JP3343028B2 - Beam emission device of charged particle accelerator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a beam emitting device for a circular charged particle accelerator.

[0002]

2. Description of the Related Art FIG.
instruments and Methods in
Physics Research A326 ”39
Page 9 "Slow Beam Extraction"
FIG. 2 is a layout view of a conventional charged particle accelerator shown in “TARN II”. In FIG. 2, reference numeral 1 denotes a bending electromagnet, 2 denotes a quadrupole electromagnet, 3 denotes a high-frequency cavity, and 4 denotes a hexapole electromagnet used for beam extraction. Reference numeral 5 denotes a knockout electrode for increasing the amplitude of particles, 6a denotes an output electrostatic septum for cutting out a circulating beam, and 6b denotes a septum electromagnet for guiding the output beam to a beam transport system.

Next, the operation of this conventional example will be described. In the circular accelerator, charged particles are caused to circulate by the bending electromagnet 1 while repeating convergence and anti-convergence by the quadrupole electromagnet 2. Motion due to repeated convergence and anti-convergence of charged particles is called betatron oscillation. When the betatron frequency ν satisfies the following equation, the resonance condition is established due to a small error magnetic field in the circular accelerator, and the charged particles rapidly move away from the center orbit of the beam. Integer = n × ν (n: an arbitrary integer) The magnetic field formed by the hexapole electromagnet 4 has a converging force or an anti-converging force that increases as the amplitude of the charged particles increases. This means that the betatron frequency changes depending on the amplitude. Here, when the circular accelerator is operated at a betatron frequency close to the resonance condition and the hexapole electromagnet 4 is excited, a stable region and an unstable region depending on the amplitude are formed. FIG.
As shown in the figure, in the initial state, all particles are present in the stable region. However, when an AC electromagnetic field having the following frequency is applied to the knockout electrode 5, the amplitude of the particle vibration increases and the particles exist in the unstable region. I will be. f = fraction of the betatron frequency (Δν) × circulation frequency (frev) × integer Particles in the unstable region are cut out by the emission electrostatic septum 6a and taken out of the accelerator by the septum electromagnet 6b.

[0004]

Since the conventional beam emitting device of the circular charged particle accelerator is configured as described above, it excites the betatron oscillation at one frequency,
In order to obtain an amplitude at which the beam can be extracted, the knockout electrode 5 and the input AC power that are large enough to increase the amplitude even when the input frequency deviates from the betatron frequency are required. Also, because the width of the integer order resonance of the betatron oscillation changes with time due to the ripple of the power supply of the quadrupole electromagnet 2, and because the density distribution of the charged particles in the beam cross section is not uniform, the current of the output beam is temporally reduced. There were problems such as changes.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. By inputting AC power of a finite plurality of frequencies, even if the betatron frequency fluctuates, the beta is always obtained. An object of the present invention is to obtain an inexpensive and compact beam emitting device for a charged particle accelerator, which can excite vibration at a frequency close to an integral multiple of the frequency corresponding to the thoron frequency, thereby reducing input power. I do.

Another object of the present invention is to distribute a larger amount of input AC power frequency in a frequency band in which the amount of change in the frequency of the betatron is larger than the amount of change in the amplitude, so that the AC power necessary for each frequency is distributed. An object of the present invention is to provide a beam emitting device for a charged particle accelerator which is inexpensive and easy to control and has uniform power.

It is still another object of the present invention to provide a highly reliable beam emitting device for a charged particle accelerator which has a simple structure and can be manufactured at low cost.

It is still another object of the present invention to separately set the respective amounts of input AC power of each frequency to an optimum value in advance, thereby making it possible to excite betatron oscillation with less input AC power. It is an object of the present invention to provide a beam accelerator for a particle accelerator.

Still another object of the present invention is to feed back the output beam current value to an AC power generation device,
An object of the present invention is to provide a beam emission device of a charged particle accelerator capable of removing a time change of an emission beam current value.

Still another object of the present invention is to provide a beam emitting device of a charged particle accelerator which is inexpensive and compact and can remove a change in the emitted beam current value with time.

Still another object of the present invention is to provide a beam emitting device of a charged particle accelerator capable of performing finer feedback control and having a smaller time variation of an emitted beam current value.

Still another object of the present invention is to make it possible to easily adjust the extraction time and the output beam current value to the user's desire of the output beam by using a computer for calculating the feedback control function. An object of the present invention is to provide a beam emission device for a charged particle accelerator.

Still another object of the present invention is to provide a beam emission device for a charged particle accelerator capable of removing a fast time change of a beam current value which cannot be followed by a computer by adding a feedback loop by an analog arithmetic circuit. To get.

Still another object of the present invention is to read a stored beam current value as one of the input parameters of the feedback control function into a computer, calculate the output beam current value with respect to the extraction time from the stored beam current value, and output the output beam current value. It is an object of the present invention to obtain a beam extraction device of a charged particle accelerator which calculates a value extraction time and can meet a user's desire for a more complicated emission beam.

