KR102123965B1 - Charged Particle Measurement Apparatus - Google Patents

Abstract

While simultaneously measuring a low-power charged particle beam and a high-power charged particle beam with a single device, it is possible to easily measure and pass the beam by rotation of the ring member, and even when a high energy incident beam collides, neutron emission is suppressed and radiation is suppressed. The Faraday cup assembly has the advantage of being easy to implement and effectively measuring the size of the incident charged particle beam by including a particle receiving target made of graphite material that is not only advantageous for safety management, but also minimizes damage by the high-power charged particle beam. It relates to a charged particle beam current measuring device comprising a.

Description

Charged Particle Measurement Apparatus

One embodiment according to the present invention relates to a current of charged particles, that is, the number of particles, a measuring device. More specifically, the present invention relates to a charged particle current measuring device that stably measures a high-energy large-current ion or proton beam by constructing one surface of a Faraday Cup through which charged particle beams are made of graphite.

The contents described below merely provide background information related to an embodiment according to the present invention, and do not constitute a prior art.

Charged Particles with charges such as Electron, Proton, Ion, and Deuteron accelerate to have proper kinetic energy and are used for material processing, material analysis, and nuclear reaction induction. do. These charged particles are generated from the plasma of the constituent components, and then applied to an electric field to process them in the form of a beam through a process such as particle acceleration.

Charged Particle Beam is a device used in various nano structures and semiconductor manufacturing processes such as etching, doping, and ion implantation, proton treatment, neutron treatment, and boron neutron capture treatment ( It is mainly used for particle beam treatment devices such as BNCT (Boron Neutron Capture Therapy) facilities.

Since the characteristics of the beam current of the charged particle beam device change with time, it is necessary to periodically measure and adjust the current of the charged particle beam in order to transport the desired amount of particle beam. For this, it is generally necessary to measure the amount of charged particles by measuring the current by placing a suitable ion beam current measuring device during a beam suit.

The device most commonly used to measure charged particle current is the Faraday Cup. Typically, the Faraday cup is formed of a metallic material that is a conductor to prevent space charge, and has an opening on the top surface and a closed cup shape on the side and bottom, so that once collected, the collected charged particles do not escape. It is a structure.

The measurement of the current is made by detecting the amount of current delivered when the charged particle beam incident into the Faraday cup touches the conductive cup. The Faraday cup detects the amount of current over a unit of time, which is useful for measuring the current of a charged particle beam with continuous or pulsed current operation.

The Faraday Cup is located at a point on the transport path of the beam that connects the final destination, the target, from the ion source where the charged particle beam is generated, while blocking the transport path of the beam, charged particles per unit time Measure the number. When the current is measured, the Faraday cup is placed out of the beam's traveling path so as not to interfere with the transport of the ion beam.

In the case of a conventional particle beam current measuring device, the measurement is performed while moving the position of the cup horizontally and vertically during measurement. This repetitive mechanical movement is not only complicated in the configuration of the Faraday Cup Assembly, but can also cause wear or defects. In addition, fine dust generated due to wear or defects and vacuum leakage may occur in a vacuum chamber including a Faraday cup assembly.

On the other hand, when a high energy proton charged particle beam of several MeV or more is incident on the Faraday cup, the charged particle beam may cause nuclear reaction with the nuclear nucleus of the colliding material to cause radiation generation, and outgassing emitted from the Faraday target material Due to this, the pressure of the beam transport system increases, and the vacuum degree may decrease.

Accordingly, there is a need for a device capable of accurately measuring the ion beam current over a wide range of beam output ranges from high energy, high current, that is, high power beam, while simplifying the configuration of the vacuum box including the Faraday cup assembly.

According to an embodiment of the present invention, an object of the present invention is to provide a charged particle current measuring device capable of performing rapid beam current measurement by a Faraday cup while simplifying the configuration of a vacuum box and ensuring durability. In particular, it is an object to provide a charged particle beam current measuring device capable of measuring a charged particle beam current in a high energy range of several MeV or more and a high power range of several tens of kW or more.

