Abstract: Antistatic compositions are disclosed comprising a hydrophilic binder, surface-active polymer having polymerized oxyalkylene monomers and an inorganic salt characterized in that the salt is selected from the group consisting of inorganic tetrafluoroborates, perfluoroalkyl carboxylates, hexafluorophosphates and perfluoroalkyl sulfonates.

Abstract: A silver halide photographic light-sensitive material is disclosed. The material is comprised of a support base having provided thereon a hydrophilic colloid layer and a silver halide emulsion layer. The silver halide emulsion layer contains tubular silver halide grains having a diameter at least 3 times their thickness and also contains a compound represented by general formula (I) or (II): ##STR1## the substituents are defined within the specification. The material obtains the advantages of utilizing tabular silver halide grains while having a reduced dependents of its photographic properties on development processing conditions which normally effect materials containing tabular silver halide grains.

Abstract: A layered structure for use in an X-ray membrane (pellicle) mask or a vacuum window is provided in which an intermediate amorphous layer such as silicon dioxide is grown on a silicon substrate which provides a stress relief medium and surface properties which enhance and improve subsequent process layers by breaking the epitaxial nature of these later deposited layers. Upon subsequent deposition of an inorganic overcoat, such as SiC, on the intermediate amorphous layer, the overcoat produces a nearly defect-free layer with a substantially reduced stress of suitable quality for X-ray lithography mask fabrication. Furthermore, additional alternating layers of a silicon carbide film and an intermediate inorganic layer, such as silicon nitride, can be deposited to obtain an even smoother silicon carbide surface and stronger structure.

Abstract: X-ray energy-difference images are obtained simultaneously by exposing a body to a broad energy spectrum x-ray beam while a radiographic film package is disposed between front and rear x-ray intensifying screens. The film package has two superimposed films with a light-opaque sheet between them. The front screen, on which the polyenergetic image beam emerging from the body is incident, is excited to luminescence by x-ray photons predominantly in one energy band and the rear screen is excited predominantly by photons in another band. The light opaque sheet preferably contains x-ray filter material for additional filtering of photons to increase the fraction of photons at said other band to which the rear screen is sensitive. A shadowgraph of a marker is formed on the film emulsions during x-ray exposure to aid in matching congruent picture elements on each film when the developed films are being read out to obtain signals corresponding to their intensities.

Abstract: A negative type resist for high energy beam such as electron beam, X-rays or the like made from quinone diazide ester of an oligomer having a polymerization degree of 1-20, and a process for forming a pattern with the same type resist.

Abstract: A method for manufacturing structures having dimensions in a range of 1 .mu.m and below in a layer of material by applying an auxiliary layer consisting of metal or metal oxide on the layer to be structured and utilizing a lacquer mask to structure the auxiliary layer to form a mass therein for the etching of the layer to be structured, characterized by passivating the auxiliary layer by applying a protective layer to prevent oxidizing of the auxiliary layer until a desired time. The protective layer can be gold or platinum and the auxiliary layer can be selected from a group consisting of titanium, hafnium, zirconium, vanadium, chromium, manganese, aluminum, niobium and tantalum. The method is particularly useful to manufacuture absorber structures of X-ray masks that are used in microelectronics.

Abstract: A silver halide photographic light-sensitve material is disclosed. The material is comprised of a transparent support having provided on one side of the support at least two silver halide emulsion layers and a surface-protecting layer. One of the two silver halide emulsion layers is a tabular silver halide emulsion layer containing tabular silver halide grains having a diameter at least five times the thickness of the grains. The other silver halide emulsion layer is a non-tabular silver halide emulsion layer containing non-tabular silver halide grains. The tabular silver halide emulsion layer is positioned closer to the support than the non-tabular silver halide emulsion layer, and the non-tabular silver halide emuslion layer is positioned closer to the support than the surface-protecting layer. The material may include two similar silver halide emulsion layers and a surface-protecting layer on the opposite side of the support.

Abstract: Antistatic compositions are disclosed comprising a hydrophilic binder, surface-active polymer having polymerized oxyalkylene monomers and an inorganic salt characterized in that the salt is selected from the group consisting of inorganic tetrafluoroborates, perfluoroalkyl carboxylates, hexafluorophosphates and perfluoroalkyl sulfonates.

