What is Gamma: Definition and 710 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. Marina123456

    To simulate the interaction of gamma photons with only oxygen (O) atom

    Hello! i need help in such case. I want to simulate the interaction of gamma photons with only oxygen (O) atoms in MCNP, while am using the material card for silicon dioxide (SiO2). Which card shall I use to get the photon interacted with only the oxygen component separately. Thanks for help.
  2. S

    Gamma Ray Shielding -- How much is enough?

    If Shielding is required for gamma ray flux of 1e23 (let say E=1 Mev). As Shielding cannot fully attenuate flux to zero, how much percentage is technically recommended for shielding of above flux?. So far as I know shield thickness is considered to minimise dose/flux Upto 1/10 of its...
  3. Graham87

    Troubleshooting Nuclear Reactions: Decay, Gamma Rays & More

    The problem comes with solutions. However, I dont get the 3 steps in the solutions. Why do they calculate decay for 120min in step 3? And why is only the daughter nuclide relevant and no granddaughter? There might be something lacking in my knowledge about nuclear reactions. Also, I don't know...
  4. R

    Phonon Density of States (PDOS) at Gamma Point

    Hello everyone! I'm trying to replicate phonon density of states (PHDOS) diagrams for some solids using Quantum Espresso. The usual way I do it is the following one: scf calculation at minima (pw.x) Calculation of dynamical matrix in reciprocal space with nq=1 or 2 (ph.x) Calculation of...
  5. eneacasucci

    I Gamma radiation decay intensity (IAEA nuclide chart)

    I was looking at the gamma radiation data from IAEA's website: (https://www-nds.iaea.org/relnsd/vcharthtml/VChartHTML.html) and was confused by the absolute intensity listed in the page. I Googled it and it seems to be the probability of emission but why it doesn't add up to 100%? For example...
  6. B

    B Gamma Ray Burst / Jet Questions

    The 1st photo is a Google image of a Gamma ray Burst in space, the image in the other photo is being emitted from a device I am playing around with. I am just wondering what is the cause of or what dictates the behavior of actual Gamma Ray Bursts in space vs whatever light patters are in the...
  7. James1238765

    A Gamma matrices and Gell-Mann's I - Y categorization

    As there was quite rightly some criticism earlier about not following proper theory, I will first demonstrate what I have understood of the gamma matrices of SU(3). There are 8 gamma matrices that together generate the SU(3) group used in QCD. Gell-Mann used only 2, ##\gamma_3## and...
  8. osaplabs_sja

    A Can any thin materials protect a Mars spacecraft from gamma rays?

    Astronauts heading towards Mars (and hopefully return) will need protection against the harmful effects of gamma rays in space for this long trip. Apparently, much shorter trips have not caused enough bodily harm to be of much concern. However, a 6-month or longer trip might be a real problem. I...
  9. nomadreid

    I Applications of complex gamma (or beta) functions in physics?

    An example of physical applications for the gamma (or beta) function(s) is http://sces.phys.utk.edu/~moreo/mm08/Riddi.pdf (I refer to the beta function related to the gamma function, not the other functions with this name) The applications in Wikipedia...
  10. T

    I Closed Form for Complex Gamma Function

    Hey all, I was wondering if there was an equivalent closed form expression for ##\Gamma(\frac{1}{2}+ib)## where ##b## is a real number. I came across the following answer...
  11. benorin

    Relief of Complex Gamma Fcn — was this hand drawn?

