Talk:Gamma ray

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Missing Content[edit]

Section 1, Paragraph 1, Sentence 1, Begins with "This property means that gamma radiation is often used..." Implying that something was discussed before the beginning of the article. Larek (talk) 14:27, 12 June 2009 (UTC)

I would kindly ask, if CERN can give information on the Highest Energy Ever found for a Gamma Quant from Accelerators so far. They have 15 TeV acceleration power. So, what was the most energy rich Gamma quant so far observed? And, are You SURE a 50 TeV Gamma quant can exist, or would it resemble another unknown particle, say, a high energy Neutron, Proton, or Tritium or even heavy ion something accelerated from the sun blast. I would say a high energy ion would NOT catch an electron. so it probably was a heavy ion impact. I think there HAS to be a limit on Gamma energy, forming other particles when energy exceeds. check theory on neutrino pair, quadruplets, +/- muons, e+ e- formation, etc. A that immense gamma quant would pair formate and dissipate. --Wikistallion (talk) 13:16, 8 May 2013 (UTC)

Incorrect information[edit]

Consider that "beta decay" can refer either to negatron or positron decay. If it is negatron decay, an antineutrino is emitted; if it is positron decay, it is a neutrino.

Because a beta decay is accompanied by the emission of a neutrino which also carries energy away, the beta spectrum does not have sharp lines, but instead is a broad peak. Hence from beta decay alone it is not possible to probe the different energy levels found in the nucleus.

should read

Because a beta [negative] decay is accompanied by the emission of a[n anti-]neutrino which also carries energy away, the beta spectrum does not have sharp lines, but instead is a broad peak. Hence from beta decay alone it is not possible to probe the different energy levels found in the nucleus. Bobcat167 (talk) 01:32, 9 January 2011 (UTC)

I gave these comments a headline[edit]

While X-rays are generated by electronic transitions. Gamma-rays are usually more energetic than X-rays, but this is not always the case. For example the 14.4 keV gamma-ray from Co-57 -> Fe-57, is less energetic than many X-rays.

Also, gamma rays can be formed by matter/antimatter interactions, such as electron-positron annihilation.

"Gamma rays from nuclear fallout would probably cause the largest number of casualties in the event of the use of nuclear weapons in a nuclear war"

Irrespective of the case that the large explosion, fireball and heat wave would cause the largest number of immediate casualties, with climate change causing most post-war problems, this is still incorrect: The penetrating power, and small cross section, that makes gamma radiation difficult to shield also means that they are very unlikely to interact with your body. The real danger is vast amounts of alpha and beta emitting dust getting lodged in and around your body and in the foodchain.

Gamma Rays[edit]

I think this page could be moved to "Gamma Rays", the term most often used to refer to this portion of the EM spectrum. Thoughts? I would go with gamma radiation. It's not about rays, neither ray or rays is really a good name. Current name matches X-ray, though.

How are gamma rays detected/observed?[edit]

See title, Pcb21 Pete 08:52, 26 April 2006 (UTC)

Using Cockroach exoskeleton instead of lead to shield against gamma rays[edit]

I've just read that the cockroach exoskeleton helps shield them against alpha, beta, and gamma rays. Could a possible application be - that we can shield people from radiation by using the cockroach exoskeleton instead of lead?

Where did you read that? Cockroach states that their radiation resistance is from the fact that their cells divide less often than humans'. --Ihope127 20:38, 6 June 2006 (UTC)

This is true, I don't know it in greater depth by after nucleur explosions and radiation cockroaches actually still live.

References[edit]

Right now, it is not clear what do references in the end of the article refer to. Why not to migrate to the <ref> system? —Matveims 01:48, 29 May 2006 (UTC)

industrial uses[edit]

Gamma rays also have an industrial application. They are used the same way x-Rays are used to produce images. Weld and other such sensitive items are inspected by bombarding it with gamma rays to create an image of the interior of the item on a piece of film. The most common Isotopes used are: Iridium 192, Cobalt 60, and Cesium 137.

-Devin Snyder

source: http://www.ndt-ed.org/EducationResources/CommunityCollege/Radiography/cc_rad_index.htm —The preceding unsigned comment was added by Myghell (talkcontribs) 07:15, 7 March 2007 (UTC).

