阅读说明：本技术 基于电子直线加速的伽马射线源装置 (Gamma ray source device based on electron linear acceleration ) 是由 唐传祥 杜应超 黄文会 李任恺 颜立新 陈怀璧 施嘉儒 查皓 张鸿泽 陈寒 于 2020-12-29 设计创作，主要内容包括：本发明公开了一种基于电子直线加速的伽马射线源装置,包括沿电子束直线运动方向顺次布置的：S或C波段光阴极电子枪,用于产生并发射电子束；S或C波段聚束腔,用于压缩所经过的电子束的束长；S或C波段加速管,用于冻结所经过的电子束的束长和发射度；X波段加速管组,用于加速所经过的电子束；四极透镜组,用于聚焦所经过的电子束；作用室,用于将进入其中的散射激光和电子束进行逆康普顿散射以产生伽马射线。本发明的基于电子直线加速的伽马射线源装置,实现了伽马射线源的小型化,缩减了空间占用,并且所产生的伽马射线具有大范围、准单能的特点,从而满足了多种场景中的灵活应用,可满足乏燃料的检测和物品安检等方面的需求。(The invention discloses a gamma ray source device based on electron linear acceleration, which comprises the following components in sequence along the linear motion direction of an electron beam: the S or C wave band photocathode electron gun is used for generating and emitting electron beams; the S or C wave band beam focusing cavity is used for compressing the beam length of the passing electron beam; the S or C wave band accelerating tube is used for freezing the beam length and the emittance of the passing electron beam; an X-band accelerating tube group for accelerating the passing electron beam; a quadrupole lens group for focusing the passing electron beam; and the action chamber is used for carrying out inverse Compton scattering on the scattered laser and the electron beam entering the action chamber so as to generate gamma rays. The gamma ray source device based on the electronic linear acceleration realizes the miniaturization of the gamma ray source, reduces the space occupation, and the generated gamma rays have the characteristics of large range and quasi-unienergy, thereby meeting the flexible application in various scenes and meeting the requirements of the detection of spent fuel, the safety inspection of articles and the like.)

1. A gamma ray source device based on electron linear acceleration is characterized by comprising the following components which are sequentially arranged along the linear motion direction of an electron beam:

the S or C waveband photocathode electron gun is used for generating and emitting the electron beam;

an S or C band bunching cavity for compressing the beam length of the passing electron beam;

the S or C wave band accelerating tube is used for freezing the beam length and the emittance of the passing electron beam;

an X-band accelerating tube group for accelerating or decelerating the passing electron beam;

a quadrupole lens set for focusing the electron beam passing therethrough;

an action chamber for inverse compton scattering of the scattered laser light and the electron beam entering therein to produce gamma rays.

2. The electron linear acceleration-based gamma ray source device of claim 1, further comprising:

an electron gun solenoid mounted at an electron beam exit of the S or C band photo cathode electron gun to adjust a beam spot envelope and emittance of a passing electron beam bunch.

3. The electron linear acceleration-based gamma ray source device of claim 1, further comprising:

the accelerating tube solenoid is wound on the S or C wave band accelerating tube so as to control the beam spot envelope and the emittance of the electron beam in the S or C wave band accelerating tube.

4. The electron linear acceleration-based gamma ray source device according to any one of claims 1 to 3, wherein:

the length of the S or C wave band accelerating tube is 0.8 to 2.5 meters.

5. The electron linear acceleration-based gamma ray source device according to any one of claims 1 to 3, wherein:

the X-band accelerating tube group comprises at least one X-band accelerating tube which is sequentially arranged along the linear motion direction of the electron beam.

6. The electron linear acceleration-based gamma ray source device of claim 5, wherein:

the length of each X-waveband accelerating tube is 0.4-1.5 m.

7. The electron linear acceleration-based gamma ray source device of claim 5, wherein:

the average acceleration gradient of the X-waveband acceleration tube to the electron beam is not less than 60 MV/m.

8. The electron linear acceleration-based gamma ray source device according to any one of claims 1 to 3, wherein:

the number of the quadrupole lens groups is at least one, and when the number of the quadrupole lens groups is at least two, the at least two quadrupole lens groups are sequentially arranged along the linear motion direction of the electron beams.

