ISIS injector linac emittance measurement and phase-space tomography

Accurate beam emittance measurement and characterizing beam parameters are essential steps in the performance improvement and better physics studies of high-intensity proton beam accelerators. While various procedures exist for measuring beam parameters, they often come with limitations and provide only a linear space charge approximation of the phase space ellipse. To achieve better characterization, it is crucial to obtain a comprehensive view of the phase space distribution and investigate nonlinearities. The ISIS neutron spallation source, one of the world's oldest machines, boasts a 70 MeV injector linac and 800 MeV RCS with plans for operation for the next twenty years. Future upgrades aim to increase beam intensity to 300 microamps while minimizing beam loss. Machine physics cycles are actively pursued to achieve these targets. Beam parameters at the output of the injector profoundly impact maximum transmission and high-quality beam matching to the Rapid Cycling Synchrotron of the ISIS machine. This paper presents the results of phase space tomographic reconstruction and quadrupole scan results for emittance measurement at the end of the ISIS 70 MeV injector. The findings demonstrate a strong correlation between tomographic measurement and simulation results, indicating the efficacy of the proposed method in accurately characterizing beam properties.