X-ray Definition and 306 Threads

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. Titan97

    Intensity-wavelength graph for X-ray

    The cut-off wavelength is the minimum wavelength of the X-ray emitted. But doesn't minimum wavelength correspond to maximum energy? Why is intensity zero at minimum wavelength? Shouldn't it be maximum when wavelength is minimum since ##\lambda=\frac{hc}{E}##
  2. Plat

    Geiger counter and low-energy x-rays

    I have a geiger counter, the specifications say it is sensitive to x-rays down to 30kev. I wonder where that number comes from? Am I correct in thinking that any x-ray photon that enters the geiger tube will register a count, regardless of it's energy? Perhaps the 30kev minimum is there to...
  3. Plat

    Radiation or electrical interference? Geiger counter

    First, I hope this is the correct place for this question. I am experimenting with electrical discharges at low pressure, think plasma globe, and I bought a geiger counter to make sure I am not producing x-rays. My vacuum pump is rated down to 5 pascals. The problem is that the geiger counter...
  4. Jonathan Scott

    X-ray bursts might not happen for larger neutron stars?

    A method of definitely distinguishing a neutron star from a possible stellar black hole is that it produces X-ray bursts, which have a sharp rise time and may last for an extended period. I had previously thought these occurred when hydrogen fell to the surface and was immediately fused to...
  5. Plat

    X-ray production - maximum pressure

    What is the maximum practical or theoretical pressure at which x-rays can be produced, as in a Crookes tube or cathode ray tube? I know Crookes tubes operate at 0.1pa and lower, but I need to know if I am at risk of producing x-rays with high voltage (60kv+) discharges at medium vacuum, as low...
  6. chikou24i

    Materials and x-ray diffraction

    What is the material that doesn't diffract x rays ?
  7. B

    X-ray entrance surface dose and effective dose

    I have recently had a series of lectures on X-ray physics. I have been quite confused by the concept of effective dose and entrance surface dose. I have been told that entrance surface dose varies proportionally to kV squared. I have also been told that as kV increases, effective dose...
  8. X

    Ionization & photoelectrons in x-ray solid state detectors

    As far as i understand, this is the principle of solid state x-ray detectors: 1. A photon of energy E enters the detector and goes through photoelectric absorption 2. As a result a photoelectron with energy (E - Φ) is ejected, where Φ is the binding energy required to eject the photoelectron...
  9. TheOfficialAB

    Crystal phase transition, Diffraction peak splitting problem

    Homework Statement [/B] Hi there! This is a question from a practice problem sheet I got from the lecturer of my Condensed Matter 1 course. Below are the normal vectors to the {111} and {112} lattice planes: Homework Equations [/B] Bragg Condition: \begin{equation} n \lambda = d \sin...
  10. Matejxx1

    X-ray graph (characteristic X-rays)

    Homework Statement 4. On which graph are the characteristic X-rays being portrayed correctly. Homework Equations The Attempt at a Solution ok I know that characteristic X-rays happen because the electrons in outer shells move to the lowest possible energy shell and that the change in...
  11. Calpalned

    Calculate the minimum mass of an X-ray binary

    Homework Statement Homework Equations n/a The Attempt at a Solution I don't know how to start part A and part B depends on part A. How does one calculate a lower mass limit? Is it the lower limit of an integral? I also don't understand how there can be two periods (one at 0.714 seconds...
  12. Earnest Guest

    Is the X-Ray Mass of the Coma Cluster Accurately Measured?

    Does anyone have a reliable reference for the X-Ray mass of the Coma Cluster? I've got a value of 3e13 from Gursky's 1971 report, but I got to believe there's something more recent. Googling hasn't turned up anything more reliable than some notes on lecture slides.
  13. S

    Do X-Ray Tracks in Photo Film Suggest Quantum Entanglement?

