What is Gamma: Definition and 711 Discussions

Gamma (uppercase Γ, lowercase γ; Greek: γάμμα gámma) is the third letter of the Greek alphabet. In the system of Greek numerals it has a value of 3. In Ancient Greek, the letter gamma represented a voiced velar stop /ɡ/. In Modern Greek, this letter represents either a voiced velar fricative or a voiced palatal fricative.
In the International Phonetic Alphabet and other modern Latin-alphabet based phonetic notations, it represents the voiced velar fricative.

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  1. S

    I Is there such a thing as a gamma particle?

    OK, I understand that a gamma ray is just an electromagnetic wave, and so a gamma particle could be a photon, but somehow I think that the author here is not being that sophisticated: https://www.theatlantic.com/magazine/archive/2019/09/why-are-washing-machines-learning-to-play-the-harp/594706
  2. filip97

    A Why Spinors Are Irreducible if Gamma-Traceless: Explained

    I read this question https://physics.stackexchange.com/questions/95970/under-what-conditions-is-a-vector-spinor-gamma-trace-free . Also I read Sexl and Urbantke book about groups. But I don't understand why spinors is irreducible if these are gamma-tracelees. Also I read many papers about...
  3. pallab

    I Dirac's Gamma Matrices: What Are They & Do They Have Many Forms?

    what are Dirac's gamma matrices . especially , does it have many forms?
  4. K

    Relating the Gamma Constant to the absorbed dose

    It is unclear from my text. Can you use the gamma constant to find the absorbed dose for a point source of photons?
  5. D

    How short can electromagnetic radiation become? Shorter than gamma rays?

    is there some physical limit on the wavelength of electromagnetic radiation? Can there be radiation shorter than gamma rays?
  6. C

    I The Sun's excess gamma rays and strange dips

    Any theory what could be causing the excess gamma ray and the strange dips in the sun? https://www.quantamagazine.org/gamma-ray-data-reveal-surprises-about-the-sun-20190501/ "A decade’s worth of telescope observations of the sun have revealed a startling mystery: Gamma rays, the highest...
  7. wildonion

    A Generate a gamma curve with values

    I would like to use a known area and values on the x-axis to generate a gamma curve to obtain y values. Please point me in the right direction. A = 0.07 m^2 Values on x axis 0.5 0.6 0.7 0.8 0.9 1.0 1.2 1.3 1.4 1.5 1.6 1.7 Thank you!
  8. TheBigDig

    Energy of Two Gamma Rays Produced by Pion Decay

    So I worked out the first part and obtained ##E_1 = 478.8MeV##, ##E_2 = 459.4MeV## and ##p = 0.49 MeV/c## but I can't quite wrap my head around the second part. Normally, I'd use the equation for s but I'm confused since I don't know the angle between the gamma rays.
  9. R

    How Do You Solve a Complex Gamma Distribution Problem Involving System Failures?

    I'm lost. First one was easy to calculate, second one is harder. I have: P{a fails before 2 yrs} = .323325 P{b fails before 2 yrds} = .90844 P{system doesn't fail for 2 years or longer} = .062 P{system does fail before 2 years} = .938 P{A and B fail before 2 yrs} = .29372 P{before 2 years A...
  10. S

    I Does a solar eclipse gamma of 0 mean eclipse goes through 90° altitude?

    This is my understanding.
  11. Baroo

    I Gamma and beta radiation in accelerators?

    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?
  12. A

    I Gamma in Brans-Dicke framework

    I take an empirical relation of Φ=Φ0(a/a0)n where n=-(dG/dt)/GH ,present study shows n is negative ,implies that G increases with time And using this fact and taking a scale factor of the form sinh(t) ,evaluated ϒ and then plot it with respect to t and got the above figure which is consistent...
  13. I

    Spacetime Invariant interval and gamma

    I am revisiting the invariant interval spacetime issue , as explained in the book Spacetime Physics by E.F. Taylor and A. Wheeler. The explanation is clear and the invariant interval is correct, based on the data given and this is the whole point I am making, as explained below. In a...
  14. S

    B Double Slit Experiment with Gamma Rays

    Hi I was wondering what would happen if you use Gamma Rays in a double slit experiment. Would you see the same interference pattern?
  15. mesa

    Looking for excited state gamma emission data on everything?

    Hey guys, I am looking for a database on gamma emission from the first few excited states of known isotopes for a piece of software we are putting together. Any format is fine. Thanks!
  16. KangOfCanada

    A How do Fusion/Fission Gamma Rays Compare?

