A neutron porosity measurement device, comprising: a cavity configured to receive a neutron source that emits neutrons; a first semiconductor detector (100, 101, 150, 220) located at a first distance from the cavity; and a second semiconductor detector (100, 101, 150, 230) located at a second distance larger than the first distance from the cavity, wherein each of the first and the second semiconductor detector (220, 230) includes a semiconductor substrate, the semi-conductor substrate being doped to form a pn junction, and electrodes (160, 170), one of which is in contact with a first surface of the semiconductor substrate and another one of which is in contact with a second surface of the semiconductor substrate, the second surface being opposite to the first surface, the electrodes being configured to acquire an electrical signal occurring when a neutron is captured inside the semiconductor substrate, characterized in that the semi-conductor substrate has microstructures of neutron reactive material formed to extend from a first surface inside the semiconductor substrate, the pn junction causes an electric field within the semi-conductor substrate sufficient to cause collection of free charged particles generated in the neutron reactive material at the electrodes (160, 170); and wherein the neutron porosity measurement device does not include a high power source coupled to the first semiconductor detector and/or the second semi-conductor detector to provide an electric field within the semi-conductor substrate. a cavity configured to receive a neutron source that emits neutrons; a first semiconductor detector (100, 101, 150, 220) located at a first distance from the cavity; and a second semiconductor detector (100, 101, 150, 230) located at a second distance larger than the first distance from the cavity, wherein each of the first and the second semiconductor detector (220, 230) includes a semiconductor substrate, the semi-conductor substrate being doped to form a pn junction, and electrodes (160, 170), one of which is in contact with a first surface of the semiconductor substrate and another one of which is in contact with a second surface of the semiconductor substrate, the second surface being opposite to the first surface, the electrodes being configured to acquire an electrical signal occurring when a neutron is captured inside the semiconductor substrate, characterized in that the semi-conductor substrate has microstructures of neutron reactive material formed to extend from a first surface inside the semiconductor substrate, the pn junction causes an electric field within the semi-conductor substrate sufficient to cause collection of free charged particles generated in the neutron reactive material at the electrodes (160, 170); and wherein the neutron porosity measurement device does not include a high power source coupled to the first semiconductor detector and/or the second semi-conductor detector to provide an electric field within the semi-conductor substrate. the semi-conductor substrate has microstructures of neutron reactive material formed to extend from a first surface inside the semiconductor substrate, the pn junction causes an electric field within the semi-conductor substrate sufficient to cause collection of free charged particles generated in the neutron reactive material at the electrodes (160, 170); and wherein the neutron porosity measurement device does not include a high power source coupled to the first semiconductor detector and/or the second semi-conductor detector to provide an electric field within the semi-conductor substrate.