From 99603eedc8f63633ee23d9d8eab49ced242dffc1 Mon Sep 17 00:00:00 2001
From: Alexis Gamelin <alexis.gamelin@synchrotron-soleil.fr>
Date: Fri, 6 Oct 2023 14:19:00 +0200
Subject: [PATCH] Add sample_voltage method to CavityResonator
Bug fix in plot_cavitydata.
New method to sample the voltage seen by a zero charge particle during an RF period.
---
mbtrack2/tracking/monitors/plotting.py | 2 +-
mbtrack2/tracking/rf.py | 51 +++++++++++++++++++++++++-
2 files changed, 51 insertions(+), 2 deletions(-)
diff --git a/mbtrack2/tracking/monitors/plotting.py b/mbtrack2/tracking/monitors/plotting.py
index 8adbae4..d59d359 100644
--- a/mbtrack2/tracking/monitors/plotting.py
+++ b/mbtrack2/tracking/monitors/plotting.py
@@ -1132,7 +1132,7 @@ def plot_cavitydata(filename, cavity_name, phasor="cavity",
units = [" voltage [MV]", " voltage [MV]", " voltage [MV]", " current [A]"]
units_val = [1e-6, 1e-6, 1e-6, 1]
- if plot_type == "bunch" or "mean":
+ if plot_type == "bunch" or plot_type == "mean":
if plot_type == "bunch":
data = [cavity_data["cavity_phasor_record"][bunch_number,:],
diff --git a/mbtrack2/tracking/rf.py b/mbtrack2/tracking/rf.py
index 7afa2dc..0e4287e 100644
--- a/mbtrack2/tracking/rf.py
+++ b/mbtrack2/tracking/rf.py
@@ -185,6 +185,8 @@ class CavityResonator():
Return the generator voltage minus beam loading voltage.
update_feedback()
Force feedback update from current CavityResonator parameters.
+ sample_voltage()
+ Sample the voltage seen by a zero charge particle during an RF period.
References
----------
@@ -923,7 +925,54 @@ class CavityResonator():
for FB in self.feedback:
if isinstance(FB, (ProportionalIntegralLoop, DirectFeedback)):
FB.init_Ig2Vg_matrix()
-
+
+ def sample_voltage(self, n_points=1e4, index=0):
+ """
+ Sample the voltage seen by a zero charge particle during an RF period.
+
+ Parameters
+ ----------
+ n_points : int or float, optional
+ Number of sample points. The default is 1e4.
+ index : int, optional
+ RF bucket number to sample. Be carful if index > 0 as no new beam
+ loading is not taken into account here.
+ The default is 0.
+
+ Returns
+ -------
+ pos : array of float
+ Array of position from -T1/2 to T1/2.
+ voltage_rec : array of float
+ Recoring of the voltage.
+
+ """
+ # Init
+ n_points = int(n_points)
+ index = 0
+ voltage_rec = np.zeros(n_points)
+ pos = np.linspace(-self.ring.T1/2, self.ring.T1/2, n_points)
+ DeltaT = self.ring.T1/(n_points-1)
+
+ # From t=0 of first non empty bunch to -T1/2
+ self.phasor_decay(-self.ring.T1/2 + index*self.ring.T1,
+ ref_frame="beam")
+
+ # Goes from (-T1/2) to (T1/2 + DeltaT) in n_points steps
+ for i in range(n_points):
+ phase = self.m * self.ring.omega1 * (pos[i] + self.ring.T1* (index + self.ring.h * self.nturn))
+ Vgene = np.real(self.generator_phasor_record[index]*np.exp(1j*phase))
+ Vbeam = np.real(self.beam_phasor)
+ Vtot = Vgene + Vbeam
+ voltage_rec[i] = Vtot
+ self.phasor_decay(DeltaT, ref_frame="beam")
+
+ # Get back to t=0
+ self.phasor_decay(-DeltaT*n_points + self.ring.T1/2 - index*self.ring.T1,
+ ref_frame="beam")
+
+ return pos, voltage_rec
+
class ProportionalLoop():
"""
Proportional feedback loop to control a CavityResonator amplitude and phase.
--
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