In addition, according to an embodiment of the present invention, it is an object to provide a charged particle beam current measuring device that can be easily configured at low cost.

Charged particle beam current measuring apparatus according to an embodiment of the present invention, a vacuum box disposed on the transport path of the charged particle beam (Charged Particle Beam); And a Faraday Cup Assembly having a rotation axis perpendicular to the transport path in the vacuum box, wherein the Faraday Cup assembly comprises: a ring member disposed about an intersection of the transport path and the rotation axis; It is disposed on a bonding surface that is a plane formed on one side of the circumferential surface of the ring member, the plane is a first collection portion parallel to the plane including the central axis and the rotation axis of the ring member; A second collection part disposed between the inlet and the ring member of the vacuum box to which the charged particle beam is incident, and in the form of a cylinder surrounding the transport path; And a third collecting unit including a cooling channel formed inside the rotating shaft and the ring member, and a calorific sensor for measuring the amount of heat flowing into the cooling channel by the charged particle beam incident on the first collecting unit, and the center of the ring member. When the ring member is rotated to the first position along the transport path along the axis, the charged particle beam passes through, and when the ring member is rotated to the second position where the charged particle beam is vertically incident to the first collector, the first collector And the incident amount of the charged particle beam is measured by the second collecting portion, and the first collecting portion is made of graphite.

In addition, the first collection unit is characterized in that it is bonded to the bonding surface by brazing (brazing) to ensure the high vacuum and ease of assembly of the transport system.

In addition, the bonding layer between the first collecting portion and the bonding surface by blazing is characterized in that it comprises a silver paste (silver paste) to favor heat transfer.

In addition, the bonding surface is characterized in that the bottom surface of the pocket portion formed so that at least a portion of the side surface of the first collection portion and the inner wall are joined.

In addition, the thickness of the first collecting portion is characterized in that it is formed so as to exceed the penetration depth of the charged particle beam to the first collecting portion.

According to an embodiment of the present invention, a beam measurement is performed only by a simple rotating operation of the Faraday cup, thereby reducing measurement time and increasing durability of the measurement system. In addition, by constructing the surface where the charged particle beam is incident with graphite material, neutron emission due to incident beam collision is small, and high-temperature heat generated by the incident of the large current beam can be transferred to cool, and radiation caused by collision of the beam can be minimized. In addition, there is an effect of minimizing the reduction in the vacuum degree of the vacuum box.

1 is a view showing a Faraday cup assembly included in a particle measuring apparatus according to an embodiment of the present invention.
2 is a result of analyzing the threshold energy of neutron generation due to proton collision of Cu-63 and Cu-65 isotopes.
3 is a result of analyzing the threshold energy of neutron generation due to proton collision of C-12 among the isotopes of graphite.
4 shows the structure of the first collection unit in two forms according to an embodiment of the present invention.
5 shows the contents of interpreting the penetration depth according to proton energy as a computer simulation.
Figure 6 shows the results of analyzing the depth of penetration into the graphite material according to the proton energy by computer simulation.
7 is a photograph showing a particle measuring device according to an embodiment of the present invention.
8 is a photograph showing a first collection unit of a particle measurement device manufactured according to an embodiment of the present invention.
9 is a detailed photo showing a first collection unit of the particle measurement device manufactured according to an embodiment of the present invention.
10 is a view showing an environment for measuring current using a particle measuring device according to an embodiment of the present invention.
11 illustrates a Faraday cup assembly when blocking a charged particle beam using a particle measuring device according to an embodiment of the present invention.
12 shows a Faraday cup assembly when passing a charged particle beam using a particle measuring device according to an embodiment of the present invention.
13 is a configuration diagram for remotely controlling the Faraday cup assembly of the particle measuring apparatus according to an embodiment of the present invention.
14 is a conceptual diagram illustrating a secondary electron suppression unit of a particle measurement device according to an embodiment of the present invention.
15 is a detailed photo of the secondary electron suppression unit side of the particle measurement device manufactured according to an embodiment of the present invention.
16 illustrates an environment for measuring calories in a particle measuring device according to an embodiment of the present invention.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that, when adding reference numerals to the components of each drawing, the same components have the same reference numerals as possible, even if they are displayed on different drawings. In addition, in describing one embodiment of the present invention, when it is determined that a detailed description of a related known configuration or function may obscure the gist of an embodiment of the present invention, the detailed description thereof will be omitted.

