Ionizing radiation detector

Abstract

The invention relates to an ionizing radiation detector, the detector comprising a scintillator, a monomer, and a catalyst in which: - the scintillator emits non-ionizing radiation following the absorption of ionizing radiation, - the catalyst catalyzes the polymerization of the monomer following the absorption of the non-ionizing radiation emitted by the scintillator, - the polymer resulting from the polymerization of the monomer has a different color from the monomer. Figure for the abstract: Figure 1

Description

Title of the invention: Ionizing radiation detector technical field

[0001] The invention relates to a method for detecting and a detector of ionizing radiation as well as a method for manufacturing such a detector. STATE OF THE ART

[0002] In the context of any industrial activity carried out under ionizing radiation, particularly in operating or decommissioning nuclear power plants, inspections and maintenance of the various equipment are scheduled. The main risks for workers performing these operations are contamination and irradiation. Irradiation occurs when the worker is exposed externally to radiation emitted by particles located some distance away. Contamination occurs when the worker comes into direct contact with ionizing radiation particles: either through inhalation or ingestion (internal contamination), or through direct skin contact (external contamination). While irradiation ceases when the worker is no longer exposed to the radiation source, this is not the case for contamination.A source of irradiation and contamination for workers is, for example, radioactive material that is dispersed in the air and on the surfaces (floor, pipes, etc.) of the room where the workers are operating during a leak in the circuits, and which contaminates said room.

[0003] In each room, it is necessary to measure the surface activity of any radioactive particles that may be dispersed in the air and on surfaces in order to determine the types of collective protection (containment airlocks, etc.) and individual protection (ventilated, airtight suits, etc.) required to limit the exposure of operators to ionizing radiation emitted by radioactive particles, or radionuclides, and to prevent them from contaminating themselves, whether through internal or external contamination. The activity of a radionuclide is the number of entities of said radionuclide that decay per second, expressed in becquerels (Bq). The surface activity is the activity of the radionuclides present on a surface divided by the Faire value of said surface and is expressed in becquerels per square centimeter (Bq / cm²).

[0004] Measuring surface activity, particularly for alpha emitters (particles consisting of two protons and two neutrons) and beta emitters (electrons or positrons), proves complicated to implement due to the nature of the emitted particles and their physics. Interaction with matter. Alpha particles, due to their mass and high charge, interact with matter via Coulomb interactions, ionizing and exciting atoms and molecules. They have very low penetrating power but are highly ionizing and the most dangerous if ingested or inhaled. Beta particles also interact with matter via Coulomb interactions, ionizing atoms and molecules. These particles are more penetrating but less ionizing than alpha particles.

[0005] The means commonly used in nuclear power plants for detecting radioactive particles contaminating a room are devices called contamination meters. Contamination meters measure a surface activity value (in Bq / cm2) or a count (cps, counts per second), but they do not allow direct visualization of the contamination.

[0006] Several methods are possible for using a contamination meter. Direct measurement involves taking the measurement directly on the surface suspected of being contaminated by particles emitting ionizing radiation, keeping the contamination meter as close as possible to the surface (between a few millimeters and 5 cm, depending on the nature of the contamination). If the surface to be tested is large, it is also possible to scan the surface with the contamination meter, for example, at a speed close to 5 cm / s. Indirect measurement involves taking a smear sample from the surface suspected of being contaminated, then transferring the smear to a room with low gamma background noise to perform the measurement on the smear, maintaining the closest possible distance between the contamination meter and the smear or using a smear autosampler (for example, of the NT200 type).Indirect measurement is necessary in some cases, particularly if the gamma background noise is significant enough to interfere with direct measurements (for gamma background noise greater than approximately 1 pSv / h, said gamma background noise can be caused, for example, by the elements 60Co, 58Co, 110Ag and by a lot of radiation scattered by surfaces, pipes, etc.).

[0007] Such direct or indirect measurements with a contamination meter present several drawbacks. During a direct measurement or screening, as previously mentioned, it is particularly necessary to bring the probe used as close as possible to the surface to be measured. Indeed, a very short distance (a few centimeters to tens of centimeters) in the air is sufficient to stop alpha and beta particles. The detection efficiency therefore decreases rapidly with the distance between the probe and the surface to be measured. Such near-contact measurements require the operator to remain close to the potentially contaminated area, thus exposing them to an increased risk of internal and / or external contamination. Furthermore, Due to its limited scanning speed, screening can be time-consuming, especially if the surface to be monitored is large or has a complex and / or non-planar geometry. This leads to prolonged exposure of those taking measurements to the potentially contaminated environment, thus increasing their risk of contamination. Indirect measurement, on the other hand, requires additional working time in potentially contaminated, irradiated areas, as well as additional donning and doffing steps, consequently increasing the risk of contamination dissemination and / or operator contamination. Finally, measurements using a contamination meter, whether direct or indirect, provide the surface activity value at the time of measurement or sampling. They are not visual, and to understand the temporal evolution of contamination, it is necessary to repeat the measurement several times, with the associated risks..

[0008] Other solutions are proposed for visualizing contamination in a room. For example, an "alpha camera" can be used to detect alpha particles. The detection of these alpha particles is achieved indirectly by measuring the radioluminescence emitted by nitrogen molecules in the air following their ionization by the alpha radiation to be detected. Thus, the emission frequencies of the radioluminescence used by the alpha camera are in the ultraviolet range, between 200 nm and 400 nm, so an optical sensor and data processing are necessary. Access to contamination information is therefore not directly visible to the naked eye. In addition, a power supply is required for the alpha camera to operate.Finally, the use of the alpha camera is restrictive for the user since, to avoid light pollution, measurements must be taken in darkness (with a tarpaulin around the target). Thus, the applications of the alpha camera are mainly aimed at monitoring contamination in glove boxes and monitoring the decontamination of objects (measurements before and after decontamination).

[0009] Another solution involves using radiochromic films comprising a monomer from the diacetylene family embedded in a self-supporting neutral polymer matrix. When this film is directly exposed to ionizing radiation (X-rays, gamma rays, beta rays, or alpha rays), the diacetylene monomer polymerizes. Optical density analysis of the film reveals the darkening of the radiochromic film due to the transition from the uncolored or slightly colored monomer state (pale yellow, pale blue, or white) to the colored polymer state. In the medical field, the darkening of radiochromic films is used, for example, to verify the collimation of beams for radiotherapy. The sensitivity of such radiochromic films depends on the nature of the ionizing radiation. For the detection of alpha particles, the color change of these films is only visible to the naked eye. For activities on the order of a few MegaBecquerels (MBq), such films are not effective enough to detect radioactive leaks on construction sites at industrial facilities where there is a risk of exposure to ionizing radiation, for example, at the site of an operating or decommissioning nuclear power plant. The activity to be detected at these sites is generally between ten Becquerels and a few kilo Becquerels. At such low levels, the color change of these radiochromic films is not visible to the naked eye, and a scanner is required to detect the change. Therefore, the detector's response is neither visual nor immediate. BRIEF DESCRIPTION OF THE INVENTION

[0010] An object of the invention is to design a detector of ionizing radiation, in particular of alpha radiation, which allows the detection by the naked eye of activities between a dozen Becquerels and a few kilo Becquerels (kBq) without requiring the use of an additional reading device.

[0011] The detector must, in particular, allow for the visual alerting of an operator to the presence of radioactive material contaminating a work site at an active or decommissioned nuclear power plant, for example, due to a leak in the circuits, or contaminating the operator himself (contamination on the skin or clothing), the activity of the contamination being between ten and a few kilograms of Becquerels. The detector must also inform the operator quickly of the presence of said contamination. Thus, the operator is not required to approach the area suspected of contamination to take the measurement and is not exposed to said contamination for an extended period without being warned.

[0012] The detector must finally be able to operate autonomously throughout the duration of the construction site until the occurrence of contamination or irradiation due to the presence of radioactive particles emitting ionizing radiation on the site or on the skin or clothing of those involved on said site.

[0013] A first object of the invention therefore relates to an ionizing radiation detector, the detector comprising a scintillator, a monomer and a catalyst, in which: - The scintillator emits non-ionizing radiation following the absorption of ionizing radiation. - the catalyst catalyzes the polymerization of the monomer following the absorption of at least a portion of the non-ionizing radiation emitted by the scintillator, - the polymer, which results from the polymerization of the monomer, has a different color from the monomer.

[0014] According to other optional features of the ionizing radiation detector taken alone or in combination where technically possible:

[0015] - the monomer and the catalyst are contained in the same solid composition, said solid composition preferably in the form of a powder, in particular a powder compacted in a layer arranged on a support;

[0016] - the solid composition is replaceable after use of the detector;

[0017] - the solid composition comprises the monomer in an ordered crystalline form, the catalyst being incorporated into the monomer crystal;

[0018] - the solid composition does not include polymer binder or additives;

[0019] - the scintillator is not included in the solid composition;

[0020] - the scintillator is contained within a solid scintillating layer arranged on the solid layer composition comprising the monomer and the catalyst;

[0021] - the scintillator is contained in a scintillating liquid, the solid composition being insoluble in said scintillating liquid;

[0022] - the detector further comprises a filter film arranged to filter the external ultraviolet radiation detector;

[0023] - the monomer is a diacetylenic monomer of the following formula (I):

[0024] R1-C=CC=C-R2 (I)

[0025] wherein RI and R2 are independently selected from an optionally substituted Cl-Cl 8 hydrocarbon chain, an optionally substituted aryl group and an optionally substituted heteroaryl group, wherein one or more, preferably 1 to 4 methylene group(s) of said hydrocarbon chain are optionally replaced by O, C(O), NH or N-(Cl-C6alkyl);

[0026] - the monomer absorbs at least part of the non-ionizing radiation emitted by the scintillator;

[0027] - the monomer does not absorb at least one wavelength at which the catalyst absorbs non-ionizing radiation and / or the catalyst does not absorb at least one wavelength at which the monomer absorbs non-ionizing radiation from the scintillator;

[0028] - the scintillator comprises barium fluoride BaF2 and / or the catalyst is chosen among the quinones and benzoquinones.

[0029] The invention also relates to a method for detecting ionizing radiation comprising the following steps:

[0030] E0) Supply of a detector as previously described,

[0031] 11) Emission by the scintillator of non-ionizing radiation following absorption of ionizing radiation,

[0032] E2) Polymerization of the monomer, the polymerization being catalyzed by a catalyst, following absorption by the catalyst of at least part of the non-ionizing radiation emitted by the scintillator, the resulting polymer having a different color from the monomer,

[0033] E3) Observation with the naked eye of the color change.

