.. auto-generated by script ../../../../utils/nxdl2rst.py from the NXDL source NXguide.nxdl.xml .. index:: ! NXguide (base class) ! guide (base class) see: guide (base class); NXguide .. _NXguide: ======= NXguide ======= **Status**: base class, extends :ref:`NXobject` **Description**: A neutron optical element to direct the path of the beam. :ref:`NXguide` is used by neutron instruments to describe a guide consists of several mirrors building a shape through which neutrons can be guided or directed. The simplest such form is box shaped although elliptical guides are gaining in popularity. The individual parts of a guide usually have common characteristics but there are cases where they are different. For example, a neutron guide might consist of 2 or 4 coated walls or a supermirror bender with multiple, coated vanes. To describe polarizing supermirrors such as used in neutron reflection, it may be necessary to revise this definition of :ref:`NXguide` to include :ref:`NXpolarizer` and/or :ref:`NXmirror`. When even greater complexity exists in the definition of what constitutes a *guide*, it has been suggested that :ref:`NXguide` be redefined as a :ref:`NXcollection` of :ref:`NXmirror` each having their own :ref:`NXgeometry` describing their location(s). For the more general case when describing mirrors, consider using :ref:`NXmirror`. NOTE: The NeXus International Advisory Committee welcomes comments for revision and improvement of this definition of :ref:`NXguide`. **Symbols**: **nsurf**: number of reflecting surfaces **nwl**: number of wavelengths **Groups cited**: :ref:`NXdata`, :ref:`NXgeometry` .. index:: NXgeometry (base class); used in base class, NXdata (base class); used in base class **Structure**: .. _/NXguide@default-attribute: .. index:: default (file attribute) **@default**: (optional) :ref:`NX_CHAR ` .. index:: plotting Declares which child group contains a path leading to a :ref:`NXdata` group. It is recommended (as of NIAC2014) to use this attribute to help define the path to the default dataset to be plotted. See https://www.nexusformat.org/2014_How_to_find_default_data.html for a summary of the discussion. .. _/NXguide/description-field: .. index:: description (field) **description**: (optional) :ref:`NX_CHAR ` A description of this particular instance of ``NXguide``. .. _/NXguide/incident_angle-field: .. index:: incident_angle (field) **incident_angle**: (optional) :ref:`NX_FLOAT ` {units=\ :ref:`NX_ANGLE `} TODO: documentation needed .. _/NXguide/bend_angle_x-field: .. index:: bend_angle_x (field) **bend_angle_x**: (optional) :ref:`NX_FLOAT ` {units=\ :ref:`NX_ANGLE `} TODO: documentation needed .. _/NXguide/bend_angle_y-field: .. index:: bend_angle_y (field) **bend_angle_y**: (optional) :ref:`NX_FLOAT ` {units=\ :ref:`NX_ANGLE `} TODO: documentation needed .. _/NXguide/interior_atmosphere-field: .. index:: interior_atmosphere (field) **interior_atmosphere**: (optional) :ref:`NX_CHAR ` Any of these values: ``vacuum`` | ``helium`` | ``argon`` .. _/NXguide/external_material-field: .. index:: external_material (field) **external_material**: (optional) :ref:`NX_CHAR ` external material outside substrate .. _/NXguide/m_value-field: .. index:: m_value (field) **m_value[nsurf]**: (optional) :ref:`NX_FLOAT ` The ``m`` value for a supermirror, which defines the supermirror regime in multiples of the critical angle of Nickel. .. _/NXguide/substrate_material-field: .. index:: substrate_material (field) **substrate_material[nsurf]**: (optional) :ref:`NX_FLOAT ` TODO: documentation needed .. _/NXguide/substrate_thickness-field: .. index:: substrate_thickness (field) **substrate_thickness[nsurf]**: (optional) :ref:`NX_FLOAT ` {units=\ :ref:`NX_LENGTH `} TODO: documentation needed .. _/NXguide/coating_material-field: .. index:: coating_material (field) **coating_material[nsurf]**: (optional) :ref:`NX_FLOAT ` TODO: documentation needed .. _/NXguide/substrate_roughness-field: .. index:: substrate_roughness (field) **substrate_roughness[nsurf]**: (optional) :ref:`NX_FLOAT ` {units=\ :ref:`NX_LENGTH `} TODO: documentation needed .. _/NXguide/coating_roughness-field: .. index:: coating_roughness (field) **coating_roughness[nsurf]**: (optional) :ref:`NX_FLOAT ` {units=\ :ref:`NX_LENGTH `} TODO: documentation needed .. _/NXguide/number_sections-field: .. index:: number_sections (field) **number_sections**: (optional) :ref:`NX_INT ` {units=\ :ref:`NX_UNITLESS `} number of substrate sections (also