neutronpy.instrument.GetTau¶

neutronpy.instrument.GetTau(x, getlabel=False)[source]¶

τ-values for common monochromator and analyzer crystals.

Parameters:

x : float or string

Either the numerical Tau value, in Å^-1, or a common monochromater / analyzer type. Currently included crystals and their corresponding τ values are

String τ

Be(002) 3.50702

Co0.92Fe0.08(200) 3.54782 (Heusler)

Cu(002) 3.47714

Cu(111) 2.99913

Cu(220) 4.91642

Cu2MnAl(111) 1.82810 (Heusler)

Ge(111) 1.92366

Ge(220) 3.14131

Ge(311) 3.68351

Ge(511) 5.76968

Ge(533) 7.28063

PG(002) 1.87325

PG(004) 3.74650

PG(110) 5.49806

Si(111) 2.00421

getlabel : boolean

If True, return the name of the common crystal type that is a match to the input τ.

Returns:

tau : float or string: Returns either the numerical τ for a given crystal type or the name of a crystal type

Notes

Tau is defined as \(\tau = 2\pi/d\), where d is the d-spacing of the crystal in Angstroms.

Translated from ResLib 3.4c, originally authored by A. Zheludev, 1999-2007, Oak Ridge National Laboratory