High-precision second neutron beam line switch and collimation installation method for multi-station switching

Abstract

The present invention discloses a high-precision second neutron beam line switch for multi-station switching and a collimation installation method. The switch is started by a control system, and a lead screw drives a workbench to move to realize sequential position switching of three stations of a guide tube, a collimator and a beam stopper main component. The present invention adopts motor drive, encoder feedback control, and limit switch for auxiliary control, and the terminal position is fed back and positioned by an encoder system. Compared with the prior art, the technical solution of the invention has the advantages of simple operation, short movement time, high repeated positioning accuracy, and the ability to quickly and conveniently realize station switching and beam on and off. It can cut off the neutron beam at the third station. The rear end of the second neutron beam line switch belongs to a radiation safety area, and personnel can enter the rear end area of ​​the second neutron beam line to perform equipment maintenance and sample replacement operations.

Description

Technical Field

[0001] The present invention relates to the technical field of neutron beam line switches, and in particular to a high-precision second neutron beam line switch with multi-station switching and a collimation installation method. Background Art

[0002] Neutron spectrometers are mainly used to study the structure and properties of various substances. Currently, there are two main types of neutron spectrometers built around the world. The first type is called a neutron spallation source spectrometer. The neutron spallation source is based on an accelerator accelerating protons to bombard a target to produce neutrons. The second type is called a neutron reactor spectrometer. The neutron reactor is based on uranium fission to produce neutrons.

[0003] The neutron beam line switch is used to open and cut off the neutron beam in the neutron spectrometer. When in the on state, the neutron beam is transmitted to the sample through neutron optical components such as neutron guide tubes. For neutron spallation source spectrometers, each spectrometer needs to be equipped with a beam line switch in the spallation target station, also known as the main beam line switch. Since the main switch in the target station is relatively large in size and the opening and closing time is relatively long, some neutron spallation source spectrometers will build a second neutron beam line switch on the neutron beam line in the spectrometer hall, such as the magnetic reflection spectrometer BL4A and liquid reflection spectrometer BL4B of the Neutron Spallation Source (SNS) in the United States. The second neutron beam line switch is generally set to be relatively light and easy to control, so that the operation time is short. In addition, since the second neutron beam line switch is located on the neutron beam transmission line, the design accuracy needs to be high.

[0004] Based on experimental requirements, some spectrometers need to build a device that can realize the switching of three or more components on the beam transmission path, such as position switching of two catheters of different specifications and one collimator, or position switching of three catheters of different specifications and sizes. When the beam flow interruption function of the second neutron beam line switch and beam transmission components of different specifications are integrated together, it is necessary to build a second neutron beam line switch with a multi-position switching function. When the equipment is working normally, it is necessary not only to ensure the transmission of neutron beams by neutron transmission components of different specifications through component switching, thereby ensuring the neutron flux at the sample position, but also to reliably cut off the neutron beam when personnel enter the heat dissipation room to ensure personnel safety.

[0005] In addition, the repeatability of the positioning accuracy of the neutron guide tube or collimator in the second neutron beam line switch in the on state needs to be the same as that of the neutron guide tube, while the alignment installation accuracy of the neutron guide tube or collimator is relatively high and needs to reach 0.05 mm. The neutron beam line switch in the prior art is mainly driven by hydraulic or pneumatic pressure, and is switched on or off by moving up and down. For example, the Chinese patent (publication number CN104134471A) discloses a neutron channel gate device, which drives the neutron channel up and down by a cylinder, and uses a limit switch for signal feedback to realize the opening or closing of the neutron channel. However, due to the use of pneumatic drive and signal feedback by the limit switch, the repeated positioning accuracy when the neutron channel is opened is low; and the Chinese patent (publication number CN103454293A) discloses a neutron beam line switch and an alignment installation method, which realizes the alignment installation of the beam line switch by step-by-step matching of a concave platform and a convex platform. The technical solution also discloses a vacuum sealing method using a sealing ring and a flange, which can realize a vacuum shell system for neutron conduction, but it is limited to realizing a vacuum shell system and an alignment installation method, and it is difficult to ensure the repeated positioning accuracy of the neutron guide tube in the neutron beam line switch, and it is also difficult to ensure the high-precision requirements of the neutron beam. Summary of the invention

[0006] The main purpose of the present invention is to address the technical problems in the prior art of low positioning and repeated positioning accuracy of neutron beam line switches and the inability to achieve multi-station switching, and to propose a high-precision second neutron beam line switch with multi-station switching and a collimation installation method, aiming to design a second neutron beam line switch on the spectrometer beam line that is easy to operate, has short movement time, high repeated positioning accuracy, and has multi-station switching function and beam flow control function.

[0007] To achieve the above-mentioned purpose, the present invention proposes a high-precision second neutron beam line switch with multi-station switching, including a shielding support system arranged on the periphery, a switch movement system arranged inside the shielding support system, and a beam shielding system connected to both the shielding support system and the switch movement system to achieve beam shielding.

[0008] The shielding support system includes a base with an embedded steel plate inside, the front and rear sides of the top of the base are respectively connected to a front shielding support plate and a rear shielding support plate, the top surface of the base is fixedly connected to a right bottom plate and a left bottom plate, the tops of the front shielding support plate and the rear shielding support plate are fixedly connected to the top support plate at the same time, the top surface of the top support plate is fixedly connected to the left top plate and the right top plate, shielding filling blocks are respectively provided between the front shielding support plate and the rear shielding support plate and the top support plate, the top support block, the front shielding support plate, the rear shielding support plate and the base together constitute an internal hollow frame structure and accommodate the switch motion system, the surfaces of the front shielding support plate and the rear shielding support plate are provided with through holes that can be axially opposite to the central channel of the catheter or the collimator and coincide with the beam center.

[0009] The beam shielding system includes an upper beam stopper assembly connected to a top support plate, a main beam stopper assembly connected to a switch motion system, and a lower beam stopper assembly connected to a base. When the second neutron beam line switch is in the third position, the main beam stopper assembly of the beam shielding system can be located on the center line of the beam and play a shielding role. The main beam stopper assembly realizes switching of different working modes through horizontal movement.

