it just feels so natural listening to u, like u never did smth other then providing information on videos. u could easily do a informative show or smth similar!! and I would Listen all day.. hehe. pls as seid before, keep up the good work! have a great day.
Thanks for sending me here from my comment on your x-ray scope workings. I know that a gamma splits to a positron/electron pair when passing near a heavy nucleus (which is why lead works as shielding). May I assume that the thin metal sheets referenced have a heavy nucleus such as lead, gold, or uranium? Being "more is better" in shielding, may I assume that only a small percentage of the incoming gamma rays are converted to charged pairs in each layer? Moving charged particles will spiral in a magnetic field (the old "fat screen" TV's/monitors used this to steer electrons onto a screen and make images). In a given field a positive charge and a negative charge will spin oppositely. This response can be used to separate the pair and keep them from meeting/annihilating into a new, lower energy gamma (lower energy because the moving charged particles will loose energy as their charge fields interact with surrounding matter). Is a magnetic field deliberately induced in the detector or is it shielded from magnetic fields, or is the environmental field used? Charged particles have a difficult time "flying" through materials (alpha and beta radiation are charged and generally do not penetrate deeply... in general, beta deeper than alpha). Thus, the implication that the charges make it through the stack and are sensed at the far end seems odd. Perhaps the charges are only sensed immediately after each sheet? (conducted from metal sheet to sensor once the charged particle is formed?) It s seems more likely to me that the charges would wander off causing a loss of positional information if thicker metal sheets were used. Which raises another question... the interleaved charge-sensing layers... Do they detect only from a sheet on one side, or are charge sensors placed on both faces of the metal sheet? So many things to learn.
The metal sheets are made of tungsten, which is a pretty heavy metal, but the sheets are incredibly thin - more of a foil than a proper sheet of metal. The gamma rays are high enough energy that they can make it through many layers of this foil, and the sensors are interlaced with the foils. This lets them detect particles from any direction. The bigger issue is filtering out unwanted cosmic rays that look like gamma rays, and also filtering out gamma rays that originate from Earth that we aren't interested in here. As far as I know, I don't think there is any magnetic field to direct the particles here, as the goal is to see the path they follow and use that to work out where the ray originated. Hope this help" :)
Hi @Chris. I hope you get to see this physics question cos its been racking my brain since 6th form college...and I'm sure you're a physics boffin. If one had a metal strip and they wound it into a coil, and then they squeezed that coil into a bottle top such that it remained wound up...and then they added acid into the bottle top so that the acid reacted with the metal and dissolved it. Where would the strain energy that was in the coil go to?
Have been looking forward to this video! An excellent description on how a gamma ray telescope works. Well done Chris, and many thanks.
Thanks David, glad you liked it!
Wow ,Fascinating ;didn't ever think about how the Gamma Ray Telescopes worked. Didn't know much about the Fermi Space Tele either.
it just feels so natural listening to u, like u never did smth other then providing information on videos.
u could easily do a informative show or smth similar!!
and I would Listen all day.. hehe.
pls as seid before, keep up the good work!
have a great day.
Thanks for sending me here from my comment on your x-ray scope workings.
I know that a gamma splits to a positron/electron pair when passing near a heavy nucleus (which is why lead works as shielding). May I assume that the thin metal sheets referenced have a heavy nucleus such as lead, gold, or uranium? Being "more is better" in shielding, may I assume that only a small percentage of the incoming gamma rays are converted to charged pairs in each layer? Moving charged particles will spiral in a magnetic field (the old "fat screen" TV's/monitors used this to steer electrons onto a screen and make images). In a given field a positive charge and a negative charge will spin oppositely. This response can be used to separate the pair and keep them from meeting/annihilating into a new, lower energy gamma (lower energy because the moving charged particles will loose energy as their charge fields interact with surrounding matter). Is a magnetic field deliberately induced in the detector or is it shielded from magnetic fields, or is the environmental field used? Charged particles have a difficult time "flying" through materials (alpha and beta radiation are charged and generally do not penetrate deeply... in general, beta deeper than alpha). Thus, the implication that the charges make it through the stack and are sensed at the far end seems odd. Perhaps the charges are only sensed immediately after each sheet? (conducted from metal sheet to sensor once the charged particle is formed?) It s seems more likely to me that the charges would wander off causing a loss of positional information if thicker metal sheets were used. Which raises another question... the interleaved charge-sensing layers... Do they detect only from a sheet on one side, or are charge sensors placed on both faces of the metal sheet? So many things to learn.
The metal sheets are made of tungsten, which is a pretty heavy metal, but the sheets are incredibly thin - more of a foil than a proper sheet of metal. The gamma rays are high enough energy that they can make it through many layers of this foil, and the sensors are interlaced with the foils. This lets them detect particles from any direction. The bigger issue is filtering out unwanted cosmic rays that look like gamma rays, and also filtering out gamma rays that originate from Earth that we aren't interested in here. As far as I know, I don't think there is any magnetic field to direct the particles here, as the goal is to see the path they follow and use that to work out where the ray originated. Hope this help" :)
Hi @Chris. I hope you get to see this physics question cos its been racking my brain since 6th form college...and I'm sure you're a physics boffin.
If one had a metal strip and they wound it into a coil, and then they squeezed that coil into a bottle top such that it remained wound up...and then they added acid into the bottle top so that the acid reacted with the metal and dissolved it. Where would the strain energy that was in the coil go to?
Thanks. Very interesting and informative
So awesome. Thank you!!
Thanks! :)
Wow I had no idea they worked liked that, that's amazing! Great video as always!
Thanks! :)
Thanks for another awesome video! Keep it up man, all the best :)
Thanks a lot! Will do!
What would you see if you pointed a gamma ray telescope at the earth, from say, 60,000ft?
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