Questions tagged [x-rays]
Use this tag for question related to X-rays which are a form of high energy electromagnetic radiation having wavelength ranging from 0.1 to 10 nanometres. Also referred to as Röntgen radiation after the scientist who discovered it. X-rays have a range of application including medical CT, airport security, astronomy, crystallography, etc. Different applications use different parts of the X-ray spectrum.
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Debye-Waller Factor in the case of isotropic fluctuations
I am reading through Girvin & Yang Ch. 6 (pg. 91), they mention that the Debye-Waller factor
$$-2\Gamma(\vec{q})=-\langle\langle(\vec{q}\cdot\vec{u}_j)^2\rangle\rangle$$
(where the positions of ...
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Adjectives regarding interfaces
I'm studying X-Ray reflectivity at interfaces and the book I'm reading reads:
... The ideally flat, but graded interface, and the ideally sharp, but roughened interface, will be considered...
I'm ...
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X-ray unit analysis
A survey meter is used to measure X-ray scatter radiation coming through a wall from an adjacent X-ray room. During the test X-ray pulse, the survey meter simultaneously meassures the “accumulated ...
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Kramer's Equation at max Energy for photons is giving Intensity = 0, how is this possibe?
IE = KZ(Em – E)
where IE is the intensity of photons with energy E, Z is the atomic number of the target, Em is the maximum photon energy, and K is a constant. As pointed out earlier, the maximum ...
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When X-ray produced why 99% of the energy is in the form of heat and 1% in the form of X-rays. Why it it not more then that?
When the electrons hit the anode in an X-ray tube, 99% of their energy is released in the form of heat and 1% of that energy is X-rays. Why it is only 1% and not 2% or 3%?
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Is it possible for microwave beam to pass through non-metalic materials?
Greetings fellow physicists. I have some questions about the ability of different electromagnetic waves to pass through materials that I hope you can clarify.
It seems that microwaves can go through ...
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Are their pairs of Nuclear Isobars that differ in energy by less then the Lighter Nuclides Characteristic X-ray?
Isobars are atoms (nuclides) of different chemical elements that have the same number of nucleons.
According to the https://en.wikipedia.org/wiki/Mattauch_isobar_rule if you have two adjacent elements ...
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Gamma Spectroscopy Scintillator for X-ray Fluorescence
I have been reading into X-ray and gamma spectroscopy. I have found that they can both be done with scintillation detectors and work off similar principles.
That is to say that when a sample is ...
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Gamma and X-Ray Shielding with Photoelectric Effect
The photoelectric effect is most probably seen when the incoming light has lower energy than the energy needed for both Compton scattering and pair production to happen.
The probability of the ...
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What's the maximum thrust-to-power ratio of the most possibly powerful absorbed x-ray?
What's the maximum thrust-to-power ratio of the most possibly powerful absorbed x-ray?
In Newtons per watt..
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Energy of an x-ray generated by cathode ray
I'm trying to understand if I could capture the event of generation of an electron positron pair from a gamma ray inside a cloud chamber. So far I've been thinking of using a cathode ray tube as a ...
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Cherenkov radiation in glass via electron tube?
Recently I was experimenting with an vacuum tube attached to a wimshurst machine and measuring the X-Rays emissions. While doing so, I noticed the the surface of the tube began to glow blue in some ...
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Governing equation for white X-ray emission spectra and relation to the BB spectra
The white x-ray spectra (bremsstrahlung radiation) when plotted for different incident electron energies in the same graph, looks very similar to the Black-body radiation curve except for starting ...
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How would we create a device to detect communication using the x-ray and gamma bandwidth? Like a radio. But x-ray gamma spectrum [closed]
I realize the dipole would have to be small enough (in the nucleus of an atom range) and we don't have any mechanism that is small enough to demodulate the frequencies at this rate. But is there some ...
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Why are CT scans much smaller than the raw data?
I'm not too familiar with CT, but I worked with medical CT images long ago, and recall that the raw data, recorded by the scanner was way bigger than the 3D image itself (Both were 16-bit TIFF files, ...
