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

Mon Mar 6 12:15:01 CST 2017

If we are talking about measurements applicable to the personnel protection, there is no need to use exposure units with following calculations. Instead, Ambient Dose Equivalent  (H*(10)) could (should?) be used. It is measured in Sv, and many monitoring equipment manufacturers now give you an option of scales in exposure or H*(10) units. There are many publications and articles on this toping, probably ICRU 1993 would be a best source, but here's also a couple:

https://hps.org/publicinformation/ate/q8949.html

http://www.nucleonica.net/wiki/index.php?title=Ambient_dose_equivalent_H*(10)

But, of course, until regulations adopt these changes in US, it'd be very difficult to use H*(10) calibrated monitors here. 

Konstantin Povod, CHP, RRPT
RSO, LSO Clemson University

-----Original Message-----
From: radsafe-bounces at health.phys.iit.edu [mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Ted de Castro
Sent: Monday, March 6, 2017 11:54
To: The International Radiation Protection (Health Physics) Mailing List <radsafe at health.phys.iit.edu>
Subject: Re: [ RadSafe ] Adopting the International System of Units for Radiation Measurements in the United States: Proceedings of a Workshop

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_96101d
>> e015- b2788914c1-102196093&mc_cid=b2788914c1&mc_eid=3ee8f719d6>
>>
>>
>> ---
>> Cary Renquist
>> cary.renquist at ezag.com
>>
>> _______________________________________________
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>

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