阅读说明：本技术 一种辐照加速器及其束流辐照均匀度的调整方法 (Irradiation accelerator and beam irradiation uniformity adjusting method thereof ) 是由 王凤涛 谭松清 高宁 黄敬松 单云 王复涛 封淼伟 赵平 叶斌 徐粒峰 于 2021-02-09 设计创作，主要内容包括：本发明公开了一种辐照加速器及其束流辐照均匀度的调整方法,属于电子辐照加速器技术领域。包括：通过改变磁场扫描频率f0和束流脉冲频率f1来计算得出标准差,以及钛膜风冷装置的出风口设置于钛膜的一侧,出风口的长度与钛膜的一侧长度相等,且出风口与进风口之间的连通管路设置有若干段弯折部件。该辐照加速器及其束流辐照均匀度的调整方法,使辐照均匀度较好,且能够延长钛膜的使用寿命。(The invention discloses an irradiation accelerator and a method for adjusting beam irradiation uniformity thereof, and belongs to the technical field of electron irradiation accelerators. The method comprises the following steps: the standard deviation is calculated by changing the magnetic field scanning frequency f0 and the beam pulse frequency f1, the air outlet of the titanium film air cooling device is arranged on one side of the titanium film, the length of the air outlet is equal to that of one side of the titanium film, and a plurality of sections of bending parts are arranged on a communication pipeline between the air outlet and the air inlet. The irradiation accelerator and the method for adjusting the beam irradiation uniformity thereof have the advantages that the irradiation uniformity is better, and the service life of a titanium film can be prolonged.)

1. A method for adjusting beam irradiation uniformity of an irradiation accelerator is characterized by comprising the following steps:

s1, determining the change interval of the scanning magnetic field intensity B according to the size specification of the titanium window;

s2, the size of the titanium window along the first direction is L, the titanium window is evenly divided into n beam pulse areas along the first direction, and the size of each beam pulse area along the first direction is L/n;

s3, setting the magnetic field scanning frequency to be f0, shooting the beam pulse with the given beam pulse frequency to be f1 to the titanium window, obtaining the number of beam pulses in each beam pulse area, and calculating the initial standard deviation or variance of the number of beam pulses in the n beam pulse areas;

s4, the number of beam pulses in each beam pulse area is obtained again by changing the magnetic field scanning frequency f0 and/or the beam pulse frequency f1, and the adjustment standard deviation or variance of the number of beam pulses in the n beam pulse areas is calculated again;

and S5, when the value of the adjusted standard deviation or variance is smaller than the value of the initial standard deviation or variance, recording the magnetic field scanning frequency f0 and the beam pulse frequency f1 corresponding to the adjusted standard deviation or variance.

2. The method as claimed in claim 1, further comprising S6, selecting the combination of the magnetic field scanning frequency f0 and the beam pulse frequency f1 corresponding to the adjustment standard deviation or variance with the smallest value from all the adjustment standard deviations or variances with values smaller than the initial standard deviation or variance.

3. The method of claim 1, wherein the beam pulse is directed to an edge position of the titanium window in the first direction when the magnetic field strength B reaches a maximum value.

4. The method of adjusting uniformity of beam irradiation of an irradiation accelerator according to claim 1, wherein the number of beam pulses in each of the beam pulse regions is calculated by computer simulation in S3 and S4.

5. An irradiation accelerator, comprising:

the irradiation box is arranged in a frustum shape, a beam inlet is formed in the top of the irradiation box, a beam outlet is formed in the bottom of the irradiation box, and the beam inlet and the beam outlet are arranged oppositely;

the plurality of irradiation box reinforcing ribs are arranged on the outer side wall of the irradiation box;

the vacuum flange is arranged at the beam inlet and is connected with the corrugated pipe;

the irradiation box long flange is arranged at the beam outlet;

the pressing flange plate is connected with the long flange of the irradiation box;

the titanium film is arranged between the irradiation box long flange and the compression flange plate;

the air cooling device comprises a titanium film air cooling device, wherein an air outlet of the titanium film air cooling device is formed in one side of the titanium film, the length of the air outlet is equal to that of one side of the titanium film, and a plurality of sections of bending parts are arranged on a communication pipeline between the air outlet and an air inlet.