[0015]

The invention according to claim 1 is
In a charged particle accelerator that accelerates charged particles while accumulating energy while circulating, and extracts the beam using the resonance phenomenon of the charged particle beam, inputs AC power of finite multiple frequencies and generates it a beam emission device Ru vibrate the beam by an electric field that is, narrow beam
Knockout electrode with two electrodes and the basic
Synthesizer that generates frequency and synthesizer
Between the frequency that excites the betatron oscillation
Multiple frequency fixed oscillators that generate
The amount of power is set to an optimal value and
Amplify fixed wave number oscillator output with different gains
The first AC power amplifier to
Combiner and the output signal from the synthesizer
And a multiplier for multiplying the set frequency.
The signal is input to the knockout electrode.

[0016]

According to a second aspect of the present invention, an output signal of the multiplier is provided.
Knocks after being amplified by the second AC power amplifier.
Input to the out electrode.

In the invention according to claim 3, the plurality of frequencies are:
Betatron frequency fine relative to betatron oscillation amplitude
It is distributed in proportion to the absolute value of the minute value.

According to a fourth aspect of the present invention, there is provided an output beam current value.
Further comprising an output beam current monitor for measuring
Second AC power amplification so as to keep the beam current value constant
Feedback to the vessel.

According to a fifth aspect of the present invention, there is provided an output beam current value.
Further comprising an output beam current monitor for measuring
A plurality of first AC power sources are used to maintain the beam current value at a constant value.
Select and feedback part or all of the power amplifier
I do.

According to a sixth aspect of the present invention, there is provided an output beam current
Analog / digital conversion of monitor output to analog / digital
Digital converter and analog / digital converter output
Input and increase the amplification factor when the output beam current value is small.
Feedback control function to reduce the amplification factor
A computer that calculates the amplification factor for each frequency by using
To the first AC power by converting the output of
Digital / input to the amplifier or the second AC power amplifier
And an analog converter.

According to a seventh aspect of the present invention, there is provided an output beam current.
Input monitor output and feedback with analog element
Further comprising an analog arithmetic unit for calculating the clock control function,
Feedback of the current change of the output beam at a speed higher than a predetermined speed
The calculation of the control function is calculated by the
Feedback control of current change at a speed less than predetermined
Calculate the function with a calculator.

The invention according to claim 8 is characterized in that the accumulated beam current value
Beam current monitor for measuring the
Analog that converts the output of the current monitor to analog / digital
Analog / digital converter, further comprising:
The output of the converter is input to the computer and the accumulated beam current
While controlling the output beam current value.

According to a ninth aspect of the present invention, the charged particles are circulated.
Accelerating while accumulating energy, the charged particle beam
Particle acceleration to extract a beam using the resonance phenomenon
Input a limited number of frequencies of AC power
Vibrating the beam by the electric field generated by
Beam extraction device, which is arranged to sandwich the beam.
Betatron oscillation amplitude of the beam with two electrodes
Is proportional to the absolute value of the derivative of the betatron frequency with respect to
Are input to the electrodes, and
Knocks to oscillate the beam by the generated electric field
It has an out electrode.

[0025]

[0026]

[0027]

[0028]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

Embodiment 1 First, in a charged particle accelerator that accelerates while rotating charged particles and accumulates energy, and extracts a beam using the resonance phenomenon of the charged particle beam, input AC power of a finite number of frequencies,
A first embodiment of the present invention in which a beam is oscillated by an electric field generated thereby and extracted is described. FIG. 1 is a diagram showing the relationship between the betatron oscillation amplitude and the betatron frequency (Δν) × circulation frequency (frev) according to the first embodiment of the present invention, which will be described below with reference to FIG. In FIG. 1, the horizontal axis is the betatron oscillation amplitude, and the vertical axis is the betatron frequency (Δν) × circulation frequency (frev).
× Integer (n) Optimal frequency fi to excite betatron oscillation
deal is represented by the following equation. fieldal = Δν × frev × n Since the betatron frequency depends on its amplitude, the optimal frequency field also changes.

Next, the operation of the first embodiment will be described. A horizontal or vertical electric field is created with a certain finite number of AC powers, between a frequency at the center of the beam orbit and a field at the amplitude required for beam emission. For example, when a finite plurality of AC powers f1 to fn are equally spaced (for example, if f1 is a
1), the charged particles near the center of the beam orbit are kicked by the AC power f1 with good timing, and the amplitude of the betatron oscillation gradually increases. When the amplitude increases, the betatron frequency changes, and then the AC power f2
Will be kicked with good timing. In this way, finally, the charged particles near the center of the beam orbit are kicked at a good timing by the AC power fn, and have the amplitude required at the time of beam emission, and are circularly formed by devices such as the electrostatic septum 6a for extraction and the septum electromagnet 6b. It is taken out of the accelerator.
Therefore, when a beam is kicked at one frequency, the input power for kicking to a predetermined amplitude is smaller than that of the above-described conventional example, and the beam can be manufactured at low cost.

