maskUtils#
Many sample environments used routinely on SNAP affect the scattered beam in a way that affects specific pixels. These effects are managed by masking the data during the SNAPRed reduction workflow and maskUtils contains the functions to support this. Generally, there are two types of masks used:
“pixel” masks, which remove all events in specified pixels from the reduction process and
“bin” masks, which remove events from specific bins within specified pixels. (This is often referred to as a “Swiss Cheese” mask as it literally creates holes in the volumetric TOF data)
These masks are handled separately by the underlying mantid code and this necessitates distinct approaches within snapwrap. An important detail is that, generally, a list of masks will be specified when reducing data, and these masks will be combined to exclude all corresponding events.