  The proton radiography diagnostic is widely used in laser-plasma experiments
to make magnetic field measurements. Recent developments in analysis have
enabled quantitative reconstruction of path-integrated magnetic field values,
but making conclusions about the three-dimensional structure of the fields
remains challenging. In this Letter we propose and demonstrate in kinetic
simulations a novel target geometry which makes possible the production of
multiple proton beams from a single laser pulse, enabling the application of
tomographic methods to proton radiography.