Abstract: A method for tensioning a thin film on a support ring to achieve an optically flat membrane. The support ring is optically flat with a slight bevel at its outside edge where the membrane is epoxied to the support ring.

Abstract: A process for forming a self-aligned resist mask over a surface of an alumina ceramic substrate having a conductive molybdenum pattern at said surface by first blanket coating the surface with a negative resist sensitive to aluminum emitting X-rays. A blanket dosing of the substrate with resist insensitive X-rays occurs to induce X-ray emission by the aluminum of said substrate to penetrate said resist. The aluminum X-ray emission is screened by said molybdenum pattern at the surface and the resist adjacent the surface molybdenum pattern is penetrated by the aluminum X-ray emission. The resist is developed for removal thereof over the molybdenum pattern while retaining the resist doped by said aluminum X-ray emission. Further metalization can be accomplished by evaporation or sputtering to blanket coat the developed resist with a conductive metal followed by removal of the resist with the metal coating thereon such that the metal coating is retained on the molybdenum pattern.

Abstract: A laser beam scanner system records medical information on a direct-read-after-write optical data storage strip. The strip is adhered to a medium containing a picture, such as X-ray pictures, CAT-scan pictures, ultrasonic or NMR images, or microscope photos of tissue samples. The strip may record information such as a description or diagnosis related to the picture for archival storage.

Abstract: Silver halide photographic material for radiography comprising a transparent support having a hydrophilic colloid layer coated on each side thereof said layer comprising (a) photosensitive silver halide grains, (b) silver halide grains having surfaces covered with a solubility reducing agent and which, in the absence of said solubility reducing agent, are more soluble in a material capable of dissolving silver halide than said (a), said (b) having a sensitivity to light generally less than 1/10 that of said (a), and (c) physical development nuclei, wherein the molar ratio of (a) to (b), based on the silver content of each, is between 1:0.1 to 1:0.8 on each side of said support and the total silver content of (a) and (b) is from 1 to 8 g/m.sup.2.

Abstract: A lithographic process utilizing soft x-rays or ions to achieve high resolution is disclosed. The process is particularly useful and semiconductor processing where high resolution is required to achieve a high density. The process utilizes a mask to selectively expose a photoresist to soft x-rays or flood beams of ions. The mask comprises a thin metallic foil supported by a frame such that the foil is in tension. The frame includes optical alignment keys. A second patterned layer of metal is affixed to the foil to form areas which are nontransparent to the soft x-rays or flood ion beams for delineating the elements of a semiconductor circuit, for example. This permits the mask to be optically aligned using conventionally techniques with high resolution being achieved do to the short wavelength of the x-ray radiation or the ion beams.

Abstract: A mask substrate for use in X-ray lithography formed of a composite, X-ray transparent member which is stretched over a fixture to a predetermined tension and then adhered to a borosilicate glass ring. In accordance with a preferred embodiment, the composite member includes a film of polyborane which has been grown in compression, onto which a polyimide is coated. The polyborane film is grown on a silicon wafer, coated with the polyimide, after which the central area of the wafer is etched away. The borosilicate glass is adhered to the polyimide side of the composite, leaving the tensioned polyborane surface open for the application of an X-ray absorptive pattern thereto to define a complete mask structure suitable for use in X-ray lithography.

Abstract: Novel copolymers having a weight average molecular weight of 500 to 5,000,000 and comprising 1 to 99% by weight of a recurring unit represented by the formula (I), 1 to 99% by weight of a recurring unit represented by the formula (II) and 0 to 98% by weight of a recurring unit represented by the formula (III): ##STR1## wherein R.sup.1 is a hydrogen atom or a methyl group; X is a hydrogen atom, a methyl group or a phenyl group; Y is a hydrogen atom, a halogen atom, a methyl group, a phenyl group or a cyano group; and Z is a phenyl group, a phenyl group substituted by at least one alkyl group having 1 to 8 carbon atoms, a polycyclic aromatic hydrocarbon group having 10 to 20 carbon atoms, a cyano group, --COOR.sup.2 (in which R.sup.2 is an alkyl group having 1 to 20 carbon atoms or an aromatic hydrocarbon group having 6 to 14 carbon atoms), --COR.sup.3 (in which R.sup.

