CalMuonDetectorPhases-v1.rst



Description
Calculates detector asymmetries and phases from a reference dataset. The algorithm fits each of
the spectra in the input workspace to:
f_i(t) = A_i \sin\left(\omega t + \phi_i\right)

where \omega is shared across spectra and A_i and \phi_i are
detector-dependent.
Before the spectra are fitted, \omega is determined by grouping the detectors,
calculating the asymmetry and fitting this to get the frequency. This value of \omega
is then treated as a fixed constant when fitting the spectra to the function above.
The algorithm outputs a table workspace containing the spectrum number, the asymmetry and the phase.
This table is intended to be used as the input
PhaseTable to :ref:`PhaseQuad <algm-PhaseQuad>`.
Usually for muon instruments, each spectrum will correspond to one detector (spectrum number = detector ID).
In addition, the fitting results are returned
in a workspace group, where each of the items stores the original data (after removing the
exponential decay), the data simulated with the fitting function and the difference between data
and fit as spectra 0, 1 and 2 respectively.
There are five optional input properties: FirstGoodData and LastGoodData define the fitting range.
When left blank, FirstGoodData is set to the value stored in the input workspace and LastGoodData
is set to the last available bin. The optional property Frequency allows the user to select an
initial value for \omega (a starting value for the fit). If this property is not supplied, the
algorithm takes this value from the sample_magn_field log multiplied by 2\pi\cdot g_\mu, where
g_\mu is the muon gyromagnetic ratio (0.01355 MHz/G).
Finally, the optional properties ForwardSpectra and BackwardSpectra are the sets of spectra in the
forward and backward groups. If these are not supplied, the algorithm will find the instrument from the
input workspace and use the default grouping for this instrument.

Usage
Example - CalMuonDetectorPhases
Output: