[ RadSafe ] Re: attn. Landauer Customers

[Dale Boyce]

Hi Sandy,

Of course I understand that geometry is part of it, but take a box with very 
small dimensions, and a radioactive shipment with dose rates high enough to 
expose the badges.  The radioactive shipment will always have dimensions 
large compared to the  small box. Even if the badge box was sitting on the 
shipment the dose rate across the small box should not vary much.

However, the main point is how can one make a reasonable correction to the 
report?  Assume a facility where the expected dose is next to nothing, but 
that some people really do get exposures.  It is awfully hard to justify 
either zeroing out the people that are likely to have received the dose, or 
to believe the ones that shouldn't have had the exposure.  Something that an 
automated process at the vendor would have more trouble dealing with 
(possibly) than the vendor.

Probably the best solution if this occurs is to treat all the badges as 
damaged/lost and to replace them with estimated doses, except in the cases 
where the badges receive dose significantly higher than the typical "in 
transit" exposure.

Dale
----- Original Message ----- 
From: "Sandy Perle" <sandyfl at earthlink.net>
To: "Dale Boyce" <daleboyce at charter.net>
Cc: <radsafe at radlab.nl>
Sent: Wednesday, August 24, 2005 6:21 PM
Subject: Re: [ RadSafe ] Re: attn. Landauer Customers


> Hi Dale,
>
> This all has to do with source geometry, is it a point source, several 
> point sources, or more like a line source. location of source(s), 
> distance, angle, etc. This is not an unusual observation.
>
> Regards,
>
> Sandy
>
>
> On 24 Aug 2005 at 18:01, Dale Boyce wrote:
>
>> John's point is definitely a real one. While I have personally seen
>> doses as high as 300 mrem from intransit, I have seen a report come
>> back for a couple of thousand badges, several hundred of which had
>> exposures reported between 10 and 50 mrem with most in the 20 to 30
>> mrem category.
>>
>> Since these films were all shipped in the same box, one wonders why
>> the spread in reported exposure. Even though it is a lot of badges
>> when shipped as the film only the box is pretty small.
>>
>> Also, what correction could be applied in such a case if the control
>> showed 0, 10, 20, 30, 40, or 50 mrem?
>>
>> I guess one solution is to not use carriers that also handle isotopes.
>> The second best would be to not use the same carrier(s) that deliver
>> isotopes to your facility, since the most probable place for the
>> badges to be placed near a source in transit is during final delivery.
>> However, in the case mentioned different carriers were used, but the
>> one delivering the badges also does or at least did transport RAM.
>>
>> Dale
>>
>>
>> ----- Original Message ----- 
>> From: "Wright, Will (DHS-PSB)" <WWright2 at dhs.ca.gov>
>> To: "Flood, John" <FloodJR at nv.doe.gov>; <sandyfl at earthlink.net>;
>> <jblute at NITON.com>; <radsafe at radlab.nl>; "Neill Stanford"
>> <stanford at stanforddosimetry.com> Sent: Wednesday, August 24, 2005 5:03
>> PM Subject: RE: [ RadSafe ] Re: attn. Landauer Customers
>>
>>
>> i believe i deleted the initial strings, could someone briefly
>> describe the issue or was this simply a discussion about the
>> inconvenience of maintaining a control. controls are critical as
>> indicated in all objective science endeavors/ bench top science as
>> well as others will teach this the hard way.
>>
>> -----Original Message-----
>> From: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl]On
>> Behalf Of Flood, John Sent: Wednesday, August 24, 2005 2:52 PM To:
>> 'sandyfl at earthlink.net'; jblute at NITON.com; radsafe at radlab.nl; Neill
>> Stanford Subject: RE: [ RadSafe ] Re: attn. Landauer Customers
>>
>>
>> Perhaps I missed a post on this subject, but the discussion seems to
>> be overlooking the in-transit exposure that a control dosimeter also
>> monitors. There is no doubt that accurate background subtraction is
>> important to low dose measurements, but the absence of background
>> measurements can be a horrifying experience if every dosimeter in the
>> shipment to the processor shows a few hundred mrem from irradiation
>> in-transit.  This is a very real, modern problem - if your dosimeters
>> sit next to some clinic's radionuclide shipment on the truck or in the
>> warehouse, expect to see 50-300 mrem on every dosimeter (how would I
>> know this?).  Without control dosimeters, life certainly gets more
>> complicated.
>>
>> Bob Flood
>> Nevada Test Site
>
> ----------------------------------------------------------------
> Sandy Perle
> Senior Vice President, Technical Operations
> Global Dosimetry Solutions, Inc.
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>
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