Design and engineering of ionization gas sensor based on Mn nano-flower sculptured thin film as cathode and a stainless steel ball as anode

•Chiral sculptured Mn nano-flower thin films produced and used as cathode in the gas sensor.•A new shape for the anode electrode (stainless steel ball) is proposed and used in the gas sensor.•At high gas pressures the breakdown voltage decreased with the anode sizes, while at low pressures the opposite behavior was observed.•For pd values between 0.025 and 0.2 mbar cm and for different gases a good gas selectivity was obtained.