The invention provides human nucleic acid-associated proteins and polynucleotides which identify and encode NAAP. The spray nozzle includes a wall-surface dedicated nozzle provided along a wall surface in the CO2 absorber and a liquid dispersion nozzle provided inside of the wall-surface dedicated nozzle in the CO2 absorber. The system comprises an electron detector configured for detecting the secondary electrons, and a deflecting field configured to deflect a trajectory of the secondary electrons, which were propagating towards the FIB column, to propel away from the beam axis and towards the electron detector.