In describing the components of the embodiment according to the present invention, first, second, iii), ii), a), b), etc. may be used. These symbols are only for distinguishing the components from other components, and the nature, order, or order of the components is not limited by the symbols. Also, when a part in the specification refers to'include' or'equipment' a component, it means that other components may be further included rather than excluding other components, unless explicitly stated to the contrary. do.

Hereinafter, a particle measuring apparatus according to an embodiment of the present invention will be described with reference to the accompanying drawings.

1 is a view showing a Faraday cup assembly included in a particle measuring apparatus according to an embodiment of the present invention.

Figure 1 (a) is a Faraday Cup Assembly according to an embodiment (100, Faraday Cup Assembly) shows the appearance of a vacuum box, Figure 1 (b) is a cross-sectional view of Figure 1 (a), in one embodiment The structure of the Faraday cup assembly 100 is shown.

The Faraday cup assembly 100 according to an embodiment is characterized in that the ring-shaped ring member 102 disposed on the path of the charged particle beam is rotated and arranged to pass or block the beam. When arranged to block the beam, the amount of incidence per unit time of the charged particle beam is measured, and when arranged to pass the beam, the incident charged particle beam passes through the Faraday cup assembly 100.

The Faraday cup assembly 100 includes a flange 101, a ring member 102, a first collecting portion 102-A, a rotating shaft 103, an insulator 104, an O-ring 105, and an O-ring. Part 106, Suppression Magnet 107, Secondary Electron Suppression Unit 108, Housing 109, Housing, Injection 103-A and Discharge 103-B It includes.

The ring member 102 is a hole portion in the center of the ring formed to pass the beam, a portion connected to the rotating shaft 103, parallel to the direction of the rotating shaft 103, perpendicular to the central axis of the hole portion, and the outer peripheral surface of the ring member 102 A cooling passage formed to cool at least one bonding surface and a bonding surface formed in a flat shape, and formed to be in fluid communication with the injection part 103-A and the discharge part 103-B through the inside of the rotating shaft 103. Includes.

The ring member 102 is configured to be connected to the rotating shaft 103 so that the arrangement position can be rotated by rotating the rotating shaft 103. The ring member 102 and the rotating shaft 103 may be integrally formed. The ring member 102 passes through the charged particle beam when it is rotated so that the central axis of the hole portion lies in parallel with the transport direction of the charged particle beam. The first collection portion 102-A may be joined to at least one bonding surface by brazing. When the bonding surface of the ring member 102, that is, the first collecting portion 102-A is rotated and disposed to be perpendicular to the incident charged particle beam, the charged particle beam collides and absorbs the first collecting portion 102-A Or is reflected. The first collecting part 102-A, the ring member 102 and the rotating shaft 103 are used to transfer the current from the charged particle beam incident on the first collecting part 102-A to the measurement system outside the vacuum chamber. It is made of an electrically conductive material. In addition, the first collector 102-A, the ring member 102 and the rotating shaft 103 are preferably a material having high thermal conductivity to effectively transfer and cool heat generated by the charged particle beam incident with a large current. In one embodiment, the ring member 102 and the rotating shaft 103 may be made of a copper or aluminum material having excellent electrical and thermal conductivity properties. Considering the gas discharge of the material, it is preferable that it is copper. On the other hand, the first collection unit 102-A in which the charged particle beam directly collides must have less damage due to collision of particles and outgassing due to the collision.