[0010] The switch motion system includes a power transmission system, a control system, a base and a support system, a guide tube and an adjustment system, and a collimator and an adjustment system.

[0011] Preferably, the power transmission system includes a motor installed on the top surface of the base plate, the power output end of the motor is connected to the screw rod through a coupling, the two ends of the screw rod are respectively installed and positioned by support assemblies, the screw rod is rollingly connected to the ball nut, the ball nut is fixedly connected to the workbench, the motor drives the screw rod to rotate and the ball nut drives the workbench to move linearly.

[0012] Preferably, the control system includes a coding system and a mechanical limit switch. The coding system includes a grating scale arranged on the side of the base plate and a reading head installed on the surface of the workbench. The reading head realizes positioning and feedback by scanning the scale on the surface of the grating scale. The coding system uses an absolute encoder to record the stroke position and save data; the mechanical limit switch is installed on the surface of the base plate and cooperates with the trigger block installed at the bottom of the workbench to realize stroke control.

[0013] Preferably, the base and support system include a bottom plate, a bottom plate connecting plate, a guide rail and a slider arranged at the bottom. The bottom surface of the bottom plate is fixed to the top surfaces of the right bottom plate and the left bottom plate through the bottom plate connecting plate. Two parallel guide rails are symmetrically installed on the surface of the bottom plate. The guide rails are slidably connected to the slider. The slider is connected to the bottom surface of the workbench and cooperates with the screw rod and the ball nut to slide.

[0014] Preferably, the catheter and adjustment system include a catheter, an adjustment system and a catheter connecting plate, the catheter is movably arranged at the center of the beam, the adjustment system is arranged at the bottom of both ends of the catheter and adjusts the spatial position of the catheter, and the adjustment system is connected to the workbench through the catheter connecting plate; the collimator and adjustment system include a collimator and an adjustment system, the collimator can be moved to the center line of the beam and the installation position of the collimator can be adjusted by two adjustment systems at the bottom of both ends; the beam stopper main component is fixed on the top surface of the workbench and switches between three working states with the workbench, the surface of the beam stopper main component is provided with an elevation target seat and a horizontal target seat for alignment measurement, the surfaces of the catheter and the collimator are respectively provided with target seats, and alignment calibration can be performed using a measuring arm and position detection and alignment installation can be performed using a laser tracker.

[0015] Preferably, the beam stopper main component, the beam stopper upper component and the beam stopper lower component are respectively formed by stacking and connecting different material layers in sequence.

[0016] Preferably, the adjustment system includes an adjustment mechanism base plate, a horizontal movement plate and an elevation adjustment plate installed from bottom to top, wherein the adjustment mechanism base plate is fixedly mounted on the base, and the horizontal movement plate is mounted on the adjustment mechanism base plate. The horizontal movement plate is in the shape of a rectangular block, wherein horizontal adjustment components are mounted on three sides thereof, and there are six horizontal adjustment components, wherein each of the two corresponding sides parallel to the beam direction has two horizontal adjustment components, and the horizontal adjustment components on the two sides are axially symmetrically designed, and two are mounted on the sides close to the outside of the two corresponding sides perpendicular to the beam direction, and no horizontal adjustment components are mounted on the sides close to the inside.

[0017] Preferably, the high-precision second neutron beam line switch can realize three-position switching. In the first position, the guide tube is located on the beam center line, and the guide tube plays the role of transmitting the neutron beam; in the second position, the collimator is located on the beam center line, and the collimator plays the role of transmitting the neutron beam; in the third position, the beam stopper main assembly is located on the beam center line and plays the role of cutting off the neutron beam.

[0018] The present invention also discloses a method for collimating and installing a high-precision second neutron beam line switch using the multi-station switching, comprising the following steps:

[0019] Step S1: Calibration, by establishing the relative position relationship between the target component and the target seat in three-dimensional space, adjusting the position of the target component by adjusting the target seat, and calibrating the catheter and the collimator tube respectively.

[0020] First, the catheter is calibrated: the catheter is placed on an optical platform, the inner side and the front and rear end surfaces of the catheter are measured using a measuring arm, and then the catheter target seat on the outer surface of the catheter is measured to establish the spatial position relationship between the inner dimensions of the catheter and the catheter target seat, and obtain the theoretical position coordinates of the catheter target seat in space.

[0021] Then the collimator is calibrated: the collimator is placed on the optical platform, the inner side and front and rear end faces of the collimator are measured using the measuring arm, and then the collimator target seat on the outer surface of the collimator is measured to establish the spatial position relationship between the inner size of the collimator and the collimator target seat, and obtain the theoretical position coordinates of the collimator target seat in space.

[0022] Regarding the calibration of the beam stopper main assembly: Since the positioning accuracy of the beam stopper main assembly and the base plate connecting plate is relatively low, all processing and installation errors are ignored and no calibration is required. Only the drawing dimensions are used to obtain the theoretical position coordinates of the target seat in space. The actual size of the beam stopper main assembly is larger than the theoretical calculated size. The beam stopper main assembly is directly assembled and positioned based on the rough positioning of the base plate connecting plate.

[0023] Step S2: Install the base connecting plate of the base: First, use a laser tracker to align and lay out the lines. Use the laser tracker to set eight points on the ground. The points in the horizontal and vertical directions are connected in pairs. Four straight lines intersect to form a rectangular frame. The length and width of the rectangular frame are equal to the length and width of the base.

[0024] Then install the base with the embedded steel plate on the top on the ground, and the four side lines of the bottom of the base coincide with the four straight lines on the ground. Then install and fix the left base plate, the right base plate, and the lower assembly of the beam stopper on the base. Then install the base plate connecting plate on the left base plate, the right base plate, and the lower assembly of the beam stopper that have been installed in place. There is no need to tighten the fixing screws in advance during the installation process. Install the eight sets of auxiliary adjustment mechanisms on the right base plate and the left base plate respectively.

[0025] The target seat with pin is installed on the base plate connecting plate through the positioning pin hole and screws. The position coordinates of the target seat are detected by laser tracker, and eight sets of auxiliary adjustment mechanisms are adjusted. The elevation direction is adjusted by adding or reducing gaskets. When the coordinate measurement value of the target seat and the theoretical coordinate deviation are less than 3mm, the base plate connecting plate has been installed to the theoretical position. Then remove the target seat and the auxiliary adjustment mechanism, and finally tighten the fixing screws.

