Gamma and beta radiation in accelerators?

[Baroo]

How ,exactly, are gamma and beta radiations produced in electron accelerators? Is the process for gamma almost the same as X-ray in linear accelerators? What about beta?

 

[mathman]

Beta rays are electrons.

 

[PSRB191921]

There are no beta rays produced by an Accelerator. Gamma rays are produced by interaction of electrons (bremsstrahlung).

 

[geoelectronics]

There are no beta rays produced by an Accelerator. Gamma rays are produced by interaction of electrons (bremsstrahlung).

Hello. May I ask a question concerning definitions (?), because clearly I am out of step with some on this forum. It is probably minor but is a big deal to me as a Nuclear Metrologist. We are trained to take measurements and MUST use certain terminology to describe those results. If this is not proper or I am in the wrong place, please give guidance.

Thank you.
George Dowell

 

[PSRB191921]

What definitions are out of step ?

 

[geoelectronics]

What definitions are out of step ?

My definitions (the definitions imposed upon Gamma Spectrometry practitioners) are definitely out of step and quite different from those that PF instructors/mentors often (always?) use, and the one you just used. It would really be great if a Glossary would be posted (maybe it is and I can't find it?). I will be happy to move this to the appropriate forum if advised..

The main example is the use of the word Gamma Ray: "Gamma rays are produced by interaction of electrons (bremsstrahlung)"

let me explain-

In the scientific world I inhabit (nuclear metrology) Gamma Ray means simply, but strictly: "an electromagnetic photon produced within an a atomic nucleus", while on PF board it is used as a description of any photon within a certain segment of the electromagnetic spectrum.

In our lexicon, a photon produced in the atomic electron shell are X-Rays, and special cases like Bremsstrahlung are produced by charged particles during acceleration and/or decelleration. The list includes Annihilation Radiation from anti-particle annihilation, etc.

Here on PF I was ridiculed for some statement involving photons with the comment: "Are you CRAZY? Photons are PARTICLES". And another time "GRAVITY IS NOT A FORCE, it is a region in space-time".

Yes we need a glossary, but we also need respect between disciplines.
A lot of us are out here doing mundane room-temperature physics.

George Dowell

 

[ZapperZ]

My definitions (the definitions imposed upon Gamma Spectrometry practitioners) are definitely out of step and quite different from those that PF instructors/mentors often (always?) use, and the one you just used. It would really be great if a Glossary would be posted (maybe it is and I can't find it?). I will be happy to move this to the appropriate forum if advised..

The main example is the use of the word Gamma Ray: "Gamma rays are produced by interaction of electrons (bremsstrahlung)"

let me explain-

In the scientific world I inhabit (nuclear metrology) Gamma Ray means simply, but strictly: "an electromagnetic photon produced within an a atomic nucleus", while on PF board it is used as a description of any photon within a certain segment of the electromagnetic spectrum.

In our lexicon, a photon produced in the atomic electron shell are X-Rays, and special cases like Bremsstrahlung are produced by charged particles during acceleration and/or decelleration. The list includes Annihilation Radiation from anti-particle annihilation, etc.

Here on PF I was ridiculed for some statement involving photons with the comment: "Are you CRAZY? Photons are PARTICLES". And another time "GRAVITY IS NOT A FORCE, it is a region in space-time".

Yes we need a glossary, but we also need respect between disciplines.
A lot of us are out here doing mundane room-temperature physics.

George Dowell

But you are using the definition restricted to within your profession, and thinking that that is the ONLY path to create gamma rays.

Gamma rays, first and foremost, is an electromagnetic wave! How and where it comes from is irrelevant in the general sense of its identity, as long as it falls within the frequency spectrum that we loosely define to be "gamma rays".

You may be familiar with nuclear processes that generate gamma rays, but it doesn't mean that this is the ONLY mechanism. In the context of this thread, i.e. particle accelerators, high energy electrons being stopped very quickly by either a beam-stop or something else can create high-frequency "braking radiation", i.e. bremsstrahlung.

