  We analyze the collisional Penrose process between a particle on the ISCO
orbit around an extreme Kerr black hole and a particle impinging from infinity.
We consider both cases with non-spinning and spinning particles. We evaluate
the maximal efficiency, $\eta_{\text{max}}=(\text{extracted
energy})/(\text{input energy})$, for the elastic collision of two massive
particles and for the photoemission process, in which the ISCO particle will
escape to infinity after the collision with a massless impinging particle. For
non-spinning particles, the maximum efficiency is $\eta_{\text{max}} \approx
2.562$ for the elastic collision and $\eta_{\text{max}} \approx 7$ for the
photoemission process. While for spinning particles we obtain the maximal
efficiency $\eta_{\text{max}} \approx 8.442$ for the elastic collision and
$\eta_{\text{max}} \approx 12.54$ for the photoemission process.