Gamma rays are also used to in quarantine treatment as an alternative to heat treatment should it be impracticable (especially on foodstuffs).-- Librarianofages 04:29, 27 March 2007 (UTC)

Health effect[edit]

"The gamma rays are the most dangerous form of radiation emitted by a nuclear explosion because of the difficulty in stopping them. Gamma-rays are not stopped by the skin." This is not quite true - the most dangerous type of radioactive exposure occurs when radioactive gas or dust which is undergoing alpha decay enters the body. The fact that "gamma rays are not stopped by the skin" is actually a good thing in some ways, as gamma rays are far more likely to pass straight through the body without being absorbed than alpha or beta radiation is. Gamma rays are also far less ionising than alpha or beta radiation. Possibly this section needs to be rewritten? Sbiki 14:46, 20 April 2007 (UTC)

I attempted to address these issues briefly, omitting mention of nuclear explosions or saying which radiation is most dangerous, but comparing penetrating/nonpenetrating and internal/external exposure. Perhaps the article on ionizing radiation is the right place to discuss in more detail the full range of biological effects, and how they depend on the intensity, duration, and nature of the radiation, and whether it is from external or internal sources. I also removed the paragraph quoted below, whose second sentence seems to refer to some kind of double-whammy effect whereby gamma exposure exacerbates an already-existing beta burn. If so, I think that's too specialized a topic for this general discussion of gamma ray health effects.

Gamma-rays are not stopped by the skin. They can induce DNA alteration by effect of whole-body gamma-irradiation on localized beta-irradiation-induced skin reactions in mice.[1] CharlesHBennett (talk) 19:30, 1 December 2009 (UTC)

Small copyright infringement[edit]

If anyone has a vested interest in this article and wants to follow this up. It's only small, but text has been copied from this article, verbatim, with no attempt to attribute it. Full details here: http://en.wikipedia.org/wiki/Wikipedia:Mirrors_and_forks/Def#Fallen_Earth_Forums

Question on Final Sentence[edit]

As a recommendation referring to one of the final sentences. In my interpretation more likely than not implies a percentage slightly greater than 50% however in this context a change might be necessary such that the sentence reads: "by an overwhelmingly large margin..." Haven't edited as a consensus on this is necessary.

Whole missing section![edit]

could someone please add a secton on the eenage mutant nija turtles

Veggieburgerfish 19:42, 17 September 2007 (UTC)

after all they are heroes in a half-shell

Actually, a section dedicated to popular references to Gamma Rays wouldn't be that bad. --Antonio.sierra 22:08, 14 October 2007 (UTC)
It should also include the pioneering work of Dr. Bruce Banner.

Misinterpretation of study[edit]

Prior to my edit, the article provided a statistic for comparison, stating that the risk of cancer (other than leukemia) was elevated by 32% for atom bomb survivors. The link that it quoted, however, stated that it was 0.32 (ie, 32%) per Sievert of exposure. Without knowing the average exposure of the atom bomb survivors, this isn't really very useful for comparison, so I've removed it.

Ideally, it should be reinserted with a corrected statistic, based on the radiation dosage received by atom bomb survivors. Unfortunately, the linked article doesn't provide a reference for the statistic, so I can't find the original study to look it up. —Preceding unsigned comment added by 130.155.198.32 (talk) 04:41, 21 December 2007 (UTC)

Wavelength?[edit]

So, in what range of wavelengths on the electromagnetic spectrum do gamma rays fall? --66.51.190.36 (talk) 00:31, 20 February 2008 (UTC)