I would not be surprised if, in a few years, advances in beam physics and insertion devices would have advanced enough that we will get gamma radiation (we already have hard x-rays) from FEL and synchrotron beamlines. Again, no nuclear processes there either!

Zz.

 

[geoelectronics]

My definitions (the definitions imposed upon Gamma Spectrometry practitioners) are definitely out of step and quite different from those that PF instructors/mentors often (always?) use, and the one you just used. It would really be great if a Glossary would be posted (maybe it is and I can't find it?). I will be happy to move this to the appropriate forum if advised..

The main example is the use of the word Gamma Ray: "Gamma rays are produced by interaction of electrons (bremsstrahlung)"

let me explain-

In the scientific world I inhabit (nuclear metrology) Gamma Ray means simply, but strictly: "an electromagnetic photon produced within an a atomic nucleus", while on PF board it is used as a description of any photon within a certain segment of the electromagnetic spectrum.

In our lexicon, a photon produced in the atomic electron shell are X-Rays, and special cases like Bremsstrahlung are produced by charged particles during acceleration and/or decelleration. The list includes Annihilation Radiation from anti-particle annihilation, etc.

Here on PF I was ridiculed for some statement involving photons with the comment: "Are you CRAZY? Photons are PARTICLES". And another time "GRAVITY IS NOT A FORCE, it is a region in space-time".

Yes we need a glossary, but we also need respect between disciplines.
A lot of us are out here doing mundane room-temperature physics.

George Dowell

But you are using the definition restricted to within your profession, and thinking that that is the ONLY path to create gamma rays.

Gamma rays, first and foremost, is an electromagnetic wave! How and where it comes from is irrelevant in the general sense of its identity, as long as it falls within the frequency spectrum that we loosely define to be "gamma rays".

You may be familiar with nuclear processes that generate gamma rays, but it doesn't mean that this is the ONLY mechanism. In the context of this thread, i.e. particle accelerators, high energy electrons being stopped very quickly by either a beam-stop or something else can create high-frequency "braking radiation", i.e. bremsstrahlung.

I would not be surprised if, in a few years, advances in beam physics and insertion devices would have advanced enough that we will get gamma radiation (we already have hard x-rays) from FEL and synchrotron beamlines. Again, no nuclear processes there either!

Zz.

Would you mind very much telling me the definition you folks use for the word "Ray"?
Thank you.

George Dowell

 

[ZapperZ]

Would you mind very much telling me the definition you folks use for the word "Ray"?
Thank you.

George Dowell

Would you mind tell me if you actually understood the main point that I made regarding your restricted definition of gamma "ray" or "photons"?

Zz.

 

[Dr.AbeNikIanEdL]

But you are using the definition restricted to within your profession, and thinking that that is the ONLY path to create gamma rays.

Well, according to this definition it is the only path (as gamma radiation is defined to be radiation from a nucleus, in that sense the gamma and x-ray spectrum overlap). I have to agree that I find this to be a pretty standard definition, and if the question is "How is gamma radiation produced, in difference to X-rays" it is important to know what definition one uses for these words (in particular if beta radiation is in the mix, that also usually is reserved for electrons/positrons from nuclear decays).

 

[ZapperZ]

Well, according to this definition it is the only path (as gamma radiation is defined to be radiation from a nucleus, in that sense the gamma and x-ray spectrum overlap). I have to agree that I find this to be a pretty standard definition, and if the question is "How is gamma radiation produced, in difference to X-rays" it is important to know what definition one uses for these words (in particular if beta radiation is in the mix, that also usually is reserved for electrons/positrons from nuclear decays).

But since WHEN did the SOURCE of EM radiation became part of the definition of what it is? Don't you think this is rather odd?

That like insisting that all radio waves must be defined as EM radiation created by antennas!

Regardless of what any definition is used, the FACT that I have already shown that gamma rays CAN and ARE being generated via other means than nuclear processes means that the definition is clearly incomplete and inadequate here.

Zz.

