[ RadSafe ] Fwd: Pilots UV-A radiation exposure
JPreisig at aol.com
JPreisig at aol.com
Sun Dec 28 21:36:14 CST 2014
Radsafe,
In an accelerator environment, with time-varying beam conditions,
one probably needs 7 Bonner detectors, plus the plastic scintillator.
(Brookhaven AGS, RHIC etc.). In a reactor environment, one could probably use
one detector (unmoderated = bare) plus one detector over which you put on the
various Bonner detector moderators and make a series of 10-minute or so
detector counts in about an hour or so. One could also have an Andersson
Braun nearby to make sure the reactor is on consistently. A plastic
scintillator detector might also be helpful...
Unfolding the data, use BON4/BON5, Louhi, Maxed (advanced unfolding)
or other such computer codes. See Paterson and Thomas's book for details
or Cossairt's Accelerator HP course notes. BON4/BON5 and some of the other
computer codes are available from ORNL RSICC (Radiation Shielding
Information Center). With BON4/BON5,plot the results by hand, because the plotting
software doesn't really give nice understandable visual results. My good
results of Bonner work at the BNL AGS (1996-1998) might be available from
Henry Kahnhauser (BNL). Or Not??? I also wrote a Bonner/plastic
scintillator procedure, which also might be available from Kahnhauser. or Not???
At the BNL AGS, one usually gets flux density spectrum results which
give 3 peaks or so. A thermal neutron peak, an evaporation neutron peak at
about 1 MeV and a cascade neutron peak at energies higher than 1 MeV.
Norm Rohrig's research note in Health Physics (or Cossairt) explains how the
results should be plotted. Bonner Spectrometer calibrations take a fair
amount of time.
Questions, just email me.... Joe Preisig
In a message dated 12/28/2014 10:08:57 Pin Health in Health Physics.M.
Eastern Standard Time, tdc at xrayted.com writes:
Flying a whole set of Bonner Spheres is not a trivial matter - been
there done that! With McCaslin in fact!
For just dose - an Andersson Braun detector would be easiest - although
not light weight - especially the extended high energy version.
On 12/22/2014 7:49 PM, JPreisig at aol.com wrote:
> Joe,
>
> I guess there's an Ed Bramlitt. I also believe there's a
Bramblett,
> Ewing and Bonner --- inventors of Bonner Neutron Spectrometry. See
> Patterson and Thomas's Accelerator Health Physics. See also Cossairt's
> Accelerator Health Physics course notes/manual.
>
> Joe Preisig
>
> PS Badges are OK in airplanes....but one really needs a Neutron
> Spectrometer (for thermal neutron to 20 MeV energies) and a plastic
scintillator
> (n,2n reaction) for 20 MeV to 400 MeV neutrons. Scintillator see the
back end
> of Patterson and Thomas's Accelerator Health Physics book (McCaslins's
> plastic scintillator lab exercise).
>
>
>
> a message dated 12/21/2014 2:36:32 P.M. Eastern Standard Time,
> jjshonka at shonka.com writes:
>
> Hans
>
>
> I am quite interested in your badge results, and what would be a
> significant radiation exposure. You have an unusually high number of
frequent flyer
> miles. If we assume total neutron plus gamma of 500 mrem (5 mSv) per
> 100,000 frequent flyer miles or per year, and 15 rem over a 3 million
mile or
> 30 year career, I have the following questions: (1) were your badges
> neutron sensitive (80% of GCR dose is due to neutrons)?; (2) how often
were
> they read out (quarterly, monthly?); (3) were many of your miles extra
credits
> rather than actual miles flown (e.g. first class gets 2X miles)?; (4)
were
> your miles collected evenly or did you travel more extensively during
some
> fraction of your career?; (5) what would you say the reporting limit or
> detection limit of the badges was (e.g any reading less than 10 mrem
(0.1
> mSv) reported as 0)?; (6) were your badges used for work and did they
have
> measureable exposure from sources other than background plus your
flight time?
>
>
> Ed Bramlitt and I have a note in the January, 2015 issue of Health
Physics
> that discusses intermittent sources of exposure to aircrew, including
> solar proton, neutron and gamma events and terrestrial gamma flashes.
About 1%
> of the 1200 Terrestrial gamma flashes that are large enough to be
detected
> by satellites that occur each day (world-wide) approach estimated doses
in
> aircraft of up to 30 to 100 mSv, for example. Although rare, these
likely
> would have been observed on your badge. The more numerous dose of 10
mSv
> or greater (my estimate of the lower limit of detection for the GBM
> detectors on board FERMI) might also be detectable, however, presumably
even more
> numerous but undetectable lower dose TGFs (below 10 mSv) might not be
> detected. I am interested in how large one of those events could have
been
> without your noticing an unusual reading.
>
>
> I assume the background control badges were at your place of
employment.
> Finally, (7) For example, if you typically had 12 flights per quarter,
and
> one of those flights encountered a source that provided 1,000 mrem (10
mSv)
> 80 % of which was neutron and only 200 mrem (2 mSv) was gamma, would you
> have noticed it as an unusual badge reading?
>
>
> Joe Shonka
>
>
>
>
>
>
> Sent from Windows Mail
>
>
>
>
>
> From: Hans J Wiegert
> Sent: Saturday, December 20, 2014 7:18 PM
> To: The International Radiation Protection (Health Physics) Mailing List
>
>
>
>
>
> For what it's worth.
>
> I am not so sure about this. During my career I traveled almost 3
million
> miles on various airlines with my seating preference being a window
seat.
> Never noticed anything like this. As a side note, on almost all of those
> trips I carried a film badge on me and in recent years the Landauer
Luxel
> OSL badge. The badges never showed any significant radiation exposure.
>
> Best Regards,
>
> Hans
>
> *Retirement is, when the only day you have to set your alarm clock is
> Sunday - so you are not late for church!*
>
> On Thu, Dec 18, 2014 at 2:19 PM, Chris Alston <achris1999 at gmail.com>
wrote:
>> This is easy to believe. I, as a passenger, have gotten a pretty good
>> tan, mostly on one side of my face, on just one trip from Seattle to
>> San Diego. Fortunately, I had a window seat on the other side of the
>> aircraft (DC-9 family, for whatever it is worth) on the northward
>> return flight, to "touch up" the other side of my face, else I would
>> have looked like that arch-criminal in the Batman comics.
>>
>> Cheers
>> cja
>>
>> On Wed, Dec 17, 2014 at 8:36 PM, ROY HERREN <royherren2005 at yahoo.com>
>> wrote:
>>> Hopefully the following isn't too "off topic", given that the article
> is
>> dealing with UV-A radiation.
>>
>
http://media.jamanetwork.com/news-item/airline-pilots-can-be-exposed-to-cockpit-radiation-similar-to-tanning-beds/
>> > Airline Pilots Can Be Exposed to Cockpit Radiation Similar to
Tanning
>> Beds
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