Abstract: Film packages for obtaining x-ray energy-difference images simultaneously by exposing a body to a broad energy spectrum x-ray beam. One package embodiment has two radiographic films joined at at least two edges to form a pocket in which a light-opaque sheet is inserted during the x-ray exposure. The package is disposed between front and rear x-ray intensifying screens during the exposure. The front screen on which the broad energy image is incident is excited to luminescence predominantly by x-ray photons in one energy band and the rear screen by photons in another band to thereby produce the difference images. The opaque sheet may contain x-ray filter material. A reflective sheet is substituted in the pocket for said opaque sheet during readout of the intensities of corresponding picture elements. Another film package embodiment is laminated and unitary and has a double-sided reflective sheet in the middle, a light-opaque coating on each reflective surface and a photosensitive emulsion on each coating.

Abstract: A spectrally sensitized silver halide photographic element capable of producing a stable, viewable silver image on development and fixing out is disclosed. The latent image forming silver halide grains in the image recording emulsion layer or layers of the photographic element are silver bromide, chloride, or chlorobromide grains. At least one of the image recording emulsion layers contains spectrally sensitized tabular grains. Located in proximity to the spectrally sensitized tabular grains are relatively fine high iodide silver halide grains capable of being dissolved during fixing out.

Abstract: The invention is an improved system for the rapid development of X-rays. The system is particularly useful for the development of dental-type X-rays. The system consists of an enclosed sealed pouch-like holder for the unexposed X-ray film, a special pocket built into the pouch-like holder for guiding an injection needle during operation of the device, a sealant within the specific pocket through which the injection needle is inserted, and a syringe-type injector with injection needle and a supply of monobath solution (a combined developer and fixer solution).

Abstract: Photoresist compositions are provided whereby metals are incorporated into the resist by providing a photoresist composition comprising the reaction product of an organic resist which has at least one reactive hydroxyl or amino group with an organometallic compound. Also provided is a process for generating a pattern on a substrate by coating the substrate with a thin film of the photoresist composition which comprises the reaction product of the organic resist which has at least one reactive hydroxyl or amino group with an organometallic compound. The photoresist compositions are particularly suitable for use in diazo-type electron beam procedures.

Abstract: An X-ray absorber layer in the form of single layer of high melting point metal such as Ta, W is formed with granular crystal grains on a mask substrate, so that an internal stress of the layer is reduced. A fine pattern is formed from the absorber layer by reactive sputter etching using CBrF.sub.3 gas as an etchant, so that an X-ray absorber pattern is formed on the mask substrate. The X-ray lithography mask thus fabricated has a fine pattern such as submicron pattern with a high degree of pattern contrast and a high dimensional accuracy.

Abstract: A photographic material suited for the production of (an) azine dye image(s), and having at least one silver halide emulsion layer and/or a separate layer in water-permeable relationship with such an emulsion layer which contains:(1) a heterocyclic hydrazone compound,(2) a phenol, naphthol or active methylene coupler compound capable of forming on oxidative coupling with compound (1) an azine dye,(3) an electron transfer agent or ETA-compound capable of forming a positively charged semiquinone on oxidation with exposed silver halide,(4) a reducing agent capable of reducing the thus-formed semiquinone in acidic medium, and having in the pH range of 2-5, a polarographic half-wave potential (E 1/2) which is at least 40 mV more negative (according to the European Convention) than the polarographic half-wave potential of the ETA-compound in the same pH range, said material being suited for processing with a simple aqueous alkaline liquid, and(5) an acidic medium.

Abstract: There is disclosed an image-formable resinous composition comprising a poly(olefinsulfone) and a matrix polymer, in which the matrix polymer being a novolac phenol resin obtained from:(1) m-cresol and p-cresol as main components, the molar ratio of m-cresol/p-cresol being within the range from 40/60 to 55/45, and(2) formaldehyde, the molar ratio of formaldehyde/(phenol or phenol derivatives) being within the range from 5/10 to 8/10.The image-formable resinous composition has a high sensitivity and a high dissolution.

Abstract: X-ray energy-difference images are obtained simultaneously by exposing a body to a broad energy spectrum X-ray beam while a radiographic film package is disposed between front and rear X-ray intensifying screens. The film package has two superimposed films with a light-opaque sheet between them. The front screen, on which the polyenergetic image beam emerging from the body is incident, is excited to luminescence by X-ray photons predominantly in one energy band and the rear screen is excited predominantly by photons in another band. The light opaque sheet preferably contains X-ray filter material for additional filtering of photons to increase the fraction of photons at said other band to which the rear screen is sensitive. A shadowgraph of a marker is formed on the film emulsions during X-ray exposure to aid in matching congruent picture elements on each film when the developed films are being read out to obtain signals corresponding to their intensities.

