--- title: "Cyclotron Info — How Cyclotrons Work, Design Rules & Amateur Builds" canonical: https://cyclotroninfo.com/ description: "The open reference for understanding, designing, and documenting small cyclotrons — design rules, calculators, safety and legal guidance, literature, and the amateur build census." generated: 2026-11-09 note: "Markdown rendering of the canonical HTML page, generated at build for AI assistants and text tools. Figures and interactive elements are described, not reproduced. On Design Guide rules the source quote, this site's paraphrase and this site's editorial note are labelled separately and must not be conflated." licence: "Datasets CC BY 4.0, census snapshot CC BY-NC 4.0 (https://cyclotroninfo.com/data/); cite as Cyclotron Info, cyclotroninfo.com" --- # Cyclotron Info The open reference for understanding, designing, and documenting small cyclotrons. Built for cyclotron enthusiasts — students, hobbyists, amateur builders, and anyone curious about the machine that started high-energy physics. **Why this site?** Practical knowledge about small cyclotrons is scattered across ninety years of journal papers, out-of-print books, student theses, defunct project pages, institutional reports, and fifty-one bodies of state regulation. This project gathers it into one place — organized, cited, and source-checked, with its review status made explicit — so the next builder starts from the literature instead of from scratch. ![A 1939 cyclotron in a laboratory hall: a grey magnet with round coil tanks above and below the chamber at left, a tapered section leading right to a long cylindrical vacuum tank with round ports, pumps and copper piping beneath and beside it.](https://cyclotroninfo.com/images/home/60-inch-cyclotron-march-1939.jpg) *Figure caption:* The Crocker 60-inch cyclotron at the Berkeley Radiation Laboratory, photographed 20 March 1939: magnet at left, vacuum tank and pumps at right. Photo: Lawrence Berkeley National Laboratory, via the [US National Archives](https://catalog.archives.gov/id/39147342) (record 39147342, use restriction: Unrestricted; held in the Department of Energy record group; non-commercial use). ## What would you like to do? ### Understand how a cyclotron works Why one fixed-frequency voltage keeps accelerating an ion as it spirals outward, what sets the energy a magnet can reach, and where the idea came from. - [How a cyclotron works](https://cyclotroninfo.com/learn/how-a-cyclotron-works/) - [Virtual Cyclotron Laboratory](https://lab.cyclotroninfo.com/) — set the controls, watch the ions (hosted) - [Guided exercises](https://cyclotroninfo.com/learn/exercises/) - [History](https://cyclotroninfo.com/learn/history/) - [Glossary](https://cyclotroninfo.com/learn/glossary/) ### Explore the world’s cyclotrons 1,564 machines in 92 countries on a map and list — research, medical-isotope, therapy and teaching machines — and the ones you can visit. - [Map and directory](https://cyclotroninfo.com/locations/) - [Cyclotrons you can visit](https://cyclotroninfo.com/locations/#visiting) - [What they are used for](https://cyclotroninfo.com/learn/applications/) - [Who builds them](https://cyclotroninfo.com/learn/cyclotron-industry/) ### Decide whether to build one What the 27 documented amateur and school builds cost, how long they took, and that 8 of them have reached beam — read before buying iron. - [Should you build one at all?](https://cyclotroninfo.com/learn/should-you-build-one/) - [What building one takes](https://cyclotroninfo.com/learn/so-you-want-to-build-one/) - [Safety](https://cyclotroninfo.com/learn/safety/) - [Is it legal where you live?](https://cyclotroninfo.com/legal/) - [What others built](https://cyclotroninfo.com/builds/) ### Design a machine Turn a budget, a space and a power outlet into a costed, planning-grade design, then size each subsystem yourself. - [Cyclotron Builder](https://build.cyclotroninfo.com/) — planning grade; hosted - [Choosing your machine](https://cyclotroninfo.com/learn/choosing-your-machine/) - [Calculators and every other tool](https://cyclotroninfo.com/tools/) - [Builder FAQ](https://cyclotroninfo.com/learn/faq/) — half built and stuck? start from the symptom ### Research the engineering 2,199 sourced design rules by subsystem, each with its formula and citation; 327 library documents; and the free modelling tools that check a design. - [Design Guide](https://cyclotroninfo.com/design-guide/) - [Subsystem deep dives](https://cyclotroninfo.com/learn/#deep-dives) - [Library](https://cyclotroninfo.com/library/) - [Modeling tools](https://cyclotroninfo.com/learn/modeling-tools/) ### Study or work in the field Accelerator career paths from operator to physicist with the credential each actually needs, the university programs that teach it, and a self-study route. - [Accelerator careers](https://cyclotroninfo.com/careers/) - [University programs](https://cyclotroninfo.com/careers/university-programs/) - [How to learn to build one](https://cyclotroninfo.com/learn/study-path/) - [Current openings](https://cyclotroninfo.com/careers/jobs/) - [News and job boards](https://cyclotroninfo.com/news/) - **1,564** [cyclotrons mapped](https://cyclotroninfo.com/locations/) - **92** [countries](https://cyclotroninfo.com/locations/) - **2,199** [sourced design rules](https://cyclotroninfo.com/design-guide/) - **327** [library documents](https://cyclotroninfo.com/library/) - **27** [documented amateur builds](https://cyclotroninfo.com/builds/) - **7** [calculators](https://cyclotroninfo.com/calculators/) Census figures are from the quarterly directory snapshot of 2026-10-04. Starting a design? Open the Design Guide at [level 1](https://cyclotroninfo.com/design-guide/level/1/) — the 42 rules that govern whether any small cyclotron is feasible — and widen to the next level as the design firms up. Or start with the machines themselves, in the [amateur builds census](https://cyclotroninfo.com/builds/). ## All sections ### [Learn](https://cyclotroninfo.com/learn/) How cyclotrons work, their history, what they are used for, safety fundamentals, a realistic starter path — and subsystem deep dives from magnet design to beam dynamics. ### [Design Guide](https://cyclotroninfo.com/design-guide/) 2,199 sourced design rules for small cyclotrons — magnet, RF, vacuum, ion source, dees, chamber, extraction, and beam measurement — filterable by subsystem, each with formula and citation. ### [Calculators](https://cyclotroninfo.com/calculators/) Interactive calculators for energy, field, and radius; path length and turn count; vacuum requirements; coil geometry; magnet power; lid deflection; RF matching — each with the math explained. ### [Legal](https://cyclotroninfo.com/legal/) Can you legally build and run a cyclotron? Federal rules and a jurisdiction-by-jurisdiction survey of all 50 US states, with an interactive map. ### [Library](https://cyclotroninfo.com/library/) An annotated bibliography of cyclotron and accelerator literature — 327 documents rated for relevance to small-machine builders, from 1930s classics to modern references, with the public-domain construction reports hosted here. ### [Amateur Builds](https://cyclotroninfo.com/builds/) A census of documented home and school cyclotron builds, successful or stalled, with specs, status, and sources. ### [Worldwide Cyclotron Directory](https://cyclotroninfo.com/locations/) Where the world’s cyclotrons are: research, medical, and university machines on a filterable map and list — and which ones you can tour. ### [News & Jobs](https://cyclotroninfo.com/news/) Automatically aggregated cyclotron and accelerator news, plus a directory of the job boards where accelerator posts appear.