Improvements in or Relating to Ionising Radiation Detection Apparatus

Abstract

An ionising radiation detector apparatus 1 comprises a laminate 2 having a plurality of substrate layers including a first, second and third substrate layers 4, 5, 6. The first layer 4 comprises a pix

Description

The present invention relates to an ionising radiation detector apparatus and associated method for detecting ionising radiation. The present invention also relates to: an ionising radiation detector system including the ionising radiation detector apparatus; and a method for manufacturing an ionising radiation detector apparatus. In particular, the invention relates to an apparatus, method and system for providing digital images of an inspection site. In the pipeline industry, which includes pipe manufacturing, oil, fuel and gas lines, pipelines on ships, oil rigs, in power stations and submarines, one has to conduct initial and routine inspection of all pipe welds. Such inspections look for cracks, contamination (inclusions), and any defects or weaknesses in the welds, in a non-destructive testing procedure. Pipes are generally round (and not flat like inspection apparatus typically known in the art) and so too the respective welds between adjoining sections of pipes. Further, the pipes I welds are often not easily accessible. As known in the art, there are various inspection techniques. For the purposes of this Application, the focus will be radiographic inspection, including at least X-ray I gamma ray inspection. Radiographic detector apparatus may be generally summarised as radiographic film, flat panel radiographic detectors and CR (computed radiography) plates, each having their own associated disadvantages and / or difficulties of use, which are discussed further below. Those skilled in the art will know that similar problems exist with related inspection techniques. Although more modem techniques exist, the tried and tested traditional radiographic film is still used for inspection of more than 80% of welds. Such film is flexible and can be bent around a pipe or rolled up and put inside the pipe if required. The film is thin and easy to put into confined spaces, but can be scratched or kinked if poorly handled, which leaves artifacts in the image often rendering it useless. Radiographic film is sensitive to light, making its handling more complicated. The film is loaded into light-tight cartridges I envelopes in a darkroom before they can be used for imaging. If these cartridges I envelopes are damaged, the film is rendered useless. The most significant disadvantages are that that the film is single use, and does not provide a digital image. A radiographer has to expose the film, remove it from where inspection has occurred and chemically develop the film before the results can be checked, and all before the radiographer can move to the next weld. This process typically takes 10 to 30 minutes and it is often standard practice to use two films, one behind the other, to provide a better chance of capturing the image required in one attempt. During exposure, the radiographer has to place lead or titanium screens behind the film to prevent radiation (X-rays and / or gamma rays) propagating through the rest of the plant I inspection site, and to also prevent scattered radiation coming back from the screens on to the film or scattered radiation scatter coming back from nearby objects, such as pipes, not the subject of inspection. Image intensifier sheets, being thin sheets of lead, are placed in front and at the back of the film (inside the light-tight cartridge I envelope), so as to filter the radiation to provide an optimum or preferred spectrum, filter out any scattered or reflected radiation from any nearby objects not the subject of inspection, and acts as an image intensifier to reduce the film exposure time. One further and final drawback of radiographic film is a radiographic image created must be scanned to digitise it, or physical copies must be stored in a controlled environment for as long as 70 years, depending upon the subject of inspection. Flat panel radiographic detectors are, as the name suggests, generally flat, albeit some may be slightly curved or have limited flexibility. A traditional flat panel is usually square, may be provided in various dimensions from 10cm by 12cm to 43cm by 43cm, and are, typically, 3cm to 6cm thick. Lead screening is, typically, built into the panel to prevent radiation from passing through the panel, and these types of panels are common in medical applications and non-destructive testing generally. Further, the addition of the lead screening makes the panels heavy. The main advantage to such panels is that they are capable of providing instant digital images; however, the disadvantages often outweigh this advantage in various fields of use. Accordingly, the flat panel radiographic detectors are relatively expensive, heavy and bulky, and do not readily bend around pipes, which generally limits their use to nonconfined spaces. Further, it will be understood that images of curved objects, such as pipes, are distorted when captured on a flat panel detector. CR plates provide a digital alternative; however, they are not true digital detectors. The plates are flexible, and coated with a radiosensitive phosphor layer, and are available in a range of sizes and pixel resolutions. In use, a CR plate may be wrapped around a subject of inspection, for example, half of a pipe and then exposed to radiation from the other side of the pipe. After exposure, the CR plate is removed and taken to a developing station, where the phosphor layer is stimulated with a helium-neon (He-Ne) laser, which makes it emit blue light. The blue light is captured by photo diodes and converted into a digital image. Such a process to develop the image after exposure can take anything from 10 minutes to 30 minutes, depending upon the availability of the specialist equipment required. The CR plate is reusable, and can be cleared by exposing it to high-intensity light - following which it is then ready to be used again. However, CR plates are often used in harsh locations and environments. If these plates are scratched or kinked, they are no longer usable. It is, in such environments, common for a plate to be contaminated with, for example, sand. Contamination on a CR plate affects the image quality, but there is also a risk that the contamination damages the CR plate scanners, which in turn affects all future images and CR plates, until the scanner has been repaired and / or serviced. Although CR plates are designed for circa 1000 exposures, they are almost always damaged much earlier. There is, therefore, a need for a true digital detector which is flexible. The present invention is aimed at providing such a digital detector, whilst minimising the disadvantages associated with prior art detectors / detection techniques. According to a first aspect, the present invention provides an ionising radiation detector apparatus comprising: a laminate having a