What is X-ray: Definition and 303 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. P

    X-ray diffraction; atomic form factor

    Hey, I'm working on a problem about the atomic form factor. I found that the atomic form factor of an fcc lattice of Buckyballs (C60 atoms) looks like f~(sin(Gr))/G multiplied bij some constants. The question is now to explain from this atomic form factor why the (2,0,0) X-ray diffraction...
  2. U

    X-Ray Diffraction HWK Problems

    Homework Statement 1. The intensities of Kalpha and Kbeta of a Cu X-ray tube have a ratio of about 10/1. It is desirable to increase the ratio to 1000/1 by using a Ni foil as a critical absorber. What should be the thickness of the Ni foil? How much attenuation in intensity has the Cu Kalpha...
  3. D

    Medical X-ray, CT scan, Ultrasound, MRI detecting blanks ?

    This is for a sci-fi novel I’m writing, and I actually posted this at another site but the answers given were a little vague. What would occur, either on a computer monitor (or other monitoring device, depending on the machine) or on a photo film, if an: a. X-ray b. CT scan c. ultrasound...
  4. H

    X-ray Diffraction: Smallest Angle of Scattering

    Homework Statement A powdered sample of a simle cubic crystal with a lattice constat of 2.83 x 10^-10 m scatters X-rays of wavelength 1.54 x 10^-10 m. What is the smallest angle of scattering that will be observed from this sample? Homework Equations 2dsinθ = nλ The Attempt at a...
  5. C

    Unique λ at which X-ray and electron have same energy

    Homework Statement Derive an equation to show that there is a unique wavelength at which X-ray photons and electrons have the same energy. Calculate this wavelength and energy. Homework Equations Here's what I thought was relevant. There may be others! For photons: E = hf = h c / λ...
  6. C

    Unique λ at which X-ray and electron have same energy

    Homework Statement This is from Advanced Physics by Adams and Allday. Spread 8.34, Q 4. Derive an equation to show that there is a unique wavelength at which X-ray photons and electrons have the same energy. Calculate this wavelength and energy. Homework Equations For photons: E = hf = h c /...
  7. C

    Calculate X-Ray Wavelength for Lead Target

    Homework Statement The tube in a medical research X-ray unit uses lead (Z=82) as it's target. Assume the electrons are accelerated through the voltage calculated in part (b). What is the wavelength of the Kα line? Homework Equations KE=-13.6 ev ((Z-1)squared) / (1squared) KE=PE=VQ E=QV λ=hc/E...
  8. F

    X-ray reflection/Bragg's law help?

    [SOLVED] X-ray reflection/Bragg's law help?? Homework Statement The planes of atoms in a cubic crystal lie parallel to the surface, 0.81 nm apart. X rays having wavelength 0.37 nm are directed at an angle θ to the surface. (a) For how many values of θ will there be a strong reflection? 4 (b)...
  9. Evo

    X-Ray Oddities, not for the squeamish

    Watch at your own risk if your are sensitive. I still do not believe an 8 year old ate 30 metal balls and magnets. Even if an EIGHT YEAR OLD was that stupid, might they have noticed after 1or 2 that they were eating metal? An eight year old can read, right, third grade? This isn't a 2 year...
  10. T

    Medical Alignment checks of the light and X-ray fields

    I was doing a first year imaging lab (in radiography course). We were supposed to check the alignment of the collimation light, and how accurate it represents the x-ray "beam". One of the question in the task question is to determine "the x-ray fields (express this answer in cm and a percentage...
  11. T

    X-Ray Tube Emission: Wave Particle Duality Explained

    In a lecture today our lecturer illustrated the idea of wave particle duality and gave some experiments that show evidence for the particle side of things. Namely photoelectric and x-ray tube. If I get this right the basic idea is that free electrons are accelerated through a potential...
  12. hagopbul

    X-ray process and electrons involved

    :confused:the X-Ray the process is like this: An electron hit the metal so there is a photon is emitted. My Q is what happened to the electron that cases the X-ray And what is K(a),K(b),K(g). Or we call them K(alpha),K(beta),K(gamma).
  13. H

    Bragg Reflection w/ X-Ray tube voltage

    Homework Statement When a beam of monochromatic x-rays is incident on a particular NaCl crystal, Bragg reflection in the first order (ie w/ m=1) occurs at theta=20 degrees. The value of d = .28nm. What is the minimum voltage at which the x-ray tube can be operating? Homework Equations...
  14. N

    Comparing K-Characteristic X-Ray Energies of Carbon & Magnesium

    Homework Statement Find the ratio of the energies of the K characteristic x rays of carbon to those of Magnesium. Homework Equations The Attempt at a Solution I did it using Bohr's expression of energy...Is there any other method to do it?
  15. A

    Incident X-ray photon problem

    Homework Statement An X-ray photon is scattered at an angle of θ = 180.0° from an electron that is initially at rest. After scattering, the electron has a speed of 4.67 x 106m/s. Find the wavelength of the incident X-ray photon. Homework Equations hc/λ = hc/λ′ + KE λ′ = λ + h/mc...
  16. X

