atsetcavity, identity pass

[simoneliuzzo]

I try to use the legacy mode of atsetcavity.
Setting the voltage to a non zero value, lets the cavity integrator to IdentityPass. See below.

atsetcavity(r_RFstart,50e6,0,harm); % sets RF ON to 50MV and radiation OFF.
ans{1} = 

  struct with fields:

       FamName: 'RFC'
    PassMethod: 'IdentityPass'
        Length: -8.1899e-13
         Class: 'RFCavity'
       Voltage: 12500000
     Frequency: 4.4393e+08
    HarmNumber: 135000
       TimeLag: 0
        Energy: 4.5600e+10

atsetcavity(ring, VOLT, RAD, HARM) used to be a "single function to remember" in order to set the radiation and cavity state of the lattice. Apparently recent updates changed the output of this function.

[lfarv]

Hi @simoneliuzzo
Can you tell what you expected ? and give more details on you lattice: how many cavities in the cell, and how many cells in the ring ?

[simoneliuzzo]

Dear @lfarv,

atsetcavity used to give me a lattice with the features requested by the input:

new_ring = atsetcavity(r_RFstart,50e6,0,harm)

new_ring has

• RF votlage set to 50e6 V evenly shared among cavities.
• cavities on, RFCavityPass
• radiation off (no RadPass and phase 0.0 in the cavities)

the lattice is a proposal for the FCC-ee Z lattice, it has 168 cells, 4 dogleg sections with RF cavities and 4 final focus sections.

best regards
Simone

[lfarv]

From what I see in the history, with radflag=0 as in you example, atsetcavity has always left the cavity pass unchanged, back to the the initial version (Boaz Nash, 2014). The atradon call appeared in 2015 (Simone Liuzzo, 2015), only when radflag in 1. Unless I missed something…

So could you be more precise on what is wrong in your example ? For voltage, frequency and harm, I miss the data !

[lfarv]

Ok. I found what I missed for radflag=0: atradoff(ring, 'CavityPass'): very strange, but does indeed turn on cavities. I will correct that.

[simoneliuzzo]

It looks as my mistake then. Apparently I am setting IdentityPass somewhere before.

However I think CavityPass was set by atsetcavity for radiation off case, for example here at line 38:
https://github.com/atcollab/at/blob/e4847427d135295a7b5fb28f82912ad1db0b6b6d/atmat/atphysics/LongitudinalDynamics/atsetcavity.m

May be I am wrong.

best regards
Simone

[lfarv]

Got it 1 mn before you ! Anything else wrong ?

[lfarv]

Simone, You should have the corrected version in the master and exact_pass branches Laurent

…

On 6 Feb 2023, at 09:47, simone liuzzo ***@***.***> wrote: It looks as my mistake then. Apparently I am setting IdentityPass somewhere before. However I think CavityPass was set by atsetcavity for radiation off case, for example here at line 38: https://github.com/atcollab/at/blob/e4847427d135295a7b5fb28f82912ad1db0b6b6d/atmat/atphysics/LongitudinalDynamics/atsetcavity.m <https://github.com/atcollab/at/blob/e4847427d135295a7b5fb28f82912ad1db0b6b6d/atmat/atphysics/LongitudinalDynamics/atsetcavity.m> May be I am wrong. best regards Simone — Reply to this email directly, view it on GitHub <#557 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AEY4D2OQDUJM7XCBCXTWLYLWWC3CZANCNFSM6AAAAAAURYDAMU>. You are receiving this because you were mentioned.