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. S

    How are allowed and forbidden reflections calculated?

    Question: Explain the rules of reflection for different cubic lattices (SC, BCC, FCC) based on the Bragg ́s law. Help: If we have incident of X-rays, which planes have constructive/ distractive reflection? Why? Please calculate it for the following crystal planes. 001, 011, 111, 200, 210, 211...
  2. L

    What types of light can safely pass through the human body?

    What types of light are able to pass through the human body without causing damage to tissue or individual cells? Are there any truly safe alternatives to x-rays that could allow doctors to see internal body parts but not cause damage from extended exposure?
  3. L

    I X-ray diffraction minima?

    For x-day diffraction maxima we have braggs law 2d*sinθ = mλ (maxima) Is there an analogous law for the minima like 2d*sinθ = (m+1/2)λ (minima?) Thanks!
  4. B

    What is the potential for extremity doses in this X-ray exposure incident?

    Homework Statement A research worker is irradiating some drug samples in an x–ray beam. The tube is running at 60kVp with a tube current of 4mA. Although the ‘shutter open’ lamp is extinguished, indicating the shutter is closed , it is faulty and the researcher loads his samples with the...
  5. 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...
  6. Asmaa Mohammad

    Target element in Coolidge tube and x-rays

    Homework Statement Homework EquationsThe Attempt at a Solution I would say that the wavelength of the characteristic spectrum will increase, but what about the bremsstrahlung spectrum? Will the cutoff wavelength will be longer?
  7. C

    A Warren X-ray difrraction solutions manual

    Does anyone knows where I could find the answer to the problems in the classical book on x ray Diffraction by B. E. Warren "X-ray Diffraction" ? It's not an easy-to-read book so I think that checking my solutions to the problems would be really helpful. thanks
  8. K

    I High Resolution X-Ray Diffraction: Explained

    Hello What does it mean when people say high resolution xray diffraction? What is the difference between regular Xray diffraction and high resolution X-ray diffraction? Thank you
  9. V

    Calculate vmax and voltage from X-ray distribution function

    Homework Statement The X-ray intensity distribution function for an X-ray lamp is given on the figure. What is the maximum velocity of the electrons? What is the potential difference under which the lamp is operating? Figure: http://imgur.com/01kCBc8 Homework Equations Kmax = 0.5m(vmax)^2...
  10. sarvesh upadhyay

    A X-Ray Diffraction: Why Doesn't It Eject Electrons?

    X-ray has enough energy to eject the electron in the atom, molecule etc. But in the x-ray diffraction electron does not eject, only oscillate with the same frequency as X -ray,why? Why does not x-ray eject the electron?
  11. Asmaa Mohammad

    Calculation of the least value of PD needed to produce x-rays

    Homework Statement [/B] In my excercise book, I was given a typical diagram as that in Fig (6-7) above. And the problem statement says: The diagram presents the x-ray spectrum produced by Coolidge tube. Determine the least potential difference needed to produce the characteristic radiation...
  12. A

    Why Does X-Ray Scatter at Angle 2dsinθ?

    This question is as dumb and simple as it can be: Why is the path difference 2dsinθ? Or better said: Why x-ray scatters like in the image? (Couldn't there be another scattering angle for both atoms other than θ?)
  13. John Covert

    Is lead salvaged from hospital x-ray shielding safe?

    I am a lay person, so the physics lesson would only confuse me. I do reloading of ammunition for competitive shooting (Cowboy Action Shooting). I have someone offering to sell lead for melting and casting bullets. He has indicated its source was shielding from hospitals used in X-ray shielding...
  14. M

    X-ray tube flux and my experimental test setup

    Hi everyone! I'm starting to work with a mini X-ray tube provided by Amptek. I want to use it to calculate the efficiency of a detector I'm going to use latter, so knowing the total flux the tube emmits and measuring the flux the detector receives, that should be enough (both data normalized to...
  15. MrRobotoToo

    I Further Evidence of a 3.5 keV line in Galactic X-Ray Spectra

    That pesky 3.5 keV line just won't go away. The authors note that it's compatible with dark matter composed of 7.02 keV sterile neutrinos. If such is the case, the Majorana mass scale of the seesaw mechanism needn't coincide with the GUT scale (if such a scale even exists).
  16. C_Pu

    I Peak profile fitting in X-ray Crystallography, why Voigt?