Less than 10 picometres. Thunderbird2 (talk) 19:16, 20 February 2008 (UTC)
Usually, but the distinction from other kinds of EM radiation is often made depending on the source (gamma rays are produced in an atomic nucleus). The 229Th nucleus has an excited state at a few eV, and its "gamma radiation" has a wavelength of more than 100 nanometers. Icek (talk) 04:02, 10 March 2008 (UTC)
So what is the criterion then? Is it that all EM radiation from an atomic nucleus is considered to be "gamma rays"? Or does it depend on the nature of the transition? Thunderbird2 (talk) 07:09, 10 March 2008 (UTC)
Unfortunately there seem to be different conventions. In physics it is generally the source, and there are possibly even "optical gamma rays". In astronomy it's the wavelength, as this is what determines your method of measurement (and you don't prepare the emitter so you don't know as well as in physics where the radiation was produced). Icek (talk) 21:15, 11 March 2008 (UTC)
Thanks, that helps. By an "optical" gamma ray, do you mean one produced by a sub-atomic interaction that happens to have a visible wavelength? Thunderbird2 (talk) 21:35, 11 March 2008 (UTC)
Yes. Icek (talk) 04:06, 12 March 2008 (UTC)
I disagree with Icek. I'm a physicist, and have done work in gamma-ray spectroscopy. Physicists refer to anything with an energy of >~100 keV as a gamma ray. It's a vague, fuzzy boundary, but the fuzziness extends less than a factor of 2 on either side of 100 keV. If a nucleus emits something with an energy of 10 keV, then people in my field definitely refer to that as an x-ray, not a gamma ray, regardless of the source. The seat-of-the-pants distinction is that x-rays are not very penetrating, and interact mostly via the photoelectric effect, whereas gammas are very penetrating, and interact mostly via Compton scattering (or pair production, at high energies).--76.93.42.50 (talk) 01:33, 18 March 2008 (UTC)
Can either of you quote a source? Could it be that different conventions are used in different fields? Thunderbird2 (talk) 07:08, 18 March 2008 (UTC)
I think I erred when I said that the different definitions are used in physics and astronomy respectively, but there are certainly physicists who call low energy nuclear radiation "gamma": Utter et al. (1999), Reexamination of the Optical Gamma Ray Decay in 229Th, Physical Review Letters 82(3).
Icek (talk) 12:39, 18 March 2008 (UTC)
In any case, the distinction is explained twice -- and redundantly on top of that -- in two distinct sections of the article. It is explained twice. 89.217.12.52 (talk) 00:07, 15 July 2014 (UTC)

Coil wavelength[edit]

This is a legitimate, if somewhat obscure (to this user) term. It keeps turning up here linked to the article dealing with the physical manifestations of a coil. Can any user either add a paragraph here covering the term, or even start a new article? --Old Moonraker (talk) 06:16, 20 May 2008 (UTC)

Gamma rays "stopped" by background light?[edit]

The citation for this mentions it in passing, and I fear it may have been misinterpreted. I am not a physicist, but I was not aware that photons could "stop" each other, only interact by interference. Can anyone with a more solid background comment? Robin S (talk) 23:53, 2 September 2008 (UTC)

Thanks for the prod: this section has been bugging me for a while. Rewritten from the sources, not from knowledge. Might benefit from some oversight by someone who knows what they are talking about! --Old Moonraker (talk) 06:49, 3 September 2008 (UTC)

Dead Link[edit]

FYI: The first link isn't working (404) http://www.rerf.or.jp/eigo/radefx/basickno/whatis.htm Anyone know of an alternative? —Preceding unsigned comment added by RTFArt (talkcontribs) 18:38, 9 October 2008 (UTC)

The Gamma ray burst link to astro.cacltech.edu/~ejb is dead. Alternatives? Or should it just be removed? Varunbhalerao (talk) 17:46, 27 August 2010 (UTC)

Move[edit]

This page needs to be moved to Gamma-ray. Within scientific literature, virtually all usages have the hyphen. I noticed this while preparing Gamma-ray burst for WP:FAC. Jehochman Talk 16:14, 19 December 2008 (UTC)

A common style would be to use the hyphen in the adjective as a compound modifier (e.g. Gamma-ray energies) but not in the noun (e.g. Gamma rays). Alpha particles do not use hyphens when they are nouns. --Rumping (talk) 10:40, 21 January 2009 (UTC)
Yes, you are right. Jehochman Talk 13:02, 21 January 2009 (UTC)

Possible confusion as to source of gamma radiation.[edit]

The article states "'gamma rays are' produced by sub-atomic particle interactions, such as electron-positron annihilation."

Isn't it true that the annihilation (through antimatter reaction) of other subatomic particles in the nucleus could result in said radiation? Beyond that, can't gamma radiation also be caused by superfluous energy in the nucleus after other types of nuclear decay (beyond what the article states, immediately after my included quote)?

