Recommend our new product - Carbon Nano Cold Cathode X-ray Tube
Our cold cathode X-ray tube uses carbon nanostructures as the cathode electron source, a fixed anode, and a metal ceramic shell. Cold cathode field emission does not require time to heat the filament or rotate the anode, and can be turned on and off as needed, operating at room temperature. Compared to traditional hot cathode ray tubes, it is smaller, lighter, more compact in design.
X-ray tube is a vacuum electronic device that uses high-speed electrons to collide with a metal anode target to generate X-rays. It mainly consists of two basic parts: cathode and anode. The working mode of the cathode determines the design of multiple aspects such as electron emission control, focusing, beam limiting, acceleration, and anode target surface inside the X-ray tube, thereby affecting the final performance of the X-ray tube. Cathode materials have two common working modes: hot electron emission and cold field emission.
Hot cathode electron emission
As the name suggests, thermionic emission is the process of externally heating a material, causing the kinetic energy of electrons inside the material to continuously increase. When the energy exceeds the surface potential barrier that needs to be overcome, electrons will detach from the surface of the material. The most typical material for thermionic emission is tungsten filament. When tungsten filament is heated to 2000℃, emitting a large number of electrons, so there is a preheating process for thermionic emission.Traditional X-ray tubes use hot cathode tungsten wire as the electron source, which has problems such as high energy consumption, slow response, short lifespan, and difficulty in miniaturization.
Cold cathode electron emission
Cold cathode refers to a cathode that utilizes the principle of field emission. Compared to a hot cathode, its electron emission process does not require heating. By applying an external electric field to suppress the potential barrier on the surface of an object, the height and width of the potential barrier are reduced. When the width of the potential barrier is narrow enough to be comparable to the wavelength of electrons, electrons inside the object will escape from the surface of the object and be emitted into the vacuum through tunneling effect, which is what we call field emission. Field emission instantly emits electrons by applying an electric field, which has the characteristics of fast time response and low power consumption, and has the potential to overcome the problems of traditional hot cathode X-ray tubes.
Carbon nanotube (CNT) cold cathode
Carbon nanotubes (CNTs) are one-dimensional nanomaterials with small sizes and large aspect ratios, which exhibit significant field enhancement effects and can serve as efficient sources of field emission electrons. Due to the geometric enhancement effect, carbon nanotubes are more likely to obtain large field emission currents at low voltages than metals. Carbon nanotubes are highly suitable as cathode materials for X-ray tubes due to their excellent field emission performance. The use of carbon nanotubes as cold cathodes in X-ray tubes has great potential to replace traditional hot cathode X-ray tubes and develop towards a more intelligent direction.
Our cold cathode X-ray tube uses carbon nanostructures as the cathode electron source, a fixed anode, and a metal ceramic shell. Cold cathode field emission does not require time to heat the filament or rotate the anode, and can be turned on and off as needed, operating at room temperature. Compared to traditional hot cathode ray tubes, it is smaller, lighter, more compact in design, more energy-efficient, and reduces the need for large, heavy-duty generators or battery packs.
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