阅读说明：本技术 一种基于离子束高次电离原理的x射线光束位置探测器 (X-ray beam position detector based on high-order ionization principle of ion beam ) 是由 张小威 杨福桂 石泓 于 2021-09-22 设计创作，主要内容包括：本发明涉及一种基于离子束高次电离原理的X射线光束位置探测器,包括：离子源、离子加速电极、电磁透镜、扫描器件、待测X射线光束、耦合透镜、离子价态分析器、时间分辨监测控制及数据采集-处理系统；所述离子源连接到离子加速电极,所述离子电极用于提供几百eV–keV的电极电压；所述离子加速电极后面设置有电磁透镜,用于聚焦被离子加速电极加速后的离子束,提高空间分辨率并且分离出低价离子；所述电磁透镜后面设置有离子束的扫描器件；通过扫描器件后的离子束扫描照射到待测X射线光束,用于对X射线光束进行扫描；通过待测X射线光束之后的离子束被输入到离子价态分析器,用于分离扫描过X射线光束的被高次电离的离子。(The invention relates to an X-ray beam position detector based on the high-order ionization principle of an ion beam, which comprises: the device comprises an ion source, an ion accelerating electrode, an electromagnetic lens, a scanning device, an X-ray beam to be detected, a coupling lens, an ion valence state analyzer and a time-resolved monitoring control and data acquisition-processing system; the ion source is connected to an ion accelerating electrode for providing an electrode voltage of several hundred eV-keV; an electromagnetic lens is arranged behind the ion accelerating electrode and used for focusing the ion beam accelerated by the ion accelerating electrode, improving the spatial resolution and separating low-valence ions; a scanning device of ion beams is arranged behind the electromagnetic lens; the ion beam after passing through the scanning device is scanned and irradiated to an X-ray beam to be detected and is used for scanning the X-ray beam; the ion beam after passing through the X-ray beam to be measured is input to an ion valence analyzer for separating the high-order ionized ions scanned through the X-ray beam.)

1. An X-ray beam position detector based on the principle of higher order ionization of an ion beam, comprising: the device comprises an ion source, an ion accelerating electrode, an electromagnetic lens, a scanning device, an X-ray beam to be detected, a coupling lens, an ion valence state analyzer and a data acquisition-processing system for time-resolved detection.

The ion source for providing an ion beam, the ion source being connected to an ion accelerating electrode for providing an electrode voltage of several hundred eV-several keV;

an electromagnetic lens is arranged behind the ion accelerating electrode and used for focusing the ion beam accelerated by the accelerating electrode, improving the spatial resolution and separating low-valence ions;

a scanning device of the ion beam is arranged behind the electromagnetic lens and is used for controlling the ion beam to scan a light beam, an electric field or a magnetic field; the beam passing through the scanning device irradiates an X-ray beam to be detected and is used for scanning the X-ray beam;

the ion beam passing through the X-ray beam to be detected is input to an ion valence state analyzer for separating ions which are scanned by the X-ray beam and ionized by high order;

and the time-resolved monitoring control and data acquisition-processing system is used for acquiring and processing data of the ion beam.

2. The X-ray beam position detector based on the high-order ionization principle of the ion beam as claimed in claim 1, further comprising a vacuum chamber for providing a vacuum environment, wherein the above components are located in the vacuum chamber;

the ion source generates ions, and the ions are accelerated by the ion accelerating electrode to form an ion beam; after the electromagnetic lens focuses the ion beam to the size of a target beam spot, the X-ray beam to be detected is scanned under the control of the scanning device.