called ``nsurf`` as an index in the ``NXguide`` specification) .. _/NXguide/GEOMETRY-group: **GEOMETRY**: (optional) :ref:`NXgeometry` TODO: Explain what this NXgeometry group means. What is intended here? .. _/NXguide/reflectivity-group: **reflectivity**: (optional) :ref:`NXdata` Reflectivity as function of reflecting surface and wavelength .. _/NXguide/reflectivity@signal-attribute: .. index:: signal (group attribute) **@signal**: (optional) :ref:`NX_CHAR ` Obligatory value: ``data`` .. _/NXguide/reflectivity@axes-attribute: .. index:: axes (group attribute) **@axes**: (optional) :ref:`NX_CHAR ` Obligatory value: ``surface wavelength`` .. _/NXguide/reflectivity@surface_indices-attribute: .. index:: surface_indices (group attribute) **@surface_indices**: (optional) :ref:`NX_CHAR ` Obligatory value: ``0`` .. _/NXguide/reflectivity@wavelength_indices-attribute: .. index:: wavelength_indices (group attribute) **@wavelength_indices**: (optional) :ref:`NX_CHAR ` Obligatory value: ``1`` .. _/NXguide/reflectivity/data-field: .. index:: data (field) **data[nsurf, nwl]**: (optional) :ref:`NX_NUMBER ` reflectivity of each surface as a function of wavelength .. _/NXguide/reflectivity/surface-field: .. index:: surface (field) **surface[nsurf]**: (optional) :ref:`NX_NUMBER ` {units=\ :ref:`NX_ANY `} List of surfaces. Probably best to use index numbers but the specification is very loose. .. _/NXguide/reflectivity/wavelength-field: .. index:: wavelength (field) **wavelength[nwl]**: (optional) :ref:`NX_NUMBER ` {units=\ :ref:`NX_WAVELENGTH `} wavelengths at which reflectivity was measured Hypertext Anchors ----------------- Table of hypertext anchors for all groups, fields, attributes, and links defined in this class. ============================================================================================================== ============================================================================================================== documentation (reST source) anchor web page (HTML) anchor ============================================================================================================== ============================================================================================================== :ref:`/NXguide/bend_angle_x-field ` :ref:`#nxguide-bend-angle-x-field ` :ref:`/NXguide/bend_angle_y-field ` :ref:`#nxguide-bend-angle-y-field ` :ref:`/NXguide/coating_material-field ` :ref:`#nxguide-coating-material-field ` :ref:`/NXguide/coating_roughness-field ` :ref:`#nxguide-coating-roughness-field ` :ref:`/NXguide/description-field ` :ref:`#nxguide-description-field ` :ref:`/NXguide/external_material-field ` :ref:`#nxguide-external-material-field ` :ref:`/NXguide/GEOMETRY-group ` :ref:`#nxguide-geometry-group ` :ref:`/NXguide/incident_angle-field ` :ref:`#nxguide-incident-angle-field ` :ref:`/NXguide/interior_atmosphere-field ` :ref:`#nxguide-interior-atmosphere-field ` :ref:`/NXguide/m_value-field ` :ref:`#nxguide-m-value-field ` :ref:`/NXguide/number_sections-field ` :ref:`#nxguide-number-sections-field ` :ref:`/NXguide/reflectivity-group ` :ref:`#nxguide-reflectivity-group ` :ref:`/NXguide/reflectivity/data-field ` :ref:`#nxguide-reflectivity-data-field ` :ref:`/NXguide/reflectivity/surface-field ` :ref:`#nxguide-reflectivity-surface-field ` :ref:`/NXguide/reflectivity/wavelength-field ` :ref:`#nxguide-reflectivity-wavelength-field ` :ref:`/NXguide/reflectivity@axes-attribute ` :ref:`#nxguide-reflectivity-axes-attribute ` :ref:`/NXguide/reflectivity@signal-attribute ` :ref:`#nxguide-reflectivity-signal-attribute ` :ref:`/NXguide/reflectivity@surface_indices-attribute ` :ref:`#nxguide-reflectivity-surface-indices-attribute ` :ref:`/NXguide/reflectivity@wavelength_indices-attribute ` :ref:`#nxguide-reflectivity-wavelength-indices-attribute ` :ref:`/NXguide/substrate_material-field ` :ref:`#nxguide-substrate-material-field ` :ref:`/NXguide/substrate_roughness-field ` :ref:`#nxguide-substrate-roughness-field ` :ref:`/NXguide/substrate_thickness-field ` :ref:`#nxguide-substrate-thickness-field ` :ref:`/NXguide@default-attribute ` :ref:`#nxguide-default-attribute ` ============================================================================================================== ============================================================================================================== **NXDL Source**: https://github.com/FAIRmat-Experimental/nexus_definitions/tree/fairmat/base_classes/NXguide.nxdl.xml