Recent content by deccard

Yes, you are right that when you are making a measurement of a spectra, you should take a background run if possible. This is not always possible, sometimes not even desired, with a real experiment. I've seen, for example, an ion beam mass spectrum that had a peak on every mass visible. I could...

Yes, I should have said that the example data was made using Gaussian distribution. The simulated data is done with Matlab command: poissrnd(ones(1,length(x))*0.4+13*exp(-(x-8.7).^2/(1.89^2))), where the x = 0 to 100 in steps of 1 (x=0:1:100) That means that each bin has background counts...

In principle, if I wanted to get the background only, I could take the counts away from the peak and determine background. Still, there should be a possibility to fit the data so that the background level is included in the fitted profile. I know the uncertainties for each bin. As the number of...

I have one dimensional binned data that has a peak to which I need to fit a distribution, such as Gaussian or Lorentzian, that is described with four parameters, height, width, centroid position and the background. The problem is that the counts per bin are low and the peak is only 5-6 bins wide...

Yes, that is true. But is there something in the SM or some other model that justifies the use of word "point"?

*Ahem*, Yes I mean divide. Thicknesses are many times given in g/cm2 for for example beam target's. This is because the absorption of radiation in a target is dependent on the mass in the target. 2 cm gaseous nitrogen target is very different from 2 cm lead target. Instead of saying that you...

But how does this pointness manifest itself? I mean, I can understand that if, let's say an electron, hits a thin atom layer and makes a hole in it. The size of the hole can be smaller than the "size" of the wave function. Does the pointness only mean that an elementary particle does not...

Try to do the integration by assuming a constant stopping power. The stopping power is different for different alpha energies, but gives at least an estimation of the range. What is the kinetic energy of your alpha particle? You of course cannot make g/cm2 to cm just by changing the unit...

I have been wondering exactly the same thing. Haven't found a answer, though. Just to be clear, it is not about selecting a value of a returned vector, but selecting a specific output. It is especially annoying if I have a multiple output arguments. function [A,B,C,D,E,F] = myFun(inputarg) ...

Now, I am little bit confused. I have started to doubt the permissibility of the two transitions below. (With \right \left| l,m_l,m_s\rangle ) \right \left| 1,0,+1/2\rangle \rightarrow \right \left| 0,0,+1/2\rangle \right \left| 1,0,-1/2\rangle \rightarrow \right \left| 0,0,-1/2\rangle...

I have been trying to picture the whole process of a photon emission by a atom. So to have good understanding what is going on, I have came up with following experimental setup. A single hydrogen atom in excited state ^2\!P_{1/2}, which has been orientated with a magnetic field so that...

Because Claude hasn't answered. Could someone please explain why streetlight cannot have spatial and temporal coherence same time, only one or the other?

Of course it is not. But I got the impression that Claude Bile was talking generally of light waves. But why streetlight cannot have temporal and spatial transverse coherence at the same time? Moreover, how we can have spatial coherence if we do not have temporal coherence in other words...

Maybe the best picture that I have seen showing a plane wave is http://http://en.wikipedia.org/wiki/Image:Onde_plane_3d.jpg" . It shows red planes that represent the maximum of the electric or the magnetic field. The very tops of sine waves in three dimensional space, if you like. But I think...

Why spatial (transverse) coherence cannot exist with temporal coherence? If light is temporally coherent or that is to say it is monochromatic, I don't see why it cannot be spatially coherent. Isn't for example laser light temporally coherent and spatially coherent as well as phase coherent.