- #1
artis
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So I'm reading up on this device and what I get is that in all electron guns once the electrons are emitted they would tend to repel one another so in order to make the beam focused instead of spread out across, one uses magnetic fields in the electron microscope,
So after the focused beam hits and travels through the target thin layer it is then "refocused" at the other side in order to make the otherwise small beam point now spread out over a film or window on which the fine little details could get enlarged for visual viewing. So far so good? Here is what I don't get. an electron traveling perpendicularly to a B field has the Lorentz force exerted upon it which causes it;'s deflection perpendicularly to both the field and it's trajectory, in vacuum free space it makes it spiral.
So let's say the electron came out from the think target layer at a particular spot, now it would fly downwards to hit the (phosphor ?) on the screen forming a pixel of information that it carries , but the secondary magnetic lens deflects the electron and it hits the screen at some random place, if this happens for each electron how come a picture be formed that represents the material?Also is it not the case that each electron has slightly different kinetic energy after it has come out from the layer of target material that it has been shot through? So having a different kinetic energy each electron would be deflect slightly differently in the magnetic lens?
So after the focused beam hits and travels through the target thin layer it is then "refocused" at the other side in order to make the otherwise small beam point now spread out over a film or window on which the fine little details could get enlarged for visual viewing. So far so good? Here is what I don't get. an electron traveling perpendicularly to a B field has the Lorentz force exerted upon it which causes it;'s deflection perpendicularly to both the field and it's trajectory, in vacuum free space it makes it spiral.
So let's say the electron came out from the think target layer at a particular spot, now it would fly downwards to hit the (phosphor ?) on the screen forming a pixel of information that it carries , but the secondary magnetic lens deflects the electron and it hits the screen at some random place, if this happens for each electron how come a picture be formed that represents the material?Also is it not the case that each electron has slightly different kinetic energy after it has come out from the layer of target material that it has been shot through? So having a different kinetic energy each electron would be deflect slightly differently in the magnetic lens?