[0034] Finally, the invention relates to a method for manufacturing an ionizing radiation detector comprising the following steps:

[0035] - provide a scintillator emitting non-ionizing radiation following absorption of ionizing radiation,

[0036] - arrange a monomer with respect to the scintillator so that the monomer polymerizes and the device changes color, the resulting polymer having a different color than the monomer.

[0037] - arrange a catalyst relative to the monomer and scintillator so that the catalyst catalyzes polymerization following absorption of at least a portion of non-ionizing radiation emitted by the scintillator. BRIEF DESCRIPTION OF THE FIGURES

[0038] Other features and advantages of the invention will become apparent from the detailed description that follows, with reference to the accompanying drawings, in which:

[0039] - Fig. 1 represents a detector of ionizing radiation emitted by a contamination according to an embodiment of the invention in which the monomer and the catalyst are included in a layered solid composition arranged on a support, the layered solid composition forming the active layer of the detector, the layered solid composition further comprising the scintillator,

[0040] - Figure 2 represents a detector of ionizing radiation emitted by a contamination according to an embodiment of the invention in which the monomer and the catalyst are included in a layered solid composition arranged on a support, the layered solid composition forming the active layer of the detector, and in which the scintillator is included in a separate scintillating solid layer arranged on the active layer,

[0041] - Figure 3 represents a detector of ionizing radiation emitted by a contamination according to an embodiment of the invention in which the monomer and the catalyst are included in a layered solid composition arranged on a support, the layered solid composition forming the active layer of the detector, and in which the scintillator is included in a scintillating liquid, the active layer being immersed in said scintillating liquid.

[0042] For reasons of legibility, the drawings are not necessarily drawn to scale. DETAILED DESCRIPTION OF IMPLEMENTATION METHODS Definitions

[0043] In the following, the term ionizing radiation refers to radiation with a sufficiently high energy level to cause atoms to lose electrons and become ionized, either directly or indirectly. Ionizing radiation can take the form of particles with energies greater than 20 eV, such as alpha or beta particles. These particles, by virtue of their mass and charge, will, upon passing through matter, disrupt the electron configuration of the atoms they encounter and eject electrons from the outer shells of said atoms. This is called direct ionization. Alternatively or additionally, ionizing radiation can take the form of electromagnetic waves such as gamma rays and / or X-rays. The absorption of X-rays and gamma rays by certain atoms causes the ejection of internal electrons from said atoms. These ejected electrons, having non-zero mass and charge, will then ionize other atoms.This is called indirect ionization. These high-energy particles and electromagnetic waves are released from radioactive atomic nuclei, which then disintegrate.

[0044] Alpha radiation is defined as a particle consisting of two protons and two neutrons with a charge of 2+, also identified as a helium nucleus, 4He2+. The mass of the alpha particle is 6.6 x 1027 kg and its mass energy is between 3 MeV and 9 MeV. For example, the decay reaction of Am to Np emits alpha radiation, the largest of which are 5.486 MeV and 5.443 MeV. As another example, the decay reactions of Ra to Rn and then 01Q OOQ OO / 1 Po and U also emit alpha radiation.

[0045] Beta radiation is defined as a particle consisting of a positive charge or a negative charge with a mass of 9.1 x 10³¹ kg, also identified as a positron or an electron, respectively. The energy of the beta particle is between zero and the maximum energy allowed by the beta decay reaction that produces the emission. For example, the decay reactions of ⁶⁰Co to ⁶⁰Ni, of H to He, and of C to N emit beta radiation.

[0046] Gamma radiation is understood to be electromagnetic radiation with wavelengths between 10¹⁴ m and 10¹² m. Gamma radiation is generally emitted during the de-excitation of an atomic nucleus resulting from a decay. For example, the beta decay reaction of ⁶⁰Co to ⁶⁰Ni generates a first gamma radiation at 1.17 MeV and a second gamma radiation at 1.33 MeV. The beta decay reaction of Cs to Ba generates radiation gamma at 661 keV. As another example, the alpha decay reaction of 241Am into 239Nb generates gamma radiation at 60 keV.

[0047] X-rays are understood to be electromagnetic radiation with wavelengths between 10⁸ m and 10¹¹ m. X-rays are emitted during the rearrangement of the electron shells of an atom following the ejection of an electron from an inner electron shell, for example, by collision with a target electron or interaction with gamma radiation. More precisely, during this rearrangement, an electron from an outer electron shell fills the internal vacancy, releasing energy in the X-ray range.

[0048] The term scintillator is understood to mean a molecule emitting non-ionizing radiation following the absorption of at least one type of ionizing radiation (X-rays, gamma rays, alpha rays, beta rays). For example, said ionizing radiation is ultraviolet radiation (wavelength between 100 nm and 400 nm).

[0049] The term catalyst is understood as a molecule capable of increasing the kinetics of a chemical reaction, said catalyst being able to be regenerated or not at the end of the reaction.

[0050] The term contamination refers to the presence of radioactive substances—in other words, substances emitting ionizing radiation—on any surface of a biological nature (e.g., skin or hair) or non-biological nature (e.g., walls or objects in a room, tools or clothing of personnel) or in solids, liquids, or gases where their presence is unintentional and / or undesirable. Ionizing radiation detector

[0051] The invention relates to a detector of ionizing radiation, for example, ionizing radiation emitted by radioactive substances dispersed in a room, or on the skin, hair, or clothing of a human being. Preferably, the invention relates to an alpha particle detector. Location of detector use

[0052] The detector according to the invention can be used in any industrial installation where ionizing radiation is likely to be emitted or where ionizing radiation-emitting contaminants are likely to be disseminated, in order to detect said contamination or radiation and thus protect those working on said industrial application with the appropriate level of protection. The detector according to the invention is of particular interest in nuclear power plants, whether in operation or being decommissioned, where the risk of encountering this type of contamination is significant. The detector according to the invention can also be used in biology or in irradiation testing.

[0053] By way of example, the detector according to the invention can be formulated in solid form as a coating (e.g., gel), film, strip, pellet, flexible collar, or in liquid form. The size and shape of the detector can be adapted to the geometry of the object or surface to be inspected. The coating or strip advantageously allows for the detection of contamination over large areas. The pellet can advantageously be positioned in a hard-to-reach location for smearing.

[0054] In solid form, the detector can be placed directly on construction sites, in areas likely to be contaminated or exposed to ionizing radiation, for example, on the walls of contamination containment airlocks, pipes, valves, taps, etc., which are areas where early detection of contamination is necessary. It can be placed on tools (hammers, screwdrivers, etc.) or complex-shaped construction equipment for which contamination testing is time-consuming (for example, scaffolding). The detector can also be placed on the clothing of site workers to identify which items are contaminated and thus prevent external or internal contamination of the worker. Furthermore, the detector can be used to analyze the transfer of contamination onto workers' clothing during the undressing phase.

[0055] Typically, radioactive particles emitting alpha or beta radiation will be detected by the detector if the detector is positioned at a maximum of approximately 5 cm from said particles, and gamma radiation can be detected up to a few meters from its source. These characteristics make it possible, in particular, to determine the number and location of the detectors best suited to the worksite.

[0056] Alternatively, when the detector includes at least one liquid element, the detector can be used off-site to analyze a smear (sample taken by rubbing on a surface suspected of being contaminated) during indirect measurements.

[0057] General principle of the detection of ionizing radiation by the detector

[0058] When the catalyst "catalyzes" the polymerization of the monomer, it is understood that it initiates and accelerates the polymerization reaction of the monomer.

[0059] When the detector according to the invention is exposed to ionizing radiation, the scintillator absorbs said ionizing radiation and re-emits non-ionizing radiation. The monomer, the catalyst, and the scintillator included in the detector according to the invention are specifically chosen so that the emission spectrum of the scintillator at least partially overlaps the absorption spectrum of the catalyst, this overlap exciting the catalyst and thus initiating the polymerization of the monomer. The absorption of said non-ionizing radiation by the catalyst induces the formation of initiating sites for the polymerization of the monomer, thereby initiating polymerization and consequently the color change of the detector, signaling by the same applies to an operator: the presence of contamination emitting ionizing radiation.

[0060] Preferably, the scintillator's emission spectrum at least partially overlaps the catalyst's absorption spectrum and the monomer's absorption spectrum. Thus, in this embodiment, in addition to being catalyzed by the catalyst, polymerization is also initiated by the monomer's absorption of at least a portion of the non-ionizing radiation emitted by the scintillator. This results in faster and more efficient polymerization, and therefore a color change (i.e., a higher polymerization rate).

[0061] The scintillator typically absorbs a greater proportion of the energy from the incident ionizing radiation than the monomer and catalyst would if they were directly exposed to said ionizing radiation. This is because the scintillator re-emits energy specifically within a range of wavelengths at which the catalyst, and possibly the monomer, also absorbs, so that the energy transfer between the scintillator on the one hand and the catalyst, preferably the catalyst-monomer combination, on the other hand, is efficient. Thus, exposure to ionizing radiation via the scintillator is overall more effective than direct exposure of the catalyst, preferably the catalyst-monomer combination, to said ionizing radiation.In other words, for the same incident ionizing radiation energy, a greater proportion of said incident ionizing radiation is transferred to the catalyst, rather than to the catalyst-monomer association.

[0062] In the presence of the catalyst that generates polymerization initiation sites, the detector's response time and the minimum absorbed dose required to produce a color change observable to the naked eye are reduced, even for alpha radiation. Reading the result then does not require an additional reading device; the result is given directly without correction or interpretation and can be observed remotely. The device is a passive device that does not require an external power supply and can therefore be installed at the start of the project. It quickly informs the operator of the occurrence of contamination without requiring repeated measurements or operator intervention to recharge the device.

[0063] The detection of ionizing radiation is therefore based on the color change of the detector. A color change is understood to be a change visible to the naked eye, that is, one that the eye can detect directly, without the use of other measuring devices. The detector, particularly in its solid form, can be placed by the operator near the area of ​​the worksite that the operator wishes to monitor. During the operation, visual monitoring of the detector allows the operator to remotely and continuously monitor the radiological status of the worksite (corresponding to the absence or presence of radiation). presence of contamination). When contamination occurs, the operator visualizes it with the naked eye by the change in color of the detector: he can start the decontamination of the equipment concerned, or modify the collective and individual protections put in place on the basis of the theoretical studies of site preparation.

