Collection of python scripts used to reduce and analyze USANS data

Description

Data reduction and correction are the processes by which raw output from a small angle scattering instrument is converted to absolute units (1/cm), enabling direct comparison to corrected data from other instruments. Specifically, the raw scattering angle is converted to wavevector Q, raw detector counts are scaled according to the incident intensity of the beam, any defects in the detector are accounted for, and normalized counts are converted to units of 1/cm. To reduce data from the ultra-small angle neutron scattering instrument at the NIST Center for Neutron Research (NCNR), including correction with a model Q-dependent background function, we wrote a series of python scripts. We follow the protocol outlined in the help file of the NCNR USANS Reduction Macros for Igor, but our scripts are amenable to reducing many measurements at once. More information can be found in Appendix A of Rachel Ford's PhD thesis. We also include the script used to search for a fit to the Q-dependent background (QDB). This step is optional, depending on your needs, and if used, should be applied between steps 2 & 3 in the reduction procedure. A program to computationally slit-smear SANS data, described by a linear combination of power laws, is also included. Smearing SANS data enables one to directly compare SANS and USANS data for a single sample, which spans five decades in Q.

Files

Additional details