An elementary particle detector, this detector comprising: - a cathode and a conducting grid able to create a potential difference able to accelerate electrons in the direction of the conducting grid, the conducting grid being able to be traversed by the accelerated electrons, - a dynode interposed between the cathode and the conducting grid, this dynode being able, for each elementary particle, to produce an avalanche of secondary electrons, this dynode comprising for this purpose several channels, each channel comprising an emissive material, this emissive material being capable, in response to an impact of an electron, of generating, on average, more than one secondary electron, - a reader plate (16; 200) arranged on the side of the conducting grid opposite to the dynode, this reader plate comprising: • an external face arranged in such a manner as to be impacted by the avalanche of secondary electrons, and • electrodes (120; 252) arranged next to one another in a face parallel to or coincident with the external face, - first sensors able to measure the quantity of electrical charges on the electrodes, - a processing unit capable of determining the location of the avalanche of electrons based on the quantity of electrical charges measured by the first sensors and on the known location of the electrodes, characterized in that : - the detector comprises at least a second sensor , each second sensor being able to measure an electrical signal produced by the secondary electrons when they pass through the conducting grid, and - the processing unit is capable, in addition, of establishing a time of arrival of the elementary particle based on a time referred to as "crossing time" where the electrical signal is measured by the second sensor. - a cathode and a conducting grid able to create a potential difference able to accelerate electrons in the direction of the conducting grid, the conducting grid being able to be traversed by the accelerated electrons, - a dynode interposed between the cathode and the conducting grid, this dynode being able, for each elementary particle, to produce an avalanche of secondary electrons, this dynode comprising for this purpose several channels, each channel comprising an emissive material, this emissive material being capable, in response to an impact of an electron, of generating, on average, more than one secondary electron, - a reader plate (16; 200) arranged on the side of the conducting grid opposite to the dynode, this reader plate comprising: • an external face arranged in such a manner as to be impacted by the avalanche of secondary electrons, and • electrodes (120; 252) arranged next to one another in a face parallel to or coincident with the external face, • an external face arranged in such a manner as to be impacted by the avalanche of secondary electrons, and • electrodes (120; 252) arranged next to one another in a face parallel to or coincident with the external face, - first sensors able to measure the quantity of electrical charges on the electrodes, - a processing unit capable of determining the location of the avalanche of electrons based on the quantity of electrical charges measured by the first sensors and on the known location of the electrodes, - the detector comprises at least a second sensor , each second sensor being able to measure an electrical signal produced by the secondary electrons when they pass through the conducting grid, and - the processing unit is capable, in addition, of establishing a time of arrival of the elementary particle based on a time referred to as "crossing time" where the electrical signal is measured by the second sensor. <EOS>