    X-ray background/peculiar velocities and the Big Bang

    I heard that the X-ray background and peculiar velocities provide evidence that leads scientists to believe in the Big Bang model. What exactly do they have to do with it?
  17. M

    Calculating Energy Difference for K Characteristic X-Ray Line of Tungsten

    Homework Statement The K characteristic X-ray line for tungsten has a wavelength of 1.94 10-11 m. What is the difference in energy between the two energy levels that give rise to this line? Express this in each of the following units. (a) joules J (b) electron volts eV Homework...
  18. M

    What is the energy of a K x-ray photon in tantalum

    Homework Statement The atomic number of tantalum is Z = 73. According to the Bohr model, what is the energy (in joules) of a K X-ray photon? Homework Equations Energy= -(13.6 eV)Z^2/n^2 The Attempt at a Solution I don't know what to use for n
  19. M

    How Does Bragg's Law Determine the Angle of Gamma-Ray Deflection?

    1. Question A cubic crystal of interatomic spacing of 0.24 nm is used to select gamma–rays of energy 100 keV from a radioactive source containing a continuum of energies. If the incident beam is normal to the crystal, at what angle with respect to the incident beam do the 100 keV...
  20. Z

    Maximising X-Ray Image Quality with Minimal Dose Administration

    Hi all, Does anyone of you know the ways in which dose administered to a patient can be minimised while still obtaining a useful X-ray image ?
  21. E

    Modelling missing hydrogens from X-ray crystallography

    I had recently stumbled upon a computer program that can automatically add missing hydrogen atoms to protein structures from files from the protein data bank. (due to the hydrogen atom having only 1 electron, hence making its electron density too low to be detected by X-ray crystallography...
  22. P

    Can Bragg's Law Explain the Peaks in My X-Ray Spectrum Measurement?

    Hello, I've got some questions about an experiment I did about the spectrum of a x-ray beam which I measured by looking at the diffraction off a NaCl crystal of the beam coming from a tungsten anode as a function of the scattering angle. The measurement I got was something like the following...
  23. J

    X-ray Mirror to be used by telescope

    Hey all!, I'm working on a project in which I have to design the shape of a mirror to focus X-rays. This is basically what I've done so far so far. I've found that if you use a parabola mirror it will focus parallal rays, but not off-axis ones. If you then add a second mirror in the form of...
  24. M

    X-Ray photon/wavelength question

    This is one of the questions on my regular worksheets we have before our tests: A fast-moving electron traveling through a vacuum tube slams into a piece of steel, coming abruptly to rest and emitting an X-ray photon with an energy of 7.90×10-16 J. What is the wavelength of the photon? I...
  25. A

    X-Ray Diffraction: Understanding Reflection Symmetry

    hi, i'm having trouble with a problem regarding X-ray crystallography. the question is as follows: ---------------------------------------------------------------------- In general, crystals can have various symmetry elements: rotation, translation, reflection, etc. however, you never...
  26. U

    Trying to understand a reading on Moseley and the X-ray Spectra

    I was wondering why Henry Moseley ploted \sqrt{f} vs. Z instead of just f vs. Z. I'm guessing it is because this way, the graph of \sqrt{f} vs. Z would be linear? But if it was just f vs. Z, wouldn't the equation just be exponential? Also, what is the significance of the L seriese and the K...
  27. magi

    Ultrasound Scans of teeth instead of x-ray?

    Hello. I took a course in Ultrasound and I wonder why dentists don't use that instead of X-ray. The patient only need to fill his/hers mouth with water and then it is possible to use Ultrasound Scans in the mouth of the patient without any jonisating radiation. It could even be possible...
  28. C

    X-ray fluorescent screens and film contrast

    It's common practice in radiography, especially medical radiography where radiation doses are relevant, to use a fluorescent screen to expose photographic film, rather than rely on the effect of x-rays on the film itself. I understand the concept of fluorescence and the overall photon...
  29. Z

    X-Ray lines from inner shell ionisation

    Hi Group I have a question about x-ray spectra. If we look at a spectrum from a typical x-ray tube with a wolfram-74 anode, we get a spectrum http://ie.lbl.gov/xray/w.htm with two lines resulting from K-shell ionisation. Question : Why is it (mostly) the electrons from the K-shell that are...
  30. Reshma

    X-Ray Photographs: Understanding Positive & Negative Images

    Perhaps this a stupid question but I am posting it anyway because I did not find a better place to ask :biggrin: . When X-ray photographs are taken of the bones, we get the "negative" image on the photographic plate. Is it possible to develop the "positive"? If so, what will the image look like?
  31. P

    How can hydrogen and lead crystals be differentiated through x-ray diffraction?

    I was given the following question: A crystal of hydrogen atoms and a crystal of lead atoms have exactly the same crystal structure, including lattice constant. How can they be distinguished by x-ray diffraction? The solutions say that the beams diffracted off the lead crystal would be much...
  32. A

    Finding Kinetic Energy of an Electron with 100keV X-Ray Wavelength

    how do you find the kinetic energy of an electron whose de Broglie wavelength is the same as that of a 100keV x-ray?
  33. D

    Who has datum about three-dimensional demonstrate of X-ray diffraction?

    if anyone own that ,please have it shared OK?Thanks!:smile:
  34. P

    Why do x-rays penetrate crystals and not reflect with longer wavelengths?

