The Rutgers/Maryland 12-inch corpus
The Rutgers 12-inch cyclotron — begun in a New Jersey basement in 1995 by two undergraduates, a Rutgers teaching accelerator from 2001, and since 2016 the centerpiece of a University of Maryland capstone program — is the best-documented amateur-origin cyclotron in this site's census. Its builders wrote the machine up continuously for two decades: subsystem memos during construction, conference papers once it matured, and neutron-physics reports after the move to Maryland. This page is a reading guide to that record: 17 documents, in the order the machine earned them.
Every link below points at the authors' own hosted copies, on the NPL 12-Inch Cyclotron Papers page. That collection is the canonical home of these documents, and they are its authors' copyright, so this site links rather than hosts. Where the Internet Archive holds a verified snapshot, an “archived” badge follows the link, so the record outlives any one server. For the machine itself, see the census entries for the 9-inch prototype, the 12-inch, and the Maryland 19-inch successor, the program history, and the builders' sites: koethcyclotron.org (subsystem documentation), the project history at timkoeth.com, and the Cyclotrons! video series.
Why this corpus matters to a builder: it is the one sustained record of a small machine written while being figured out, at amateur scale, in memo form — the measurements, the models that did and did not match them, and the high-voltage problems reported as problems. 16 of the documents have been mined into the Design Guide (267 rules cite them, each with a page-referenced verbatim quote), and the German COLUMBUS school cyclotron's builders write that their ion source “was built after the pattern of Tim Koeth”, citing Part I of the ion-source studies (dg-1524). It is the clearest documented case of this record teaching a machine into existence elsewhere.
Build and commissioning memos (2005–2015)
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The 9-Inch Cyclotron construction writeup (with drawings)
An 18-page scanned writeup of the original 9-inch-magnet prototype, drawings included — the same chamber later run between 12-inch poles. One of the most reproducible small-cyclotron documents on the open web.
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Report on the 12-Inch Cyclotron Magnet Study: Measurements, Modeling, and Future Plans
Field measurements and modeling of the 12-inch magnet, with the plans that shaped the pole-tip work that followed.
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Theoretical Calculations and Measurements of the Dee Voltage in the Rutgers 12-Inch Cyclotron
Dee capacitance estimated by summing parallel-plate sections, then dee voltage measured three independent ways. The memo behind this site's dee-voltage design rules.
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Rutgers 12-Inch Cyclotron Ion Source Studies: Part I archived Aug 2026
The filament ion source and first central-orbit studies — the source pattern the German COLUMBUS school cyclotron later adopted by name.
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Observation of Betatron Motion in the Rutgers 12-Inch Cyclotron
First observed betatron motion in the machine, found consistent with radially increasing proton energy.
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Rutgers 12-Inch Cyclotron Ion Source Studies: Part II (Ion Source Simulations and Measurements)
SIMION 3-D particle tracking brought to bear on the ion source, with the measurements that checked it.
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Rutgers 12-Inch Cyclotron Electrostatic Deflector
The electrostatic deflection channel built to verify final beam energy directly — including the high-voltage problems along the way. Companion to the 2010 conference slides in the library.
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Weak-focusing versus azimuthally-varying-field pole tips compared on one machine — the interchangeable-pole-tip experiment that few laboratories of any size can run.
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Field Mapping in Cyclotron Magnets archived Aug 2026
2-D field mapping of four interchangeable pole-tip sets, written explicitly so others can set up the same measurement.
Conference papers (2013–2016)
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The Rutgers Cyclotron: Placing Student's Careers on Target
The program's outcomes paper, written by its students: what building and running the machine did for the careers of the people who did it.
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A Novel Optical Method for Measuring Beam Phase and Width in the Rutgers 12-Inch Cyclotron
Beam phase and width measured optically — bunch structure resolved within a single RF cycle on a 12-inch machine.
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Rutgers 12-Inch Cyclotron: Dedicated to Training Through Research and Development
The machine-overview paper the census entry cites: history, subsystems, and the training-through-R&D model.
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Beam Physics Demonstrations with the Rutgers 12-Inch Cyclotron
The beam-physics teaching repertoire: focusing, betatron motion, resonances, and diagnostics as classroom demonstrations.
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Undergraduate Education with the Rutgers 12-Inch Cyclotron archived Aug 2026
The education-program paper, also available by DOI via its library entry.
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Tunes measured from betatron motion across pole configurations — written when the machine anchored the two-week USPAS cyclotron course.
The neutron program (2017–2020)
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Neutron Production with a 12-Inch Cyclotron
D–D fusion neutrons from a deuterium-loaded titanium target: RF halved for deuterons, the radiological controls that made it permissible, and the calibration against a NIST-traceable ²⁵²Cf source.
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Measurement of Neutron Diffusion Time from Fast Pulsed Systems
The cyclotron pulsed down to a 10 µs beam-on-target window to time neutron diffusion in a polyethylene moderator — the fundamental-physics measurement the census entry describes.
How this page is preserved
The documents stay where their authors put them; this site records each link's Internet Archive snapshot and shows it beside the live link once verified, following the same preservation practice as the census and library citations. If a link above has gone dark and shows no archived badge yet, the snapshot usually exists — check the URL directly at web.archive.org, and report the dead link so the page can be updated.