[ RadSafe ] Adopting the International System of Units for Radiation Measurements in the United States: Proceedings of a Workshop

Jason Meade meadeja at vcu.edu
Mon Mar 6 11:10:04 CST 2017


"Did the workshop have anything to say about the rampant misuse of units
afforded us by SI?"

Sort of, briefly, and quite indirectly.

But it was more covered under the confusion and misdirection in journalism,
in the public arena, and in emergency response communication issues due to
mix and match problems of dual system usage, an not really covered as a
separate issue.

On Mon, Mar 6, 2017 at 11:53 AM, Ted de Castro <tdc at xrayted.com> wrote:

> Did the workshop have anything to say about the rampant misuse of units
> afforded us by SI?
>
> Thanks to an incredibly cumbersome EXPOSURE unit - regulatory exposure
> limits are now being expressed in DOSE units without specifying - dose to
> what.
>
> Back in the back old days when we where just too stupid to know any better
> these things were expressed in exposure units.  When a DOSE unit was
> expressed - rad - it was expressed as rad in xxxx. And was seldom measured
> but usually calculated.
>
> So I recently encountered a quasi regulatory document called SEMI 2 which
> has among other things:
>
> "Direct doserate measurement with an Ion Chamber {or equivalent) calibrated
> to +/- 10% of true doserate at the surface of the equipment (or at the
> closest
> approach) in all areas where the operator may have access with the ionizing
> radiation source active.*"
>
> *Sorry - wrong!  An ion chamber is an exposure instrument NOT dose rate -
> and this is for analytical x-ray for which the spectrum from one end to the
> other varies considerably and the exposure to dose ratio is spectrum
> dependent and will vary more than the requisite 10% from one end to the
> other.  Let along the body part to which their dose limits apply is not
> specified.  (they give the limits in Sv) I maintain there is in fact no
> survey instrument that can measure this!
>
> So - with their use of SI and misuse of type of unit we are confronted
> with a published imperative which is clearly impossible to comply with.
>
> So - what did the workshop have to say about ion chambers with Sv marked
> on the meter faces?
> *
>
> ***
> On 3/3/2017 5:51 AM, Jason Meade wrote:
>
>> It was a great workshop and well worth my time, but after it was done, I'm
>> pretty sure it will be done again with almost an identical agenda in 10
>> years time.
>>
>> Entirely too much "but this is the way we've always done it" and "it would
>> be too hard" type talking among those who've always been doing the work
>> and
>> who are largely in charge for any type of shift in thinking, despite the
>> fact that the majority of the scientific and academic portions of our
>> education system have already made the change.
>>
>> On Thu, Mar 2, 2017 at 11:38 AM, Cary Renquist <cary.renquist at ezag.com>
>> wrote:
>>
>>  From the National Academies Press.
>>> One can always download the PDF version for free (might require an
>>> account)
>>>
>>> Adopting the International System of Units for Radiation Measurements in
>>> the United States: Proceedings of a Workshop
>>>
>>> Most countries in the world use the SI (Système International, also known
>>> as the metric system) units for radiation measurements in commercial and
>>> technical activities. The United States, in contrast, uses a mix of SI
>>> and
>>> conventional units for radiation measurements, despite 30-year-old
>>> national
>>> and international recommendations to exclusively use SI. Radiation
>>> professionals in the United States are faced with the need to understand
>>> both systems and make conversions between the two.
>>> Short link
>>> http://bit.ly/2mPP5bQ
>>>
>>> Adopting the International System of Units for Radiation Measurements in
>>> the United States: Proceedings of a Workshop | The National Academies
>>> Press
>>> <https://www.nap.edu/catalog/24645/adopting-the-
>>> international-system-of-units-for-radiation-measurements-in-
>>> the-united-states?utm_source=NASEM+News+and+Publications&
>>> utm_campaign=b2788914c1-Final_Book_2017_03_02_24645&utm_
>>> medium=email&utm_term=0_96101de015-b2788914c1-102196093&
>>> goal=0_96101de015-
>>> b2788914c1-102196093&mc_cid=b2788914c1&mc_eid=3ee8f719d6>
>>>
>>>
>>> ---
>>> Cary Renquist
>>> cary.renquist at ezag.com
>>>
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>>
>>
>
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-- 
Thanks,
Jason A Meade, AS, BS, MHSA, RRPT, RT(T)
Senior Radiation Safety Specialist
Virginia Commonwealth University


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"A society grows great
when old men plant trees
whose shade they know
they shall never sit in."
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Bad is passing test depth at 80 feet per second with a thirty degree down
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