Cyclotron Info

Amateur Builds

This is a census of documented amateur cyclotrons: machines designed and built by individuals, high-school teams, or small undergraduate groups outside professional accelerator programs. An entry qualifies if the build itself is documented — a project site, thesis, conference paper, or credible press account — not merely rumored. Design studies count when they left a public record; unverifiable claims are noted as such.

Few of these projects reach beam, and the reasons repeat across seven decades: a cyclotron demands a ton-scale homogeneous magnet, high vacuum, a kilovolt-level RF resonator, a working ion source, and diagnostics — every subsystem at near-professional standard before anything at all happens. Builders at the 2010 amateur cyclotron conference estimated two to three years of work and roughly $125,000 in parts if bought new (Symmetry, Aug 2010), which is why nearly every successful machine leans on donated magnets, surplus hardware, and patient scrounging. The entries below are presented in a uniform format, in rough chronological order, with each machine's claims traceable to the linked sources.

17 documented projects · 8 with a demonstrated or routinely operated beam.

  1. El Cerrito High School Cyclotron

    Four students with physics teacher Ben Siegel, El Cerrito High School, California 1947

    operated USA

    Magnet ≈1 t (one-ton) welded soft-steel yoke
    RF frequency 20 MHz (reported), ≈1.5 kW
    Particle protons
    Energy “million-electron-volt” claimed in period press; unverified

    The earliest well-documented school-built cyclotron, constructed in about three months for roughly $500 and featured in Physics Today and Popular Science in 1947. The students operated the one-ton machine by remote control from a plywood panel in a closet-sized room, and the Research Corporation waived royalties on the Lawrence cyclotron patents it infringed. Contemporary press reported the machine running at 20 MHz, but no beam measurements survive, so the million-electron-volt figure should be read as a period claim.

    Popular Science, Nov 1947 (Modern Mechanix scan)Popular Science article scan (RF Cafe)Symmetry: The do-it-yourself cyclotron (2010)

  2. Fort Wayne High School Cyclotron

    Three high-school students, Fort Wayne, Indiana 1951

    outcome unknown USA

    In 1951 three students remodeled their high-school basement into a cyclotron laboratory and were already at work on the accelerator by the time the principal found out. The group kept careful engineering notes that later amateur builders cite as an early blueprint, and two of the students went on to work at Fermilab. No surviving documentation confirms whether the machine ultimately accelerated ions.

    Symmetry: The do-it-yourself cyclotron (2010)

  3. Central High School Cyclotron

    Successive student teams (L. Zuckerman, N. Ostroff, J. Horowitz and others; later S. Goldwasser and others), Central High School, Philadelphia 1958 – c. 1970

    outcome unknown USA

    Pole diameter 178 mm (7 in)
    Field ≈2 T (20 kG) reported at full excitation
    RF frequency ≈7 MHz initially, later ≈20 MHz
    Particle protons (intended)
    Energy ≈1 MeV theoretical; no measured beam

    A cyclotron built and rebuilt by roughly three generations of Philadelphia high-school students between 1958 and about 1970, documented in a detailed retrospective by one of the later participants. The 7-inch machine was theoretically capable of about 1 MeV, but the account itself doubts a real proton beam was ever achieved; the best evidence of operation was a marginal exposure of dental X-ray film.

    The Central High School Cyclotron (repairfaq.org)

  4. Stuyvesant High School Cyclotron

    Student Cyclotron Committee, Stuyvesant High School, New York City early 1960s

    outcome unknown USA

    Stuyvesant students organized a Cyclotron Committee with specialized teams for the electromagnet, vacuum chamber, and RF system, collecting donations that included a half-ton of steel and five miles of copper wire at a project cost of roughly $10,000. A 1962 school publication suggested the machine was completed, but a retrospective in the school's own newspaper found no evidence the project actually reached completion.

    The Stuyvesant Spectator retrospective

  5. Niell Cyclotron I

    Fred Niell (high-school student, home-built) c. 1993–1994

    beam demonstrated USA

    RF frequency resonance observed at 2.2–2.3 MHz
    Particle residual-air ions (mostly nitrogen)
    Vacuum small diffusion pump backed by a rotary pump

    A cyclotron designed and built at home by a high-school student, set up in the room next to his bedroom, with every component — magnet, RF amplifier, vacuum gauges — of his own construction. Running on residual air rather than an isolated gas species, it demonstrated cyclotron mass resonance with a clear output peak at 2.2–2.3 MHz consistent with nitrogen ions and their harmonics. The associated science-fair project won the grand prize at the 1994 International Science and Engineering Fair.

