CN203057673U - Rotating target of neutron source for fusion reaction high-current accelerator - Google Patents

Abstract

The utility model relates to a rotating target for a fusion reaction high-current accelerator neutron source. The rotating target for the fusion reaction accelerator neutron source changes mechanical interlocking differential motion pumping type vacuum rotating seal on a rotating shaft of an existing rotating target structure into a magnetic fluid sealing device so as to realize high-speed rotation of the rotating shaft and enable a working chamber to keep an operating requirement that the vacuum degree is higher than 10<-3>Pa. The rotating target provided by the utility model adopts the hollow magnetic fluid vacuum sealing rotating shaft with a large diameter, and has the advantages of small rotating resistance, good vacuum sealing performance and long service life. Relevant experiments show that the vacuum degree in a target chamber can be kept at 10<-4>Pa under the condition that the target rotates with a high speed of 1100RPM.

Description

Rotating target of neutron source for fusion reaction high-current accelerator

technical field

The utility model relates to a rotating target used for a neutron source of a fusion reaction strong current accelerator. The utility model comprises: a motor, a synchronous transmission wheel, a synchronous transmission belt, a water tank, a target sheet, a water jacket, a cooling water inlet, a rotating shaft, a vacuum seal, a beam collimator, an inclined flange, a bearing, a water sealing ring and a vacuum sealing O ring.

Background technique

Intensive deuterium-deuterium (DD) and deuterium-tritium (DT) fusion reaction accelerator neutron sources are important single-energy neutron sources, which can be widely used in nuclear data measurement, nuclear fusion reactor basic research, military basic research and other aspects. The basic principle of this accelerator neutron source is to use a high-pressure doubler accelerator to accelerate deuterium (D) ion beams to 400keV energy, and bombard deuterium-titanium (TiD) targets or tritium-titanium (TiT) to generate deuterium-deuterium (DD) and deuterium-tritium (DT) The fusion reaction produces fast neutrons, and the yield of fast neutrons is proportional to the intensity of the D beam that bombards the target. In order to achieve the technical indicators that the fast neutron yield of DD reaction reaches 1-5×10 ¹⁰ s ^-1 and the fast neutron yield of DT reaction reaches 1-5×10 ¹² s ^-1 under the condition of D beam energy of 400keV, the bombardment The intensity of the D beam on the target should reach 10-40mA. Under the requirement of the D beam spot diameter Ф2cm on the target, the maximum power surface density of the D beam within the Ф2cm area of the target is about 5.1kw/ ^cm2 . D beam power density is very high, if no measures are taken, the target will be punctured, and the neutron source of the high-current accelerator will not be able to operate normally. In addition, the neutron source of the fusion reaction high-current accelerator uses a deuterium titanium (TiD) target or a tritium titanium (TiT) gas adsorption target. Technically, it is required to control the temperature of the target surface below 150 ^o C to prevent adsorption in the target titanium film. A large amount of deuterium or tritium is released due to the overheating of the target surface, thereby ensuring the target has a long service life.

The water-cooled large-area high-speed rotating target device can effectively solve the technical problems faced by the high-power-density beam bombardment target in the neutron source of the fusion reaction high-current accelerator. The basic principle is: when the neutron source of the accelerator is running, the large-area target is rotated at high speed, and the high-power-density beam is scanned on the large-area target circular belt, so as to effectively reduce the average power density of the beam per unit area, and at the same time , take water-cooling measures on the back of the target to ensure that the temperature of the target surface caused by beam bombardment does not exceed 150 ^o C. In the water-cooled large-area high-speed rotating target device, the key technology to be solved is the rotating vacuum sealing problem of the high-speed rotating shaft, that is, under the high-speed rotating condition of the rotating shaft rotating at 1100 rpm, the vacuum degree in the target chamber must be kept at 10 ^-4 Pa magnitude. In the previous similar rotating targets, the mechanical occlusal differential pumping vacuum rotary sealing method made of wear-resistant materials is generally used. The vacuum rotary sealing performance is poor, and the dynamic vacuum of rotation can only reach 10 ^-3 Pa. The first disadvantage is the vacuum degree. If it is too low, it will affect the transmission of the beam and the overall performance of the neutron generator. The second is that the service life is short, and the wear-resistant materials need to be replaced frequently.

Contents of the invention

The utility model provides a rotating target for a neutron source of a fusion reaction accelerator which can overcome the disadvantages of the prior art, can ensure high-speed rotation of a rotating shaft, and can keep a working chamber at a vacuum degree higher than 10 ^-3 Pa.

The rotating target of the neutron source of the fusion reaction accelerator of the utility model is based on the existing structure of the rotating target, and the mechanically engaged differential air-pumping vacuum rotating seal on the rotating shaft is replaced by a magnetic fluid sealing device, so as to ensure the high speed of the rotating shaft. While rotating, it can keep the working cavity higher than the requirement of vacuum degree above 10 ^-3 Pa.

The utility model adopts a hollow large-diameter magnetic fluid vacuum seal rotating shaft, and a three-stage magnetic fluid vacuum seal is arranged on the rotating shaft. This technical measure overcomes the vacuum degree of the existing mechanical engagement differential pumping type vacuum rotary sealing rotary target system. Low, short service life and other shortcomings, and has the advantages of small rotation resistance, good vacuum sealing performance, and long service life. Relevant experiments show that the test shows that the vacuum degree in the target chamber can be maintained at 10 ^-4 Pa under the condition that the target is rotated at a high speed of 1100 rpm.

