4 .. figure:: ../../../figures/4S+2D.png
8 Schematic view of the diffractometer.
13 + xrays source fix allong the :math:`\vec{x}` direction (1, 0, 0)
14 + 4 axes for the sample
16 + **mu** : rotating around the :math:`\vec{z}` direction (0, 0, 1)
17 + **omega** : rotating around the :math:`-\vec{y}` direction (0, -1, 0)
18 + **chi** : rotating around the :math:`\vec{x}` direction (1, 0, 0)
19 + **phi** : rotating around the :math:`-\vec{y}` direction (0, -1, 0)
21 + 2 axes for the detector
23 + **gamma** : rotation around the :math:`\vec{z}` direction (0, 0, 1)
24 + **delta** : rotation around the :math:`-\vec{y}` direction (0, -1, 0)
32 PseudoAxes provided : **h**, **k** and **l**
34 + mode **bissector_vertical**
36 + Axes: **omega**, **chi**, **phi**, **delta**
37 + Parameters : No parameter
39 This mode add the bissector constrain ``delta = 2 * omega``. In this
40 mode the **chi** circle containt the vector of diffusion
41 :math:`\vec{Q}`. So it is easy to know the orientation of the hkl
44 + mode **constant_omega_vertical**
46 + Axes: **"chi"**, **"phi"**, **"delta"**
47 + Parameters : no parameter
49 This mode do not move the **omega** axis.
51 + mode **constant_chi_vertical**
53 + Axes: **"omega"**, **"phi"**, **"delta"**
54 + Parameters : no parameter
56 This mode do not move the **chi** axis.
58 + mode **constant_phi_vertical**
60 + Axes : **"omega"**, **"chi"**, **"delta"**
61 + Parameters : no parameter
63 This mode do not move the **phi** axis.
65 + mode : **lifting_detector_phi**
67 + Axes : **"phi"**, **"gamma"**, **"delta"**
68 + Parameters : No Parameters
70 + mode : **lifting_detector_omega**
72 + Axes : **"omega"**, **"gamma"**, **"delta"**
73 + Parameters : No Parameters
75 + mode : **lifting_detector_mu**
77 + Axes : **"mu"**, **"gamma"**, **"delta"**
78 + Parameters : No Parameters
80 + mode : **double_diffraction vertical**
82 + Axes : **"omega"**, **"chi"**, **"phi"**, **"delta"**
83 + Parameters : **h2**, **k2**, **l2**
85 This mode put a second hkl vector (**h2**, **k2**, **l2**) in Bragg
86 condition. This is usefull sometimes when you want to explore two
87 bragg peaks without moving your sample.
89 + mode : **bissector_horizontal**
91 + Axes : **"mu"**, **"omega"**, **"chi"**, **"phi"**, **"gamma"**
92 + Parameters : No parameters
94 + mode : **double_diffraction_horizontal**
96 + Axes : **"mu"**, **"omega"**, **"chi"**, **phi**, **"gamma"**
97 + Parameters : **h2**, **k2**, **l2**
99 This mode put a second hkl vector (**h2**, **k2**, **l2**) in Bragg
100 condition. This is usefull sometimes when you want to explore two
101 bragg peaks without moving your sample.
103 + mode : **psi_constant_vertical**
105 + Axes : **"omega"**, **"chi"**, **phi**, **"delta"**
106 + Parameters : **h2**, **k2**, **l2**, **psi**
108 This mode allow to fix the value of the pseudo axis **psi** at a
109 constant value when you move around an **h**, **k** , **l**
110 position. The (**h2**, **k2**, **l2**) vector is used as a reference
111 for the computation of the **psi** pseudo axis value.
113 You can retrive and ``freeze`` the current value of the **psi**
114 pseudo axis value into the **psi** parameter when you initialize the
115 mode. But you can also write directly the value of the desired
121 PseudoAxis provided : **psi**
123 + mode **psi_vertical**
125 + Axes : **komega**, **kappa**, **kphi**, **delta**
126 + Parameters : **h1**, **k1**, **l1**
128 The (**h1**, **k1**, **l1**) vector is used as a reference for the
129 computation of the **psi** pseudo axis value.
134 PseudoAxis provided : **q**, **alpha**
136 where **q** is :math:`|\vec{Q}| = \frac{2 \tau}{\lambda} \sin{\theta}`
137 and **alpha** is the azimuth of :math:`\vec{Q}` in the ``yz``
138 plan. The origin of this angles is the :math:`\vec{y}` vector, and the
139 positive rotation along :math:`\vec{x}`
143 + Axes : **"gamma"**, **"delta"**
144 + Parameters : no parameter