From 4109b3df59fd8d6201dc2dafda140c67bab1f937 Mon Sep 17 00:00:00 2001
From: Gamelin Alexis <alexis.gamelin@synchrotron-soleil.fr>
Date: Wed, 2 Aug 2023 18:09:21 +0200
Subject: [PATCH] Improve Synchrotron.synchrotron_tune
Synchrotron.synchrotron_tune can now compute the synchrotron tune for single or multi-harmonic RF systems using linear approximation.
---
mbtrack2/tracking/synchrotron.py | 55 ++++++++++++++++++++++++++------
1 file changed, 45 insertions(+), 10 deletions(-)
diff --git a/mbtrack2/tracking/synchrotron.py b/mbtrack2/tracking/synchrotron.py
index 236f34e..f9b783e 100644
--- a/mbtrack2/tracking/synchrotron.py
+++ b/mbtrack2/tracking/synchrotron.py
@@ -85,8 +85,8 @@ class Synchrotron:
Methods
-------
- synchrotron_tune(Vrf)
- Compute synchrotron tune from RF voltage.
+ synchrotron_tune(V)
+ Compute the synchrotron tune for single or multi-harmonic RF systems.
sigma(position)
Return the RMS beam size at equilibrium in [m].
eta(delta)
@@ -317,23 +317,58 @@ class Synchrotron:
self.optics.dispersion(position)[3]**2*self.sigma_delta**2)**0.5
return sigma
- def synchrotron_tune(self, Vrf):
+ def synchrotron_tune(self, V, phase=None, harmonics=None):
"""
- Compute synchrotron tune from RF voltage
+ Compute the synchrotron tune for single or multi-harmonic RF systems.
+
+ Hypthesis:
+ - Use the linear approximation (tau ~ 0).
+ - For higher haromics only, cos(phi) ~ 0 must be true.
Parameters
----------
- Vrf : float
- Main RF voltage in [V].
+ V : float or array-like of float
+ RF voltage in [V].
+ phase : float or array-like of float, optional
+ RF phase using cosine convention in [rad].
+ Default is None.
+ harmonics : int or array-like of int, optional
+ Harmonics of the cavities to consider.
+ Default is None.
+
+ Usage
+ -----
+ - If a single voltage value is given, compute the synchrotron tune for
+ a single RF system set at the synchronous phase.
+ - If a single pair of voltage/phase value is given, compute the
+ synchrotron tune for a single RF system.
+ - Otherwise, compute the synchrotron tune for a multi-harmonic RF
+ system.
Returns
-------
tuneS : float
- Synchrotron tune.
+ Synchrotron tune in the linear approximation.
"""
- phase = np.pi - np.arcsin(self.U0 / Vrf)
- tuneS = np.sqrt( - (Vrf / self.E0) * (self.h * self.ac) / (2*np.pi)
- * np.cos(phase) )
+
+ if isinstance(V, float) or isinstance(V, int):
+ V = [V]
+ if phase is None:
+ phase = [np.arccos(self.U0/V[0])]
+ elif isinstance(phase, float) or isinstance(phase, int):
+ phase = [phase]
+ if harmonics is None:
+ harmonics = [1]
+
+ if not (len(V) == len(phase) == len(harmonics)):
+ raise ValueError("You must provide array of the same length for"
+ " V, phase and harmonics")
+
+ Vsum = 0
+ for i in range(len(V)):
+ Vsum += harmonics[i] * V[i] * np.sin(phase[i])
+ phi = np.arccos(1 - self.eta(0) * np.pi * self.h / self.E0 * Vsum)
+ tuneS = phi / (2 * np.pi)
return tuneS
def get_adts(self):
--
GitLab