Abstract: A microwave plasma reactor for manufacturing synthetic diamond material via chemical vapour deposition includes a microwave generator configured to generate microwaves at a frequency f, a plasma chamber that defines a resonance cavity for supporting a microwave resonance mode, a microwave coupling configuration for feeding microwaves from the microwave generator into the plasma chamber, a gas flow system for feeding process gases into the plasma chamber and removing them therefrom, and a substrate holder disposed in the plasma chamber and having a supporting surface for supporting a substrate on which the synthetic diamond material is to be deposited in use. The resonance cavity is configured to have a height that supports a TM011 resonant mode at the frequency f and is further configured to have a diameter that satisfies the condition that a ratio of the resonance cavity height/the resonance cavity diameter is in the range 0.3 to 1.0.

Abstract: A non-planar body (1) comprising a dome body (2) having an apex (3) and an outer periphery, the apex (3) located on a first plane (4) and the outer periphery located on a second plane (6) substantially parallel to the first plane (4). A peripheral body (5) extends at least partially around the outer periphery of the dome body (2), and at an angle (7) of less than 180° with respect to a tangent (8) relative to the dome body (2) at the outer periphery of the dome body (2), the angle (7) being measured at an outer surface of the dome body (2). Any of the dome body (2) and the peripheral body are formed from polycrystalline diamond.

Abstract: A microwave plasma reactor for manufacturing synthetic diamond material via chemical vapour deposition, the microwave plasma reactor includes a plasma chamber, a substrate holder, a microwave coupling configuration for feeding microwaves into the plasma chamber, and a gas flow system for feeding process gases into the plasma chamber and removing them therefrom. The gas flow system includes a gas inlet array having a plurality of gas inlets for directing the process gases towards the substrate holder. The gas inlet array includes at least six gas inlets disposed in a substantially parallel or divergent orientation relative to a central axis of the plasma chamber.

Abstract: An electrochemical cell for treating a fluid, the electrochemical cell comprising: at least two opposing electrodes defining a flow path for the fluid between the electrodes, where at least one of the electrodes is formed of electrically conductive diamond material; drive circuitry configured to apply a potential across the electrodes such that a current flows between the electrodes when the fluid is flowed through the flow path between the electrodes; and a housing in which the electrodes are disposed, the housing comprising pressure seals configured to containing the fluid within the fluid path and a support structure for supporting the electrodes, wherein the support structure and the pressure seals are configured such that the electrochemical cell has an operating pressure in a range 2 to 10 bar within which the electrodes are supported without fracturing and within which the fluid is contained within the flow path, wherein the electrodes are spaced apart by a distance in a range 0.

Abstract: A microwave plasma reactor for manufacturing synthetic diamond material via chemical vapour deposition, the microwave plasma reactor comprising: a plasma chamber defining a resonant cavity for supporting a primary microwave resonance mode having a primary microwave resonance mode frequency f; a plurality of microwave sources coupled to the plasma chamber for generating and feeding microwaves having a total microwave power P? into the plasma chamber; a gas flow system for feeding process gases into the plasma chamber and removing them therefrom; and a substrate holder disposed in the plasma chamber and comprising a supporting surface for supporting a substrate on which the synthetic diamond material is to be deposited in use, wherein the plurality of microwave sources are configured to couple at least 30% of the total microwave power P? into the plasma chamber in the primary microwave resonance mode frequency f, and wherein at least some of the plurality of microwave sources are solid state microwave sources.

Abstract: A microwave generator system for use in a microwave plasma enhanced chemical vapour deposition (MPECVD) system, the microwave generator system comprising: a microwave generator unit configured to produce microwaves at an operating power output suitable for fabricating synthetic diamond material via a chemical vapour deposition process; a fault detection system configured to detect a fault in the microwave generator unit which results in a reduction in the operating power output or a change in frequency; and a re-start system configured to restart the microwave generator unit in response to a fault being detected and recover the operating power output or frequency in a time period of less than 10 seconds after the fault in the microwave generator unit which caused the reduction in the operating power output or the change in frequency.