6. The radiation accelerator of claim 1, wherein the opposite sides of the radiation box are isosceles trapezoids, and the cross section of the internal channel of the radiation box is gradually increased from top to bottom.

7. The irradiation accelerator as claimed in claim 6, wherein a plurality of said radiation box ribs are disposed in parallel on the outer side of the isosceles trapezoid-shaped side surface.

8. The radiation accelerator of claim 7, wherein the distance between two adjacent radiation box ribs near the beam outlet is smaller than the distance between two adjacent radiation box ribs near the beam inlet.

9. The irradiation accelerator according to claim 1, wherein the air outlet is flat, and a plurality of air guiding plates are disposed along an air outlet direction of the air outlet.

10. The irradiation accelerator according to claim 1, further comprising a fan, wherein the fan is disposed at the air inlet, a filtering device is disposed at the air inlet, and a shielding structure is disposed between the fan and the irradiation box.

Technical Field

The invention relates to the technical field of electron irradiation accelerators, in particular to an irradiation accelerator and a method for adjusting beam irradiation uniformity of the irradiation accelerator.

Background

At present, the irradiation accelerator is widely applied to the processing fields of irradiation sterilization, food preservation, material modification and the like, and has the advantages of outstanding irradiation sterilization effect and high treatment efficiency. The irradiation accelerator has the advantages that the electron accelerator is arranged in a vacuum environment, the irradiation product is arranged in an atmospheric environment, in order to ensure that the electron beam can normally irradiate the goods, a titanium film is required to be arranged at an outlet of an irradiation box of the irradiation accelerator, the titanium film can meet the requirement of the internal vacuum degree of the accelerator and can normally penetrate through the electron beam, but the titanium film is easy to heat due to long working time and is easy to damage if the titanium film is cooled in time.

In addition, industrial electron irradiation accelerators generally scan the electron beam with a triangular wave scanning magnetic field in order to make the electron beam more uniformly irradiated on a product. However, the scanning frequency and the pulse frequency of the beam can affect the uniformity of the beam irradiation on the product, and the irradiation uniformity of the current irradiation accelerator is poor, so that the difference of the sterilization effect of each part of the product to be irradiated is large.

Disclosure of Invention

Aiming at the problems in the prior art, the invention aims to provide the irradiation accelerator and the method for adjusting the beam irradiation uniformity thereof, so that the irradiation uniformity of the irradiation accelerator is better, and the service life of a titanium film can be prolonged.

The specific technical scheme is as follows:

a method for adjusting beam irradiation uniformity of an irradiation accelerator mainly comprises the following steps:

s1, determining the change interval of the scanning magnetic field intensity B according to the size specification of the titanium window;

s2, the size of the titanium window along the first direction is L, the titanium window is evenly divided into n beam pulse areas along the first direction, and the size of each beam pulse area along the first direction is L/n;

s3, setting the magnetic field scanning frequency to be f0, shooting the beam pulse with the given beam pulse frequency to be f1 to a titanium window, obtaining the number of beam pulses in each beam pulse area, and calculating the initial standard deviation or variance of the number of beam pulses in the n beam pulse areas;

s4, the beam pulse number in each beam pulse area is obtained again by changing the magnetic field scanning frequency f0 and/or the beam pulse frequency f1, and the adjustment standard deviation or variance of the beam pulse number in the n beam pulse areas is calculated again;

and S5, when the value of the adjusted standard deviation or variance is smaller than the value of the initial standard deviation or variance, recording the magnetic field scanning frequency f0 and the beam pulse frequency f1 corresponding to the adjusted standard deviation or variance.

The method for adjusting the uniformity of beam irradiation of the irradiation accelerator is further characterized by further comprising the step of S6, and selecting the combination of the magnetic field scanning frequency f0 and the beam pulse frequency f1 corresponding to the adjustment standard deviation or variance with the minimum value from all the adjustment standard deviations or variances with the values smaller than the initial standard deviation or variance.

The method for adjusting the beam irradiation uniformity of the irradiation accelerator is further characterized in that when the magnetic field intensity B reaches the maximum value, beam pulses are shot to the edge position of the titanium window along the first direction.

The method for adjusting the uniformity of beam irradiation of the irradiation accelerator described above is further characterized in that the number of beam pulses in each beam pulse region is calculated by computer simulation in S3 and S4.