    This pic is from an older text called Tables of Higher Functions (interestingly both in German first then English second) that I jumped at buying from some niche bookstore for $40. Was this hand drawn? I think I’ve seen was it that mathegraphix or something like that linked by @fresh_42...
  12. G

    Model Fuel Assembly w/ Gamma Source: Solving a Sampling Problem

    Hi everyone, I'm making a fuel assembly model and I would like to have a cylindrical gamma source on each fuel rod to measure the decay heat of a fuel assembly but I'm struggling to define the source since it is in a repeated structure. This is the geometry of my model: Level 2 : cells 1, 2 3...
  13. mesa

    Looking for information on gamma light sources

    Hello, I am looking for something a bit out of my wheelhouse today, gamma light sources (10 MeV or higher on the max energy threshold). Does anyone here have experience or more information on these machines? Are they typically electron accelerators utilizing a tungsten or tantalum target? I am...
  14. benorin

    I Functions.wolfram.com accepted and published my formula for Gamma Fn

    I sent them an email about a week or so ago with the images of the following from the solutions to exercises section 1 of my Insight Article A Path to Fractional Integral Representations of Some Special Functions: 1.9) Use partial fraction decomposition and the Euler limit definition of the...
  15. U

    Adiabatic expansion with temperature-dependent gamma

    The statement does not say whether the process is reversible or not, but I suppose the only way to solve the problem is by thinking it actually is. I tried using the formula for reversible adiabatic processes, i.e. PVγ = constant. First, I calculated the initial volume with the ideal gas law...
  16. F

    I Gamma - A Minkowski Spacetime Diagram Generator

    Gamma is a Minkowski spacetime diagram generator. I probably started this project in August and have been working on it almost full-time since. It will be a free, open-source application. The program can draw all the usual things: axes, grids events, and worldlines, etc. It's easy to create...
  17. R

    A Any electron/beta coincidence database?

    Hello All, I am aware of databases which list possible gamma-gamma coincidences for desired isotope. For example: here provides a table at the bottom with all possible gamma-gamma coincidence for Co-60. Question is, are there any similar databases/tables for electron coincidences with...
  18. A

    B Gamma spectroscopy, Compton edge

    Hello, I have a few uncertainties about this, Forgive the long questions, I appreciate your time. 1) Why is the maximum energy photon loses during Compton scattering about 0.238MeV (if maximum angle 180 achieved aka backscatter) irrespective of the incoming photon total energy? It seems...
  19. R

    Interpretation of Net Peak Area in Gamma Spectroscopy

    Hello, My question relates to gamma spectroscopy. I understand how the net peak area is calculated for any photopeak. Fortunately, gamma-spec software (e.g., Genie-2000 from Canberra) provides Net peak area and associated uncertainty (for Cs-137 661.7 keV peak, as an example). My question: are...
  20. patric44

    I Integral representation of incomplete gamma function

    hi guys I was trying to verify the integral representation of incomplete gamma function in terms of Bessel function, which is represented by $$\gamma(a,x) = x^{\frac{a}{2}}\;\int_{0}^{∞}e^{-t}t^{\frac{a}{2}-1}J_{a}(2\sqrt{xt})dt\;\;a>0$$ i was thinking about taking substitutions in order to...
  21. Petr Matas

    B Prevalence of nuclear decays accompanied by gamma emission

    Some alpha or beta decays produce an excited daughter nucleus, which typically immediately emits one or more gama rays to reach a ground state. This is the case for beta decay of Co-60 or Na-24 for example. While the table of cobalt isotopes on Wikipedia mentions the gamma emission, the one for...
  22. A

    How to Fix Limits of Integration for Gamma Integral #6?

    Hi I have a gamma integral in which it is not obvious how I can fix the limits of integration in order to match the standard form of gamma function.I just need someone to tell me how to fix them. I mean the integral number 6 in the picture. You can see my attempt in the PDF .
  23. AN630078

    Alpha, Beta and Gamma Energies

    Well, gamma photons are pure energy, so surely a gamma photon would have the most energy since gamma-ray photons generally have energies greater than 100 keV. An alpha particle has the highest ionising power of the three on account of its mass, it roughly has a kinetic energy of 5 MeV, whereas...
  24. H

    How to Calculate Absolute Gamma Probability from Relative Intensities?

    Hi All, I want to ask how to calculate the absolute gamma probability from relative intensities ( found on the tables of nucliedes) following alpha or beta decay. I mean the probabilities that all add to 1. Many thanks.
  25. J

    B Early Universe Radiation: Gamma to Microwave?