In consideration of these matters, the first collecting part 102-A according to an embodiment of the present invention uses a plate-shaped member made of graphite, and is attached to the bonding surface of the ring member 102 by blazing. To join. The blazing layer that bonds the back surface of the first collector portion 102-A, which is a graphite material, and the bonding surface, which is a copper material, may include a silver paste to increase heat transfer efficiency.

In a conventional particle current measuring device, the member to which the charged particle beam is incident is made of copper. The compositional isotope ratio of copper occupies most of Cu-63 (69.15%) having an atomic mass of 63 and Cu-65 (30.85%) of 65. Referring to FIG. 2, the threshold energy of neutron generation due to proton collision of the Cu-63 and Cu-65 isotopes is 4.22 MeV and 2.17 MeV, respectively, and the cross-sectional area of the neutron generation reaction for 10 MeV proton collision is 345 mb (milli -Barn), 0.708 mb. This means that if the beam current of a high-power proton accelerator is directly measured, there is a fear of emitting a large amount of neutrons. In addition, the generated neutron reacts with copper and housing material (eg, SUS-304, etc.), which are components of the existing measuring device, to generate secondary radionuclides. Residual radioactivity of the radioactive measuring device may increase the exposure of workers during attenuation even after stopping the operation of the accelerator, and for long-term use, additional shielding and consideration as radioactive waste may be necessary.

On the other hand, referring to Figure 3, C-12 of the isotopes of graphite has a threshold energy of (p, n) nuclear reaction of about 19 MeV. The high threshold energy of such graphite means that even when a high-power proton beam of 10 MeV, for example, of a commercial high-power ion accelerator is incident, no neutrons are generated due to such collision energy, and thus secondary radioactive isotopes are not generated. Does not. Among the isotopes of graphite, C-13 has a cross-sectional area of 3.24 MeV (p, n) nuclear reaction, and produces C-14 as a secondary radioactive isotope by neutrons. However, this amount can be neglected because C-13 has a very small percentage of natural presence (1.11%) and a reaction area of C-14 production in the order of tens of micro barns. Therefore, in the first collector portion 102-A made of a graphite material according to an embodiment of the present invention, neutron emission is suppressed even when a high energy incident beam collides, compared to a case of a normal copper material, and the device Since the issue of radiation is reduced, it may be easy to secure radiation stability. That is, in one embodiment of the present invention, by using a graphite material, it is possible to facilitate the response of the radiation safety management aspect in an environment in which a high energy beam is used because the threshold energy of neutron generation against proton collision is high.

On the other hand, the graphite material has a very high thermal conductivity and electrical conductivity as well as a very high hardness and melting viscosity, and is very suitable as a material that absorbs beam energy of an incident large current and transmits current by the charged particles. In particular, the graphite material has a very low efficiency of brakingstrahlung production compared to other metal materials. That is, the generation of various types of electromagnetic radiation such as X-rays, which is incident to and radiated to the outside by particles that collide with the first collector 102-A, may be low. For this reason, it is also used for shielding high energy beams, such as the reactor's shield wall.

The present invention is characterized in that a measuring system suitable for a large current beam is constructed by allowing a charged particle beam having a number of MeV or more to enter the graphite material. Assuming a case in which a common copper material is used for the first collector portion 102-A, the surface is damaged by frequent large current beam incidence, and the mechanical surface is further deteriorated by heating the incident surface at a high temperature, and a high energy beam Contamination of the vacuum line increases due to the large amount of particles emitted by the collision, and consequently, the operation of the equipment may be difficult due to a decrease in vacuum. On the other hand, graphite material has the advantage of absorbing the incident beam, the strength at high temperature is very high, and the ability to transfer the generated heat to the outside is very excellent. Suitable.

delete

On the other hand, graphite has different thermal conductivity in the planar direction and the thickness direction depending on the manufacturing method or the manufactured state, but in most cases, it has a greater thermal conductivity than copper or aluminum. The primary direction in which crystals are grown and connected is a high thermal conductivity in the planar direction, for example, usually at a level of 370 W/m·K, and in the case of HOPG (Highly oriented pyrolytic graphite), 1700 W/m· in the planar direction. It may also have a thermal conductivity of K. However, in most cases, the thermal conductivity in the thickness direction is generally lower than the plane direction.

