真空強場環(huán)境耐電子轟擊材料優(yōu)選研究
發(fā)布時間：2018-12-19 13:58
【摘要】：相對論返波管(RBWO)具有高功率、高效率、適合重復(fù)頻率工作等特點,是目前最有發(fā)展?jié)摿Φ母吖β饰⒉?HPM)器件之一。然而,強電磁場真空擊穿引起的輸出微波功率下降、脈寬縮短以及結(jié)構(gòu)損傷帶來的壽命等問題,嚴(yán)重限制了RBWO的輸出能量,影響了其實用化進程。本論文基于“陽極”擊穿模型,開展了耐電子轟擊材料的優(yōu)選研究。論文的研究成果如下:(1)結(jié)合經(jīng)典Monte-Carlo方法和Bethe能量損失規(guī)律,研究了MeV級電子垂直入射Cu、SS304和TA2三種常見金屬靶材的能量損失規(guī)律。研究表明,材料原子序數(shù)和原子密度越小,電子在材料中的有效射程越長,單位體積內(nèi)沉積的平均能量越低,越有利于材料耐受高能電子轟擊。綜合金屬材料達到熔融燒蝕的臨界條件,給出了耐電子轟擊材料優(yōu)選原則:密度小、熔點高和比熱容大。(2)采用環(huán)形電子束打靶實驗比較了Cu、SS304和TA2三種材料的耐電子轟擊性能,在相同的電子束能量下,Cu因密度高、熔點低和比熱容小而更容易受到電子束轟擊破壞。相對而言,密度低、熔點高和比熱容大的TA2材料具有更好的耐電子束轟擊性能。實驗結(jié)果初步驗證了耐電子束轟擊材料的優(yōu)選原則。(3)采用CST軟件模擬設(shè)計了場強1.8 MV/cm的波導(dǎo)測試腔,單個腔內(nèi)兩側(cè)場分布非對稱,以將材料的電子發(fā)射和轟擊性能分開研究,進一步明確“陽極”機制引起的強電磁場真空擊穿模型。在1 T外加引導(dǎo)磁場下,SS304材料測試腔強電磁場真空擊穿可以將脈寬由25.2 ns縮短至15.6 ns,縮短約38%,輸出微波功率由2.06 GW減小至1.78 GW,減幅約13.6%。與SS304材料相比,轟擊側(cè)采用耐受電子轟擊的TA2材料可以將脈寬提高約3.8 ns,功率增加約0.14 GW。(4)在1 T外加引導(dǎo)磁場下,整腔鈦材料與SS304材料相比,TC18性能最佳,可以將脈寬由15.6 ns增加到24.8 ns,功率由1.78 GW增加到2.04 GW,實驗結(jié)果表明,耐電子束轟擊性能更優(yōu)的鈦材料,可以有效緩解強場真空擊穿引起的脈寬縮短和功率下降等問題。其優(yōu)異性能是由于存在的α相晶粒細(xì)小能夠強化晶體結(jié)構(gòu),延緩裂紋形核,提高了TC18材料的耐電子轟擊性能;同時,發(fā)射性能也有所改善。本論文在理論分析和數(shù)值計算的基礎(chǔ)上,給出了強場真空環(huán)境下耐電子轟擊材料的優(yōu)選原則,相關(guān)研究結(jié)果可為RBWO結(jié)構(gòu)中的材料優(yōu)選提供支撐,同時可為RBWO中強電磁場真空擊穿機理分析提供一定參考。
[Abstract]:Relativistic backward-wave tube (RBWO) is one of the most promising high-power microwave (HPM) devices due to its high power, high efficiency and suitable repetition rate. However, the output microwave power is decreased, the pulse width is shortened, and the lifetime caused by structural damage is reduced due to the vacuum breakdown of strong electromagnetic field, which seriously limits the output energy of RBWO and affects its practical process. Based on the anodic breakdown model, the selection of electronic bombardment resistant materials is studied in this paper. The research results are as follows: (1) combined with the classical Monte-Carlo method and the Bethe energy loss law, the energy loss laws of three common metal targets, Cu,SS304 and TA2, are studied. The results show that the smaller the atomic number and density, the longer the effective range of electrons in the material, and the lower the average energy deposited in the unit volume, which is more favorable to resist the high-energy electron bombardment. In order to meet the critical condition of melting ablation, the optimum selection principle of electron bombardment resistant materials is given: low density, high melting point and high specific heat capacity. (2) Cu, is compared with ring electron beam shooting experiment. Under the same electron beam energy, SS304 and TA2 are more vulnerable to electron beam bombardment because of their high density, low melting point and low specific heat capacity. Comparatively speaking, the TA2 materials with low density, high melting point and high specific heat capacity have better resistance to electron beam bombardment. The experimental results preliminarily verify the principle of optimal selection of materials resistant to electron beam bombardment. (3) the waveguide test cavity with a field strength of 1.8 MV/cm is designed by using CST software, and the field distribution on both sides of a single cavity is asymmetric. In order to study the electron emission and bombardment performance of materials separately, the vacuum breakdown model of strong electromagnetic field caused by "anode" mechanism is further clarified. At 1 T external magnetic field, the vacuum breakdown of SS304 material with strong electromagnetic field can shorten the pulse width from 25.2 ns to 15.6 ns, and the output microwave power from 2.06 GW to 1.78 GW,. Compared with SS304 material, the pulse width of TA2 material with electron bombardment resistance can be increased by about 3.8 ns, power by 0.14 GW. (4). Compared with SS304 material, the whole cavity titanium material has the best performance compared with SS304 material under 1 T external guiding magnetic field. The pulse width can be increased from 15. 6 ns to 24. 8 ns, power from 1. 78 GW to 2. 04 GW,. The experimental results show that the titanium material with better resistance to electron beam bombardment can be obtained. It can effectively alleviate the problems of shortening pulse width and decreasing power caused by strong field vacuum breakdown. The excellent properties are that the fine 偽 phase grains can strengthen the crystal structure, delay the nucleation of cracks, and improve the electron bombardment resistance of TC18 materials, and the emission properties are also improved. On the basis of theoretical analysis and numerical calculation, this paper presents the optimal selection principle of electron-resistant materials in strong field vacuum environment. The related research results can provide support for material selection in RBWO structures. At the same time, it can provide some reference for the analysis of vacuum breakdown mechanism of RBWO.