An irradiation accelerator, comprising essentially: the device comprises an irradiation box, a plurality of irradiation box reinforcing ribs, a vacuum flange, an irradiation box long flange, a pressing flange plate, a titanium film and a titanium film air cooling device.

The irradiation box is arranged in a frustum shape, a beam inlet is formed in the top of the irradiation box, a beam outlet is formed in the bottom of the irradiation box, and the beam inlet and the beam outlet are arranged oppositely; the plurality of irradiation box reinforcing ribs are arranged on the outer side wall of the irradiation box; the vacuum flange is arranged at the beam inlet and connected with the corrugated pipe; the long flange of the irradiation box is arranged at the beam outlet; the pressing flange plate is connected with the long flange of the irradiation box; the titanium film is arranged between the long flange of the irradiation box and the pressing flange plate.

The air outlet of the titanium film air cooling device is arranged on one side of the titanium film, the length of the air outlet is equal to that of one side of the titanium film, and a plurality of sections of bending parts are arranged on a communication pipeline between the air outlet and the air inlet.

The irradiation accelerator is characterized in that two opposite side surfaces of the irradiation box are in isosceles trapezoid arrangement, and the cross section of the internal channel of the irradiation box is gradually increased from the top to the bottom.

The irradiation accelerator is characterized in that the plurality of irradiation box reinforcing ribs are arranged on the outer side of the side face in the shape of the isosceles trapezoid in parallel.

The irradiation accelerator is also characterized in that the distance between two adjacent irradiation box reinforcing ribs close to the beam outlet is smaller than the distance between two adjacent irradiation box reinforcing ribs close to the beam inlet.

The irradiation accelerator is characterized in that the air outlet is flat, and a plurality of air guide sheets are arranged along the air outlet direction of the air outlet.

The irradiation accelerator is characterized by further comprising a fan, wherein the fan is arranged at the air inlet, a filtering device is arranged at the air inlet, and a shielding structure is arranged between the fan and the irradiation box.

The positive effects of the technical scheme are as follows:

in the irradiation accelerator and the method for adjusting the beam irradiation uniformity of the irradiation accelerator, the corresponding magnetic field scanning frequency f0 and beam pulse frequency f1 with better irradiation uniformity are obtained by calculating the standard deviation, and the irradiation uniformity of a product to be irradiated is further improved by adopting the values; and a titanium film air cooling device is arranged on one side of the irradiation box to cool the titanium film timely and uniformly so as to prolong the service life of the titanium film.

Drawings

FIG. 1 is a schematic structural diagram of an embodiment of a radiation accelerator of the present invention;

FIG. 2 is a cross-sectional view taken at A-A of FIG. 1;

FIG. 3 is an enlarged view of a portion of FIG. 2 at B;

FIG. 4 is a perspective view of an embodiment of a radiation accelerator of the present invention;

fig. 5 is a schematic diagram of the variation of the scanning magnetic field strength B with time in an irradiation accelerator according to the present invention.

1. An irradiation box; 2. an irradiation box reinforcing rib; 3. a vacuum flange; 4. a long flange of the irradiation box; 5. compressing the flange plate; 6. and (5) a titanium film.

Detailed Description

In order to make the technical means, the creation features, the achievement purposes and the effects of the invention easy to understand, the following embodiments are specifically described with reference to fig. 1 to 4.

The numbering of the components themselves, such as "first", "second", etc., is used herein only to distinguish between the objects depicted and not to have any sequential or technical meaning. The term "connected" and "coupled" when used in this application, unless otherwise indicated, includes both direct and indirect connections (couplings). In the description of the present invention, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention.

In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

In the method for adjusting the beam irradiation uniformity of the irradiation accelerator,

s1, determining a change interval of the scanning magnetic field intensity B according to the size specification of the titanium window, wherein the larger the size specification of the titanium window is, the larger the required scanning magnetic field intensity B is, the size specification of the titanium window generally refers to the length of the titanium window, and the titanium window is formed by clamping a titanium film through a long flange of an irradiation box and a compression flange plate.

