Construction Classics

The Argonne 60-Inch Cyclotron

Why this document can be hosted

ANL-5907 is labeled on its own title page as an “AEC Research and Development Report,” produced by Argonne National Laboratory under AEC contract W-31-109-eng-38; AEC-issued contractor reports are treated as US Government works, which carry no copyright. Pre-1978 distribution without a copyright notice stands as an independent public-domain basis. Verified against the title page, distribution markings, and the OSTI record; determination made August 2026.

Reading guide

Forty pages, no theory, every subsystem reduced to numbers. The Argonne 60-inch was bought from Collins Radio on a fixed-price performance contract, and this report reads like the acceptance record it grew out of — the deflected-beam specifications the machine had to meet are printed on p. 3. For a builder it is the collection’s best answer to the question “what does a finished, reliable machine actually measure?” Page references are the report’s printed numbers; the hosted PDF runs two pages ahead.

The description chapter walks the systems in order. Cooling (p. 4): a 1000 kW plant against a 300 kW normal load, demineralized water held at or below 10 micromho, and dee water stable to 1°F. Vacuum (pp. 4–8) contains the report’s two best fabrication passages — the dee assembly mounts on a motor-driven carriage running on a grooved rail so the whole RF system rolls out of the chamber for service (p. 4), and the welded vacuum-box specification demands continuous seam welds on the atmosphere side only, with internal braces stagger-welded to keep virtual leaks to a minimum (p. 5). The magnet section (pp. 8–10) is a page of tolerances worth memorizing as ratios: gap variation under 0.005 inch at any radius, Rose-ring shims 1/4 inch thick by 2 inches wide at 26–30 inch radius, azimuthal field variation under 1 part in 3000, and a magnetic median plane within 0.030 inch of the geometric one (p. 10).

The arc source (pp. 10–11) is consumables planning in three paragraphs: tantalum hairpin filament in a graphite chimney, 50–120 V at 6–8 A on about 0.1 cc/min of gas, 25–30 hour filament life, and a mechanical design that gets a filament change done in fifteen minutes. RF (pp. 11–14) gives the full electrical picture of an unbiased twin-dee system at 240 kV dee-to-dee for 105 kW of plate input; the deflector (pp. 14–16) runs at 75 kV from a 150 kV supply — two-to-one electrical headroom — and delivers 25–40% acceptance efficiency, an honest number for a mature machine. Operation and beam characteristics (pp. 16–25) include measured deflected-beam profiles (Figs. 10–12, p. 19). The building chapter (pp. 26–32) shows the floor plan driven by the dee withdrawal path. Appendix I (pp. 34–36) is a one-stop specification summary; Appendix II (pp. 37–39) names the suppliers and fabricators of every major component — the only such list in the collection.

What scales down: the tolerance ratios, the weld and water-quality discipline, the headroom habits, and the maintainability thinking. What does not: 22-inch pole gaps, 150 kV deflector supplies, and a 265-ton magnet. The hosted copy is an OSTI scan whose text layer is searchable but carries spaced-letter OCR artifacts; a cleaner searchable copy is planned.

Design rules extracted from this document

8 Design Guide rules cite ANL-5907. Representative examples:

• dg-029 — hold pole-gap parallelism to better than 0.005 in
• dg-030 — Rose-ring shims to correct edge-field falloff
• dg-461 — weld discipline against virtual leaks
• dg-186 — size the cooling plant with ~3× margin
• dg-492 — design for maintenance access from day one

Used by the magnet design, ion sources, and beam extraction deep dives.