X-ray Definition and 285 Threads

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...

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...

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

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...

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...

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...

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...

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...

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.

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...

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?

[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?

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...

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...

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.

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

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...

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...

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...

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...

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

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...

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.

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...

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...

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

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...

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...

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...

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...

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...

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...

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...

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...

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!

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...

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...

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...

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

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?

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...

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...

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:

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...

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...

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.

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...

I am curious about a question. in synchrotron station,people use x ray to do kinds of experiments. They use the x ray ,how do they know the characteristic(like wavelength,brightness) of the ray they use. Does they measure the x ray when they use it simultaneously? Does this have an bad effect on...

Hi, Last week I finished M.Sc. degree in Medical Physics. Now I'm pondering what to do next. I have a few questions mainly for Medical Physicsists or Medical Physics Residents: 1. Recently I got very interested in reasearch in the area of the X-ray phase-contrast imaging (PCI). As far as I...

What would happen to the XRD pattern if instead of having spherical atoms, we had triangular atoms? I found the optical diffraction pattern for a triangular aperture, but I'm not sure if optical diffraction patterns would be the same as XRD patterns.