S2, the size of the titanium window along the first direction is L, the titanium window is evenly divided into n beam pulse areas along the first direction, the size of each beam pulse area along the first direction is L/n, and the preferred first direction is the length direction of the titanium window;

s3, setting the magnetic field scanning frequency to be f0, wherein the range of f0 is generally 10-600Hz, shooting the beam pulse with the given beam pulse frequency of f1 to a titanium window, wherein the range of f1 is generally 10-1000Hz, obtaining the number of the beam pulse in each beam pulse area, calculating the initial standard deviation or variance of the number of the beam pulses in n beam pulse areas, and generally preferably adopting the standard deviation;

s4, changing the magnetic field scanning frequency f0 and/or the beam pulse frequency f1, wherein the magnetic field scanning frequency f0 is unchanged, and the beam pulse frequency f1 is changed; or the beam pulse frequency f1 is unchanged, and the magnetic field scanning frequency f0 is changed; or the magnetic field scanning frequency f0 and the beam pulse frequency f1 are changed in three ways at the same time to obtain the number of beam pulses in each beam pulse region again, and the adjustment standard deviation or variance of the number of beam pulses in n beam pulse regions is calculated again, and the standard deviation is preferably adopted generally;

and S5, when the value of the standard deviation or the variance is smaller than the value of the initial standard deviation or the variance, recording the magnetic field scanning frequency f0 and the beam pulse frequency f1 corresponding to the adjusted standard deviation or the variance, and using the magnetic field scanning frequency and the beam pulse frequency as subsequent optimization adjustment.

In a preferred embodiment, the method further comprises S6, and selecting a combination of the magnetic field scanning frequency f0 and the beam pulse frequency f1 corresponding to the adjustment standard deviation or variance with the smallest value from all the adjustment standard deviations or variances with values smaller than the initial standard deviation or variance, so that the irradiation uniformity of the product to be irradiated is better.

In a preferred embodiment, when the magnetic field strength B reaches a maximum value, the beam pulse is directed to an edge position of the titanium window along the first direction, that is, when the magnetic field strength B reaches a peak value, the beam pulse is just deflected to the edge position of the titanium window along the length direction, so that an irradiation area is prevented from being too large or too small during irradiation of the beam pulse.

In a preferred embodiment, the number of beam pulses in each beam pulse region is calculated in S3 and S4 by computer simulation, but the number of beam pulses in each beam pulse region may also be calculated by an external measuring device.

The following is a specific example for the calculation of the adjustment method:

the frequency of the triangular wave scanning magnetic field is 10Hz, the period of the triangular wave magnetic field is 0.1s, the pulse frequency of the beam is 400Hz, the length of the titanium window is 1m, and the change of the magnetic field intensity along with time is shown in figure 5:

and selecting a proper Bmax value according to the actual situation, so that the beam can just hit the edge position of the titanium window when the scanning magnetic field intensity is Bmax. The titanium window with the length of 1m is divided into 40 small segments, and the distance between every two small segments is 0.025 m. 10000 beam pulses are taken, and the pulse width of the beam pulses is ignored. The number of beam pulses of each small section on the titanium window is counted through computer simulation:

1	2	3	4	5	6	7	8	9	10
										242	246	242	246	242	246	267	245	268	366
11	12	13	14	15	16	17	18	19	20
										244	244	244	244	244	268	245	267	246	120
21	22	23	24	25	26	27	28	29	30
										273	241	249	241	273	242	248	242	272	243
31	32	33	34	35	36	37	38	39	40
										247	245	243	247	268	246	244	246	269	245

the average of this set of data was calculated to be Xbar 250

Then the standard deviation of the data is calculated according to the following formula:

the data are substituted into 29.5059 standard deviation σ.

Under the condition that the beam pulse frequency is not changed, the frequency of the triangular wave scanning magnetic field is changed to 11,12,13, … …,18,19 and 20, and the corresponding standard deviation is respectively calculated as:

scanning frequency	11	12	13	14	15	16	17	18	19	20
											Standard deviation sigma	29.14	49.46	31.45	84.66	60.59	29.24	31.27	42.59	322.47	31.7

The larger the standard deviation is, the more non-uniform the beam distribution on the titanium window is, in practical operation, the corresponding frequency combinations can be discarded, and the frequency combinations corresponding to the standard deviation lower than the initial standard deviation are retained.