[0026] Step S3: Install the switch motion system: assemble the power transmission system, control system, base and support system, and then install the whole system on the bottom plate connecting plate, position it with the positioning pins and lock it with bolts;

[0027] Then, the beam stopper main component connecting plate is installed on the workbench through the locating pins, and the beam stopper main component is installed on the beam stopper main component connecting plate, and the elevation target seat on the beam stopper main component is measured by a laser tracker. When the error between the measured value and the theoretical value of the elevation target seat in the elevation direction and along the beam direction is less than 5mm, the beam stopper main component has been installed in place in the elevation direction and along the beam direction. Since the installation error of the base plate connecting plate is 3mm, and all the components on the base plate connecting plate are bolted after positioning by locating pins, the accuracy loss is very small, and the error requirement of the elevation target seat on the beam stopper main component in the elevation direction and along the beam line direction is less than 5mm, so no adjustment process is required, and the beam stopper main component can be aligned and installed in place in these two directions; in this process, the value of the elevation target seat perpendicular to the beam direction does not need to be adjusted, and then the catheter connecting plate, the adjustment mechanism at the bottom of the catheter and the catheter are installed on the workbench, and the collimation tube and the adjustment mechanism at the bottom are installed on the workbench.

[0028] Step S4: Collimation installation and debugging:

[0029] First, the motor and encoder system are powered on, and the motor drives the workbench to move horizontally. The laser tracker is used to detect the horizontal target seat on the beam stopper main assembly. Since the encoder system is used for control feedback and the ball screw system is used for transmission, the horizontal movement step value of the workbench is much smaller than the collimation installation accuracy. When the deviation between the measured value and the theoretical value of the horizontal target seat perpendicular to the beam direction is less than 1mm, the motor stops rotating and the encoder records the current position, that is, the beam main stopper assembly has been installed to the theoretical position in the three-dimensional direction.

[0030] Then the motor rotates again, and the workbench moves horizontally for a theoretical length of L1. At this time, the center of the catheter is near the center of the beam. The laser tracker is used to detect the target seat on the catheter and adjust the two sets of adjustment systems at the bottom. During the adjustment process, if the measured value and theoretical value of the target seat deviate greatly, the workbench can also be moved for adjustment. When the coordinate measurement value of the target seat and the calibrated theoretical coordinate deviation are less than 0.05mm, the encoder records the current position, that is, the catheter is installed to the theoretical position.

[0031] Then the motor rotates to make the workbench move horizontally by the theoretical length L2. At this time, the center of the collimator is located near the beam center. The laser tracker is used to detect the target seat on the collimator and adjust the two sets of adjustment systems at the bottom. During the adjustment process, if the measured value and theoretical value of the target seat have a large deviation, the workbench is moved for adjustment. When the deviation between the coordinate measurement value of the target seat and the calibrated theoretical coordinate is less than 0.05mm, the encoder records the current position and the collimator is installed at the theoretical position. At this point, the collimation installation is completed.

[0032] Step S5: Finally, install the front shielding support plate, the rear shielding support plate, the top support plate, the left top plate, the beam stopper upper assembly, and the right top plate, thereby completing the installation of the entire multi-station switching high-precision second neutron beam line switch.

[0033] The technical solution of the present invention has the following advantages over the prior art: the technical solution of the present invention adopts a motor for driving and an encoder system for position feedback, thereby achieving high-precision positioning, and sliding friction contact is adopted between the slider and the guide rail, so that the friction coefficient between the two is low, and high load can be achieved, and an absolute encoder is also used to record the position after the collimation installation, so as to ensure high positioning accuracy and no data loss. At the same time, the position switching of the catheter, the beam stopper main assembly and the collimation tube can be realized in turn to meet different working conditions and experimental requirements; in summary, the technical solution of the present invention has the advantages of simple operation, short movement time, high repeated positioning accuracy, and the ability to quickly and conveniently realize workstation switching and beam on and off. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0035] Figure 1 A schematic diagram of the three-dimensional structure of the high-precision second neutron beam line switch for multi-station switching of the present invention;

[0036] Figure 2 It is a schematic diagram of the three-dimensional structure of the shielding support system of the present invention;

[0037] Figure 3 A top view of the shielding support system of the present invention;

[0038] Figure 4 for Figure 3 Sectional view in the AA direction;

[0039] Figure 5 A top view of the switch motion system of the present invention;

[0040] Figure 6 for Figure 5 Sectional view in the AA direction;

[0041] Figure 7 It is a front view of the switch motion system of the present invention;

[0042] Figure 8 It is a rear view of the switch motion system of the present invention;

[0043] Fig. 9 It is a three-dimensional structural schematic diagram of the adjustment mechanism of the present invention;

[0044] Fig.10 It is a three-dimensional structural schematic diagram of the auxiliary adjustment mechanism of the present invention;

[0045] Fig.11 It is a schematic diagram of the three-dimensional structure of the bottom plate connecting plate of the present invention;

[0046] Fig.12 It is a schematic diagram of the three-dimensional structure of the beam stopper main component of the present invention.

[0047] Description of Figure Numbers:

[0048] Label name Label name 1 Switching motion system 25 Adjustment mechanism connecting plate 2 Shielding support system 26 Ball Nut 3 abutment 27 Sports Table 4 Rear shield support plate 28 Conduit connection plate 5 Shielding filler blocks 29 slider 6 Top support plate 30 Adjustment mechanism base plate 7 Left top plate 31 Level adjustment components 8 Beam stopper upper assembly 32 Elevation adjustment components 9 Right top plate 33 Level adjustment screw 10 Front shield support plate 34 Horizontal sports board 101 Rectangular hole 35 Elevation adjustment plate 11 Beam stopper lower assembly 36 Locking screw 12 Right bottom plate 37 Reading head 13 Left bottom plate 38 Linear ruler 14 guide 39 Auxiliary adjustment plate 15 Lead Screw 40 Auxiliary adjusting screw 16 catheter 41 Fixing screw 17 Beam stopper main assembly 42 Auxiliary adjustment mechanism 18 Collimator 43 Fixing screw 19 Support components 44 Beam stopper main assembly connecting plate 20 Couplings 45 Horizontal target mount 21 Motor 46 Elevation target mount 22 Bottom plate connecting plate 47 Boron Carbide Block 23 Base Plate 48 Lead weight 24 Adjustment mechanism 49 Carbon steel shielding block 50 Workbench 51 Horizontal fixing block 52 Tie rod assembly 53 Push rod assembly 54 Ladder Block

[0049] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0050] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back...), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0052] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0053] The invention provides a high-precision second neutron beam line switch with multi-station switching.