3. An X-ray beam position detector based on the principle of higher order ionization of ion beams as claimed in claim 1,

when the ion beam scans the cross section of the X-ray beam and passes through the strong light region, ions in the ion beam are ionized again by the X-ray beam to generate high-price ions; higher valence ions in the ion beam can be separated from monovalent ions by a valence analyzer; the intensity of the divalent ions in the high valence ions is in direct proportion to the intensity of the X-ray, so that the distribution information of the beam cross section is obtained; the ion beam which is scanned by the X-ray beam and contains univalent ions and high-valent ions is collected by the coupling lens, the transverse scanning of the X-ray beam by the ion beam is realized through the time-resolved signal detection and data acquisition-processing system, and the two-dimensional intensity distribution of the detected X-ray beam is detected and analyzed.

4. An X-ray beam position detector based on the principle of higher order ionization of ion beams as claimed in claim 1,

the scanning device adopts electric field control or magnetic field control; and two-dimensional detection is realized by respectively configuring one scanner in the vertical direction and the horizontal direction, and two-dimensional information is given.

5. An X-ray beam position detector based on the principle of higher order ionization of ion beams as claimed in claim 1,

the ion valence state analyzer comprises a mass spectrometer and an ion detection system; the mass spectrometer is of an electrostatic type or a magnetic field type, and adopts a sector structure or a four-electrode structure.

6. An X-ray beam position detector based on the principle of higher order ionization of ion beams as claimed in claim 5,

the ion detector of the ion detection system is a secondary electron multiplier, ions are multiplied step by step and finally enter the recording and observing system, and the recording and observing system is recorded by a recorder and a counter.

7. An X-ray beam position detector based on the principle of higher order ionization of ion beams as claimed in claim 1,

the data acquisition-processing system for time-resolved detection comprises two functions, one is used for controlling the synchronization of data acquisition and an ion beam scanning device, namely the secondary ion signal intensity of a detector and an ion beam scanning position signal, namely the sequential scanning measurement is realized.

Technical Field

The invention provides a detection method for the position of an X-ray beam with high intensity/power density, which solves the problem that the existing position detector cannot bear high thermal load and high background noise.

Background

With the development of scientific research, the demand of high-intensity X-ray light source devices such as free electron laser, synchrotron radiation light source and other large scientific devices has become more and more strong in recent years. The X-ray beam position detector is a key component of the beam line in synchrotron radiation apparatus, and it provides real-time data on the position/angle, distribution and intensity of the beam, and is the basic information for monitoring the light source and beam line operating conditions, and for adjusting the line station optics.

Conventional beam position detection devices include fluorescent targets, diamond electrodes, wire scanning, ionization chambers, and the like.

(1) The fluorescent screen is designed to convert X-rays into visible light using a fluorescent material or the like, and the distribution and position of the X-ray beam can be estimated by observing the light intensity distribution on the recording fluorescent material with an image sensor.

(2) In the diamond four-quadrant detector, current signals are obtained by utilizing the relative position relationship between two groups of symmetrical electrodes which are provided with certain bias voltage and X-ray beams. When the X-ray beam enters the sensitive region of the detector, its ionization causes a certain number of electron-hole pairs to be generated in the electrodes. The electrons and the holes move to the two groups of electrode ends respectively under the action of the electric field to form current. The position of the center of gravity of the incident beam can be determined based on the ratio of the difference between the current values collected at the two ends of the same electrode to the total current value.

(3) In the wire scanning scheme, when a cross scanning wire made of a special material scans an X-ray beam, a photoelectric effect is generated to form a photocurrent. The signal intensity of the photocurrent is in direct proportion to the intensity of the X-ray beam, and the gravity center position and the cross section of the beam can be calculated after the signal intensity is amplified by an electronic instrument. Wire scanning may affect user light usage during the measurement process.

(4) In the scheme of the ionization chamber, gas is used as a detection medium, and an anode plate of the ionization chamber is loaded with positive voltage. After the gas is ionized, electrons/positive ions are collected by the anode/cathode. By dividing the electrode plate, such as making the electrode in a zigzag shape as shown in fig. 1, the ionization signal generated when the X-ray beam passes through different regions can be represented on the difference of the electrode signal, thereby obtaining the position information of the beam.

