"X-Ray Machine" and "Accelerator" Definitions

[David W Lee <lee_david_w@lanl.gov>]

RADSAFERS:

        This message is directed primarily to any RADSAFER who may be associated with any State Office of Radiological Control. 

        While federal regulations exist through the Food and Drug Administration (FDA) (21 CFR Subchapter J) specifying standards that various manufacturers of electronic products that produce ionizing or nonionizing radiation must meet, the actual regulation of "x-ray machines" and "accelerators" is largely the responsibility of the various States.  Also, in that the Nuclear Regulatory Commission (NRC) is legally authorized through the Atomic Energy Act of 1954 (as amended) to regulate only "source," "byproduct," and "special nuclear" materials, many NRC "Agreement" States have succeeded in getting their respective State legislatures to authorize the State to regulate not only "x-ray machines," but also accelerator-produced radioactive materials and naturally occurring radioactive materials (NORM) that the NRC otherwise cannot regulate.

        In that "x-ray machines" accelerate charged particles (electrons) into an x-ray production target, from a strictly physics standpoint, it is true that "x-ray machines" are a subset of the larger universe of "accelerators."  Many organizations, however, (NCRP, ICRP, Agreement States, American National Standards Institute (ANSI), Conference of Radiation Control Program Directors (CRCPD)) have, nevertheless, chosen to differentiate an "x-ray machine" from an "accelerator" by formulating separate definitions for each of these terms.  Separating "x-ray machines" out from and apart from the larger "accelerator" universe apparently has been done under the presumption that "x-ray machines," apart from other "accelerators," ought to be regulated a bit differently from the remaining "accelerator" universe, otherwise there would appear to be no good reason to separately define these two terms.  While I do not necessarily agree that "x-ray machines" need to be defined separately from "accelerators," I am merely trying to describe what historically appears to have been done.

        Presently both ANSI and the NCRP (http://www.ncrp.com/review.html) appear to want to continue the historical trend of differentiating an "x-ray machine" from an "accelerator" by continuing to formulate separate ANSI standards (N43.1 and N43.3) and NCRP reports (NCRP 35, 49, 72, 79, 102, etc) pertaining to "x-ray machines" separate from "accelerators."

        Some of us here at Los Alamos National Laboratory have expended considerable effort analyzing the questions "what is an x-ray machine"? versus "what is an "accelerator"? in an attempt to formulate hopefully better "x-ray machine" and "accelerator" definitions that do not semantically overlap each other.  Also, we have formulated a new, single definition that does away with the former "x-ray machine" vs. "accelerator" dichotomy.  We, however, do not claim to have a corner on the market as far as our understanding of the many "x-ray machine" vs. "accelerator" definitions that already exist.  In order to further refine our understanding of what other States/countries define as an "x-ray machine" vs. and "accelerator," I respectfully ask any RADSAFER to provide me his/her State's official definition of an "x-ray machine" and an "accelerator."  In return for your efforts in this regard, I promise that I will place you on the "Distribution" list to receive an electronic copy of our "x-ray machine" vs. "accelerator" definitions analysis report which will be transmitted to your e-mail address as a ".pdf" file.  I would be particularly interested in being informed what the now federal country of Canada uses as definitions of an "x-ray machine" vs. and "accelerator."

        I leave it to your judgment as to whether you consider this "x-ray machine" vs. "accelerator" definitional issue to be of sufficiently wide interest to post to the RADSAFE net or to send to me at my personal e-mail address below.  

        Thank-you, best regards  David
        

        

        

DAVID W. LEE
Los Alamos National Laboratory
Radiation Protection Services, ESH-12
X-Ray/Source Control Team Leader
PO Box 1663, MS K483
Los Alamos, NM  87545
PH:   (505) 667-8085
FAX:  (505) 667-9726
lee_david_w@lanl.gov