plurality of substrate layers, the laminate comprising: a first substrate layer comprising: a pixel layer comprising one or more, or a plurality of, pixels for extracting charge from an ionising radiation conversion layer, the pixel layer being capable of converting extracted charge into an electrical signal proportional to ionising radiation exposure of the ionising radiation conversion layer; and a first voltage bias contact, for supplying a voltage to the pixel layer; a second substrate layer comprising the ionising radiation conversion layer, for directly converting incident ionising radiation into charge carriers; and a third substrate layer comprising: a metallisation layer; and a second voltage bias contact, for supplying a voltage to the metallisation layer; wherein the second substrate layer is a deposited layer or coating applied directly on to the first substrate layer; and electrical connection means, operatively connected to: the first voltage bias contact and the second voltage bias contact, for connecting with a power source; and the pixel layer, for conveying the electrical signal to means for processing, conditioning and / or communicating the electrical signal, and / or read-out or display means. Preferably, the third substrate layer is a deposited layer or coating applied directly on to the second substrate layer. Preferably, the resulting laminate is bonded without individual electrical connections. Preferably, the ionising radiation detector apparatus, the laminate and / or the electrical connection means is / are bendable and / or flexible. Most preferably, the deposited layer or coating formation of the laminate provides a flexible or bendable laminate, in which individual substrate layers may flex with respect to one or more adjoining substrate layers. Preferably, the ionising radiation detector apparatus consists of only the laminate and electrical connection means. Preferably, the metallisation layer, ionising radiation conversion layer, and / or pixel layer is / are individually bendable and / or flexible. Preferably, the electrical connection means is individually bendable and / or flexible. Preferably, the ionising radiation detector apparatus and / or the electrical connection means is / are providable as a relatively flat or arcuate structure. Preferably, the ionising radiation detector apparatus is providable in various sizes to suit specific requirements of use, especially sizes to match common radiographic film sizes. Preferably, the ionising radiation detector apparatus is configured to provide a range of ionising radiation detector apparatus, having different pixel sizes and, therefore, different resolutions. Preferably, the apparatus comprises a power source, power conditioning circuits and / or means for connecting with a remote power source. Preferably, the electrical connection means is operatively connected to one or more of: a remotely locatable control module; a power source; a means for processing, conditioning and / or communicating the electrical signal; and / or a read-out means or display means. Preferably, the apparatus comprises a wireless local area network device or short-range wireless communications device, for conveying the electrical signal to a / the remotely located control module comprising: means for processing and / or conditioning the electrical signal; and / or read-out means or display means. Preferably, the means for communicating the electrical signal is through wired or wireless communications, being: a flexible printed circuit I flexible PCB, ribbon cable, local area network, ethernet and / or other wired connectivity means; and / or a wireless local area network device (such as WiFi), short-range wireless communications device (such as Bluetooth™), or other wireless connectivity means. Preferably, the means for conditioning comprises electronics configured for: pixel binning; multiplexing; signal conditioning; buffering; and / or analogue to digital conversion, of the electrical signal. Preferably, the means for processing comprises a processor (optionally a memory) and associated algorithm configured for: pixel binning; signal conditioning; and / or buffering, of the electrical signal. Preferably, the ionising radiation conversion layer comprises a nanoparticle doped organic bulk heterojunction material. Preferably, the ionising radiation conversion layer comprises a first material being a hole carrier material and a second material being an electron carrier material, through which are dispersed a plurality of nanoparticles, preferably comprising high-Z materials. Preferably, the ionising radiation conversion layer has a thickness of about 10pm to about 1mm, wherein the thickness is: preferably about 20pm to about 100pm for greatest flexibility; preferably about 100pm to about 500pm for applications requiring less flexibility but more attenuation; and preferably about 500pm to about 1mm for applications requiring low flexibility but high-attenuation. Preferably, the ionising radiation conversion layer comprises: a network, comprising: a first material for transporting positive electrical charges; a second material for transporting negative electrical charges, the first and second materials being dispersed within the network to form a plurality of electrical junctions; and a plurality of nanoparticles dispersed within the network, wherein said nanoparticles have: a) at least one dimension larger than twice an exciton Bohr radius for said nanoparticles and the at least one dimension being less than 100nm; or b) at least one dimension larger than twice an exciton Bohr radius for said nanoparticles and a further at least one dimension being less than 100nm, and wherein, in use, said nanoparticles convert incoming ionising radiation into free positive and negative electrical charges for transportation by said first and second materials respectively. Preferably, the ionising radiation conversion layer comprises: a device for converting incoming radiation into positive and negative electrical charges, the device comprising: a network comprising: a first semiconductor material for transporting positive electrical charges; and a second semiconductor material for transporting negative electrical charges, the first and second semiconductor materials being dispersed within the network to provide a plurality of electrical junctions, wherein, the network further comprises a plurality of nano-structured agglomerates dispersed within the network, the nano-structured agglomerates comprise a plurality of regions of different relative permittivity capable of creating dielectric inhomogeneities within the nano-structured agglomerates. Preferably, the hole and electron carrier materials comprise P3HT and PC70BM, and the nanoparticles comprise bismuth oxide (most preferably BiaOs). Preferably, the material is a relatively thin ink layer being flexible and / or / bendable. Preferably, one or more pixels of the pixel layer are passive pixels or active pixels, providing an electrical signal relating to current or