[ RadSafe ] Fwd: Pilots UV-A radiation exposure

Ted de Castro tdc at xrayted.com
Sun Dec 28 21:26:57 CST 2014


We did several flights - mostly in a military transport but at least two 
in a U2 (of course the instruments flew the U2 - not us - not much space 
in a U2!!)!

We used them many many times around the accelerators at LBL (ground 
based) but once we proved the technology -  by bonner sphere comparison 
- we mainly used what we called the "proportional energy" counter ---- 
described in Pattterson and Thomas --- and a flux monitor (moderated 
BF3).  Then eventually we verified the high energy Andersson Braun and 
deployed them all around the lab - in close and at the perimeter.

One day at the Super Hilac we compared the 3 inch 9 inch bonner sphere 
method with the Proportional Energy and the extended Andersson Braun - 
and of course the full bonner sphere array, in cooperation with Dale 
Hankins LLNL (he did the 3 inch 9 inch).  High energy AB won, then PE 
and lastly 3inch/9inch.

We also did plastic scintillator activation but some one else did that 
(Allen R. Smith) and so I don't have much details on that.


On 12/28/2014 7:14 PM, JPreisig at aol.com wrote:
> xrayted,
>   
>       Doing 7 Bonner detectors on the ground and  activating a plastic
> scintillator on the ground is also a challenge.   detectors =  bare, Cd-covered,
> 3 inch, 5 inch, 8 inch, 10 inch, 12  inch  plus plastic scintillator.
> But it can be done.
>   
>       Joe Preisig
>   
>   
>    
>   
> In a message dated 12/28/2014 10:08:57 P.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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