search

MethodicalAcceleratorDesign / MAD-X

MAD-X repository
Other
49 stars 39 forks source link

Could Mad-x create the Twiss file with rotation alignment error? #1099

Closed LiarGC closed 2 years ago

LiarGC commented 2 years ago

I tried to add an alignment error to a sextupole. Firstly I gave it a position alignment error: EALIGN, DS := 5e-4*TGAUSS(2); The "L" of this sextupole in the Twiss file changed correctly.

But when adding the rotation misalignment: EALIGN, DS := 5e-4*TGAUSS(2), DPSI := 5e-4*TGAUSS(2); The "K2SL" of this sextupole in the Twiss file was 0, while the "K2L" was still its original value.

I saved and checked the error file, finding no problem with the rotation misalignment. And I tried the PTC_TWISS function, which gave the same result, "K2SL"=0.

Did I miss some key word to include the rotation misalignment?

LiarGC commented 2 years ago

There is one mistake, The "L" didn't change either, only the twiss parameters, such as BetaX, BetaY, changed.

rdemaria commented 2 years ago

Twiss stable contains the attributes of the element without taking into account the imperfections defined by EALIGN or EFCOMP. The imperfections can be retrieved using the ESAVE, but also in this case you will get rotations and multipoles error separated.