What is X-rays: Definition and 105 Discussions

An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz (30×1015 Hz to 30×1018 Hz) and energies in the range 124 eV to 124 keV. X-ray wavelengths are shorter than those of UV rays and typically longer than those of gamma rays. In many languages, X-radiation is referred to as Röntgen radiation, after the German scientist Wilhelm Conrad Röntgen, who discovered it on November 8, 1895. He named it X-radiation to signify an unknown type of radiation. Spellings of X-ray(s) in English include the variants x-ray(s), xray(s), and X ray(s).

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  1. fluidistic

    X-rays diffraction in a solid, Bragg's law

    Homework Statement The X-rays diffraction diagramm of a cubic crystal shows lines for the following angles 2 \delta = 31.47º, 39.74º, 47.58º, 64.71º and 77.59º when the X-rays have a wavelength of 1.54 \times 10 ^{-10}m. Determine the crystal stucture of the net, the Miller indices of the...
  2. T

    Explain why x-rays source are protons which are accelerated

    In a large hadron collider at CERN, protos follow a circular path with speeds close to the speed of light. X-rays can be produced by free protons which are accelerating. Explain why this providesa source of x-rays even though the speeds of the protons are constant. Provided answer: must...
  3. N

    Calculating X-ray Photon Scattering: Change in Wavelength Explained

    I'd really like some explanations please, just looking at part (a) at the moment :) Homework Statement Suppose three 1.02 MeV X-ray photons are Compton scattered by single collisions with nearly stationary electrons. Photon 1 is scattered backwards, in the direction opposite to its original...
  4. MacLaddy

    Understanding Electron Capture and the Emission of X-rays

    Homework Statement This question actually comes from my chemistry class, but I believe it is more suited for this forum. When the process of Electron Capture occurs, proton + e --> n, an x-ray is emitted. Why is that x-ray emitted and not a photon of lower energy. Homework Equations No...
  5. W

    What are the potential risks of radiation exposure from dental x-rays?

    Hey guys, I wasn't exactly sure where to put this one--but figured here might be best. I went to the dentist this morning and they took two bitewing x-rays, which are a low amount of radiation (~0.038mSv). The claim is that, since we routinely receive ~3-4mSv per year due to radiation incident...
  6. B

    Bremsstrahlung X-rays Energy Limit

    For an x-ray tube at constant voltage I know that the maximum energy Bremsstrahlung x-ray that can be produced is directly related to the voltage on the tube. But what about the minimum energy? Is there a limit, or can all energies below the maximum be produced? I realize that adding a...
  7. K

    Can an LDR Detect X-Rays for Bounce Back Conditions?

    Can LDR detect the X-Rays? Please help me. If it does, I have to make the x ray detector for bounce back conditions.:confused:
  8. J

    WHen x-rays hit the anode is it true that they become accelerated

    Hi people :) I got two questions concerning x-rays 1. WHen x-rays hit the anode is it true that they become accelerated and as a result of thsi accelereation emmits radiation incl. x-rays? 2. in an characterstic spectrum how is it then possible to determine the exact atom which emitted...
  9. W

    Why do the K-alpha x-rays have different wavelengths for different elements?

    Homework Statement The Kalpha x-ray is emitted when an electron undergoes a transition from the L shell (n = 2) to the K shell (n = 1). Use the following equations to calculate the wavelength of the Kalpha x-ray from a iron target (Z = 26), where E0 is the ground-state energy. The problem...
  10. R

    X ray questions:What material is suitable in windows for hard X-rays?

    What material is suitable in windows for hard X-rays? What material would you choose as reflective coating of X-rays mirrors for radiation at 200 eV? Why?
  11. F

    Why X-Rays can go through Materials

    Hello! I was wondering, why X-Rays can go through some materials, such as skin, whereas light from the visible spectrum cannot go through these(although holding a flashlight to your hand does create a red glow). Likewise, why are X-Rays stopped at the bone, and not the skin? Lastly, why does...
  12. Z

    Why are beta particles less penetrating than x-rays?

    Homework Statement Why are beta particles less penetrating than x-rays?
  13. R

    Solve X-ray Reflection Homework: Find Crystal Plane Spacing

    Homework Statement X-rays of wavelength 0.09 nm are incident on a crystal. A reflected beam is observed at 36 degrees from the incident beam. What is the spacing of the planes in the crystal? Homework Equations Bragg's law: 2 d \ sin \theta = m \lambda The Attempt at a Solution...
  14. N

    Why are X-rays absorbed in the atmosphere.

    X-ray observations of outer space are usually made from orbiting platforms. Yet radio and optical astronomy seems to work pretty well. I got to thinking that it seems odd for the highest energy electromagnetic radiation to be so well blocked by Earth's atmosphere...I would have thought...
  15. N

    X-ray tube Questions - Accelerating electrons, Why X-rays

    Hey guys, I have a couple of questions regarding X-rays and how they are produced. 1) Is an X-ray an electromagnetic wave or a photon? 2) Why is it that when the electrons collide with the anode in an x-ray tube, X-rays are emitted and not any other electromagnetic wave/photon? 3) When the...
  16. Y

    If we saw the x-rays could we see whatever the x-rays machines see?

    if we saw the x-rays could we see whatever the x-rays machines see?
  17. S

    How does a linear accelerator produce X-rays?