[0054] The high-precision second neutron beam line switch with multi-station switching in this embodiment can realize three-station switching, wherein at the first station, the guide tube 16 is located on the beam centerline, and at this time the guide tube 16 plays the role of transmitting the neutron beam; at the second station, the collimator 18 is located on the beam centerline, and at this time the collimator 18 plays the role of transmitting the neutron beam; at the third station, the beam stopper main assembly is located on the beam centerline, and plays the role of cutting off the neutron beam. Under the working condition of the third station, the rear end of the second neutron beam line switch belongs to the radiation safety area, and personnel can enter the rear end area of ​​the second neutron beam line to perform equipment maintenance and sample replacement operations.

[0055] See also Figures 1 to 12 The high-precision second neutron beam line switch for multi-station switching in an embodiment of the present invention includes a shielding support system 2 arranged on the periphery, a switch motion system 1 arranged inside the shielding support system 2, and a beam shielding system connected to both the shielding support system 2 and the switch motion system 1 to achieve beam shielding.

[0056] The shielding support system 2 of this embodiment mainly includes a base 3 with an embedded steel plate inside, the top side of the base 3 is connected to the front shielding support plate 10 and the rear shielding support plate 4 respectively, the top surface of the base 3 is also fixedly connected to the right bottom plate 12 and the left bottom plate 13, the top of the front shielding support plate 10 and the rear shielding support plate 4 are fixedly connected to the bottom surface of the top support plate 6 at the same time, and the top surface of the top support plate 6 is fixedly connected to the left top plate 7 and the right top plate 9, and the front shielding support plate 10 and the rear shielding support plate 4 are respectively provided with shielding filling blocks 5 between the top support plate 6, wherein the shielding filling blocks 5 are used to shield and fill the space other than the motion space, so that the neutron beam can be better shielded at the third station. In this embodiment, the top support plate 6 arranged at the top, the front shielding support plate 10 arranged at the front, the rear shielding support plate 4 arranged at the rear, and the base 3 arranged at the bottom are connected by bolt connection to form an internal hollow rectangular frame structure to accommodate the switch motion system 1 of this embodiment, and also play a corresponding radiation protection role.

[0057] See also Figure 2 , Figure 4 , Figure 5In this embodiment, a beam shielding system is formed by an upper beam stopper assembly 8 arranged at the top, a main beam stopper assembly 17 arranged at the middle, and a lower beam stopper assembly 11 arranged at the bottom. In the third station, the beam shielding system is located on the center line of the beam, so it can be adaptively adjusted to completely shield the neutron beam to ensure that the staff at the rear end of the second neutron beam line switch is below the safe dose. In terms of structural connection, the upper beam stopper assembly 8 of this embodiment is fixed to the top surface of the top support plate 6 by screws, and the lower beam stopper assembly 11 is fixed to the top surface of the base 3 by screws, and the main beam stopper assembly 17 is connected to the switch motion system 1 of this embodiment and is arranged between the upper and lower positions of the upper beam stopper assembly 8 and the lower beam stopper assembly 11. The switching of different working modes is achieved by adjusting the movement of the main beam stopper assembly 17 in the horizontal direction.

[0058] Preferably, the beam stopper main assembly 17, the beam stopper upper assembly 8 and the beam stopper lower assembly 11 of this embodiment are respectively connected by rectangular blocks of different materials, and the plurality of rectangular blocks are fixedly connected by bolts. Fig.12 The beam stopper main assembly 17 of this embodiment includes a boron carbide block 47, a lead block 48, and a carbon steel shielding block 49 which are fixedly connected in sequence by bolts. By using different materials connected in sequence to form a shielding layer, different types of ions can be shielded by different materials respectively, and neutron beams and other particles derived therefrom can also be shielded.

[0059] See also Figure 2 In addition, rectangular holes 101 are provided on the surfaces of the front shielding support plate 10 and the rear shielding support plate 4 of this embodiment. The center of the rectangular hole 101 coincides with the center of the beam, so that the neutron beam transmission will not be affected in the working states of the first and second stations, and the neutron beam can be shielded to the greatest extent in the third station state.

[0060] See also Figures 1 to 12 The switch motion system 1 of this embodiment includes a power transmission system, a control system, a base and a support system, a guide tube and an adjustment system, a collimator and an adjustment system, and a beam stopper main assembly.

[0061] See also Figures 5 to 8The power transmission system of this embodiment includes a motor 21 arranged at one end. The motor 21 is installed on the top surface of the base plate 23 through a mounting base. The power output end of the motor 21 is connected to one end of the screw rod 15 through a coupling 20. By setting the coupling 20, the coaxiality requirement between the transmission shaft of the motor 21 and the screw rod 15 can be reduced to reduce the difficulty of installation. The two ends of the screw rod 15 are respectively installed and positioned by two axially arranged support assemblies 19, and the support assemblies 19 are fixed to the surface of the base plate 23 by screws. The ball nut 26 is connected to the screw rod 15 by a threaded fit and rolling connection, and the ball nut 26 is fixedly connected to the workbench through a nut seat. Therefore, the motor 21 can be used to rotate the coupling 20 to drive the screw rod 15 to rotate accordingly, and the screw rod 15 and the ball nut 26 are connected and rotationally driven by a threaded pair. Under the driving action of the threaded pair, the rotational motion of the screw rod 15 is converted into an axial linear motion of the ball nut 26 relative to the screw rod 15. Accordingly, the ball nut 26 drives the nut seat to move, that is, drives the workbench 50 to move horizontally. Therefore, the forward or backward horizontal movement of the workbench can be achieved by controlling the forward or reverse rotation of the motor 21, and the workbench drives the beam stopper main component 17 to switch the workstations.

