How much energy is required to produce the electronpositron pair ...by vst98 Tags: electronpositron, energy, pair, produce, required 

#1
Feb2512, 04:09 PM

P: 32

1. The problem statement, all variables and given/known data
How much energy is required to produce the electronpositron pair in the filed of nucleus (Z=20) if electron is captured to the ground 1s state of the system. 3. The attempt at a solution I can calculate the energy of the captured electron from E =  εZ^{2}/(2n^{2}) where ε=me^{4}/hbar^{2}≈27.2eV E =  5442eV Now I have to add this energy to the energy of created positron to have total required energy, right ? But I do not know how to find energy of a positron. 



#2
Feb2512, 04:44 PM

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P: 26,167

hi vst9!




#3
Feb2612, 03:03 PM

P: 32

hi tinytim !
Yes I think so, then it is the energy and momentum conservation that places a restriction on the positron to have the same energy as electron , right ? I was a little bit confused by the "... in the filed of nucleus" part of the question, then this filed of a nucleus does not change much (except maybe the needed energy). So, the needed energy for pair creation is E=2*5442=10.88keV 



#4
Feb2612, 04:41 PM

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P: 26,167

How much energy is required to produce the electronpositron pair ...
hi vst98!
right! i'm not sure why they mentioned the field (not "filed" ) … it doesn't seem to add anything to the rest of the question 



#5
Feb2712, 05:18 PM

P: 32

Ok, thanks !
(yes it is "field" and not "filed" in the original question, my flip error :) ) 


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