Development of a Magnetic Lens for a Microfocus X-Ray Tube without Forced Liquid Cooling

Introduction. The microfocus X ray tube is a key component in modern medical diagnostic, scientific research, and industrial applications. One of its main elements is the focusing system, with the magnetic lens at its core. The characteristics of this lens largely determine the spatial resolution of the device. Accurate consideration of thermal conditions is essential for ensuring the efficiency and reliability of the focusing system. The importance of thermal analysis has increased significantly due to the tightening requirements imposed on the quality of X ray images. Today, the electron-ic lenses of the X ray tube focusing system are cooled mainly by forced liquid cooling. However, this approach creates additional technological and economic difficulties during the manufacture and operation of the device.
Aim. Construction of a numerical model of thermal processes in a magnetic lens, as well as determination of its optimal parameters for operation without forced liquid cooling and ensuring a micron diameter of the focal spot.
Materials and methods. Numerical and analytical methods were used to construct a model of thermal processes in a magnetic lens. The results obtained were evaluated using numerical modeling of thermal processes implemented in the Comsol Multiphysics environment.
Results. The temperature values of the magnetic lens coil obtained within the calculation model and as a result of simulation did not exceed the maximum permissible values. The temperature distribution graphs across the coil cross section obtained by the calculation and Comsol Multiphysics models showed good agreement, which confirms the validity of the calculations.
Conclusion. The obtained optimal parameters of the magnetic lens ensure its stable operation under natural cooling.

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