[0062] See also Figure 8 The control system of this embodiment includes an encoding system and a mechanical limit switch, wherein the encoding system is composed of a reading head 37 and a grating ruler 38, wherein the grating ruler 38 is installed on the side of the base plate 23. Figure 5 The reading head 37 is mounted on the side of the workbench 50 through the reading head mounting plate, and the reading head 37 scans the scale on the surface of the grating ruler 38 to achieve high-precision positioning and feedback. Preferably, the encoder system of this embodiment adopts an absolute encoder, which can record any position point on the motion stroke, and data loss will not occur in the event of power failure.

[0063] The mechanical limit switch of the present embodiment is mounted on the base plate 23 by screws, and the trigger block is mounted on the bottom of the workbench 50. Specifically, the front and rear ends of the base plate 23 of the present embodiment are respectively mounted with mechanical limit switches and corresponding trigger blocks to play a role in stroke control. When the catheter 16 or the collimator 18 of the present embodiment moves to the beam center position, if the catheter 16 or the collimator 18 continues to move due to encoder failure or other reasons, the mechanical limit switch will be triggered to cut off the power to the motor 21 and stop rotating.

[0064] See also Figures 5 to 7The base and support system of this embodiment mainly include a bottom plate 23, a bottom plate connecting plate 22, a guide rail 14 and a slider 29 arranged at the bottom, wherein the bottom surface of the bottom plate 23 is fixed to the top surface of the right bottom plate 12 and the left bottom plate 13 through the bottom plate connecting plate 22, and two guide rails 14 are installed in parallel on both sides of the top surface of the bottom plate 23 and are symmetrically distributed. The two guide rails 14 are fixed to the surface of the bottom plate 23 by screws, and the surface of the guide rail 14 has sliders 29 that are connected in a sliding manner. There are two sliders 29 that are connected in a sliding manner on the surface of each guide rail 14. Balls are arranged inside the slider 29, so that the slider 29 can slide smoothly relative to the guide rail 14. Preferably, the sliding friction coefficient between the slider 29 and the guide rail 14 of this embodiment is very small, only 0.005. In addition, the slider 29 of this embodiment is installed on the bottom surface of the workbench 50 in a symmetrical manner, and the slider 29 is fixedly connected to the workbench 50 by screws, so that the workbench 50 can slide relative to the base 3.

[0065] See also Figures 5 to 7 The catheter and adjustment system of this embodiment mainly include a catheter 16, an adjustment system and a catheter connecting plate 28, wherein the catheter 16 is a core component, which can be located at the center of the beam and can play a role in transmitting the neutron beam, and the adjustment system has two groups, which are arranged at the bottom of both ends of the catheter 16. The adjustment system is fixedly connected to the catheter 16 through an adjustment mechanism connecting plate 25. The six-dimensional adjustment of the catheter 16 in space can be achieved through the coordinated adjustment of the two groups of adjustment systems, and the adjustment system is fixed to the surface of the workbench 50 through the catheter connecting plate 28.

[0066] The collimator and adjustment system of the present embodiment mainly include a collimator 18 and an adjustment system arranged on the bottom surface of the collimator 18, wherein the collimator 18 is also the core working component of the present embodiment. When the collimator 18 is located on the center line of the beam, it can transmit the neutron beam and absorb stray neutrons. The adjustment system of the present embodiment is arranged at the bottom positions of both axial ends of the collimator 18, and the adjustment mechanism connecting plate 25 and the collimator 18 are fixedly connected through the adjustment system.

[0067] See also Fig. 9 The adjustment system of this embodiment includes an adjustment mechanism base plate 30, a horizontal movement plate 34 and an elevation adjustment plate 35 installed from bottom to top, wherein the adjustment mechanism base plate 30 is fixedly installed on the base, and the horizontal movement plate 34 is installed on the adjustment mechanism base plate 30. The horizontal movement plate 34 is in a rectangular block shape, and horizontal adjustment components 31 are installed on three sides thereof. There are six horizontal adjustment components, of which two are respectively installed on each of the two corresponding sides parallel to the beam direction. The horizontal adjustment components 31 on the two sides are axially symmetrically designed, and two are installed on the sides close to the outside of the two corresponding sides perpendicular to the beam direction, and no horizontal adjustment components are installed on the sides close to the inside.

[0068] The horizontal adjustment components 31 on the two corresponding sides parallel to the beam direction include a horizontal fixing block 51 and a horizontal adjustment screw 33. The horizontal fixing blocks 51 on the two sides are axially symmetrically designed and are used to fix the limited horizontal motion plate 34. The horizontal fixing blocks 51 are fixedly installed on the adjustment mechanism base plate 30 by screws in the vertical direction. Each horizontal fixing block 51 is provided with a horizontal adjustment screw 33 in the horizontal direction. The horizontal adjustment screw 33 passes through the horizontal fixing block 51 and the bottom of one end directly contacts the horizontal motion plate 34, and the other end extends outside the horizontal fixing block 51. By rotating the horizontal adjustment screw 33, the position of the horizontal motion plate 34 in the horizontal direction is adjusted under the action of the threaded pair.

[0069] The two horizontal adjustment components 31 on the side closer to the outside of the two corresponding side surfaces perpendicular to the beam direction are symmetrical about the central axis, and each horizontal adjustment component includes a horizontal fixed block 51, and a group of push rod components 53 and a group of pull rod components 52 connected by the horizontal fixed block 51, wherein the push rod component 53 includes a rotating screw and a nut, and the rotating screw passes through the horizontal fixed block and the bottom of one end directly touches the horizontal motion plate 34, and the other end extends to the outside of the horizontal fixed block 51, and by rotating the screw, the position of the horizontal motion plate 34 in the horizontal direction is pushed and adjusted under the action of the threaded pair; wherein the pull rod component 52 includes a threaded pull rod, a nut and a step block, and the step block 54 is fixedly installed on the horizontal motion plate 34 by screws, and the bottom of the pull rod passes through the horizontal fixed block and is fixedly connected to the step block 54, and the pull rod is fixedly connected to the horizontal motion plate 34 through the step block 54, and the other end extends to the outside of the horizontal fixed block 51, and by rotating the nut, the position of the horizontal motion plate 34 in the horizontal direction is pulled and adjusted under the action of the threaded pair.