    Hi, Never done much cosmology but reading around I have found several sources saying the early universe (pre roughly 300,000 years) the early universe was full of gamma radiation. Since the universe has expanded this gamma radiation has been red shifted into the microwave region. Other sources...
  26. M

    Showing that this identity involving the Gamma function is true

    My attempt at this: From the general result $$\int \frac{d^Dl}{(2\pi)^D} \frac{1}{(l^2+m^2)^n} = \frac{im^{D-2n}}{(4\pi)^{D/2}} \frac{\Gamma(n-D/2)}{\Gamma(n)},$$ we get by setting ##D=4##, ##n=1##, ##m^2=-\sigma^2## $$-\frac{\lambda^4}{M^4}U_S \int\frac{d^4k}{(2\pi)^4} \frac{1}{k^2-\sigma^2} =...
  27. Jozefina Gramatikova

    Calculating Gamma, L, R1,2 for Excited Ions

    For part b) Gamma is the cavity loss coefficient, L is the length of the rod, R1,2 are the reflectivities. I am not sure how to find the number of ions in the excited state since I don't know the number of ions in the ground state.
  28. patric44

    Question related to a gamma spectrometer

    hi guys i am kinda have a vogue understanding of the working principle of the gamma spectrometer and have some questions 1 - i need some one to verify my interpretation of the working principle : the sodium iodide crystal emits photons of visible light the intensity of these photons is related...
  29. R

    B Distance covered when 22 MeV gamma rays travel through air

    Both alpha and beta radiations can only travel short distances through air as they're not as penetrating as gamma radiations. How long gamma radiations with 22 MeV energy can travel in air? Is it meters, kilometers, miles, etc. Is there a difference between a lower energy gamma ray and a higher...
  30. R

    B Which one is more efficient in generating high energy Gamma rays?

    According to https://apps.dtic.mil/dtic/tr/fulltext/u2/a351472.pdf the big pulsed power accelerator, HERMES III, generate electron beam with peak energy at 22 MeV and average electron energy at 16 MeV and the resulting photon energy which is bremsstrahlung radiation is approximately 2 MeV...
  31. R

    Differences between X-rays and Gamma rays

    Some people said if it is originated from electrons then it is X-ray but if it is originated from the nucleus it is Gamma ray. But people can produced X-rays and Gamma rays by Bremsstrahlung process and in Bremsstrahlung process it is resulted from decelerating or braking electrons. So, Gamma...
  32. R

    B Gamma rays over very large areas

    According to this link https://apps.dtic.mil/dtic/tr/fulltext/u2/a351472.pdf, HERMES III at Sandia National Labs can generate very large area gamma rays by converting the electron beam into bremsstrahlung radiations after hitting the tantalum target. As we can see in the isodose contours in the...
  33. R

    How far do gamma rays extend from an accelerator?

    According to https://www.osti.gov/servlets/purl/7234564, the HERMES III which stand for High Energy Radiation Megavolt Electron Source accelerator is "capable of delivering a peak dose of ~100 krad (CaF2) over a useful area of ~1000cm2 (area where dose is greater than 50% of the peak dose) in a...
  34. John Greger

    A Construction of real gamma matrices

    Hi! Is it possible to construct gamma matrices satisfying the Clifford algebra ##\{\gamma^\mu, \gamma^\nu \} = \eta^{\mu \nu}## that are *real*, for ##\eta = diag(-1,1,1)##? I know that I can construct them in principle from sigma matrices, but I don't know how to construct real gamma...
  35. B

    I Muon Time Dilation in Accelerating Frames

    Hi In the book, "Why does E= mc2" by Cox and Forshaw, while discussing time dilation, the example of a muon is given. The authors explain that muons when circulated in the 14 m diameter AGS facility at Brookhaven at 99.94% of the speed of light, its lifetime is increased from the value of 2.2...
  36. PainterGuy

