  We demonstrate the recent designs of Safe Extremum Seeking (Safe ES) on the 1
kilometer-long charged particle accelerator at the Los Alamos Neutron Science
Center (LANSCE). Safe ES is a modification of ES which, in addition to
minimizing an analytically unknown cost, also employs a safety filter based on
an analytically unknown control barrier function (CBF) safety metric.
Accelerator tuning is necessitated by the accelerators being large, with many
drifting parameters due to thermal effects and degradation. At the same time,
safe operation (the maintenance of state constraints) is crucial, as damage
brings astronomical costs, both financially and in operation downtime. Our
measured (but analytically unknown) safety metric is the beam current. We
perform multivariable Safe ES on three accelerator applications, in which we
adapt 4, 6, and 3 magnet strength parameters, respectively. Two of the three
applications are for validated simulation models of beamlines at LANSCE: the
first for the Proton Radiography (pRad) beamline of 800 MeV protons for spot
size tuning; the second on a high performance code, HPSim, for tuning the low
energy beam transport (LEBT) region of of 750 keV protons. The third is an
experimental tuning of the steering magnets in the LEBT at LANSCE.
