Early experience and commissioning of the Manchester research beamline for pencil beam scanned protons at ultra-high dose rates

Aylward, Jack; Taylor, M.; Kirkby, K.; Mackay, R.

Abstract

Background and Aims: The University of Manchester research beamline at the Christie Proton Beam centre consists of a fixed horizontal beamline with a Varian ProBeam scanning nozzle, enabling delivery of pencil beam scanned (PBS) protons from 70–245 MeV. Ultra-high dose rate (UHDR) PBS can be achieved using requested nozzle currents of up to 83.5 nA at 245 MeV. The early experience of characterising this beamline for UHDR delivery is discussed, and energy-dependent dose rate capabilities of the beamline are presented.

Methods: A Multi-Strip Ionisation Chamber (MSIC) was used to control the beam, calibrated against a PTW Advanced Markus ion chamber traceable to the National Physical Laboratory, UK. Beam profile measurements were obtained using an IBA LYNX detector. Energy dependent intraspot dose rates were measured using a PTW microDiamond in a PTW Water Phantom.

Results: Energy dependent peak dose rates of 120 Gy/s were measured in the centre of a 245 MeV spot with spot size σx=6.6 mm and σy=4.6 mm at the focal plane.

Conclusions: The Christie Proton Beam Centre research beamline is capable of delivering PBS ultra-high dose rate (FLASH) with maximum intraspot dose rates of up to 120 Gy/s in the existing beamline configuration.

• Journal Article Type: Other
• Online Publication Date: Feb 25, 2022
• Publication Date: 2022-02
• Deposit Date: Aug 30, 2024
• Journal: Physica Medica
• Print ISSN: 1120-1797
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 94
• Issue: Supplement
• Pages: S64
• DOI: https://doi.org/10.1016/s1120-1797%2822%2901577-0
• Public URL: https://uwe-repository.worktribe.com/output/12830036