LHC.py

from PyMachines.synchrotron import BasicSynchrotron
import numpy as np
from scipy.constants import c, e, m_p

class LHC(BasicSynchrotron):

	def __init__(self, machine_configuration=None, optics_mode='smooth', **kwargs):
		
		
		longitudinal_mode = 'non-linear' 
		alpha		= 3.225e-04
		h_RF       	= 35640
		mass 		= m_p
		charge		= e
		
		if machine_configuration=='Injection':
			p0 			= 450e9 * e /c
			p_increment = 0.
			accQ_x		= 64.28
			accQ_y		= 59.31
			V_RF		= 6e6
			dphi_RF		= 0.
		elif machine_configuration=='6.5_TeV_collision_tunes':
			p0 			= 6500e9 * e /c
			p_increment = 0.
			accQ_x		= 64.31
			accQ_y		= 59.32
			V_RF		= 12e6
			dphi_RF		= 0.
		else:
			raise ValueError('machine_configuration not recognized!')
			
		
		
		if optics_mode=='smooth':
			if 's' in kwargs.keys(): raise ValueError('s vector cannot be provided if optics_mode = "smooth"')
			
			n_segments = kwargs['n_segments']
			circumference = 26658.8832
			
			name = None
			
			beta_x 		= 92.7 
			D_x 		= 0
			beta_y 		= 93.2 
			D_y 		= 0 
			
			alpha_x 	= None
			alpha_y 	= None
			
			s = None
			
		elif optics_mode=='non-smooth':
			if 'n_segments' in kwargs.keys(): raise ValueError('n_segments cannot be provided if optics_mode = "non-smooth"')
			n_segments = None
			circumference = None
			
			name		= kwargs['name']
			
			beta_x 		= kwargs['beta_x']
			beta_y 		= kwargs['beta_y'] 

			try:
				D_x 		= kwargs['D_x']	
			except KeyError:
				D_x 		= 0*np.array(kwargs['s'])
			try:
				D_y 		= kwargs['D_y']	
			except KeyError:
				D_y 		= 0*np.array(kwargs['s'])			
					
			alpha_x 	= kwargs['alpha_x']
			alpha_y 	= kwargs['alpha_y']
			
			s = kwargs['s']
		
		else:
			raise ValueError('optics_mode not recognized!')		

		
		# detunings
		Qp_x		= 0
		Qp_y		= 0
		
		app_x		= 0
		app_y		= 0
		app_xy		= 0
		
		i_octupole_focusing = None
		i_octupole_defocusing = None
		octupole_knob = None	
		
		for attr in kwargs.keys():
			if kwargs[attr] is not None:
				if type(kwargs[attr]) is list or type(kwargs[attr]) is np.ndarray:
					str2print = '[%s ...]'%repr(kwargs[attr][0])
				else:
					str2print = repr(kwargs[attr])
				self.prints('Synchrotron init. From kwargs: %s = %s'
							% (attr, str2print))
				temp =  kwargs[attr]
				exec('%s = temp'%attr)
				


		if i_octupole_focusing is not None or i_octupole_defocusing is not None:
			if octupole_knob is not None:
				raise ValueError('octupole_knobs and octupole currents cannot be used at the same time!')
			app_x, app_y, app_xy = self._anharmonicities_from_octupole_current_settings(i_octupole_focusing, i_octupole_defocusing)
			self.i_octupole_focusing = i_octupole_focusing
			self.i_octupole_defocusing = i_octupole_defocusing
			
		if octupole_knob is not None:	
			if i_octupole_focusing is not None or i_octupole_defocusing is not None:
				raise ValueError('octupole_knobs and octupole currents cannot be used at the same time!')
			i_octupole_focusing, i_octupole_defocusing =  self._octupole_currents_from_octupole_knobs(octupole_knob, p0)
			app_x, app_y, app_xy = self._anharmonicities_from_octupole_current_settings(i_octupole_focusing, i_octupole_defocusing)		
			self.i_octupole_focusing = i_octupole_focusing
			self.i_octupole_defocusing = i_octupole_defocusing
		
		
		super(LHC, self).__init__(optics_mode=optics_mode, circumference=circumference, n_segments=n_segments, s=s, name=name,
             alpha_x=alpha_x, beta_x=beta_x, D_x=D_x, alpha_y=alpha_y, beta_y=beta_y, D_y=D_y,
             accQ_x=accQ_x, accQ_y=accQ_y, Qp_x=Qp_x, Qp_y=Qp_y, app_x=app_x, app_y=app_y, app_xy=app_xy,
             alpha_mom_compaction=alpha, longitudinal_mode=longitudinal_mode,
             h_RF=np.atleast_1d(h_RF), V_RF=np.atleast_1d(V_RF), dphi_RF=np.atleast_1d(dphi_RF), p0=p0, p_increment=p_increment,
             charge=charge, mass=mass)
		
	def _anharmonicities_from_octupole_current_settings(self, i_octupole_focusing, i_octupole_defocusing):
			"""Calculate the constants of proportionality app_x, app_y and
			app_xy (== app_yx) for the amplitude detuning introduced by the
			LHC octupole magnets (aka. LHC Landau octupoles) from the
			electric currents i_octupole_focusing [A] and i_octupole_defocusing [A] flowing
			through the magnets. The maximum current is given by
			i_max = +/- 550 [A]. The values app_x, app_y, app_xy obtained
			from the formulae are proportional to the strength of detuning
			for one complete turn around the accelerator, i.e. one-turn
			values.
			The calculation is based on formulae (3.6) taken from 'The LHC
			transverse coupled-bunch instability' by N. Mounet, EPFL PhD
			Thesis, 2012. Values (hard-coded numbers below) are valid for
			LHC Landau octupoles before LS1. Beta functions in x and y are
			correctly taken into account. Note that here, the values of
			app_x, app_y and app_xy are not normalized to the reference
			momentum p0. This is done only during the calculation of the
			detuning in the corresponding detune method of the
			AmplitudeDetuningSegment.
			More detailed explanations and references on how the formulae
			were obtained are given in the PhD thesis (pg. 85ff) cited
			above.
			"""
			i_max = 550.  # [A]
			E_max = 7000. # [GeV]
	
			app_x  = E_max * (267065. * i_octupole_focusing / i_max -
				7856. * i_octupole_defocusing / i_max)
			app_y  = E_max * (9789. * i_octupole_focusing / i_max -
				277203. * i_octupole_defocusing / i_max)
			app_xy = E_max * (-102261. * i_octupole_focusing / i_max +
				93331. * i_octupole_defocusing / i_max)
	
			# Convert to SI units.
			convert_to_SI = e / (1.e-9 * c)
			app_x *= convert_to_SI
			app_y *= convert_to_SI
			app_xy *= convert_to_SI
	
			return app_x, app_y, app_xy
		
	def _octupole_currents_from_octupole_knobs(self, octupole_knob, p0):
		i_octupole_focusing = 19.557 * octupole_knob / (-1.5) * p0 / 2.4049285931335872e-16
		i_octupole_defocusing = - i_octupole_focusing
		return i_octupole_focusing, i_octupole_defocusing