Unit Factory

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What is it?

The Unit Factory is a Dynamic Factory that creates and hands out instances of Mantid Unit objects.

Available units

The following units are available in the default Mantid distribution.

Name ID (as known by Unit Factory) Unit Relevant equation
Time of flight TOF μs TOF
Wavelength Wavelength \mathrm{\AA} \lambda = \frac{h}{p} = \frac{h \times \mathrm{tof}}{m_N \times L_{tot}}
Energy Energy meV E = \frac{1}{2} mv^2 = \frac{m_N}{2} \left ( \frac{L_{tot}}{\mathrm{tof}} \right )^2
d-spacing dSpacing \mathrm{\AA} d = \frac{n \, \lambda}{2 \, sin \, \theta}
Momentum transfer (Q) MomentumTransfer \mathrm{\AA}^{-1} Q = 2 \, k \, sin \, \theta = \frac{4 \pi sin \theta}{\lambda}
Momentum transfer squared (Q2) QSquared \mathrm{\AA}^{-2} Q^2 \frac{}{}
Energy transfer DeltaE meV \Delta E = E_{i}-\frac{1}{2}m_N \left ( \frac{L_2}{\mathrm{tof}-L_1\sqrt{\frac{m_N}{2E_i}}} \right )^2
Energy transfer in wavenumber DeltaE_inWavenumber cm − 1 8.06554465ΔE

Where L1 and L2 are sample to the source and sample to detector distances respectively, Ltot = L1 + L2 and Ei is the energy of neutrons leaving the source.

Adding new units

Writing and adding a new unit is relatively straightforward. Instructions will appear here in due course. In the meantime if a unit that you require is missing, then please contact the development team and we will add it to the default Mantid library.

Retrieved from "http://www.mantidproject.org/Unit_Factory"
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