[Paper Review] Applications of Particle Accelerators

Suzanne Sheehy|arXiv (Cornell University)|Jul 14, 2024

Particle accelerators and beam dynamics4 citations

TL;DR

This paper provides a comprehensive overview of non-particle-physics applications of particle accelerators, highlighting their critical roles in medicine (e.g., radiotherapy and proton therapy), industry (e.g., electron beam processing and material modification), and scientific research (e.g., synchrotron light sources and neutron spallation sources). It emphasizes the societal impact of accelerators, with over 50,000 units worldwide generating a $5 billion annual industry, and discusses challenges related to cost, sustainability, and equitable access.

ABSTRACT

Of the tens of thousands of particle accelerators in operation worldwide, the vast majority are not used for particle physics, but instead for applications. Some applications such as radiotherapy for cancer treatment are well-known, while others are more surprising: food irradiation using electron beams, or the hardening of road tarmac. The uses of particle beams are constantly growing in number including in medicine, industry, security, environment, and cultural heritage preservation. This lecture aims to give a broad sweep of the many uses of particle accelerators, covering technologies ranging in size from a few centimetres for industrial electron linacs through to large synchrotron light sources of hundreds of metres circumference operating as national and international facilities. We finish by discussing some of the challenges facing accelerators used in wider society.

Motivation & Objective

• To document and categorize the wide range of non-academic applications of particle accelerators globally.
• To highlight the societal and economic impact of accelerator technologies beyond fundamental physics research.
• To identify key challenges in cost, sustainability, material use, and equitable access to accelerator-based technologies.
• To promote awareness among accelerator scientists of the broader societal roles their technologies play.
• To encourage responsible development and deployment of accelerator technologies through life-cycle and ethical considerations.

Proposed method

• Systematic review and synthesis of existing literature and data on accelerator applications, including reports from CERN, the U.S. Department of Energy, and international facilities.
• Analysis of global accelerator distribution by application type using data from 2019, categorizing accelerators into medical, industrial, and research-based uses.
• Examination of technical principles behind key applications, such as bremsstrahlung X-ray production in radiotherapy linacs and neutron spallation in target materials.
• Evaluation of accelerator technologies including electron linacs, synchrotron light sources, and spallation neutron sources, with focus on beam energy, intensity, and control mechanisms.
• Assessment of environmental and ethical challenges, including use of rare earth metals, SF6 and helium usage, and life-cycle impacts of components.
• Incorporation of case studies from major facilities such as the ISIS neutron source to illustrate real-world scientific and industrial applications.

Figure 1: Distribution of accelerators worldwide by common applications in 2019. Data sourced from Ref. [ 2 ] .

Experimental results

Research questions

• RQ1 What are the primary non-physics applications of particle accelerators, and how widespread are they globally?
• RQ2 How do accelerator-based technologies contribute to medical treatments such as cancer radiotherapy and proton therapy?
• RQ3 What are the key technical and operational principles enabling industrial and scientific applications of particle beams?
• RQ4 What are the major sustainability and ethical challenges associated with the deployment and operation of particle accelerators in society?
• RQ5 How can equitable access to accelerator-based medical technologies be improved, especially in low- and middle-income countries?

Key findings

• Over 50,000 particle accelerators are in operation worldwide, with more than half used for industrial applications and most of the remainder for medical purposes.
• The global market for medical and industrial accelerators was valued at $5 billion USD annually in 2018, with sustained growth even during economic downturns.
• Radiotherapy using linear accelerators is used in approximately 50% of curative cancer treatments, with modern techniques like IMRT and VMAT improving tumor targeting and reducing healthy tissue damage.
• Proton and ion therapy facilities now treat over 100,000 patients annually, offering superior dose conformity and reduced side effects compared to photon therapy.
• Synchrotron light sources and spallation neutron sources enable advanced materials and biological research, including protein structure analysis and non-destructive testing of critical infrastructure.
• Key challenges include high costs, reliance on rare earth elements (e.g., niobium, neodymium), use of greenhouse gases like SF6, and declining helium availability for cryogenic systems.

Figure 2: Figure showing overall increase in cancer deaths over time by cancer type, from OurWorldinData under CC-BY license.