    In Understanding Quantum Mechanics, Ch.1, Sec. 5 Roland Omnes says: ".. hard x-rays can leave straight-line tracks in photographic emulsion and this is strongly reminiscent of a particle trajectory." How can we describe this in terms of the wavefunction / interaction / measurement paradigm? Is...
  14. M

    X-Ray vs Gamma Ray: What's the Difference?

    My question is, if X-Ray and Gamma rays overlap in the EMR spectrum, then how can they be classified differently. I have read about different energy levels but I'm just afraid I'm missing something is that the only difference?
  15. madhusoodan

    Why are core electrons removed from atoms on X-ray irradiation in XPS?

    [Mentor's note: Post moved to its own thread] Hi Please let me know why core electrons are removed from the atoms on x-ray irradiation in XPS, though it was easier to outer electrons?
  16. O

    Gamma spectrometry: Calibration using X-ray emissions

    I have just done an efficiency calibration measurement for the HPGe detector of a whole-body counter. Ba-133 and Eu-152 were the calibration nuclides. For a calibration at low energies I thought of using the X-ray emissions of both nuclides as well. However, the result looks quite bad - see the...
  17. blue_leaf77

    Understanding X-ray Spectra: Characteristic vs. Background Radiation

    I'm looking at a program for Monte Carlo simulation of electron trajectory in a matter. When I look at the detected X-ray spectrum, there are two distinct curves, one called "characteristic", the shape of which is peaky. The other is called "background" where the shape is continuous. My...
  18. R

    Electron Capture - X-ray or gamma-ray?

    I may be being a bit pedantic but when an electron "falls" (or is captured by) into the nucleus, does the outer shell electron that fills its place result in an x-ray or a gamma-ray being emitted? Or would it depend on the energy transition? Thanks for any ideas.
  19. Abtinnn

    Formation of X-Ray Binaries Outside Black Holes

    Just curious... I mean they don't form inside the event horizon, so how would they form outside? How does accretion do this?
  20. C

    X-Ray Diffraction peak width due to micro-strain

    I understand that the peak-width of diffraction data increases with increasing amounts of heterogeneous, localized (AKA "micro-") strain. So, if you have a single crystal with atomic impurities in it that each create micro-strain in the lattice, you would expect the amount of peak-broadening...
  21. W

    X-ray Diffraction: Crystal Structure vs. Electric Dipole

    When x-rays are incident on a crystal structure, do they diffract in the same way as light through a diffraction grating? On the one hand, I've read that a crystal structure acts like a 3D diffraction grating. On the other hand, I have been told that x-rays induce an electric dipole moment in...
  22. N

    Solid State Physics: X-Ray scattering

    Homework Statement https://fbcdn-sphotos-c-a.akamaihd.net/hphotos-ak-xpf1/v/t1.0-9/10980752_10204928958360361_5256945004598578166_n.jpg?oh=7fd9defb14be9a9befa0cf5032def429&oe=55576A2C&__gda__=1431534931_425423ae11039486a001b049726e1b11 Homework Equations Charles Kittel's book on Solid State...
  23. S

    Where Can I Find Diodes for Line-Shaped Beams in Soft X-Ray Experiments?

    I have successfully tested my read-out & data acquisition electronics for the Moxtek XPIN-XT Detector. I cooled the PIN diode below -30°C and found an energy resolution better than 300eV (@8keV) up to 50k cts/sec. Right now I am looking for diodes for line-shaped beams, i.e. about 14mm x 2 to...
  24. jim mcnamara

    Could Dark Matter Be the Source of Anomalous X-ray Emissions?