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Medical X-Ray Tube Energy
Is there any way to calculate the mean energy of emitted x-rays in kev if the source have voltage of 140 kV and current is 1.25 mA?
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Formula for amplitude of X-ray diffraction through crystal
I’m an undergrad currently writing a report on a lab we’ve done using X-ray diffraction to look into the structure of crystals. We’ve been told that the structure factor of an element relates to the ...
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Why is Aluminium and Magnesium used as anodes in X-ray sources for X-ray Photoelectron Spectroscopy (XPS)?
Is there any particular reason for using Al/Mg Kα rays in X-Ray Photoelectron Spectroscopy?
I read that the energy of the X-Rays produced by taking these elements as the anode materials can decrease ...
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Luminescence vs. X-ray emission
When a target atom is struck by some kind of radiation (for example, a $\text{MeV}$ proton), electrons from lower shells are kicked off and replaced by electrons from higher shells, which in return ...
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Intensity as a function of selected energy by a crystal monochromator simulation data is different from experimental data
As explained in the above, with a ray tracing Monte carlo simulation software, I record the intensity as a function of the energy I chose to select with a crystal monochromator after the beam has been ...
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How to calculate the resolution of spectrometer at the emission edge of a metal in x-ray emission?
I wonder how I can calculate the resolution of the spectrometer from the Al L2,3 X-ray emission edge, and why this method is used to determine the resolution.
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Why are characteristic X-rays produced in greater numbers than bremsstrahlung rays?
In a typical X-ray spectrum we can observe that characteristic X-rays occur in noticeably larger numbers compared to other energies.
Characteristic emission is a separate phenomenon from ...
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How the braking radiation fit into the photon picture of light?
The continuous part of the x ray spectrum is due the deceleration of electrons. I know that a decelerating charged particle emits a braking radiation according the EM theory. However, what's in the ...
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Why is Copper ($\rm Cu$) better than Molybdenum anode for X-Ray diffraction?
I work in a physics lab, and the project I am working on includes X-Ray (Bragg) diffraction using $\rm NaCl$ single crystal and powdered sample. My professor said that changing the anode of the X-Ray ...
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How to convert bandwidth from wavelength to energy?
I have an x-ray emission spectrum obtained using wavelength dispersive spectroscopy (WDS), the spectrum gives us the number of counts (intensity) as a function of wavelength. I measured the bandwidth (...
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Recombination of protons in solar wind
All accounts of solar wind I have seen (I am no expert in the topic), seem to refer to it being everywhere a plasma (mainly composed of protons/electrons). For example, I have seen statements about ...
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How does CT imaging deal with the thickness of materials?
In the medical CT imaging field, image of an inspected object is obtained through xray projection. xray is attenuated by the inspected object through the formula $I=I_0e^{-\mu t}$. The projection $p$ ...
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What is the mass absorption coefficient and how it is determined?
I would like to know what is mass absorption coefficient in the field of x-ray spectroscopy means and how can we determine this value experimentally (or by simulation) and also why for some materials ...
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Why does the Bremsstrahlung radiation intensity decrease linearly with photon energy?
Why does the spectrum for Bremsstrahlung radiation decrease linearly with photon energy after a certain point (50 keV in the plot)?
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Why are $K_{\alpha}$ and $K_{\beta}$ emissions denoted by $\alpha$ and $\beta$?
Perhaps this is a silly question, but is there any reason for the labelling of $K$ emissions as alpha and beta? From what I know, all $K$ emissions relate to an electron transition down to the $n=1$ ...
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How to treat the thickness of materials in dual energy computed tomography (CT)? [duplicate]
In computed tomography (CT) imaging, the dual energy CT extracts the mass density of two materials based on linear mass attenuation. With two measurements at two different energy, the dual CT can ...
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Why does absorbed dose increase with increasing tube potential in computed tomography?
In X-ray radiography it is a common technique to reduce patient absorbed dose by increasing the X-ray tube potential (kVp) while keeping the detector exposure constant by decreasing the tube current-...
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Length of light burst of concentrated emission from hydrogen bomb in outer space
Imagine a large hydrogen bomb in outer space. Behind it is a huge mylar parabolic mirror. (Aimed anywhere, for instance at a star system we want to communicate with.)
