  This is the documentation of Computed Tomography (CT) data of a pen-spring.
The open data set is available at
https://zenodo.org/record/3266936#.XRyMdCZS9oA and can be freely used for
scientific purposes with appropriate references to the data and to this
document in arxiv.org. The provided data set includes the X-ray sinograms ({\tt
finalSino}) of a single 2D slice from a different height of the spring. The
{\tt finalSino} was obtained from a measured 10-projection or 100-projection
{\tt sinogram} using fan-beam geometry by down-sampling and taking logarithms.
The data set includes also those original measured {\tt sinogram}s and
corresponding measurement matrices.
