EAST托卡马克电荷交换复合光谱诊断的绝对强度标定

电荷交换复合光谱(Charge e Xchange Recombination Spectroscopy,CXRS)诊断系统主要用于等离子体旋转速度和离子温度的测量。CXRS诊断的另外一个重要应用是通过测量光谱的绝对强度来确定杂质离子的密度,因此需要对系统进行绝对强度标定。在实验前通过精确校准过且各个波长强度已知的积分球光源对系统进行初步的标定;在实验过程中又利用托卡马克装置中等离子体自身产生的轫致辐射对系统的强度标定进行了进一步的检验。通过比较轫致辐射强度的实验测量值和理论计算值,可以发现两种方法得到的结果虽然存在一定的误差,但是它们的趋势是一致的。实验结果表明,利用轫致辐射进行绝对强度标定是可行的。     

贝叶斯反卷积在EAST电荷交换复合光谱分析中的应用

电荷交换复合光谱(Charge e Xchange Recombination Spectroscopy,CXRS)诊断是核聚变装置上测量等离子体离子温度和旋转速度的常规诊断之一。然而在实验中,诊断光通过光谱仪后,由于仪器函数的卷积效应,会使测量到的光谱出现明显展宽,影响数据处理的精度,所以需要对实验测量到的光谱进行反卷积处理。本文采用的反卷积方法是基于贝叶斯条件概率公式推导得出,并结合标准灯获取的仪器函数来进行反卷积,分别从仿真和实验两个方面验证了该方法的可靠性。结果表明将贝叶斯反卷积运用到先进实验超导托卡马克(Experimental Advanced Superconducting Tokamak,EAST)电荷交换复合光谱分析中,能有效提高实验测量精度。结合快速极紫外谱仪(Extreme ultraviolet,EUV),对EAST实验中经过贝叶斯反卷积后测量到的光谱进行了杂质谱线识别工作,进一步提高了精度。     

TEXT—U上电荷交换q诊断的初次结果

我们介绍ＴＥＸＴ－Ｕ新的ｑ诊断的初次结果。这种方法建立在用探测器的环形阵列去测定注入束中性粒子在二次电荷交换碰撞后被发射的平面的基础上，潜在的优点是低费用，充分的等离子体可接近性和良好的时间分辨率，我们初次的ＴＥＸＴ－Ｕ实验系列证实了定技术的可行性。     

EAST边界旋转诊断的光路分析

具有空间和时间分辨的边界旋转诊断(ERD)已在EAST装置上研制完成,经调试已投入EAST实验研究中。多道光纤的观测视线已进行位置标定,经过分析,每道光纤所能耦合的离子辐射通量可表述为解析形式的弦积分量。使用卤素气体标准灯对光谱仪进行了波长标定,并确定了仪器响应函数。ERD可提供边界离子温度和旋转速度,是研究C、O、Li、N、He、Ar等离子在可见光波段辐射的有效工具。通过对CIII谱线的分析,得到了边界离子温度和边界旋转速度的初步实验结果,环向ERD初步实验结果表明ERD测量边界杂质离子温度及旋转速度的可行性。     

离子径迹结构对SRAM单粒子翻转截面的影响

本文基于北京HI-13串列加速器的单粒子效应测试终端对0.15 μm工艺的SRAM进行了单粒子效应测试,再次验证了在截面曲线接近饱和区部分,高能离子翻转截面低于低能离子翻转截面的现象。采用Geant4对其进行模拟研究,结果表明,相同LET条件下高能离子可在较远处沉积能量,更易使同一存储单元内相邻的节点共享电荷发生单粒子翻转恢复而减小其单粒子翻转截面,而低能离子进行单粒子效应测试的结果相对保守。     

燃耗对船用压水堆温度系数的影响效应分析

根据船用压水堆临界棒位、固体可燃毒物以及核燃料物理性能随燃耗的变化规律,分析了这些参数变化对反应堆温度系数的影响,得出船用压水堆温度系数随燃耗的变化规律,即在整个燃耗寿期内,船用压水堆具有负的温度系数,但随燃耗的加深温度系数的绝对值将逐渐减小.     

