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## 32. SESANS calculation routines

## `sasmodels.sesans`

Conversion of scattering cross section from SANS (I(q), or rather, ds/dO) in absolute units (cm-1)into SESANS correlation function G using a Hankel transformation, then converting the SESANS correlation function into polarisation from the SESANS experiment

Everything is in units of metres except specified otherwise (NOT TRUE!!!) Everything is in conventional units (nm for spin echo length)

Wim Bouwman (w.g.bouwman@tudelft.nl), June 2013

class sasmodels.sesans.SesansTransform(z: ndarray, SElength: float, lam: float, zaccept: float, Rmax: float, log_spacing: float = 1.0003)

  Bases: `object`

  Spin-Echo SANS transform calculator. Similar to a resolution function, the SesansTransform object takes I(q) for the set of q_calc values and produces a transformed dataset

  SElength (A) is the set of spin-echo lengths in the measured data.

  zaccept (1/A) is the maximum acceptance of scattering vector in the spin echo encoding dimension (for ToF: Q of min(R) and max(lam)).

  Rmax (A) is the maximum size sensitivity; larger radius requires more computation time.

  apply(Iq: ndarray) → ndarray

    Apply the SESANS transform to the computed I(q).

  q: ndarray = None

    SElength from the data in the original data units; not used by transform but the GUI uses it, so make sure that it is present.

  q_calc: ndarray = None

    q values to calculate when computing transform