4 shows the structure of the first collection unit in two forms according to an embodiment of the present invention.

Referring to FIG. 4(a), the first collection portion 102-A may be directly bonded to a joint formed flat on the side surface of the ring member 102. Referring to FIG. 4(b), the first collection portion The two sides of the portion 102-A may be embodied in a form of being fitted into a portion formed in a pocket shape on the side surface of the ring member 102.

In the case of joining the first collecting portion 102-A in a structure as shown in FIG. 4(b), the bonding surface formed on the side surface of the ring member 102 is at least part of the side surface of the first collecting portion 102-A. It may correspond to the bottom of the pocket portion formed so that the inner wall and the junction. That is, referring to FIG. 4(b), the back surface of the graphite flat plate, which is the first collecting portion 102-A, is blazed using a blazing material containing silver paste, and is bonded to the bottom surface of the pocket portion. Both sides of the collecting section 102-A may be blazed on the side of the pocket portion provided on the ring member 102 using a brazing material containing silver paste. Compared to FIG. 4(a), the embodiment of FIG. 4(b) requires additional processing to form a pocket-shaped junction in the ring member 102, but the ring member 102 generates heat due to the incident charged particle beam. ) And the cooling system connected to the heat transfer efficiency may be increased.

On the other hand, if the graphite material is used in a vacuum, sufficient baking can ensure a sufficient vacuum within the range of the normal vacuum pump capacity. For reference, the outgassing of the baked graphite may be, for example, 5x10 ^-10 mbar·l/s·cm ² .

5 shows the contents of interpreting the penetration depth according to proton energy as a computer simulation.

Figure 6 shows the results of analyzing the depth of penetration into the graphite material according to the proton energy by computer simulation.

5 is a calculation of the depth of penetration according to the proton energy to determine the thickness of the graphite material applied to the first collection unit 102-A according to an embodiment using a Monte Carlo simulation, and for this purpose, ions in the normal material A widely used Stopping and Range of Ions in Materials (SRIM) code was used to calculate process parameters related to implantation and ion irradiation processes.

Referring to FIG. 6, it can be seen that the depth of penetration into the graphite material increases as the proton energy increases, and in one embodiment, operation of a particle beam treatment device such as a boron neutron capture therapy (BNCT) facility In consideration of the conditions and the analysis results of FIG. 6 considering this, the thickness of the graphite sheet was selected as 1 mm. When the analysis results are reviewed, for example, when the proton energy is 11 MeV, and the thickness of the graphite plate material is 0.7 mm, the proton penetrates the graphite and collides with the copper disposed behind the graphite, thereby generating a neutron generation threshold as shown in FIG. 2. Since there is a risk of releasing a large amount of neutrons from low-energy copper, it is desirable to form a thicker graphite plate in consideration of the penetration depth of the charged particle beam.

Referring back to FIG. 1, the flange 101 and the housing 109 include a ring member 102, a rotating shaft 103, an insulator 104, a first collecting portion 102-A, and a second collecting portion 106 It serves to protect and support the components of the back from the outside.

The rotating shaft 103 is connected to both sides of the ring member 102 to rotate the ring member 102. Although not shown, an embodiment in which the rotating shaft 103 is connected to only one side of the ring member 102 is also possible.

The ring member 102 and the first collecting portion 102-A rotate about the rotation shaft 103. In order to secure a space for rotation, it is preferable that the first collection portion 102-A and the second collection portion 106 are spaced apart at predetermined intervals, for example, within an interval of several mm.

The second collecting part 106 is a metal material having excellent conductivity so that it can be reflected after being incident on the first collecting part 102-A and absorb the charge of the charged particle beam incident inside the second collecting part 106, For example, it is formed of copper, stainless steel (SUS) or aluminum.

The charge absorbed by the second collector 106 is counted as the amount of charge per unit time and displayed on the first current value converter or ammeter.