[0064] The detector includes a scintillator which, following absorption of ionizing radiation by said scintillator in the presence of contamination emitting said radiation, emits non-ionizing radiation in a given wavelength band. For example, the scintillator emits non-ionizing radiation in the near-visible and / or ultraviolet range. For example, the scintillator emits non-ionizing radiation between 200 nm and 500 nm.

[0065] The detector according to the invention further comprises a monomer whose polymerization is initiated by the catalyst following the latter's absorption of at least a portion of the non-ionizing radiation. Advantageously, the polymerization is also initiated by the absorption by the monomer at at least a given wavelength band of the non-ionizing radiation emitted by the scintillator.

[0066] The monomer used in the detector according to the invention is characterized in that its polymerization results in a change or appearance of color between the monomer state and the polymer state. Thus, if the monomer is colored, the polymer is a different color, so that the presence of ionizing radiation is deduced from the detector by a color change in the detector. Alternatively, if the monomer is not colored, the polymer is colored, and the detection of ionizing radiation by the detector of the invention is based on the appearance of a color change.

[0067] According to a variant of the detector according to the invention, the color of the polymer varies with the rate of polymerization, said rate of polymerization being related to the absorbed dose, so that the detector can further give a quantitative value of the energy or dose (energy per kilogram of matter exposed to radiation) absorbed.

[0068] The detector includes a catalyst that catalyzes the polymerization reaction of the monomer following absorption by said catalyst of non-ionizing radiation at at least one wavelength emitted by the scintillator. For example, the absorption of at least a portion of the non-ionizing radiation by the catalyst causes homolytic cleavage of a bond in said catalyst, thereby generating highly reactive free radicals that initiate radical chain polymerization, which corresponds to type I catalysis. Alternatively, the absorption of non-ionizing radiation by the catalyst causes said catalyst to transition to an excited state, the catalyst in the excited state then interacting with another molecule called a co-catalyst, thereby generating free radicals, which corresponds to type II catalysis. The co-catalyst can be chosen from among amines and... benzophenones. For example, the co-catalyst is chosen from triethylamine, methyldiethanolamine and / or 4,4'-bis(dimethylamino)benzophenone.

[0069] The formation of the polymerization initiation sites from the catalyst and possibly from the monomer following the absorption of the non-ionizing radiation emitted by the scintillator constitutes the kinetically determining step of the polymerization reaction.

[0070] When the monomer does not absorb the non-ionizing radiation emitted by the scintillator, for example because the emission spectrum of the scintillator and the absorption spectrum of the monomer are disjoint, the presence of the catalyst allows the polymerization reaction to be initiated. In other words, in the particular embodiment where the monomer does not absorb the non-ionizing radiation from the scintillator, the detection of the non-ionizing radiation would not be possible without the use of the catalyst.

[0071] When the monomer absorbs the non-ionizing radiation emitted by the scintillator, said absorption also leads to the formation of polymerization initiation sites from the monomer, for example the formation of primary radicals which will then add to other monomeric units.

[0072] However, the formation of initiating sites following the absorption of non-ionizing radiation by the monomer may be inefficient, for example if the monomer absorbs little at wavelengths within the band of wavelengths emitted by the scintillator (for example if the wavelength(s) of the absorption maxima(s) of the monomer are not within the band of wavelengths emitted by the scintillator and / or if the molar extinction coefficient of the absorption maxima of the monomer is low) or if the excited monomer leads little to the formation of initiating sites, so that the polymerization reaction would be overall slow without the joint use of the catalyst.

[0073] In a preferred embodiment in which the monomer absorbs the non-ionizing radiation emitted by the scintillator, the monomer does not absorb at least one wavelength at which the catalyst absorbs the non-ionizing radiation from the scintillator and / or the catalyst does not absorb at least one wavelength at which the monomer absorbs the non-ionizing radiation from the scintillator.

[0074] For example, the scintillator's emission spectrum has two main bands: a first emission band that overlaps with an absorption band of the monomer but does not overlap with the absorption spectrum of the catalyst, and a second emission band that overlaps with an absorption band of the catalyst but does not overlap with the absorption spectrum of the monomer. Alternatively, the absorption spectra of the catalyst and the monomer may be completely distinct from each other, i.e., they have no common absorption wavelengths. Such a variant advantageously allows extension to maximum the absorption range by the monomer / catalyst pair of non-ionizing radiation emitted by the scintillator for a given dose of ionizing radiation absorbed by said scintillator.

[0075] The sensitivity of the detector is defined as, for a source emitting ionized radiation, the minimum activity of the source from which the color change of the detector is visible to the naked eye.

[0076] The sensitivity of the detector is determined by the inventors as follows:

[0077] - the polymerization rate associated with the color change visible to the naked eye is determined by differential scanning calorimetry;

[0078] - from said polymerization rate, the sensitivity is calculated as follows thanks to prior calibration.

[0079] The detector response time is defined as, for a given ionizing radiation source and activity, the time after which the change in color of the detector is visible to the naked eye.

[0080] Typically, the color change is observable to the naked eye on the detector of the invention after an exposure time of between 1 and 8 hours with an alpha radiation source with an activity between 130 kBq and 330 kBq. Such sensitivity makes the detector according to the invention suitable for use on a nuclear power plant operation or decommissioning site for a few hours or a few days. Definition of monomer

[0081] The monomer is advantageously a monomer from the family of diacetylenic compounds. A diacetylenic compound is defined as a compound comprising two C=C triple bonds. The polymerization of diacetylenic monomers can result from a 1,4 addition between the carbon atom Ci of a diacetylenic motif and the C4 atom of the adjacent diacetylenic motif.

[0082] Diacetylenic monomers have the advantage of being colorless or having a pale yellow, white, or slightly bluish color, unlike their polymerized form, which is colored, so that the polymerization reaction produces a color change visible to the naked eye. Furthermore, the color of the polymer typically depends on the degree of polymerization (ranging from light blue for low degrees of polymerization to dark blue, violet, dark violet, black, and even golden black for degrees of polymerization close to saturation). This correlation between color and degree of polymerization can be advantageously exploited by establishing, for each type of UV, X-ray, gamma, beta, and alpha radiation, a calibration linking the degree of polymerization to the energy deposited in the active layer. For example, the detector can be supplied with a color scale indicating to The detector provides quantitative information on the absorbed dose by simply observing the color of the detector and reading the absorbed dose associated with that color on the color scale.

[0083] In addition, diacetylenic monomers have the advantage of polymerizing in the solid state, which makes it possible to avoid the use of a solvent and therefore any potential problems of detector sealing and / or toxicity of said solvent.

[0084] For example, the monomer is a diacetylenic monomer of the following formula (I):

[0085] R'-C=CC=C-R2 (I)

[0086] wherein R1 and R2 are independently selected from an optionally substituted C1-C18 hydrocarbon chain, an optionally substituted aryl group and an optionally substituted heteroaryl group, wherein one or more, preferably 1 to 4, methylene group(s) of said hydrocarbon chain are optionally replaced by O, C(O), NH or N-(Ci-C6alkyl).

[0087] For the purposes of this invention, the term "aliphatic CrCi8 chain" means a saturated monovalent hydrocarbon chain, linear or branched, comprising 1 to 18, in particular 1 to 12, carbon atoms. According to the invention, an aliphatic chain covers substituted or unsubstituted alkyl, alkenyl, or alkynyl groups, linear or branched.

[0088] For the purposes of this invention, the term "alkyl (Ci-C6) group" refers to a monovalent, saturated, linear or branched hydrocarbon chain, preferably comprising 1 to 6 carbon atoms. Examples include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, and hexyl groups.

[0089] For the purposes of this invention, the term "alkenyl group" refers to a monovalent hydrocarbon chain, linear or branched, comprising at least one double bond. Examples include ethenyl, propenyl, allyl, butenyl, pentenyl, and hexenyl groups.

[0090] For the purposes of this invention, the term "alkynyl group" refers to a monovalent hydrocarbon chain, linear or branched, comprising at least one triple bond. Examples include ethynyl, propynyl, butynyl, pentynyl, and hexynyl groups.

[0091] For the purposes of this invention, "aryl" means an aromatic hydrocarbon group, preferably comprising 6 to 10 carbon atoms, and including one or more fused rings, such as a phenyl or naphthyl group. Advantageously, this refers to phenyl.

[0092] For the purposes of this invention, "heteroaryl" means an aromatic group comprising 5 to 10 cyclic atoms, one or more of which are heteroatoms, advantageously 1 to 4 and even more advantageously 1 or 2, such as, for example, sulfur, nitrogen, or oxygen atoms, the other cyclic atoms being carbon atoms. Examples of heteroaryl groups include furyl, thienyl, pyrrolyl, pyridinyl, imidazolyl, triazolyl, tetrazolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, pyrazolyl, oxadiazolyl, thiadiazolyl, pyridazinyl, pyrimidinyl, pyrazinyl, triazinyl, quinolyl, isoquinolyl, quinoxalyl, and indyl.

[0093] By "optionally substituted", for the purposes of the present invention, the group in question is optionally substituted by one or more, preferably 1 to 3 and in particular 1 or 2, substituents chosen from the group consisting of a halogen atom, a Ci-C6 alkyl group, OH, oxo, aryl, heteroaryl, N3, CN NO2, NRa Rb, CORC, CO2Rd, CONReRf, and ORS, in which Ra to Rs represents, independently of each other, H, Ci-C6 alkyl, or aryl.

[0094] Advantageously, R1 and R2 independently represent a C1-C18 hydrocarbon chain, optionally substituted by an aryl group, such as a phenyl, or heteroaryl group, such as a pyridinyl, in which between 1 and 4 methylene groups are optionally replaced by O, C(O), NH or N-(Ci-C6alkyl).

[0095] Preferably, the monomer of formula (I) comprises at least one hydrogen bond donor site and one hydrogen bond acceptor site.

[0096] A hydrogen bond is a non-covalent interaction between an atom bearing a lone pair of electrons and a hydrogen atom bonded to an electronegative atom (N, O, or S). The hydrogen bond donor site is this electronegative atom, and the hydrogen bond acceptor is the atom bearing the lone pair of electrons.

[0097] When the monomer is in crystalline form, these hydrogen bonds formed between an acceptor site of a first monomer of formula (I) and a donor site of a second monomer of formula (I) allow to favor a spatial arrangement of the monomer molecules with respect to each other which is optimal for the topochemical polymerization to take place, in particular via a 1,4 addition between the carbon atom Ci of a diacetylenic motif and the C4 atom of the adjacent diacetylenic motif.