 

[geoelectronics]

Would you mind tell me if you actually understood the main point that I made regarding your restricted definition of gamma "ray" or "photons"?

Zz.

Yes I heard you, and I agree Gamma Rays are photons.

Gamma Rays as defined by Australian Government, Austaralian Radiation Protection and Nuclear Safety Department:
What are gamma rays?

"A gamma ray (g) is a packet of electromagnetic energy (photon) emitted by the nucleus of some radionuclides following radioactive decay. Gamma photons are the most energetic photons in the electromagnetic spectrum."

Here they split the definition I use and the one you use. If they are created in a Nucleus, they cannont be the most energetic photon possible. Those statements are mutually exclusive. There is no limit to the kinetic energy a physical particle (electron, proton etc) can carry. There is a discreet limit to what an elemental nucleus can carry, defined by its nuclear binding energy.

US NRC: "Radioactive decay

"The spontaneous transformation of one radioisotope into one or more different isotopes (known as “decay products” or “daughter products”), accompanied by a decrease in radioactivity (compared to the parent material)." This is the definition we (must) use. Merely emitting energy in the form of a gamma ray after the fact has a name too, IT= Isomeric Transition, note this is the daughter doing that not the parent.

Now what are you basic definitions.

George Dowell

 

[Dr.AbeNikIanEdL]

But since WHEN did the SOURCE of EM radiation became part of the definition of what it is?

I am too young to know particularly much about the history of this terminology, I just know that these two definitions (either by wavelength range or by source) are around (https://en.wikipedia.org/wiki/Gamma_ray#Distinction_from_X-rays), and was pointing out that it is indeed important to know which one is used to answer the OP.

 

[ZapperZ]

Yes I heard you, and I agree Gamma Rays are photons.

Gamma Rays as defined by Australian Government, Austaralian Radiation Protection and Nuclear Safety Department:
What are gamma rays?

"A gamma ray (g) is a packet of electromagnetic energy (photon) emitted by the nucleus of some radionuclides following radioactive decay. Gamma photons are the most energetic photons in the electromagnetic spectrum."

And considering that I've shown where this definition is violated, who is at fault here?

US NRC: "Radioactive decay

"The spontaneous transformation of one radioisotope into one or more different isotopes (known as “decay products” or “daughter products”), accompanied by a decrease in radioactivity (compared to the parent material)." This is the definition we (must) use. Merely emitting energy in the form of a gamma ray after the fact has a name too, IT= Isomeric Transition, note this is the daughter doing that not the parent.

That is not the definition of gamma rays. That is the definition of radioactive decay.

Now what are you basic definitions.

It is EM radiation within a loosely defined range of frequency shown in the spectrum of EM radiation.

https://www2.lbl.gov/MicroWorlds/ALSTool/EMSpec/EMSpec2.html
It has nothing to do with how or where it was created.

In the end, what name you give it doesn't affect it one bit. However, the physics that is associated with it does matter, and erroneously thinking that all EM radiation within this range can ONLY be generated via nuclear reaction is patently FALSE!

Think about this: If I have a clump of electrons, and I jiggle it back and forth fast enough, I can generate EM radiation/photons at any frequency that I want, including gamma photons. This, naively, is what we do with those wigglers and undulators insertion devices in FELs and synchrotron centers all over the world. Nowhere in there do I require a radioactive decay.

Zz.

 

[Dr.AbeNikIanEdL]

And considering that I've shown where this definition is violated, who is at fault here?

You just showed that two definitions of the word "gamma radiation" are incompatible.

Electromagnetic Spectrum
It has nothing to do with how or where it was created.

So on the right edge of this picture there are "Hard X Rays" and "Gamma Rays" with the same wavelength/energy. What is then the difference between these two?

thinking that all EM radiation within this range can ONLY be generated via nuclear reaction is patently FALSE!

You seem to have this backwards. If you adopt the definition that gamma rays are the ones produced from nucleus, there is no reference to their energy. Only em radiation from nuclei is called gamma ray in this convention, this does not say that there is no other radiation in the same range where nuclear reactions typically are.