Embodiment 2 Next, a description will be given of a second embodiment in which the frequency of the AC power to be input is distributed in proportion to the absolute value of the derivative of the betatron frequency with respect to the betatron oscillation amplitude in the first embodiment. . FIG. 4 is a diagram showing the relationship between betatron oscillation amplitude and betatron frequency (Δν) × circulation frequency (frev) according to Embodiment 2 of the present invention.
It will be described based on. FIG. 4 shows the distribution condition of the frequency of the AC power for exciting the betatron oscillation on the curve showing the betatron oscillation amplitude dependence of the betatron frequency of FIG. 1 showing the first embodiment of the present invention. .

Next, the operation of the second embodiment will be described. In order to obtain a constant change amount of the betatron oscillation amplitude, it is necessary to input AC power proportional to the differential value dfideal / dx of the betatron frequency with respect to the betatron oscillation amplitude at the amplitude xi. In the second embodiment, the frequency of the AC power is distributed in proportion to the differential value dfideal / dx, that is, | (fi-1-fi) | × dfideal / dx ≒ |
The frequencies are distributed so that (fi-1-fi) 2 / (xi-xi-1) | = constant, and the power amount of each frequency is made equal to excite the betatron oscillation. Therefore,
Since the amount of power at each frequency is the same, the number of control points of the beam emitting device can be reduced, and controllability can be improved at low cost.

Embodiment 3 FIG. 5 shows a beam emitting device according to Embodiment 3 of the present invention. In FIG. 5, reference numerals 5a, 5b, and 5c denote knockout electrodes having two electrodes with the beam interposed therebetween, and reference numerals 7a, 7b, and 7c.
Is a synthesizer for generating AC signals of different frequencies f1, f2, f3 for the respective knockout electrodes 5a, 5b, 5c, and 8 is a synthesizer 7a, 7
b, 7c to amplify the AC signal and knock out electrode 5a,
This is an AC power amplifier that supplies AC power to 5b and 5c.

Next, the operation of the third embodiment will be described. F1, f2,... In the order in which the frequency of the AC signal is closest to the betatron frequency of the charged particle near the center of the beam orbit.
Assuming that the frequency is f3, the AC signal of the frequency f1 generated by the synthesizer 7a is power-amplified by the AC power amplifier 8 and input to the knockout electrode 5a to kick charged particles near the center of the beam orbit with good timing. Excites vibration. If the betatron oscillation amplitude increases, it becomes impossible to kick efficiently at the timing of f1. Next, the charged particles are kicked with good timing via the knockout electrode 5b by the AC signal of the frequency f2 generated by the synthesizer 7b,
Further, the amplitude of the betatron oscillation increases. f2
When it becomes impossible to kick efficiently at the timing, the charged particle is kicked through the knockout electrode 5c with good timing by the AC signal of the frequency f3 generated by the synthesizer 7c. The condition of the resonance of the order of the vibration is satisfied, and the charged particles are emitted. In this way, the same function as in the first embodiment can be achieved. In the third embodiment, three sets of synthesizers, AC power amplifiers, and knockout electrodes are used. However, if two or more sets are used, similar effects can be obtained. Since a knockout electrode, a synthesizer, and an AC power amplifier are used for each frequency, functions similar to those of the second embodiment can be easily achieved.

Embodiment 4 FIG. FIG. 6 shows a beam emitting device according to Embodiment 4 of the present invention. In FIG. 6, reference numeral 5 denotes a knockout electrode having two electrodes with the beam interposed therebetween, and reference numerals 7a, 7b, 7c, 7d denote different frequencies f1, f2, f3,.
A synthesizer for generating an AC signal of fn; an AC power amplifier 8 for amplifying the AC signals of the synthesizers 7a, 7b, 7c and 7d; and a superimposing AC power of each frequency 9 to one knockout electrode Output coupler.

The operation of the fourth embodiment is the same as that of the third embodiment. However, since the AC power is superposed by the coupler 9 and the charged particles are kicked by one knockout electrode, the operation is more inexpensive. Can be manufactured.

Embodiment 5 FIG. 7 is a schematic diagram showing Embodiment 5 of the present invention. In FIG. 7, reference numeral 5 denotes a knockout electrode having two electrodes with the beam interposed therebetween.
Reference numerals 7a, 7b, 7c, and 7d denote synthesizers for generating AC signals having different frequencies f1, f2, f3,... Fn to the knockout electrode 5, and 9 denotes one output obtained by superposing the AC power of each frequency. And 8 is an AC power amplifier for amplifying the output of the combiner 9.

The operation of the fifth embodiment is the same as that of the fourth embodiment, except that a plurality of frequencies are superimposed by the coupler 9 and then amplified by one AC power amplifier 8, so that the configuration of the equipment is The number of points is reduced, and it can be manufactured at low cost.