[0098] Thus, the monomer of formula (I) advantageously comprises one or more functions bearing hydrogen bond donor(s) and acceptor(s) site(s) such as the amide function of formula -NH-C(O)-, the urea function of formula -NH-C(O)-NH, the carbamate function of formula -OC(O)-NH, where the -NH- site is a donor of a

[0099]

[0100]

[0101]

[0102]

[0103] first hydrogen bond and where the -C(O)- site is an acceptor of a second hydrogen bond. In a preferred embodiment, the monomer of formula (I) comprises at least one urethane function of formula -NH-C(O)-O-Ci-Ci2 alkyl or -OC(O)-NH-C 1-C12 alkyl. Thus, preferably, R1 and R2 independently represent a CrCi8 hydrocarbon chain, optionally substituted by an aryl group, such as a phenyl, or heteroaryl group, such as a pyridinyl, said hydrocarbon chain being interrupted by one or more urea groups of formula -NH-C(O)O-. More preferably, R1 and R2 independently represent a grouping of the formula -(CH2)mOC(O)-NH-(CH2)n-CH3 or -(CH2)m-NH-C(O)-O-(CH2)n-CH3, m and n each being independently an integer from 0 to 9. R1 and R2 can be identical or different. Preferably, R1 and R2 are identical. Preferably, the monomer of formula (I) is chosen from the group consisting of:

[0104]

[0105] in which n and m are each independently of each other an integer ranging from 1 to 10. More preferably, the monomer of formula (I) corresponds to the following formula (IA):

[0106] In the monomer of formula (I) in crystalline form, the spatial organization is particularly ordered, which makes the topochemical polymerization of said monomer particularly efficient. Such an organization is advantageous for obtaining high degrees of polymerization and thus a color change easily visible to the naked eye, thereby eliminating the need for other additives in the detector, such as an opacifier or a dye. Furthermore, said monomer is not sensitive to the presence of dioxygen, thus eliminating the need for an antioxidant in the detector.

[0107] For example, the monomer (IA) has a pale blue color, while the polymer has a blue color that is darker as the degree of polymerization increases, thus making it possible to quantify the absorbed dose using a color scale.

[0108] Monomers of formula (I) according to the invention typically absorb non-ionizing radiation emitted between 200 nm and 450 nm. More precisely, the absorption spectra of monomers of formula (I) most often exhibit two absorption bands: a primary absorption band with a maximum between 200 nm and 300 nm and a secondary absorption band with a maximum between 300 nm and 400 nm, or between 300 nm and 450 nm if the monomer of formula (I) comprises an aromatic ring. When the monomer of formula (I) is excited in its secondary absorption band, the polymerization kinetics are slow. When the monomer of formula (I) is excited in its primary absorption band, the polymerization kinetics are faster. For example, the monomer (IA) exhibits a primary absorption band with a maximum absorption at 254 nm and a secondary absorption band with a maximum absorption at 365 nm.This secondary absorption band is of very low intensity, so that it is barely or not at all visible on the absorption spectrum of the monomer (IA), but the monomer (IA) still polymerizes when excited at a wavelength of 365 nm. Definition of scintillator.

[0109] The scintillator used in the detector according to the invention is typically chosen from the group consisting of inorganic scintillators such as barium fluoride BaF2, ZnS(Ag) or CaF2(Eu), plastic scintillators such as BC400™, BC404™, BC408™, BC412™ and BC412™ from LuxiuSolutions and ceramic scintillators such as GAGG™ and GPS™ available for example from Epic-cristal, Crystro and Crylink. Advantageously, the scintillator comprises, in particular, barium fluoride (BaF₂). Barium fluoride has the advantage of being radiation-resistant. Furthermore, barium fluoride is advantageously in the form of a transparent crystal. In the detector embodiment described below, which includes a scintillator layer superimposed on an active layer comprising the monomer and the catalyst, such a transparent crystal allows the color change of the active layer resulting from the polymerization of the monomer to be observed directly through said transparent crystal, without having to separate the active layer from the scintillator layer. Barium fluoride is also advantageously transparent to its own light.In other words, the absorption spectrum of barium fluoride does not overlap with its emission spectrum, so the non-ionizing radiation emitted by barium fluoride is not directly reabsorbed by the barium fluoride itself. Such reabsorption would reduce the detector's efficiency, as a smaller proportion of the non-ionizing radiation emitted by the scintillator would reach the catalyst and monomer. Finally, barium fluoride has the advantage of being only slightly hygroscopic. A highly hygroscopic solid scintillator would absorb moisture from the air, and a thin layer of water would adsorb onto its surface. This thin layer of water would absorb at least some of the alpha radiation, preventing it from reaching the scintillator and thus reducing the detector's efficiency.Barium fluoride emits continuously between 170 nm and 460 nm with emission maxima at 195 nm, 220 nm (fast component) and 310 nm (slow component).

[0110] Thus, the monomers used in the detector of the invention, in particular the monomers of formula (I), are advantageously used in conjunction with a scintillator comprising, in particular, barium fluoride, the main absorption band of the monomer of the invention (absorption maximum between 200 nm and 300 nm) overlapping with the emission band of said barium fluoride. More generally, the monomers used in the detector of the invention are advantageously used in conjunction with any scintillator whose emission spectrum exhibits an emission band in the UVC range, for example, an emission band whose absorption maximum is between 200 nm and 300 nm. For example, the monomer of formula (IA) can advantageously be coupled to any scintillator whose emission spectrum exhibits an emission band whose absorption maximum is close to 254 nm. Definition of a catalyst

[0111] The catalyst used in the detector of the invention and as described herein can be chosen so that its absorption spectrum extends over a range of wavelengths between 250 nm and 475 nm. In other words, the catalyst can be chosen to be sensitive to the near-visible (between 400 nm and 475 nm), to UVA (between 320 nm and 400 nm), to UVB (between 280 nm and 320 nm) and / or to the near-UVC (between 250 nm and 280 nm).

[0112] The catalyst used in the detector of the invention is typically chosen from the group consisting of type I or type II catalysts, including benzoquinones, quinones, and their derivatives. Benzoquinones, quinones, and their derivatives are particularly advantageous when coupled to barium fluoride and a diacetylene monomer. Indeed, benzoquinones, quinones, and their derivatives exhibit an absorption band centered around a wavelength between 440 nm and 470 nm that overlaps with the emission spectrum of the BaF2 scintillator and is disjoint from the absorption band around 250 nm of the diacetylene monomers, so that the diacetylene monomer / quinone or benzoquinone duo absorbs a large proportion of the non-ionizing radiation emitted by the barium fluoride.More generally, quinones, benzoquinones and their derivatives can be used in conjunction with any scintillator having an emission band that overlaps with their absorption band between 440 nm and 470 nm.

[0113] The catalyst is present in a small quantity relative to the monomer. For example, the quantity of catalyst is between 0.01% and 10% by mass relative to the mass of the monomer initially present in the detector.

[0114] Solid composition comprising the monomer and the catalyst

[0115] In a preferred embodiment, the monomer and the catalyst are contained in the same solid composition. The solid composition may be in the form of a powder or a mixture of powders. Alternatively, the solid composition may be in the form of a layer or a film, referred to as a layered solid composition, resulting, for example, from the compaction of a powder or a mixture of powders, or from the embedding of one or more powders in a polymer matrix, said layered solid composition constituting the active layer of the detector. The solid-state polymerization of the monomer contained in the solid composition advantageously eliminates the need for a solvent and thus avoids problems related to detector sealing and solvent toxicity.

[0116] The solid composition preferably comprises a powder of monomer crystals, the catalyst being incorporated directly into said monomer crystals. In other words, within the monomer crystals, the monomeric units are arranged in a well-ordered and regular spatial arrangement, The catalyst is very advantageously intercalated between these well-ordered monomeric units. This embodiment of the solid composition very advantageously allows for very close proximity between the catalyst molecules and the monomer molecules, so that all the catalyst molecules are able to initiate polymerization.

[0117] Preferably, the solid composition does not comprise a polymer binder and / or additives other than the monomer and the catalyst. For example, the solid composition does not comprise an opacifier, colorant, or antioxidant. For example, the solid composition consists solely of monomer crystal powder in which the catalyst is incorporated, said powder being compacted into a layer or film as previously mentioned. A solid composition not comprising a polymer binder advantageously avoids diluting the monomer in a neutral polymer matrix, which could lead to the formation of monomer clusters and thus a weaker visual impact of the color change compared to a configuration in which the same quantity of monomer is homogeneously distributed throughout the solid composition.Furthermore, by inserting polymer chains of the polymer binder between the monomers, there is a risk of disrupting the spatial arrangement of the monomers and thus obtaining lower monomer reactivity. Therefore, for the same absorbed dose of ionizing radiation, the use of a polymer binder leads to a less pronounced color change. A solid composition containing no additives other than the monomer and catalyst allows for a detector that is easier to shape.

[0118] As previously mentioned, the catalyst of the detector according to the invention advantageously makes it possible to increase the sensitivity of said detector, so that the color change is visible to the naked eye for absorbed doses of very low ionizing radiation (on the order of a few hundred pGy after about 5 hours of exposure with an activity source on the order of a few tens of Bq / cm2) without the need to add an opacifier and / or a dye to said detector.

[0119] Preferably, the arrangement of the solid composition within the detector allows said solid composition to be replaced after use of the detector without having to discard the other elements of said detector, the use of the detector being understood as an exposure of said detector to ionizing radiation which led to the polymerization of the monomer and the change in color of the detector.

[0120] In the case of a solid layer composition, said solid layer composition may be arranged on a support. The support is, for example, in the form of a polymer film typically comprising polyester, polyethylene, or Polypropylene and / or polyethylene terephthalate. The substrate thickness is, for example, between 10 µm and 2 mm.

[0121] Description of a particular embodiment of the detector in which the scintillator is included in the solid composition which further comprises the monomer and the catalyst

[0122] According to a first particular embodiment of the detector shown in [Fig. 1], the scintillator is contained within a layered solid composition further comprising the monomer and the catalyst, referred to as the scintillating active layer 2, said solid composition itself being able to be arranged on a support 1 as previously described. For example, the scintillating active layer 2 comprises a compacted mixture of a powder comprising the scintillator and a powder of monomer crystals into which the catalyst is incorporated. The powder comprising the scintillator may be a powder of pure scintillator crystals.

[0123] In such an embodiment, the catalyst and optionally the monomer are also capable of absorbing ionizing radiation, in addition to absorbing the non-ionizing radiation re-emitted by the scintillator. This dual absorption makes it possible to generate more active sites and accelerate polymerization. The detector response time is thus reduced.

