[ 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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