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. D

    X-Ray Diffraction: Single Crystal Peak?

    Hello all, I have a basic question with the theta-2theta technique in XRD. Here it is: If I have a single crystal material and I perform the above mentioned characterization. Should I get one diffraction peak associated to the orientation of the bulk crystal or should I get many peaks...
  2. E

    SAXSess from Anton Paar (Small angle x-ray scattering camera)

    Is there any user on this forum who have used the SAXSess? please reply to this post. I need some discussion.
  3. R

    X-ray absorption by semiconductors

    Hi, i am doing a project course in masters. i need help regarding on X-ray Spectrum absorption by semiconductors. I am doing the simulations in XOP(X-ray oriented programs) software which is freeware at http://www.esrf.eu/UsersAndScience/Experiments/TBS/SciSoft/xop2.3 . So, my doubt is...
  4. P

    Emission current from hot cathode in an X-ray sourse

    Part of an experiment involved measuring the intensity of an X-ray beam through a piece of aluminium as a function of emission current of the X-ray source. I originally fitted a linear fit to my data (although it does start to level off at high emission currents). The marker however said that it...
  5. E

    Medical Microcalcification in X-ray mammograms

    Dear all, Micro-calcification is an indication of breast cancer at its early stage and appears as bright spots in X-ray mammograms. My question is that X-ray attenuates much in calcium than in regular soft tissue in the human breast, e.g. glands, milk duct, adipose, etc., should not...
  6. L

    X-ray Cystallography -Calculating Density

    Hi, In our lab session on x-ray crystallography we found values for d, the plane separation using Bragg's law and from that we are supposed to find the density of the crystals (Lithium Fluoride, Rubidium Chloride and Potassium Chloride). However, when we calculated the densities they were...
  7. S

    Comparing X-ray & MRI Scans: Bone & Soft Tissue

    Hi i am new here so, please take it easy with me lol i have afew Q and i relly need help with them 1) compare and evaluate the appearance of bone and soft tissue in an MRI scan compared with a conventional X-ray. 2) Explainthe factors influencing the signal intensity in MRI. Thank...
  8. E

    If we saw x-ray waves could we see the inside of the objects?

    if we saw x-ray waves could we see the inside of the objects?
  9. C

    How X-rays Compress Matter for Nuclear Fusion

    I read on Wikipedia that x-rays are sometimes used to compress nuclear fuel to initiate fusion reactions. This is probably a stupid question, but how can electromagnetic radiation compress matter?
  10. S

    Wave length for a bragg diffraction from a incident x-ray.

    A cubic crystal with a lattice constant "a" is mounted with a [100] direction parallel to the incident x-ray beam. what would be the wave length for a bragg diffraction to occur from (110) and (111) planes? So Bragg's law is: 2d sin (theta) = n wavelength. So my thoughts are: This is...
  11. R

    Fine structure of X-Ray transition

    What's the main reason behind the fine structure of X-Ray transition?
  12. M

    X-ray Diffraction, Intensity vs. Wavelength Graph

    Homework Statement http://b.imagehost.org/0607/Question_7.png Homework Equations [PLAIN][PLAIN]http://d.imagehost.org/0813/Untitled_6.jpg The Attempt at a Solution I was able to get question b, which ends up being 73pm, but as for questions a and c, I was unable to come up with...
  13. M

    Planes of simple cubic structure and X-ray diffraction experiment

    In the book of the Dr. Ronald Askeland the problem about x-ray diffraction use the next planes indices to calculate the interplanar distance, but I don't understand why to use such planes indices? Are these planes all of planes in a cubic structure? (111) (200) (211)...
  14. Useful nucleus

    X-ray diffraction for 2-D crystal

    Is it possible to perform x-ray diffraction for 2-D crystal like Graphene? If poossible how does the bragg interference criteria look like here?
  15. C

    Photoelectric absorption in x-ray imaging

    I'm sure I'm overlooking something simple here. I am trying to understand characteristic x-rays given off during photoelectric absorption of a photon. The energy from the photon is given to an inner orbital electron and the photon no longer exists. The electron uses the energy to escape, and...
  16. Philosophaie

    HLX-1 brightest ultra-luminous X-ray source known.

    The most extreme ultra-luminous X-ray source, HLX-1 is 300light years from Earth. HLX-1 is the brightest ultra-luminous X-ray source known. Also it is not a supermassive black hole but it is the center of the galaxy. How can it be the brightest x-ray source and be a small black hole?
  17. A

    Discovering Chandra X-ray Field of View & Object Size at 500 pc Distance

    What is the field of view of a single Chandra X-ray Observatory ACIS CCD chip and how many times could a single CCD fit across the disc of the Moon? If an X-ray source completely fills a single CCD and is located at a distance of 500 pc, how many kilometers across is the object
  18. O

    X-Ray Emission from Synchrotrons vs. Cyclotrons

    Why do accelerating electrons (synchrotron) emit x-rays, but accelerating protons (cyclotron) don't? Both are accelerating/decelerating charges.
  19. S

    Power of laser vs Power of X-ray

    Hi, I wonder how to compare the power of a laser and an X-ray. For example 1mW power of a laser hitting an object is comparable to the an X-ray generating 1mW of power? Thank you.
  20. A

    X-ray Diffraction: Why Are Peaks of Different Intensities?

