+ NXmonoref ? {Suggested spectrum measurement for intensity vs. wavelength for a given slit setting. Warning: beam profile is not regular, but this effect is accommodated in the spectrum measurement} ? {Suggested background measurement. The referenced background measurement should indicate whether it is sample offset, detector offset or Qx offset.} { "specular"|"intensity"|"q_offset"|"sample_offset"|"detector_offset"|"slice"|"area"|"alignment"|"other" } { Reflectometry has a variety of standard scan types. Chief among these is the specular scan, which is the signal of interest. The intensity scan is required to normalize the signal and compute reflectivity. Background scans are made offsetting the sample or the detector, or offsetting both such that the background is measured at the same Qz (which measurement is used depends on the expected nature of the background). Slice scans are used to determine resolution or measure off-specular diffraction peaks. Area scans can measure a swathe of Q, yielding specular, background and slice measurements simultaneously. Various alignment scans are performed. Generally the user is not interested in these during reduction and analysis. Other scans are done for unusual measurements not related to reflectivity. } * {scan range for the named field; for display and sorting purposes; the field name(s) can be instrument and measurement specific.} ? {Sample angle relative to beam from the monochromator} "vertical|horizontal" ? { Location of slit along beamline (midway between slits if slits are not coplanar). This is required to compute instrument resolution. } "nxvertical_slit|nxhorizontal_slit" { Aperature opening. Use the instrument_geometry field to determine if the slit defines resolution in Qz. Square aperatures should be represented by two vertical and horizontal slits at the same location. Warning: vertical slits refers to the orientation of the slit blades. They open horizontally. } {Use 90 for spin up, -90 for spin down for neutrons perpendicular to the beam.} {Use 0 for neutrons perpendicular to the beam and 90 for neutrons parallel to the beam, or -90 for neutrons antiparallel.} ? { Need all fields so that we can calculate shadow of beam stop on detector, and not use those pixels when calculating background. }? { Angle of the detector relative to the scattering center. } { Indicate sense of scattering: 0 = front of sample, 180 = back of sample. If the beam is entering the side of the sample and reflecting off the back surface of the film then the polar angle will be negative, with negative angles interpreted as inverting the scattering length density profile of the film. Note that the absorption is likely to be high in these circumstances, though measuring the intensity scan through the sample will normalize for this automatically. Users beware that the NeXus file writer may not know whether the instrument geometry is measuring reflection off the back of the sample (azimuthal_angle=180, polar_angle>0) or reflection off the back surface of the front of the sample (azimuthal_angle=0, polar_angle < 0), so software needs to allow the polar_angle to be negated. } ? {"monitor"|"timer"} {preset value for time in seconds or monitor in counts} {Monitor counts, absent if no monitor}? {Elapsed time for each scan point} {Start time for each scan point relative to start of the measurement} * { Various logs for temperature, field, etc. which are assumed to be constant over the duration of the run. The reduction program should be able to display their values on a parallel graph. Note that logs are not necessarily sampled synchronously with the data points; use NXtimer and plot data points vs. start_time }