    My concerns are all about how much shielding would be needed for a nuclear reactor. Would aneutronic He3-He3 fusion produce less energetic photons than fission to be more easily used in more mobile reactors? Obviously very few neutrons are made in this reaction so that leaves the high energy...
  17. Amanuel

    How to calculate the energy in gamma photons

    how do I calculate the energy of to photons moving in the opposite direction. starting from the same origin.
  18. B

    A Residues of gamma functions

    Hi members, I have a problem with the computation of residues involve the gamma functions. (see attached Pdf file) Can you show me for the first residue with the arrows, or give a hint or a link. Thank you
  19. S

    I Gamma absorption at increasing energy levels

    Which are main absorption modes of matter for gamma rays under about 500 MeV? And how strong is the absorption? For low energies (under 20 MeV) the mechanisms are: 1) Photoelectric absorption - all energies from eV range onwards 2) Compton scattering - all energies enough to displace the...
  20. S

    I Gamma Decay (Electric and Magnetic Transitions)

    I'm trying to understand electric and magnetic transitions in gamma decay a bit more intuitively than i currently understand but I'm having a really hard time doing so When the nucleus is coupling to the electric field of the photon we call it an electric decay and the parity is: (-1)L When...
  21. D

    I What is the gamma factor in a particle's rest frame?

    Hi. If the 4-momentum in SR is given by p = m γ(v) ( 1 , v ) then in the rest frame of a particle the 4-momentum is ( m , 0 , 0 , 0 ) using c=1 units. This uses the fact that because v = 0 then γ(v) = 1. I'm confused about this last sentence. The gamma factor is used for the relative velocity...
  22. caters

    High dose gamma ray exposure vs Low dose gamma ray exposure

    I found out that high dose gamma ray exposure is actually easier for the body to repair than low dose gamma ray exposure. At first this made 0 sense to me as higher dose means you are exposed to more gamma rays per second and thus more damage is done. But now that I think about it, I think that...
  23. M

    MHB Gamma function is convergent and continuous

    Hey! :o I want to show that the Gamma function converges and is continuous for $x>0$. I have done the following: The Gamma function is the integral \begin{equation*}\Gamma (x)=\int_0^{\infty}t^{x-1}e^{-t}\, dt\end{equation*} Let $x>0$. It holds that...
  24. G

    I X-ray tube to gamma tube question

    A recent post here made me think about this so I wanted to ask. Now a x ray tube working principle is basically the opposite of the photoelectric effect, here instead of photons electrons strike a metal target to deposit their energy which is released as heat (IR radiation) and photons. So the...
  25. A

    I Latest Gamma Ray Burst Experimental results

    with regards to this https://arxiv.org/abs/1103.5626 "Gamma ray burst delay times probe the geometry of momentum space" May we have updates of the latest experiment results along the line of Smolin 2011 idea concerning gamma ray burst delay times that can test if momentum space is curved?
  26. howabout1337

    I Showing relationship between zeta and gamma

    How can I show that ##\int_0^\infty e^{-nt}\,t^{x-1}\,dt=\Gamma(x)\,n^{-x}\,## for ##x \geq 1\,##?
  27. O

    I U-235 thermal neutron capture gamma ray

    Hi, When U-235 captures a neutron, it may end up with a fission reaction or an excited U-236 isotope. This U-236 emits gamma rays as it goes to its ground state. What I want to learn is that how much is the contribution of these gamma rays' energy to overall fission energy. I checked the...
  28. K

    Gamma matrices in higher (even) dimensions

    Homework Statement I define the gamma matrices in this following representation: \begin{align*} \gamma^{0}=\begin{pmatrix} \,\,0 & \mathbb{1}_{2}\,\,\\ \,\,\mathbb{1}_{2} & 0\,\, \end{pmatrix},\qquad \gamma^{i}=\begin{pmatrix} \,\,0 &\sigma^{i}\,\,\\ \,\,-\sigma^{i}...
  29. H

    Two parallel opposed Co-60 Gamma Ray beams in Excel

    Hi everyone, I have this question about POP. Assume a patient separation of 20cm. Using data for 6MV , FS 10x10 cm, plot the depth dose for one beam at 2 cm intervals. Include on your plot the dose at dmax and the dose at 20-dmax. On the same graph repeat this for the opposed beam. Now plot the...
  30. C

    A Proving Gamma 5 Anticommutes with Gamma Matrices

    "It is easily shown" that the gamma 5 matrix anticommutes with the four gamma matrices. Can someone tell me how or provide a link to such proof?
  31. A

    Linear attenuation coefficient for gamma ray attenuation

    Homework Statement I have data for the count rate (of gamma rays) against the thickness of various materials (Al, Pb, Fe etc...). I want to work out the linear attenuation coefficient. Can I do this by plotting the natural log of count rate against thickness? I don't have values for...
  32. G

    Gamma ray irradiation and a shielded chamber question

    Hi I was reading an article about a gamma ray materials testing camera built into one of the research reactors that worked in my country a while ago. Now I have a few questions regarding some of the issues the article wasn't informing about. It says that they built a special enclosed and...
  33. L

    A Gamma function, Bessel function

    I have question regarding gamma function. It is concerning ##\Gamma## function of negative integer arguments. Is it ##\Gamma(-1)=\infty## or ##\displaystyle \lim_{x \to -1}\Gamma(x)=\infty##? So is it ##\Gamma(-1)## defined or it is ##\infty##? This question is mainly because of definition of...
  34. N

    E(X^r) from Weibull Distribution is equal to Gamma Fn

    Homework Statement I have f(x) = BxB-1e-x^B I need to show that E(Xr) = Ƭ(Gamma)(R/B + 1) Homework Equations I know that E(Xr) = f(x) The Attempt at a Solution Attempt at part of solution I started by saying let u = xB so du = BxB-1dx Can I say then that if u = xB, then Xr = ur/B...
  35. Milsomonk