It's somewhat confusing that the example is so explicit, without being followed by a greater degree of generalization. —Preceding unsigned comment added by 80.202.73.173 (talk) 18:59, 1 February 2009 (UTC)

In my experience in both physics and radiation safety, electron-positron annihilation produces two 512keV x-rays, not gammas. I was taught that the ONLY difference between x and gamma rays is the source; x and gammas of the same energy are otherwise indistinguishable. Photons emitted from the nucleus are gammas, all else are x-rays. Yes, they have slightly different energy ranges, but for the most part the two ranges overlap. Also, all radioactive decays result in a daughter element that is different to the parent (i.e. the daughter ends up with a different number of protons in the nucleus). Since gamma emission alone can not change the number of protons, it means that an atom that emits gammas only is not undergoing radioactive decay, just a de-excitation of the nucleus. Gamma emission provides a means whereby an excited nucleus can give off a little energy (little, relative to the much larger mass-energy released through particle emission) without undergoing radioactive decay. —Preceding unsigned comment added by 142.179.55.107 (talk) 16:44, 12 March 2009 (UTC)

Cobalt 60 link needs to be fixed[edit]

Go ahead and click on the Cobalt 60 link. Whoever wrote this page put in the link destination as "Cobalt_60" instead of "Cobalt-60", note the underscore instead of dash, which linked it to a rock group. And because these authors consider themselves SUCH experts epitomizing the pinnacle of flawlessness, they made it impossible to edit the Gamma Ray page. Way to GO, guys! You kept me from hijacking your precious work by correcting your mistakes. You should be proud. SO. Some users are given "big cheese" status obviously, able to modify certain pages that are off limits to ordinary dolts who they think would screw it up. Who do I have to petition to get the big cheese status for myself? Sandorman (talk) 15:20, 1 March 2009 (UTC)

I fixed it for you; stick around for a few more days and do a few more edits and it will let you in to edit gamma ray. Semiprotected articles need the editor to have made 10 edits first. Do you know anything about that "gamma ray window"? Graeme Bartlett (talk) 20:37, 1 March 2009 (UTC)
That entire "gamma ray window" sentence was spurious. ("The most biological damaging forms of gamma radiation occur in the gamma ray window, between 3 and 10 MeV. See cobalt 60.") It was completely unsupported and very unverifiable (I tried hard!), so I removed it. It was added 2009-02-25 by IP-address user 68.202.9.8 who has only 4 edits, some of which were wacky. Unfortunately, many online posts have casually quoted that sentence since then, simply because it was on Wikipedia and therefore has to be true. Ugh. It is a WikiMyth! No one corrected the bad grammar in the article, but it was corrected in various ways when copied and re-posted elsewhere. Some added smart-sounding but hokey details. ("Those below 3.0 MeV are NOT very harmful. They have poor penetrating power and do not deposit much energy. Those higher energy gamma rays of greater than 10 MeV are NOT very harmful because the body is relatively transparent to them.") One definition for "gamma ray window" that fits that sentence would be a range of energies or wavelengths at which the attenuation coefficient of matter is especially low, similar to the infrared window for IR radiation, or the water window for x-rays. There actually is such a range, at around 4MeV, where most elements show a minimum in their mass attenuation coefficient for photons (x-rays and gamma rays). The problems are: 1) No one else calls that phenomenon a "gamma ray window". 2) The local minimum does not mean that 3-to-10MeV rays are more damaging; if anything, it would make them less damaging to life. 3) Official guidelines deem all x-ray and gamma radiation to be equivalent in biological activity. Similar measured doses of photons do similar damage, independent of the photon energy. No one says otherwise. 4) 3-to-10MeV radiation might have an easier time getting through shielding, but the subject is what that radiation does, not how hard it might be to shield. 5) The increase in attenuation above 10MeV is not as dramatic as the fall to the minimum. Thus, energies above 10MeV are not very dissimilar to energies inside the "window". 6) Most online mentions of "gamma ray window" refer to astronomers' ability to "see" gamma radiation from outer space. The window is said to be "open" when detection instruments are online, and "closed" when they are offline. The width of the gamma window is the range of energies which can be detected. 7) Some online mentions of "gamma ray window" mean a physical aperture through which gamma rays enter an instrument. 8) A "gamma ray window" could refer to the 3-to-10MeV range of extraterrestrial gamma rays which might pass more easily through the earth's atmospheric shielding and interstellar dust and gas. Thus 3-to-10MeV gamma rays could be easier to observe using ground-based instruments (not possible), and 3-to-10MeV gamma rays could be more able to reach earth from distant gamma-ray bursts and kill us. This might or might not be true, and the notion of which ranges of extraterrestrial radiation could injure life on Earth really does not make that kind of radiation "the most damaging". -A876 (talk) 05:33, 12 September 2013 (UTC)
If you look around the web you'll find a lot of WikiMyth! I've even corrected the source Wiki only to ponder the thousands of casual copies all over the web !! 89.217.12.52 (talk) 00:14, 15 July 2014 (UTC)
To further comment on your excellent and crisply argued research: "which ranges of extraterrestrial radiation could injure life on Earth" -- to put a sharper point on it "which ranges of rare, catastrophic extraterrestrial radiation could injure life on Earth" ... 89.217.12.52 (talk) 00:23, 15 July 2014 (UTC)