    In x-ray diffraction with crystals, what actually happens with the incident x-ray beem or photon? scattering occurs due to which atoms (plane) of the crystal?(can it penetrate into the interior of the crystal?) why doesn't the reflection occur with big wavelengths?
  35. A

    X-Ray Production in Beiser's Physics Textbook: Typo or Not?

    in my modern physics textbook 6/E by arthur beiser, the formula for x-ray production is written as (namdamin)=1.24*10^(-6)/V V*m is that a typo? how can namda have units of V*m?
  36. Q

    What is the truth behind the Russian girl with x-ray eyes?

    I'm watching a program on discovery channel now about a girl in russain bloc who can actually, get this, see through people and diagnoise their problems! She lives in poverty, and people come to her from all over russia for help since some of the doctors there cannot help her. Has anyone else...
  37. S

    Is ultrasound technology cheaper compared to x-ray technology?

    is ultrasound technology cheaper compared to x-ray technology? is it easier to construct? for example the ones to probe foetus in pregnant females. what is the advantage for using ultrasound for probing foetus compared to x-ray, apart from safety issue? thanks.
  38. T

    Q-spacing, Bragg-spacing, D-spacing & Repeat Distances Explained

    Could anyone tell me what the difference between Q-spacing Bragg-spacing D-spacing and repeat distance is? I've always thought that they were same, but seemingly not? What is the realtionship, what is Q? Its keeping me up at night!
  39. T

    X-ray Scattering: Bragg Spacing, D-Spacing, Q & Repeat Distance

    bragg spacing? how does it differ from d-spacing? and where does q fit in? And finally are all of these directly related to the repeat distance?
  40. S

    Understanding X-Ray Spectra Graphs

    just been learning how to produce x-rays by firing electrons at heavy atoms, but i am a tad confused about the x-ray spectra graph with 'intensity' on the y and 'wavelength' on the x. it shows that the minimum wavelenth is produced wen intensity=0. how is this possible?
  41. S

    How Do X-Rays Become Visible on Medical Imaging?

    Hey! Of course you can help me! :) I need some information about HOW TO MAKE X-RAY VISIBLE. I know that it depends on the atomic number, but I need it more specific, do you know where I can get some information about my problem? I don't want you to write an essay for me, but I really need some...
  42. W

    Quantum phsics and x-ray physics

    is there anyone on here who could help me out with either of these?
  43. L

    How Is X-ray Produced and Analyzed in Physics?

    Need help with "X-ray production" Hi everyone. i am in 12th grade now. im having problems with the production of X-ray... Can someone tell me how X-ray is generated? From the very begining...to the charateristic raditaoin and the Bremsstrahlung Radiation...to the intensity graph (the one with...
  44. Pengwuino

    Calculating Compton Shift of X-Ray at 300KeV, 37°

    I have a problem saying: X-rays having an anergy of 300KeV undergo Compton scattering from a target. The scattered rays are detected at 37 degrees relative to the incident rays. Find the (a) Compton shift at this angle. Now i have the angle.. but i figure i need the wavelength of the...
  45. M

    Faster than Light? Exploring X-Ray Reflection

    Faster than c! hi I read that the refractive index(n) for X-rays in meterials are less than 1(very little less than 1). I got confused ..I am using X-ray reflection at the moment. But I am not convinced by the fact that n<1 means faster than c(velocity of light in vacuum or in air)! hope...
  46. C

    How Does X-Ray Diffraction Determine Atomic Spacing in Crystals?

    Here's an interesting problem: Find the atomic spacing in a crystal of rock salt (NaCl). The density of rock salt is 2.16 * 10^3 kg/m^3 and the average masses of the Na and Cl atoms are respectively 3.82 * 10^-26 kg and 5.89 * 10^-26 kg. Now I know that density (Rho) = mass/volume and 2d sin...
  47. E

    Can anyone explain how x-ray been produced

    can anyone explain howz x-ray been produced. thank you
  48. wolram

    Exploring the X-ray Universe: XMM-Newton Studies Dark Energy

    http://www.astronomy.com/Content/Dynamic/Articles/000/000/001/604djcxv.asp XMM-Newton studies the X-ray universe from Earth orbit. ESA A mystery that has been haunting the fields of physics and cosmology has just grown deeper. Dark energy, that stealthy ghost that lurks in the...
  49. Ivan Seeking

    A Girl with an X-ray vision and Pravda

    Does anyone remember when Pravda only told the government's lies? I am posting this as a reminder that IMHO, Pravda is not a valid news source. http://english.pravda.ru/science/19/94/377/11797_phenomenon.html
  50. Antepolleo

    Universal Gravitation and X-ray pulses

    I'm having a little bit of a problem with this one. Here's the question: X-ray pulses from Cygnus X-1, a celestial x-ray source, have been recorded during high-altitude rocket flights. The signals can be interpreted as originating when a blob of ionized matter orbits a black hole with a...
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