[0070] The elevation adjustment plate 35 is a rectangular plate, which is installed above the horizontal motion plate 34 through the elevation adjustment assembly 32. The position of the elevation adjustment plate 35 in space can be adjusted by adjusting the nut of the elevation adjustment assembly 32. It should be noted that the adjustment system in the present invention is similar in structure and principle to the bottom adjustment mechanism in a neutron guide tube system with a multi-stage collimation adjustment mechanism in Chinese Patent Application No. 2019110535744, but the difference lies in the adjustment structure and adjustment method in the horizontal direction. The horizontal adjustment assembly 31 in the present invention is divided into two types, one of which is used for horizontal adjustment in the direction parallel to the beam line, and the other is used for horizontal adjustment in the direction perpendicular to the beam line, wherein the horizontal adjustment in the direction parallel to the beam line is bidirectional adjustment, and the horizontal adjustment in the direction perpendicular to the beam line is unidirectional push-pull adjustment, that is, a pull rod assembly 52 and a push rod assembly 53 capable of unilateral push-pull are used. Due to the space limitation on the opposite side, a unilaterally operated adjustment assembly is required in the direction perpendicular to the beam. There is enough operating space along the beam line direction, so the adjustment is performed by screw-to-top method, which is simple, accurate, convenient and fast.

[0071] When the beam stopper main assembly 17 of the present embodiment is located on the beam centerline, the beam shielding system is formed by the beam stopper upper assembly 8, the beam stopper main assembly 17 and the beam stopper lower assembly 11, which can block the beam to the greatest extent. Since the actual three-dimensional size of the beam shielding system needs to be 20 mm larger than the theoretically calculated size, the error between the centerline of the beam shielding system and the centerline of the beam is less than 10 mm, and this accuracy can be ensured through processing and assembly.

[0072] See also Fig.12 The beam stopper main assembly 17 of this embodiment is fixedly mounted on the surface of the workbench 50, and can switch between three working states with the horizontal movement of the workbench 50. The surface of the beam stopper main assembly 17 is provided with an elevation target seat 46 and a horizontal target seat 45, so that alignment measurement can be performed using an alignment device. In addition, target seats are respectively provided on the surfaces of the guide tube 16 and the collimator tube 18 of this embodiment, so that alignment calibration can be performed using a measuring arm and position detection and alignment installation can be performed using a laser tracker.

[0073] The catheter 16, the beam stopper main assembly 17 and the collimator 18 of this embodiment are all installed on the surface of the workbench 50 and arranged in parallel, wherein the beam stopper main assembly 17 is located between the catheter 16 and the collimator 18, and the catheter 16 and the collimator 18 are located on both sides of the beam stopper main assembly 17. Since sufficient space is required to switch the positions of different working modes during actual operation, no shielding can be performed on this travel space. This embodiment requires minimizing the gap between the beam stopper main assembly 17 and the catheter 16 and the gap between the beam stopper main assembly 17 and the collimator 18, which can reduce the travel space required for switching the working mode and enhance the shielding effect.

[0074] See also Figure 7 , Fig.10 and Fig.11 , the present embodiment is further provided with an auxiliary adjustment mechanism, wherein the auxiliary adjustment mechanism comprises an auxiliary adjustment plate 39, an auxiliary adjustment screw 40 and a fixing screw 43, wherein the auxiliary adjustment mechanism can perform auxiliary adjustment on the bottom plate connecting plate 22, firstly, the auxiliary adjustment mechanism is fixed to the side of the left bottom plate 13 and the right bottom plate 12 by the fixing screw 41, wherein one group is installed on the front and rear end faces of the left bottom plate 13, two groups are installed on the left side of the left bottom plate 13, one group is installed on the front and rear end faces of the right bottom plate 12, and two groups are installed on the right side, by adjusting the auxiliary adjustment screw 40 of the auxiliary adjustment mechanism 42, the position of the bottom plate connecting plate 22 in the horizontal direction can be adjusted, and the elevation direction is adjusted by adding or removing gaskets, since the installation accuracy of the bottom plate connecting plate 22 is low, it only needs to be controlled within 5mm, so there is no need for precise adjustment, after the adjustment is completed, it is locked by two fixing screws 43, and then all the auxiliary adjustment mechanisms and the target seat with pin are removed, since the target seat with pin can be accurately positioned by the pin and the bottom plate connecting plate 22, the position accuracy of the target seat will not be affected by reinstalling it after removal.

[0075] See also Figures 1 to 12 This embodiment also discloses a method for aligning a high-precision second neutron beam line switch for multi-station switching, wherein the guide tube 16 and the collimating tube 18 are aligned and installed in the correct position, so that the beam shielding system ensures the position accuracy through design, processing and installation, wherein the basic alignment and installation method includes the following steps:

[0076] Step S1: Calibration, by establishing the relative position relationship between the target component and the target seat in three-dimensional space, adjusting the position of the target component by adjusting the target seat, and calibrating the catheter 16 and the collimator 18 respectively.

[0077] First, the catheter 16 is calibrated: the catheter 16 is placed on an optical platform, and the measuring arm is used to measure the inner side surface and the front and rear end surfaces of the catheter 16, and then the catheter target seat on the outer surface of the catheter 16 is measured to establish the spatial position relationship between the inner dimension of the catheter 16 and the catheter target seat. Since the inner surface of the catheter 16 has a high machining accuracy and the theoretical position of the inner surface of the catheter 16 in space is known, the theoretical position coordinates of the catheter target seat in space are obtained. It is also noted that the calibration process of the alignment tube in this embodiment is the same as that of the catheter.

