[ATM] re: Large Telescope?

["Ellen Mackenzie" <mackenzieconsulting@sympatico.ca>]

Back in 1970 we were issued a scintillometer that was supposed to detect the
difference between the gamma energy levels emitted by various radioactive
materials. I am not sure what the composition of the detector crystal was,
but it was huge by the standards of the day. I placed no value on the
instrument arguing that gamma rays would be attenuated by the material they
were passing through. I was rejected for my argument until - - - 
    I was in possession of a one pound piece of pitchblende of about 95%
purity and was trying to determine if the squares law could be calculated
roughly by taking readings at various distances and logging them ( there was
a good reason). A fellow working with me walked between the sample and the
instrument and I lost about 80% of my scale reading. When I made a remark to
him about it he went over and picked up the sample and held it out and my
detector went off scale - - - then he held it behind himself and the
detector went relatively silent.
    Since I was working in a tent in the sub-arctic I had no equipment to
determine whether it was adsorbsion or attenuation, but it makes you think
twice about the same situation happening with the dark matter in space, and
other forms of the electromagnetic spectrum.


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