voltage, proportional to ionising radiation exposure of the ionising radiation conversion layer. Preferably, the pixel layer comprises a flexible substrate, for receipt of the one or more pixels. Preferably, the pixel layer comprises additional electronics configured for: pixel binning; multiplexing; signal conditioning; buffering; and / or analogue to digital conversion. Preferably, the pixel layer is independently flexible and / or bendable. Preferably, the apparatus comprises means for combining the outputs of a plurality of pixels to provide the electrical signal. Preferably, the pixel layer has a thickness of about 20pm to about 100pm, preferably about 30pm to about 70pm. Preferably, the pixel layer comprises a polyimide substrate layer. Preferably, the metallisation layer comprises silver, gold, aluminium, indium tin oxide (ITO) or other conductive materials. Preferably, the metallisation layer has a thickness of about 60nm to about 120nm, preferably about 80nm to about 100nm. Preferably, the apparatus comprises first and second protective layers, providing a protective covering to at least a part or parts of the first and / or third substrate layers. Preferably, the apparatus comprises a protective covering which encapsulates the first to third substrate layers, and, preferably, at least a portion of the electrical connection means. Preferably, the protective layers or protective covering comprises carbon fibre. Preferably, the protective layers or protective covering has a thickness of about 30pm to about 250pm microns, further preferably about 50pm to about 100pm. Preferably, the apparatus comprises means for initiating X-ray image / gamma ray image / other image capture. Most preferably, the means for initiating capture is operatively connected to the electrical connection means through wired or wireless communications. Preferably, in a first configuration, the ionising radiation detector apparatus is an X-ray detector apparatus comprising an X-ray conversion layer, for directly converting incident X-ray radiation into charge carriers. Preferably, in a second configuration, the ionising radiation detector apparatus is a gamma ray detector apparatus comprising a gamma ray conversion layer, for directly converting incident gamma ray radiation into charge carriers. Wherein the ionising radiation detector apparatus is a flexible industrial inspection or medical inspection apparatus, configured to be wrappable around an object or body part for subsequent inspection. Preferably, the power source is a power supply or battery. Preferably, the ionising radiation is X-rays and gamma rays, and the apparatus is configured to detect X-rays and / or gamma rays. According to a second aspect, the present invention provides a method for detecting ionising radiation comprising: locating an ionising radiation source in the environs of an intended inspection site, so as to illuminate the intended inspection site; locating an ionising radiation detector apparatus in the environs of the intended inspection site, so as to detect ionising radiation following illumination of the intended inspection site; the ionising radiation detector apparatus comprising a laminate having a plurality of substrate layers, the laminate comprising: a first substrate layer comprising: a pixel layer comprising one or more, or a plurality of, pixels; and a first voltage bias contact; a second substrate layer comprising an ionising radiation conversion layer; and a third substrate layer comprising: a metallisation layer and a second voltage bias contact; wherein the second substrate layer is a deposited layer or coating applied directly on to the first substrate layer; and electrical connection means, operatively connected to: the first voltage bias contact and the second voltage bias contact; and the pixel layer; the method further comprising: supplying a voltage across the metallisation layer and the pixel layer; illuminating the intended inspection site with ionising radiations; the ionising radiation conversion layer directly converting incident ionising radiation from the illuminated intended inspection site into charge carriers; the pixel layer extracting charge from the ionising radiation conversion layer and converting extracted charge into an electrical signal proportional to ionising radiation exposure of the ionising radiation conversion layer; and conveying, processing, conditioning and / or communicating the electrical signal, displaying or providing a read-out thereof. Preferably, the third substrate layer is a deposited layer or coating applied directly on to the second substrate layer. Preferably, depositing or applying a coating directly provides a bonded laminate without individual electrical connections. Most preferably, the directly deposited or coated formation of the laminate provides a flexible or bendable laminate, in which individual substrate layers may flex with respect to one or more adjoining substrate layers. Preferably, the method comprises an ionising radiation detector apparatus according to the first aspect. Preferably, the intended inspection site is an industrial site, or medical inspection site. Preferably, the method comprises locating the ionising radiation detector apparatus in the environs of an object or body part to be inspected. Most preferably, the method comprises locating the ionising radiation detector apparatus in the environs of a weld to be inspected. Preferably, the method comprises wrapping the ionising radiation detector apparatus around an / the object or body part to be inspected. Most preferably, wrapping the ionising radiation detector apparatus around a weld to be inspected. Preferably, the method comprises: pixel binning; multiplexing; signal conditioning; buffering; and / or analogue to digital conversion, of the electrical signal. Preferably, the method comprises remotely locating any one or more of the following components, being: a control module; a power source; electronics configured for processing, conditioning, and / or communicating the electrical signal, and / or configured for displaying and / or outputting the electrical signal; means for initiating X-ray image capture I image capture; and / or read-out or display means, from the ionising radiation source, so as to reduce any risk of physical and / or radiation damage to those components. Preferably, the method comprises communicating the electrical signal to one or more remotely located components being: a / the control module; electronics configured for processing, conditioning, and / or communicating the electrical signal, and / or configured for displaying and / or outputting the electrical signal; means for initiating X-ray image capture I image capture; and / or read-out or display means, so as to reduce any risk of physical damage and / or radiation damage to those components. Preferably, the power source is remotely located, and connected to the ionising radiation detector apparatus through a flexible printed circuit I flexible PCB, ribbon cable, local area