Monitoring electron energies during FLASH irradiations
(2021) In Physics in Medicine and Biology 66(4).- Abstract
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... (More)
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.
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- author
- Berne, Alexander ; Petersson, Kristoffer LU ; Tullis, Iain D.C. ; Newman, Robert G. and Vojnovic, Borivoj
- publishing date
- 2021-02-21
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Dosimetry, Electron beam energy, Flash, Linac, Pre-clinical irradiation, Pre-clinical radiotherapy, Radiobiology
- in
- Physics in Medicine and Biology
- volume
- 66
- issue
- 4
- article number
- 045015
- publisher
- IOP Publishing
- external identifiers
-
- scopus:85101843836
- pmid:33361551
- ISSN
- 0031-9155
- DOI
- 10.1088/1361-6560/abd672
- language
- English
- LU publication?
- no
- additional info
- Publisher Copyright: © 2021 Institute of Physics and Engineering in Medicine.
- id
- f92e29a7-1fee-4a46-b734-a329d3984006
- date added to LUP
- 2021-11-03 18:20:33
- date last changed
- 2024-06-15 19:44:28
@article{f92e29a7-1fee-4a46-b734-a329d3984006,
abstract = {{<p>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.</p>}},
author = {{Berne, Alexander and Petersson, Kristoffer and Tullis, Iain D.C. and Newman, Robert G. and Vojnovic, Borivoj}},
issn = {{0031-9155}},
keywords = {{Dosimetry; Electron beam energy; Flash; Linac; Pre-clinical irradiation; Pre-clinical radiotherapy; Radiobiology}},
language = {{eng}},
month = {{02}},
number = {{4}},
publisher = {{IOP Publishing}},
series = {{Physics in Medicine and Biology}},
title = {{Monitoring electron energies during FLASH irradiations}},
url = {{http://dx.doi.org/10.1088/1361-6560/abd672}},
doi = {{10.1088/1361-6560/abd672}},
volume = {{66}},
year = {{2021}},
}