The bomb is placed in the focus ...
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How do X-rays cause fusion?
I have watched the news of the recent fusion experiments and had a question.
I understand that X-rays will make the electrons break away from the atom, because the electons absorb energy.
All of the ...
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Where is the 2.05 MJ input energy measured? (referring to the recent experiment at the National Ignition Facility (NIF))
The recent fusion experiment at the National Ignition Facility delivered "2.05 megajoules (MJ) of energy to the target, resulting in 3.15 MJ of fusion energy output." But where exactly is ...
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Calculating the Miller Indices for the Crystal Structure of Graphite
I am currently completing a lab project on X-Ray Crystallography where I am investigating the crystal structure of graphite.
We are given this relation (1) between the lattice constant $a$ and the ...
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Electrons after Bremsstrahlung radiation
Where do electrons go after they have been braked in the Bremsstrahlung effect? In particular, those who have lost almost all their kinetic energy, could they be captured or interact with the nuclei?
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Derivation of Moseley's Law
I've been going around Moseley's law for characteristic emission of X-rays. Everything up to the derivation seems straight-forward, but I cannot see the sense in the explanation for the $(Z-1)$, that ...
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Characteristic X rays
How do the atom in the target (in the x ray production experiment) go to the normal state if the accelerated electron (from the cathode) knocks a k-electron out the atom and L-electron jumps to fill ...
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Why X-ray imaging base on photon counting is more quick than traditional energy integral detector?
photon counting based on detector can be used to x-ray imaging in industrial pubilc security. In traditional, people often use energy integral scintillation detecor to imaing object through x-ray. The ...
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How to describe the physics process of scintillation? [closed]
I want to find some references on describing the physics of scintillation. As we know the lights generated by scintillator through atom activation and de-activation, and each material has a
spectrum ...
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Why does the intensity of the escape peak from an Am-241 gamma ray seem to change based on the element placed in front of the Am source?
I am trying to measure the value of Germanium's $K_{\alpha}$ x-ray by measuring the escape peaks produced by an Amersham $Am^{241}$ source x-ray striking a Germanium x-ray detector. The Amersham ...
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Questions about creating diffraction grating
I have a modern physics lab project this semester where we have to perform an experiment related to modern physics as a group of 3.
We choose https://aapt.scitation.org/doi/10.1119/1.5020051, an ...
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What is the input of calculating signal noise ratio (SNR) and detective quantum efficiency (DQE) in estimation of imaging system?
In its definition, the signal noise ratio (SNR) is the ratio of the mean siganl to the standard deviation of the noise. However, for a given picture what is the noise? The detective quantum efficiency ...
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Production of X-Rays for crystallography
X-Ray diffraction is an important tool for determining the crystal structure of a sample. I believe that monochromatic X-Ray beams are necessary for this kind of experiments, since diffraction ...
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How can the waves interfere in X-ray diffraction?
This is the popular diagram surrounding the Bragg's law for X ray diffraction:
But what I seem to not be able to understand is when they say that the reflected waves interact constructively to create ...
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How to interpret XRD results?
I am given several datapoints of XRD strain information. It comes from XRD measurement of a thin layer (100 nm) of semiconductor deposited on top of another semiconductor.
The result I'm given is ...
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Doubt about collision in characteristic x-rays
Recently I was studying characteristic x-rays and their process of emission, but I don’t understand why the ejected electron of the atom belongs always to the inner shell. Couldn’t the emitted ...
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Can X-rays travel quicker than visible light in a medium?
I have seen while reading a few books that the refractive index depends on lambda as follows by the Cauchy equation.
$${\displaystyle \eta(\lambda )=A+{\frac {B}{\lambda ^{2}}}}$$
From this, the book ...
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Reducing the filament voltage has no effect on the maximum photon energy produced by characteristic or Bremsstrahlung radiation. TRUE - why?
I'm studying for my radiology exams and I don't understand the answer to this question.
It states that the following sentence is true:
Reducing the filament voltage has no effect on the maximum ...