9. The electron linear acceleration-based gamma ray source device according to any one of claims 1 to 3, characterized by further comprising:

a scattered laser system for generating the scattered laser light; and the number of the first and second groups,

a laser introduction system for introducing scattered laser light generated by the scattered laser system into the action chamber.

Technical Field

The invention relates to a gamma ray source, in particular to a gamma ray source device based on electron linear acceleration.

Background

Gamma ray is an electromagnetic wave with the highest frequency, and has high photon energy and extremely strong penetrating power. Natural gamma sources are mainly from secondary radiation from the interaction of cosmic ray particles with the atmosphere, and gamma decay of radioisotopes in nature. The artificial gamma ray is mainly generated based on nuclear fission, bremsstrahlung, synchrotron radiation, inverse compton scattering and the like. Compared with the common ray tube based on bremsstrahlung radiation and the gamma ray source based on a synchrotron radiation accelerator, the gamma ray source based on inverse Compton scattering has the advantages of good directivity, high brightness, short time structure, high energy, adjustability and the like, and has wide application prospects in radiation imaging, ultrafast physical process research and medical physical research.

However, the existing inverse compton scattering gamma ray device based on a storage ring and a high-energy accelerator is usually hundreds of meters in length due to different accelerator principles or limitation of acceleration technology, so that the device is difficult to be compact and cannot be moved flexibly, and further, the existing gamma ray source is not enough to support the research of gamma ray imaging and nuclear resonance fluorescence of special scenes such as nuclear waste diagnosis and the like.

Therefore, how to miniaturize the gamma ray source to achieve small space occupation and flexibly apply to various scenes becomes a problem to be solved urgently.

Disclosure of Invention

In view of this, the present invention provides a gamma ray source device based on electron linear acceleration, so as to achieve miniaturization of the gamma ray source, reduce space occupation, and achieve flexible application in various scenes.

The technical scheme of the invention is realized as follows:

a gamma ray source device based on electron linear acceleration comprises the following components arranged in sequence along the linear movement direction of an electron beam:

the S or C waveband photocathode electron gun is used for generating and emitting the electron beam;

an S or C band bunching cavity for compressing the beam length of the passing electron beam;

the S or C wave band accelerating tube is used for freezing the beam length and the emittance of the passing electron beam;

an X-band accelerating tube group for accelerating or decelerating the passing electron beam;

a quadrupole lens set for focusing the electron beam passing therethrough;

an action chamber for inverse compton scattering of the scattered laser light and the electron beam entering therein to produce gamma rays.

Further, the gamma ray source device based on electron linear acceleration further comprises:

an electron gun solenoid mounted at an electron beam exit of the S or C band photo cathode electron gun to adjust a beam spot envelope and emittance of a passing electron beam bunch.

Further, the gamma ray source device based on electron linear acceleration further comprises:

the accelerating tube solenoid is wound on the S or C wave band accelerating tube so as to adjust the beam spot envelope and the emittance of the electron beam in the S or C wave band accelerating tube.

Further, the length of the S or C wave band accelerating tube is 0.8 to 2.5 meters.

Further, the X-band accelerating tube group comprises at least one X-band accelerating tube which is sequentially arranged along the linear motion direction of the electron beam.

Further, the length of each X-band accelerating tube is 0.4-1.5 m.

Further, the average acceleration gradient of the X-band accelerating tube to the electron beam is not less than 60 MV/m.

Further, the number of the quadrupole lens groups is at least one, and when the number of the quadrupole lens groups is at least two, the at least two quadrupole lens groups are sequentially arranged along the linear motion direction of the electron beams.

Further, the gamma ray source device based on electron linear acceleration further comprises:

a scattered laser system for generating the scattered laser light; and the number of the first and second groups,

a laser introduction system for introducing scattered laser light generated by the scattered laser system into the action chamber.

According to the scheme, the gamma ray source device based on the electronic linear acceleration can control the occupied space of the total length direction of the gamma ray source device, meanwhile, the large-range coverage of the photon energy of the gamma ray can be realized, the gamma ray with the quasi-single energy can be obtained, the gamma ray source is miniaturized, the occupied space is reduced, and the generated gamma ray has the characteristics of large range and quasi-single energy, so that the device can be flexibly applied to various scenes, and the requirements of the detection of spent fuel, the safety inspection of articles and the like can be met.