Abstract: An earth-boring drilling tool comprises a cutting element. The cutting element comprises a substrate, a diamond table, and at least one sensing element formed from a doped diamond material disposed at least partially within the diamond table. A method for determining an at-bit measurement for an earth-boring drill bit comprises receiving an electrical signal generated within a doped diamond material disposed within a diamond table of a cutting element of the earth-boring drill bit, and correlating the electrical signal with at least one parameter during a drilling operation.

Abstract: A microwave plasma reactor for manufacturing synthetic diamond material via chemical vapour deposition includes a microwave generator configured to generate microwaves at a frequency f, a plasma chamber that defines a resonance cavity for supporting a microwave resonance mode, a microwave coupling configuration for feeding microwaves from the microwave generator into the plasma chamber, a gas flow system for feeding process gases into the plasma chamber and removing them therefrom, and a substrate holder disposed in the plasma chamber and having a supporting surface for supporting a substrate on which the synthetic diamond material is to be deposited in use. The resonance cavity is configured to have a height that supports a TM011 resonant mode at the frequency f and is further configured to have a diameter that satisfies the condition that a ratio of the resonance cavity height/the resonance cavity diameter is in the range 0.3 to 1.0.

Abstract: A method of forming an instrumented cutting element comprises forming a free-standing sintered diamond table having at least one chamber in the free-standing sintered diamond table, providing a doped diamond material within the at least one chamber, and attaching a substrate to the free-standing sintered diamond table to form an instrumented cutting element. The instrumented cutting element includes the doped diamond material disposed within the sintered diamond table on the substrate. A method of forming an earth-boring tool comprises attaching at least one instrumented cutting element to a body of an earth-boring tool. The at least one instrumented cutting element has a diamond table bonded to a substrate. The diamond table has at least one sensing element disposed at least partially within the diamond table. The at least one sensing element comprises a doped diamond material.

Abstract: A polycrystalline chemical vapor deposited (CVD) diamond wafer comprising: a largest linear dimension equal to or greater than 125 mm; a thickness equal to or greater than 200 ?m; and one or both of the following characteristics measured at room temperature (nominally 298 K) over at least a central area of the polycrystalline CVD diamond wafer, said central area being circular, centered on a central point of the polycrystalline CVD diamond wafer, and having a diameter of at least 70% of the largest linear dimension of the polycrystalline CVD diamond wafer: an absorption coefficient ?0.2 cm?1 at 10.6 ?m; and a dielectric loss coefficient at 145 GHz, of tan ??2×10?4.

Abstract: A microwave plasma reactor for manufacturing synthetic diamond material via chemical vapor deposition, the microwave plasma reactor comprising: a microwave generator configured to generate microwaves at a frequency f; a plasma chamber comprising a base, a top plate, and a side wall extending from said base to said top plate defining a resonance cavity for supporting a microwave resonance mode, wherein the resonance cavity has a central rotational axis of symmetry extending from the base to the top plate, and wherein the top plate is mounted across said central rotational axis of symmetry; a microwave coupling configuration for feeding microwaves from the microwave generator into the plasma chamber; a gas flow system for feeding process gases into the plasma chamber and removing them therefrom; and a substrate holder disposed in the plasma chamber and comprising a supporting surface for supporting a substrate on which the synthetic diamond material is to be deposited in use; wherein the resonance cavity is con

Abstract: An electrochemical cell for treating a fluid, the electrochemical cell comprising: at least two opposing electrodes defining a flow path for the fluid between the electrodes, where at least one of the electrodes is formed of electrically conductive diamond material; drive circuitry configured to apply a potential across the electrodes such that a current flows between the electrodes when the fluid is flowed through the flow path between the electrodes; and a housing in which the electrodes are disposed, the housing comprising pressure seals configured to containing the fluid within the fluid path and a support structure for supporting the electrodes, wherein the support structure and the pressure seals are configured such that the electrochemical cell has an operating pressure in a range 2 to 10 bar within which the electrodes are supported without fracturing and within which the fluid is contained within the flow path, wherein the electrodes are spaced apart by a distance in a range 0.

Abstract: An earth-boring drilling tool comprises a cutting element. The cutting element comprises a substrate, a diamond table, and at least one sensing element formed from a doped diamond material disposed at least partially within the diamond table. A method for determining an at-bit measurement for an earth-boring drill bit comprises receiving an electrical signal generated within a doped diamond material disposed within a diamond table of a cutting element of the earth-boring drill bit, and correlating the electrical signal with at least one parameter during a drilling operation.

