Patent Number: 
Section: claims

1. Radiation sensor for dosimetry, comprising:at least one element made out of a radiation detection material, wherein this element has first and second extremities and an axis which passes through these first and second extremities, and the material is configured to emit a luminescence radiation and is transparent to this luminescence radiation; andfirst and second radiation filter screens, wherein the first screen is placed opposite the first extremity of the element and is configured to filter the radiation that reaches the element along a direction close to the axis of the element, the second screen is thicker than the first screen, and this second screen is placed at the periphery of the element and is configured to filter the radiation that reaches the element along a direction close to a direction that is perpendicular to the axis of the element,wherein this sensor is configured to be optically coupled to a flexible light guide configured to collect and convey the luminescence radiation. 2. Sensor according to claim 1, in which the material has an effective atomic number close to 10. 3. Sensor according to claim 1, in which the axis of the element is an axis of symmetry of revolution for this element. 4. Sensor according to claim 1, in which the element is surrounded by a layer for reflecting the luminescence radiation. 5. Sensor according to cliam 1, in which the element has an elongated shape along the element axis and is a cylinder of revolution about this axis and the sensor further comprises a luminescence radiation reflector, wherein the first screen is placed between this reflector and the first extremity of the element, the second extremity of the element configured to be optically coupled to the light guide, the second screen extending along a length of the element from the second extremity of this element, this length depending on the geometry of the element. 6. Sensor according to claim 1, in which the radiation detection material is chosen among the group comprising phosphate type radiophotoluminescent glasses, photo-chromic type luminescent glasses, crystalline radiation detection materials, alumina in the a phase, scintillating crystals and crystals configured to emit an optically stimulated luminescence. 7. Radiation sensor for dosimetry, comprising:at least one element made out of a radiation detection material, wherein this element has first and second extremities and an axis which passes through these first and second extremities, and the material is configured to emit a luminescence radiation and is transparent to this luminescence radiation; andfirst and second radiation filter screens, wherein the first screen is placed opposite the first extremity of the element and is configured to filter the radiation that reaches the element along a direction close to the axis of the element, the second screen is thicker than the first screen, and this second screen is placed at the periphery of the element and is configured to filter the radiation that reaches the element along a direction close to a direction that is perpendicular to the axis of the element,wherein this sensor is configured to be optically coupled to a flexible light guide configured to collect and convey the luminescence radiation, the material is configured to emit said luminescence radiation when the material is optically stimulated, the sensor is thus an optically stimulated luminescence radiation sensor, and the light guide is configured to convey a radiation for optically stimulating the element and for illuminating this element with the optically stimulating radiation. 8. Sensor according to claim 7, in which the material has an effective atomic number close to 10. 9. Sensor according to claim 7, in which the axis of the element is an axis of symmetry of revolution for this element. 10. Sensor according to claim 7, in which the element is surrounded by a layer for reflecting the luminescence radiation. 11. Sensor according to claim 7, in which the element has an elongated shape along the element axis and is a cylinder of revolution about this axis and the sensor further comprises a luminescence radiation reflector, wherein the first screen is placed between this reflector and the first extremity of the element, the second extremity of the element configured to be optically coupled to the light guide, the second screen extending along a length of the element from the second extremity of this element, this length depending on the geometry of the element. 12. Sensor according to claim 7, in which the radiation detection material is chosen among the group comprising phosphate type radiophotoluminescent glasses, photo-chromic type luminescent glasses, crystalline radiation detection materials, alumina in the αphase, scintillating crystals and crystals configured to emit an optically stimulated luminescence. 13. Radiation sensor for dosimetry, comprising:at least one element made out of a radiation detection material, wherein this element has first and second extremities and an axis which passes through these first and second extremities, and the material is configured to emit a luminescence radiation and is transparent to this luminescence radiation;first and second radiation filter screens, wherein the first screen is placed opposite the first extremity of the element and is configured to filter the radiation that reaches the element along a direction close to the axis of the element, the second screen is thicker than the first screen, and this second screen is placed at the periphery of the element and is configured to filter the radiation that reaches the element along a direction close to a direction that is perpendicular to the axis of the element, and the sensor is configured to be optically coupled to a flexible light guide configured to collect and convey the luminescence radiation; anda body comprising a cavity in which the at least one element is located and whose wall is configured to reflect the luminescence radiation, as well as a part comprising a boring whose axis is the axis of the at least one element and whose wall is configured to reflect the luminescence radiation, this part being configured to collect this radiation and to convey the radiation to the entry of the flexible light guide, under an angle that is compatible with the numerical aperture of this flexible light guide, when this guide is coupled to the sensor. 14. Sensor according to claim 13, in which the boring has a conical shape. 15. Sensor according to cliam 13, further comprising a focalisation lens between the at least one element and the boring in the part. 16. Radiation sensor for dosimetry, comprising:at least one element made out of a radiation detection material, wherein this element has first and second extremities and an axis which passes through these first and second extremities, and the material is configured to emit a luminescence radiation and is transparent to this luminescence radiation;first and second radiation filter screens, wherein the first screen is placed opposite the first extremity of the element and is configured to filter the radiation that reaches the element along a direction close to the axis of the element, the second screen is thicker than the first screen, and this second screen is placed at the periphery of the element and is configured to filter the radiation that reaches the element along a direction close to a direction that is perpendicular to the axis of the element, and the sensor is configured to be optically coupled to a flexible light guide configured to collect and convey the luminescence radiation; anda laser configured to emit a radiation for stimulating the element made out of radiation detection material and means for detecting the luminescence radiation emitted by this element. 17. Device according to claim 16, further comprising:a first photo-detector, reflector configured to allow less than 10% of the radiation emitted by the laser to pass towards this first photo-detector and configured to reflect more than 90% of this radiation towards the flexible light guide and a second photo-detector configured to detect the luminescence radiation emitted by the element and conveyed by the flexible light guide, wherein the ratio of signals provided by the first and second photo-detectors allows the variations in the stimulation radiation effectively transmitted to the element to be measured each time this element is interrogated.