Abstract: A radiographic image forming process comprising imagewise exposing a negative type silver halide light-sensitive photographic material in combination with a fluorescent intensifying screen to radiation and then treating said material with a processing solution, said material comprising a support and constituent layers coated on both sides of said support, said layers containing(a) light sensitive silver halide particles,(b) metallic salt particles which are not light-sensitive and, when untreated, are more soluble in said processing solution than said silver halide particles, said metallic salt particles having been treated so that the surface thereof has been rendered less soluble than said silver halide by a dissolution retarder,(c) physical development nuclei, and(d) compounds selected from water soluble dyes having absorption maxima in an aqueous solution of from 400 to 600 nm or compounds selected from said water soluble dyes coupled to a non-diffusive mordant, andsaid processing solution containing at l

Abstract: Solid state devices are produced by dry etching of a resist film to produce a negative resist pattern. The film comprises a polymer typically containing a halogen, and at least one type of silicon-containing or nonsilicon-containing organometallic monomer. The radiation, typically X-ray radiation, locks the monomer or monomers into the polymer, with a subsequent fixing step removing the unlocked monomer or monomers in the unirradiated portion of the resist. The film is then exposed to a plasma comprising oxygen, which removes the unirradiated portion at a faster rate than the radiated portion, producing a negative resist pattern. The plasma development is typically accomplished by reactive ion etching. Sensitizers can be used to extend the wavelength response of the films, typically into the ultraviolet or visible regions.

Abstract: Oxyhalides of lanthanum and gadolinium and coactivated with thulium ion and further containing an impurity ion and a second coactivator selected from praseodymium and neodymium, including mixtures thereof, exhibit reduced quantum noise when employed in X-ray image converter devices. In the preferred embodiments, small but effective amounts of ytterbium ion can also be incorporated into the phosphor material to reduce afterglow and a multilayer X-ray screen construction is disclosed employing the improved phosphors.

Abstract: In a radiation image read-out system in which a stimulable phosphor sheet carrying a radiation image stored thereon is exposed to stimulating rays which causes it to emit light in the pattern of the stored image, and the emitted light is photoelectrically read out, the phosphor sheet is uniformly desensitized by the exposure thereof to stimulating rays. Then, preliminary read-out is conducted by use of stimulating rays having stimulation energy lower than the stimulation energy of stimulating rays used in final read-out, and the final read-out conditions and the image processing conditions are set based on the image input information obtained by the preliminary read-out. The desensitization is conducted to eliminate 3% to 60% of the radiation energy stored on the phosphor sheet in order to obtain the image input information suitable for setting the conditions regardless of the interval between the radiation image recording and the preliminary read-out.

Abstract: Photothermographic systems have not been useful in combination with X-ray purposes because of low speed, poor resolution and poor contrast. A particularly designed photothermographic element in combination with a rare-earth intensifying screen provides a high quality, fast, high resolution photothermographic radiographic system.

Abstract: Rare earth oxyhalide phosphors activated with thulium ion are employed in X-ray intensifying screens having modified ultraviolet emission characteristics which reduce crossover effects without significant reduction in film speed and further increases screen brightness. Relatively low concentration levels of the thulium activator ion have been found to shift the ultraviolet emission of said phosphor when excited by X-rays to lower wavelengths in both the ultraviolet and near-ultraviolet spectral regions.

Abstract: Negative working resists, prepared from poly(vinylpyridine) polymers which exhibit good sensitivities to 20 keV electron beam radiation, are disclosed. The poly(vinylpyridine) polymers of this invention may contain alkyl substituents on the pyridine rings in ortho, meta or para positions with respect to the nitrogen atom within said ring.

Abstract: In the patterning process in the fabrication of VLSI, LSI and IC systems, the electron beam is used to write a pattern over a resist layer on a wafer, but the resist layer is exposed by X-rays. More particularly, a finely focused beam of electrons writes a pattern on a thin metal film formed over a resin layer which in turn is formed over a wafer and the secondary X-rays; that is, the characteristics X-rays (such as K.alpha.) emitted from the thin metal film when the electron beam strikes it, expose the resist layer which is sensitive to the X-rays, whereby a high degree of resolution can be obtained.

