CN204905207U - Powerful fixed anode X -ray tube of little focus - Google Patents

Abstract

The utility model discloses a powerful fixed anode X -ray tube of little focus, including positive pole subassembly, cathode assembly and tube, the positive pole subassembly includes the tungsten target, the negative pole includes filament, characterized by: the target angle of tungsten target is 9 degrees, filament length is 15 degrees 1.6 times of X -ray tube for the target angle, through the aforesaid setting, the general distance one meter human position of the light source of X -ray machine, tan (9) multiply by 1000mm and is equaled 158mm, and radiation field after the upper and lower summation be 316mm, and this radiation field can satisfy the human needs of diagnosing basically, so set up the plate target angle into 9 degrees, does not influence the in -service use after the target angle reduces, filament length is for corresponding 1.6 times of 15 degrees target cornues, is reach by sin15sin9=1.6, and under the unchangeable condition of focus width, actual focal spot's length increases greatly to can improve X -ray tube power.

Description

The powerful fixed anode X-ray tube of little focus

Technical field

The utility model relates to a kind of ray tube, and more particularly, it relates to a kind of X-ray tube.

Background technology

Fixed anode X-ray tube is a kind of diode worked under high voltage condition, comprises two-stage: one is the negative electrode for electron emission, and another is the anode for receiving high energy electron bombardment, and two-stage is sealed in the glass bulb of high vacuum.X-ray tube medically for the diagnosis and treatment of, industrially go up for Non-Destructive Testing and spectrum analysis.

Fixed anode X-ray tube power is in the market smaller, if will increase power must increase focus, and increases Focus Club's effect diagram image sharpness, is unfavorable for diagnosis.Everybody can only find a kind of parameter of compromise for a long time, such as the little C arm of a kind of conventional X-ray machine, and the focal group selected is combined into 0.6 and 1.5, and target angle is 15 degree, and corresponding maximum short-time rating is 1.3KW and 4KW.Above-mentioned focal group is combined into the parameter of X-ray tube, i.e. the combination of the nominal value of focus, and effective focal spot is also called effect focus, refers to that actual focal spot is thrown according to the projection on direction at x-ray.Actual focal spot, in the projection perpendicular to X-ray tube long axis direction, is called nominal focus point.Similar focal group is combined into the identical combination of nominal focal spot value.The nominal value of effective focal spot is a nondimensional numerical value.Above-mentioned target angle is the angulation of target surface and X-ray tube minor axis.

Utility model content

For the deficiency that prior art exists, the purpose of this utility model is to provide a kind of little focus powerful fixed anode X-ray tube.

For achieving the above object, the utility model provides following technical scheme: the powerful fixed anode X-ray tube of a kind of little focus, comprise anode assemblies, cathode assembly and shell, described anode assemblies comprises tungsten target, described negative electrode comprises filament, wherein: the target angle of described tungsten target is 9 degree, 1.6 times of described filament length to be target angle the be filament length of the X-ray tube of 15 degree.

By adopting technique scheme, the position of one meter of the light source general distance human body of X-ray machine, tan(9 °)=0.158 be multiplied by 1000mm and equal 158mm, radiation field after being added up and down is 316mm, this radiation field can meet human diagnosis needs substantially, if target angle is selected too small, radiation field is narrow, the needs of human diagnosis cannot be met, if target angle is excessive, focus must be increased and could increase power, and increase the definition of Focus Club's effect diagram picture, be unfavorable for diagnosis, so plate target angle is set to 9 degree, target angle does not affect actual use after reducing; Filament length is 1.6 times of corresponding 15 degree of target cornue, and drawn by sin15/sin9=1.6, when Focus width is constant, the length of actual focal spot increases greatly, thus can improve X-ray tube power.

The utility model is set to further: described anode assemblies also comprises kovar ring and anode head, and described anode head is welded together by kovar ring and shell.

By adopting technique scheme, kovar ring has the coefficient of linear expansion close to Bohemian glass and corresponding Bohemian glass can carry out effective sealing-in coupling, and good seal performance ensure that the vacuum degree in pipe.

Accompanying drawing explanation

Fig. 1 is the overall structure schematic diagram of the little focus of the utility model powerful fixed anode X-ray tube embodiment;

Fig. 2 is the partial structurtes schematic diagram of the little focus of the utility model powerful fixed anode X-ray tube embodiment.

Accompanying drawing illustrates: 1. anode assemblies; 11. tungsten targets; 12. anode shield covers; 13. kovar rings; 14. anode heads; 2. cathode assembly; 21. filaments; 3. shell.

