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RE: In-flight radiation doses



In the midst of all of this was a reference to on-line dose calculators. There's CARI, which is on a U.S. FAA web site (http://www.cami.jccbi.gov/AAM-600/Radiation/600radio.html) and EPCARD, which is on the German National Research Center for Environment and Health web site (http://www.gsf.de/epcard/eng_start.php). 



-----Original Message-----

From: Bill Prestwich [mailto:prestwic@mcmaster.ca] 

Sent: Monday, July 12, 2004 7:53 AM

To: ?????? ??

Cc: 'Franz Schoenhofer'; 'John Jacobus'; radsafe@list.vanderbilt.edu

Subject: Re: In-flight radiation doses





I just want to thank Dr. Brickner both for his interesting posting and giving us another example of just how worthwhile radsafe is. Cheers, Bill Prestwich



?????? ?? wrote:



> Well, The last Concord plane has been grounded already, so my remark 

> is of theoretical value only (if any...). I can't understand the 

> reason why those Concords were ordered to lower altitude in the event 

> of a solar flare. While  changing altitude from about 80000 feet to 

> 39000 feet, lowering the exposure to half the dose per unit of time, 

> they had to cut the speed and doubling the flight (=exposure)time . 

> The net change in radiation exposure would be about 0.I have raised 

> that question to FAA men during the IRPA 2000 they gave me a twisted 

> answer that the most logical part of it was that it only happaned once 

> and that Concord flights are phasing out anyway...

>

> Dov (Dubi) Brickner MD

> Beer-Sheva       ISRAEL

>

> -----Original Message-----

> From: owner-radsafe@list.vanderbilt.edu 

> [mailto:owner-radsafe@list.vanderbilt.edu] On Behalf Of Franz Schoenhofer

> Sent: Friday, July 09, 2004 12:37 PM

> To: John Jacobus; radsafe@list.vanderbilt.edu

> Subject: In-flight radiation doses

>

> There was a paper on this topic in Health Physics about 10 years ago. 

> Since the Concord(e)s flew so high up (wasn't it 18 000 meters?), that 

> the doses from solar flares were regarded as not negligible, a 

> measurement device was working automatically during flight to warn in 

> the case of elevated doses, whereupon the plane flew to a lower 

> altitude.

>

> More on this topic:

>

> There is still little known about the exact doses from cosmic rays, 

> especially about the quality factors for larger particles. The neutron 

> component of the cosmic radiation plays an important role and even 

> this part of the radiation can only be measured with more 

> sophisticated instrumentation than a TLD dosimeter or a Geiger counter 

> would be, not to talk about the other components.

>

> In light of this fact it is difficult for me to understand, that - 

> though radiation doses cannot be easily and/or exactly determined - 

> there exist regulations, depending on radiation doses. The European 

> Union Directive obliges the member states to install regulations for 

> in-flight doses. The regulations of member states which I know use the 

> concept, which is used also for regulations with respect to Naturally 

> Occurring Radioactive Material (NORM): Members of the public are not 

> supposed to receive doses above 1 mSv/y. If professional of the flight 

> crew (which are not regarded as radiation workers!) probably or likely 

> are to exceed 6 mSv/y, they have to be monitored. The employer has to 

> care for reduction of the doses. In any case 20 mSv/y must not be 

> exceeded.

>

> Regarding "monitoring" of flight crews: Since it is not possible to 

> have a simple device like a TLD for measurement (see above), a totally 

> different approach has to be chosen:

>

> Despite the above described inherent problems to accurately determine 

> a "real" dose, really a lot of research has been done on the aspect of 

> in-flight doses, both on behalf of air lines, national organisations 

> and international organisations like the European Union. The basic 

> facts are relatively well known, one being the variation of cosmic 

> radiation intensity with elevation, latitude, season etc. So an 

> overall pattern is known. The sun activity is very well monitored by 

> astronomers and the cycles governing it on a large scale is well 

> known. I know of British Airways that they use computers to calculate 

> the expected doses according to the flight routes. A few BA airplanes 

> carry measurement devices and can transmit instantly changes like big 

> solar flares. This enables BA to assign doses to every single member 

> of a crew. Crew members approaching their 6 mSv/y will be assigned to 

> flights with lower expected doses. According to estimates from BA the 

> crew of long-haul flights will normally receive between 5 and 8 mSv/y, 

> so the problem is not really dramatic and can be rather easily 

> overcome, making special "personal" monitoring unnecessary. Crews 

> working on short-haul flights are according to several national 

> studies not at all at risk to exceed 6mSv/y.

>

> There is a web-site, which you can use to calculate your dose on your 

> next flight, but I do not have the address at hand. Anybody interested 

> in details is welcome to contact me and I will do my best to find 

> material in my still unsorted records. An alternative is of course to 

> use Google or another Search Engine ("in-flight radiation"), though 

> they usually do not yield highly scientific information.

>

> Best regards,

>

> Franz

>

> ----------------------------------------------------------------------

> ----

>

> -----Ursprüngliche Nachricht-----

> Von: owner-radsafe@list.vanderbilt.edu 

> [mailto:owner-radsafe@list.vanderbilt.edu]Im Auftrag von John Jacobus

> Gesendet: Freitag, 09. Juli 2004 15:45

> An: radsafe@list.vanderbilt.edu

> Betreff: Re: CNN article

>

> I believe that the Concorde jetliners had pressurized

> ion chambers in the crew's cabin to provide real-time exposure 

> results.  If a solar event occurred, the crew were supposed to reduce 

> their altitude, which I believe only occurred once.  I have yet to 

> find any indication if the exposure data was every recorded.

>

>  --- JGinniver@AOL.COM wrote:

> >

> > In a message dated 7/7/04 1:04:47 am,

> > rujohnso@nmsu.edu writes:

> >

> >

> > > I'm curious now what the actual doses are to

> > full-time international

> > > airline crews. Does anyone know, per flight or per

> > annum? I've been asked this

> > > question before in the radiation safety class I

> > teach, but I don't know. If

> > > european agencies monitor crew doses, then they

> > must fly with TLD or similar

> > > badges.

> > >

> >

> > There is quite a good summary by the UK National Radiological 

> > Protection Board at the following URL

> >

> >

> http://www.nrpb.org/publications/bulletin/no4/editorial.htm

> >

> > It as my understanding that doses to aircrew could

> > not be accurately

> > estimated using simple passive detectors such as

> > TLDs.   Instead special monitoring

> > equipment has been developed by the NRPB which is

> > carried on the aircraft to

> > provide dosimetric information and that by using

> > different routes/flight

> > paths/altitudes it is possible to estimate the doses

> > to aircrew.

> >

> > Regards,

> >      Julian

> >

>

> =====

> +++++++++++++++++++

> "To be persuasive, we must be believable,

> To be believable, we must be credible,

> To be credible, we must be truthful."

> Edward R. Murrow

>

> -- John

> John Jacobus, MS

> Certified Health Physicist

> e-mail:  crispy_bird@yahoo.com

>

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