For different beam pulse frequencies, the standard deviation of the beam on the titanium window can be calculated by changing the magnetic field scanning frequency through the calculation, so that whether the beam is uniform or not is judged, and the optimal or better combination of the magnetic field scanning frequency f0 and the beam pulse frequency f1 is obtained, so that the uniformity of the beam pulse on the titanium window is improved.

In the irradiation accelerator, an irradiation box 1 is arranged in a frustum shape and is in a horn mouth shape from small to large, a beam inlet is formed in the top of the irradiation box 1, a beam outlet is formed in the bottom of the irradiation box 1, the beam inlet and the beam outlet are arranged oppositely, the beam outlet is larger than the beam inlet, and beam pulses can be conveniently swept back and forth within a range; the plurality of the irradiation box reinforcing ribs 2 are arranged on the outer side wall of the irradiation box 1, and specifically, the irradiation box reinforcing ribs 2 can be arranged on the irradiation box 1 along the horizontal direction and/or the vertical direction so as to enhance the structural strength of the irradiation box 1; the vacuum flange 3 is arranged at the beam inlet and connected with the corrugated pipe, and the vacuum flange 3 is used for playing a role in vacuum sealing and preventing beam pulse leakage; the irradiation box long flange 4 is arranged at the beam outlet; the pressing flange plate 5 is connected with the long flange 4 of the irradiation box; the titanium film 6 is arranged between the irradiation box long flange 4 and the pressing flange plate 5, and the titanium film 6 is used for sealing the irradiation box 1 so as to ensure the vacuum degree inside the irradiation box 1.

The air outlet of titanium membrane air cooling device (not shown in the figure) sets up in one side of titanium membrane 6 for in time carry out cooling treatment to titanium membrane 6, in order to prolong the life of titanium membrane 6 self, the length of air outlet equals with one side length of titanium membrane 6, a plurality of position areas that the cold wind that blows out can cover titanium membrane 6 simultaneously, in order to ensure refrigerated homogeneity, and the intercommunication pipeline between air outlet and the air intake is provided with a plurality of sections bending part, prevent that the beam pulse from diffusing to the external environment through titanium membrane air cooling device, bending part has better attenuation to the beam pulse.

In a preferred embodiment, as shown in fig. 1 to 4, two opposite side surfaces of the irradiation box 1 are isosceles trapezoids, and the cross section of the internal channel of the irradiation box 1 gradually increases from the top to the bottom, so that the beam pulse can be swept back and forth in a larger range.

In a preferred embodiment, as shown in fig. 1 to 4, a plurality of irradiation box reinforcing ribs 2 are arranged in parallel on the outer side of the isosceles trapezoid-shaped side face, which has a larger area and can be used for enhancing the overall structural strength of the irradiation box 1.

In a preferred embodiment, as shown in fig. 1 to 4, the distance between two adjacent irradiation box reinforcing ribs 2 near the beam outlet is smaller than the distance between two adjacent irradiation box reinforcing ribs 2 near the beam inlet, specifically, the side surface of the irradiation box 1 gradually increases in span from top to bottom, so that the arrangement of the upper irradiation box reinforcing ribs 2 on the side surface of the irradiation box 1 is sparse, and the arrangement of the lower irradiation reinforcing ribs on the side surface of the irradiation box 1 is dense, so that the structural strength of each part of the irradiation box 1 is basically equivalent, and the structural strength is more uniform.

In a preferred embodiment, as shown in fig. 1 to 4, the air outlet (not shown) is flat, and a plurality of air guiding plates (not shown) are arranged along the air outlet direction of the air outlet, the end direction of the general air guiding plate close to the irradiation box 1 is perpendicular to the bottom side of the isosceles trapezoid side, the plurality of air guiding plates are in an involute diffusion shape, the air outlet is more uniform through the arrangement of the air guiding plates, which is beneficial to more uniform cooling of the titanium film 6, so as to prolong the service life of the titanium film 6.

In a preferred embodiment, as shown in fig. 1 to 4, the radiation box further includes a fan (not shown in the figure), the fan is disposed at the air inlet, the filter device is disposed at the air inlet to ensure that the cooling air finally blown to the titanium film 6 has no impurities, so as to avoid affecting the titanium film 6, and a shielding structure is disposed between the fan and the radiation box 1, so as to avoid affecting the normal operation of the fan due to the internal beam pulse of the radiation box 1.

The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.