    Fred's World of Science: Cyclotron I (archived)Symmetry: The do-it-yourself cyclotron (2010)

  6. Niell Cyclotron II

    Fred Niell (high-school student, home-built) 1994–1995

    beam demonstrated USA ≈70 keV

    Field ≈0.67 T (6.7 kG, measured)
    RF frequency 0.5–16 MHz variable; H⁺ resonance observed at 10 MHz
    Particle protons, helium ions
    Energy ≈70 keV (H⁺ at measured resonance, r = 5.7 cm)
    Vacuum diffusion pump with molecular-sieve trap

    A second, more research-oriented machine built the following school year, fixing the shortcomings of the first: a variable-frequency RF system (0.5–16 MHz) driven by a tube push-pull amplifier allowed resonance mapping of more than one ion species. Measured resonance peaks for hydrogen and helium matched prediction within about 2% once the magnet coil count was corrected, corresponding to roughly 70 keV protons. The machine was left at the school when the builder went to college and was later dismantled for parts.

    Fred's World of Science: Cyclotron II (archived)Symmetry: The do-it-yourself cyclotron (2010)

  7. Rutgers 9-Inch Cyclotron (prototype)

    Tim Koeth and Stu Hanebuth, undergraduates at Rutgers University 1995–1999

    beam demonstrated USA

    Pole diameter 229 mm (9 in), Varian V-3400 NMR magnet
    Field 0.889 T (8.89 kG) operating; 1.2 T maximum
    RF frequency 13.56 MHz
    Particle protons
    Energy up to ≈50 nA proton current at the chamber periphery

    The feasibility prototype for the later 12-inch machine, built around a repurposed Varian NMR magnet turned on its side, with a fixed 13.56 MHz industrial-band RF system setting the 0.889 T operating field. Successful resonance runs in 1999 showed a strong proton current at the predicted field, with beam detected at up to about 50 nA at the periphery. Its results justified moving to a 12-inch magnet with a 1 MeV design goal.

    Koeth cyclotron site: 9-inch prototypeKoeth cyclotron site (main)

  8. Rutgers 12-Inch Cyclotron

    Tim Koeth, Stu Hanebuth, and successive Rutgers undergraduates 1995–present

    operated USA 800 keV

    Pole diameter 305 mm (12 in)
    Field 1.2 T (12 kG) design
    RF frequency ≈18 MHz (design)
    Particle protons
    Energy 800 keV, 200 nA demonstrated by 2006; 1 MeV capability; tens of µA after 2012 PIG source upgrade

    The best-documented amateur-origin cyclotron: begun as a personal project by two undergraduates in 1995, it became the centerpiece of the Rutgers modern physics teaching lab from 2001, reliably producing 800 keV proton beams by 2006 and, after a PIG ion source upgrade in 2012, tens of microamperes over 30-hour runs. Nineteen undergraduates gained hands-on accelerator experience on the machine, several going on to accelerator-physics careers. In 2016 it moved to the University of Maryland, where it anchors a capstone design class.

    Koeth cyclotron siteKoeth group (University of Maryland)Terp Magazine: Beam Team

  9. Knox College Cyclotron

    Jeff Smith, undergraduate at Knox College, Illinois c. 1999–2001

    outcome unknown USA

    A fixed-frequency cyclotron built as an honors senior thesis in physics, completed in 2001 with assistance from Fermilab cyclotron builder Chris Olsen after the builder encountered cyclotrons at a Fermilab public lecture. The builder went on to accelerator physics at Cornell and SLAC; the machine itself remains in the basement of Knox College, and no documentation of a demonstrated beam has been published.

    Symmetry: The do-it-yourself cyclotron (2010)Builder profile (SETI Institute)

  10. Houghton College Cyclotron

    Mark Yuly and successive undergraduate students, Houghton College, New York 2003–present

    beam demonstrated USA

    Chamber 170 mm (6.7 in) inner-diameter aluminum chamber
    Field ≈1.1 T (11 kG)
    Particle protons, deuterons, helium ions
    Energy design energies of tens to hundreds of keV; picoampere-scale internal beams measured
    Vacuum diffusion-pumped high-vacuum system

    A deliberately small cyclotron developed as a continuing undergraduate research program, with each student generation documenting improvements in theses and conference talks since 2003. The machine has accelerated ions — beam-current-versus-radius measurements at the helium resonance and at least one proton run are documented — though hardware failures have repeatedly interrupted operation. It hosted the first amateur cyclotron conference in 2010 and remains a teaching and research tool.

    Houghton College cyclotron papers (institutional repository)Physics Procedia: The Houghton College Cyclotron (2015)

  11. MIT 2 MeV Cyclotron Project

    Leslie Dewan, undergraduate at MIT c. 2006–2007

    outcome unknown USA

    Particle protons
    Energy 2 MeV (design)

    An undergraduate thesis project documenting the design and construction of a cyclotron intended to accelerate protons to 2 MeV for low-energy beam experiments in MIT's nuclear engineering department. The thesis and two videos are the surviving public record; no demonstrated beam is documented, and the project appears not to have been completed.

