Re: radioactive debris

Mon, 22 Jan 1996 23:37:57 +0100 (CET)

Neil Clifford writes :

>Hazy recollections: Perhaps this (that to which you refer) is the
>'Topaz' type reactor. I recall that they caused problems with various
>astronomical satellites - possibly they resulted in false counts in
>various gamma ray experiments and the like;  it might be one reason for
>the lack of enthusiasm concerning their continued use. There was an
>interesting article on this somewhere which I could try and dig out (in
>exactly which publication and when is also hazy).

There was an issue of 'Science' devoted to this topic. It was published
on April 28, 1989, vol. 244. The articles on 'nuclear noise' are from
pp. 397-504. The subtitle says 'Unshielded reactors blind gamma ray
astronomers'. I have a nice re-print of these articles lying on my
desk here. One of the articles was written by the colleague I share an
office with. He was the first to discover these man-made signals in the
data obtained from the Gamma-Ray Spectrometer on the Solar Maximum
Mission (SMM). He found out something 'non-natural' was going on when
he saw a periodicity of the signals that was correlated to the orbital
period :-)
My colleague has this great story about how people at NASA asked him
to be 'keep it still' for now. It was only a few years later that it
was eventually published in a journal.

   Bart De Pontieu <>