[0078] Then, the collimator 18 is calibrated: the collimator 18 is placed on an optical platform, and the inner side surface and the front and rear end surfaces of the collimator 18 are measured using a measuring arm, and then the target seat on the outer surface of the collimator 18 is measured, and the spatial position relationship between the inner size of the collimator 18 and the collimator target seat is established, and the theoretical position coordinates of the collimator target seat in space are obtained;

[0079] Regarding the calibration of the beam stopper main component 17: Since the positioning requirements for the beam stopper main component 17 and the base plate connecting plate 22 are relatively low in precision, all processing and installation errors can be ignored and no calibration is required. Only the drawing dimensions need to be used to directly obtain the theoretical position coordinates of the target seat in space. Since the actual size of the beam stopper main component 17 is much larger than the theoretical calculated size, and far larger than the errors caused by processing and assembly, assembly positioning is directly performed based on the rough positioning of the base plate connecting plate 22.

[0080] Step S2: Install the bottom plate connecting plate 22 of the base 3. First, use the laser tracker to align and lay out the lines. Use the laser tracker to set eight points on the ground, where the points in the horizontal and vertical directions are connected in pairs. Finally, four straight lines intersect to form a rectangular frame. The length and width of the rectangular frame are equal to the length and width of the base 3. Then, install the base 3 with the embedded steel plate on the top on the ground. The four side lines of the bottom surface of the base 3 coincide with the four straight lines on the ground. Then, fix the left bottom plate 13, the right bottom plate 12, and the beam stopper lower assembly 11 on the base 3 by bolts, and then The base plate connecting plate 22 is installed and fixed, and there is no need to tighten the fixing screws during the installation process. The eight groups of auxiliary adjustment mechanisms are respectively installed on the right base plate 12 and the left base plate 13. The target seat with pins is installed on the base plate connecting plate 22 by means of positioning pins and screws. The position coordinates of the target seat are monitored by a laser tracker, and the eight groups of auxiliary adjustment mechanisms 42 are adjusted. The elevation direction is adjusted by adding or reducing gaskets. When the coordinate measurement value of the target seat and the theoretical coordinate deviation are less than 3mm, the base plate connecting plate 22 is installed to the theoretical position, and then the target seat and the auxiliary adjustment mechanism 42 are removed, and finally the fixing screws 36 are tightened.

[0081] Step S3: Install the switch motion system. First, assemble the power transmission system, control system, base and support system so that the workbench 50 can run smoothly. Then install the whole system on the bottom plate connecting plate 22, position it by positioning pins and lock it with bolts. Then, install the beam stopper main assembly connecting plate 44 on the workbench 50 by positioning pins, and install the beam stopper main assembly 17 on the beam stopper main assembly connecting plate 44. Use a laser tracker to measure the elevation target seat on the beam stopper main assembly 17. When the error between the measured value and the theoretical value of the elevation target seat in the elevation direction and along the beam direction is less than 5mm, the beam stopper main assembly 17 is installed in place in the elevation direction and along the beam direction. Since the installation error of the bottom plate connecting plate is 3mm, and all the components on the bottom plate connecting plate 22 are positioned by positioning pins and then bolted, the accuracy loss is very small. The error requirement of the elevation target seat on the beam stopper main assembly 17 in the elevation direction and along the beam line direction is less than 5 mm, so no adjustment process is required, and the beam stopper main assembly 17 can be aligned and installed in place in these two directions; in this process, the elevation target seat is perpendicular to the value in the beam direction and does not need to be adjusted, and then the catheter connecting plate 28, the adjustment mechanism at the bottom of the catheter 16 and the catheter 16 are installed on the workbench, and the collimating tube 18 and the adjustment mechanism at the bottom are installed on the workbench 50.

[0082] Step S4: Collimation installation and debugging:

[0083] First, the motor 21 and the encoder system are powered on, and the motor 21 drives the workbench 50 to achieve horizontal movement. The laser tracker is used to detect the horizontal target seat on the beam stop block main component 17. Since the encoder system and the ball screw system are used in this embodiment, the minimum step value of the horizontal movement of the workbench 50 is much smaller than the alignment installation accuracy. When the deviation between the measured value and the theoretical value of the horizontal target seat 45 in the direction perpendicular to the beam, that is, in the horizontal movement direction, is less than 1 mm, the motor 21 stops rotating and the encoder records the current position, that is, the beam stop block main component 17 has been installed to the theoretical position in the three-dimensional direction.

[0084] Then the motor 21 rotates again, and the workbench 50 moves horizontally for a theoretical length of L1. At this time, the center of the catheter 16 is located near the center of the beam. The target seat on the catheter 16 is detected by a laser tracker, and the two sets of adjustment systems at the bottom are adjusted. During the adjustment process, if the measured value and the theoretical value of the target seat deviate greatly, the workbench can also be moved for adjustment. When the deviation between the coordinate measurement value of the target seat and the calibrated theoretical coordinate is less than 0.05mm, the encoder records the current position, and the catheter 16 is installed to the theoretical position.

[0085] Then, the motor 21 is rotated to make the workbench 50 move horizontally by the theoretical length L2. At this time, the center of the collimator 18 is located near the center of the beam. The target seat on the collimator 18 is detected by a laser tracker, and the two sets of adjustment systems at the bottom are adjusted. During the adjustment process, if the measured value and the theoretical value of the target seat have a large deviation, the workbench can be moved for adjustment. When the deviation between the coordinate measurement value of the target seat and the calibrated theoretical coordinate is less than 0.05mm, the encoder records the current position, that is, the collimator 18 is installed at the theoretical position, and the collimation installation is now completed.

[0086] Step S5: finally install the front shielding support plate 10, the rear shielding support plate 4, the top support plate 6, the left top plate 7, the beam stopper upper assembly 8, and the right top plate 9, thereby completing the installation of the entire multi-station switching high-precision second neutron beam line switch.

[0087] In addition, the beam stopper main assembly 17 in the technical solution of the embodiment of the present invention is located in the middle position, and the guide tube 16 and the collimator 18 are located on both sides respectively. The encoder used in the encoding system can record any position in the motion stroke, and will still be located in the working position without change in the case of power failure, and the recorded position point will not be lost. In order to enhance the shielding effect, the distance between the guide tube 16 and the collimator 18 and the beam stopper main assembly 17 is small and there is no adjustment space. Therefore, in the adjustment system at the bottom, a single-side push-pull method is used for adjustment perpendicular to the beam direction, and a bolt-to-top method is used for adjustment along the beam direction, which makes the adjustment method more convenient.