Between the rotating shaft 103 and the vacuum box, an insulating material 104, for example, nylon, is inserted into the outside of the rotating shaft 103 to maintain an electrical insulation state to surround the rotating shaft 103.

On the opposite end of the rotating shaft 103 connected to the ring member 102, a rotating driving unit 530 such as a handle (not shown) or a motor may be installed to rotate the rotating shaft 103 manually or automatically. The rotation angle of the rotating shaft 104 is from 0° to 360°, but an operating range that allows the ring member 102 to pass or block the charged particle beam is substantially 90°.

Since the time taken to rotate the ring member 102 around the rotation axis 103 is much shorter than the time taken to move the ring member 102 in the vertical or horizontal direction, the measurement operation speed for the charged particle beam To improve.

The charged particle beam incident into the Faraday cup assembly 100 may collide with the surface of the first collector portion 102-A or the second collector portion 106 to generate secondary electrons. In order to suppress the secondary electrons, the secondary electron suppression unit 108 and the suppression magnet 107 may be formed near the beam entrance of the Faraday cup assembly 100.

The secondary electron suppressor 108 may be formed in a shape surrounding the inlet of the Faraday cup assembly 100. The secondary electron suppression unit 108 receives electric energy from an external power supply unit, such as a DC external power supply unit, and serves to push the emitted secondary electrons into the second collection unit 106. Here, the magnitude of the voltage applied from the external power supply is 1 kV or more, and the polarity of the voltage is formed to have a negative polarity in order to push electrons with a negative charge. The secondary electron suppression unit 108 may be made of a metal material capable of forming an electromagnetic field by receiving power.

7 is a photograph showing a particle measuring device according to an embodiment of the present invention.

8 is a photograph showing a first collection unit of a particle measurement device manufactured according to an embodiment of the present invention.

9 is a detailed photo showing a first collection unit of the particle measurement device manufactured according to an embodiment of the present invention.

10 is a view showing an environment for measuring current using a particle measuring device according to an embodiment of the present invention.

Referring to FIG. 10, the particle measuring device for measuring the current by counting the charge of the charged particle beam includes a Faraday cup assembly 100 and a Faraday cup assembly 100 electrically connected to the current waveform checking device 210 or current waveform checking It includes a first current value conversion unit having the same function as the device 210.

The electric charge in contact with the second collecting portion 106 is transferred to the ammeter via a conducting wire connected to the second collecting portion 106. The lead wire is connected to the outside of the Faraday cup assembly 100 via the inside of the rotating shaft 103 of the double cylindrical structure.

11 illustrates a Faraday cup assembly when blocking a charged particle beam using a particle measuring device according to an embodiment of the present invention.

11(a) is a side view of the Faraday cup assembly 100, and FIG. 11(b) is a perspective view of the Faraday cup assembly 100.

When measuring the current caused by the charged particle beam, the charged particle beam is blocked at the first position, which is the position where the ring member 102 passes, by operating the rotary drive unit 530 connected to one end of the rotating shaft 103. Rotate to the second position, the position. When the position of the ring member 102 is changed to the second position, the first collection part 102-A provided in the Faraday cup assembly 100 is disposed to be perpendicular to the direction of the charged particle beam, so that the charged particle beam Block progress. Accordingly, the charged particle beam incident into the Faraday cup assembly 100 collides on the surface of the first collector 102-A.

The change of the position of the ring member 102 including the first collecting part 102 -A may be achieved by rotating the ring member 102 by +90° or -90° about the rotation axis 103.

12 shows a Faraday cup assembly when passing a charged particle beam using a particle measuring device according to an embodiment of the present invention.

12(a) is a side view of the Faraday cup assembly 100, and FIG. 12(b) is a perspective perspective view of the Faraday cup assembly 100.

