Figure 1
From: First evaluation of a novel ionisation chamber for thermal neutron beam monitoring
Principle of operation of the 
. (a) 
filled with N2 gas. The neutron (grey) hits the atom of 14N and releases proton and Lithium (red solid lines). These travel in the gas, in turn releasing electrons and ions that are then attracted to cathode and anode, generating electric current. (b) The neutron (grey) hits the atom of 10B and releases α and Lithium (red solid line) back to back, so that only one of them is travelling in the air in the detector and in turn creating ions that generate electric current