阅读说明：本技术 一种硬x射线自由电子激光固体衰减器及衰减控制方法 (Hard X-ray free electron laser solid attenuator and attenuation control method ) 是由 佟亚军 江怀东 范家东 于 2020-05-19 设计创作，主要内容包括：本发明公开了一种硬X射线自由电子激光固体衰减器及衰减控制方法,包括前衰减臂、后衰减臂、真空腔体、运动控制系统和控制电脑系统,所述前衰减臂的衰减片一和后衰减臂的衰减片二在真空腔体内相对设置,运动控制系统分别与前衰减臂和后衰减臂连接,用于控制前衰减臂和后衰减臂相对运动,使得衰减片一和衰减片二在X射线自由电子激光光束上组合形成不同的厚度满足衰减需求,控制电脑系统与运动控制系统连接,用于根据衰减需求计算前衰减臂和后衰减臂的运动距离并向运动控制系统发出控制指令。本发明通过调节衰减片之间的相对位移距离即可实现不同能量下、不同衰减量级衰减片厚度连续调节,满足多种衰减需求。(The invention discloses a hard X-ray free electron laser solid attenuator and an attenuation control method, wherein the hard X-ray free electron laser solid attenuator comprises a front attenuation arm, a rear attenuation arm, a vacuum cavity, a motion control system and a control computer system, wherein a first attenuation sheet of the front attenuation arm and a second attenuation sheet of the rear attenuation arm are oppositely arranged in the vacuum cavity, the motion control system is respectively connected with the front attenuation arm and the rear attenuation arm and is used for controlling the front attenuation arm and the rear attenuation arm to relatively move, so that the first attenuation sheet and the second attenuation sheet are combined on an X-ray free electron laser beam to form different thicknesses to meet attenuation requirements, and the control computer system is connected with the motion control system and is used for calculating the motion distance of the front attenuation arm and the rear attenuation arm according to the attenuation requirements and sending a control command to the motion control system. The invention can realize the continuous adjustment of the thickness of the attenuation sheets with different energies and different attenuation magnitudes by adjusting the relative displacement distance between the attenuation sheets, thereby meeting various attenuation requirements.)

1. A hard X-ray free electron laser solid attenuator is characterized in that: comprises a front attenuation arm (2), a rear attenuation arm (3), a vacuum cavity (4), a motion control system (5) and a control computer system (6), the attenuation sheet I (21) of the front attenuation arm (2) and the attenuation sheet II (301) of the rear attenuation arm (3) are oppositely arranged in the vacuum cavity (4), the motion control system (5) is respectively connected with the front attenuation arm (2) and the rear attenuation arm (3), used for controlling the relative movement of the front attenuation arm (2) and the rear attenuation arm (3) to ensure that the attenuation sheet I (21) and the attenuation sheet II (301) are combined on the X-ray free electron laser beam (1) to form different thicknesses to meet the attenuation requirement, a control computer system (6) is connected with a movement control system (5), the damping device is used for calculating the movement distance of the front damping arm (2) and the rear damping arm (3) according to the damping requirement and sending a control command to the movement control system (5).

2. The hard X-ray free electron laser solid state attenuator of claim 1, wherein: preceding decay arm (2) are including decay piece (21), cooling fixture (203), bellows (204), fixed arm (205) and motion actuating mechanism (207), the one end of cooling fixture (203) is inserted vacuum cavity (4) and is used for the centre gripping to be located vacuum cavity (4) decay piece (21), and the other end is connected with motion actuating mechanism (207) through fixed arm (205), and motion actuating mechanism (207) are connected with motion control system (5), and the part cover that cooling fixture (203) are located vacuum cavity (4) outside is equipped with bellows (204) and guarantees that decay piece (21) are located vacuum cavity (4) all the time when moving.

3. The hard X-ray free electron laser solid state attenuator of claim 2, wherein: and a first cooling water pipe (206) for cooling the attenuation sheet (21) is arranged in the first cooling clamping mechanism (203).