Embodiment 6 FIG. FIG. 8 is a schematic diagram showing Embodiment 6 of the present invention. In FIG. 8, reference numeral 5 denotes a knockout electrode having two electrodes with the beam interposed therebetween.
7 is a synthesizer for generating a basic frequency,
Reference numerals 10a, 10b, and 10c denote frequency fixed oscillators that generate differences Δf1, Δf2, and Δfn between frequencies generated by the synthesizer 7 and frequencies input to excite betatron oscillation. A combiner 11 includes an output signal from the synthesizer 7 having the frequency f0 and the frequencies Δf1, Δf2, and Δf.
n is a mixer for multiplying the superimposed signal, and the output signal of the mixer 11 is input to the knockout electrode 5 after being amplified by the AC power amplifier 8.

Next, the operation of the sixth embodiment will be described. The AC power output from the mixer 11 is f0 ± Δf
1, f0 ± Δf2,... F0 ± Δfn are signals that are superimposed and input to the knockout electrode 5. F0- [Delta] fn, f0- [Delta] fn-1 in order of closest to the betatron frequency of the charged particle near the beam orbit center.
... Assuming that f0 + Δfn, the frequency f
When the AC power of 0-Δfn is inputted to the knockout electrode 5, the AC power of 0-Δfn kicks charged particles near the center of the beam orbit with good timing and excites betatron oscillation. When the betatron oscillation amplitude increases, it cannot be efficiently kicked at the timing of f0−Δfn. Next, the charged particles are kicked through the knockout electrode 5 with good timing by the AC power of the frequency f0−Δfn−1. In this manner, the amplitude of the betatron oscillation finally increases, and the charged particles are kicked with good timing through the knockout electrode 5 by the AC power having the frequency f0 + Δfn. Charged particles are emitted under the conditions. Since the synthesizer 7 is a circuit that can set the frequency arbitrarily, it is more expensive than a fixed frequency oscillator, and can be made inexpensive because the number of synthesizers 7 can be configured by one.

Embodiment 7 FIG. FIG. 9 shows a seventh embodiment of the present invention. In FIG. 9, reference numeral 5 denotes a knockout electrode having two electrodes sandwiching a beam, 7 denotes a synthesizer that generates a fundamental frequency, and 10 denotes a knockout electrode.
Reference numerals a, 10b, and 10c denote frequency fixed oscillators that generate differences Δf1, Δf2, and Δfn between the frequency generated by the synthesizer 7 and the frequency input to excite the betatron oscillation.
a, 10b, and 10c are AC power amplifiers that amplify the outputs with different gains, respectively.
A coupler 12 superimposes f2 and Δfn. Reference numeral 12 denotes an output signal from the synthesizer 7 having a frequency f0 and a frequency Δf.
1, .DELTA.f2, .DELTA.fn are analog multipliers for multiplying the superimposed signals, and 13 is an analog multiplier 12
Is a low-pass filter that discriminates the frequency of the signal output from the low-pass filter 13. The output signal of the low-pass filter 13 is input to the knockout electrode 5 after being amplified by the AC power amplifier 8.

Next, the operation will be described. The AC power output from the analog multiplier 13 is f0 ± Δf1, f0 ± Δ
.., f0 ± Δfn are superimposed, and the frequencies are discriminated by passing through the low-pass filter 13, and the outputs are f0, f0 + Δf1, f0 + Δ.
.., f0 + Δfn are superimposed signals. Here, AC power amplifiers 8a, 8b, 8c
Are G1, G2, and Gn, the outputs f0, f0 + Δf1, f0 + Δf2,.
... The ratio of the amplitudes of f0 + Δfn is G1: G2:.
Gn is input to the knockout electrode 5 after being amplified by the AC power amplifier 8. F0, f0 + in order of closest to the betatron frequency of the charged particle near the center of the beam orbit
Assuming that Δf1, f0 + Δf2... F0 + Δfn, the AC power having the frequency f0, when input to the knockout electrode 5, kicks charged particles near the center of the beam orbit with good timing to excite betatron oscillation. .
If the betatron oscillation amplitude increases, it becomes impossible to kick efficiently at the timing of f0. next,
With the AC power of the frequency f0 + Δf1, the charged particles are kicked through the knockout electrode 5 with good timing. In this manner, the amplitude of the betatron oscillation finally increases, and the charged particles are kicked with good timing through the knockout electrode 5 by the AC power having the frequency f0 + Δfn. Under the condition, charged particles are emitted. Here, the fixed frequency oscillators 10a, 10b, and 10c often use crystal oscillators, and commercially available products having an optimum frequency may not be obtained. In this case, by adjusting the values of G1 to Gn, the AC power to the knockout electrode can be set to an optimal value. Therefore, according to this embodiment, the cost can be reduced as compared with the sixth embodiment. In this way, the input power of the AC power can be minimized using an inexpensive crystal oscillator. Although the seventh embodiment has been described using a crystal oscillator, another oscillator such as a SAW device may be used, and the same effect can be obtained.

Embodiment 8 FIG. FIG. 10 is a schematic diagram showing an eighth embodiment of the present invention. In FIG. 10, reference numeral 5 denotes a knockout electrode having two electrodes sandwiching the beam, 7 denotes a synthesizer for generating a frequency for exciting betatron oscillation, and 14 denotes an output beam for measuring an output beam current. A current monitor 15 for calculating a function using the output of the output beam current monitor 14 as an input parameter; and 16 amplifying the output of the synthesizer 7 by changing the amplification factor according to the output of the arithmetic device 15. This is a variable gain amplifier that outputs AC power to the knockout electrode 5.