Layout Problem[edit]

I'm running the beta view of Wikipedia and the Nuclear physics side box is covering up text in the intro paragraph. I'm unfamiliar with editing layout problems like this and am not sure if the problem is with this article in particular or if it is a problem with the beta version itself so someone more experienced may want to look into this. —Preceding unsigned comment added by Nyr56 (talkcontribs) 02:55, 16 November 2009 (UTC)

More Layout[edit]

I find the layout near the end confusing, with a section title "Health Effects" and no subsections, then a following section, "Uses" with subsections Body Response and Risk Assessments, both of which refer to health effects. The first sentence in "uses" refers to irradiation, then it moves on to radiation treatment and imaging, and the section ends with container scanning. This is followed by a subsection back on irradiation/health. There seem to be a number of regular editors here and I'm a first-time visitor, so maybe one of you could look at those sections with a fresh view? Robsavoie (talk) 22:40, 27 December 2009 (UTC)

Unit prefix[edit]

In the risk assessment section it seems silly to use the cs- prefix for the dose. Why say 500 cSv and not just 5 Sv for example? It seems more logical and straightforward in this section to not use the cs- prefix? Abiermans (talk) 22:48, 9 December 2009 (UTC)

What is the shortest wavelength discovered/Measured Gamma ray?[edit]

What is the shortest wavelength discovered/Measured Gamma ray? --Nevit (talk) 22:15, 14 March 2010 (UTC)

A tentative 7 to 50 TeV[edit]

Check out the page on Gamma ray astronomy! Seems like the highest energy photon observed so far came from The Crab Nebula and was around 50 TeV in energy...I'll let you work out the Wavelength [2]

Energy in Joules= [Planck's constant x Speed of light]/wavelength in metres. Rearrange the equation. [3]

So 2.4797 x 10^-20 m was the wavelength, DON'T TRUST ME, DOUBLE CHECK. I wonder if photons with wavelength lower than the Planck Length scale(1.616252(81)×10−35 m) could be used like a microscope or Electron microscope to explore the Planck length quantum scale of the cosmos? I'm sure it would reveal more than just tiny quantum foam etc, perhaps even BoundaryLayer waz here vandalism all over the Universe?

[4] Even more energetic PeV gammma rays mentioned.

Although unlikely to be A Photon Ultra-high-energy cosmic ray 50 Joules of energy gives you a photon wavelength of 3.9729e-27 m, which would work for my 'microscope' needs.