Drawings

Fig. 1 is a schematic structural diagram of a gamma ray source device based on electron linear acceleration according to an embodiment of the present invention.

In the drawings, the names of the components represented by the respective reference numerals are as follows:

1. s or C wave band photocathode electron gun

11. Electron gun solenoid

2. S or C wave band beam-focusing cavity

3. S or C wave band accelerating tube

31. Accelerating tube solenoid

4. X-waveband accelerating tube group

41. X-waveband accelerating tube

5. Quadrupole lens group

6. Action chamber

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and examples.

As shown in fig. 1, the gamma ray source device based on electron linear acceleration according to the embodiment of the present invention mainly includes an S or C band photocathode electron gun 1, an S or C band beam focusing cavity 2, an S or C band accelerating tube 3, an X band accelerating tube group 4, a quadrupole lens group 5 and an action chamber 6, which are sequentially arranged along the linear moving direction of an electron beam. Wherein the S or C band photocathode electron gun 1 is used for generating and emitting electron beams. The S-or C-band beaming chamber 2 is used to compress the beam length of the passing electron beam. The S or C band accelerating tube 3 is used to freeze the beam length and emittance of the passing electron beam so that the beam length and emittance of the electron beam do not change any more. The X-band acceleration tube group 4 is used to accelerate the passing electron beam. The quadrupole lens group 5 is used to focus the passing electron beam. The action chamber 6 is used for carrying out inverse Compton scattering on the scattered laser and the electron beam entering the action chamber so as to generate gamma rays.

Wherein freezing means that the beam length and emittance of the electron beam are not changed any more. Where emittance is a property of a charged particle beam cluster in a particle accelerator. Emittance is a measure of the average spread of a charged particle (e.g. electron) beam cluster in a phase space composed of position and momentum, in units of length m or mm. Where the phase space of position and momentum refers to the space of all possible states of the system, each possible position and momentum state of a dotted particle corresponds to a unique point in the phase space.

The S or C band, i.e., the S band or the C band, refers to a part of a microwave band in the electromagnetic spectrum, and the coverage range is 2GHz to 4GHz, and the C band refers to a part of a microwave band in the electromagnetic spectrum, and the coverage range is 4GHz to 8 GHz. Wherein, the X wave band refers to a part of a microwave frequency band in an electromagnetic wave spectrum, and the coverage range is 8GHz to 12 GHz.

In an alternative embodiment, as shown in fig. 1, the electron linear acceleration-based gamma ray source apparatus of the embodiment of the present invention further comprises an electron gun solenoid 11. An electron gun solenoid 11 is installed at the electron beam outlet of the S or C band photocathode electron gun 1 to adjust the beam spot envelope and emittance of the passing electron beam bunch.

Wherein, the beam spot envelope is a physical quantity describing the spatial lateral distribution of the electron beam bunch, and refers to the maximum size of the lateral distribution of the electron beam bunch.

In an alternative embodiment, as shown in fig. 1, the electron linear acceleration-based gamma ray source apparatus of the embodiment of the present invention further includes an acceleration tube solenoid 31. The accelerating tube solenoid 31 is wound around the S-band or C-band accelerating tube 3 to adjust the beam spot envelope and emittance of the electron beam in the S-band or C-band accelerating tube 3.

In an alternative embodiment, the length of the S-or C-band accelerating tube 3 is 0.8 to 2.5 meters. In the preferred embodiment, the length of the S or C band accelerating tube 3 is 1.5 meters.

As shown in fig. 1, in an alternative embodiment, the X-band acceleration tube group 4 includes at least one X-band acceleration tube 41 arranged in sequence along the direction of linear movement of the electron beam.

In an alternative embodiment, each X-band accelerating tube 41 has a length of 0.4 meters to 1.5 meters. Preferably, each X-band accelerating tube 41 has a length of 0.7 meters.

In an alternative embodiment, the average acceleration gradient of the X-band acceleration tube 41 to the electron beam is not less than 60MV/m (megavolts/meter).