    Hi all, I am new to the forums, so try to persevere with my general lack of knowledge. I am a student at high school and we have just recently been studying a unit in nuclear and atomic physics. I understand all the basic concepts such as the photoelectric effect, Planck's constant, electron...
  18. S

    Diffraction of x-rays by crystals

    :shy: By looking at the figures showing diffration of x-rays by crystals, it looks more like reflection.. Seems like I am studying reflection... So, where is the diffraction part??
  19. D

    Is there a certain material that absorbs X-Rays so that the X-Rays don't escape

    Is there a certain material that absorbs X-Rays so that the X-Rays don't escape. Or rather, is there a material that stops the X-Rays from continuing. If there is such a material, is there a way to change the X-Ray into an electrical current?
  20. F

    Characteristic X-rays: Direction of Emission?

    Hello physics forum, I'm running an experiment where characteristic x-ray are produced from an Iron sample, and I was just wondering if these x-rays are emitted in any random direction, or is there a "favored" direction they can be emitted in? Thank you in advance. Neville.
  21. B

    How Do X-Rays Reveal Bone Structure and Can Their Settings Be Adjusted?

    Does it have to do with the density of the bone, like are x rays only absorbed by dense matter?
  22. J

    X-rays and their emission spectrum

    About the intensity of x-ray emission spectrum of Molybdenum as a function of wavelength for various applied voltages: Explain fully: 1) the production of continuous radiation emitted 2) the absence of radiation of wavelength shorter than the minimum wavelength 3) the presence of the...
  23. S

    Understanding How X-Rays Work: Explained by an Expert

    Hello everyone, I really don't have any idea of how the x-rays work actually. Someone told me when light goes through that place becomes dark in the x-ray or something. Anyway if anyone can give me an explanation of how an X-ray work that would be awesome. x ray----------man-------board...
  24. T

    How do electrons in tungsten atoms produce X-rays?

    Hi Everyone, I'm writing a research paper on the role electron transitions play in producing X-rays and there are some points I am having a tough time clearing up. When the the cathode fires electrons at high velocity towards a tungsten anode, I understand that a series of events may take...
  25. Spinnor

    Nuclear explosion in space x-rays hit atmosphere.

    Suppose we set off a nuclear weapon 400 km above the surface of the Earth. See: http://en.wikipedia.org/wiki/Starfish_Prime When the x-rays hit the atmosphere what gets the greatest velocity boost, electrons or ions? Can we assume the averaged velocity of all boosted particles is in...
  26. T

    Rontgen's discovery of x-rays - question

    When Rontgen discovered x-rays in 1895, was he witnessing K-shell emission or Brehmsstrahlung radiation?
  27. N

    Optimizing Lead Shielding for Gamma Radiation Protection

    What thickness of lead is needed to neutralize brief exposure to gamma radiation, or at least reduce it to below 5 gray?
  28. L

    Distance traveled by X-rays in air

    Hi guys new to the forums and have a quick question about x-rays! I'm guessing that if i know how far an x-ray is traveling in atmosphere from where it is generated before being absorbed (by using a simple x-ray detector) i should be able to calculate the approximate energy of that x-ray...
  29. T

    Calculate lattice constant from x-rays

    Homework Statement When x-rays are diffracted off NaCl, constructive interference is observed at an angle of 16.3 degrees. Determine the lattice constant of NaCl. Frequency of the X-ray is 1.948 x 10^18 hz Theta = 16.3 degrees Homework Equations (As far as what we're told to use and what's in...
  30. N

    Compute Nickel Filter Thickness to Increase X-Ray Ratio

    Homework Statement If the ratio I(K\alpha)/I(K\beta) before filtering is 7.5:1 for a copper target, then compute the thickness of a nickel filter, that would increase this ratio of 500:1. Mass Absorption Coefficients (cm^{2}/g) Cu: \rho = 8.93 g/cm^{3} K\alpha (0.1542nm) \mu/\rho...
  31. V

    Can Scotch Tape Really Produce X-rays?

    A colleague showed me this: http://www.nature.com/news/2008/081022/full/news.2008.1185.html :bugeye: I first laughed at him, until he showed me it was published in Nature...
  32. M

    Effects of X-rays on cells and chromosomes

    Could someone PLEASE explain in simple language "procedures whereby scientists modify the germ plasm of plants and animals by the use of X rays?" And, how might that effect chromosomes? If you do not know, please advise where I can find this information. I am not a student and this is related...
  33. Q

    Angle of incidence and X-rays

    Problem: The index of refraction for x-rays of wavelength 0.708A incident on calcite is 1-1.85E-6. What angle of incidence will give total reflection of such X rays? Using Bagg's Law: n(lambda)=2asin(theta), I get and angle of -45.07 degrees. Is this all that is required of the...
  34. C

    Why use x-rays to study crystals?