4. The hard X-ray free electron laser solid state attenuator of claim 1, wherein: back decay arm (3) are including decay piece two (301), cooling fixture two (302), bellows two (303), fixed arm two (304) and motion actuating mechanism two (306), the one end of cooling fixture two (302) is inserted vacuum cavity (4) and is used for the centre gripping to be located vacuum cavity (4) interior decay piece two (301), and the other end is connected with motion actuating mechanism two (306) through fixed arm two (304), and motion actuating mechanism two (306) are connected with motion control system (5), and the part cover that cooling fixture two (302) are located vacuum cavity (4) is equipped with bellows two (303) and is located vacuum cavity (4) all the time when guaranteeing that decay piece two (301) move.

5. The hard X-ray free electron laser solid state attenuator of claim 4, wherein: and a second cooling water pipe (305) for cooling the second attenuation sheet (301) is arranged in the second cooling clamping mechanism (302).

6. The hard X-ray free electron laser solid state attenuator of claim 1, wherein: the first attenuation sheet (21) and the second attenuation sheet (301) are both right-angle trapezoids, the two right-angle trapezoids are the same in shape and size, one end, where the longer bottom edge of the first attenuation sheet (21) is located, is connected with the first cooling clamping mechanism (203), one end, where the longer bottom edge of the second attenuation sheet (301) is located, is connected with the second cooling clamping mechanism (302), the oblique edge of the first attenuation sheet (21) and the oblique edge of the second attenuation sheet (301) are oppositely arranged in the vacuum cavity (4), and the right-angle edge of the first attenuation sheet (21) is a light-facing surface.

7. The hard X-ray free electron laser solid state attenuator of claim 1, wherein: the attenuation sheet I (21) comprises a rectangular part (201) and a triangular part (202), wherein the rectangular part (201) is made of diamond and is responsible for resisting high heat load and single pulse damage of free electron laser, and the triangular part (202) is made of monocrystalline silicon or boron carbide and is used for adjusting the thickness of a passing position of the X-ray free electron laser beam (1).

8. The hard X-ray free electron laser solid state attenuator of claim 1, wherein: the second attenuation sheet (301) is made of monocrystalline silicon or boron carbide and is used for adjusting the thickness of the passing position of the X-ray free electron laser beam (1).

9. The method for controlling attenuation of a hard X-ray free electron laser according to any one of claims 1 to 8, comprising the steps of:

s1: calculating linear absorption coefficients of the diamond and the monocrystalline silicon or the boron carbide under different energies by using X-ray calculation software XOP/xCrossSec;

s2: forming an interpolation function between the linear absorption coefficients and energy of the diamond and the monocrystalline silicon or the boron carbide according to the data calculated in S1, and calculating the linear absorption coefficient mu 1 of the diamond sheet and the linear absorption coefficient mu 2 of the monocrystalline silicon or the boron carbide according to the energy when attenuation is needed;

s3: assuming that the attenuation coefficient of a diamond portion with a thickness of t1 is a1, the attenuation coefficient of a monocrystalline silicon or boron carbide portion with a thickness of t2 is a2, the required attenuation coefficient is a0, and a0 is a1 a1, the formula of the attenuation coefficient is expressed as a-e^-μtCalculating the thickness t2 of the needed monocrystalline silicon or boron carbide when the thickness t1 of the diamond is calculated,

s4: setting the included angle between the right-angle side and the oblique side of the attenuation sheet I and the attenuation sheet II as theta, calculating the movement distance X of the front attenuation arm and the rear attenuation arm according to the geometric parameters of the attenuation sheet I and the attenuation sheet II and the point 0 which is the superposition position of the shorter bottom sides of the right-angle trapezoidal attenuation sheet I and the attenuation sheet II and the optical axis of the X-ray free electron laser,

s5: and the control computer system sends a control instruction to the motion control system according to the calculation result to simultaneously move the front attenuation arm and the rear attenuation arm by the x distance.