Abstract: A microwave generator system for use in a microwave plasma enhanced chemical vapour deposition (MPECVD) system, the microwave generator system comprising: a microwave generator unit configured to produce microwaves at an operating power output suitable for fabricating synthetic diamond material via a chemical vapour deposition process; a fault detection system configured to detect a fault in the microwave generator unit which results in a reduction in the operating power output or a change in frequency; and a re-start system configured to restart the microwave generator unit in response to a fault being detected and recover the operating power output or frequency in a time period of less than 10 seconds after the fault in the microwave generator unit which caused the reduction in the operating power output or the change in frequency.

Abstract: An earth-boring drilling tool comprises a cutting element. The cutting element comprises a substrate, a diamond table, and at least one sensing element formed from a doped diamond material disposed at least partially within the diamond table. A method for determining an at-bit measurement for an earth-boring drill bit comprises receiving an electrical signal generated within a doped diamond material disposed within a diamond table of a cutting element of the earth-boring drill bit, and correlating the electrical signal with at least one parameter during a drilling operation.

Abstract: A polycrystalline chemical vapour deposited (CVD) diamond wafer comprising: a largest linear dimension equal to or greater than 125 mm; a thickness equal to or greater than 200 ?m; and one or both of the following characteristics measured at room temperature (nominally 298 K) over at least a central area of the polycrystalline CVD diamond wafer, said central area being circular, centred on a central point of the polycrystalline CVD diamond wafer, and having a diameter of at least 70% of the largest linear dimension of the polycrystalline CVD diamond wafer: an absorption coefficient ?0.2 cm?1 at 10.6 ?m; and a dielectric loss coefficient at 145 GHz, of tan ??2×10?4.

Abstract: A polycrystalline chemical vapor deposited (CVD) diamond wafer comprising: a largest linear dimension equal to or greater than 125 mm; a thickness equal to or greater than 200 ?m; and one or both of the following characteristics measured at room temperature (nominally 298 K) over at least a central area of the polycrystalline CVD diamond wafer, said central area being circular, centered on a central point of the polycrystalline CVD diamond wafer, and having a diameter of at least 70% of the largest linear dimension of the polycrystalline CVD diamond wafer: an absorption coefficient ?0.2 cm?1 at 10.6 ?m; and a dielectric loss coefficient at 145 GHz, of tan ??2×10?4.

Abstract: The present disclosure relates to substrates for use in microwave plasma reactors. Certain substrates include a cylindrical disc of a carbide forming refractory metal having a flat growth surface on which CVD diamond is to be grown and a flat supporting surface opposed to said growth surface. The cylindrical disc may have a diameter of 80 mm or more. The growth surface may have a flatness variation no more than 100 mm The supporting surface may have a flatness variation no more than 100 mm.

Abstract: A polycrystalline chemical vapour deposited (CVD) diamond wafer comprising: a largest linear dimension equal to or greater than 70 mm; a thickness equal to or greater than 1.3 mm; and one or both of the following characteristics measured at room temperature (nominally 298 K) over at least a central area of the polycrystalline CVD diamond wafer, said central area being circular, centred on a central point of the polycrystalline CVD diamond wafer, and having a diameter of at least 70% of the largest linear dimension of the polycrystalline CVD diamond wafer: an absorption coefficient ?0.2 cm?1 at 10.6 ?m; and a dielectric loss coefficient at 145 GHz, of tan ??2×10?4.

Abstract: A method of forming an instrumented cutting element comprises forming a free-standing sintered diamond table having at least one chamber in the free-standing sintered diamond table, providing a doped diamond material within the at least one chamber, and attaching a substrate to the free-standing sintered diamond table to form an instrumented cutting element. The instrumented cutting element includes the doped diamond material disposed within the sintered diamond table on the substrate. A method of forming an earth-boring tool comprises attaching at least one instrumented cutting element to a body of an earth-boring tool. The at least one instrumented cutting element has a diamond table bonded to a substrate. The diamond table has at least one sensing element disposed at least partially within the diamond table. The at least one sensing element comprises a doped diamond material.