[5]

If anyone finds a reference to a higher energy photon being observed, please let me know! --Boundarylayer (talk)

Energy phrasing[edit]

FTA: Gamma rays from radioactive decay commonly have energies of a few hundred keV, and are almost always less than 10 MeV in energy. This sentence is very confusing. Could someone please re-phrase? —Preceding unsigned comment added by 212.71.114.220 (talk) 08:46, 25 October 2010 (UTC)

Rephrased. Materialscientist (talk) 08:55, 25 October 2010 (UTC)

A question on gamma decay[edit]

When the daughter nucleus is in an excited state we mean that one of its electrons is on a higher floor, right? The nucleus itself (protons, neutrons, quarks) can't be in an excited stage, right? So for example men cobalt 27 60 becomes nickel 28 60 it gets a new set of electron floors (energy levels) and therefore a few electrons may be on a to high floor given the new more strongly positively charged nucleus, so they jump down and throw out a photon?--JR, 11:57, 24 May 2007 (UTC)

Yes, nucleons (protons, neutrons) can be in an excited state. The photons emitted by electron transitions are by definition not gamma rays. All nuclear radiation is by definition due to transitions in the state of the nucleus, not the electrons. Rwflammang 14:43, 29 August 2007 (UTC)

Gamma decay is a common term[edit]

For example: [1]. I'm reverting a new IP editor who seems to think it's improper. SBHarris 00:01, 1 March 2010 (UTC)

What is gamma decay[edit]

Gamma decay redirects here, and the article freely uses the term, but it is never explained or defined what gamma decay is.  --Lambiam 23:50, 10 February 2011 (UTC)

Gamma decay is the type of radioactive decay of an excited state of a nucleus, where a gamma ray is the thing that is emitted. I'll see if I can make sure it is used in a sentence in the article somewhere.SBHarris 04:05, 11 February 2011 (UTC)

Measurement units[edit]

Do we really have to use centisieverts (cSv) as a unit? They are exactly the same as a rem after all. Otherwise how about just converting them to mSv or Sv?

Should wavelength be included[edit]

I think the wavelengths should be either preceded by 'in a vacuum' or that stated at the beginning of the article eg. 'This article refers to gamma rays in a vacuum' as their wavelengths will be significantly changed by the speed of the light, reduced in glass or water whereas the frequency is constant. Please comment below to say whether this going to be considered or implemented.

When wavelengths are given without qualification, it's assumed that they are in vacuum. Furthermore, the effect of common media on the wavelength of X-rays and gamma rays is so small that it doesn't effect wavelength until the 5th significant digit, which means the fuzzy wavelength boundaries given in this article are the same in water as in vacuum. Example, the wavelength of the 0.8 Angstrom Co-57 gammas in Lucite plastic is the same as in vacuum, less 1.3 parts PER MILLION (which is how much the refractive index is more than vacuum). [2] In short, don't worry about it. SBHarris 19:28, 21 April 2011 (UTC)

Thanks K9 K9doggy (talk) 19:45, 26 April 2011 (UTC)

Is there a typo in this article? No specialist.[edit]

Right over at Risk Assessment (http://en.wikipedia.org/wiki/Gamma_ray#Risk_assessment), the article poses: "By comparison, the radiation dose from chest radiography is a fraction of the annual naturally occurring background radiation dose,[15] and the dose from fluoroscopy of the stomach is, at most, 50 mSv on the skin of the back."

Now, whether it is significant that 50mSv would be exposed to only the skin of the back, or that 50 mSv hits you, I don't know. Before, however, the article states that "the average total amount of radiation received in one year per inhabitant in the USA is 3.6 mSv.[13]".

My question now is: is this 50 mSv a typo? If not, the construction of the whole first quotation, especially with the mentioning of "fraction of the annual", indicates that the total radiation dose of fluoroscopy too should be insignificant. I kinda find one radiation dose worth roughly 14 years of USA exposure rather significant, so, shouldn't this be made clear.

Any specialists? I'm just reading up, having a question.

Tonijnenlul (talk) 10:54, 22 June 2011 (UTC)

I don't see any reason to believe that's a typo. Those numbers are consistent with the info in the article Background radiation and seem quite reasonable to me. Dauto (talk) 20:08, 23 June 2011 (UTC)
Yes. Fluoroscopy really does deliver huge amounts of radiation. 50 mSv should be compared to 5 to 8 mSv for a chest CT, but only 0.06 mSv for a chest X-ray (two views). Which in turn compares with background of 3.6 mSv. I've fixed up the fluoroscopy section so it doesn't sound like it's a small dose (it's not). I'll add the CT numbers as it's what people are more familiar with (very few people will every have fluoroscopy). SBHarris 01:11, 24 June 2011 (UTC)

This is a mess.[edit]

So in the first section, it says that in the past, the distinction between gamma and x rays was at an arbitrary wavelength (or the corresponding frequency). The second section opens up by saying that, in the past, the distinction was based on the energy level. That is directly contradictory to what the first section says.

