How Synchrotrons Produce X-Rays: A Layman's Explanation

[Billy70]

Hello everyone, first time poster.

A fairly basic question: What is the mechanism by which synchrotrons produce x-rays? (in more detail than e-beam + varying magnetic flux = x-rays)

I'm also still confused as to whether the mechanism is unique to magnetic fields or the same as Bremmstrahlung radiation, although even regarding that I'm coming across conflicting information on whether it is the retardation of the electrons or the interaction between electrons and the electric fields around atoms that produces radiation.

When reading about the Maxwell equations I can find more derivations than I can shake a stick at, however a nice, layman's terms explanation seems to be lacking.

Replies very much appreciated, condescending replies not so much, but expected since this is pretty fundamental.

Thanks in advance,
Billy

 

[chrisbaird]

I don't know if I can give you more understanding then you already have without going into Maxwell's equations, but I will try. The varying magnetic fields used to confine the particles to a circular (or near-circular) track do not directly create x-rays. They are varying too slowly for this. What they do accomplish is to exert a force on the charged particles to keep them bending around the circular track. Charged particles that are accelerating radiate electromagnetic waves.

You can think of there being a radial electric field line pattern attached to every charged particle. When a particle jumps forward (accelerates), due to cause-and-effect and the finite speed of everything, the field lines far away from the particle jump forward later then the field lines close to the particle. This creates kinks in the electric field lines which travel away like waves on a string, and an electromagnetic wave is born.

The key is that there are two kinds of fundamental types of acceleration, linear and rotational, and both lead to radiation. Linear acceleration of charge would be like the current driving charges forward and backward in a straight radio antenna. But forcing a charge to curve into a circular path even if its speed is constant is also a form of acceleration and leads to radiation. Oscillatory accelerations (like in a radio antenna) lead to a train of smooth "kinks" in the field lines, so the radiation is nearly single frequency. A more constant acceleration leads to a broader smear of frequencies in the emitted radiation. So bremstrahlung and synchrotron radiation are similar in that they are non-oscillatory decelerations, but bremstrahlung typically refers to that caused by a linear deceleration, whereas synchrotron radiation is caused by an angular acceleration (curving of the charged particles by the bending magnets). Note that radiation can also be achieved in synchrotron using wigglers.

 

[xts]

Every electric charge emits radiation when accelerating. Magnetic flux has no direct importance - it just causes the beam to bend, thus to accelerate charged particles with centriprocal force.

You are right - synchrotron radiation is a kind of Bremsstrahlung radiation.

You should try really good classical (40 years old) article by Ginzburg http://cdsads.u-strasbg.fr/cgi-bin/nph-bib_query?bibcode=1969ARA&A...7..375G
- no one may explain synchrotron radiation better in a quick response on the forum.

 

[Billy70]

Thanks very much guys. Excellent explanations that have cleared it up nicely.

 

[sardar]

Hi Billy,

The mechanism by which synchrotrons produce x-rays is through a process called synchrotron radiation. This occurs when high-energy electrons are accelerated and bent by a strong magnetic field, causing them to emit electromagnetic radiation, including x-rays.

To break it down further, the electrons in a synchrotron are first accelerated to high speeds using electric fields. These high-energy electrons are then directed into a circular path by a strong magnetic field. As the electrons travel along this circular path, they are constantly changing direction due to the magnetic field, which causes them to emit synchrotron radiation.

This radiation is produced when the electrons are accelerated and decelerated by the magnetic field, which causes them to give off energy in the form of photons (particles of light). The energy of these photons corresponds to the energy of the electrons, so by controlling the energy of the electrons, scientists can control the energy of the x-rays produced.

As for your question about whether this mechanism is unique to magnetic fields or the same as Bremmstrahlung radiation, the answer is that it is a type of Bremmstrahlung radiation. Bremmstrahlung radiation is produced when charged particles, such as electrons, are accelerated or decelerated, and in the case of synchrotron radiation, this is happening due to the magnetic field.

I hope this explanation helps to clarify things for you. Synchrotrons are complex machines, but the basic principle behind their production of x-rays is the interaction between high-energy electrons and a strong magnetic field. Let me know if you have any other questions.

Best,