gap 36 is disposed between the electrode 32 and ground 38 during a flashback condition the presence of electrically charged particles e g ions enables a circuit path to be established between the electrode 32 and ground 38 and in response to the concentration of ions an electrical current is formed the strength of this current may be measured by a current sensor 40 it can be shown that the strength of this current is generally a function of at least the following exemplary factors or parameters the level of voltage applied by the voltage source 34 the proximity of the electrode to the source of the charged particles proximity to a flame front the surface area of the electrode the rate of formation of electrically charged species the convection of electrically charged species such as towards or away from the electrode and the rate of recombination of charged species to an electrically neutral state generally the last three factors are not with the control of the designer however the first three factors listed above singly or in combination may be suitably varied to accommodate the requirements of a given burner application fig4 is a schematic view of a conceptual field of detection 42 of ion sensing element 16 with respect to a flashback 44 and further with respect to the main combustion zone 14 it is noted that one exemplary advantage that results from an arrangement in accordance with aspects of the present invention is the ability to distinguish with a single electrode the flashback 44 from the flame in the main combustion zone 14 this arrangement is well.