[0124] In the embodiment shown in [Fig. 1], the scintillator is advantageously located close to the monomer and the catalyst, so that the absorption by the monomer / catalyst pair of the non-ionizing radiation emitted by the scintillator is efficient with minimal losses of said non-ionizing radiation emitted by the scintillator due to geometry. Indeed, the scintillator emits the non-ionizing radiation in all directions of space: the further the scintillator is from the monomer / catalyst association, the smaller the solid angle at which said non-ionizing radiation from the scintillator actually reaches the monomer / catalyst association. In the embodiment shown in [Fig. 1], in which the scintillator is mixed with the monomer / catalyst association, the solid angle is maximized and the geometric losses are limited to edge effects.This embodiment also has the advantage of avoiding interface problems between the active layer and the scintillating layer (detachment, etc.), and the thickness to be traversed by the ionizing and / or non-ionizing radiation is smaller, thus the radiation is absorbed more quickly. There is therefore less energy loss from the radiation. Finally, the fabrication of the device shown in [Fig. 1] requires only one step to deposit the scintillating active layer comprising the scintillator, the monomer, and the catalyst, whereas the embodiment shown in [Fig. 2] requires at least two: a first step to deposit the non-sparkling active layer and a second to deposit the solid scintillating layer.

[0125] In the embodiment shown in [Fig.1], the scintillating active layer 2 has a thickness preferably between 10 pm and 200 pm, in particular between 50 pm and 100 pm.

[0126] Preferably, the detector of [Fig. 1] further comprises means for attaching the scintillating active layer 2 to the support 1 that are reversible. For example, the detector of [Fig. 1] does not include adhesive at the interface between the scintillating active layer 2 and the support 1. Thus, the scintillating active layer 2 is replaceable after use of the detector, and the detector is reused. To this end, the means for attaching the scintillating active layer 2 to the support 1 may include an outer frame. For example, the outer frame may include a back panel, a front panel, and a clamp.When the detector is positioned inside the outer frame, the scintillating active layer 2 is arranged on the support 1 and the overlap of the scintillating active layer 2 and the support 1 is interposed between the back board and the front board of the outer frame, the press of the outer frame applying a clamping pressure of the front board against the back board, so that the scintillating active layer 2 is held fixed against the support 1. Alternatively, the support can form the back board of the outer frame.

[0127] The press includes, for example, at least two wing nuts. According to this embodiment, the rear panel and the front panel each include at least two holes, each hole in the rear panel coinciding with a hole in the front panel when the detector is mounted inside the outer frame. Each wing nut is configured so that, when the detector is mounted inside the outer frame, the wing nut passes through a hole in the front panel and the hole in the rear panel that coincides with the hole in the front panel, and applies clamping pressure to the front panel against the rear panel. The wing nuts advantageously limit the risk of FME (Foreign Material Exclusion), particularly when the detector is intended for use in a reactor building of a nuclear power plant.Indeed, in this type of building, it is important not to lose tools which, if they fall into the reactor, can damage the fuel assemblies of the operating reactor.

[0128] Alternatively, the pressure comprises at least two clamps, for example at least two toggle clasps or at least two butterfly clasps: the clamping pressure of the front board against the rear board is applied by said clamps when the overlap of the rear board and the front board into which the detector is inserted is inserted between the clamps.

[0129] Preferably, the outer frame is configured so that when the detector is mounted inside said outer frame, the color change of the layer The active, shimmering light can be seen directly without removing the frame. For example, the front panel of the outer frame includes a through-hole.

[0130] Description of two embodiments of the detector where the scintillator is not included in the solid composition comprising the monomer and the catalyst

[0131] In a second preferred embodiment, the scintillator is not included in the solid composition. In such an embodiment, the layered solid composition, referred to as the non-sparkling active layer, has a thickness preferably ranging from 100 pm to 1 mm. This thickness range advantageously allows for the absorption of all or almost all of the non-ionizing radiation emitted by the scintillator passing through the non-sparkling active layer, so that no non-ionizing radiation, or a minimal fraction thereof, reaches the substrate. The polymer film of the substrate absorbs this minimal fraction of the non-ionizing radiation, so that there is little or no backscattering of the non-ionizing radiation emitted by the scintillator towards the active layer.

[0132] In such an embodiment, the scintillator does not constitute an additive that dilutes the solid composition. Furthermore, when the scintillator is not included in the solid composition, the ionizing radiation is emitted more homogeneously. Finally, in such a configuration, the scintillator can be changed independently of the active layer.

[0133] a. Scintillator contained in a scintillating solid layer distinct from the solid composition comprising the monomer and the catalyst

[0134] In a particular embodiment of the detector where the scintillator is not included in the solid composition, shown in [Fig. 2], the scintillator is contained within a scintillating solid layer 5 arranged on a layered solid composition comprising the monomer and the catalyst, referred to as a non-sparkling active layer 4. This non-sparkling active layer 4 may itself be arranged on a support 3 as previously described. In this case, the detector comprises, from a rear face to a front face: the support 3, the non-sparkling active layer 4, and the scintillating solid layer 5. For example, the scintillator is in the form of a crystal that constitutes the scintillating solid layer 5.

[0135] When the detector according to the embodiment shown in [Fig. 2] is exposed by its front face to ionizing radiation emitted by contaminants, for example alpha particles, the scintillating solid layer 5 comprising the scintillator absorbs the ionizing radiation and re-emits non-ionizing radiation in all directions, in particular towards the non-scintillating active layer 4 comprising the monomer and the catalyst. The catalyst absorbs this radiation, so as to catalyze the polymerization reaction of the monomer. In order to prevent the loss of the non-ionizing radiation not emitted towards the non-scintillating active layer 4, the detector may further include an external reflective layer enveloping the rest of the detector to reflect more of the non-ionizing radiation emitted by the scintillator back to the non-scintillating active layer 4. For example, the external reflective layer may be a layer of mylar.

[0136] The scintillating solid layer 5 preferably has a thickness ranging from 0.3 mm to 5 mm. Such a thickness of the scintillating solid layer advantageously minimizes the reabsorption by said scintillating solid layer 5 of the non-ionizing radiation emitted by the scintillator, while maintaining a self-supporting scintillating solid layer. The scintillating solid layer 5 is, for example, a scintillator crystal layer that does not include any other compounds. A scintillator crystal layer that does not include any other compounds advantageously avoids diluting the scintillator in the solid layer comprising said scintillator 3 with additives and results in homogeneous emission of non-ionizing radiation.

[0137] The thickness of the support 3 typically ranges from 10 µm to 2 mm.

[0138] Preferably, the detector of [Fig. 2] further comprises means for attaching the non-sparkling active layer 4 to the support 3 and / or to the solid scintillating layer 5, which are reversible. For example, the detector does not include adhesive at the interface between the non-sparkling active layer 4 and the support 3 on the one hand, and at the interface between the non-sparkling active layer 4 and the solid scintillating layer 5 on the other. Thus, the non-sparkling active layer 4 is replaceable after use of the detector, and the detector is reused. To this end, the means for attaching the non-sparkling active layer 4 to the support 3 and / or to the solid scintillating layer 5 may comprise an outer frame as previously described for the embodiment of [Fig. 1].

[0139] The particular embodiment of the detector where the scintillator is not included in the active layer, shown in [Fig.2], advantageously makes it possible to obtain a non-ionizing radiation emitted by the scintillator that is more homogeneous than in the case where said scintillator is included in the active layer.

[0140] b. Scintillator contained in a scintillating liquid

[0141] In another embodiment of the detector where the scintillator is not included in the solid composition, shown in [Fig. 3], the scintillator is contained in a liquid called scintillation liquid 6. For example, the scintillator is liquid and stands alone in its phase. Alternatively, the scintillation liquid 6 may be a commercially available scintillation cocktail such as ULTIMAGOLD™ supplied by PerkinsElmer or PROSAFE™ supplied by Meridian (Hidex). The scintillation liquid 6 may be contained in a bottle 7.

[0142] In the embodiment of [Fig. 3], the detector further comprises a solid composition, said solid composition comprising the monomer and the catalyst, which is insoluble in the scintillating liquid 6. As previously mentioned, the solid composition may be in the form of a powder or a mixture of powders. For example, the solid composition may be in the form of a powder of monomer crystals in which the catalyst is incorporated. The powder or mixture of powders may be directly immersed in the scintillating liquid 6, the powder or mixture of powders being insoluble in said scintillating liquid 6.

[0143] Alternatively, the solid composition may be a layered solid composition optionally arranged on a support as previously described, so that said layered solid composition and said support together form a strip 8. For example, the layered solid composition of the strip 8 is a compacted powder of monomer crystals in which the catalyst is incorporated.

[0144] The thickness of the solid composition of the strip 8 typically ranges from 100 µm to 1 mm, and the thickness of the support 3 typically ranges from 10 µm to 2 mm.

[0145] The strip 8 can be immersed directly in the scintillating liquid 6 contained in the bottle 7, for example by insertion through a slot in said bottle 7. Alternatively, the wall of the bottle 7 may include a recess inward towards the bottle 7, said recess forming a first cavity of the bottle 7 inside a second cavity of the bottle 7, the second cavity being closed and containing the scintillating liquid 6, the first cavity being open and adapted so that the strip 8 can be inserted into said first cavity. Thus, when the strip 8 is inserted into the first cavity, the strip 8 is generally surrounded by scintillating liquid 6 without being directly immersed in said scintillating liquid 6. This embodiment in which the strip is not immersed makes it possible to limit the risk of contamination when removing the strip.

[0146] The embodiment of the detector according to [Fig. 3] advantageously maximizes, for each monomer or catalyst molecule, the probability of the solid composition absorbing non-ionizing radiation emitted by the scintillator, since each monomer or catalyst molecule "sees" the non-ionizing radiation emitted by the scintillator from every solid angle. In the embodiment of [Fig. 2], on the contrary, each monomer or catalyst molecule of the non-scintillating active layer "sees" the non-ionizing radiation emitted by the scintillator from only one side.

[0147] In order to optimize the exposure of the strip to the non-ionizing radiation emitted by the scintillator, the strip may have cylindrical symmetry and the The solid composition can be arranged around the perimeter of the support. For example, the support could be a plastic stick covered with a solid composition.

[0148] Advantageously, the wall of the vial 7 comprises a material that reflects the non-ionizing radiation emitted by the scintillator, for example a wall of Teflon or Mylar, to avoid the loss to the outside of the vial of the non-ionizing radiation emitted by the scintillator inside the vial 7. In the case where the vial 7 includes a recess, the portion of the wall of the vial 7 forming the recess is instead formed of a material transparent to the non-ionizing radiation emitted by the scintillator, so that said ionizing radiation can be transmitted to the strip 8 inserted inside the first cavity.