10. The method of claim 9, wherein the attenuation control of the hard X-ray free electron laser comprises: in the step S4, it is set that only the front damping arm or the rear damping arm is controlled to move, the current positions of both damping arms are set to be x0, the movement distance x1 of the front damping arm or the rear damping arm is calculated,

and the control computer system sends a control command to the motion control system according to the calculation result to move the front damping arm or the rear damping arm by x1 distance.

Technical Field

The invention relates to a hard X-ray free electron laser solid attenuator and an attenuation control method, and belongs to the field of hard X-ray free electron laser beam lines.

Background

The X-ray free electron laser (XSEL) has the characteristics of high brightness, high coherence and ultrashort pulse, and is an advantage for basic scientific research. The ultra-high brightness of the X-ray free electron laser enables the X-ray free electron laser to damage any substance under the condition of focusing, so that the X-ray free electron laser is required to be attenuated by 1-6 orders of magnitude or even more during debugging and experiment preparation in the experiment. At present, materials such as monocrystalline silicon, diamond, boron carbide and the like are generally adopted in a hard X-ray wave band, and are inserted into a light path at the front end of a beam line to realize attenuation, and attenuation sheet combinations with different thicknesses are required to be adopted for realizing different energies and different attenuation magnitudes. The combination can not realize continuous adjustment, and simultaneously dozens of attenuation pieces are needed to work in cooperation because of more combinations. At the same time, the attenuation sheet of the first sheet irradiated by the free electron laser is also responsible for absorbing the extremely high thermal load, which requires the ability to withstand damage and carry away the thermal load.

In summary, the existing solid attenuator system is very complex, has no continuous adjustability and weak damage resistance.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the existing solid attenuator system is very complex, has no continuous adjustability and has weak damage resistance.

In order to solve the above problems, the technical solution of the present invention is to provide a hard X-ray free electron laser solid attenuator, which is characterized in that: the X-ray free electron laser beam attenuation device comprises a front attenuation arm, a rear attenuation arm, a vacuum cavity, a motion control system and a control computer system, wherein a first attenuation piece of the front attenuation arm and a second attenuation piece of the rear attenuation arm are oppositely arranged in the vacuum cavity, the motion control system is respectively connected with the front attenuation arm and the rear attenuation arm and used for controlling the front attenuation arm and the rear attenuation arm to move relatively, so that the first attenuation piece and the second attenuation piece are combined on an X-ray free electron laser beam to form different thicknesses to meet attenuation requirements, and the control computer system is connected with the motion control system and used for calculating the motion distance of the front attenuation arm and the rear attenuation arm according to the attenuation requirements and sending a control command to the motion control system.

Preferably, preceding decay arm includes decay piece one, cooling fixture I, bellows one, fixed arm one and motion actuating mechanism one, the one end of cooling fixture I is inserted the vacuum cavity and is used for the centre gripping to be located the interior decay piece one of vacuum cavity, and the other end passes through fixed arm one and is connected with motion actuating mechanism one, and motion actuating mechanism one is connected with motion control system, and the part cover that cooling fixture I is located the vacuum cavity outside is equipped with the bellows and guarantees that the decay piece is located the vacuum cavity all the time when moving.

Preferably, a first cooling water pipe for cooling the attenuation sheet is arranged in the first cooling clamping mechanism.

Preferably, the rear attenuation arm comprises a second attenuation sheet, a second cooling clamping mechanism, a second corrugated pipe, a second fixed arm and a second motion driving mechanism, one end of the second cooling clamping mechanism is inserted into a vacuum cavity and used for clamping the second attenuation sheet located in the vacuum cavity, the other end of the second cooling clamping mechanism is connected with the second motion driving mechanism through the second fixed arm, the second motion driving mechanism is connected with a motion control system, and the part, located outside the vacuum cavity, of the second cooling clamping mechanism is sleeved with the second corrugated pipe to ensure that the second attenuation sheet is located in the vacuum cavity all the time when moving.

Preferably, a cooling water pipe II for cooling the attenuation sheet II is arranged in the cooling clamping mechanism II.

