A neutron conversion foil for being used in a neutron detector includes a substrate having a first and second side. The substrate is covered at least on one of the first and second sides with a neutron conversion layer made of a neutron reactive material and being capable of capturing neutrons to thereafter emit light and/or charged particles. The neutron conversion foil is transparent to light such that light originating from the conversion of neutrons can pass through one or several of the neutron conversion foils and thereafter be collected and detected by a light sensing device.
