helium flow rate/sccm	CO selectivity/%	CO2 selectivity/%	C2H2 selectivity/%	CH4 selectivity/%	unassigned selectivity/%
250	32.50526295	33.45553401	11.48822958	2.157038329	20.39393513

500	24.69837207	30.76975364	10.43180376	1.734646267	32.36542426

750	21.4883375	33.44353927	10.64673861	1.593204483	32.82818014

1000	18.30949546	29.95358052	10.17979671	1.291326064	40.26580125

(b) The selectivity of the products at various He flow rates under an applied voltage of 650 V. 
    Conditions: 10 sccm O$_2$, 0.5 sccm C$_4$H$_{10}$, He varied at 250, 500, 750, and 1000 sccm. The products are arranged from left to right as CO (blue), CO$_2$ (green), CH$_4$ (red), and C$_2$H$_2$ (purple), unassigned species (gray). The unassigned species may originate from water or carbonaceous species on the dielectric and cannot be specifically identified. 