    Commutator of the Dirac Hamiltonian and gamma 5

    Homework Statement Show that in the chiral (massless) limit, Gamma 5 commutes with the Dirac Hamiltonian in the presence of an electromagnetic field. Homework EquationsThe Attempt at a Solution My first question is whether my Dirac Hamiltonian looks correct, I constructed it by separating the...
  36. Sebastiaan

    A How to calculate the energy of Gamma rays in fusion

    Lets say you have your basic fusion reaction D + H → He3 + γ + 5.49 MeV Now exactly how much of the energy is carried away by the gamma ray and how much by the Alfa particle ?
  37. J

    Proof for Γ(p+1/2) using Double Factorial and nΓ(n)

    Homework Statement Prove that for a positive integer, p: https://www.physicsforums.com/posts/5859454/I've tried this to little avail for the better part of an hour - I know there's a double factorial somewhere down the line but I've been unable to expand for the correct expression in terms of...
  38. L

    A Gamma function convergence of an integral

    ##\Gamma(x)=\int^{\infty}_0 t^{x-1}e^{-t}dt## converge for ##x>0##. But it also converge for negative noninteger values. However many authors do not discuss that. Could you explain how do examine convergence for negative values of ##x##.
  39. Elvis 123456789

    Collision of alpha with Be -> C + gamma

    Homework Statement Before the discovery of the neutron, it was proposed that the penetrating radiation produced when beryllium was bombarded with alpha particles consisted of high-energy &gamma rays (up to 50 MeV) produced in reactions such as α + 9Be --> 13C + γ a.) Calculate the Q value for...
  40. binbagsss

    Gamma Function Identities

    Homework Statement To show: Homework Equations The Attempt at a Solution To be honest, I'm pretty stuck. I could try to use the third identity: ##\Gamma(-k+\frac{1}{2})=\frac{2\sqrt{\pi}}{2^{-2k}}\frac{\Gamma(-2k)}{\Gamma(-k)} ## but this doesn't really seem to get me anywhere. I...
  41. ORF

    Gamma detection -- Cherenkov radiation in gamma-scintillator interaction

    Hello During a simulation of light in gamma-scintillator interaction, it seems that there are a lot of Cerenkov photons. I don't know their contribution to the final intensity (it will need a long time to compute it). The textbooks usually say that the gamma ray will produce secondary...
  42. B

    Dual spinor and gamma matrices

    Here it is a simple problem which is giving me an headache,Recall from class that in order to build an invariant out of spinors we had to introduce a somewhat unexpected form for the dual spinor, i.e. ߰ψ = ψ†⋅γ0 Then showing that ߰ is invariant depends on the result that (ei/4⋅σμν⋅ωμν)† ⋅γ0 =...
  43. G

    I Gamma radiation, photon energies and wavelength question

    I haven't though about this from such a perspective but today while reading wikipedia (yes yes not the best source) I got confused, now the "eV" is said to measure the energy gained by an electron between a potential difference of 1V. I assume particle physicists use this measurement because its...
  44. Z

    I Cs-137 Experiment: Effects of Heavy Metal Shielding on Radiation Levels

    Hey guys, I am currently running an experiment with Cs-137 multiple sources ranging from 1 to 10 uCi, i have a lead pig with a Cs-137 source at the top and a 1/4" small tunnel drilled through the 2" thick slab inside the pig is the Gieger counter, Using various heavy metals as a shield i seem to...
  45. L

    I Havil's book "Gamma" page 57, formula

    Where does the 1 in the last line come from? Thank you!
  46. R

    Could there be life that thrives in gamma rays?

    I am not sure if this is entirely correct, but first I am going to say that life on Earth mostly thrives in the visible range of the electromagnetic spectrum, and perhaps some infrared and ultraviolet (for some creatures), because it is the frequency range that they were the most exposed to...
  47. Adam Rabe

    Percentage transmittance gamma ray through lead

    Homework Statement Homework Equations I = Io e^-ux The Attempt at a Solution 0.75 = 1 * e^-u1 using algebra... u =2.117 I = 1 * e^-2.117*3 I = 0.00175 Answer is apparently 42.2. Can someone tell me where i went wrong? Thanks for any help as always
  48. S

    What is the energy of the most intense gamma peak?

    Handgun ammunition contains Ba and Sb compounds. Firing a handgun leaves residues of these elements in microgram quantities on the back of ones hand. Such quantities are 1000 times above the detection threshold for neutron activation analysis for Ba and Sb. Assuming a swab is taken from the back...
  49. MAGNIBORO

    I Why are there no other gamma functions?

    hi, i was thinking that every function that satisfies the conditions $$f(0)=1$$ $$f(n+1)=(n+1)f(n)$$ could be a generalization of the factorial function, and why the gamma function is the only function that complies with this conditions? I mean why don't exist other functions, or functions...
  50. Daniel Petka

    B Energy of Gamma Ray Photon with Wavelength h

    What would be the energy (eV) of a gamma ray photon with the wavelength h (Planck's length)?
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