No, they are the same. Photon energy determines photon wavelength and frequency. E = hf and E = hc/lambda. SBHarris 01:18, 22 June 2013 (UTC)

The other big problem, is that if you treat the gamma radiation as being an electromagnetic wave rather than a particle, the energy level of the gamma ray depends on its duration. To make this quite simple, the sunbeams hitting your solar panel convey twice as much energy in two hours, as they do in one hour. It is the same for the gamma rays. To talk of the energy of an electromagnetic radiation without a duration for it makes no sense. That is why the amount of solar radiation arriving at your solar panel is expressed in watts not joules. If there is a good explanation why the power of a gamma ray is expressed as energy, then someone should include that.Eregli bob (talk) 01:07, 25 March 2012 (UTC)

You are mixing up energy of an individual gamma particle and radiation energy (one way to express it is take a product of particle energy and the number of particles hitting a panel during a certain period). Materialscientist (talk) 01:50, 25 March 2012 (UTC)

I also take exception with the opening sentence: " refers to electromagnetic radiation of high frequency and therefore high energy per photon."... Energy and Frequency are two differing attributes. You can have high energy and low frequency and vice versa... What is going on here? If it isn't talking about energy- energy, perhaps it should be clear? Dkelly1966 (talk) 01:04, 22 June 2013 (UTC)

"High energy PER PHOTON". This is a basic quantum mechanical relationship. Energy and frequency in quantum mechanics are the same thing (they literally differ only by the constant factor h, which is Planck's constant). In a beam of radiation you cannot have less energy than E = hf. You can have more energy than this minimum (any amount) but only by having more than one hf (photon), so that E(total) = n (hf). Gamma rays are made one photon at a time. Each nucleus makes a photon. The frequency of the photon hf is determined by the energy available to make it. Please read photoelectric effect. SBHarris 01:18, 22 June 2013 (UTC)

Lots of duplication in this article[edit]

The first half of this article needs clean up. The last paragraph in the intro is almost repeated word for word in the section called "General Characteristics".

It is also repeated twice that "the wavelengths characteristic of radioactive gamma ray sources vs. other types, now completely overlap. Thus, gamma rays are now usually distinguished by their origin". We don't need to mention this in two different sections. Cshay (talk) 04:12, 14 November 2012 (UTC)

Agreed. 89.217.12.52 (talk)

Needs a history section.[edit]

I was trying to find out who discovered gamma rays and when... but no history section? SteveBaker (talk) 18:12, 10 February 2008 (UTC)

Discovered and investigated by French physicist, Paul Villard, around 1900. He established some of its properties, correctly noting its similarity to X-rays. Rutherford was probably the first to actually call them gamma rays, and to understand that they were high-energy photons. Read some more here. I will add a paragraph when I get some free time. Cragwolf (talk) 02:15, 11 February 2008 (UTC)

Discovery[edit]

These edits have replaced footnoted, verifiable material with a new version of history without citations which I am unable to confirm. It's true that Bequerel discovered natural radioactivity years before Villard's experiment, and perhaps his films were darkened in part by radium gamma? But it doesn't sound like it: uranium is an alpha/beta emitter, and according to this source Becquerel even denied Villard's experimental results and conclusions. So although it may be useful to mention Becquerel, I think we should reinstate Villard and distinguish carefully what these two men's contributions were.--Yannick (talk) 16:37, 8 December 2012 (UTC)

Question on magnetic fields[edit]

The article mentions that the gamma rays were thought to be massive particles, but they were in fact massless EM radiation, as demonstrated by the fcat that they did not get deflected by magnetic fields. However, surely this is simply a sign that they are not charged/ have no magnetic moment, and nothing to do with their mass, or wave/particle character? 80.254.147.172 (talk) 07:58, 27 August 2013 (UTC)

Correct. Gamma rays were only identified definitely as photons in 1914, when they were observed to be reflected from crystal surfaces. source. — Reatlas (talk) 12:59, 27 August 2013 (UTC)