    I Beta and gamma rays from radium

    Hi: Source: https://en.wikipedia.org/wiki/Radium Question 1: I think that the first statement suggests that it's the emission of alpha particles, beta particles and gamma rays which raises the temperature of radium sample; possibly on their way out from the sample, those particles and gamma...
  37. benorin

    I Gamma function/partial fractions (a problem from my Insights article)

    I'm typing up answers to the exercises in my Insight article "A Path to Fractional Integral Representations of Some Special Functions", this problem is from section 1 (Gamma/Beta functions). I need a bit of help with this one: The problem statement: 1.9) Use partial fraction decomposition to...
  38. O

    MHB Evaluate some kind of gamma function

    My question and solution that I've tried out are in attachment. Is it true my steps?
  39. L

    MHB How can I solve P(X>28.41) using the chi-squared distribution?

    I'm not quite sure how to solve the question with two approaches. Let X be the time taken for the cars to arrive. Given that 1 car passes every 2 mins, theta = 2. We are interested in the 10th car that passes so alpha = 10. Thus I know the distribution is Gamma~(theta=2,alpha=10) I can solve...
  40. Haorong Wu

    How to distinguish r and gamma, w and omega, v and nu?

    How to distinguish ##r## and ##\gamma##, ##w## and ##\omega##, ##v## and ##\nu## and ##\upsilon##? They look very similar. Are there some rules that I should use one of them in some specific cases?
  41. sysprog

    I Why is it possible for a sigma hyperon to decay into either 2 or 3 gamma hyperons?

    Why is it possible for a sigma hyperon to decay into either 2 or 3 gamma hyperons?
  42. D

    B Supernova Gamma Ray: 6000 Light Year Journey

    I'm watching an episode of "How the universe works" and they explained the nightmare scenario where a star supernovas and turns into a black hole, emitting such a powerful burst of gamma rays, that if it were any closer than 6000 light years then it would be capable of stripping the entire Earth...
  43. B

    Gamma factor when doing four momentum problems

    So if i had this problem where i am squaring a four momentum vector with itself which gives P2 = (##\gamma mc## )2 - ##\gamma##2## m ##2##\vec v## *##\vec v## I have been told that the gamma factor is not considered at all. why would the gamma factor drop off? Does this rule apply to any...
  44. W

    Gamma Function Q from Mary Boas 2nd ed (ch11)

    So using $$L=\frac{mv^2}{2} - \frac{1}{2} m lnx$$ and throwing it into the Euler-L equation I agree with kcrick & OlderDan that we can manipulate this to either $$\frac{d}{dt} m\dot{x} = -\frac{m}{2x}$$ or $$2vdv = -\frac{dx}{x}$$ but I'm not having any epiphanies on how to turn the above into...
  45. N

    B What happens when gamma rays with ultra-high energies interact with matter?

    What sort of properties would you expect from gamma rays, as you increase their energy, and why? Would they penetrate high Z-matter more easily? What would be the outcome of the interactions? Do you expect photoelectric and Compton scattering processes to become negligible, and the dominant...
  46. N

    Question about proportional counters for gamma rays

    I understand the concept that a more energetic photon would cause more ionization events and therefore we can estimate the original energy of the incident photon. But what I don't get is that in practice, you don't get one photon entering the detector at a time, you get a whole bunch of them...
  47. Alfredo Tifi

    I What if a body loses 86,6% of its mass as couples of gamma photons?

    After emitting two photons (or any other kind of energy) in the direction of motion and in the opposite direction, the velocity of the body (a big charged and unstable particle) remains unchanged, while the kinetic energy decreases. This entails a decrement of the rest mass, or of the inertia of...
  48. D

    I Can Laser Pulses Produce MeV Gamma Rays?

    i already know radioactivity produces gamma rays. Are there other ways to produce gamma rays in a laboratory, without radioactive substances?
  49. I

    I What would happen if wavelength could go higher than gamma rays

    We can see wave length that get compress and get higher in height when they get high energy so how would wavelength react and it how it would look like when it gets high amount of energy(like infinite energy)?
  50. 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