Description of drawings

Accompanying drawing 1 is the structural representation of the utility model.

Accompanying drawing 2 is the enlarged view of A part in accompanying drawing 1.

Accompanying drawing 3 is the enlarged view of B part in accompanying drawing 1.

In the figure: 1-motor; 2-synchronous transmission wheel; 3-synchronous transmission belt; 4-water tank; 5-target piece; 6-water jacket; 7-cooling water inlet; Shaft; 10-magnetic fluid seal; 11-beam collimator; 12-beam axis; 13-rotation axis; 14-inclined flange; 15-bearing; 16-water seal ring; 17-vacuum seal O ring

Detailed ways

The utility model is illustrated in conjunction with the accompanying drawings. Accompanying drawing 1 is the basic structure of a rotating target, wherein: motor 1, synchronous transmission wheel 2 and synchronous transmission belt 3 etc. form target rotating transmission system, its function is to provide rotational power for the magnetic fluid rotating shaft; Rotating shaft 9 is a hollow large diameter The magnetic fluid vacuum-sealed rotating shaft is supported by two bearings and rotates under the drive of the synchronous transmission belt 3. The rotating speed in use is 1100 rpm; Diameter Φ202mm; in order to ensure good heat conduction, the thickness of the target is 1.5mm, and the inner surface of the target is Φ176-Φ116mm on the ring-shaped belt of 5μm thick titanium film, which is used to adsorb tritium (T) or deuterium (D), target 5 It is installed on a barrel-shaped transition flange 8 through a flange and an "O" type vacuum sealing ring 17. The other end of the barrel-shaped transition flange 8 is installed on the rotating shaft 9 through the flange and the "O" type vacuum seal ring, and rotates with the rotating shaft 9 at a speed of 1100 rpm; the water jacket 6, the water tank 4, and the water inlet 7 1. The water outlet (at the bottom of the water tank 4) constitutes the water cooling system of the target piece. The water jacket 6 is stamped from a 1.5mm stainless steel plate. The central area is in the shape of a spherical shell, and the edge area is a flat plate. The water tank is connected as a whole, and the spherical shell in the central area of the water jacket is fitted with the spherical shell of the target piece. A 1.5mm gap is reserved between them as a gap for cooling water flow. When the target piece rotates, the water jacket 6 and the water tank 4 are fixed, 4 kg The pressure cooling enters from the pipe 7 in the central area of the water jacket, and is thrown out from the periphery of the target piece into the water tank 4 through a 1.5mm gap under the joint action of water pressure and the centrifugal force of the target rotation, and then passes through two Φ60mm pipes opened at the bottom of the water tank 4 Natural flow, the water tank is a cuboid made of alloy aluminum material, and its dimensions are: length 360mm × width 100mm × height 400mm.

The rotary vacuum seal is provided by the hollow large-diameter magnetic fluid vacuum seal rotating shafts 9 and 10, and its structural dimensions are: outer diameter Φ264mm, length 166mm; the beam collimation system consists of a water-cooled beam collimator 11 and an inclined flange 14 , the water-cooled beam collimator has two functions: one is to prevent the beam from bombarding the inner surface of the sealed shaft, causing the temperature of the shaft to rise and cause demagnetization; the other is to collimate the high-current D beam to form a Φ20mm beam on the target spot. The function of the inclined flange is: to make the beam axis and the rotation axis form an included angle of 12 ^o , to ensure that the center of the beam is bombarded at a position where the radius from the edge of the circular target is 73mm from the center of the circle. When the target rotates with the axis, the Φ20mm beam spot will Scan on the circular belt in the area of Φ166-Φ126mm on the target piece. The flange of the water-cooled beam collimator system uses a vacuum-sealed "O" ring to connect with the flange of the beam pipe of the neutron generator to maintain a high vacuum in the rotating target chamber.

The above structures are similar to the rotating target of the existing neutron source, but the utility model is different from the prior art in that a three-stage magnetic fluid seal 10 is arranged on the rotating shaft 9 . Its advantages are: small rotation resistance, good vacuum sealing performance, long service life, and at the same time guarantee the normal high-speed rotation of the rotating shaft.

The utility model adopts the hollow large-diameter magnetic fluid vacuum-sealed rotating shaft to realize the high-speed rotating vacuum sealing problem. The actual test shows that when the rotating shaft rotates at 1100 rpm, the vacuum degree of the target chamber can be kept at 1 ×10 ^-4 Pa; Compared with the wear-resistant material occlusal differential pumping vacuum rotary seal, the fluid vacuum seal rotary shaft has a long service life, which can reach 10,000 hours. If the neutron generator operates for 1,000 hours per year, the service life can be up to 10 years.

Claims (2)

1. the rotary target of fusion reaction high-current accelerator neutron source, comprise: motor, synchronous driving wheel, synchronous belt, water tank, target sheet, water jacket, cooling water inlet, rotating shaft, vacuum seal, line collimater, oblique flange, bearing, waterstop ring and vacuum seal O circle is characterized in that rotating shaft vacuum seal is magnet fluid sealing.

2. the rotary target of fusion reaction accelerator neutron generator according to claim 1 is characterized in that rotating shaft is provided with three grades of magnet fluid sealings.

Images