Embodiment

Referring to figs. 1 through Fig. 2, the little focus of the utility model powerful fixed anode X-ray tube embodiment is described further.

The powerful fixed anode X-ray tube of a kind of little focus, comprise anode assemblies 1, cathode assembly 2 and shell, described anode assemblies 1 comprises tungsten target 11, described negative electrode comprises filament 21, wherein: the target angle of described tungsten target 11 is 9 degree, 1.6 times of described filament 21 length to be target angle the be filament length of the X-ray tube of 15 degree.

Principle of the present utility model is: the computing formula of the maximum power of X-ray tube is as follows:

P=maximum power; The coefficient of K=target; The length of L=focus; The width of W=focus;

The rotating speed of S=target; The diameter of d=focal track; The time of t=exposure; The angle of θ=target;

Show that from above formula can change to find out, the power of X-ray tube be improved, (1) can select resistant to elevated temperatures target, increases the coefficient (K) of target; (2) design large focus (L, W), add length and the width of large focal spot; (3) rotating speed (S) of target is improved; (4) track diameter (d) of focus is increased; (5) time for exposure (t) of X-ray tube is shortened; (6) angle (θ) of target is reduced.

The diameter of focal track is relevant with filament length, and the utility model reduces target angle θ, and adds filament 21 length, is equivalent to the track diameter d increasing focus.

The position of one meter of the light source general distance human body of X-ray machine, tan(9 °)=0.158 be multiplied by 1000mm and equal 158mm, radiation field after being added up and down is 316mm, this radiation field can meet human diagnosis needs substantially, if target angle is selected too small, radiation field is narrow, the needs of human diagnosis cannot be met, if target angle is excessive, focus must be increased and could increase power, and increase the definition of Focus Club's effect diagram picture, be unfavorable for diagnosis, so plate target angle is set to 9 degree, target angle does not affect actual use after reducing; Filament 21 length is 1.6 times of the filament length of corresponding 15 degree of target cornue, and drawn by sin15/sin9=1.6, when Focus width is constant, the length of actual focal spot increases greatly, thus can improve X-ray tube power.

Preferably, anode assemblies 1 also comprises kovar ring 13, anode head 14 and tungsten target 11, described anode head 14 is welded together by kovar ring 13 and shell, by adopting this preferred version: kovar ring 13 has the coefficient of linear expansion close to Bohemian glass and corresponding Bohemian glass can carry out effective sealing-in coupling, good seal performance, ensure that the vacuum degree in pipe.

Preferably, anode assemblies 1 also comprises anode shield cover 12, described anode shield cover 12 is arranged on the outside of kovar ring 13 and shell weld, arranged by this preferred version, anode shield cover 12 effectively stops secondary electron and bombards shell 3 and kovar ring 13 welding position, thus the reliability improved when using continuously, also can not affect the stability of X-ray tube during increasing power.

Preferably, described shell 3 is provided with recessed groove in negative electrode one end, and described cathode assembly 2 also comprises wire filament, has larger wall thickness bottom described recessed groove, and described wire filament is welded on bottom recessed groove.

The advantage of the program is: the setting of recessed groove reduces space in vacuum tube, more easily reaches higher vacuum degree when vacuumizing; The position wall thickness of welding lead is comparatively large, and bonding area is large, and good seal performance, ensure that the sealing in shell 3, thus ensures to have enough vacuum degree in shell 3.

Preferably, the focal group of described fixed anode X-ray tube is combined into 0.6 and 2.0, and maximum short-time rating is 2KW and 6KW.

The above is only preferred implementation of the present utility model, protection range of the present utility model be not only confined to above-described embodiment, and all technical schemes belonged under the utility model thinking all belong to protection range of the present utility model.It should be pointed out that for those skilled in the art, do not departing from the some improvements and modifications under the utility model principle prerequisite, these improvements and modifications also should be considered as protection range of the present utility model.

Claims (2)

1. the powerful fixed anode X-ray tube of little focus, comprise anode assemblies, cathode assembly and shell, described anode assemblies comprises tungsten target, described negative electrode comprises filament, it is characterized in that: the target angle of described tungsten target is 9 degree, 1.6 times of described filament length to be target angle the be filament length of the X-ray tube of 15 degree.

2. the powerful fixed anode X-ray tube of the little focus of one according to claim 1, it is characterized in that: described anode assemblies also comprises kovar ring and anode head, described anode head is welded together by kovar ring and shell.