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[Opal] OPAL and cavity phase


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  • From: Wolf-Dieter Klotz <wdklotz AT gmail.com>
  • To: opal AT lists.psi.ch
  • Subject: [Opal] OPAL and cavity phase
  • Date: Wed, 30 Nov 2022 14:02:41 +0100
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Hi Mr.Adelmann
I am puzzeled by the way OPAL handles the phasing of cavities. I have a linear lattice setup with arrays of independent single gap pillbox cavities. My cavity is defined like this:
RFG1: RFCavity, L=0.024, VOLT=6.4, TYPE="SINGLEGAP", FMAPFN="OPALEzTab1", FREQ=816.0, LAG=(-25.0*Pi)/180.0, APVETO=False;
If I set autophasing on (1 in this case) I get the following Ez-field on the axis and final kinectic energy:
image.png

image.png

However if I set APVETO to True like that:
RFG1: RFCavity, L=0.024, VOLT=6.4, TYPE="SINGLEGAP", FMAPFN="OPALEzTab1", FREQ=816.0, LAG=(-25.0*Pi)/180.0, APVETO=True;
I get instead (what I don't understand):
image.png

image.png

The first case seems to me to be correct from what I expect from the physics. Equal increments in energy and always positive field in the cavities.
But I gave a LAG=-25.0 degrees as synchronous phase and expected something similar in the second case.

How can this be explained and how can I see what phases autophasing is producing and why does it not work with autophasing off?
Best regards...
Wolf-Dieter Klotz

27, Route du Ch√Ęteau
38640 CLAIX, France
+33 [0]6 87 38 59 27
wdklotz AT gmail.com




  • [Opal] OPAL and cavity phase, Wolf-Dieter Klotz, 11/30/2022

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