In this page, we are looking to harvest information about calibrations that are performed at neutron reflectometry instruments. For a given calibration, please include the following information:
- What is being calibrated?
- How is the calibration performed?
- An example of the calibrated data and details of how you get this information
- References/Code for the above would be great!
Once you add your calibration, please include yourself in the authors of this page.
Things to get you thinking: (if you calibrate/measure something not on this list then please let us know)
- How do you measure the total flux of your beamline?
- How do you measure the TOF flight distance of your beamline with neutrons (and without?) Neutron TOF only
- How do you measure the wavelength or wavelengths of your beamline? Similar to 2 but for monochromatic beamlines.
- How do you measure the polarisation of your beamline? (TOF, monochromatic)
- How do you check with a non-magnetic sample you get zero magnetic response with polarised neutrons, i.e your zero is zero, and to what precision? (TOF/Mono)
- If you have a pixelated detector. How do you measure your detector corrections to then flatten the detector response? (i.e. Correct all pixels to have a similar response, this is sometimes referred to as a flood measurement)
- If you have a pixelated detector how do you measure the pixel positions (often called a detector map)
- How do your scan your slit gaps and positions (bit brain dead this one but everyone has to do it)
- How do you measure the feathering function for the moderator (I know this is a TOF source thing at pulses sources)
- How do you measure the resolution function for your beamline.
- How do you measure the background levels for your beamline. Lots of things here (dark/quiet counts for detector noise, instrument background from cosmic noise, incoherent background during a reflectivity measurement from samples etc.)
- How do you calibrate your angle stages to ensure that when you move a degree they move a degree.
- How do you label your polarisation states?
- How do you measure the lateral coherence length of the beamline. (important for offspecular scattering, or if you have partial surface coverage; 10.1103/PhysRevA.89.033851)
- How do you measure guide structure. Using pinhole camera setup. Plus a special neutron camera. See Platypus paper
Frequent Calibration Examples
- DCD q-calibration at I07 Diamond
- Flood detector POLREF-ISIS
Infrequent Calibration Examples
- Time-of-flight distance