【學(xué)位授予單位】：湘潭大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TN125
本文編號：2387020
[Abstract]:Relativistic backward-wave tube (RBWO) is one of the most promising high-power microwave (HPM) devices due to its high power, high efficiency and suitable repetition rate. However, the output microwave power is decreased, the pulse width is shortened, and the lifetime caused by structural damage is reduced due to the vacuum breakdown of strong electromagnetic field, which seriously limits the output energy of RBWO and affects its practical process. Based on the anodic breakdown model, the selection of electronic bombardment resistant materials is studied in this paper. The research results are as follows: (1) combined with the classical Monte-Carlo method and the Bethe energy loss law, the energy loss laws of three common metal targets, Cu,SS304 and TA2, are studied. The results show that the smaller the atomic number and density, the longer the effective range of electrons in the material, and the lower the average energy deposited in the unit volume, which is more favorable to resist the high-energy electron bombardment. In order to meet the critical condition of melting ablation, the optimum selection principle of electron bombardment resistant materials is given: low density, high melting point and high specific heat capacity. (2) Cu, is compared with ring electron beam shooting experiment. Under the same electron beam energy, SS304 and TA2 are more vulnerable to electron beam bombardment because of their high density, low melting point and low specific heat capacity. Comparatively speaking, the TA2 materials with low density, high melting point and high specific heat capacity have better resistance to electron beam bombardment. The experimental results preliminarily verify the principle of optimal selection of materials resistant to electron beam bombardment. (3) the waveguide test cavity with a field strength of 1.8 MV/cm is designed by using CST software, and the field distribution on both sides of a single cavity is asymmetric. In order to study the electron emission and bombardment performance of materials separately, the vacuum breakdown model of strong electromagnetic field caused by "anode" mechanism is further clarified. At 1 T external magnetic field, the vacuum breakdown of SS304 material with strong electromagnetic field can shorten the pulse width from 25.2 ns to 15.6 ns, and the output microwave power from 2.06 GW to 1.78 GW,. Compared with SS304 material, the pulse width of TA2 material with electron bombardment resistance can be increased by about 3.8 ns, power by 0.14 GW. (4). Compared with SS304 material, the whole cavity titanium material has the best performance compared with SS304 material under 1 T external guiding magnetic field. The pulse width can be increased from 15. 6 ns to 24. 8 ns, power from 1. 78 GW to 2. 04 GW,. The experimental results show that the titanium material with better resistance to electron beam bombardment can be obtained. It can effectively alleviate the problems of shortening pulse width and decreasing power caused by strong field vacuum breakdown. The excellent properties are that the fine 偽 phase grains can strengthen the crystal structure, delay the nucleation of cracks, and improve the electron bombardment resistance of TC18 materials, and the emission properties are also improved. On the basis of theoretical analysis and numerical calculation, this paper presents the optimal selection principle of electron-resistant materials in strong field vacuum environment. The related research results can provide support for material selection in RBWO structures. At the same time, it can provide some reference for the analysis of vacuum breakdown mechanism of RBWO.
【學(xué)位授予單位】：湘潭大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TN125
【參考文獻】
相關(guān)期刊論文 前1條
1 靳振興;張軍;楊建華;鐘輝煌;錢寶良;舒挺;張建德;周生岳;許流榮;;S波段長脈沖相對論返波振蕩器實驗研究[J];強激光與粒子束;2010年11期
相關(guān)碩士學(xué)位論文 前1條
1 張章;高功率微波源中脈沖縮短現(xiàn)象的粒子模擬與機理研究[D];電子科技大學(xué);2004年
，本文編號：2387020
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