Asimov,

I believe you have misinterpreted the geometry. The detector array is
some distance behind the aperture array, perhaps one meter or more. The
concept is that of a simple shadow mask. There are 52000 shadows on
32000 detectors, so the details of the computation are probably a bit
complex.

I recommend a paper by Scott Barthelmy, which is available at

http://swift.gsfc.nasa.gov/docs/swif...SBarthelmy.pdf


73,
Gene
W4SZ

Asimov wrote:
Hi,

Say, I've got a question about something I've read about the Swift
gamma ray detection satellite. It's detector consisted of an antenna
composed of 52,000 lead blocks arranged by computer generated
pseudo-random locations and glued to the back of a sheet of 4x8
plywood. The actual detectors where located in the spaces between the
blocks. It wasn't mentioned but I think these were probably crystals
which give off a pulse of electricity every time they are struck by a
gamma ray.

Anyways my question is, in your opinion, what is the purpose of the
pseudo random arrangement of this "apperture mask" antenna? I suspect
it has something statistical related to the nature of ambient noise
signals. I tried making a pc simulation of this but I get the same
answer whether the array is in rows or pseudo-random. I tried with
noise but I saw no reduction. I haven't tried adding a signal to the
noise in the simulation yet though...

A*s*i*m*o*v

... Three types of lies: lies, damn lies, and statistics - Mark Twain.