 

[geoelectronics]

And considering that I've shown where this definition is violated, who is at fault here?
That is not the definition of gamma rays. That is the definition of radioactive decay.
It is EM radiation within a loosely defined range of frequency shown in the spectrum of EM radiation.

https://www2.lbl.gov/MicroWorlds/ALSTool/EMSpec/EMSpec2.html
It has nothing to do with how or where it was created.

In the end, what name you give it doesn't affect it one bit. However, the physics that is associated with it does matter, and erroneously thinking that all EM radiation within this range can ONLY be generated via nuclear reaction is patently FALSE!

Think about this: If I have a clump of electrons, and I jiggle it back and forth fast enough, I can generate EM radiation/photons at any frequency that I want, including gamma photons. This, naively, is what we do with those wigglers and undulators insertion devices in FELs and synchrotron centers all over the world. Nowhere in there do I require a radioactive decay.

Zz.

US NRC definition is wrong? Please take it up with them.
yes of course electrons create photons, just not Gamma Ray photons. As I've responded numerous times to your questions, electrons generate X-Rays, Bremsstrahlung Radiation, and cause Characteristic X-Rays in atoms. These are the things we study and measure every day, it is a tool, just like a microscope is a tool. This conversation is ended for lack of relevant response, but if anyone else would pick it up, I can continue the thought.

I think it was this post that mentioned Beta Rays. Beta particles are matter, not rays, but they can produce rays as a secondary byproduct
Rays are photons. Some here seem to think particles are rays and rays are particles. It must just be a difference of dictionary between disciplines, or perhaps someone is not up to date.

While it's not in my wheelhouse, I would have enjoyed sharing with the OP the interactions of an electron beam, at several different level, instead he was insulted and driven away. Like in so many posts I've seen in my few weeks of looking around. This forum seems to be PHD's helping with homework for other PHD's only. My audience starts with the bright 14 year old who has an inquisitive mind and who has a chance at a great career because of that. I came here to get ban answer concerning electron-positron annihilation during the high energy phase. I am already very familiar with the low-energy mode, which can be wrapped up in a short sentence: the electron and
positron must be at rest in the medium before they can annihilate.

To this I add, the positron can be created with much excess kinetic energy, which it must shed by normal electron interactions before it can annihilate an electron. The resultant two photons annihilate creating two opposed 511 keV photons. These are called Annihilation Photons, not X-Rays.

I've been looking for a long time for the high energy equivalence to see if there are still a pair of 511 keV photons as the last result.

For asking this one question I've been screamed at, ridiculed and driven away. But still no reference to a peer reviewed document.

Thank you for your time

George Dowell

 

[ZapperZ]

You just showed that two definitions of the word "gamma radiation" are incompatible.
So on the right edge of this picture there are "Hard X Rays" and "Gamma Rays" with the same wavelength/energy. What is then the difference between these two?
You seem to have this backwards. If you adopt the definition that gamma rays are the ones produced from nucleus, there is no reference to their energy. Only em radiation from nuclei is called gamma ray in this convention, this does not say that there is no other radiation in the same range where nuclear reactions typically are.

This is why I said that the "label", i.e. the name doesn't matter. If I give you a 640 keV photon, and not tell you how it was generated, do you know what to call it? A hard x-ray or a gamma ray? How will it matter in terms of how you deal with it?

I'd call it a Twinkie, because I can. All I care about is what it does, what property it has, and what it can do. Whether I call it a Twinkie, a gamma photon, a hard x-ray photon, or even Pluto, how will that effect any of the physics? Isn't this what really matters in the end?

In my field, we call EM radiation even up to GHz range as "rf", even if, technically, it is not really in the typical rf range. But no one loses sleep over such meaningless label, because all we care about is the actual frequency. Pluto didn't change just because we decided not to categorize it as a planet.

You guys pay way too much attention on the superficial labeling.

Zz.

 

[geoelectronics]

Names/titles/definitions do matter.