network, ethernet and / or other wired connectivity means. Preferably: a / the control module; the electronics configured for processing, conditioning, and / or communicating the electrical signal, and / or configured for displaying and / or outputting the electrical signal; means for initiating X-ray image capture I image capture; and / or read-out or display means, are remotely located and connected to the ionising radiation detector apparatus through: a flexible printed circuit I flexible PCB, ribbon cable, local area network, ethernet and / or other wired connectivity means; and / or a wireless local area network device (such as WiFi), short-range wireless communications device (such as Bluetooth™), or other wireless connectivity means. Preferably, supplying a voltage across the metallisation layer and the pixel layer, and illuminating the intended inspection site with X-rays I gamma rays can be conducted in either order. Preferably, the ionising radiation is X-rays and gamma rays, and the method is configured to detect X-rays and / or gamma rays. According to a third aspect, the invention provides an ionising radiation detector system comprising: an ionising radiation detector apparatus according to the first aspect; and a wired or wirelessly connected control module, comprising any one or more of the group comprising: a power source; electronics configured for processing, conditioning, and / or communicating the electrical signal, and / or configured for displaying and / or outputting the electrical signal; means for initiating X-ray image capture / image capture; and / or read-out or display means, for providing a digital image of an intended inspection site. Preferably, the control module is locatable remotely from the ionising radiation detector apparatus, locating any one or more of the following: a / the power source; electronics configured for processing, conditioning, and / or communicating the electrical signal, and / or configured for displaying and / or outputting the electrical signal; means for initiating X-ray image capture I image capture; and / or read-out or display means, remote from the ionising radiation detector apparatus and away from potentially harmful radiation. Preferably, the ionising radiation detector system comprises means for storing digital images (especially digital X-ray images I digital gamma ray images), or data relating to the electronic signal. Preferably, the ionising radiation detector system comprises means for combining the outputs of a plurality of pixels to provide a digital image of approx, the surface area of the laminate. Preferably, the ionising radiation detector system comprises a source of ionising radiation. Most preferably, a source of: X-rays; or gamma rays. According to a fourth aspect, the present invention provides a method for manufacturing an ionising radiation detector apparatus according to the first aspect comprising; depositing the second substrate layer directly on to the first substrate layer; or applying a coating of the second substrate directly on to the first substrate layer. Preferably, providing a method for manufacturing an ionising radiation detector apparatus according to the first aspect. Preferably, further comprising subsequently depositing or applying a coating of the third substrate layer directly on to the second substrate layer. Preferably, depositing or applying a coating directly provides a bonded laminate without individual electrical connections. Preferably, the deposited layer or coating formation of the laminate provides a flexible or bendable laminate, in which individual substrate layers may flex with respect to one or more adjoining substrate layers. Advantageously, the present ionising radiation detector apparatus is bendable or flexible, and may be supplied flat or in a curved condition in a range of sizes to suit all needs - to at least match the sizes of common films. Further, the invention provides cost-effective digital images from its flexible ionising radiation detector apparatus. Any difficulties arising from confinement of space for inspection are easily resolved through the detector apparatus / laminate ionising radiation detector being flexible, including the flexible PCB, ribbon cable, local area network, ethernet and / or other wired connectivity means. Further advantageously, the ionising radiation detector apparatus is providable in a range of different pixel sizes and resolutions, to suit all requirements. Use of the ionising radiation detector apparatus of the present invention is intended to replicate the manner of use of film as close as is possible. Radiographers that have been using film for many years would need very little additional training. Advantageously, through removing the majority of the electronic components from the detector apparatus itself, one reduces the risk of mechanical and / or radiation damage to those components. Carbon fibre protective layers reduce the occurrence of scratches and / or other damage, enhancing the utility and lifespan of the detector apparatus. Although the present invention is designed to be as reliable as possible, it is, nevertheless, of low enough cost that, if damaged, it can be replaced in a cost effective manner - cost is certainly reduced through not including lead screening in the detector apparatus and through locating various electronic components separately, and potentially remotely, from interchangeable detector apparatus. A radiographer may be supplied with a single control module, and a plurality of ionising radiation detector apparatus of the present invention, providing a range different sizes of detector apparatus and / or different resolutions, each connectable with the control module. In particular, the radiographer can easily transport all the equipment required to an inspection site and, by way of example only, scan pipes of various diameters - or other objects, body parts, etc. The present invention utilises a direct conversion, ionising radiation conversion layer not requiring a scintillator. As suitable scintillators for the application are typically quite thick, and normally inflexible, the invention provides various improvements over indirect detectors. As for known direct conversion detectors, the present invention is relatively thin, being in at least one embodiment a flexible ink layer. Thus, an apparatus according to the invention is thinner than a traditional direct conversion detector made from a material such as CdTe (cadmium telluride), which is of solid crystal structure making it inflexible. In addition to the ionising radiation conversion layer, the pixel layer is both thin and flexible. Advantageously, physical and / or mechanical damage to various components is reduced by remotely locating those components away from high risk areas associated with an intended inspection site. Any bulky components are also, advantageously, remotely located. Owing to its flexible, thin design, the detector can be easily protected from excessive temperatures through the use of heat-protective