Next, the operation of the eighth embodiment will be described. Betatron oscillation is excited by an AC electric field of a frequency generated by the synthesizer 7, and the condition of integer order resonance of the betatron oscillation is satisfied, and charged particles are emitted to the outside. Emitted charged particles per unit time (current)
Varies over time due to ripples of a quadrupole electromagnet or the like that cause resonance conditions and the non-uniformity of the spatial distribution of charged particles in the cross section of the accumulated beam. The output beam current monitor 14 outputs a voltage proportional to the output beam current. The arithmetic unit 15 sets a gain of the variable gain amplifier 16 by calculating a function of increasing the amplification factor when the emission beam current is small and decreasing the amplification factor when the emission beam current is large from the output value of the emission beam current monitor 14. I do. With such a feedback loop, the output beam current can be maintained at a constant value.

Embodiment 9 FIG. FIG. 11 is a schematic diagram showing Embodiment 9 of the present invention. In FIG. 11, reference numeral 5 denotes a knockout electrode having two electrodes with the beam interposed therebetween. Reference numerals 7a, 7b, and 7c generate AC signals having different frequencies f1, f2,. 8 is a synthesizer, and 8 is a synthesizer 7a, 7
b, an AC power amplifier for amplifying the AC signal of 7c,
Reference numeral 9 denotes a coupler that superimposes and outputs the AC power of each frequency, 14 denotes an output beam current monitor that measures the output beam current, and 15 denotes an output beam current monitor 14.
And 16 is a variable gain amplifier that changes the amplification factor according to the output of the arithmetic unit 15 to amplify the output of the synthesizer 7 and outputs AC power to the knockout electrode. .

Next, the operation of the ninth embodiment will be described. The AC signals having different frequencies f1, f2,... Fn are superposed by the coupler 9, amplified by the variable gain amplifier 16 set to the initial amplification rate, and input to the knockout electrode 5. . Charged particles in the vicinity of the beam center orbit are firstly kicked by AC power having the frequency of f1, then f2, and finally fn, and are emitted to the outside under conditions of integer order resonance. The outgoing beam current is measured by the outgoing beam current monitor 14, calculated by the arithmetic unit 15 as in the eighth embodiment, and the result is set in the variable gain amplifier 16. Since charged particles can be kicked at a finite number of frequencies, the functions of the first to seventh embodiments can be provided in addition to the eighth embodiment. Can also be inexpensive.

Embodiment 10 FIG. FIG. 12 is a schematic diagram showing a tenth embodiment of the present invention. In FIG. 12, reference numeral 14 denotes an output beam current monitor for measuring an output beam current, and reference numeral 15 denotes an arithmetic unit that performs a function operation using the output of the output beam current monitor 14 as an input parameter.
8 is a switch for changing the output destination of the result of the arithmetic unit,
Numeral 5 denotes a knockout electrode having two electrodes with the beam interposed therebetween. Numerals 7a, 7b and 7c denote synthesizers for generating AC signals having different frequencies f1, f2,... Fn to the knockout electrode 5, respectively. , 16b, 16c
Is a variable gain amplifier that amplifies each of the AC signals of the synthesizers 7a, 7b, 7c by changing the amplification factor in accordance with the output result of the arithmetic unit 15, and 9 outputs the AC power of each frequency to the knockout electrode 5 by superimposing them. It is a combiner.

The operation of the tenth embodiment is the same as that of the ninth embodiment except that the gain variable amplifiers 16a, 16b, 16c are provided for each frequency of f1, f2,.
Is provided, and it is possible to select the amplification factor of which frequency the feedback control is performed by the switch 18. Therefore, more precise feedback control can be performed than in the inventions of the above-described ninth and tenth embodiments, and the beam with less time variation Emission can be performed.

Embodiment 11 FIG. FIG. 13 is a schematic diagram showing Embodiment 11 of the present invention. In FIG. 13, reference numeral 5 denotes a knockout electrode having two electrodes sandwiching the beam, 7 denotes a synthesizer that generates a frequency for exciting betatron oscillation, and 14 denotes an output beam for measuring an output beam current. Is an A / D converter for converting the output of the output beam current monitor 14 from analog to digital, and 20 is a digital data output from the A / D converter 19 to calculate an amplification factor to be changed. A computer 21 outputs data. Reference numeral 21 denotes a D which converts digital amplification factor data output from the computer 20 into analog data.
Reference numeral 16 denotes an A converter, and a variable gain amplifier 16 changes the amplification factor in accordance with the output of the DA converter 21 to amplify the output of the synthesizer 7 and outputs AC power to the knockout electrode.

