Process for producing particles, comprising the following steps: - introducing into a reaction chamber at least one reaction flow (1, 100, 101, 102, 103, 104, 105, 106) comprising silicon as first chemical element and propagating along a flow direction, - projecting a radiation beam through the reaction chamber intersecting each reaction flow (1, 100, 101, 102, 103, 104, 105, 106) in one interaction zone per reaction flow, in order to form in each reaction flow, particle cores comprising the first chemical element, and - introducing, into the reaction chamber, a second chemical element interacting with each reaction flow (1, 100, 101, 102, 103, 104, 105, 106) in order to cover the particle cores with a layer comprising the second chemical element, each reaction flow (1, 100, 101, 102, 103, 104, 105, 106) being devoid of agent oxidizing the first chemical element, and the cores of particles comprising the first chemical element in non-oxidized form, the number of atoms of the second element introduced relative to the number of atoms of the first element introduced corresponding to a ratio of one atom of the second element introduced per unit of time to at least two atoms of the first element introduced per unit of time, the second chemical element being introduced into the chamber in a gas flow (2; 7) surrounding each reaction flow (1, 100, 101, 102, 103, 104, 105, 106), characterized in that: - the second chemical element is introduced into the chamber in a peripheral gas flow surrounding each reaction flow (1, 100, 101, 102, 103, 104, 105, 106), emitted from several points distributed along a closed curve surrounding each reaction flow (1, 100, 101, 102, 103, 104, 105, 106) and propagating in the direction of each reaction flow, the second chemical element being introduced into the chamber in the peripheral gas flow after the interaction zone of each reaction flow, and/or - it further comprises a step of introducing into the reaction chamber, before the interaction zone of each reaction flow, a confinement gas flow surrounding each reaction flow (1, 100, 101, 102, 103, 104, 105, 106) and propagating along the flow direction, the second chemical element being introduced into the chamber in the confinement gas flow before the interaction zone of each reaction flow. - introducing into a reaction chamber at least one reaction flow (1, 100, 101, 102, 103, 104, 105, 106) comprising silicon as first chemical element and propagating along a flow direction, - projecting a radiation beam through the reaction chamber intersecting each reaction flow (1, 100, 101, 102, 103, 104, 105, 106) in one interaction zone per reaction flow, in order to form in each reaction flow, particle cores comprising the first chemical element, and - introducing, into the reaction chamber, a second chemical element interacting with each reaction flow (1, 100, 101, 102, 103, 104, 105, 106) in order to cover the particle cores with a layer comprising the second chemical element, - the second chemical element is introduced into the chamber in a peripheral gas flow surrounding each reaction flow (1, 100, 101, 102, 103, 104, 105, 106), emitted from several points distributed along a closed curve surrounding each reaction flow (1, 100, 101, 102, 103, 104, 105, 106) and propagating in the direction of each reaction flow, the second chemical element being introduced into the chamber in the peripheral gas flow after the interaction zone of each reaction flow, and/or - it further comprises a step of introducing into the reaction chamber, before the interaction zone of each reaction flow, a confinement gas flow surrounding each reaction flow (1, 100, 101, 102, 103, 104, 105, 106) and propagating along the flow direction, the second chemical element being introduced into the chamber in the confinement gas flow before the interaction zone of each reaction flow.