Monitoring electron energies during FLASH irradiations
| Autor: | Iain D. C. Tullis, Alexander Berne, Kristoffer Petersson, Borivoj Vojnovic, R G Newman |
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| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Paper
Materials science Electrons Electron FLASH Linear particle accelerator 030218 nuclear medicine & medical imaging 03 medical and health sciences 0302 clinical medicine Optics LINAC Radiology Nuclear Medicine and imaging Computer Simulation Irradiation Radiometry pre-clinical radiotherapy Range (particle radiation) Radiological and Ultrasound Technology dosimetry business.industry electron beam energy radiobiology 030220 oncology & carcinogenesis Cathode ray Physics::Accelerator Physics Radio frequency Particle Accelerators business pre-clinical irradiation Monte Carlo Method Energy (signal processing) Beam (structure) |
| Zdroj: | Physics in Medicine and Biology |
| ISSN: | 1361-6560 0031-9155 |
| Popis: | When relativistic electrons are used to irradiate tissues, such as during FLASH pre-clinical irradiations, the electron beam energy is one of the critical parameters that determine the dose distribution. Moreover, during such irradiations, linear accelerators (linacs) usually operate with significant beam loading, where a small change in the accelerator output current can lead to beam energy reduction. Optimisation of the tuning of the accelerator’s radio frequency system is often required. We describe here a robust, easy-to-use device for non-interceptive monitoring of potential variations in the electron beam energy during every linac macro-pulse of an irradiation run. Our approach monitors the accelerated electron fringe beam using two unbiased aluminium annular charge collection plates, positioned in the beam path and with apertures (5 cm in diameter) for the central beam. These plates are complemented by two thin annular screening plates to eliminate crosstalk and equalise the capacitances of the charge collection plates. The ratio of the charge picked up on the downstream collection plate to the sum of charges picked up on the both plates is sensitive to the beam energy and to changes in the energy spectrum shape. The energy sensitivity range is optimised to the investigated beam by the choice of thickness of the first plate. We present simulation and measurement data using electrons generated by a nominal 6 MeV energy linac as well as information on the design, the practical implementation and the use of this monitor. |
| Databáze: | OpenAIRE |
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