The general problems of the above detection methods include several problems: (1) destructive beam transmission, such as diamond four quadrant, wire scanning; (2) cannot bear the high heat load of the radiation of the undulator, even be damaged, and particularly for high-energy light sources, the power density on the optical axis is very high; (3) the spatial distribution of the undulator radiation changes along with the adjustment of the gap parameter of the undulator, and the central position of the undulator radiation cannot be accurately measured only by the radiation signals at the periphery due to the background influence of the peripheral bent iron radiation.

Disclosure of Invention

In order to solve the technical problems, the invention provides a novel method for detecting the position of an X-ray beam which generates high-order ionization based on the interaction between an ion beam and the X-ray beam, namely, the detection of the cross section intensity of the X-ray beam is realized based on a monovalent ion beam, in order to not damage the X-ray beam and not be damaged by the X-ray beam. In addition, in order to realize the measurement of the cross section of the light beam, the invention uses the mode that the ion beam scans the light beam transversely. Finally, since the ion beam is free of cooling problems and is used in a vacuum, it is suitable for use on high intensity synchrotron radiation beams and can achieve very good signal-to-noise ratios.

The technical scheme of the invention is as follows: an X-ray beam position detector based on the principle of higher order ionization of an ion beam, comprising: the device comprises an ion source, an ion accelerating electrode, an electromagnetic lens, a scanning device, an X-ray beam to be detected, a coupling lens, an ion valence state analyzer and a data acquisition-processing system for time-resolved detection.

The ion source for providing an ion beam, the ion source being connected to an ion accelerating electrode for providing an electrode voltage of several hundred eV to several keV;

an electromagnetic lens is arranged behind the ion accelerating electrode and used for focusing the ion beam accelerated by the ion accelerating electrode, improving the spatial resolution and separating low-valence ions;

a scanning device of the ion beam is arranged behind the electromagnetic lens and is used for controlling the ion beam to scan a light beam, an electric field or a magnetic field; the beam passing through the scanning device irradiates an X-ray beam to be detected and is used for scanning the X-ray beam;

the ion beam passing through the X-ray beam to be detected is input to an ion valence state analyzer for separating ions which are scanned by the X-ray beam and ionized by high order;

the time resolution monitoring control and data acquisition-processing system is used for acquiring and processing data of the ion beam;

the vacuum chamber is used for providing a vacuum environment, and all the components are positioned in the vacuum chamber;

the ion source generates ions, and the ions are accelerated by the ion accelerating electrode to form an ion beam; after the electromagnetic lens focuses the ion beam to the size of a target beam spot, the X-ray beam to be detected is scanned under the control of the scanning device.

Furthermore, when the ion beam scans the cross section of the X-ray beam and passes through the strong light region, the ion beam is ionized again by the X-ray beam to generate high-price ions; higher valence ions in the ion beam can be separated from monovalent ions by a valence analyzer; the intensity of the divalent ions in the high valence ions is in direct proportion to the intensity of the X-ray, so that the distribution information of the beam cross section is obtained; the ion beam containing univalent ions and high-valence ions is collected by a coupling lens, the transverse scanning of the ion beam on the X-ray beam is realized by a time-resolved monitoring control and data acquisition-processing system, and the two-dimensional intensity distribution of the detected X-ray beam is detected and analyzed.

Furthermore, the scanning device adopts electric field control or magnetic field control; and two-dimensional detection is realized by respectively configuring one scanner in the vertical direction and the horizontal direction, and two-dimensional information is given.

The ion valence state analyzer comprises a mass spectrometer and an ion detection system; the mass spectrometer is of an electrostatic type or a magnetic field type, and adopts a sector structure or a four-electrode structure.