[0149] When using the detector, a smear from the area suspected of contamination can be introduced into the scintillator liquid 6 in the bottle 7. The scintillator contained in the scintillator liquid 6 absorbs the ionizing radiation emitted by the contaminants present on the smear and generates non-ionizing radiation. This non-ionizing radiation is absorbed by the catalyst and the monomer, which triggers polymerization and results in the color change.

[0150] Strip 8 is preferably replaceable with a new strip, so that after introducing a smear into the scintillating liquid 6 or into the recess of the bottle 7 and coloring the strip 8, the detector can be reused with a new smear.

[0151] External non-ionizing radiation filtering layer

[0152] Regardless of the detector embodiment, said detector preferably comprises an outer layer arranged to filter non-ionizing radiation, for example ultraviolet radiation, external to the devices. Such a non-ionizing radiation filtering layer advantageously protects the active layer from natural and artificial non-ionizing radiation, particularly when the monomer and / or the catalyst are likely to absorb said non-ionizing radiation, which would have the effect of initiating the polymerization reaction and the color change of the detector unrelated to a dose of ionizing radiation potentially absorbed by the scintillator.For example, an ultraviolet filtering layer can be advantageously used when the monomer is a diacetyl compound and the catalyst a compound chosen from among the quinones and benzoquinones because of the high sensitivity of said monomer and of the quinones and benzoquinones to ultraviolet radiation.

[0153] For example, in particular embodiments of Figures 1 and 2, the filtering layer may be a filtering film 9. In the embodiment of [Fig. 2], the filtering film 9 may be arranged on a front face of the scintillating solid layer 5 opposite the non-scintillating active layer 4 of the detector, so that the solid layer scintillating 5 is located between the filter film 9 and the non-scintillating active layer 4. Such an arrangement of the layers advantageously makes it possible not to expose the non-scintillating active layer 4 to non-ionizing radiation other than that emitted by the scintillator.

[0154] In the embodiment of [Fig. 1], the filter film 9 can be arranged on a front face of the scintillating active layer 2 opposite the support 1, so that the scintillating active layer 2 is located between the filter film 9 and the support 1. Such an arrangement of the layers advantageously makes it possible not to expose the scintillating active layer 2 to non-ionizing radiation external to the device.

[0155] The thickness of the filter film 9 preferably ranges from 1 pm to 10 pm. Such a thickness of the filter film 9 advantageously prevents the scattering of ionizing radiation, in particular alpha radiation, towards the scintillator.

[0156] The filter film 9 may be a transparent film comprising a polymer, for example polyester, polyethylene, polypropylene and / or polyethylene terephthalate, and a compound that absorbs non-ionizing radiation, in particular ultraviolet radiation, for example bis(l,2,2,6,6-pentamethyl-4-piperidyl) sebacate and / or methyl l,2,2,6,6-pentamethyl-4-piperidyl sebacate. Such a filter film 9 is advantageously obtained, for example, by a spin-coating, coating or dip-coating process.

[0157] For example, in the embodiment of [Fig. 3], the outer non-ionizing radiation filtering layer can be contained within the walls of the vial 7 containing the scintillating liquid 6, so that the strip 8 inside the vial 7 is not exposed to natural and artificial non-ionizing radiation outside the vial 7 that could distort the measurement in cases where the polymerization of the monomer can be triggered by exposure of the monomer and / or the catalyst to said non-ionizing radiation. For example, the vial 7 is a commercially available tinted vial.

[0158] Specific detector for the detection of alpha radiation

[0159] In a particular embodiment, the detector is specific to alpha radiation, that is to say, it changes color in the presence of alpha radiation and not in the presence of beta radiation and / or gamma radiation.

[0160] For example, the detector is according to the embodiment of [Fig.2] and further includes one or more features described below which give the detector specificity to alpha radiation.

[0161] In particular, in this embodiment, the scintillator is selected from plastic scintillators such as BC400™, BC404™, BC408™, BC412™ and BC412™ and / or from inorganic scintillators such as ZnS(Ag) and CaF2(Eu) and / or the Ceramic scintillators such as the previously mentioned GAGG™ and GPS™ have the advantage of detecting alpha radiation better than other scintillators known to those skilled in the art, even if they are not specific to alpha radiation.

[0162] Additionally or alternatively, the detector is advantageously configured so that the thickness of the scintillating solid layer is between 0.3 mm and 0.5 mm, and the thickness of the non-scintillating active layer is between 20 pm and 50 pm, the substrate being further made of a polished material, for example, glass, Mylar, or aluminum. Indeed, alpha particles will deposit all their energy in the scintillating solid layer to a thickness of at most 50 pm, or even 25 pm. The thicknesses of the scintillating solid layer and the non-scintillating active layer must therefore be as small as possible so that beta particles passing through these layers deposit little energy and so that gamma radiation is not absorbed.A polished substrate advantageously prevents the reflection of beta particles and gamma radiation, so that these particles and radiation are not backscattered into the non-sparkling active layer when they reach the substrate. However, a thickness of the scintillating solid layer less than 0.3 mm would pose manufacturability problems for said scintillating solid layer.

[0163] An embodiment of the detector optimized to be specific to the detection of alpha radiation also makes it possible to obtain a detector that is not very sensitive to the previously mentioned gamma background noise and therefore to avoid the need to implement indirect measurements by the prior preparation of smears and then the analysis of said smears in a low gamma background noise zone. Method for detecting ionizing radiation

[0164] The invention also relates to a method for detecting ionizing radiation, for example a method for detecting ionizing radiation emitted by radioactive substances contaminating a room.

[0165] The method for detecting ionizing radiation includes a preliminary step E0 of supplying a scintillator, a monomer, and a catalyst. The scintillator, monomer, and catalyst are as defined above.

[0166] The method for detecting ionizing radiation further comprises a first step E1 of emission by the scintillator of non-ionizing radiation in at least one wavelength band, following absorption of ionizing radiation by the scintillator. The ionizing radiation is, for example, emitted by a particle emitting ionizing radiation.

[0167] The method for detecting ionizing radiation includes a second step E2 of polymerization of the monomer, the polymerization being catalyzed by the catalyst, following absorption by the catalyst of at least part of the non-ionizing radiation emitted by the scintillator, the resulting polymer has a different color from the monomer.

[0168] Preferably, the polymerization in step E2 is also induced by the absorption by the monomer of at least a portion of the non-ionizing radiation emitted by the scintillator. Thus, the polymerization is jointly initiated by polymerization initiation sites generated from the catalyst and by polymerization initiation sites generated from the monomer. In this embodiment of the detection method, the emission spectrum of the scintillator and the absorption spectrum of the monomer overlap at least partially.

[0169] The ionizing radiation detection method includes a third step E3 of observing with the naked eye a color change when the absorbed dose of ionizing radiation by the detector exceeds a threshold value. The color change may, in particular, be the appearance of a color. The color change is preferentially observable with the naked eye for absorbed doses of ionizing radiation on the order of a few hundred pGy after approximately 5 hours of exposure with an activity source on the order of a few tens of Bq / cm².

[0170] Optionally, the naked-eye observation of the color change can be supplemented by a step E4 of quantifying the absorbed dose. This assessment may include comparing the color of the polymer to a scale relating said color to the absorbed dose. Implementation of direct measures

[0171] In a particular embodiment of the detection method according to the invention, the supply E0 of the scintillator, monomer, and catalyst comprises the placement E0' of said scintillator, monomer, and catalyst in a work zone or on an object of said work zone, followed by the execution E0'' of the work to be carried out on said work zone, so as to perform so-called "direct" measurements. A work zone is understood to mean any area on which maintenance or dismantling work is to be carried out, said area being liable to be contaminated during the course of said work. For example, it could be a maintenance or dismantling site for a nuclear power plant. By way of further example, the detector could be placed on the walls of a room, or on a pipe, a tube, a hammer, scaffolding, or any object of complex shape.

[0172] According to this particular embodiment of the detection method, the observation of the color change with the naked eye in step E3 can be followed by a step additional work stoppage and / or decontamination of the construction site area or contaminated object.

[0173] The detection method according to this embodiment advantageously allows a site operator to continuously monitor, both during work carried out on said site and remotely by simple visual inspection, the radiological state (defined by the absence or presence of contamination) of the site area in which the scintillator, monomer, and catalyst, or the tool on which they are placed, are located. When contamination occurs during the work, the operator is immediately informed of said contamination simply by perceiving the color change without needing to approach to take an additional measurement, thus limiting the risk of contamination of said operator during the measurement operation. Furthermore, the color change allows the operator to immediately adapt their intervention as needed.

[0174] Alternatively or additionally, the E0' arrangement of said scintillator, monomer and catalyst may be made on the clothing of the participants, in the airlocks and / or to monitor the undressing operations of said participants.

[0175] In the particular embodiment of the detection process where the supply E0 of the scintillator, monomer and catalyst includes the disposition E0' of said scintillator, monomer and catalyst in a work zone or on an object of said work site and then the implementation E0' ' of the work to be carried out on said work site, the scintillator, monomer and catalyst are preferably supplied in solid form.

[0176] For example, the scintillator, the monomer and the catalyst are supplied in the form of a detector according to any one of the embodiments previously described where the scintillator is in solid form.

[0177] In the particular case where the detector includes a scintillating or non-scintillating active layer comprising the monomer and the catalyst, for example a layer comprising a compacted powder of monomer crystal in which the catalyst is incorporated, said active layer being reversibly fixed to the other elements of the detector, the detection process may further include a step E4 of changing the active layer which has changed colour by a new uncoloured active layer.

[0178] First embodiment for the implementation of indirect measures

[0179] Alternatively, the supply E0 of the scintillator, monomer and catalyst may include a substep E0' of preparing a smear on an area or tool at a worksite suspected of being contaminated and then a substep E0” of bringing said smear into contact with the scintillator, so that the ionizing radiation absorbed by the The scintillator in step El is the ionizing radiation emitted by the contaminants on the smear. In this case, so-called "indirect" measurements are performed.

