This experiment will be a continuation of MA5167 of July 2022 and a preparation for A32-2-863 by Martin Sanchez et al. to be performed in May. The experiment is scheduled on top of proposal A32-2-857 : Improving the accuracy of the "Rainbow" rotating-diamond-filter method, Major progress with the Rainbow method was already obtained following inhouse experiment BLC14429 in March 2023. A new diamond rotation stage was bought, with better motor absolute accuracy . The samples by Martin Sanchez et al will be used as "demonstration samples" for the now-more-accurate method.