Next, the operation of the eleventh embodiment will be described. The computing device according to the eighth embodiment has a computer 2
0, the combination of the AD converter 19 and the DA converter 21 is used, and the operation of the feedback control is the same as that of the eighth embodiment. However, since the calculation of the feedback control function is performed by the computer 20, As input parameters of the feedback control function, required values (emission beam pulse width, emission beam intensity, emission beam intensity pattern) from the user of the emission beam can be input in advance. Therefore, the usability for the user of the output beam is improved. If a digital signal processor is used as the computer 20, high-speed arithmetic processing can be performed, and control accuracy can be further improved.

Embodiment 12 FIG. FIG. 14 is a schematic diagram showing a twelfth embodiment of the present invention. In FIG. 14, reference numeral 5 denotes a knockout electrode having two electrodes sandwiching the beam, 7 denotes a synthesizer for generating a frequency for exciting betatron oscillation, and 14 denotes an output beam for measuring an output beam current. Is an A / D converter for converting the output of the output beam current monitor 14 from analog to digital, and 20 is a digital data output from the A / D converter 19 to calculate the amplification factor data to be changed. Reference numeral 21 denotes a computer which outputs digital data. Reference numeral 21 denotes a DA converter which converts digital amplification factor data output from the computer into analog data. Reference numeral 15a denotes a feedback function which is calculated by an analog element using an output voltage of the output beam current monitor 14 as an input. 22 is an analog arithmetic unit, and 22 is a DA converter 2
1 is an adder for adding the output voltage of the analog operation device 15a to the output voltage of the analog operation device 15a. The adder 16 changes the amplification factor in accordance with the output of the adder 22, amplifies the output of the synthesizer 7, and outputs AC power to the knockout electrode. Variable gain amplifier.

Next, the operation of the twelfth embodiment will be described. Due to the ripple of the power supply such as a bending electromagnet, a quadrupole electromagnet, or a hexapole electromagnet installed in the circular charged particle accelerator, a change in the output beam current due to the ripple of the power appears in the output beam current. This time change is caused by the commercial AC power supply frequency (50
変 化 60 Hz) to about 1 MHz, and in the feedback control by the computer 20 of the eleventh embodiment, the control speed may not catch up. Therefore, the computer 20 performs a feedback control function operation on a relatively slow change in the output beam current, and the analog operation device 15a performs a feedback control function operation on a fast change in the output beam current. Since the required values (the output beam pulse width, the output beam intensity, and the output beam intensity pattern) of the output beam user can be set by slow control, the ease of use for the output beam user is the invention of the eleventh embodiment. And the rapid change of the output beam current with time can be eliminated.

Embodiment 13 FIG. FIG. 15 is a schematic diagram showing Embodiment 13 of the present invention. In FIG. 15, reference numeral 5 denotes a knockout electrode having two electrodes sandwiching the beam, 7 denotes a synthesizer for generating a frequency for exciting betatron oscillation, and 14 denotes an output beam for measuring an output beam current. 23 is a storage beam current monitor for measuring the storage beam current,
Reference numeral 19 denotes an AD converter for converting the output of the output beam current monitor 14 or the output of the accumulated beam current monitor 23 from analog to digital.
Is a computer that calculates the digital data output from the computer and outputs the amplification factor data to be changed. Reference numeral 21 denotes a D that converts the digital amplification factor data output from the computer 20 to analog.
Reference numeral 16 denotes an A converter, and a variable gain amplifier 16 changes the amplification factor in accordance with the output of the DA converter 21 to amplify the output of the synthesizer 7 and outputs AC power to the knockout electrode 5.

Next, the operation of the thirteenth embodiment will be described. The configuration according to the eleventh embodiment is different from the configuration according to the eleventh embodiment in that a configuration in which the accumulated beam current value is converted into digital data and input to the computer 20 is added, and the output beam current is controlled while constantly monitoring the accumulated beam. can do. The computer 20 accumulates the accumulated beam current from the initial accumulated beam current in response to the special requirement of the user of the emitted beam, for example, “extract as much beam current as possible within the designated emission pulse time without changing the time”. It calculates the total charge amount of the charged particles, and calculates and outputs the gain setting value of the gain variable amplifier 16 so as to obtain an output beam current obtained by dividing the value by a specified output pulse time. In this way, it is possible to respond to the special requirements of the user of the outgoing beam as compared with the invention of the eleventh embodiment, and the usability is improved.

[0055]

As described above, the present invention has the following excellent effects. According to the first aspect of the present invention, the charged particles are accelerated while circling to store energy.
The beam using the resonance phenomenon of the charged particle beam.
In the extracted charged particle accelerator, a finite number of frequencies
Input the AC power of the
A beam emitting device for oscillating a beam, comprising:
Knockout electrode with two electrodes sandwiching
Synthesizers that generate different frequencies
Between the generated frequency and the frequency that excites the betatron oscillation.
A plurality of fixed frequency oscillators that generate differences
AC power is set to the optimal value and multiple
Output of fixed frequency oscillators with different gains
A first AC power amplifier to be amplified is superimposed on a plurality of frequencies.
Combiner and the output signal from the synthesizer
And a multiplier for multiplying the combined frequency.
The output signal is input to the knockout electrode. for that reason,
The amplification factor of each AC power of each frequency
It can be set to an appropriate value, and the amount of power for each frequency is
Can be optimized separately, so that overall
Exciting betatron oscillation with low input AC power
Can be. Also, use one expensive synthesizer
And a plurality of fixed frequency oscillators, for example, crystal
Inexpensive devices such as oscillators can be used.
It can be a beam emitting device.