cartridges I sleeves. Advantageously, by remotely locating various components, including the electronics, the components are removed from a source of high temperatures and, therefore, protected. Advantageously, and according to operational requirements, the apparatus may be waterproof. The present invention has the following attributes: the detector and remote readout system may be used in a plug and play configuration, where detectors of various different sizes, can be plugged into the same remote readout system; the remote connection method (cables, FPC, etc.) is / are configurable to have different lengths and ratings (for temperature, noise level and / or waterproof rating); and / or if components of the apparatus I system (such as the detector I cabling) are accidentally damaged or worn-out through repeated use, the individual components of the system / apparatus may be economically replaced, and / or replaced independently. Those skilled in the art will know that X-rays and gamma rays are forms of high-frequency (high-energy) ionising radiation. They are typically distinguished by their source, with gamma rays being created by nuclear decay and X-rays originating outside the nucleus. The present invention is directed to all forms of ionising radiation; however, it may be that some configurations of detector apparatus are directed to detecting specific forms of ionising radiation, such as X-rays and gamma rays, in particular. The invention will now be disclosed, by way of example only, with reference to the following drawings, in which: Figure 1 is a schematic drawing of an X-ray detector apparatus; Figure 2 is an exploded, schematic drawing of a laminate structure of the X-ray detector apparatus of Figure 1; Figure 3 is a cross-sectional view along the line A - A of Figure 1; Figures 4a and 4b are schematic drawings of first and second embodiments of X-ray detector system, including the X-ray detector apparatus of Figure 1. Figures 1 to 3 show an X-ray detector apparatus, identified generally by reference 1. The apparatus 1 includes a laminate X-ray detector 2 and a flexible PCB (printed circuit board) 3. The laminate X-ray detector 2 includes a first substrate layer 4, a second substrate layer 5, and a third substrate layer 6. The second substrate layer 5 has been deposited directly onto the first substrate layer 4, and the third substrate layer 6 has been deposited directly onto the second substrate layer 5. As an alternative, the second and third substrate layers 5; 6 may be printed onto a lower-lying layer. Each of the substrate layers 4; 5; 6 is thin and independently flexible, and building up the layers in this manner provides a laminate X-ray detector 2 which retains the flexibility of the individual layers 4; 5; 6. By way of an alternative, the second and third substrate layers 5; 6 may be individually printed directly on to an underlying layer 4; 5. The first substrate layer 4 is a pixel layer 4, which includes a plurality of pixels for extracting charge from an X-ray conversion layer 5 (the second substrate layer 5) and for converting extracted charge into an electrical signal which is proportional to X-ray exposure of the X-ray conversion layer 5. The pixel layer 4 also includes a first voltage bias contact 4a, for supplying a voltage to the pixel layer 4. As mentioned above, the second substrate layer 5 includes the X-ray conversion layer 5, for directly converting incident X-ray radiation into charge carriers - preferably free charge carriers. The third substrate layer 6 is a metallisation layer 6 and further includes a second voltage bias contact 6a, for supplying a voltage to the metallisation layer 6. The laminate X-ray detector 2 is protected and covered by first and second protective layers 7a; 7b, providing a protective covering which envelopes substantially all, if not all, of the laminate X-ray detector 2. The flexible PCB 3 (identified in the claims as electrical connection means) is operatively connected to the first voltage bias contact 4a and the second voltage bias contact 6a, for providing a bias voltage across the X-ray conversion layer 5. The flexible PCB 3 is also operatively connected to the pixel layer 4, for conveying the electrical signal generated by the pixel layer 4 when the X-ray conversion layer 5 is subjected to X-rays. Depending upon the exact configuration, the flexible PCB 3 may connect the apparatus 1 to additional interface electronics, including one or more of the following: a processor and / or controller; signal and / or power conditioning circuitry; memory; power source; and / or communications device(s) - not shown in Figures 1 to 3. The flexible PCB 3 is shown of indeterminate length and two preferred embodiments are disclosed in relation to Figures 4a and 4b, which describe wired and wirelessly connected configurations, respectively. The following provides additional details relating to the substrate layers. The first substrate layer 4, pixel layer 4, has a thickness of, typically, about 30pm to about 70pm, and is flexible. Although theoretically one pixel may be provided, in reality the pixel layer will be provided by a plurality of pixels on a flexible substrate layer, for example a polyimide substrate layer. An individual connection is provided per pixel to the electrode, the material of which could be chosen from the same conductive materials used for the metallisation layer. It can be: a very simple structure with just that / those pixel(s) and a bias voltage contact I electrode; a structure having a single diode per pixel; or a more complicated structure having one or more transistors and one or more capacitors per pixel. Optionally, one can integrate additional electrical components on to the pixel layer 4, or integrate those on to the flexible PCB 3. Such additional electrical components may relate to signal conditioning and buffer circuitry, analogue to digital converters and / or power source or power conditioning circuits. The pixels of the pixel layer 4 may be passive or active pixels. The pixel layer 4 may include additional electronics, relating to: pixel binning; multiplexing; Signal conditioning and buffer circuits; and / or analogue to digital converters; and / or serialisers. In a preferred embodiment, the pixel layer includes a polyimide layer and includes: active pixels, with additional signal conditioning and signal processing capability. The second substrate layer 5 is the X-ray conversion layer 5 and has a thickness of, typically, about 20pm to about 1mm. The X-ray conversion layer 5 may be a nanoparticle doped organic bulk heterojunction (BHJ) material. The BHJ material is a formulation providing hole and electron carrier materials, such as P3HT and PC70BM, which are sandwiched between electrodes - provided by the pixel layer 4 and metallisation layer 6. The nanoparticles are, preferably, high-Z materials, such as bismuth oxide (for example Bi2O3). The exact composition of the materials, ratios and thickness utilised to create the BHJ material, the electrodes and the