A critical analysis of the technique of spin tune mapping in storage rings

A paper has recently been published which describes the technique of so-called 'spin tune mapping' to measure the 'stable spin axis' (spin closed orbit) of a spin polarized beam circulating in a storage ring. This paper presents an independent analysis of the technique, and significantly different findings are reported below. In particular, it is derived that there are several unquantified systematic errors which are not treated in the previous analysis.