  Towards radiation tolerant sensors for pico-second timing, several dopants
are explored. Using a common mask, CNM produced LGADs with boron, boron +
carbon and gallium implanted gain layers are studied under neutron and proton
irradiation. With fluences ranging from $10^{14}$ to $6\times 10^{15}
n_{eq}/cm^{2}$ on both particle species, reported results focus on acceptor
removal and gain reduction via electrical characterization. Timing performance,
charge collection, gain and relative efficiency are treated through charged
particle measurements, including signal analysis and noise characterization. An
accent is placed on stability, via dark rate and operating voltage studies
while, radiation related gain reduction mechanisms are examined comparing gain
estimations through different approaches.