[0180] In the particular embodiment of the detection method where the supply E0 of the scintillator, monomer, and catalyst comprises a substep E0' of preparing a smear on an area or tool at a worksite suspected of being contaminated and a substep E0'' of bringing said smear into contact with the scintillator, the scintillator is preferably supplied in liquid form. For example, the scintillator is contained in a liquid, referred to as scintillating liquid, and bringing the smear into contact with the scintillator corresponds to immersing said smear in the scintillating liquid containing the scintillator, for example, until the smear is completely dissolved or for a shorter period sufficient for the contamination to migrate from the smear to the scintillating liquid. More specifically, the scintillating liquid may be contained in a bottle with a cap.The contacting of the smear with the scintillator E0” may include the successive steps of opening the cap, immersing the smear in the scintillator liquid and closing the cap.

[0181] According to this embodiment of the detection method, the supply E0 of the scintillator, monomer, and catalyst may further include a step E0'” of exposing the monomer and catalyst to non-ionizing radiation emitted by the scintillator following contact between the scintillator and the smear, for example, by means of a strip comprising a non-scintillating active layer deposited on a support as previously described. The use of a strip advantageously allows several successive measurements to be performed on the same smear simply by changing the strip.

[0182] According to a particular embodiment of step E0'”, exposing the strip to the non-ionizing radiation emitted by the scintillator includes inserting the strip into a slot in the vial containing the scintillator liquid, so as to immerse said strip in the scintillator liquid. Steps E3 and E4 may be preceded by a step of extracting the strip from the vial through the insert to observe the color change if it is not visible through the walls of the vial (despite exposure to radiation from the outside, the strip will not have time to change color during the very short reading time). In such an embodiment, the active layer must not be soluble in the scintillator.

[0183] According to another embodiment of step E0”', the vial wall comprises a recess as previously described, and step E0’” is a step of inserting the strip into the recess of the vial so that the monomer and the catalyst contained in the non-scintillating active layer of the strip are exposed to the non-ionizing radiation emitted by the scintillator contained in the liquid scintillator contained in the vial without immersion of said strip. Such an embodiment of step EO'' avoids problems of interference between the strip material and the scintillator liquid including the scintillator. In such an embodiment, step EO''' can be performed before or after step EO''.

[0184] Second embodiment for the implementation of indirect measures

[0185] In an alternative embodiment of the indirect measures, the supply EO of the scintillator, monomer and catalyst may include a substep EO' of making a smear on an area or tool of a worksite suspected of being contaminated, a substep EO” of bringing the monomer, scintillator and catalyst into contact and then a substep EO'” of bringing said smear into contact with the scintillator itself in contact with the monomer and catalyst, so that the ionizing radiation absorbed by the scintillator in step 1E1 is the ionizing radiation emitted by the contaminants on the smear.

[0186] For example, the scintillator may be contained within a scintillator liquid itself contained in a bottle, such that the substep EO” of contacting the monomer, scintillator, and catalyst may include mixing the monomer and catalyst powder, for example, monomer crystal powder in which the catalyst is incorporated, with the scintillator liquid, and the substep EO”’ of contacting the smear with the scintillator corresponds to immersing said smear in the scintillator liquid comprising the scintillator, monomer, and catalyst. Again, the contact of the smear may last, for example, until the smear is completely dissolved or for a shorter period sufficient for the contamination to migrate from the smear to the scintillator liquid.

[0187] In such an embodiment, the monomer and catalyst powder must not be soluble in the scintillator. Furthermore, the bottle must be transparent but impermeable to non-ionizing radiation so that the color can be visually detected. However, this embodiment has the advantage of being simple to implement. For example, it does not require a test strip.

[0188] Method for manufacturing an ionizing radiation detector

[0189] The invention extends to a method of manufacturing an ionizing radiation detector comprising a monomer, a catalyst for the polymerization reaction of the monomer and a scintillator, in particular to a method of manufacturing an ionizing radiation detector according to any one of the embodiments previously described.

[0190] More specifically, the method for manufacturing an ionizing radiation detector includes a step a) of supplying the scintillator emitting non-ionizing radiation in at least one band of wavelengths following absorption of ionizing radiation by the scintillator.

[0191] The manufacturing process further includes a step b) of arranging a monomer with respect to the scintillator and a step c) of arranging a catalyst with respect to the monomer and the scintillator such that the catalyst initiates the polymerization of the monomer following absorption by the catalyst of the radiation emitted by the scintillator, the resulting polymer having a different color from the monomer.

[0192] The monomer, catalyst, and scintillator are as previously mentioned. Optionally, the monomer also absorbs the non-ionizing radiation emitted by the scintillator. The arrangement of the monomer relative to the scintillator is therefore such that the monomer also polymerizes due to the absorption by the monomer of the non-ionizing radiation emitted by the scintillator.

[0193] For example, the scintillator can be arranged in a first solid layer called scintillating solid layer distinct from a second layer comprising the monomer and the catalyst called non-sparkling active layer, so that the detector comprises from a rear face to a front face: a support, a non-sparkling active layer and a scintillating solid layer.

[0194] In the following, an example of a method for manufacturing a detector of ionizing radiation is described in which the scintillator is arranged in a scintillating solid layer separate from the non-scintillating active layer comprising the monomer and the catalyst.

[0195] Example of an embodiment of the manufacturing process of a detector in which the scintillator is arranged in a scintillating solid layer separate from the non-scintillating active layer comprising the monomer and the catalyst.

[0196] A1. Formation of the non-sparkling active layer

[0197] Preferably, the non-sparkling active layer comprises the monomer in an ordered crystalline form, the catalyst being incorporated into the monomer crystal.

[0198] When the non-sparkling active layer comprises the monomer in an ordered crystalline form, the catalyst being incorporated in the crystal of the monomer, the arrangement of the catalyst with respect to the monomer preferably includes a recrystallization step so as to obtain a monomer crystal powder in which the catalyst is incorporated.

[0199] According to a particular embodiment of the recrystallization, the monomer and the catalyst are dissolved under heat in a solvent. In an alternative embodiment of the recrystallization, the monomer and the catalyst are melted together without a solvent. Such an embodiment of the recrystallization has the advantage of not involving a potentially toxic solvent that would need to evaporate. This embodiment of the recrystallization is therefore easier to implement and less hazardous.

[0200] A specific example of solvent recrystallization is described below. The solvent is, for example, tetrahydrofuran or chloroform. The resulting solution is then allowed to cool to room temperature, i.e., between 18 °C and 25 °C. The solution is then placed in a cold environment for a period preferably between 30 minutes and 48 hours, for example, for one hour, so as to precipitate a crystal comprising the monomer and the catalyst. During the cooling process, the temperature of the solution is preferably between -20 °C and 5 °C. The solution is then filtered to recover the precipitated crystal. Finally, the crystal is preferably dried under vacuum at room temperature to remove the residual solvent.

[0201] In the following, a particular example of the solvent-free recrystallization method is described. The monomer and the catalyst are melted together without solvent at a temperature between 90 °C and 120 °C. The resulting mixture is then allowed to cool to room temperature, between 18 °C and 25 °C.

[0202] As an alternative to recrystallization, the incorporation of the catalyst into the monomer crystal may include the hot dissolution of the catalyst and the monomer in a solvent followed by the evaporation of said solvent at room temperature, under vacuum or atmospheric pressure.

[0203] The arrangement of the catalyst relative to the monomer further includes a step of formation of the non-sparkling active layer.

[0204] For example, the non-sparkling active layer can be prepared by compacting a powder or a mixture of powders comprising the monomer and the catalyst: the powder or mixture of powders comprising the monomer and the catalyst is deposited on a press support and then the powder is compacted by means of a press, so as to form the non-sparkling active layer.

[0205] Preferably, the powder mixture comprises the monomer crystal powder in which the catalyst from recrystallization is incorporated according to one of the embodiments described above.

[0206] Preferably still, the formation of the non-glittering active layer does not include additional steps of introducing a polymer binder or additives into the powder or powder mixture prior to deposition, so that the non-glittering active layer comprises only the monomer in an ordered crystalline form, the catalyst being incorporated into the monomer crystal.

[0207] A2. Arrangement of the non-sparkling active layer relative to the support

[0208] The non-glittering active layer can be arranged on the substrate by a system reversible mounting, for example by means of an outer frame as previously described. An arrangement between the non-sparkling active layer and the The reversible support advantageously allows the non-sparkling active layer to be replaced after use of the detector while keeping the same support.

[0209] Alternatively, the arrangement of the non-sparkling active layer on the support may include bonding by means of an adhesive which preferably does not degrade under radiation and does not emit parasitic non-ionizing radiation.

[0210] Alternatively, the arrangement of the non-sparkling active layer on the support may include bonding the non-sparkling active layer and the support by heating. In a first step of the heating bonding, the two layers are heated to a temperature close to their melting point. For example, if the non-sparkling active layer is a compacted layer of diacetyl monomer crystal powder, the two layers are heated to a temperature between 90 °C and 120 °C. Then, the two layers are brought into contact and allowed to cool together under pressure.

[0211] The support may be a polymer layer or film comprising, for example, polyester, polyethylene, polypropylene and / or polyethylene terephthalate, the thickness of the support being between 10 pm and 2 mm.

[0212] A3. Arrangement of the scintillating solid layer relative to the non-active layer sparkling

[0213] The scintillator may be supplied in solid form, for example as a scintillating solid layer comprising said scintillator. The scintillating solid layer comprising the scintillator preferably has a thickness of between 0.1 mm and 5 mm. The scintillator may be used in its pure form, such that the scintillating solid layer is a crystal layer of said scintillator.

[0214] According to this embodiment, the arrangement of the monomer and the catalyst with respect to the scintillator is preferably understood as the arrangement of the scintillating solid layer on a face of the non-sparkling active layer opposite the support, so that the detector then comprises from a rear face of said detector to a front face: the support, the non-sparkling active layer and the scintillating solid layer.

[0215] The scintillating solid layer can be arranged on the non-scintillating active layer by reversible attachment means, for example by means of an outer frame as previously described. The reversible attachment means between the scintillating solid layer and the non-scintillating active layer advantageously allow the solid layer composition to be replaced after use of the detector without replacing the solid layer comprising the scintillator. A4. Arrangement of a filter film

[0216] According to this embodiment, the manufacturing process for the ionizing radiation detector may further include a step of arranging a non-ionizing radiation filtering film on a front face of the solid layer scintillating opposite the non-scintilling active layer, so that the detector then comprises from its rear face to its front face: the support, the non-scintilling active layer, the scintillating solid layer and the non-ionizing radiation filtering film.

[0217] Preferably, the external non-ionizing radiation filtering film has a thickness of between 1 pm and 10 pm. Such a thickness of the external non-ionizing radiation filtering film is sufficiently small so as not to block the scattering of alpha radiation towards the scintillating solid layer.

