opal AT lists.psi.ch

Subject: The OPAL Discussion Forum

List archive

[Opal] Fwd: OPAL and cavity phase

From: Wolf-Dieter Klotz <wdklotz AT gmail.com>
To: opal AT lists.psi.ch
Subject: [Opal] Fwd: OPAL and cavity phase
Date: Tue, 29 Nov 2022 17:08:15 +0100
Authentication-results: mc2.ethz.ch; iprev=pass (mail-pg1-f173.google.com) smtp.remote-ip=209.85.215.173; spf=pass smtp.mailfrom=gmail.com; dkim=pass header.d=gmail.com header.s=20210112 header.a=rsa-sha256; dmarc=pass header.from=gmail.com

---------- Forwarded message ---------
From: Wolf-Dieter Klotz <wdklotz AT gmail.com>
Date: Tue, Nov 29, 2022 at 10:53 AM
Subject: OPAL and cavity phase
To: Adelmann Andreas (PSI) <andreas.adelmann AT psi.ch>

Hi Mr.Adelann

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:

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):

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 Château
38640 CLAIX, France
+33 [0]6 87 38 59 27
wdklotz AT gmail.com

[Opal] Fwd: OPAL and cavity phase, Wolf-Dieter Klotz, 11/29/2022