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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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