Re: neutron flux in space

["Scott D. Kniffin" <Scott.D.Kniffin.1@gsfc.nasa.gov>]

Hi again,

I grant that neutrons are there, just that in comparison to all the other
stuff hitting you in space, the neutron term is rather less significant
than any of the others.  Besides, at 10eV, they're getting soaked up by the
outter (probably aluminum) skin of your spacecraft and the resultant
activation product is not around very long in terms of what's coming back
at earth in hte event of a disaster. Plus there's scattering/reflection and
the decay products of the activated Al (2.6MeV beta and 1.8MeV gamma) still
has to go into the spacecraft.  The cosmic rays are much worse in terms of
what damage they do to electronic components, fortunately these are also
(except in certain orbits) minimal as well.  
I hadn't meant to turn this into a mess, I thought I was pointing out a
humorous glitch (which after further review, what I wrote wasn't as funny
as it sounded before I had my hot chocolate) in a note reminding us to
watch what we say.  Sorry for the confusion, I'll slap myself a few times
in the morning before I reply from now on, I promise. ;)

Scott Kniffin

mailto:Scott.D.Kniffin.1@gsfc.nasa.gov
RSO, Unisys Corp. @ Lanham, MD
CHO, Radiation Effects Facility, GSFC, NASA, Greenbelt, MD

The opinions expressed here are my own.  They do not necessarily represent
the views of Unisys Corporation or NASA.  This information has not been
reviewed by my employer or supervisor.  

At 13:16 05/06/98 -0500, you wrote:
>Depending on the circumstances this parameter can change dramatically
since many more neutrons are produced by the very high energy cosmic rays
(ions) when they interact with matter (e.g., the air containment shell of
your space vehicle).  The NCRP meeting this year had lots of neat data on
this topic.
>
><color><param>0000,ffff,ffff</param>Disclaimer:  the above are the
>personal musings of the author, and do not represent any past, present,
>or future position of NIST, the U.S. government, or anyone else who might
>think that they are in a position of authority.
>
></color><color><param>8080,0000,0000</param>Lester Slaback, Jr. 
>[Lester.Slaback@NIST.GOV]
>
>NBSR Health Physics
>
>Center for Neutron Research
>
>NIST
>
>Gaithersburg, MD  20899
>
>301 975-5810</color>
>
>