"You guys pay way too much attention on the superficial labeling.
Zz."

Thank you for noticing twinkie, it is a trait of scientists or every profession of which we are proud. It comes under the heading of "precision".George Dowell

 

[ZapperZ]

Oh look! NASA is misusing the name "gamma rays" in looking for the range of EM spectrum coming from "black holes and exploding stars"! None of those came from nuclear decay. Tsk, tsk. Someone should tell them that names and labels matter. They should rename that silly telescope because, obviously, even though they are looking for the same frequency range as gamma rays, these can't be given the same name!

Zz.

 

[Dr.AbeNikIanEdL]

This is why I said that the "label", i.e. the name doesn't matter.

I certainly agree with that. You just have to make sure to agree on what label to use for what. This is why I pointed out that there are two different definitions of gamma rays, with none better than the other (without any detail on the application), but which would give different answers to the question "How are gamma rays produced.".

Personally I don't care what definition is used, as long as you tell me which one.

I'd call it a Twinkie, because I can.

But if you want to talk to someone about a Twinkie, you will have to tell him what exactly you mean by it.

All I care about is what it does, what property it has, and what it can do.

But the question here was in particular how it is produced.

Sure, if you are handed photons and are asked to do something it makes more sense to label them according to their properties.

But if I am haded different sources of photons I might be more interested in how these sources work, what mechanism is responsible for photon production within them. I might not care particularly about the exact properties of the photons and "what they can do". In that case I will choose my labels rather according to the properties of the source.

Again, I am not advocating for any of these definitions, just pointing out that they exist and make some sense in particular circumstances.

Oh look! NASA is misusing the name "gamma rays" in looking for the range of EM spectrum coming from "black holes and exploding stars"! None of those came from nuclear decay. Tsk, tsk. Someone should tell them that names and labels matter. They should rename that silly telescope because, obviously, even though they are looking for the same frequency range as gamma rays, these can't be given the same name!

No one is insisting that one of the two definitions is better. The two are just used in different physics communities.

 

[ZapperZ]

I certainly agree with that. You just have to make sure to agree on what label to use for what. This is why I pointed out that there are two different definitions of gamma rays, with none better than the other (without any detail on the application), but which would give different answers to the question "How are gamma rays produced.".

Personally I don't care what definition is used, as long as you tell me which one.
But if you want to talk to someone about a Twinkie, you will have to tell him what exactly you mean by it.
But the question here was in particular how it is produced.

Sure, if you are handed photons and are asked to do something it makes more sense to label them according to their properties.

But if I am haded different sources of photons I might be more interested in how these sources work, what mechanism is responsible for photon production within them. I might not care particularly about the exact properties of the photons and "what they can do". In that case I will choose my labels rather according to the properties of the source.

Again, I am not advocating for any of these definitions, just pointing out that they exist and make some sense in particular circumstances.
No one is insisting that one of the two definitions is better. The two are just used in different physics communities.

I have zero issues with what you wrote here.

However, please note that my original response in this thread was towards @geoelectronics who was insisting that gamma rays must only come from nuclear reactions, and that to claim that a bremsstrahlung process can also generate similar EM radiation is a contradiction to the definition of "gamma rays".

If you believe what you wrote above, then you would also have issues with such a stand.

Zz.

 

[geoelectronics]

Oh look! NASA is misusing the name "gamma rays" in looking for the range of EM spectrum coming from "black holes and exploding stars"! None of those came from nuclear decay. Tsk, tsk. Someone should tell them that names and labels matter. They should rename that silly telescope because, obviously, even though they are looking for the same frequency range as gamma rays, these can't be given the same name!

Zz.

"Oh look! NASA is misusing the name "gamma rays" in looking for the range of EM spectrum coming from "black holes and exploding stars"! None of those came from nuclear decay. Tsk, tsk."

Of course these very much are Gamma Rays. Stars work by nuclear fusion, maybe some fission, lots of neutron activation- all nucleus related.
Definitely near the event horizon, nuclear disintegration. All clearly nuclear, all releasing the very powerful nuclear binding energy also known as mass deficit.