high-Z nanoparticles may be varied to alter the characteristics of the X-ray conversion layer 5 to suit specific application requirements. In a digital X-ray detector application, the BHJ material (X-ray conversion layer 5) is used in either photodiode or photoresistor mode. Top and bottom electrodes are biased with a voltage between 0 and 200V, or 0V and -200V, creating a potential difference that allows the pixel layer 4 to extract either holes or electrons from the X-ray conversion layer 5 into the pixel layer 4. An optimum bias voltage is dependent upon the thickness of the X-ray conversion layer and intended use of the detector apparatus, but is typically -10V or +10V. However, some applications may require a voltage of ± 12 to 15V. Such a bias voltage is very low compared to other technologies. CdTe and a-Se (amorphous selenium) direct conversion detectors use bias voltages as high as 2KV. Use of a low voltage bias further enables the ability to situate the control electronics separately from the detector, without a potential safety risk of high-voltage connections. In preferred embodiments the thickness of the X-ray conversion layer 5 is: about 20pm to about 100pm for greatest flexibility; about 100pm to about 500pm for applications requiring less flexibility but more attenuation; and about 500pm to about 1mm for applications requiring low flexibility but high-attenuation. The X-ray conversion layer may comprise: a network, comprising: a first material for transporting positive electrical charges; a second material for transporting negative electrical charges, the first and second materials being dispersed within the network to form a plurality of electrical junctions; and a plurality of nanoparticles dispersed within the network, wherein said nanoparticles have: a) at least one dimension larger than twice an exciton Bohr radius for said nanoparticles and the at least one dimension being less than 100nm; or b) at least one dimension larger than twice an exciton Bohr radius for said nanoparticles and a further at least one dimension being less than 100nm, and wherein, in use, said nanoparticles convert incoming ionising radiation into free positive and negative electrical charges for transportation by said first and second materials respectively. Alternatively, the X-ray conversion layer may comprise: a device for converting incoming radiation into positive and negative electrical charges, the device comprising: a network comprising: a first semiconductor material for transporting positive electrical charges; and a second semiconductor material for transporting negative electrical charges, the first and second semiconductor materials being dispersed within the network to provide a plurality of electrical junctions, wherein, the network further comprises a plurality of nano-structured agglomerates dispersed within the network, the nano-structured agglomerates comprise a plurality of regions of different relative permittivity capable of creating dielectric inhomogeneities within the nano-structured agglomerates. The third substrate layer 6, metallisation layer 6, has a thickness of about 60nm to about 100nm, and is flexible. The metallisation layer 6 may be silver, gold, aluminium, indium tin oxide (ITO) or other conductive materials. The flexible PCB 3 is one example of an electrical connection means. By way of an alternative, a ribbon cable, local area network, ethernet and / or other wired connectivity means may be used. Although thickness is less important, it is preferably <100pm, and the electrical connection means is preferably independently flexible, both in terms of its flex and also any connectors. The electrical connection means may have a length of some millimetres or centimetres to some metres depending upon the exact configuration required. Figure 4a shows a first embodiment of X-ray detector system 100, including the X-ray detector apparatus 1 (of Figures 1 to 3) and a control module 101. Figure 4a relates to a X-ray detector system 100 having a wired configuration, and the flexible PCB 3 (of the apparatus 1) is configured to be detachably connectable with the control module 101. It should be noted that, even though wired, the control module 101 may be connected to a range of different X-ray detector apparatus 1, of different size, shape, and / or resolution, and / or different overall configuration for different intended uses. As such, even though this is a wired configuration, X-ray detector apparatus 1 are interchangeable with the control module 101. The control module 101 includes: a power source 102, for supplying power to the control module 101 and, optionally, the detector apparatus 1; interface electronics 103, for processing and / or conditioning the electrical signal, which includes initiating capture of X-ray image data through the X-ray detector apparatus 1; a display or read-out device 104, for displaying an X-ray image of the intended inspection site or other visual output; and communications device 105, being an output for onwards transmission of data and / or images, although it may optionally function to receive data. Figure 4b shows a second embodiment of X-ray detector system 100’, which is based upon the first embodiment of X-ray detector system 100. The system 100’ includes various components which are the same as the first embodiment and, therefore, only the differences will be described in detail. Figure 4b relates to a X-ray detector system 100’ having a wireless configuration, in which the X-ray detector apparatus 1 communicates wirelessly with a modified control module 10T. The flexible PCB 3 of the X-ray detector apparatus 1 is modified to include: a short-range wireless communications device (such as Bluetooth™) 106, for wirelessly communicating with the communications device 105 of the control module 10T; and a designated power source 107, for supplying power to the short-range wireless communications device 106 and the first and second voltage bias contacts 4a; 6a. In use, albeit with slight variation as to how the electrical signal is conveyed to the control module 101; 10T, the X-ray detector systems 100 and 100’ are used in very similar manners. An X-ray source - not shown - is located in the environs of an intended inspection site, so as to illuminate the intended inspection site. For the purposes of this example, the invention will be described as inspecting a weld of a pipe - not shown. The X-ray detector apparatus 1 is located around the pipe, such that the laminate X-ray detector 2 is located around the weld, where it can receive X-ray radiation after passing through the pipe / the weld. In a similar manner to inspection using X-ray film, a lead screen is used behind the X-ray detector apparatus 1, being provided at a surface distal to the pipe. Any difficulties arising from confinement of space for inspection are easily resolved through the detector apparatus 1 I laminate X-ray detector 2 being flexible, including the flexible PCB 3, as this makes access to potentially obscure pipes far easier. The