辐照温度对双极线性稳压器的辐射效应影响

为研究辐照温度对线性稳压器的电离辐射效应的影响,选取三个公司生产的同一型号线性稳压器7805在不同温度条件下进行60Co?电离辐射效应试验。结果表明:辐照温度的增加使三款线性稳压器输出电压的辐射损伤增大;使国家半导体公司和安森美半导体公司稳压器的线性调整率及国家半导体公司的输入电流敏感参数的辐射损伤减小。结合双极晶体管的空间辐照效应模型,对双极线性稳压器不同温度条件下的辐射损伤效应进行了分析和讨论,表明辐照温度对线性稳压器的辐射敏感参数的影响主要取决于陷阱电荷。     

低剂量γ线照射和苯复合诱发家兔血淋巴细胞和骨髓细胞遗传效应的研究

报道了低剂量γ线照射复合苯诱发家兔血淋巴细胞和骨髓细胞遗传效应的实验研究。结果表明:苯和γ线都能诱发染色体畸变和SCE频率的升高;畸变类型主要是染色体型无着丝粒断片;血淋巴细胞染色体畸变率要比骨髓细胞的高;随剂量的变化,γ线诱发染色体畸变的升高比诱发SCE的要明显得多,但剂量效应线性相关不明显,相反,苯诱发SCE的升高要比诱发染色体畸变的要明显,且血淋巴细胞无着丝粒畸变率和SCE频率与剂量呈线性相关。染色体畸变效应总的趋势是:高复组>低复组>照射组>高苯组>低苯组>对照组;苯能提高γ线诱发的染色体畸变率,在双+环主要是协同,而在无着丝粒主要是相加。     

SC双波源脉冲微波相互垂直复合辐照对大鼠重要组织器官生物效应的影响

本文研究了S和C波段双波源沿相互垂直方向同时辐照时,脉冲数对大鼠血液、脑、睾丸、心脏和肝脏组织的影响,并与相同电磁暴露水平条件下的单波源电磁暴露生物效应进行了比较。结果表明：当空间场强幅值为44.84kV/m,脉冲数为2、5、20和200时,辐照组大鼠的血常规、血清睾酮、谷丙转氨酶（Alanine aminotransferase,ALT）和谷草转氨酶（Aspartate aminotransferase,AST）含量等指标与Control组及Sham组相比均未发生明显变化（p>0.05）。辐照组大鼠的脑、睾丸、心脏和肝脏组织形态正常,细胞核面积统计结果及睾丸组织的Johnson评分结果与Control及Sham组相比均无明显差异（p>0.05）,没有发现明显的病理损伤。辐照组大鼠4个组织中的促凋亡蛋白Bax的含量均随脉冲数增加呈非线性增加趋势,具有脉冲微波辐照在非热效应下的场效应特征。当脉冲数大于2时,脑和睾丸组织出现了明显的凋亡响应（p?0.05）,而心脏和肝脏组织在脉冲数达到20时才出现明显的凋亡响应（p?0.05）,这主要是因为脑和睾丸的内场场强幅值（分别为11.3...     

电子能损效应对材料辐照缺陷影响的理论模拟研究进展

高能粒子与靶材料相互作用主要通过核能损和电子能损两种方式损失能量。电子阻止效应和电子-声子耦合效应是体现电子能损的两种不同机制。准确模拟高能粒子的辐照损伤过程,亟须解决电子能损效应对粒子辐照损伤的影响这一关键科学问题。本文综述了几种关键结构材料在考虑电子能损效应下辐照损伤行为的最新研究进展,阐述了电子阻止效应、电子-声子耦合效应和电子热导率等对辐照缺陷的影响规律,总结了目前电子能损效应对靶材料辐照损伤的影响规律,归纳了高能粒子辐照靶材料研究中存在的问题,并对后续的研究方向进行了展望。     

Fast estimation of ion temperature from EAST charge exchange recombination spectroscopy using neural network

Ion temperature,as one of the most critical plasma parameters,can be diagnosed by charge exchange recombination spectroscopy(CXRS).Iterative least-squares fitting is conventionally used to analyze CXRS spectra to identify the active charge exchange component,which is the result of local interaction between impurity ions with a neutral beam.Due to the limit of the time consumption of the conventional approach(～100 ms per frame),the Experimental Advanced Superconducting Tokamak CXRS data is now analyzed in-between shots.To explore the feasibility of real-time measurement,neural networks are introduced to perform fast estimation of ion temperature.Based on the same four-layer neural network architecture,two neural networks are trained for two central chords according to the ion temperature data acquired from the conventional method.Using the Tensor Flow framework,the training procedures are performed by an error back-propagation algorithm with the regularization via the weight decay method.Good agreement in the deduced ion temperature is shown for the neural networks and the conventional approach,while the data processing time is reduced by 3 orders of magnitude(～0.1 ms per frame) by using the neural networks.     

