RE: Dosimeters and airport security - Relative Response of dosimeters[Scanned]

["Dr Christoph Hofmeyr" <chofmeyr@nnr.co.za>]

Title: Message

Radsafers, 

This is probably more true of neutrons than of low-LET radiations (and therefore also of mixed fields). I am aware that some facilities exchange dosemeters before the wearer enters a mixed field (and change back upon leaving) and the doses are added administratively.  With guests, this strategy could be complicated by the question of who is the responsible party.

What about dosimetry sevice providers that serve many different facilities.  Possibly one could ask Sandy Perle (ICN) and/or someone from Landauer to comment.  IMHO the problem is due to the limitations of existing dosemeters.

Chris  Hofmeyr

chofmeyr@nnr.co.za

-----Original Message-----
From: Rob Gunter [mailto:rgunter@SEC-TN.COM]
Sent: 14 January 2003 03:41
To: Radsafe
Subject: RE: Dosimeters and airport security - Relative Response of dosimeters[Scanned]

Well said Neil,

 

This is something that most HPs are unaware of.  The relative response of their dosimeter to different radiation fields.  Your dosimeter is not likely to respond the same as the one at a facility you visit, even if it is an identical dosimeter model.  Dosimeters are not one size fits all.

 

Rob

 

Robert J. Gunter, CHP
East Tennessee Technology Park
Operations Support Manager
Safety and Ecology Corporation
Bldg 1020, Rm 18
Oak Ridge, TN 37830
Ph:  (865) 241-9748
Cell: (865) 556-4380
Pager:  (865) 873-0078

-snip-

 

 IMNSHO, commercial external dosimetry services have not evolved to the point where a single dosimeter design/algorithm is applicable to all radiation environments with sufficient accuracy.  Different designs have different strengths, and even within their area of strength, can be improved upon with knowledge of the anticipated field conditions.

 

Neill

----------------------------
Neill Stanford, CHP
Stanford Dosimetry
www.stanforddosimetry.com
stanford@stanforddosimetry.com
360 293 9334
---------------------------

-----Original Message-----
From: owner-radsafe@list.vanderbilt.edu [mailto:owner-radsafe@list.vanderbilt.edu] On Behalf Of JGinniver@AOL.COM
Sent: Friday, January 10, 2003 5:50 PM
To: radsafe@list.vanderbilt.edu
Subject: Re: Dosimeters and airport security

As I read the responses from my colleagues in the US I am struck by just how fundamental the differences can be between countries.  In my response earlier I indicated that I would recommend the use of 'double badges'.  The main reason for this is that in the UK it is the responsibility of the employer of the 'radiation worker' to measure and record his or her dose.  It is interesting for me to note therefore that in the US the responsibility lies with the site/facility to measure the dose of those persons working in their plant/facility with radiation.

This is why in the UK your legal dosimeter is the one issued by YOUR employer.  One of the reasons for issuing a second dosimeter to personnel from other employers is to ensure that the site/facility can monitor dose uptake for all persons working on the site and to be able to accurately assess the sites collective dose during each reporting period.  I do wonder (like others on the list) how accurate an individuals dose assessment can be if the work frequently at different sites.  IMHO the use on dosimeter, with appropriate control dosimetry e.g. electronic instant readout devices, will give a more accurate long term measure of an individuals external exposure.  There are issues with the differences in background dose and how this should be accounted for if individuals work at different facilities.  This is sometimes where the third dosimeter may be used.  However this is not a common occurrence in the UK, it is used mainly when personnel go abroa! d.  Many of the contractors in the UK use the National Radiological Protection Board in the Uk as their dosimetry service.  This organisation has produced generic background data for most areas in the UK and this data is used when accounting for background.  I'm not sure that there will be a significant difference in natural background doserates in the UK in the vicinity of most major nuclear facilities, am I right to assume, from Sandy's comments, that this is not necessarily true of the US?

The other issue that appears to have been raised is the responsibility of the licensee in the US to monitor and therefore presumably control each individuals exposure.  This appears to be the concern that other radsafe'rs have about someone other than the licensee, undertaking the dose assessment for personnel working at their facility.  In the UK the responsibility for maintaining each individuals exposure ALARA (ALARP for the UK as defined in our regulations) is that of the radiation employer.  The radiation employer is the person who owns and controls the radiation controlled area.  So when a contractor is employed, if they have radiation workers, the contractor as the  employer is responsible for the provision of (amongst other things) that individuals dosimetry.  When they work in someone's else's facility the Radiation employer is responsible for maintaining their dose as ALARA.  However in addition there are formal requirements for Co-! operation between employers enshrined in UK law as well.

When contract personnel go to work on a different site they are required to carry with them and present to the site/facility operator a Radiation Passbook, this summarises that individuals dose that they have accrued up to the point where they last worked with radiation.  When they cease employment at a site/facility the operator of the site is required to update that individuals passbook ready for when the next commence work.

I hope this is of interest and clarifies the difference between UK requirement and those in the US and explains why the advice I gave initially differed so significantly from that proved by other list members.

Regards,
       Julian