == |
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| | 8 | The Laser-hybrid Accelerator for Radiobilogical Applications is conceived as a novel, uniquely-flexible facility dedicated to the study of the biological impact of proton and ion beams. It is the central pilar of the LhARA collaboration's initiative to: |
| | 9 | * Deliver a systematic and definitive radiation biology programme; |
| | 10 | * Prove the feasibility of laser-driven hybrid acceleration; and |
| | 11 | * Lay the foundations for the transformation of clinical practice of ion beam therapy. |
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| | 13 | The development of a systematic programme of radiobiology centred on the proof-of-principal beam-line, "PoPLaR", on the SCAPA facility at |
| | 14 | Strathclyde University is the second pilar of the LhARA intiative. The third pilar of the initiative is the creation of an eco-system in |
| | 15 | which co-creation, co-investment and international collaboration deliver the technologies required to transform ion-beam therapy. |
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| | 17 | The design of the LhARA facility will be described and the status of, and first results from, the PoPLaR beam line will be summarised. Progress in the development of the industrial partnership will also be reviewed. |
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| | 20 | Laser-driven ion sources offer potential advantages in a range of disciplines, including radiotherapy, but the beams created have a large divergence, creating significant challenges for conventional technologies that often rely on asymmetric focusing and require strong magnetic fields. The Laser-hybrid Accelerator for Radiobiological Applications (LhARA) proposes the use of a Gabor lens as a symmetric focusing system to capture the laser-driven beam. A Gabor lens uses the electrostatic field of a confined electron plasma to focus positively charged particles. The focusing strength is determined by the electron density and length. |
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| | 22 | This contribution reports results from a Gabor lens testbench at Swansea University. A Penning-Malmberg trap, comprising a radially confining solenoid and axially confining electrodes, is used to confine an electron plasma produced through seeding background CO2 gas ionisation with an electron gun. Experimental results have explored rotating-wall techniques, oscillating electric fields and the introduction of a dimple potential. The combination of the dimple potential and oscillating fields has improved plasma stability. Peak densities of approximately 8 × 10¹⁴ m⁻³ have been achieved, approaching the design target for the proposed LhARA lens (4 x 10^15 m-3). |
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| | 24 | Complementary three-dimensional particle-in-cell simulations using WarpX are being developed to support the interpretation and optimisation of experimental measurements. In parallel, preliminary particle-tracking studies indicate that the experimentally achieved plasma density could provide sufficient focusing for positrons, motivating further simulation and experimental validation. |
| | 25 | Together, these results represent progress towards a stable, sufficiently dense plasma, marking crucial steps in the development of a Gabor lens for the capture and transport of laser-driven ion beams. |
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| | 27 | == Summary for display in the program == |
| | 28 | Laser-driven ion beams have significant potential for future applications in radiobiology and particle therapy, but their large divergence makes efficient capture and transport challenging. A Gabor lens offers a symmetric focusing solution using the electric field of a confined electron plasma. This contribution presents experimental progress at Swansea University in generating and stabilising the plasma required for such a lens, including improvements achieved using oscillating electric fields and a dimple potential. Complementary WarpX simulations support the development of a practical focusing system for applications such as LhARA. |
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| | 30 | == Biographical information == |
| | 31 | Calvin Dyson is a third-year PhD researcher at Imperial College London and a member of the LhARA (Laser-hybrid Accelerator for Radiobiological Applications) collaboration under the supervision of Professor Kenneth Long. His research spans several areas across LhARA, with a primary focus on understanding and modelling the experimental results from the Gabor lens testbench at Swansea University. This involves employing WarpX to investigate electron plasma confinement using three-dimensional particle-in-cell simulations. His other contributions within the collaboration include beamline optimisation and characterisation for the PoPLaR experiment, as well as simulations and data analysis for ion-acoustic diagnostics. His research contributes to the development and characterisation of the focusing technologies and diagnostics required to realise LhARA's radiobiological applications. |
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