    This is a video by the two of the researchers who found anomalous xray emissions. These emissions may be related to dark mater, needs further verification. Edit 12/14/14 : preprint http://arxiv.org/abs/1402.4119
  25. P

    Neutron and x-ray inelastic scattering

    Hi guys! Im i have to write a paper on neutron an x-ray inelastic scattering. So far I have red a bit of information on this subject. As far as i can tell the main use x-ray an neutron inelastic scattering is determining the phonon energy,wave vector,intensity and so on. The thing is that...
  26. TESL@

    X-ray to Microwave fluorescence

    Hello, Is there any specific element that would absorb x-ray and emit radiation roughly in microwave band (not thermal radiation, fluorescence). Or could it be achieved by mixtures and gradual wavelength increase? Thank you.
  27. G

    Energy Resolution of a solid state X-Ray detector

    Homework Statement Hi all, I have been given the task of quantifying the energy resolution of a p-i-n semi-conductor x-ray detector and present it as a value in electron volts Homework Equations %Resolution=E FWHM / Ei Where E FWHM is the full width half maximum of a peak and Ei is the...
  28. L

    X-Ray Diffraction Homework: Deriving (2theta) Values

    Homework Statement A crystal composed of two fractions, one having the a cell parameters of 4.123A and the other of 3.997A are subjected to X-ray diffraction using both Cu k-alpha and a Mo k-alpha radiation. Derive the angular position of (2theta) for (100) and (110) planes. Explain the...
  29. B0b-A

    The force was not strong enough to detect Darth Sidious

    So they used X-rays instead ... http://m.bbc.co.uk/news/uk-england-nottinghamshire-29627037
  30. D

    Effect of changing target metal to heavier metal in X-ray tube

    Homework Statement when target metal is changed to heavier metal in X-ray tube, the min wavelength will not change. but the wavelength of the characteristics line will become smaller. my textbook gives me the above statement explaining much. can someone please explain it? thanks ! Homework...
  31. A

    Electron Diffraction, and General X-Ray (EBSD- Kikuchi lines)

    Hi guys, new here. We all know the famous "Bragg Law" and the attached schematic drawing that goes along with it of a couple of planes with a distance `d` between them. Then, a DP occurs cause of constructive interference and destructive interference which happens due to planes deep in the...
  32. S

    Tungsten x-ray target replaced by molybdenum.

    In an Xray tube containing tungsten target , 50kV voltage is applied. Calculate the minimum wavelength of xray emitted. If the target is replaced by molybdenum will the min. wavelength change. Justify your answer? I used λ min= hc/eV= 2.481×10^ (-11) m for the 1st part. For the 2nd part I am...
  33. R

    Difference between X-ray Diffraction techniques and Raman spectroscopy

    Hi everyone, I'm little bit confuse about non destructive techniques such as XRD (X-ray Diffraction) and Raman spectroscopy, I know that both techniques can determine the crystal structure of the certain materials, and also, I know that XRD is working with the principle of emission of x-ray...
  34. T

    X-ray crystallography - Electron-density map

    Homework Statement Hello, i have the following task in my homework: When doing an X-ray crystallography experiment to determine the structure of biomolecules (protein/DNA), why do consider interpreting an electron-density map (EDM) instead of directly using the diffraction data? 2. The...
  35. S

    How does x-ray diffraction from different Bragg planes add up?

    I'm writing a little bit of Mathematica code that should be able to make a reasonable powder diffraction spectrum. The algorithm is like this: Take Bravais lattice and basis. Compute reciprocal vectors. Compute structure factor (and its square magnitude) Have triple nested loop that creates...
  36. M

    Photon emission during x-Ray ionization process

    Dear mates: During ionization with radiant energy there is a photon emission (see http://hyperphysics.phy-astr.gsu.edu/hbase/mod3.html). I know photon emission occurs by a decay of radiant energy from a excited state and what is confusing to me (I can't find a logical conection) is that...
  37. A

    X-ray Photoelectron Spin-orbit Splitting

    I have some XPS spectrums that I am trying to fit (my first time doing so), using XPSpeak. I understand that for spin-orbit splitting the FWHM, line shape (i.e.% gaussian/lorentzian) must be equal (more or less), peak area ratios set (i.e. 2:3 for 3d3/2 and 3d5/2), and the peak separation...
  38. S

