DE2008783B2 - Method for assembling an X-ray tube - Google Patents

Description

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direction of the anode on the cathode depends essentially on the eye of the glassblower. It is understandable that a more precise alignment with this Procedure is not possible This is particularly the case with omnidirectional X-ray tubes with a conical anode, where the electron beam hits the tip of the anode cone, a serious disadvantage, because then the X-ray yield is not the same in all directions around the cone.

The invention is based on the object Verfahrrji for assembling an X-ray tube of the type mentioned at the outset to indicate an exact alignment between anode and cathode enables the X-ray tube to be tempered after the glass has been attached and the interior of the tube to be cleared oxide layers and other impurities and the penetration of dust and the like largely prevented when the tube is closed. According to the invention, this task is thereby achieved solved that first the rings are glazed on both sides of the glass bulb and that then the cathode and the anode are welded to one of the rings.

The invention is explained below using an exemplary embodiment shown in the drawing, which is a view of an X-ray tube manufactured by the method according to the invention.

The drawing shows an X-ray tube with a glass bulb 1, a cathode 2 and an anode 3. The anode 3 is welded to a ring that is glazed onto the glass bulb 1. So is the cathode! or the metal disk 7 welded to the cathode cylinder 6 made of metal a ring 4 welded, which is glazed to the glass bulb I.

The assembly of this tube goes roughly as follows: The two rings 4 and 5 are in the coaxially running chuck is clamped in a suitable device and glazed onto the glass bulb 1. The glass tensions that arise during glazing are then eliminated by tempering. Tempering results in temperatures that lead to oxidation or tarnishing of rings 4 and 5 to lead. The oxide layers and any other impurities can, however, be better known Chemically or mechanically (sandblast cleaning). Then the glazes can be examined for any leaks so that even at this stage a possibly leaky Glazing can be improved Vann.

The anode 3 or the cathode 2 is then welded to the rings 5 or 4. For these purposes, what is known as the »argon arc welding process is particularly suitable known procedures. The arc or the welding point is flushed with argon. Except argon other protective gases that prevent oxidation can also be used. With these procedures almost point-like welds can be achieved, so that the heating of the rings or the anode or the cathode close to the weld is very small. That is essential because otherwise the sequence of the steps of the known process could - first connect ring and anode, then glaze on - not be reversed. The temperature of these areas can be adjusted with a suitable Keep the arc current setting below 100 degrees. An advantage of this procedure is that it can be carried out in a so-called "white room", i.e. one with air locks and the like provided, almost dust-free space. First the anode is placed in a lathe chuck clamped, the glass bulb or the glass-enclosed ring 5 is slipped over the anode and placed on an approach 8 on the anode 3, the ring 9 brazed to one of the copper anode, the consists of the same material as the rings 4 and 5, is provided. The ring 9 is for welding required because a direct welding of the solid copper anode 3 with the ring S because of the different melting points and the good thermal conductivity of the anode are difficult to achieve is. At the same time, the disk welded to the cathode cylinder 6? into a recess in the Ring 4 inserted. During the welding of the anode, it is fastened in the disk 7 via the Pump nozzle 10 flushed the inside of the flask with nitrogen. This rinsing also takes place during the subsequent one Welding of the disk 7 to the ring 4.

The rings 4, 5 and 9 and the disk 7 are preferably turned parts which are adapted to one another with close tolerances. This results in a very precise alignment of the cathode with the anode, so that only minor deviations are possible even during production. These deviations are sufficient in most applications. In the case of omnidirectional X-ray tubes with a conical anode, however, these small deviations (less than ¹ ZiO millimeter) are still disturbing because the intensity of the X-ray radiation is no longer the same in the various directions. In order to achieve an exact adjustment in these cases, the cathode cylinder 6 can be bent with respect to the disk 7 if necessary.