protective layers 7a; 7b protect the laminate X-ray detector from scratches, abrasions, etc. even when flexed, and especially when access to the pipe is through tortuous and / or confined spaces. As the majority, if not all, of the bulky interface electronics have been located in the control module 101; 10T, these components are kept well away from potentially harmful X-rays and protected from mechanical damage. This ensures that only those parts that are essential for providing the electrical signal are provided at the intended inspection site. A bias voltage is applied across the metallisation layer 6 and the pixel layer 4, through the contacts 6a; 4a, respectively, and an X-ray source illuminates the pipe I weld. When an X-ray photon strikes a nanoparticle, the nanoparticle releases multiple electron hole pairs, and the biasing voltage across the X-ray conversion layer pulls the electron hole pairs apart, before they can recombine. Although the exact mechanism by which the pixel layer extracts charge is dependent upon the pixel structure, an example is now provided. In electron collecting mode, the pixel layer 4 collects electrons and these electrons are used to charge or discharge a pixel capacitor. An associated electronics circuit will take a sample measurement of the pixel capacitor value, before resetting the capacitor ready for the next read cycle. The electronic signal created relates to capacitor charge, which is read out as a voltage before being multiplexed into an A / D (analogue / digital) converter. The digital output (electronic signal) from the A / D converter is transmitted to electronic read-out circuitry (such as the display 104 of the control module 101; 10T) via the flexible PCB 3. The display 104 is configured to show a digital X-ray image of the pipe / pipe weld, which can be inspected for abnormalities. As this image is provided practically instantaneously, a number of pipes / pipe welds can be thoroughly inspected in an efficient manner, and / or the images easily stored for subsequent review / compliance. Although the above exemplary embodiments of the present invention have been described and disclosed in the configuration of an X-ray detector apparatus, with an X-ray source, X-ray photons and / or an X-ray conversion layer, those skilled in the art will know that the same principles would apply to the present invention when configured as a gamma ray detector apparatus, with gamma ray source, gamma radiation and / or a gamma ray conversion layer. In an industrial application, the gamma ray source is, typically, a radioactive isotope. In a medical application, the X-ray source is, typically, an X-ray generator, which includes an X-ray tube for providing the X-rays. These two examples are, of course, non-exhaustive. With respect to Figure 4a, the flexible PCB 3 coveys the electrical signal directly to the control module 101, as it is a wired configuration. As for Figure 4b, relating to a wireless configuration, the flexible PCB 3 initially coveys the electrical signal to a short-range communications device 106, which wirelessly communicates the electrical signal to the control module 10T. In the above scenario, the electrical signal is processed and / or conditioned prior to being conveyed to the control module 101; 10T. However, alternatively or additionally, processing and / or conditioning of the electrical signal may be conducted by interface electronics 103 of the control module 101; 101’ after the electrical signal has been conveyed to the control module 101; 101 Ina further alternative, processing and / or conditioning may be conducted by a part of the flexible PCB 3, potentially in addition to other processing and / or conditioning of the signal.

Claims

1.) An ionising radiation detector apparatus comprising:a laminate having a plurality of substrate layers, the laminate comprising:a first substrate layer comprising:5 a pixel layer comprising one or more, or a plurality of, pixels forextracting charge from an ionising radiation conversion layer, the pixel layer being capable of converting extracted charge into an electrical signal proportional to ionising radiation exposure of the ionising radiation conversion layer; and10 a first voltage bias contact, for supplying a voltage to the pixellayer;a second substrate layer comprising the ionising radiation conversion layer, for directly converting incident ionising radiation into charge carriers; and15 a third substrate layer comprising:a metallisation layer; anda second voltage bias contact, for supplying a voltage to the metallisation layer;wherein the second substrate layer is a deposited layer or coating20 applied directly on to the first substrate layer; andelectrical connection means, operatively connected to:the first voltage bias contact and the second voltage bias contact, for connecting with a power source; andthe pixel layer, for conveying the electrical signal to means for25 processing, conditioning and / or communicating the electrical signal,and / or read-out or display means, wherein the laminate is bendable and / or flexible.2.) An ionising radiation detector apparatus as claimed in claim 1, wherein the30 electrical connection means is bendable and / or flexible.3.) An ionising radiation detector apparatus as claimed in claim 1 or claim 2, wherein the electrical connection means is operatively connectable to one or more of:22 10 25a remotely locatable control module;a power source;a means for processing, conditioning and / or communicating the electrical signal; and / or5 a read-out means or display means.4.) An ionising radiation detector apparatus as claimed in any preceding claim, wherein the apparatus further comprises a wireless local area network device or short-range wireless communications device, for conveying the electrical signal to 10 a / the remotely locatable control module comprising: means for processing and / or conditioning the electrical signal; and / or read-out means or display means.5.) An ionising radiation detector apparatus as claimed in any preceding claim, wherein the means for communicating the electrical signal is through wired or 15 wireless communications, being:a flexible printed circuit I flexible PCB, ribbon cable, local area network, ethernet and / or other wired connectivity means; and / ora wireless local area network device, short-range wireless communications device, or other wireless connectivity means.206.) An ionising radiation detector apparatus as claimed in any preceding claim, wherein the ionising radiation conversion layer comprises a first material being a hole carrier material and a second material being an electron carrier material, through which are dispersed a plurality of nanoparticles.257.) An ionising radiation detector apparatus as claimed in any preceding claim, wherein the ionising radiation conversion layer comprises a nanoparticle doped organic bulk heterojunction material.30 8.) An ionising radiation detector apparatus as claimed in claim 6 or claim 7wherein the hole and electron carrier materials