at.acceptance.touschek#

Module to compute the touschek lifetime of the ring

Functions

`get_bunch_length_espread`(ring[, zn, ...])	Haissinski equation solver
`get_lifetime`(ring, emity, bunch_curr[, ...])	Touschek lifetime calculation
`get_scattering_rate`(ring, emity, bunch_curr)	Touschek scattering rate calculation

get_bunch_length_espread(ring, zn=None, bunch_curr=None, espread=None)[source]#

Haissinski equation solver

Solves the Haissinski formula and returns the bunch length and energy spread for given bunch current and \(Z/n\). If both zn and bunch_curr are None, zero current case, otherwise both are needed for the calculation

Parameters:

ring – ring use for tracking

Keyword Arguments:

zn=None – \(Z/n\) for the full ring
bunch_curr=None – Bunch current
espread=None – Energy spread, if None use lattice parameter

Returns:

Bunch length, energy spread

get_lifetime(ring, emity, bunch_curr, emitx=None, sigs=None, sigp=None, zn=None, momap=None, refpts=None, offset=None, **kwargs)[source]#

Touschek lifetime calculation

Computes the touschek lifetime using the Piwinski formula

Parameters:

ring – ring use for tracking
emity – verticla emittance
bunch_curr – bunch current

Keyword Arguments:

emitx=None – horizontal emittance
sigs=None – rms bunch length
sigp=None – energy spread
zn=None – full ring \(Z/n\)
momap=None – momentum aperture, has to be consistent with refpts if provided the momentum aperture is not calculated
refpts=None – refpts where the momentum aperture is calculated, the default is to compute it for all elements in the ring, len(refpts)>2 is required
resolution – minimum distance between 2 grid points, default=1.0e-3
amplitude – max. amplitude for RADIAL and CARTESIAN or initial step in RECURSIVE default = 0.1
nturns=1024 – Number of turns for the tracking
dp=None – static momentum offset
offset – initial orbit. Default: closed orbit
grid_mode – at.GridMode.CARTESIAN/RADIAL track full vector (default). at.GridMode.RECURSIVE: recursive search
use_mp=False – Use python multiprocessing (patpass, default use lattice_pass). In case multi-processing is not enabled GridMode is forced to RECURSIVE (most efficient in single core)
verbose=False – Print out some inform
epsrel (epsabs,) – integral absolute and relative tolerances

Returns:

tl – touschek lifetime, double expressed in seconds
ma – momentum aperture (len(refpts), 2) array
refpts – refpts used for momentum aperture calculation (len(refpts), ) array

get_scattering_rate(ring, emity, bunch_curr, emitx=None, sigs=None, sigp=None, zn=None, momap=None, refpts=None, offset=None, **kwargs)[source]#

Touschek scattering rate calculation

Computes the touschek scattering using the Piwinski formula

Parameters:

ring – ring use for tracking
emity – verticla emittance
bunch_curr – bunch current

Keyword Arguments:

emitx=None – horizontal emittance
sigs=None – rms bunch length
sigp=None – energy spread
zn=None – full ring \(Z/n\)
momap=None – momentum aperture, has to be consistent with refpts if provided the momentum aperture is not calculated
refpts=None – refpts where the momentum aperture is calculated, the default is to compute it for all elements in the ring, len(refpts)>2 is required
resolution – minimum distance between 2 grid points, default=1.0e-3
amplitude – max. amplitude for RADIAL and CARTESIAN or initial step in RECURSIVE default = 0.1
nturns=1024 – Number of turns for the tracking
dp=None – static momentum offset
grid_mode – at.GridMode.CARTESIAN/RADIAL track full vector (default). at.GridMode.RECURSIVE: recursive search
use_mp=False – Use python multiprocessing (patpass, default use lattice_pass). In case multi-processing is not enabled GridMode is forced to RECURSIVE (most efficient in single core)
verbose=False – Print out some inform
epsrel (epsabs,) – integral absolute and relative tolerances

Returns:

scattering_rate – scattering rate double array (len(refpts), ) expressed in event/seconds
ma – momentum aperture (len(refpts), 2) array
refpts – refpts used for momentum aperture calculation (len(refpts), ) array