Abstract: High speed, high quality positive or negative photographic elements comprising, in order, (1) a support, (2) a nonphotosensitive layer on said support containing a chemically bleachable, high strength tinctorial colorant, and (3) at least one photosensitive silver halide emulsion layer, characterized by the interposing of a timing layer between layers (2) and (3), and the addition of a hardener to layer (2).

Abstract: Small amounts of radical traps resorcylaldehyde oxime and 2,2-diphenyl-1-picrylhydrazyl and organic oxidants 2-chloro-5-nitrobenzylchloride, p-nitro-o-chlorobenzyl thiosulfate and 2-(p-nitrobenzyl)thiopyridinium bromide reduce the fog and stabilize the aging of medical X-ray emulsion with little or no effect on speed.

Abstract: A lithographic process utilizing soft x-rays or ions to achieve high resolution is disclosed. The process is particularly useful and semiconductor processing where high resolution is required to achieve a high density. The process utilizes a mask to selectively expose a photoresist to soft x-rays of flood beams of ions. The mask comprises a thin metallic foil supported by a frame such that the foil is in tension. The frame includes optical alignment keys. A second patterned layer of metal is affixed to the foil to form areas which are non-transparent to the soft x-rays or flood ion beams for delineating the elements of a semiconductor circuit, for example. This permits the mask to be optically aligned using conventionally techniques with high resolution being achieved due to the short wavelength of the x-ray radiation or the ion beams.

Abstract: The invention provides a mask structure for X-ray lithography, having a mask substrate of an X-ray transmitting material, a mask pattern of an X-ray absorbing material which is formed on the surface of the mask substrate or therein, a support ring for supporting the rear periphery of the mask substrate, and a lattice-shaped metal film embedded in a lattice-shaped slit in the mask substrate. The mask structure with a large area has a dimensional stability.

Abstract: A silver halide photographic material comprising a base having formed thereon a silver halide emulsion layer substantially made of two or more monodisperse emulsions having different average grain sizes in the range of from 0.2 to 3.0 .mu.m is disclosed. The grain size distribution curve of the silver halide grains in said emulsion layer has two or more peaks, and the distance between the highest peak and the second highest peak is at least 0.3 .mu.m.

Abstract: The invention provides a positive resist comprising a copolymer of 60 to 90 mol % of phenylmethacrylate and 40 to 10 mol % of methacrylic acid.The invention also provides a method for forming a pattern of a positive resist comprising the steps of:forming on a substrate a film of a positive resist which comprises a copolymer of 60 to 90% of phenylmethacrylate and 40 to 10 mol % of methacrylic acid;pre-baking said positive resist film to cross-link said copolymer;selectively radiating said positive resist film which has been pre-baked with a high energy beam to form a latent image; anddeveloping said latent image with a developing solvent. Said positive resist has excellent resistance to dry etching and high sensitivity, and shows good adhesion to a substrate and can realize high resolution.

Abstract: Radiographic elements are disclosed comprised of first and second imaging portions separated by an interposed support capable of transmitting radiation to which the second imaging portion is responsive. At least the first imaging portion includes a silver halide emulsion in which thin tabular silver halide grains of intermediate aspect ratios are present. Spectral sensitizing dye is adsorbed to the surface of the tabular grains. Crossover can be improved in relation to the imaging characteristics.

Abstract: Radiographic elements are disclosed comprised of first and second imaging portions separated by an interposed support capable of transmitting radiation to which the second imaging portion is responsive. At least the first imaging portion includes a silver halide emulsion in which high aspect ratio tabular silver halide grains are present. Spectral sensitizing dye is adsorbed to the surface of the tabular grains. Crossover can be improved in relation to the imaging characteristics.

Abstract: Substituted benzothiazolines are used as antifoggants in high speed silver halide emulsions.

Abstract: Forehardened photographic elements, particularly radiographic elements, intended to produce silver images are disclosed including among hydrophilic colloid layers at least one emulsion layer containing thin tabular silver halide grains. When developed in less than 1 minute to produce a viewable silver image, these photographic elements exhibit increased covering power.