    This is not really a homework question but a more general plea for an explenation from someone! :) In x-ray diffraction, you get a graph with different peaks that are particular to the composition of your sample. But, why are some peaks are of higher intesities then others? What is it about...
  21. T

    X-ray structure analysis question

    Hello everyone! I have met such a curious thing: When chemists tried to synthesize CaCl by reducing CaCl2 with H2 they got CaClH instead, but the structure of a compound was determined using X-ray structure analysis which is not suitable for determining the position of light elemnts like...
  22. O

    X-Ray Spectrum of Copper Tube at 20kV

    Homework Statement Sketch and label the x-ray spectrum for an x-ray tube with copper as its target, operating at an excitation potential of 20kV.Assume that the copper energy levels are K shell=-9000ev,L shell=-1000ev,M shell=-200ev. Homework Equations This question has me a bit...
  23. N

    Thermal Goggles, X-Ray Goggles, ?

    I have no clue where to post this in the forum, but this seemed like a good place. So of course there exists a thing like thermal goggles. Maybe it's partly due to me being still somewhat a kid (19 years old), but it seems terribly fascinating to be looking into a whole new spectrum: the...
  24. K

    Searching Samples for X-Ray Analysis

    We are doing a project for which we have to find a use for a certain machine. This machine uses x-rays together with special software to make a 3D image of an object. The software can “cross-cut” the object so its inside can be seen as well. Lastly the software can analyze different aspects of...
  25. T

    X-ray Diffraction: First-Order Bragg & 2nd Order Angles

    Homework Statement First-order Bragg diffraction is observed at 25.9degrees relative to the crystal surface, with spacing between atoms of 0.26 nm. a)What is the wavelength of the X-rays? b)At what angle will second order be observed? Homework Equations m\lambda=2dsin\phi The...
  26. E

    What is the energy of an X-ray photon with a wavelength of 6.6*10^–11 m?

    Homework Statement The X-ray spectrum of molybdenum has a particular characteristic spectral line of wavelength 6.6 *10^–11 m. The ionisation energy of molybdenum is 20 keV. Deduce that the energy of an X-ray photon of wavelength 6.6*10^–11 m is 19 keV. Homework Equations E=h*f...
  27. M

    Medical Pain from X-Ray? Dr. Gregory Greenman Answers

    Dear Dr. Greenman, I have a question wherefor I do not find the way how to post it on the forum. It is related to radioactivity;: I had to lett taken a X-ray from my longs. When the machine made a grumpy noise, the picture got taken, but at that instant suddenly the whole side of my...
  28. M

    X-Ray Diffraction Equation (Mineralogy HW)

    Homework Statement Okay so, I was hoping someone out there might be able to assist me with a Mineralogy problem I have. The concept is based around X-Ray Diffraction. The question: Derive a diffraction equation from the illustration below that relates the reflection angle (theta) to the...
  29. C

    Bragg angle and X-ray Radiation

    Homework Statement In an experiment with X-ray radiation, you use a continuous radiation from an X-ray pipe. What is the highest energy of the X-ray radiation you can get if the pipe's acceleration voltage is 40 kV? If we use radiation with double the wavelength of the maximum energy we get...
  30. R

    Exploring X-Ray Ionisation: Common Questions Answered

    Hello, I am fascinated by the properties of x-rays and their many uses, but i need to clarify a few things: 1) Can x-rays eject electrons from non-metals and possibly even gases, or is compton scattering constrained to metals only? (ie. photoelectric effect) 2) How do you synthesize...
  31. T

    Confirming Solar Wind & X-Ray Flux Effects on Earth's Magnetic Field

    This is more of a confirmation that I got the facts right: Reading around, I found out that the solar wind travels from the Sun to the Earth at a mean speed of 400km/s. Does this mean that it takes around 4 days for a burst of solar wind to cause disturbances in the Earth's magnetic field...
  32. R

    Understanding X-ray Attenuation: Determining Absorption Probability and Depth

    Hi all, using the mass attenuation coefficient and density, one can determine the percentage of X-rays absorbed in a material for a given depth, using the Beer-Lambert Law. e.g. The intensity of a beam of 8 keV X-rays will be reduced by 68% after passing through 70 microns of Silicon...
  33. J

    X-Ray Diffraction Homework: Find Crystal Spacing

    Homework Statement An X Ray beam (wavelength 10^10m) is incident upon a sample of a powdered crystalline material. At a distance of 5m from the sample a flat detecting film has been placed. A pattern of 2 circles have been recorded on this film (radius 2cm and 3.5cm). What crystal spacing...
  34. B

    What Causes the Spikes in X-ray Spectra?