[0056]

According to the second aspect of the present invention, the output signal of the multiplier is
Is knocked after being amplified by the second AC power amplifier.
Input to the out electrode. Therefore, it is possible to manufacture a highly reliable beam emitting device for a charged particle accelerator with a simple configuration and at low cost.

According to the third aspect of the present invention, a plurality of frequencies
Is the betatron frequency relative to the betatron oscillation amplitude
Are distributed in proportion to the absolute value of the differential value of. for that reason,
Betatron frequency change is larger than amplitude change
More AC power frequencies in the
The AC power required for each frequency
Charged particles that are inexpensive and easy to control
It can be a beam emitting device of an accelerator.

According to the fourth aspect of the present invention, the output beam current
An output beam current monitor for measuring the
The second AC power is increased to keep the beam current value constant.
Feedback to breadth. Therefore, the output beam current
Value to the second AC power amplifier.
As a result, it is possible to eliminate the time change of the output beam current value.
Wear.

According to the fifth aspect of the present invention, the output beam current
An output beam current monitor for measuring the
A plurality of first alternating currents so as to keep the beam current value constant.
Select some or all of the power amplifier to provide feedback
Click. Therefore, a more detailed feedback system
Control and the time change of the output beam current value is smaller.
Can be done.

According to the invention of claim 6, the output beam power is
Analog that converts the output of the current monitor to analog / digital
/ Digital converter and output of analog / digital converter
And when the output beam current value is small,
Feedback control
A calculator that calculates the amplification factor for each frequency by the number,
Digital-to-analog conversion of the machine output and the first AC power
Digital input to amplifier or second AC power amplifier
/ Analog converter. Therefore,
To use a computer to calculate feedback control functions
Therefore, the extraction time and the output beam current value can be easily adjusted.
It can be adjusted to the desire of the user of the output beam.

According to the seventh aspect of the present invention, the output beam
Input of the current monitor and feedback with analog element
Analog operation device for calculating the
In addition, the feed of the current change of the output beam more than a predetermined speed
The operation of the back control function is calculated by the analog
Feedback of current changes at less than a predetermined rate of the radiation beam
The calculation of the control function is performed by a computer. Therefore, Ana
Add feedback loop by log operation circuit
With this, the beam current value that cannot be tracked by the computer is fast
It is possible to remove the time change.

According to the eighth aspect of the present invention, the accumulated beam current
Current monitor for stored beam to measure the value and for stored beam
Analog that converts the current monitor output from analog to digital
And an analog / digital converter.
The output of the Tal transducer is input to a computer and the accumulated beam current
The output beam current value is controlled while monitoring the value. That
From the accumulated beam current value,
Calculation of beam current value, extraction time of output beam current value
To calculate the more complex output beam.
Can be adjusted to the user's wishes.

According to the ninth aspect of the present invention, the charged particles circulate around
While accelerating while accumulating energy,
Charged particle extraction to extract the beam using the
Input a limited number of frequencies of AC power
Vibrating the beam by the electric field generated by
Beam extraction device, which is arranged to sandwich the beam.
Betatron oscillation amplitude of the beam with two electrodes
Is proportional to the absolute value of the derivative of the betatron frequency with respect to
Are input to the electrodes, and
Knocks to oscillate the beam by the generated electric field
It has an out electrode.

[0065]

[0066]

[0067]

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between betatron oscillation amplitude and betatron frequency according to Embodiment 1 of the present invention.

FIG. 2 is a configuration diagram of a circular charged particle accelerator including a conventional beam emitting device.

FIG. 3 is a graph showing the relationship between the betatron oscillation amplitude and the fraction of the betatron frequency of the conventional circular charged particle accelerator.

FIG. 4 is a graph showing the relationship between betatron oscillation amplitude and betatron frequency according to Embodiment 2 of the present invention.

FIG. 5 is a device configuration diagram showing a third embodiment of the present invention.

FIG. 6 is a device configuration diagram showing a fourth embodiment of the present invention.

FIG. 7 is a device configuration diagram showing a fifth embodiment of the present invention.

FIG. 8 is a device configuration diagram showing a sixth embodiment of the present invention.

FIG. 9 is a device configuration diagram showing a seventh embodiment of the present invention.

FIG. 10 is a device configuration diagram showing Embodiment 8 of the present invention.

FIG. 11 is a device configuration diagram showing a ninth embodiment of the present invention.

FIG. 12 is a device configuration diagram showing a tenth embodiment of the present invention.

FIG. 13 is a device configuration diagram showing Embodiment 11 of the present invention.

FIG. 14 is a device configuration diagram showing a twelfth embodiment of the present invention.