Preferably, the first attenuation sheet and the second attenuation sheet are both right-angle trapezoids, the two right-angle trapezoids are the same in shape and size, one end, where the longer bottom edge of the first attenuation sheet is located, of the first attenuation sheet is connected with the first cooling clamping mechanism, one end, where the longer bottom edge of the second attenuation sheet is located, of the second cooling clamping mechanism is connected with the second cooling clamping mechanism, the bevel edge of the first attenuation sheet and the bevel edge of the second attenuation sheet are oppositely arranged in the vacuum cavity, and the right-angle edge of the first attenuation sheet is a.

Preferably, the attenuation sheet comprises a rectangular part and a triangular part, the rectangular part is made of diamond and is responsible for resisting high heat load and single pulse damage of the free electron laser, and the triangular part is made of monocrystalline silicon or boron carbide and is used for adjusting the thickness of the passing position of the X-ray free electron laser beam.

Preferably, the material of the second attenuation sheet is monocrystalline silicon or boron carbide and is used for adjusting the thickness of the passing position of the X-ray free electron laser beam.

Another technical solution of the present invention is to provide a method for controlling attenuation of a hard X-ray free electron laser, comprising the steps of:

s1: calculating linear absorption coefficients of the diamond and the monocrystalline silicon or the boron carbide under different energies by using X-ray calculation software XOP/xCrossSec;

s2: forming an interpolation function between the linear absorption coefficients and energy of the diamond and the monocrystalline silicon or the boron carbide according to the data calculated in S1, and calculating the linear absorption coefficient mu 1 of the diamond sheet and the linear absorption coefficient mu 2 of the monocrystalline silicon or the boron carbide according to the energy when attenuation is needed;

s3: assuming that the attenuation coefficient of a diamond portion with a thickness of t1 is a1, the attenuation coefficient of a monocrystalline silicon or boron carbide portion with a thickness of t2 is a2, the required attenuation coefficient is a0, and a0 is a1 a1, the formula of the attenuation coefficient is expressed as a-e^-μtCalculating the thickness t2 of the needed monocrystalline silicon or boron carbide when the thickness t1 of the diamond is calculated,

s4: setting the included angle between the right-angle side and the oblique side of the attenuation sheet I and the attenuation sheet II as theta, calculating the movement distance X of the front attenuation arm and the rear attenuation arm according to the geometric parameters of the attenuation sheet I and the attenuation sheet II and the point 0 which is the superposition position of the shorter bottom sides of the right-angle trapezoidal attenuation sheet I and the attenuation sheet II and the optical axis of the X-ray free electron laser,

s5: and the control computer system sends a control instruction to the motion control system according to the calculation result to simultaneously move the front attenuation arm and the rear attenuation arm by the x distance.

Preferably, the step S4 sets that only the front damping arm or the rear damping arm is controlled to move, the current positions of both damping arms are x0, the movement distance x1 of the front damping arm or the rear damping arm is calculated,

and the control computer system sends a control command to the motion control system according to the calculation result to move the front damping arm or the rear damping arm by x1 distance.

Compared with the prior art, the invention has the beneficial effects that:

the invention adopts two sets of attenuation sheets which are arranged oppositely, can realize the thickness adjustment of the attenuation sheets with different energies and different attenuation magnitudes by adjusting the relative displacement distance between the attenuation sheets, has simple structure and adjustment method, can realize the continuous adjustment of the thickness of the attenuation sheets by controlling the intelligent control of a computer system, and meets various attenuation requirements; meanwhile, the light-facing surface of the front attenuation sheet is made of diamond to resist high heat load and single pulse damage of X-ray free electron laser, and the damage resistance of the solid attenuator is greatly improved.