    Hello, I have studied X-ray emission when an electron beam is fired at a tungsten target - But when I was presented with the graph of Intensity versus wavelength, I was confused... I saw a curve, and on it there were spikes. What are these spikes, and why are they caused? Something to...
  35. R

    Hi everyone,is 'X' be capitalized in 'x-ray'?

    Hi everyone, is 'X' be capitalized in 'x-ray'? i noticed in physics journals, for e.g., in phys. rev. lett., it is not capitalized! which is correct ?? or just it is a matter of personal taste? actually a silly doubt thanks for replying
  36. J

    Medical Can Chest X-Ray Reveal Smoking Damage?

    Chest x-ray? Not my first post, but had to create another username as I forgot my password and apparently there are not 7 letters in the word "physics"...? Anyway, I have smoked about 1/2 pack of cigs a day for about 18 months now. I really regret this, as it was stupid. Will an ordinary...
  37. M

    Some help with a X-Ray astronomy question please

    I've got to solve this problem and I am having quite an hard time figuring out how... Sorry, but I think I need help: "An astronomer takes a spectrum of a distant quasar using a 4m telescope. With an exposure time of one hour, the optical spectrum contains about 10,000 photons. The source...
  38. F

    Calculating actual x-ray flux measurement

    Hi, Hopefully I'm posting this in the correct forum. I'm using Nuclear Associates 07-451 flux detector with a gigaohm input impedance such that the measurement read is logarithmically compressed. The x-ray tube is outputting a constant number of rads. The flux sensor is mounted to the...
  39. D

    Cryogen-cooled x-ray tube anode

    As heat build-up is a major limiting factor in x-ray tube design, why can't the anode be kept at a low base-line temp to reduce heating and limit the potential for structural damage to the target? Does operating the x-ray tube at relatively low temperatures, say zero celsius, affect x-ray...
  40. R

    Cobalt X-ray tube over Copper X-ray tube

    What is the advantage/disadvantage of Cobalt X-ray tube over Copper X-ray tube in a X-Ray diffractometer
  41. M

    Understanding Bragg's Law in X-Ray Diffraction

    We all know, Bragg's law , n\lambda=2dsin\theta where 2dsin\theta=path difference. In the derivation of the path difference we take the two incident rays to be parallel which is perfect BUT we take reflected rays also to be parallel.How can this be since the reflected rays have to MEET for...
  42. N

    X-ray tube and photon energy question?

    Hey all, I am just studying for an upcoming medical imaging exam however I am having some trouble understanding a concept: With regards to X-ray beam production, the effective photon energy of a beam is roughly 60-70% of the maximum photon energy (Emax) at a particular Tube voltage in the...
  43. L

    X-Ray Disappearance Due to Size Effect: A Troubleshooting Guide

    Hi, guys. Did you ever encounter the problem of X-ray disappearing caused by size effect?
  44. T

    Why Does n=2 Not Produce an Equally Strong Peak in X-ray Diffraction?

    1. In satisfying the Bragg's law, n\lambda=2d\sin\theta, n is typically assumed to be one, which explains why we see only one peak for a particular plane (say [400] plane for silicon). But I really don't see why n=2 should not appear as an equally strong peak..? 2. Is the Fourier transform...
  45. Y

    X-ray Fluorescence angle question.

    First of all, I'm not the one doing this experiment. I've just finished my first year in college and I'm sort of just helping all the upper-level with their research and whatnot. So my knowledge is very limited. With that being said, one of those student is doing X-ray Fluorescence. He was...
  46. S

    Which materials are responsible for the peaks in this X-ray diffraction pattern?

    I want to find which elements and planes the intensity peaks in this graph comes from. The X-rays in the diffractometer are have a wavelength of 0.709 Å. The 2 \theta values for the peaks (including double peaks) are: 11.84, 19.56, 20.04, 23.28, 33.88 and 39.16. Nickel, iron, silicon...
  47. S

    X-ray spectroscopy in labs studying Fluorescence

    I did a bit of x-ray spectroscopy in labs studying Fluorescence of some different elements. I was just wondering whether or not flourescence occurs in all elements? I'm sure I've read people talking about 'flourescecnt materials' or something like that. I can't think of any reason why it...
  48. Lisa!

    X-ray Imaging with Anstegrom Wavelengths

    What's the use of X-ray with angestrom wavelengh in imaging? Do you know of any good source to study more about that?
  49. L

    Cuttoff frequwncy for an x-ray tube

    How would you calculate the cutoff frequency of an x-ray tube operating at 44kV? I am using frequency = work function/h. I have (44000eV x 1.602E-19J)/1.626E-34 but my answer is wrong. I'm thinking that I converted kV to eV incorrectly, but I'm not sure. Thanks.
  50. K

    X-ray Diffraction and Bragg's Law

    Homework Statement On a crystal (cubic) a set of diffraction lines (θ) was obtained with CuKα (1.54 Å) radiation: 13.70, 15.89, 22.75, 26.91, 28.25, 33.15, 36.62, 37.60 and 41.95 degrees. Using the following table to determine which peaks are expected to be absent in a cubic P-, I-, and...
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