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Cyclotron regulation in Maine
Verified August 2026
One entry from the 51-jurisdiction survey, read against a small, fully enclosed, sub-MeV machine whose beam terminates inside its own vacuum chamber.
- Small machine vs. definition
- Arguably outside — Arguably outside the accelerator definition
A reading of the definitional text, not a determination: the machine is arguably outside the accelerator definition, and classification remains the state agency’s call.
- How Maine defines “particle accelerator”
- CRCPD-model definition (extraction clause + “usually >1 MeV”)
- Governing citation
- 10-144 C.M.R. ch. 220, Part A, § A.2
- Register / license
- License (accelerators)
- Incidental-radiation exemption
- Part F, § F.3.D(1) — “for other purposes” lead-in
- Notes (as verified August 2026)
- CRCPD-model definition, but accelerators that meet it are licensed, and the registration part is written around X-ray machines — leaving low-energy particle machines in a residual gap.
What to do
Identify the state radiation-control program before the machine is first energized. Ask the program in writing how it classifies the machine before purchasing or building one, rather than relying on a private reading of the definition. Document the machine’s maximum energy and the fact that its beam is internal to the vacuum chamber — that record is what any classification, exemption argument, or registration review turns on.
This is information, not legal advice. Everything on this page was verified against primary sources (statutes, administrative codes, agency publications) as of August 2026. Regulatory text moves — several states recodified or rewrote their radiation rules in 2023–2026 alone — so anything consequential should be re-checked against the current text of the cited provision, and questions about a specific machine belong to the state radiation-control program or qualified counsel.
See the legal overview for the federal layer and how the incidental-radiation exemption is read, and the full 51-jurisdiction table and map for every other state.