    Hi,I've been doing a lab cycle on X-ray crystallography. We are using Cu X-ray source on chloride salt crystals. It seems that the Bragg peak profile are commonly acknowledged to be a Voigt function, which is a convolution of Gaussian and Lorentzian. I am wondering what's the physical reason for...
  17. T

    Calculating Bragg Angles for X-Ray Scattering from Table Salt Crystal

    Homework Statement The Spacing between the Na and Cl atoms in table salt (NaCl) is ##d=2.82x10^{-10}m##, which was first deduced from Bragg scattering. For an experiment where X-rays of energy 20 eV are produced, what are the corresponding Bragg angles below ##90^{\circ}## for scattering from a...
  18. Samar A

    B What is the minimum voltage required to get characteristic spectrum

    Hi, The x-ray consists of the bremsstrahlung spectrum and the characteristic spectrum. We can get x-rays by using Coolidge tube where there are an applied voltage on the tube between the filament and the target. The bremsstrahlung is depeding on the PD between the filament and the target, but it...
  19. N

    X-ray crystallography; intensity peaks vary with voltage

    Homework Statement I have done a simple lab experiment to find the lattice constant for NaCl. Using a diffractometer, radioactive counts were measured as a function of crystal orientation angle for electron voltages of 20 and 30 kV. The average lattice constant found wasclose to the accepted...
  20. Cool4Kat

    How did Roentgen rectify current in the first x-ray?

    Hi, I was studying Roentgen (and Crookes tubes) and realized that they used spark gap generators which sent out bursts of AC current. However, Crookes tubes work with one end being the cathode and one the anode. They did this before diodes so how did they ensure that one side was negative and...
  21. C

    I Visible light reflection v.s X-Ray reflection

    I'm a bit new to studying physics so I hope this question doesn't sound off. I already know this "Photons are emitted from an atom when an electron transitions from one state to a lower-energy state. The energy of the emitted photon equal to the difference in energy between the two states."...
  22. W

    In X-ray diffraction, what is the virtual source?

    In X-ray diffraction, during the experiment a X-ray beam will create an incident and diffracted beam, but what exactly is the virtual source? I may be mistaken but isn't the source the incident beam, in the attached image, it seems to suggest otherwise?
  23. Bloopy

    Effect of Change of Potential difference applied to an X-Ray tube

    I am a high school student, so I know only the basics of X-Rays.I simply know about continuous X-rays, cutoff wavelength and threshold wavelength. Now if I increase the potential applied to the X-ray tube, I am certain that the minimum wavelength of emitted radiation decreases. (I say this using...
  24. A

    I China launches X-ray Pulsar NAVigation satellite

    China launched five small satellites Thursday, including the X-ray Pulsar Navigation satellite that eventually could help spacecraft headed for deep space navigate, the latest piece of China’s ambitious space program, NASA Spaceflight.com reported. The X-ray pulsar, developed by Aerospace...
  25. Clara Chung

    Question about x-ray, concept confusion

    1. Must the electron brought to rest(in one step or many steps) in Bremsstrahlung effect? 2. Besides from a coming electron knocking off an electron on the shell then another electron fills the void, can the coming electron just excite an electron on the shell to a higher state and release a...
  26. P

    Understanding X-ray Emission: Unraveling the Confusion

    Homework Statement Although not a computational problem, I still have difficulties understanding emission of characteristic X-rays. Can someone please clear up my confusions about the topic? Here's where I'm stuck, with two texts as an example: Source for the above...
  27. C

    Chest X-ray Radiation and Its Impact on Other Body Parts

    If you have chest x-ray of the lungs.. how much of the x-ray radiation goes to other parts of the body (like the lower abdomen)? Or do the machines just focus the beam on the chest?
  28. K

    X-Ray Shielding (Scanning Electron Microscope)

    Hallo everyone, I have a question about X-Ray shielding in a scanning electron microscope and I hope you can help me! The topic is that when electrons hit the specimen, characteristic radiation up to 10keV is generated. This radiation is blocked/decelerated my the surrounding tower and chamber...
  29. R

    X-ray emission from a klystron tube

    So, I was thinking about building a low power klystron (around 5W.) I know this involves making an electron gun and electron guns can emit x-rays. I have a few questions: 1. Will 5W produce x-rays? 2. If so, what is a safe dosage of x-rays? 3. How can I shield myself and others from the...
  30. Alfreds9

    Where could I look for down-to-earth X-ray facts?

    Hello, I'd like to know which book or papers I'd read to understand, possibly without too rigorous mathematics knowledge, how do photons like X-rays or gamma ones reflect off surfaces and attenuate through solids or generally speaking, facts about how do they interact with the real world. So...
  31. C

    Stationary Target X-Ray Tubes - Energy

    Homework Statement An x-ray tube with a stationary target is operated with a constant voltage and current of 100kV and 50mA for 0.2s . Approximately how much energy will be deposited as heat in the target and how much emitted as x-rays? Homework Equations ##P=IV## ?The Attempt at a Solution...
  32. H

    I Solid State NMR and X-ray Crystallography resources

    Hello, I need to learn how Solid State NMR and X-ray Crystallography work (theory and practical application). I'm primary interested in how those experimental techniques are used to determine molecular structures. I'm an undergrad physics student and I need this to pass my final exam. So if some...
  33. A

    I X-ray spectra- bremsstrahlung and characteristic x-rays

    Hi all, In an x-ray spectrum, the curve part represents the bremsstrahlung part, and the spikes are the characteristics x-rays. Characteristic x-rays represent a discrete energy. However, in many textbooks, I noticed that the characteristic x-rays are often represented as a peak, which implies...
  34. AndresPB

