TRANSVERSE PHASE-SPACE BEAM TOMOGRAPHY AT PSI AND SNS PROTON ACCELERATORS

Operation and upgrade of very intense proton beam accelerators like the PSI facility and the neutron spallation source (SNS) at ORNL is typically constrained by potentially large machine activation. Besides the standard beam diagnostics, beam tomography techniques provide a reconstruction of the beam transverse phase space distribution, giving insights to potential loss sources like irregular tails or halos. Unlike more conventional measurement approaches (pepper pot, slits) beam tomography is a non destructive method that can be performed at high energies and, virtually, at any beam location. Results from the application of the Maximum Entropy Tomography (MENT) algorithm [1] to different beam sections at PSI and SNS are shown. In these reconstructions the effect of non-linear forces is made visible in a way not otherwise available through wire scanners alone. These measurements represent a first step towards the design of a beam tomography implementation that can be smoothly employed as a reliable diagnostic tool.