Miniaturized X-ray tube with cathode and anode made of Koops-GranMat and with retarder

摘要

Miniaturized X-ray tube with a diameter of 5 mm and 20 mm in length, which has at least one cold field emission cathode and an anode, both made of Koops-GranMat® and installed in a vacuum space pumped by a miniaturized Orbitron pump. The high voltage for the emitter, the Orbitron pump and the anode voltage are generated in the miniaturized X-ray tube system and embedded in solid state insulation. The power supply of the tube has a flexible low voltage cable. The X-radiation is generated with electrons from a cold field emission cathode made from Koops-GranMat® (Pt / C). They are pulled out with a first high-voltage saddle point that acts as an ion mirror potential and are further accelerated with several high-voltage double electrodes with ion mirror potential and finally focused on the Koops-GranMat® (Pt / C or Au / C) anode, and the electrons excite characteristic X-rays of the L, M, and N lines in the anode. Electrons leaving the anode after X-ray generation by elastic and inelastic scattering are delayed by negative-potential delay gratings before hitting the inner wall of the X-ray tube, thereby reducing the heating of the wall by the scattering of the scattered electrons Body and tissue can be used for X-ray therapy. The use of Koops-GranMat® as the cathode and anode material allows the use of much higher source currents and the use of much higher current density for X-ray generation at the anode. The supply current is supplied as a low voltage from the outside, and the high voltage required for the pump and the X-radiation is generated in the tube by means of a miniaturized cascade amplifier, all of which are embedded in solid state insulation. A multi-stage accelerator is used to deliver high-voltage accelerated electrons as required for X-ray imaging, X-ray phase-contrast imaging, and the timely medical treatment of tissue with X-radiation. Characteristic of the X-ray tube as well as other standard brachytherapy X-ray sources is that the radiation emission can be switched on and off. The advantage over all other X-ray sources and tubes is the use of the cold field emission source, which has a much higher brightness and a much higher emission current and that in the acceleration region an ion mirror optics in the area of the cathode and anode is used to control the ion impact on the field emission Cathode, and by using an anode material that can not be heated by the electron impact since the photon spectrum in the Koops-GranMat® anode material is geometrically quantized by the size of the crystals to 2 meV or 23K.