Furthermore, as for a mass spectrometer with a sector structure, a sector electric field and a sector magnetic field are arranged in the mass spectrometer; the secondary ions first enter a fan-shaped electric field through an entrance slit through a field aperture, called an electrostatic analyzer; in the sector electric field, ions move along a circular orbit with radius r, and the force generated by the sector electric field is equal to the centripetal force; changing the width of the energy slit, and selecting secondary ions with different energies to enter the fan-shaped magnetic field through the lens of the spectrometer; the secondary ions deflected by the electric field enter the fan-shaped magnetic field again for secondary focusing, and the ions with different mass-to-charge ratios are focused on different points of an imaging surface; if the exit slit is stationary, the intensity of the magnetic sector is adjusted so that only the target ions enter the ion detector through the exit slit.

Furthermore, an ion detector of the ion detection system is a secondary electron multiplier, secondary ions pass through an outlet slit of a mass spectrometer and then pass through a projection lens to reach another electrostatic field, wherein one part of the secondary ions directly reach an imaging detector, and the other part of the secondary ions directly collide with a primary electrode of the electron multiplier through a Faraday cup after passing through an ion beam diverter to generate secondary electron emission; the secondary electrons are attracted and accelerated by the second-stage electrode, more secondary electrons are bombed on the secondary electrons, and the secondary electrons are multiplied step by step and finally enter a recording and observing system and are recorded by a recorder and a counter.

Furthermore, the data acquisition-processing system for time-resolved detection comprises two functions, one is used for controlling the synchronization of data acquisition and the scanning device of the ion beam, namely the secondary ion signal intensity of the detector and the ion beam scanning position signal, namely the sequential scanning measurement is realized.

Has the advantages that:

the invention has scientific and reasonable design, can realize the direct measurement of the strong X-ray beam and give the position information of the measured X-ray beam on the premise of not destroying the user experiment (namely the beam quality) of the beam line.

Drawings

FIG. 1 is a schematic diagram of a prior art ionization chamber arrangement;

FIG. 2 is a schematic block diagram of an X-ray beam position detector based on the high-order ionization principle of an ion beam according to the present invention;

FIG. 3 is a schematic diagram of an ion valence analyzer;

figure 4 is a schematic diagram of an ion detection system.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments, and all other embodiments obtained by a person skilled in the art based on the embodiments of the present invention belong to the protection scope of the present invention without creative efforts.

According to an embodiment of the present invention, there is provided an X-ray beam position detector based on the principle of higher order ionization of an ion beam, as shown in fig. 2, including: the device comprises an ion source 1, an ion accelerating electrode 2, an electromagnetic lens 3, a scanning device 4, an X-ray beam 5 to be detected, a coupling lens 6, an ion valence state analyzer 7 and a time-resolved monitoring control and data acquisition-processing system 8.

The ion source 1 for providing an ion beam, such as monovalent ions like Mg +, Ca +; the ion source 1 is connected to an ion acceleration electrode 2, the ion acceleration electrode 2 being for providing an electrode voltage of several hundred eV-several keV; the number k and the amount V are 2 to 9keV, such as 8keV, which can be adjusted according to the situation, but the invention is not limited;

an electromagnetic lens 3 is arranged behind the ion accelerating electrode 2 and used for focusing the ion beam 10 accelerated by the ion accelerating electrode, improving the spatial resolution and separating low-price ions;

a scanning device 4 of ion beams is arranged behind the electromagnetic lens 3 and is used for controlling the ion beams to scan light beams, electric fields or magnetic fields; the beam passing through the scanning device 4 irradiates the X-ray beam 5 to be detected for scanning the X-ray beam 5;

the ion beam after passing through the X-ray beam 5 to be measured is inputted to an ion valence state analyzer 7 for separating the ions ionized by a high order scanned by the X-ray beam;

and the time-resolved monitoring control and data acquisition-processing system 8 is used for acquiring and processing data of the ion beam.

The vacuum chamber is used for providing a vacuum environment, and all the components are positioned in the vacuum chamber.

