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Re: Badge Reading Differences
On 22 Jul 2004 at 14:40, R. J. Gunter wrote:
>
> Mr Garrett,
>
> The difference is not surprising. You might ask to film dosimeter
> provider (I assume this one read higher) to analyze the response
> assuming the exposure was from X-rays only (they have this option
> available if you ask for given wearers). This will likely reduce the
> dose considerably. In my consultancy I recommend appropriate
> dosimeters for clients based on their use. Film is an excellent
> dosimeter if you know exactly what the film was exposed to and use
> that assumption when you read it. More likely than not, they just ran
> the film badge with no assumptions. Angular response exposes the area
> under the filter making the effective energy seem higher. This makes
> the overall dose higher by about the factor you mention below.
Hi Rob,
You have been away from us fore quite some time. Your information
regarding our film algorithm needs "quite a bit" of tweaking.
1. Our 5 element film dosimeter is treated like a TLD.
2. Our algorithm was based on thousands of irradiations to all of the
72 beam codes, NIST, ISO and Narrow, including all of the required
angles, +/- 60 degrees, and in the H and V orientation.
3. The algorithm has finger prints for each of these combinations.
4. In addition, we read the film using a laser and CCD camera, which
captures the entire image, not just the filtered areas, and,
digitizes the entire output, for detailed analysis.
5. The algorithm treats the film 5 elements like a TLD, and, the
finger-print, similar to a DNA finger-print, identifies not only the
type of radiation, energy, etc., but also the most likely incident
angle. The algorithm even provides the assumed mixture, percent and
for each component.
As you can see, our algorithm is quite sophisticated, and, we passed
the entire ANSI N13.11-2001 Performance Test Standard, including
excellent response in Cat. IIA. Our film performance is on par, if
not better than many TLD systems out there performing NVLAP badging.
Also, please note that the film was NOT the dosimeter in question.
The dose we reported was consistent with what the Radiologists
expected to see, base don historical data.
We can talk some more and bring you up-to-date :)
Sandy
------------------------------------
Sandy Perle
Sr. Vice President, Technical Operations
Global Dosimetry Solutions, Inc.
3300 Hyland Avenue
Costa Mesa, CA 92626
Tel:(714) 545-0100 / (800) 548-5100 Extension 2306
Fax:(714) 668-3149
E-Mail: sperle@dosimetry.com
E-Mail: sandyfl@earthlink.net
Personal Website: http://sandy-travels.com/
Global Dosimetry Website: http://www.dosimetry.com/
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