Performance of a low gain avalanche detector in a medical linac and characterisation of the beam profile

TL;DR

This paper demonstrates that low gain avalanche detectors can precisely measure charged particle fluences in medical linacs, offering high spatial and temporal resolution, enabling detailed beam profile characterization and single-pulse charge measurement.

Contribution

The study introduces the application of low gain avalanche detectors in medical linacs, achieving unprecedented spatial and temporal resolution for beam profiling and pulse analysis.

Findings

Single particles observed with 50 ps time resolution

Spatial precision twenty times finer than ionising chambers

Ability to measure charge from a single linac pulse

Abstract

Low gain avalanche detectors can measure charged particle fluences with high speed and spatial precision, and are a promising technology for radiation monitoring and dosimetry. A detector has been tested in a medical linac where single particles were observed with a time resolution of 50\,ps. The integrated response is similar to a standard ionising chamber but with a spatial precision twenty times finer, and a temporal precision over 100 million times better, with the capability to measure the charge deposited by a single linac pulse. The unprecedented resolving power allows the structure of the $\sim 3\,\mu$s linac pulses to be viewed and the 350\,ps sub-pulses in the train to be observed.