Referring to fig. 2, an ion source 1 generates ions and is accelerated by an ion accelerating electrode 2 to form an ion beam 10; the electromagnetic lens focuses 3 the ion beam to a target beam spot size (e.g., micron size), and then scans the X-ray beam 5 under control of the scanning device 4.

When the ion beam 10 scans the cross section of the X-ray beam 5 and the ion beam 10 passes through an intense light region, the ion beam is ionized again by the X-ray beam, and expensive ions are generated. Higher valent ions in the ion beam can be separated from monovalent ions using a valence analyzer. The intensity of the divalent ions in the high valence ions is proportional to the intensity of the X-ray, so that the distribution information of the beam cross section can be obtained. The ion beam 11 containing univalent ions and high-valence ions is collected by the coupling lens 6, the transverse scanning of the ion beam to the X-ray beam is realized by the time-resolved monitoring control and data acquisition-processing system 8, and the two-dimensional intensity distribution of the detected X-ray beam is detected and analyzed. The whole experimental system needs to be built in a vacuum cavity.

The scanning device 4 according to the embodiment of the present invention may be either electric field controlled or magnetic field controlled.

Optionally, two-dimensional detection can be realized by configuring one scanner in each of the vertical and horizontal directions, and two-dimensional information is given;

according to an embodiment of the present invention, referring to fig. 3, the ion valence analyzer 7 includes two parts, namely a mass spectrometer and an ion detection system. The mass spectrometer consists of a sector electric field and a sector magnetic field (as shown in figure 3). The secondary ions first enter a fan-shaped electric field 23, called an electrostatic analyzer, through the entrance slit 21 through the field aperture 22. Within the sector electric field, the ions follow a circular trajectory with radius r, the force generated by the sector electric field being equal to the centripetal force. In fig. 3, the energy slit 24 is provided, and the secondary ions with different energies can be selected by changing the width of the energy slit 24 to enter the magnetic field through the spectrometer lens 25. The secondary ions deflected by the electric field then enter the magnetic sector field 26 (magnetic analyzer) for secondary focusing, and ions with different mass-to-charge ratios are focused on different points of the imaging surface. If the exit slit 27 is stationary, the strength of the magnetic sector is adjusted so that only the target ions enter the ion detector through the exit slit 27.

As shown in fig. 3 and 4, the ion detector of the ion detection system is a secondary electron multiplier, and the secondary ions pass through the exit slit 27 of the mass spectrometer, pass through the projection lens 32, and reach another electrostatic field 34, one part of which directly reaches the imaging detector 35, and the other part of which directly collides with the primary electrode of the electron multiplier 37 through the faraday cup 36 after passing through the ion beam deflector 33, so as to generate secondary electron emission. The secondary electrons are attracted and accelerated by the second stage electrode, whereupon more secondary electrons are bombarded, thus multiplying step by step, and finally enter the recording and viewing system, recorded by the recorder 38 and the counter 39.

According to an embodiment of the present invention, the time-resolved monitoring control and data acquisition-processing system 8 includes two functions, one is for controlling the synchronization of data acquisition and the scanning device 4 of the ion beam, i.e. the secondary ion signal intensity of the detector and the ion beam scanning position signal, i.e. implementing sequential scanning measurement.

The other part is data acquisition, processing and display, and gives complete light beam information. According to the change curve of the scanning position and the recorded light intensity, the following steps can be carried out: (1) searching the position of the maximum light intensity value point, and determining the center of the light beam; (2) the width of the beam is determined according to the width of the curve.

Although illustrative embodiments of the present invention have been described above to facilitate the understanding of the present invention by those skilled in the art, it should be understood that the present invention is not limited to the scope of the embodiments, but various changes may be apparent to those skilled in the art, and it is intended that all inventive concepts utilizing the inventive concepts set forth herein be protected without departing from the spirit and scope of the present invention as defined and limited by the appended claims.