    MIT thesis (DSpace@MIT)Project video (YouTube)Project video, part 2 (YouTube)

  12. Cyclotron Kids 2 MeV Cyclotron

    Heidi Baumgartner and Peter Heuer (high-school students), with German Diagama; built at Jefferson Lab c. 2008–2013

    stalled USA

    Dee diameter 305 mm (12 in) single dee with grounded dummy dee
    Field 1.6 T (16 kG)
    RF frequency 24 MHz, 3 kW tube amplifier
    Particle protons
    Energy 2 MeV (design)
    Vacuum 10⁻⁷ torr (design)

    Two high-school students designed a 2 MeV proton cyclotron and, after a funding email reached the associate director of Jefferson Lab, were invited to build it at the national lab over several summers. All components — a 1.6 T H-magnet, welded stainless chamber, 24 MHz RF system, and thermionic ion source — were completed, but lab safety rules for minors prevented power testing, and no beam was ever run. The machine was transferred to Old Dominion University to await further student work; both builders went on to physics careers.

    The Cyclotron Kids project siteCyclotrons2013 paper (WE1PB05)

  13. COLUMBUS School Cyclotron

    Ch. Wolf, M. Frank, E. Held and students, Gymnasium Ernestinum, Coburg c. 2010–2016

    beam demonstrated Germany 24–48 keV

    Pole diameter 150 mm (6 in), Bruker BE-15 laboratory magnet
    Field 0.38 T (3.8 kG) operating; up to 0.7 T available
    RF frequency 5.63 MHz, 2–3 kV dee voltage
    Particle protons
    Energy 24–48 keV design; no extraction, by design, so no radiation escapes
    Vacuum 10⁻⁵ mbar (10⁻⁴ mbar with hydrogen flowing)

    A teaching cyclotron built at a German Gymnasium expressly so that students could see and operate a real accelerator, using standard components and donated hardware including a Jülich laboratory magnet and an industrially fabricated chamber. The design keeps final energy low enough that no harmful radiation leaves the chamber, and the machine registered its first proton beam in April 2014, with continued improvements in following years. It was presented at the Cyclotrons 2013 conference.

    Cyclotrons2013 paper (WE1PB03)Press report on first beam and later upgrades (2016)

  14. University of Maryland 19-Inch Cyclotron

    Undergraduate design classes led by Timothy Koeth, University of Maryland c. 2016–present

    in progress USA

    Pole diameter 483 mm (19 in), restored historic magnet
    Particle protons (planned)

    A successor machine under construction by successive undergraduate cohorts at the University of Maryland, built around a restored 19-inch magnet alongside the relocated Rutgers 12-inch cyclotron. Unlike the 12-inch machine, whose beam stays inside the chamber, the 19-inch design is intended to extract beam for experiments; on completion it would be the largest cyclotron built by undergraduates.

    Terp Magazine: Beam TeamKoeth cyclotron site: 19-inch magnet restoration

  15. Mullins Cyclotron

    Simon and Chris Mullins (father and son, home-built) 2017–2019

    beam demonstrated USA ≈164 keV

    Field 582 mT (5.82 kG)
    RF frequency 8.87 MHz
    Particle protons
    Energy ≈164 keV demonstrated

    A father-and-son garage build documented on a dedicated project site, carried from magnet design through working machine between 2017 and 2019. Operating at 582 mT with an 8.87 MHz RF system, it demonstrated acceleration of protons to approximately 164 keV. The build log covers the magnet, vacuum system, RF chain, and beam measurements.

    Project build log

  16. The Cyclotron Project

    Reed Michael Upson and Ray Anchordoquy (backyard workshop build) 2018–present

    in progress USA

    Dee diameter 356 mm (14 in)
    Field ≈0.3 T (3 kG) median-plane
    Particle protons
    Energy 60 keV target (revised down from 1.1 MeV over incidental-radiation concerns)
    Vacuum 10⁻⁵ torr target

    A two-person build housed in a purpose-built, Faraday-caged garden shed, under way since 2018 and documented on a project site. The original 1.1 MeV goal was deliberately reduced to about 60 keV to avoid incidental radiation hazards. As of the site's last update in late 2024, subsystems including vacuum and the ion source were being validated individually and no beam had yet been produced.

    Project site

  17. Dawson College Mini Cyclotron (EMC²)

    Student-led “Engineering a Mini Cyclotron Crew”, Dawson College, Montreal 2020s

    in progress Canada

    A student-led initiative at a Montreal CEGEP with the stated goal of constructing a compact cyclotron as a hands-on learning project, with leadership rotating to new students each fall. The college foundation page describes the program but publishes no specifications or construction milestones, so the project may still be at the design stage.

    Dawson College Foundation project page

Know of a documented build that is missing here? Corrections and additions with sources are welcome via the contact address on the About page.