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#37
Apr408, 04:53 AM

P: 908




#38
Apr708, 02:59 PM

P: 908

Astronuc, please answer me, my last question...



#39
Apr708, 03:17 PM

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Physicsissuef: you can find the forumulas (and how to derive them) for the betaprobablity distribution in Kranes nuclear textbook  Introductory Nuclear Physics.



#40
Apr708, 06:19 PM

P: 12

Beta emission, may vary from a radionuclide to another but in general the energy distribution graph looks like the same for every radionuclide, apart for the maximum energy.
The spectrum of the Beta emission is continuos due to the random ripartition of momentum and energy betwen neutrino. Energy distribution for Bemission of P32 


#41
Apr808, 01:49 AM

P: 908

So there are only 2 kinetic energies for every nuclei?



#42
Apr808, 04:30 AM

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NO! There exists an energy distribution, which is quite similar for each nucleus. You nay want to look for the derivation of this distribution shape, see for instance the reference i gave you. 


#43
Apr808, 05:14 AM

P: 908

Why there are 2 points M_1 and M_2 is my question??



#44
Apr808, 05:27 AM

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Perhaps you should google 'probability distribution' to learn more about this concept. 


#45
Apr808, 05:36 AM

Admin
P: 21,887

Draw an inverted parabola, and one would see that for each y there are two values of x, except for the maximum value of which there is one. There is a continuum of energies (between 0 and E_{max}), and E_{max} is an upper limit. 


#46
Apr808, 05:51 AM

P: 908

I mean, how is possible for one value of beta particles, to have 2 values for the kinetic energy of the electrons?



#47
Apr808, 05:55 AM

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now you are just writng things I cant understand.. check your english.
on your yaxis you have the NUMBER of electrons emitted. On the xaxis you have their energy. Please check 'probability distribution function' on google, I think you need this. Every beta particle has just ONE value of Energy, but what energy  and the fraction of the beta particles who has a perticular energy is given by the distribution function. 


#48
Apr808, 06:10 AM

P: 908

On the xaxis I have number of beta particles, and on the yaxis I have the kinetic energy of electrons...



#49
Apr808, 06:17 AM

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P: 21,887

By convention, in Cartesian coordinates yaxis is vertical and xaxis is horizontal when looking. 


#50
Apr808, 06:17 AM

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No. please look at your images again.
y axis goes up, x axis goes to the right. It is the most used convention. 


#51
Apr808, 12:22 PM

P: 908

Yes, sorry it was typo. So how is possible that for one value of beta particles, to have 2 kinetic energies for the electrons?



#52
Apr808, 02:08 PM

P: 12

It's statistic!!!
A single electron can't have 2 different energy at the same time, but on a population of milion of electrons emitted by that radionuclide you will know how many ( % ) got a E1 energy and how many got E2 energy and so on from 0 to Emax. I.E. if you use a distribution of human population weight, you can have that 20% of them that weight "A" Kg and another 20% that weight "B" kg , but that dosen't mean that you have a man that weight both "A" kg and "B" kg at the same time. 


#53
Apr808, 03:24 PM

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beta particle = electron, same thing, different names.. And it is a PROBABILITY DISTRIBUTION. The figures you have is a distrubtion cure where one has plotted the number of electrons with repsect to their energy. To obtain this figure, one has recorded several milions of betaparticles. So each electron has ONE value of kinetic energy, and several electrons can have the same kinetic energy. 


#54
Apr808, 04:33 PM

P: 12

Ah yes i'm sorry, statistic is another thing...sorry again for my italian interpretaion of english words.



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