When the measurement of the current caused by the charged particle beam is finished, the position of the ring member 102 is moved from the second position, which is the blocking position, to the first position, which is the passing position, by operating the rotary driving unit 530 connected to one end of the rotating shaft 103. Change to When the position of the ring member 102 is changed from the blocking position to the passing position, the first collection part 102-A existing in the inner space of the Faraday cup assembly 100 is arranged to be parallel to the direction of travel of the charged particle beam. . At the same time, the central axis of the ring member 102 including the first collecting part 102-A is arranged side by side in the traveling path of the charged particle beam so that the charged particle beam passes through the hole portion inside the ring member 102 and then You will proceed to the step.

By changing the position of the ring member 102 to the first position, which is the passing position, it can be seen that the first collecting section 102-A formed on the side surface of the ring member 102 is out of the traveling path of the charged particle beam. . For example, when a particle measuring device according to an embodiment is disposed adjacent to the end of a boron neutron capture therapy (BNCT) facility, the charged particle beam is Faraday with the ring member 102 changed to the first position. The entrance of the cup assembly 100, the second collecting portion 106 and the ring member 102 are sequentially passed to reach the target.

13 is a configuration diagram for remotely controlling the Faraday cup assembly of the particle measuring apparatus according to an embodiment of the present invention.

The particle measuring device may include a Faraday cup assembly 100, a programmable logic controller (PLC) control unit 510, and a PLC module unit 520.

Each device is connected with a conductor to send and receive signals. When the user inputs a command to the PLC control unit 510, the PCL control unit 510 receiving the command transmits a signal corresponding to the command to the PLC module unit 520. The PLC module unit 520 receiving the signal from the PLC control unit 510 drives the rotary drive unit 530 installed at one end of the rotary shaft 103 of the Faraday cup assembly 100 to change the position of the ring member 103. Here, the rotation driving unit 530 may be a stepping motor.

14 is a conceptual diagram illustrating a secondary electron suppression unit included in a particle measurement device according to an embodiment of the present invention.

When a charged particle beam, for example, a proton particle beam, is incident and collides with the surface of the first collector 102-A, secondary electrons are emitted, and a part of the emitted secondary electrons of the Faraday cup assembly 100 It is possible to escape to the outside of the Faraday cup assembly 100 through the entrance. In order to prevent the secondary electrons from escaping, the secondary electron suppressor 108 is installed and a voltage is applied.

When the output of the incident charged particle beam is high power, that is, the output of the charged particle beam is more than several hundred watts (W), the current measured from the charge caused by collision with the first collector 102-A may exceed several mA. have. In this case, it is difficult to accurately measure the incident amount of the charged particle beam incident only with the Faraday cup assembly 100 and the current waveform checking device 210. On the other hand, the first collector 102-A to which the charged particle beam of high current is incident generates heat due to the collision of the incident beam, and the amount of heat generated increases or decreases corresponding to the amount of the incident beam. That is, the size of the charged particle beam can be indirectly calculated by measuring the amount of heat generated at the incident site of the charged particle beam.

As described above, in order to measure the amount of charged particles incident per unit time even when the output of the incident charged particle beam is high power, the particle measuring apparatus according to an embodiment of the present invention is the first collection of charged particle beam incident The cooling unit 102-A may further include a third collection unit including a cooling system for measuring the amount of heat introduced and a heat amount measurement device.

15 is a detailed photo of the secondary electron suppression unit side of the particle measurement device manufactured according to an embodiment of the present invention.

16 illustrates an environment for measuring calories in a particle measuring device according to an embodiment of the present invention.

Referring to FIG. 16, the cooling passage 730 is generated in the first collecting part 102 -A provided in the ring member 102, and the inside of the rotating shaft 103 is configured to absorb heat transferred to the rotating shaft 103. The ring member 102 is formed to be in fluid communication with each other. The cooling passage 730 is an external cooling device (not shown) through a part of the ring member 102 from the inlet 103-A formed at one end of the rotating shaft 103 to the outlet 103-B formed at the other end. It is connected with. Inside the cooling passage, a fluid capable of absorbing heat generated by the ring member 102 and the rotating shaft 103 is filled.