Were not that far apart really.

George Dowell

 

[Dr.AbeNikIanEdL]

I have zero issues with what you wrote here.

Good!

who was insisting that gamma rays must only come from nuclear reactions

Which, with the "source based labelling", is a tautology. This is why I am saying, while labels are fundamentally meaningless, it is important to agree on them.

and that to claim that a bremsstrahlung process can also generate similar EM radiation is a contradiction to the definition of "gamma rays"

I did not find that statement above. Can you point to the relevant post?

 

[ZapperZ]

I did not find that statement above. Can you point to the relevant post?

Post #6.
https://www.physicsforums.com/threads/gamma-and-beta-radiation-in-accelerators.968369/#post-6220902
Zz.

 

[ZapperZ]

"Oh look! NASA is misusing the name "gamma rays" in looking for the range of EM spectrum coming from "black holes and exploding stars"! None of those came from nuclear decay. Tsk, tsk."

Of course these very much are Gamma Rays. Stars work by nuclear fusion, maybe some fission, lots of neutron activation- all nucleus related.
Definitely near the event horizon, nuclear disintegration. All clearly nuclear, all releasing the very powerful nuclear binding energy also known as mass deficit.

Were not that far apart really.

George Dowell

Nope. Now you're just guessing.

Gamma rays from matter falling into black holes is not a nuclear reaction. It is the reverse of bremsstrahlung radiation.

https://www.newscientist.com/article/dn19681-most-powerful-gamma-ray-bursts-linked-to-black-holes/
Those "Jets" are not nuclear reactions.

Zz.

 

[Dr.AbeNikIanEdL]

Post #6.

I don't find a statement about the energies of emissions from nuclear reactions or of bremsstrahlung there, in particular not that they would not overlap.

 

[ZapperZ]

I don't find a statement about the energies of emissions from nuclear reactions or of bremsstrahlung there, in particular not that they would not overlap.

I don't understand what you are saying here. Can you read that post, and then my post following that in response to it to see the issue that I was addressing?

Zz.

 

[Dr.AbeNikIanEdL]

Hm, since we seem to agree on most things maybe there is not a big point in discussing posts by others. All I am saying is that I do not find an issue with post #6, which basically just says that there are these two definitions for what gamma radiation means.

 

[Motore]

I think this description from Wikpedia sums it up best:

Gamma rays and X-rays are both electromagnetic radiation, and since they overlap in the electromagnetic spectrum, the terminology varies between scientific disciplines. In some fields of physics, they are distinguished by their origin: Gamma rays are created by nuclear decay, while in the case of X-rays, the origin is outside the nucleus. In astrophysics, gamma rays are conventionally defined as having photon energies above 100 keV and are the subject of gamma ray astronomy, while radiation below 100 keV is classified as X-rays and is the subject of X-ray astronomy. This convention stems from the early man-made X-rays, which had energies only up to 100 keV, whereas many gamma rays could go to higher energies. A large fraction of astronomical gamma rays are screened by Earth's atmosphere.

https://en.wikipedia.org/wiki/Gamma_ray

 

[geoelectronics]

I think this description from Wikpedia sums it up best:

https://en.wikipedia.org/wiki/Gamma_ray

Wikipedia is a terrible citation for anything scientific.

Here's something you can believe in - black and white:

Photon Emission Products: Am-241
Fraction Energy(MeV)
0.001060 0.033205
0.001793 0.069231
0.024000 0.026345
0.359000 0.059537
0.427000 0.013900

This is the nuclear decay scheme of Am-241 a common household radioisotope.

Those photons listed are a mix of X-Rays and Gamma Rays (by the common definition, not the ancient e-m spectrum charts). Can you say which is which? I can, it's what I do. Their energy tells me everything I need to know.

You all had better hope I'm right because all the world's nuclear power/nuclear research- reactors and nuclear weapons depend on it.
George Dowell