Recent content by mitch_1211

hey everyone, so i know to calculate the nyquist frequency for a system (for digital imaging in PET and SPECT in this example) given the pixel size its just f = 1/ 2 * pixel size but for pixels that are rectangular and have a larger and smaller dimension, which one should be used here...

Ya i was just thinking that actually. You got to round up to an integer value for a byte right? (no rhyme intended)

Homework Statement The minimum storage capacity required to store the information in a digital radiographic exam that consists of a 1024 – 1024 matrix, 12 bit deep, acquired at 30 frames per second for 10 seconds is _____ megabytes. 1 37 600 695 2500 Homework Equations The...

thanks for the replies... I figured out that photoelectric absorption occurs with *inner* shell electrons hence resulting in a re-shuffle involving significant energies and so the Auger electrons or characteristic x-rays are produced. However Compton scattering events predominantly occur...

Thanks for getting back to me :) I should have been more specific, I wasnt referring to the photoelectric effect that describes the photocurrent produced from metals that you explained. I should have said photoelectric absorption as in one of the interaction methods that gamma rays and x-rays...

Hi All, So the photoelectric effect is the phenomenon where an orbital electron fully absorbs an incoming photon (assuming the energy of the photon is greater than the binding energy of the electron) and is ejected from its shell. The electron can then undergo its own interactions in the...

any idea what 'coincidence summing effects' might be in relation to gamma-gamma coincidence?

that makes sense, thanks for that :)

hey everyone, I know gamma-gamma coincidence detection is used to somehow determine the activity of a radioactive source, I was wondering if someone could explain to me in fairly simple terms how this is done? Also, is determining activity generally the only application for gamma-gamma...

yea exactly, pushing a block to the left and performing work on it is the same as pushing it to the right

just one more thing, if considering the particles to be relativistic, is it still sufficient to apply simple energy conservation? Or should the 4-vector formalism be used?

I should mention that \epsilon is an arbitrary deformation parameter associated with the ellipsoid and can be factored out

So I think, as a rule of thumb that for fission to be possible \frac{Z^2}{A}\geq47 I want to be able to derive this relationship though.. If a nucleus deforms into an ellipsoid, its surface area can be described by 4\piR2(1+\frac{2}{5}\epsilon^2 + ...) call this X And its Coulomb...

thanks for clearing that up :)

So is it really as simple as E\gamma = (En+Ep) - Ed?