[0088] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A high-precision second neutron beam line switch with multi-station switching, characterized in that: The invention comprises a shielding support system arranged at the periphery, a switch motion system arranged inside the shielding support system, and a beam shielding system connected to the shielding support system and the switch motion system to realize beam shielding; the switch motion system realizes switching of three working modes by horizontal movement, including: a first mode, the guide tube is located on the beam center line for transmitting the neutron beam; a second mode, the collimator is located on the beam center line for transmitting and collimating the neutron beam; a third mode, the beam stopper main assembly is located on the beam center line for cutting off the neutron beam; The shielding support system includes a base with an embedded steel plate inside, the front and rear sides of the top of the base are respectively connected to a front shielding support plate and a rear shielding support plate, the top surface of the base is fixedly connected to a right bottom plate and a left bottom plate, the tops of the front shielding support plate and the rear shielding support plate are fixedly connected to the top support plate at the same time, the top surface of the top support plate is fixedly connected to the left top plate and the right top plate, shielding filling blocks are respectively provided between the front shielding support plate and the rear shielding support plate and the top support plate, the top support block, the front shielding support plate, the rear shielding support plate and the base together form an internal hollow frame structure and accommodate the switch motion system, and the surfaces of the front shielding support plate and the rear shielding support plate are provided with through holes that can be axially opposite to the central channel of the catheter or the collimator and coincide with the beam center; The beam shielding system comprises an upper beam stopper assembly connected to the top support plate, a main beam stopper assembly connected to the switch motion system, and a lower beam stopper assembly connected to the base. When the second neutron beam line switch is in the third position, the main beam stopper assembly of the beam shielding system can be located at the center line of the beam and play a shielding role. The switch motion system comprises a power transmission system, a control system, a base and a support system, a guide tube and an adjustment system, and a collimator and an adjustment system.

2. A high-precision second neutron beam line switch with multi-station switching according to claim 1, characterized in that: The power transmission system includes a motor installed on the top surface of the base plate. The power output end of the motor is connected to the screw rod through a coupling. The two ends of the screw rod are respectively installed and positioned through support components. The screw rod is rollingly connected to the ball nut, and the ball nut is fixedly connected to the workbench. The motor drives the screw rod to rotate and the ball nut drives the workbench to move linearly.

3. The high-precision second neutron beam line switch with multi-station switching according to claim 2, characterized in that: The control system includes a coding system and a mechanical limit switch. The coding system includes a grating ruler arranged on the side of the base plate and a plurality of reading heads installed on the surface of the workbench. The reading heads realize positioning and feedback by scanning the scales on the surface of the grating ruler. The coding system uses an absolute encoder to record the stroke position and save data. The mechanical limit switch is installed on the surface of the base plate and cooperates with a trigger block installed at the bottom of the workbench to realize stroke control.

4. The high-precision second neutron beam line switch with multi-station switching according to claim 3, characterized in that: The base and support system include a bottom plate, a bottom plate connecting plate, a guide rail and a slider arranged at the bottom. The bottom surface of the bottom plate is fixed to the top surfaces of the right bottom plate and the left bottom plate through the bottom plate connecting plate. Two parallel guide rails are symmetrically installed on the surface of the bottom plate. The guide rails are slidably connected to the slider. The slider is connected to the bottom surface of the workbench and cooperates with the screw rod and the ball nut to slide.

5. The high-precision second neutron beam line switch with multi-station switching according to claim 4, characterized in that: The catheter and adjustment system include a catheter, an adjustment system and a catheter connecting plate. The catheter is movably arranged at the center of the beam through the adjustment system, and is used to transmit the neutron beam in the first mode; the collimator and adjustment system include a collimator and an adjustment system. The collimator can be moved to the center line of the beam through the adjustment system, and is used to transmit and collimate the neutron beam in the second mode; the beam stopper main component is fixed on the top surface of the workbench, moves horizontally with the workbench, and realizes the switching of three working states of catheter transmission, collimator collimation and beam truncation in the first, second and third modes respectively. The surface of the beam stopper main component is provided with an elevation target seat and a horizontal target seat for collimation measurement.

6. The high-precision second neutron beam line switch with multi-station switching according to claim 5, characterized in that: The beam stopper main component, the beam stopper upper component and the beam stopper lower component are respectively formed by stacking and connecting different material layers in sequence.

7. The high-precision second neutron beam line switch with multi-station switching according to claim 6, characterized in that: The adjustment system includes an adjustment mechanism base plate, a horizontal movement plate and an elevation adjustment plate installed from bottom to top, wherein the adjustment mechanism base plate is fixedly installed on the base, and the horizontal movement plate is installed on the adjustment mechanism base plate. The horizontal movement plate is in the shape of a rectangular block, and horizontal adjustment components are installed on three sides thereof. There are six horizontal adjustment components, two of which are installed on each of the two corresponding sides parallel to the beam direction. The horizontal adjustment components on the two sides are axially symmetrical in design, and two are installed on the sides close to the outside of the two corresponding sides perpendicular to the beam direction, and no horizontal adjustment components are installed on the sides close to the inside.

8. A method for collimating and installing a high-precision second neutron beam line switch using the multi-station switching according to claims 1-7, characterized in that: The following steps are involved: Step S1: calibration, by establishing the relative position relationship between the target component and the target seat in three-dimensional space, adjusting the position of the target component by adjusting the target seat; calibrating the catheter and the collimator respectively; Step S2: Install the base plate connecting plate of the base, align and install it using a laser tracker; Step S3: Install the switch motion system, position it by means of positioning pins and lock it by means of bolt connections; Step S4: collimation installation and debugging, using a laser tracker to detect and adjust the positions of the beam stopper main assembly, the guide tube and the collimator; Step S5: finally installing the front shielding support plate, the rear shielding support plate, the top support plate, the left top plate, the beam stopper upper assembly, and the right top plate, thereby completing the installation of the entire multi-station switching high-precision second neutron beam line switch.

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