 |
 |
Electrons Emitting Photons
Name: Juniper
Status: other
Age: N/A
Location: N/A
Country: N/A
Date: N/A
Question:
can an electron emit an endless supply of
photons? in particle accelerators the electrons race around and
around and photons are released and studied. I wonder if the same
electrons can continue to emit photons or if they dry up?
Replies:
Sure they can emit photons without being used up.
- no electron emits any photon if it is alone and undisturbed.
It does not seem to have any internal structure with which
to do such a,
uh, distinct self-initiated action.
- what emits in a cyclotron is not just the electron,
but rather the combination of a moving electron and a
magnetic field pushing it sideways pretty hard.
This combination does not consume the electron.
It just converts some of the kinetic energy the electron has,
to the electromagnetic energy in the emitted photons.
- emitting the photon in the magnet-induced turn will slow the
electron and maybe deflect it sideways.
Will the cyclotron lose its control of the deflected
electron, or catch it and re-circulate it?
For visible light photons ~ 2eV, and fast electrons >1MeV,
the change in trajectory is pretty small,
so I think most cyclotrons will successfully snag a large
majority of the electrons
after they emit their photon of "cyclotron radiation". But
I do not really know.
Partly it depends on the equipment in the cyclotron.
Partly it depends on the sharpness of the turn.
A stronger field makes a sharper turn which makes
higher-eV photons.
(I wonder if one electron emits multiple photons to go
around a long curve?)
- there may be some small loss rate, so there will need to be some
small make-up rate of added electrons.
This is true in any case, because the vacuum in the machine
is not usually perfect.
Jim Swenson
Juniper,
Electrons emit photons because they first get energy inputted into
them (excitation) and then the release that energy
(relaxation). Through this process the electron losses or gains no
net energy, so as long as there is a source to continually excite
the electrons, they will continually relax and emit photons. The
electron remains the same before and after this process.
Matt Voss
Click here to return to the Physics Archives
| |
Update: June 2012
|
|
