How to scan the position of the quadrupole to measure the emittance

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QinJohn
Posts: 1
Joined: 16 Oct 2017, 07:13

How to scan the position of the quadrupole to measure the emittance

Post by QinJohn » 20 Oct 2017, 08:15

Hi All,
I'm a new to the elegant and I want to simulate the quadrupole scan method to measure the emittance. I have found an example in the ElegantExamples, in that example, the scan parameters are strength of the quadrupoles. Now I want to scan the quadrupoles' position, which can also lead to the change of the transfer matrix. When I change the parameter to the position, the results showed as follows:

Vertical emittance couldn't be determined
Horizontal emittance couldn't be determined
Horizontal emittance couldn't be determined
Vertical emittance couldn't be determined
Vertical emittance couldn't be determined
Horizontal emittance couldn't be determined
Vertical emittance couldn't be determined
Horizontal emittance couldn't be determined
Vertical emittance couldn't be determined
Vertical emittance couldn't be determined

The attachment is my input file .Any one can help me to solve this question? Thank you !
Attachments
one_quad.zip
(1.23 KiB) Downloaded 255 times

michael_borland
Posts: 1796
Joined: 19 May 2008, 09:33
Location: Argonne National Laboratory
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Re: How to scan the position of the quadrupole to measure the emittance

Post by michael_borland » 23 Oct 2017, 09:59

John,

The problem seems to be that this method is very senstive to errors and to the fact that the beam size only goes through a minimum in one plane. I was able to improve matters slightly by using two stronger quadrupoles, see attached. Perhaps this will give a clue.

--Michael
Attachments
2017-10-23.zip
(51.54 KiB) Downloaded 268 times

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