Construction Classics

Cyclotrons and High-Energy Accelerators — 1958

Why this document can be hosted

ORNL-2644 is an Oak Ridge National Laboratory report produced by Union Carbide for the AEC under contract W-7405-eng-26 — both statements are printed on its title page. AEC-issued contractor reports are treated as US Government works, which carry no copyright; pre-1978 distribution without notice is an independent public-domain basis, the same rationale as the hosted ORNL-1196 and ORNL-2648. Verified against the title page and the OSTI record; determination made August 2026.

How to use this compendium

This is not a report to read; it is a database to query — 140 accelerators worldwide, verified questionnaire data for 108 of them, collected by ORNL in mid-1958 and printed as standardized data sheets. For anyone trying to place a design in context, it answers one question no single machine report can: what did everyone else choose? Page references are the report’s printed numbers; the hosted PDF runs seven pages ahead.

Entry is through the General Directory (pp. 3–14), organized by country, then institution: each line gives machine type, pole diameter, energy, particle, status, and the page of its data sheet. The sheets themselves are grouped by machine class — fixed-frequency cyclotrons from p. 15, frequency-modulated machines from p. 171, synchrotrons and linacs from p. 209 — and every machine gets the same two-page form. The first page is design data: magnet (pole-tip and core diameter, gap, peak field, iron weight, winding, cooling), RF (dees, frequency, dee voltage, oscillator input), history and cost. The second is measured performance: energy, frequency, field, dee-to-dee kilovolts, stable and peak beam currents internal and external, an “unusual features” note, and — the quiet treasure — the published articles describing the machine, which make each sheet a doorway into that machine’s literature.

Three worked uses. First, sizing by precedent: to see every machine near a given pole diameter, sweep the directory’s size column — the fixed-frequency section spans Melbourne’s 39-cm variable-energy machine (p. 21) to the largest classical cyclotrons, so a small-machine builder can find the cluster of sub-half-meter designs and read exactly what fields, dee voltages, and beam currents they achieved. Second, sanity bands: collecting dee-to-dee voltage against energy across the fixed-frequency sheets gives an empirical envelope for judging whether a proposed RF budget is ambitious or routine. Third, survey statistics: the summary table (p. 1) counts the 1958 fleet — 76 fixed-frequency cyclotrons, 18 FM machines built, 50 machines then under construction or design — the baseline snapshot of the field at the AVF transition. Howard’s foreword states the data discipline: questionnaire returns were edited only for terminology, and unverified entries are flagged as such.

The hosted copy is an OSTI scan with a text layer that is searchable but noisy on the tabular pages — numbers OCR badly — so use the text layer to find a machine and read the values from the page image.

Design rules extracted from this document

13 Design Guide rules cite ORNL-2644 — census-population envelopes rather than single-machine numbers: what field, dee voltage, RF power, geometry, and budget the 1958 fleet of small machines actually converged on. A pass feeding the world cyclotron database with historical entries remains queued. Representative examples:

Used by the beam dynamics deep dive and the industry reference.

• dg-697 — every working small classical cyclotron ran 12.5–18.5 kG center field
• dg-700 — magnet iron grows roughly with the cube of pole diameter
• dg-701 — census geometry template: gap, dee aperture, and dee diameter proportions
• dg-702 — shim for only 2–4% total field drop-off, center to maximum beam radius
• dg-709 — whole working cyclotrons were built for $5k–$110k in about two years