    Medical Electron Acceleration and X-Ray Emission in X-Ray Machines

    Good morning all, I was just wondering the following question. When an electron is accelerated it emits electromagnetic radiation, depending on how much it is accelerated the energy varies so the frecuency does and the electromagnetic wave emitted would be of different colors or maybe even...
  35. JBC

    I Bayard Alpert Gauge X-ray limit

    When the cathode emits electrons which are accelerated towards the grid, usually on its way it will ionise a molecule in the vacuum. However at a certain low pressure there are too few molecules and therefore the electron will hit the grid and emit an x-ray. My question is, wouldn't electrons...
  36. AndresPB

    Medical What are the Technical Specifications for the KL27-0.8-70 X-Ray Machine?

    Good afternoon, I'm doing a research on x-rays machines. I chose the model KL27-0.8-70 (or any oral x-ray machine). I would be very grateful if someone could provide me some technical information as the radiation pattern, the aceleration efectuated on the electrons, and the electric field...
  37. B

    X-ray Tube Output: 80μGy/mAs at 1m, 900µGy/s @1m

    Homework Statement (The question is in the image attached) (c) An X-ray unit in the cardiac catheter labs has an output of 80µGy/mAs at 1 meter when the unit is set at 100 kVp. After adding 0.3mm Cu to the beam the photon intensity is reduced to a quarter and tends to vary in proportion to...
  38. super_adun

    I K-beta line for the X-ray spectra of Molybdenum with Moseley

    This should be easy but I'm totally stuck here. So I'm calculating the Kβ line (emitted energy) of Molybdenum (Mo 42). I'm using Moseley's law and am moving from the M-shell to the K-shell. Recall Moseley's law is E = 13.6 eV (Z-σ)2 *1/n2. The effective formula for the energy emitted is thus...
  39. B

    Mo Anode X-ray Filtering in Mammography: Why is Mo Ideal?

    In mammography, an Mo anode is used because it produces characteristic X-rays at about 17-20 keV. Apparently, the ideal filter is also Mo. Why is this? Surely all the x-rays would just be re-absorbed by the filter? Thank you
  40. A

    Managing X-Ray Hardness and Low Frequency Use in Tissue Analysis

    I got question in exam, 1) How to control hardness of X-ray? 2) why low frequency of x-ray is used for investigating tissue?? so in 1) what does controlling hardness means?? and in 2) can't we use high frequency of X-ray ?so that it will penetrate more as tissue are poor absorber...
  41. B

    Small focal spot in X-ray imaging

    Unfortunatley I cannot post this question in the Homework section (not sure why) so I hope its OK if I post here and show work as appropriate < Mentor Note -- thread moved to HH from the technical physics forums, so no HH Template is shown > QUESTRION State two design features in an X-ray tube...
  42. D

    A About X-ray Photoelectron Spectroscopy

    Hello, I am trying to create peak models for some XPS spectra. I have a decent intuition of the chemistry of the samples, and I obtain really good residual standard deviation values for the modeled data; however, some of the FWHM of the modeled oxidized species (C and P) on the narrow scans are...
  43. Salvador

    Do Vacuum Tube Amplifiers Emit X-Rays at Lower Voltages and Frequencies?

    I recently got an older tube amplifier , since ti was dirty from being left for a long time in an old shed i took the covers off and cleaned it , now I am listening it also with the covers off , everything works etc. Now I wonder do tubes at lower voltages and lower frequencies such as in the...
  44. B

    "SNR in X-ray Imaging: Calculating & Effects

    Homework Statement (1) An ideal digital detector only suffers from quantum noise. If, after being exposed to 5 µGy the mean pixel value in the image is 100 and the standard deviation of the pixel values in the image is 5, calculate the SNR? The relationship between pixel value and detector...
  45. DetectiveT

    Gamma and x-ray decay in different series

    Is there any gamma decay or x-ray decay in Actinium series, Uranium series or Thorium series? On Wikipedia, it only shows alpha and beta decay, does it mean high energy photon decay (gamma or x-ray) exists in each process? Thank you! https://en.wikipedia.org/wiki/Decay_chain#Actinium_series
  46. Kelly Green

    Bragg's Law (X-Ray Analytical Methods)

    Homework Statement Explain using word, diagrams, and/or calculations.. (1) Why must n always be <= 2d/λ? (2) If λ is significantly greater then d, why will no diffraction occur? Homework Equations Bragg's Law nλ=2dsinθ n has its maximum when sinθ is 1 (at 90°) The Attempt at a Solution I am...
  47. N

    B Could the opacity of a material to one band of EM radiation be altered by X-ray illumination?

    -iation. Could the opacity of a material to one band of EM radiation (light) could be altered by irradiating the material with another band of EM radiation (X rays)? I think you are suggesting that: By raising the electrons in the atoms to higher energy bands (with the X rays), so that they will...
  48. 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}##
  49. 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...
  50. 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...
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