In one embodiment, the sensor for measuring the amount of heat includes a first temperature sensor 710 and a second temperature sensor 720, and the temperature sensors are respectively installed at both ends of the cooling flow path to measure the temperature at both ends. When the charged particle beam collides with the first collecting section 102-A or the second collecting section 106, heat is generated, and a part of the generated heat is absorbed by the liquid passing through the cooling passage. The liquid that has entered the rotating shaft 103 from the injection hole 103-A absorbs heat while passing through the rotating shaft 103 and the ring member 102. Accordingly, the temperature of the liquid flowing out of the outlet 103-B is higher than when entering the inlet 103-A.

The first temperature sensor 710 is connected to the inlet 103-A to measure the temperature of the liquid injected into the inlet 103-A, and the second temperature sensor 720 is discharged from the outlet 103-B It is connected to the outlet (103-B) to measure the temperature of the liquid.

The second current value converting unit (not shown) receives the respective temperature values measured at both ends of the cooling flow path 730 from the first temperature sensor 710 and the second temperature sensor 720, and the temperature difference at both ends. Is converted to the amount of current. The converted current amount can be used to calculate the intensity of the charged particle beam or the number of particles incident per unit time.

The above description is merely illustrative of the technical spirit of one embodiment according to the present invention, and those of ordinary skill in the art to which one embodiment of the present invention pertains may vary in scope without departing from the essential characteristics of this embodiment Modifications and modifications will be possible. Therefore, the embodiments according to the present invention are not intended to limit the technical spirit of the present embodiment, but to explain, and the scope of the technical spirit of the present embodiment is not limited by these embodiments. The protection scope of one embodiment according to the present invention should be interpreted by the following claims, and all technical spirits within the equivalent range should be interpreted as being included in the scope of rights of one embodiment according to the present invention.

100: Faraday cup assembly 101: Flange
102: ring member 102-A: first collection portion
103: rotating shaft 103-A: inlet
103-B: outlet 104: insulator
105: O-ring 106: second collection unit
107: Suppression Magnet
108: Secondary Electron Suppression Unit
109: Housing 210: Current waveform checking device
220: data processing and storage device 510: PLC control unit
520: PLC module unit 530: rotary drive unit
710: first temperature sensor 720: second temperature sensor
730: cooling passage

Claims (5)

A vacuum box disposed on a transport path of a charged particle beam; And
Faraday Cup Assembly having a rotation axis perpendicular to the transport path in the vacuum box
Including,
The Faraday cup assembly,
A ring member disposed around an intersection of the transport path and the rotation axis;
A first collection part disposed on a bonding surface that is a plane formed on one side of the circumferential surface of the ring member, the plane being parallel to a plane including the central axis and the rotation axis of the ring member;
A second collection part disposed between the inlet of the vacuum box to which the charged particle beam is incident and the ring member, and in the form of a cylinder surrounding the transport path; And
A third collection unit including a cooling flow path formed inside the rotating shaft and the ring member and a heat sensor for measuring the amount of heat flowing into the cooling flow path by a charged particle beam incident on the first collection portion.
Including,
When the ring member is rotated to a first position where the central axis of the ring member is parallel to the transport path, the charged particle beam passes through the ring member,
When the ring member is rotated to a second position where the charged particle beam is vertically incident on the first collecting portion, the incident amount of the charged particle beam is measured by the first collecting portion and the second collecting portion,
The first collection portion is made of graphite, and the first collection portion is bonded to the bonding surface by brazing to ensure high vacuum and ease of assembly of the transport system, 1 The bonding layer between the collecting part and the bonding surface includes a silver paste so as to favor heat transfer.
Charged particle beam current measurement device. delete delete According to claim 1,
The bonding surface,
The bottom surface of the pocket portion is formed so that the inner wall and at least a portion of the side surface of the first collection portion
Charged particle beam current measurement device. According to claim 1,
The thickness of the first collection portion,
The charged particle beam is formed to be greater than or equal to the penetration depth of the charged particle beam according to the energy size and the material characteristics of the first collector.
Charged particle beam current measurement device.

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