Abstract: An X-ray mask including a pattern of X-ray absorbing material on a thin membrane is provided. The mask includes overlapping first and second patterns of X-ray absorbing material. This permits X-ray lithography printing of lines in complex patterns required for large scale integration. The X-ray mask can provide patterns of less than 20 A in thickness by X-ray irradiation.

Abstract: A structure for shaping or masking energetic radiation is described. The structure comprises a shallow silicon body having at least one through opening, and a metal silicide layer covering the surface of the structure. The structure characterized by having a high mechanical, and thermal stability may be used particularly in electron and X-ray lithography. More specifically, the structure may be used as an aperture for electron beams, or as a mask for X-rays. The production of the structure includes the steps of making through openings in the silicon body, and the forming of the silicide layer by vapor depositing a metal on the surface of the silicon body and by subsequent annealing.

Abstract: Stress and crack-free development of resist layers or films, for example composed of PMMA, used in production of galvanically generated flat precision parts is achieved. Resist layers having a thickness of at least 100 .mu.m are exposed via electron lithography or x-ray lithography techniques whereby very fine structure patterns having dimensions in the micron and sub-micron range are attained and developed with a developer comprised of a mixture of a material selected from the glycol ether group, a material selected from the primary amine group, a material selected from the aqueous group and a material selected from the azine group. Aspect ratios of 30:1 are achieved without dark errosion. Residual PMMA components remaining after development, as well as the developer itself, are fully removed with a post-development rinsing with water so that no disruptive layer residues remain on the surface which has been uncovered through development.

Abstract: A radiation sensitive article formed with large and small grains of silver halide arranged for exposure to radiation and disposed so as to permit development of the large and small grains each under independent development conditions selected to provide image wise development thereof. A method for producing a high resolution high speed photographic image and apparatus for carrying out the method are also provided.

Abstract: A process for forming photographic images comprising a silver image and a dye image, comprising development processing an imagewise exposed silver halide photographic light-sensitive material containing a 4-alkoxy-1-naphthol represented by the formula (I) ##STR1## wherein R represents an alkyl group, an alkoxyalkyl group, or a hydroxyalkyl group, and the number of carbon atoms in the substituent represented by R is from 1 to 4.The process of this invention is particularly useful in the field of X-ray photography, in order to provide an image of increased density for a given silver content. A novel silver halide photographic light-sensitive material includes the above 4-alkoxy-1-naphthol in a photographic colloid layer thereof, preferably the silver halide emulsion layer.

Abstract: A silver-halide/gelatin light-sensitive emulsion containing a saturated cyclic oxime compound, and optionally containing a di- or trimethylol lower alkane compound is disclosed. The light-sensitive emulsion coated on a substrate is particularly useful as a radiographic film.

Abstract: A process for X-ray microlithography useful in the manufacture of microelectronic devices is provided. In the process, a mask in the form of a thin film of a eutectic is interposed between a source of X-rays and a substrate to selectively expose a layer of X-ray sensitive resist situate on the surface of the substrate. After exposure, the resist is developed to yield in the resist a replica of the submicron minimum feature size pattern of the mask.

Abstract: A method of providing a negative electron and/or X-ray resist material on a substrate comprising applying a layer of resist material to the substrate, exposing the layer to a pattern of electrons and/or X-rays and removing the unexposed portions of the layer of resist material in which method the resist material comprises a polyvinylcarbazole compound which (a) contains a polymer and/or a copolymer of the formula ##STR1## in which n exceeds 30 which is halogenated in the nucleus or (b) contains a mixture of the copolymer optionally halogenated in the nucleus with a bisazide of the formulaN.sub.3 RN.sub.3in which R represents an organic residue.

Abstract: A method of depositing X-ray absorber patterns on a mask membrane to achieve minimum pattern feature dimensions less than 1 .mu.m. The membrane is covered with an ultraviolet (VU) sensitive photoresist which carries a thin metallic film. The metallic film is coated with an electron beam resist. The electron beam resist is exposed to the desired pattern by an electron beam. After development, the metal film is etched through the remaining electron beam resist. This forms a stencil overlying the lower UV photoresist layer which is then exposed by an ultraviolet or soft X-ray source. After development, an X-ray absorber, such as gold, is deposited on the membrane. The final exposure step may be done by means of a point source of radiation. The X-ray absorbers will then have sloping walls to prevent shadowing of the X-ray source.