Study on plasma cleaning of the large-scalefirst mirror of the charge exchange recombination spectroscopy diagnostic on EAST

In the Experimental Advanced Superconducting Tokamak(EAST),the reflectivity of the charge exchange recombination spectroscopy(CXRS)first mirror(FM)was dramatically dropped down to 20%of the original value after the operation of two EAST experimental campaigns from 2014-2015,leading to degradation of the signal intensity of the CXRS diagnostic to an unacceptably low level.The radio frequency(RF)plasma cleaning of the CXRS FM with a dimension of 303×81×76 mm3 and a small curvature of 0.008 mm-1 was performed to remove deposits to recover the reflectivity.After 168 h cleaning by RF plasma,the maximum specular reflectivity of the FM could reach 92%of the original value at 532 nm,making the cleaned CXRS FM eligible to be reused for the CXRS diagnostic in the 2016 EAST campaign.Dedicated tests of sputtering polished mirror samples were performed to explore the cleaning uniformity and possible damage to the mirror surface.The specular reflectivity did not show obvious dependence on locations along the surface with the same cleaning time.The measured surface roughness gradually increased with sputtering time.The reflectivity remained almost unchanged regardless of different sputtering times and locations,indicating negligible damage to the FM surface even after 100 h sputtering.The recontaminated CXRS FM in the 2016 EAST campaign was firstly cleaned for 81 h,and the least reflectivity recovery for areas with relatively thick deposits was only 40%.After continuing cleaning to 147 h,redeposition of the sputtered residual deposits on the FM surface was observed.In the future for in situ cleaning of the FMs in EAST and ITER,deposits should be removed timely when they are very thin taking into account a very long cleaning time and presumable redeposition of thick and nonuniform deposits.     

Real-time measurement and feedback control of ion temperature profile and toroidal rotation using fast CXRS system in JT-60U

A fast charge exchange recombination spectroscopy (CXRS) system has been developed for the real-time measurement and feedback control of ion temperature (T_i) profile and toroidal rotation velocity (V_t) in JT-60U. In order to control T_i and V_t in real-time, the charge exchange recombination spectroscopy with high time resolution, the real-time processor system, and the real-time control system have been developed. Utilizing this system, real-time control of the T_i gradient between r/a ∼ 0.25-0.5 has been demonstrated with neutral beams at high beta plasmas (normalized beta β_N ∼ 1.6-2.8). The strength of the internal transport barrier is controlled. Moreover, the real-time control of V_t has been demonstrated from counter (anti-parallel to the plasma current, I_p) to co (parallel to the I_p) direction. Then the behavior of edge localized mode (ELM) is changed by controlling the V_t.     

Development of signal analysis method for the motional Stark effect diagnostic on EAST

A pilot single-channel Motional Stark Effect (MSE) diagnostic has been developed on EAST since 2015.The dual photo-elastic modulators (PEM) were employed to encode the polarization angle into a time-varying signal.The pitch angle was related to the ratio of modulation amplitude at the second harmonic frequency.A digital harmonic analyzer (DHA) technique was developed for extracting the second harmonic amplitude.The results were validated with a hardware phase lock-in amplifier,and is also consistent with the software dual phase-locking algorithm.     

Observation of filament-like structures in ELMy H-mode plasma with a VUV imaging system developed on the EAST tokamak

On the EAST tokamak, filament-like structures have been observed in ELMy H-mode discharges with a high-speed vacuum ultraviolet (VUV) imaging system. The topos, chronos and their weight can be obtained simultaneously by performing the so-called singular value decomposition (SVD) analysis of raw VUV imaging data. The fluctuation amplitude is observed to be suppressed and enhanced gradually in the edge localized mode (ELM) crash and pedestal recovery phase in the chronos, respectively, while filament-like structures can only be found in the pedestal recovery phase on the topos. The mode structure, i.e. m/n=36/9 (m and n are the poloidal and toroidal mode number, respectively) with ρ₀=0.95, w₀=0.07 (ρ₀and w₀ denote the mode location and mode width, respectively) is derived by a comparison of the synthetic images and the experimental imaging data.