    In order to study the structure of crystals, scientists normally use X-rays. Why do they use X-rays and not visible light? I'm thinking it has something to do with wavelengths, but I do not know why the difference of wavelenght matters.
  35. J

    Analysis of X-rays Reflected Off Copper Powder

    Homework Statement X-rays 1.54 angstrom reflected off copper powder @ 21.65º 25.21º 37.06º 44.96º 47.58º Homework Equations nλ = 2d sin(Θ) ; the Bragg equation The Attempt at a Solution The cubic latice is face centered at d110? 5 planes? I tried plotting...
  36. M

    Producing X-Rays from a Television Picture Tube

    Can X rays be produced by a television picture tube? My attempt It is possible that X-rays can be produced by a television picture tube or a Cathode Ray tube because by altering the CRT X- rays may be produced. I have no idea if that is true but i think so.
  37. S

    How are X-rays emittted from laboratory plasma?

    hi friends m a student and want to lnow how xrays are emittted from labortary plasma and xray emission dependence on the atomic number of target from which we are creating plasm.explain me with refrence to the shells thanks take care
  38. P

    Black Holes: X-rays, Gamma Rays & Light Emission

    IF nothing can escape from a black hole's event horizon, then how do x-rays and Gamma rays escape? and how does it emits light? it says in "Brief History of Time" that the light it emits is just at the boundary of the event horizon. So then how does it escape the gravity and reach earth...
  39. J

    Understanding the Interaction of X-Rays & Electrons

    Hi all, I got asked a question recently which I really should know but wasn't able to answer to my satisfaction. When an x-ray is emitted by an ionizing process, typically an inner electron is ejected and an electron from a higher orbit ``falls'' into its place. In the process an x-ray is...
  40. B

    Unraveling the Mystery: X-Rays from Black Holes

    Light cannot escape from a black hole; however, x-rays have been detected from black holes. How is this possible? is it because of the accretion disk? where does it come from? is that all there is to the answer? thanks
  41. W

    Binomial distribution - killing cells with x-rays

    Dear Fellow mathematicians and Physicists,I am doing some MC modelling on tumour growth and radiotherapy treatment modelling and would like to know: Who out there would agree (or suggest alternatives) to the theroy that the chance of a cell being damaged/hit with radiation (and therefore...
  42. M

    Calculating % of X-rays Penetrating Lead with Al Attenuation Coefficient

    Okay, the question I'm suppose to answer is: If the attenuation coefficent of Al is 1.73/cm for soft-xrays, what percentage of X-rays penetrate a piece of lead 3.00mm in thickness . . . What I seem to have is I = Io*e^(-ux) I believe u = 1.73/cm and x = 3.00mm. My 3...
  43. J

    Characteristic X-rays, intensity ratios

    Hi! What can be said about the intensity ratios of characteristic X-rays (Kalpha to Kbeta ) originating from a X-ray tube? I mean roughly and in general, not for some very specific anode material. I first thought that K-L (Kalpha) transitions would be more likely to happen than K-M:s...
  44. G

    How to Calculate the Energy and Wavelength of K-alpha X-rays for Aluminum?

    hi All can someone help me , how can I find the energy and the wavelength of the K-alpha x-rays of aluminum ,please ?:frown: I hope someone replys soooon
  45. P

    Metals, X-rays, and plasma frequency

    I was wondering if it would be fair to say that the frequency at which x-rays start to penetrate a metal would be the plasma frequency associated with the electron density of the metal, i.e. the frequency given by http://scienceworld.wolfram.com/physics/PlasmaFrequency.html or whether some...
  46. cronxeh

    Challenges in Focusing X-Rays with Lenses

    What are the current technical difficulties that prevent us from focusing x-rays with lenses?
  47. U

    The Wavelength of X-Rays Produced by 80kV Electrons

    X-ray tubes used by dentists can have voltages as high as 80kV to accelerate the elecrons to produce the X-rays. What is the most lowest wavelength that can be produced by such electons? This problem seems almost too easy... i need a check \lamba = \frac{1.24x10^3 V^{-1} nm}{80kV}...
  48. A

    Mass and linear absorption coefficients of air for Cr K(alpha) X-rays

    for this question: calculate the mass and linear absorption coefficients of air for Cr K(alpha) radiation. Assume that air contains 80 percent nitrogen and 20 percent oxygen by weight and has a density of 1.29*10^(-3) g/(cm^3) my problem: i have no idea where to start.
  49. A

    What is the wavelength of the x-rays in the direct beam?

    for the following question: a beam of x-rays is scattered b a target. At 45 degrees from the beam derection the scattered x-rays have a wavelength of 2.2pm. What is the wavelength of the x-rays in the direct beam? my problem: the question doesn't specify what the target is... so what are...
  50. BobG

    News Backscatter X-rays for airport screening

    Airports are thinking about installing new backscatter X-ray machines for screening passengers (http://www.campaignfortruth.com/Eclub/210703/CTM-airportxray.htm These screeners see through clothes, but bounce off metal and skin, leaving the traveller essentially naked to the person...
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