1 sheet of drawings

Claims (4)

th with the silver solder in a wide range around the patent claims: Solder point strongly heated, so that there is a risk that gas residues are bound to the heated points. 1. Method of assembling an X-ray In addition, it is not apparent how doing this cathode genröhre whose glass bulbs are precisely aligned with one another on a ring made of 5 and anode an alloy with approximately the same can. It is true that the metal rings that have the Ka coefficient of thermal expansion as the glass method or anode structure wear, is easily glazed, in turn, each with one of the exactly aligned when their Electrodes are welded, thereby indicating dimensions on the cylindrical metal piston, that at first the rings (4, io are fitted. Since, however, the anode and the cathode 5) on both sides of the glass bulb are not directly connected to the metal rings - and that afterwards the cathode (2) and what is not even possible for reasons of insulation The anode (3) is connected to one of the rings (4, S) - but via glass rings, it is very practical be welded. difficult to pinpoint the anode and cathode exactly 2. The method according to claim 1, thereby aligning 15 metal rings and thus to one another,
indicates that after the glazing and before it is furthermore from the USA patent specification the welding of the glass bulbs is annealed 2 640167 an X-ray tube with a glass bulb. known, at the anode and cathode from there- 3. Method according to one of the preceding soldered or welded metal rings Claims, characterized in that the 20 are worn, the expansion coefficient of which corresponds to X-ray tube chemically corresponds to the glass before welding. These metal rings are on each or mechanically cleaned. one end of a glass collar, the other 4. The method according to claim 3, characterized in that the end is glazed onto the glass bulb. Although in indicates that prior to the welding of this publication no information about the rei anode (3) with the ring (5) a ring (9) to the sequence of the individual connections at the joint anode is soldered, which are then included with the ring (5) menbau of the X-ray tube, must be welded on will. nomm-jn will be that as the last procedural step During assembly, the glass collar is attached to the glass bulb, as the other connecting 30 represent the items are practically no longer accessible at the end of the assembly process. Because the final closure of the vacuum vessel The invention relates to a method for assembling in the known method in glass blowing an X-ray tube, the glass tube of which follows, it cannot be avoided that contamination get into the tube on a ring made of an alloy with approximations (dust or the like), with the same coefficient of thermal expansion. In addition, in most cases the ring will oxidize how the glass is glazed, which in turn is part of the glazing. If the one of the electrodes is welded. X-ray tube atoms out of this oxide layer - An X-ray tube with a ring loosened from its glass bulb occurs - especially with high made of an alloy is glazed, the same 40 voltages - to disturbances (breakdowns) in the Has thermal expansion coefficients such as glass, X-ray tubes. and in which the ring can either be soldered or welded to the anode is from the USA. The ring, which is left behind in the glass bulb or in the ring, compensates for the different thermal conditions. cannot be completely eliminated. A »Temsche expansion coefficient of the glass bulb pern«, ie a repeated heating of the glass and copper anode-related mechanical chip-metal connection until the glass softens, is hardly intended, but iron-nickel can be used because the glass bulb while evacuated there are kel-cobalt alloy. Must be about the connection. so that the external air pressure would compress the glass of the cathode with the glass bulb as well as via the closed bulb,
The assembly of the X-ray tube is a major disadvantage of the known method. Publication does not contain any information. rens lies in the fact that the anode and the It is furthermore from the USA patent specification that cathodes cannot be precisely aligned with one another 2,332,426 an X-ray tube with a metal piston. The reason for this lies not only in the well-known. The anode and the cathode are used on 55 common pinch foot construction, through the one end of each one »for electrical insulation, so that the supply lines to the cathode are led across the glass ring required for the metal bulb also in the fact that anode and cathode never have the same glass, at the other end of which a metal ring can be clamped and glazed at an early stage because is glazed. The metal ring is connected to a flange while the inside of the piston is attached with a stick, which must be filled by means of a silver solder on the metal 60 so that tarnishing of the piston is soldered, the soldering is prevented as the last anode or cathode components. Assembly step is done. During the annealing of the cathode, the X-ray tubes with metal bulbs, however, have glass bulbs at their anode-side end Compared to X-ray tubes with glass bulbs, basically a stopper is closed and one on the lent the disadvantage that nitrogen was released from the metal surface of the cathode side pump nozzle Gas residues supplied to the piston as a result of the heating during operation. Then the stopper is pulled out can break out, which the vacuum in the tube and the anode are glazed, being again through the worsen. Furthermore, the metal is supplied with nitrogen when the Lo pump nozzle is used. The alignment