An analytical apparatus comprising: a low energy electron impact ioniser including: an electron emitter; an ionisation target zone, arranged to be populated with analyte matter to be ionised; and an electron extracting element aligned with an electron pathway defined between the electron emitter and the ionisation target zone; a voltage supply operative to generate a positive potential difference between the emitter and the ionisation target zone between 5 and 30 V to generate an electron ionisation energy at the ionisation target zone of between 5 and 30 eV; a voltage supply for creating a positive potential difference between the emitter and the electron extracting element; an electron focussing element; and an analyser comprising a detector for detecting ions wherein the positive potential difference between the emitter and the electron extracting element is greater than the positive potential difference between the emitter and the ionisation target zone such that the electron extracting element is configured to accelerate electrons away from the emitter along the electron pathway between the emitter and the extracting element and to decelerate the electrons along the electron pathway between the extracting element and the ionisation target zone; the electron focussing element is located between the emitter and the electron extracting element to focus the electrons along the electron pathway to the electron extracting element. a low energy electron impact ioniser including: an electron emitter; an ionisation target zone, arranged to be populated with analyte matter to be ionised; and an electron extracting element aligned with an electron pathway defined between the electron emitter and the ionisation target zone; a voltage supply operative to generate a positive potential difference between the emitter and the ionisation target zone between 5 and 30 V to generate an electron ionisation energy at the ionisation target zone of between 5 and 30 eV; a voltage supply for creating a positive potential difference between the emitter and the electron extracting element; an electron focussing element; and an analyser comprising a detector for detecting ions an electron emitter; an ionisation target zone, arranged to be populated with analyte matter to be ionised; and an electron extracting element aligned with an electron pathway defined between the electron emitter and the ionisation target zone; a voltage supply operative to generate a positive potential difference between the emitter and the ionisation target zone between 5 and 30 V to generate an electron ionisation energy at the ionisation target zone of between 5 and 30 eV; a voltage supply for creating a positive potential difference between the emitter and the electron extracting element; an electron focussing element; and an analyser comprising a detector for detecting ions wherein the positive potential difference between the emitter and the electron extracting element is greater than the positive potential difference between the emitter and the ionisation target zone such that the electron extracting element is configured to accelerate electrons away from the emitter along the electron pathway between the emitter and the extracting element and to decelerate the electrons along the electron pathway between the extracting element and the ionisation target zone; the electron focussing element is located between the emitter and the electron extracting element to focus the electrons along the electron pathway to the electron extracting element.