FIG. 15 is a device configuration diagram showing a thirteenth embodiment of the present invention.

[Explanation of symbols]

1 bending magnet, 2 quadrupole magnet, 3 high frequency cavity, 4
Hexapole electromagnet, 5, 5a, 5b, 5c Knockout electrode, 6a Electrostatic septum for emission, 6b Septum electromagnet, 7, 7a, 7b, 7c Synthesizer, 8 AC power amplifier, 9 coupler, 10a, 10b, 10c Fixed frequency Oscillator, 11 mixer, 12 analog multiplier, 13 low-pass filter, 14 current monitor for outgoing beam, 15, 15a arithmetic unit, 16, 16a, 16
b, 16c Variable gain amplifier, 18 switch, 19 A
D converter, 20 computer, 21 DA converter, 22 adder, 23 Current monitor for accumulated beam.

Continuation of the front page (56) References JP-A-5-258900 (JP, A) JP-A-5-198397 (JP, A) JP-A-9-115700 (JP, A) JP-A-9-45499 (JP, A) JP-A-9-35899 (JP, A) JP-A-8-64400 (JP, A) JP-A-8-203700 (JP, A) JP-A-4-196099 (JP, A) 5-62799 (JP, A) JP-A-6-61000 (JP, A) JP-A-7-249499 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H05H 13/04

Claims (9)

(57) [Claims] 1. A method for accelerating energy while rotating charged particles.
Accumulate energy and use the resonance phenomenon of the charged particle beam
In a charged particle accelerator that extracts a beam by
Input AC power at a number of frequencies, thereby producing
Vibrating the beam with the electric fieldBeam emitting device
hand, Knockout electrode having two electrodes sandwiching the beam
When, A synthesizer that generates the basic frequency Frequency generated by the synthesizer and betatron oscillation
Fixed multiple frequencies that generate a difference from the frequency that excites
An oscillator, Set the amount of AC power of each frequency to the optimal value.
Output of the plurality of fixed frequency oscillators.
A first AC power amplifier that amplifies with the gain, A combiner for superimposing the plurality of frequencies, The output signal from the synthesizer is superimposed on the output signal.
A multiplier for multiplying the frequency, The output signal of the multiplier is input to the knockout electrode.
Be A beam extraction device characterized by the above-mentioned. 2. An output signal of the multiplier is a second AC power supply.
Input to the knockout electrode after being amplified by the power amplifier.
Beam emission of claim 1, characterized in that the force
apparatus. 3. The betatron according to claim 2, wherein the plurality of frequencies are
Absolute value of derivative of betatron frequency with respect to vibration amplitude
Claim 1 or Claim 2 characterized by being distributed in proportion to
3. The beam output device according to 2. (4)Outgoing beam for measuring outgoing beam current value
Further equipped with a current monitor for In order to keep the output beam current value constant, the second
Feedback to AC power amplifier Characterized by
The beam emitting device according to claim 2. (5)Outgoing beam for measuring outgoing beam current value
Current monitor In preparation for The plurality of output beam current values are maintained at a constant value.
Select part or all of the first AC power amplifier and
Feedback 4. The method according to claim 1, wherein
A beam emitting device according to any of the preceding claims. 6.The output of the output beam current monitor is
Analog / digital converter for analog / digital conversion
When, Input the output of the analog / digital converter and output
When the beam current value is small, increase the amplification factor.
Each frequency is controlled by a feedback control function that lowers the amplification rate.
A calculator for calculating the amplification factor for each, Digital-to-analog conversion of the output of the computer
The first AC power amplifier or the second AC power amplifier
And a digital / analog converter for input. This
The beam emitting device according to claim 4 or 5, wherein
Place. 7.The output of the output beam current monitor is input.
Force the analog device to control the feedback control function.
Further comprising an analog arithmetic unit for performing arithmetic, The feed of a current change of the output beam at a speed higher than a predetermined speed
Calculate the back control function with the analog computing device
And Said feed of a current change at a speed less than a predetermined value of the output beam
Calculate the back control function with the computer That
7. The beam emitting device according to claim 6, wherein: Claim 8.Accumulated beam for measuring accumulated beam current
Current monitor for An analog / digital converter for outputting the output of the storage beam current monitor
And an analog / digital converter for converting
Inputting the output of the analog / digital converter to the computer
The output beam is monitored while monitoring the stored beam current value.
8. The method according to claim 6, wherein the current value is controlled.
The beam output device according to claim 1. 9. Energy is generated by accelerating while orbiting charged particles.
Accumulate energy and use the resonance phenomenon of the charged particle beam
In a charged particle accelerator that extracts a beam by
Input AC power at a number of frequencies, thereby producing
A beam emitting device that vibrates the beam by an electric field
And having two electrodes arranged to sandwich the beam,
Betatron to betatron oscillation amplitude of the beam
Multiple frequencies distributed in proportion to the absolute value of the differential value of the vibration frequency.
The wave number is input to the electrodes and the resulting electricity
Equipped with a knockout electrode that vibrates the beam by the field
A beam emitting device.