    Enhance Visibility with Metal Spray Coating for X-Ray Applications

    Hello fellows, i would like to ask if you might know any spray with metal elements which can be visible in X-rays. I want to use it as coating in objects. Does any common gold or plat spray be used? Thank you!
  39. M

    X-ray applications in solid state physics

    hello everyone, i am looking for a comprehensive link for the topic above as i want to do some research on various applications of x-rays in solid state physics. its a personal research but i have some materials but i still feel i need a whole lot more. Any form of help would be appreciated...
  40. T

    Unraveling X-Ray Diffraction: Questions & Answers

    I'm working on a physical chemistry project that is a report on a paper that uses X-ray crystallography to characterize a protein. So I am studying X-ray crystallography more in depth than the book introduces, and I have a few questions that I couldn't really find answers to online. 1. How...
  41. U

    Silver Atom X-Ray Spectra: Kα & L X-Rays?

    Homework Statement For a silver atom, energy corresponding to Kα transition is 21.75 KeV. Also minimum energy of a striking electron so as to produce L X-Rays is 3.56 keV. Now, if electron with an energy of 23 keV strike a silver target the characteristic X-rays spectrum will have a)only kα...
  42. J

    What is the optimum voltage for an X-ray tube and why is it important?

    Hi all, I hope this is the right place for this question. What effect does increasing voltage have in an X-ray generator? What's the optimum voltage for the most efficient production of X-rays and why? Thanks
  43. D

    X-Ray Diffraction: Solving for θ Using nλ=2dsinθ

    Homework Statement It's got a diagram in it so I have just attached a picture of it. Homework Equations nλ=2dsinθ The Attempt at a Solution I've really got no idea how to proceed with this one. I think you have to consider the effect of the thin film as well. Any ideas?
  44. PsychonautQQ

    How Does Copper's X-ray Wavelength Relate to Aluminum's Bragg Angle Calculation?

    Homework Statement I'm a bit confused by this question. It starts off by saying a Cu target emits an x-ray line of wavelength λ=1.54 Angstroms. It then goes and says part A of the problem.. A) Given that the Bragg angle for reflection from the (111) planes in Al is 19.2 degrees, computer the...
  45. PsychonautQQ

    Calculating the Kinetic Energy of an Electron in X-Ray Radiation

    Homework Statement The minimum wavelength observed in x-ray radiation is 1.23 angstroms. (1 angstrom = 10E-10m). What is the KE, in eV, of the primary electron hitting the target? Homework Equations eV = hc/λ and since all the potential energy becomes kinetic... is the answer simply...
  46. S

    Can Any Molecular Crystal Be Used in Bragg's X-Ray Spectrometer?

    In Bragg’s spectrometer used to determine the wavelength of X – rays why should we make use of only NaCl crystal,cant we use any other molecular crystal?:rolleyes:
  47. dheeraj

    Understanding X-Ray Emission from Colliding Electrons

    i everybody i've studied in my 9th standard that x rays are produced when cathode rays(electrons) hit solid targets such as molybdenum,titanium,etc.. now we'll observe the physics going out there so what's happening there? an electron is coming with some speed say v and hitting the valence...
  48. Z

    X-ray crystallography, protons or electrons?

    X-ray crystallography is now 100 years old so this question is probably pretty simple. Is the diffraction coming from the nucleons or the electrons in the sample? Ie. The electrons occupy a more diverse location within the sample (depending on what level/shell they occupy, in fact some may be...
  49. S

    X-ray diffraction or reflection?

    In x-ray diffraction , even though its reflection is happening , we call this as x ray diffraction. why is it so?? i don't know whether it has been discussed previously here.
  50. Q

    Minimum daily whole-body X-ray dose to cause radiation poisoning?

    Hi, If I were given a whole-body X-ray dose daily for many days (a year for example) What would be the highest dosage per day which would result in an increased cancer risk but no noticeable signs of radiation poisoning by the end of the year, or during? And also, I've read that a 2KRad dose...
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