Drawings

FIG. 1 is a schematic diagram of a solid-state attenuator of hard X-ray free electron laser according to the present invention;

FIG. 2 is a schematic diagram of the operation of a hard X-ray free electron laser solid-state attenuator according to the present invention;

FIG. 3 is a left side view of the front dampening arm;

FIG. 4 is a front view of the front dampening arm;

FIG. 5 is a left side view of the rear damping arm;

FIG. 6 is a front view of the rear damping arm;

FIG. 7 is a schematic diagram of the attenuation control method of hard X-ray free electron laser according to the present invention.

Detailed Description

In order to make the invention more comprehensible, preferred embodiments are described in detail below with reference to the accompanying drawings.

As shown in fig. 1 and fig. 2, the hard X-ray free electron laser solid attenuator of the present invention includes a set of front attenuation arms 2, a set of rear attenuation arms 3, a set of vacuum chamber 4, a motion control system 5, and a control computer system 6.

As shown in fig. 3 and 4, the front damping arm 2 includes a first right-angle trapezoidal damping fin 21, a first cooling clamp mechanism 203, a first cooling water pipe 206, a first bellows 204, a first fixing arm 205, and a first motion drive mechanism 207; the attenuation sheet I21 is composed of a rectangular portion 201 and a triangular portion 202, the rectangular portion 201 is made of diamond and is responsible for resisting high heat load and single pulse damage of free electron laser, and the triangular portion 202 is made of monocrystalline silicon or boron carbide and is used for adjusting the thickness of a passing position of the X-ray free electron laser beam 1. The diamond and the monocrystalline silicon or the boron carbide can be obtained by adopting diamond plated on the monocrystalline silicon or the boron carbide, and the included angle of the two edges of the right-angled triangle of the monocrystalline silicon or the boron carbide inserted into the light path is calculated according to the working energy range, the attenuation requirement and the movable range.

One end of the first cooling clamping mechanism 203 is inserted into the vacuum cavity 4 and used for clamping the first attenuator 21 positioned in the vacuum cavity 4, the other end of the first cooling clamping mechanism is connected with the first motion driving mechanism 207 through the first fixing arm 205, the first fixing arm 205 is installed on the first motion driving mechanism 207 to realize transmission from linear displacement outside the vacuum cavity 4 to displacement inside the vacuum cavity 4, and the first motion driving mechanism 207 is connected with the motion control system 5. The cooling clamping mechanism I203 tightly clamps the right-angle trapezoid attenuation piece I21 together through metal indium to form good heat conductivity, a cooling water pipe I206 is communicated with the middle of the cooling clamping mechanism 203 to cool the attenuation piece I21, and a water inlet and a water outlet of the cooling water pipe I206 are located at the top end of the cooling clamping mechanism I203. The part of the cooling clamping mechanism I203, which is positioned outside the vacuum cavity 4, is sleeved with a corrugated pipe I204 which is used for separating a right-angle trapezoidal attenuation sheet I21 working in the vacuum cavity 4 from a motion driving mechanism I207 working in the atmosphere, so that the attenuation sheet I21 is always positioned in the vacuum cavity 4 when in motion.

As shown in fig. 5 and 6, the rear attenuation arm 3 includes a second right-angle trapezoidal attenuation piece 301, a second cooling clamping mechanism 302, a second bellows 303, a second fixed arm 304 and a second motion driving mechanism 306, one end of the second cooling clamping mechanism 302 is inserted into the vacuum cavity 4 for clamping the second attenuation piece 301 located in the vacuum cavity 4, the other end of the second cooling clamping mechanism 302 is connected with the second motion driving mechanism 306 through the second fixed arm 304, the second fixed arm 304 is mounted on the second motion driving mechanism 306 to realize transmission of linear displacement from the outside of the vacuum cavity 4 to the inside of the vacuum cavity 4, and the second motion driving mechanism 306 is connected with the motion control system 5. The second right-angle trapezoidal attenuation piece 301 is tightly clamped together by the second cooling clamping mechanism 302 through metal indium to form good heat conductivity, a second cooling water pipe 305 is communicated between the second cooling clamping mechanism 302 to cool the second attenuation piece 301, and a water inlet and a water outlet of the second cooling water pipe 305 are located at the top end of the second cooling clamping mechanism 302. The part of the second cooling and clamping mechanism 302, which is positioned outside the vacuum cavity 4, is sleeved with a second corrugated pipe 303 for separating a second right-angle trapezoidal attenuation sheet 301 working in the vacuum cavity 4 from a second motion driving mechanism 306 working in the atmosphere, so that the second attenuation sheet 301 is always positioned in the vacuum cavity 4 during motion.