comprise P3HT and PC70BM, and the nanoparticles comprise bismuth oxide.22 10 259.) An ionising radiation detector apparatus as claimed in any preceding claim, wherein the one or more, or plurality of pixels comprise: zero to four transistors and zero to one capacitor.5 10.) An ionising radiation detector apparatus as claimed in claim 9, wherein theapparatus comprises means for combining the outputs of a plurality of pixels to provide the electrical signal.11.) An ionising radiation detector apparatus as claimed in any preceding claim, 10 wherein the metallisation layer comprises silver, gold, aluminium, or indium tin oxide (ITO).12.) An ionising radiation detector apparatus as claimed in any preceding claim, wherein, the apparatus comprises first and second protective layers, providing a 15 protective covering to at least a part or parts of the first and / or third substrate layers.13.) An ionising radiation detector apparatus as claimed in any preceding claim, wherein:in a first configuration, the ionising radiation detector apparatus is an X-ray 20 detector apparatus comprising an X-ray conversion layer, for directlyconverting incident X-ray radiation into charge carriers; orin a second configuration, the ionising radiation detector apparatus is a gamma ray detector apparatus comprising a gamma ray conversion layer, for directly converting incident gamma ray radiation into charge carriers.2514.) An ionising radiation detector apparatus as claimed in any preceding claim, wherein the ionising radiation detector apparatus is a flexible industrial inspection or medical inspection apparatus, configured to be wrappable around an object or body part for subsequent inspection.3015.) A method for detecting ionising radiation comprising:locating an ionising radiation source in the environs of an intended inspection site, so as to illuminate the intended inspection site;22 10 25locating an ionising radiation detector apparatus in the environs of the intended inspection site, so as to detect ionising radiation following illumination of the intended inspection site;the ionising radiation detector apparatus comprising a bendable and / or5 flexible laminate having a plurality of substrate layers, the laminatecomprising:a first substrate layer comprising: a pixel layer comprising one or more, or a plurality of, pixels; and a first voltage bias contact;a second substrate layer comprising an ionising radiation conversion10 layer; anda third substrate layer comprising: a metallisation layer and a second voltage bias contact;wherein the second substrate layer is a deposited layer or coating applied directly on to the first substrate layer; and15 electrical connection means, operatively connected to:the first voltage bias contact and the second voltage bias contact; and the pixel layer;the method further comprising:supplying a voltage across the metallisation layer and the pixel layer;20 illuminating the intended inspection site with ionising radiation;the ionising radiation conversion layer directly converting incident ionising radiation from the illuminated intended inspection site into charge carriers;the pixel layer extracting charge from the ionising radiation conversion layer and converting extracted charge into an electrical signal proportional to25 ionising radiation exposure of the ionising radiation conversion layer; andconveying, processing, conditioning and / or communicating the electrical signal, displaying or providing a read-out thereof.16.) A method as claimed in claim 15, wherein the ionising radiation detector30 apparatus is as claimed in any one of claims 1 to 14.17.) A method as claimed in claim 15 or claim 16 comprising locating the ionising radiation detector apparatus in the environs of an object or body part to be inspected.22 10 2518.) A method as claimed in any one of claims 15 to 17, wherein the method comprises remotely locating any one or more of the following: a control module; a power source; electronics configured for processing, conditioning, and / or5 communicating the electrical signal, and / or configured for displaying and / or outputting the electrical signal; means for initiating X-ray image capture I image capture; and / or read-out or display means, from the ionising radiation source, so as to reduce any risk of physical and / or radiation damage to those components.10 19.) A method as claimed in any one of claims 15 to 18, wherein the methodcomprises communicating the electrical signal to one or more remotely located components, being: a control module; electronics configured for processing, conditioning, and / or communicating the electrical signal, and / or configured for displaying and / or outputting the electrical signal; means for initiating X-ray image15 capture I image capture; and / or read-out or display means, so as to reduce any risk of physical and / or radiation damage to those components.20.) An ionising radiation detector system comprising:an ionising radiation detector apparatus as claimed in any one of claims 1 to 20 14; anda wired or wirelessly connected control module, comprising any one or more of the group comprising:a power source;electronics configured for processing, conditioning, and / or communicating the 25 electrical signal, and / or configured for displaying and / or outputting theelectrical signal;means for initiating X-ray image capture I image capture; and / or read-out or display means, for providing a digital image of an intended inspection site.3021.) An ionising radiation detector system as claimed in claim 20, wherein the control module is locatable remotely from the ionising radiation detector apparatus, locating any one or more of the following: the power source; electronics configured for processing, conditioning, and / or communicating the electrical signal, and / or22 10 25configured for displaying and / or outputting the electrical signal; means for initiating X-ray image capture I image capture; and / or read-out or display means, remote from the ionising radiation detector apparatus and away from potentially harmful radiation and / or mechanical damage at a site of inspection.522.) An ionising radiation detector system as claimed in claim 20 or claim 21, wherein the ionising radiation detector system comprises means for combining outputs of a plurality of pixels to provide a digital image of approx, the surface area of the laminate.1023.) An ionising radiation detector system as claimed in any one of claims 20 to22, wherein the detector system comprises a source of: X-rays; or gamma rays.24.) A method for manufacturing an ionising radiation detector apparatus as15 claimed in any one of claims 1 to 14 comprising;depositing the second substrate layer directly on to the first substrate layer; or applying a coating of the second substrate layer directly on to the first substrate layer.20 25.) An ionising radiation detector apparatus as claimed in claim 12, wherein theprotective covering encapsulates the first to third substrate layers.

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