Search found 7 matches

by ChongChong
25 Feb 2019, 03:00
Forum: Optimization and Matching
Topic: tune correction of coupling lattice
Replies: 4
Views: 8354

Re: tune correction of coupling lattice

Dear Michael,

In practice, is it necessary to add special skew quads(how many) for coupling to obtain a round beam? If adding a special skew quad, where is it at APS storage ring, in straight section or somewhere?

Thank you,

Chongchong
by ChongChong
11 Jan 2019, 08:02
Forum: Optimization and Matching
Topic: tune correction of coupling lattice
Replies: 4
Views: 8354

Re: tune correction of coupling lattice

Dear Michael, Thank you for your suggestion, and I follow your example. Question 1:Theoretically, e1=e2=(e10+e20)/2=17.5 pm when I tune the lattice to the difference resonance(where e10 and e20 are initial emittance respectively). But the results (Fig.1) show that e1=e2=23pm. Could you help me solve...
by ChongChong
28 Nov 2018, 22:30
Forum: Optimization and Matching
Topic: tune correction of coupling lattice
Replies: 4
Views: 8354

tune correction of coupling lattice

Hi all, I am correcting the tune to realize the difference resonance (equal fractional betatron tunes)in order to obtain a round beam(emittance x is equal to emittance y) in a coupling lattice, and TWO quad families (Q1,Q2) that correct tunes is recommended. "&correct_tunes " should follow "&twiss_o...
by ChongChong
27 Sep 2018, 10:31
Forum: Ring Tracking
Topic: Emittance statistics about the difference resonance
Replies: 3
Views: 3757

Re: Emittance statistics about the difference resonance

Dear Michael, According to your suggestion, I used the moments_output command in elegant to find the three actual emittances. e1 (m) = 3.420662e-11 e2 (m) = 5.694252e-17 e3 (m) = 5.261045e-06 And I put in several watch elements at different locations, the results are not all the same. Theoretically,...
by ChongChong
24 Sep 2018, 01:36
Forum: Ring Tracking
Topic: Emittance statistics about the difference resonance
Replies: 3
Views: 3757

Emittance statistics about the difference resonance

Dear all, I changed betatron tunes to realize the difference resonance (equal fractional betatron tunes)in order to obtain a round beam(emittance x is equal to emittance y). I used "WATCH" to record the data of emittance x and emittance y for tracking particles in the elegant. But the statistical re...
by ChongChong
24 Sep 2018, 01:30
Forum: Feature Requests
Topic: Coupling integral for sum resonance
Replies: 3
Views: 14221

Re: Coupling integral for sum resonance

Dear Michael and others, I changed betatron tunes to realize the difference resonance (equal fractional betatron tunes)in order to obtain a round beam. I used "WATCH" to record the data of emittance x and emittance y for tracking particles in the elegant. But the statistical results show that emitta...
by ChongChong
17 Oct 2017, 20:56
Forum: Ring Tracking
Topic: space-charge tune shifts effect
Replies: 2
Views: 3558

Re: space-charge tune shifts effect

If we were removing rf cavities and synchrotron radiation, using a beam with no energy spread (to keep fixed bunch length),
how could I accurately count the emittance caused by space-charge effect?