In the preferred embodiment, the number of X-band accelerating tubes 41 is 6, and each X-band accelerating tube 41 has a length of 0.7 meters. In this case, the X-band acceleration tube group 4 may be controlled within a range of 5.5 m long including a gap reserved between the adjacent X-band acceleration tubes 41, and the energy of the electron beam may be increased by more than 300MeV (mega electron volts) within the X-band acceleration tube group 4 having a length of 5 m in a case where the average acceleration gradient of each X-band acceleration tube 41 with respect to the electron beam is not less than 80 MV/m.

As shown in fig. 1, the number of the quadrupole lens groups 5 is at least one, and when there are at least two quadrupole lens groups 5, at least two quadrupole lens groups 5 are sequentially arranged in the linear movement direction of the electron beam. In the preferred embodiment, the number of quadrupole lens sets 5 is four.

In an alternative embodiment, the gamma ray source device based on electron linear acceleration according to the embodiment of the present invention further includes a scattering laser system and a laser introduction system (not shown in the figure). Wherein the scattered laser system is used for generating scattered laser light. The laser introducing system is used for introducing scattered laser light generated by the scattered laser system into the action chamber 6, so that the scattered laser light and the electron beam realize front collision in the action chamber 6 and generate gamma rays under the inverse Compton scattering effect.

The gamma ray source device based on electron linear acceleration has a compact structure, the total length of the device can be controlled to be about 12 meters in optional embodiments, the energy range of the generated gamma ray photons can cover 0.2MeV to 4.8MeV, the bandwidth is less than 1.5% rms (root mean square), and the total yield of the gamma ray photons is more than 10⁸Wherein the bandwidth is less than 1.5% rms, i.e. the root mean square bandwidth is less than 1.5%.

To achieve high gradients in the acceleration structure, in an alternative embodiment, a pulse compressor may be used to pulse compress the klystron (the device that provides microwave power to the X-band accelerator tube) power.

The gamma ray source device based on electron linear acceleration adopts a mode of mixing and accelerating an S or C waveband photocathode injector (comprising an S or C waveband photocathode electron gun 1, an electron gun solenoid 11, an S or C waveband beam focusing cavity 2, an S or C waveband accelerating tube 3 and an accelerating tube solenoid 31) and an X waveband accelerating tube, and can realize extremely high brightness of electron beams while keeping the device compact by optimizing the position of an accelerating structure and other beam parameters. The charge of the electron beam cluster is more than 200pC (Piculomb), the normalized emittance of the electron beam is less than 0.6mm mrad (millimeter milliradian), the electron beam cluster length is less than 2ps rms (picosecond root mean square), and the electron beam cluster energy dispersion is less than 0.3% rms (namely, the electron beam cluster root mean square length is less than 2ps, and the electron beam cluster root mean square energy dispersion is less than 0.3%).

The gamma ray source device based on electron linear acceleration can realize the large-range coverage of the photon energy of the gamma ray by adopting two operation modes of frequency doubling and frequency non-doubling of 800nm (nanometer) scattering laser, wherein the two operation modes comprise 0.2MeV to 4.8 MeV.

According to the gamma ray source device based on electron linear acceleration, the quasi-monoenergetic of the gamma ray (the monoenergetic means that the energy is the same, and the quasi-monoenergetic of the gamma ray means that all photons in the gamma ray are almost at the same energy) is realized by combining the optimization of laser bandwidth and beam current energy dispersion through a collimation hole beam selection scheme, and the bandwidth is less than 1.5% rms.

The gamma ray source device based on electron linear acceleration can control the polarization state of gamma ray photons by controlling the polarization state of scattered laser, and realize continuous adjustment from 100% linear polarization to circular polarization.

By adopting the gamma ray source device based on electron linear acceleration, the gamma ray photon energy can be adjusted in a large range by adjusting the acceleration gradient and the phase of the X-waveband accelerating tube, the large-range coverage of the gamma ray photon energy is realized, the gamma ray with quasi-single energy can be obtained, the gamma ray source is miniaturized, the space occupation is reduced, and the generated gamma ray has the characteristics of large range and quasi-single energy, so that the device meets the flexible application in various scenes, and can meet the requirements of spent fuel detection, article safety inspection and the like.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.