[0218] The arrangement of the external non-ionizing radiation filtering film is advantageously implemented so that no additional material is present between the external non-ionizing radiation filtering film and the scintillating solid layer. In particular, the arrangement of the non-ionizing radiation filtering film preferably does not use any adhesive. Indeed, any additional material can absorb or scatter the ionizing and / or non-ionizing radiation emitted by the scintillator.

[0219] The arrangement of the external non-ionizing radiation filtering film may include the prior preparation of said filtering film, for example by spin-coating, coating or dip-coating, so as to obtain a self-supporting external non-ionizing radiation filtering film.

[0220] By “dip coating” is meant a deposition method where the surface to be treated is immersed and then withdrawn from a solution / suspension at a defined speed (LD Landau, VG Levich, Acta physicochimica, USSR, 17, (1942), 42).

[0221] By "spin coating" is meant a deposition method where a solution / suspension is deposited on the surface to be coated. This same surface is fixed on a spinning wheel which rotates it at a controlled speed which allows the suspension solution to spread over it and wet the whole surface (D. Meyerhofer, J. Appl. Phys., 49, (1978), 3993).

[0222] By coating, we mean a deposition method where a solution / suspension is deposited on the surface to be coated at a controlled speed.

[0223] More specifically, the prior preparation of the external non-ionizing radiation filtering film may include the deposition, by coating, spin-coating, or dip-coating as previously mentioned, onto a substrate, of a solution comprising a polymer and additives that absorb non-ionizing radiation, for example, onto a polytetrafluoroethene substrate, then drying said solution on the substrate to obtain the filtering film, and finally peeling the self-supporting filtering film from the substrate. For example, the solution comprising the polymer and additives is a polyethylene solution comprising the TINUV-2 additive from Stardust.

[0224] Such a method for preparing the filter film advantageously allows precise control of the filter film thickness and yields a filter film with a thickness of less than 10 µm. A filter film with such a low thickness is not commercially available.

[0225] Following the prior preparation of the self-supported external non-ionizing radiation filtering film, the arrangement of the external non-ionizing radiation filtering film preferably includes an additional step of fixing said self-supported external non-ionizing radiation filtering film onto the scintillating solid layer, for example by means of an outer frame as previously described.

[0226] The arrangement of the external non-ionizing radiation filtering film may include preparing said external non-ionizing radiation filtering film directly onto the scintillating solid layer. For example, the preparation of the external non-ionizing radiation filtering film may include deposition by spin-coating, coating, or dip-coating of a solution comprising a polymer and additives as previously described directly onto the surface of the scintillating solid layer. According to this alternative, however, if the adhesion between the scintillating solid layer and the newly formed filtering film is good, the bond between said newly formed filtering film and the scintillating solid layer is permanent.In particular, the arrangement of the external non-ionizing radiation filtering film does not include an additional step of fixing said external non-ionizing radiation filtering film onto the scintillating solid layer.

[0227] In the following, an example of a method for manufacturing a detector of ionizing radiation is described in which the scintillator is arranged directly in the layer further comprising the monomer and the catalyst - called scintillating active layer - so that said detector comprises from a rear face to a front face: a support and a scintillating active layer, the scintillating active layer comprising at least the scintillator, the monomer and the catalyst.

[0228] Example of an embodiment of the manufacturing process of a detector in which the scintillator is arranged in the layer further comprising the monomer and the catalyst - called scintillating active layer.

[0229] Said process may therefore include:

[0230] Bl) the arrangement of the catalyst in relation to the monomer understood for example as the formation by recrystallization of a monomer crystal powder in which the catalyst is incorporated according to one of the recrystallization embodiments previously described;

[0231] B2) the supply of the scintillator in the form of a powder comprising the scintillator, for example a pure crystal powder of said scintillator;

[0232] B3) the arrangement of the scintillator with respect to the monomer and the catalyst included such as the mixture of the powder comprising the scintillator and another powder comprising the monomer and the scintillator, for example monomer crystal powder in which the catalyst is incorporated, followed by the deposition of said mixture on a support and the compaction, for example under a press, of said mixture so as to obtain the scintillating active layer comprising the scintillator, the catalyst and the monomer, called scintillating active layer.

[0233] In the same way as previously described, the support may be a polymer layer or film comprising polyester, polyethylene, polypropylene and / or polyethylene terephthalate, the thickness of the support being between 10 pm and 2 mm.

[0234] In the same way as previously described, the scintillating active layer can be arranged on the substrate by means of a reversible attachment system, such as an outer frame, so that the non-sparkling active layer can be replaced after use of the detector while retaining the same substrate. Alternatively, the scintillating active layer can be arranged on the substrate by bonding with an adhesive, or by heat bonding.

[0235] The method for manufacturing an ionizing radiation detector in which the scintillator is arranged in the solid composition comprising the monomer and the catalyst may further include a step B4) of arranging an external non-ionizing radiation filtering film on a front face of the scintillating active layer opposite the support, such that the detector then comprises, from its rear face to its front face: the support, the scintillating active layer, and the non-ionizing radiation filtering film. The arrangement of the external non-ionizing radiation filtering film on the scintillating active layer may be carried out according to any of the embodiments of said arrangement described above.

[0236] For example, the arrangement of the external non-ionizing radiation filtering film on the scintillating active layer may include the prior preparation of a self-supporting external non-ionizing radiation filtering film according to any of the embodiments previously described and then the fixing of said self-supporting external non-ionizing radiation filtering film on the scintillating active layer by reversible (e.g. an external frame) or non-reversible (e.g. by heating) fixing means.

[0237] For example, the arrangement of the external non-ionizing radiation filtering film on the scintillating active layer may include preparing said external non-ionizing radiation filtering film directly on the scintillating active layer according to any of the embodiments previously described.

[0238] Example of an embodiment of the manufacturing process of a detector in which the scintillator is contained in a scintillating liquid.

[0239] Alternatively, the scintillator may be supplied not in solid form but in liquid form, such as a scintillating liquid comprising said scintillator. ULTIMAGOLD or PROSAFE are examples of commercially available scintillating liquids. The following describes an example of a method for manufacturing an ionizing radiation detector comprising a bottle, said bottle having a slit or indentation as previously described, and the scintillating liquid being disposed inside said bottle, the detector further comprising a strip. The strip comprises a non-scintillating active layer deposited on a support, the non-scintillating active layer comprising the monomer and the catalyst.

[0240] According to this embodiment, the arrangement of the catalyst relative to the monomer is understood as the fabrication of the strip. As previously described, the fabrication of the strip may include:

[0241] - optionally, the preparation by recrystallization of a crystal powder of monomer in which the catalyst is incorporated;

[0242] - the formation and arrangement on the support of the non-sparkling active layer.

[0243] The steps of recrystallizing the monomer crystal powder incorporating the catalyst and of forming and arranging the non-sparkling active layer on the support can be carried out according to any of the embodiments described above. Where the process includes preparing the monomer crystal powder incorporating the catalyst by recrystallization, the formation of the non-sparkling active layer includes compacting said powder, possibly with other powders.

[0244] According to this embodiment, the arrangement of the catalyst with respect to the monomer and the catalyst is understood as filling the bottle with the scintillating liquid and inserting the strip into the slot or recess of the bottle.

[0245] .

Claims

Demands

1. Ionizing radiation detector, the detector comprising a scintillator, a monomer and a catalyst, wherein: - the scintillator emits non-ionizing radiation following absorption of ionizing radiation, - the catalyst catalyzes the polymerization of the monomer following absorption of at least a part of the non-ionizing radiation emitted by the scintillator, - the polymer resulting from the polymerization of the monomer has a different color from the monomer.

2. Detector according to the preceding claim, wherein the monomer and the catalyst are included in the same solid composition, said solid composition preferably being in the form of a powder, in particular a powder compacted in a layer arranged on a support.

3. Detector according to the preceding claim, wherein the solid composition is replaceable after use of the detector.

4. Detector according to any one of claims 2 or 3, wherein the solid composition comprises the monomer in an ordered crystalline form, the catalyst being incorporated into the crystal of the monomer.

5. Detector according to any one of claims 2 to 4, wherein the solid composition does not comprise polymer binder or additives.

6. Detector according to any one of claims 2 to 5, wherein the scintillator is not included in the solid composition.

7. Detector according to the preceding claim, wherein the scintillator is included in a scintillating solid layer (5) arranged on the layered solid composition comprising the monomer and the catalyst.

8. Detector according to claim 6, wherein the scintillator is included in a scintillating liquid (6), the solid composition being insoluble in said scintillating liquid (6).

9. Detector according to any one of the preceding claims, further comprising a filter film arranged to filter external ultraviolet radiation from said detector.

10. Detector according to any one of the preceding claims, wherein the monomer is a diacetylenic monomer of the following formula (I): R'-C=CC=C-R2 (I) wherein R1 and R2 are independently selected from an optionally substituted CrCi8 hydrocarbon chain, an optionally substituted aryl group and an optionally substituted heteroaryl group, wherein one or more, preferably 1 to 4 methylene group(s) of said hydrocarbon chain are optionally replaced by O, C(O), NH or N-(Ci-C6alkyl).

11. Detector according to any one of the preceding claims, wherein the monomer absorbs at least a portion of the non-ionizing radiation emitted by the scintillator.

12. Detector according to the preceding claim, wherein the monomer does not absorb at least one wavelength at which the catalyst absorbs non-ionizing radiation and / or the catalyst does not absorb at at least one wavelength at which the monomer absorbs non-ionizing radiation from the scintillator

13. Detector according to any one of the preceding claims, wherein the scintillator comprises barium fluoride BaF2 and / or wherein the catalyst is selected from quinones and benzoquinones.

14. A method for detecting ionizing radiation comprising the following steps: E1) Providing a detector as defined in claims 1 to 13, E1) Emitting non-ionizing radiation from the scintillator following absorption of ionizing radiation, E2) Polymerizing the monomer, the polymerization being catalyzed by a catalyst, following absorption by the catalyst of at least a portion of the non-ionizing radiation emitted by the scintillator, the resulting polymer having a color different from the monomer, E3) Observing the color change with the naked eye.

15. A method for manufacturing an ionizing radiation detector comprising the following steps: - providing a scintillator emitting non-ionizing radiation following absorption of ionizing radiation, - arrange a monomer relative to the scintillator so that the monomer polymerizes and the device changes color, the resulting polymer having a different color than the monomer, - arrange a catalyst relative to the monomer and scintillator so that the catalyst catalyzes polymerization following absorption of at least a part of the non-ionizing radiation emitted by the scintillator.

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