# x-ray Definition and Topics - 30 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. ### I Transmission through flow cell using small-angle x-ray scattering

Hello, I plan to run an experiment using SAXS for in-situ solution phase reaction analysis. We will use a glass micro-fluidic chip due to experimental limitation reasons. I am looking for the optimal path length for these channels (fluid channel depth). My understanding is that we need to...
2. ### Calculate number of photons absorbed

I've tried to solve this by calculating the number of photons. I've done this by calculating the energy of one photon, taking h*c divided by lambda. h*c is 1240 eV*nm and lambda is 10 nm. This gives me 124 eV. I then divide the total energy by the energy of one photon, 50 keV/ 124 = 403 photons...
3. ### I X-ray astronomy

Does any one know the energy distribution of highly charged ions in solar wind or other astrophysical context?
4. ### I Scatter radiation and film fogging

Hello, During the procedure of radiography using x-rays, scatter radiation occurs, due to the difference in densities of the object being radiographed. That scatter radiation causes fogging (noise) of the film, i.e. the contrast of the film is reduced due to extra darkening of some areas of...
5. ### I Why XRD peaks are so sharp?

I was reviewing an old topic for me that's x-ray diffraction, and one doubt I always had in my mind arised again. When introducing the Bragg's law, the typical explanation is that the x-ray waves reflecting in two adjacent planes interfere with each other, leading to a fully constructive...
6. ### I Why are more x-rays made from metal than glass

i know that x-rays are produced when a beam of high energy electrons hits a metal anode but why does that work better than when that same beam hits glass (like in the Crookes tube)? Thanks
7. ### Voltage of thundercloud as point charge

Hey, Theory: The voltage of a thundercloud is too low to ionize air particles and to produce a thunder. Particles of cosmic radiation are the trigger. I calculated whether the voltage of a thundercloud is enough to ionize air particles but the voltage was always to low. So I wanted to know...
8. ### 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...
9. 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?
10. Z

### I What's going on Cs-137

Hey guys, im 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...
11. ### Target element in Coolidge tube and x-rays

Homework Statement Homework Equations The 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?
12. ### 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...
13. ### 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...
14. ### Bragg's Angles for X-Ray

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...
15. ### 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...
16. ### 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...
17. ### X-rays: trouble understanding

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...
18. ### 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...
19. ### 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...
20. ### X-rays physics

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) cant we use high frequency of X-ray ?so that it will penetrate more as tissue are poor absorber...
21. ### 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...
22. ### 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...
23. ### 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}##
24. ### 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...
25. ### 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...
26. ### 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...
27. ### 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...
28. ### 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...
29. ### 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...
30. ### 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