The first attenuation sheet 21 and the second attenuation sheet 301 are both right-angle trapezoids, the two right-angle trapezoids are the same in shape and size, one end, where the longer bottom edge of the first attenuation sheet 21 is located, is connected with the first cooling clamping mechanism 203, one end, where the longer bottom edge of the second attenuation sheet 301 is located, is connected with the second cooling clamping mechanism 302, the inclined edge of the first attenuation sheet 21 and the inclined edge of the second attenuation sheet 301 are oppositely arranged in the vacuum cavity 4, the thicknesses formed in the optical path are complementary, it is guaranteed that the parts of the two attenuation sheets in the X-ray free electron laser beam 1 are the same in thickness, and the right-angle edge of the first attenuation sheet 21 is a light.

The vacuum chamber 4 is used for installing the front attenuation arm 2 and the rear attenuation arm 3, so that the first attenuation sheet 21 of the front attenuation arm 2, the part of the cooling clamping mechanism one 203 connected with the first attenuation sheet 21, the second attenuation sheet 301 of the rear attenuation arm 3 and the part of the cooling clamping mechanism two 302 connected with the second attenuation sheet 301 work under the vacuum condition.

The motion control mechanism 5 is used to control the first motion drive mechanism 207 of the front damping arm 2 and the second motion drive mechanism 306 of the rear damping arm 3.

The control computer system 6 is used for calculating the movement distance of the first movement driving mechanism 207 and the second movement driving mechanism 306 according to the attenuation requirement and sending a control command to the movement control mechanism 5.

Based on the solid attenuator, as shown in fig. 7, the attenuation control method of the hard X-ray free electron laser of the present invention includes the following steps:

s1: calculating linear absorption coefficients of the diamond and the monocrystalline silicon or the boron carbide under different energies by using X-ray calculation software XOP/xCrossSec;

s2: forming an interpolation function between the linear absorption coefficients and energy of the diamond and the monocrystalline silicon or the boron carbide according to the data calculated in S1, and calculating the linear absorption coefficient mu 1 of the diamond sheet and the linear absorption coefficient mu 2 of the monocrystalline silicon or the boron carbide according to the energy when attenuation is needed;

s3: assuming that the attenuation coefficient of a diamond portion with a thickness of t1 is a1, the attenuation coefficient of a monocrystalline silicon or boron carbide portion with a thickness of t2 is a2, the required attenuation coefficient is a0, the thickness of t1 is generally about 10-200 micrometers, a0 is a1 is a1, and the formula of the attenuation coefficient is defined as a ═ e^-μtCalculating the thickness t2 of the needed monocrystalline silicon or boron carbide when the thickness t1 of the diamond is calculated,

s4: setting the included angle between the right-angle side and the oblique side of the attenuation sheet I and the attenuation sheet II as theta, calculating the movement distance X of the front attenuation arm and the rear attenuation arm according to the geometric parameters of the attenuation sheet I and the attenuation sheet II and the point 0 which is the superposition position of the shorter bottom sides of the right-angle trapezoidal attenuation sheet I and the attenuation sheet II and the optical axis of the X-ray free electron laser,

s5: and the control computer system sends a control instruction to the motion control system according to the calculation result to simultaneously move the front attenuation arm and the rear attenuation arm by the x distance.

S4 may also be set to control only the movement of the front or rear damping arms, and the current positions of both damping arms are x0, and the movement distance x1 needs to be controlled as follows:

and the control computer system sends a control command to the motion control system according to the calculation result to move the front damping arm or the rear damping arm by x1 distance.