Radiation hardness characterization of low gain avalanche detector prototypes for the high granularity timing detector

The high granularity timing detector (HGTD) is a crucial component of the ATLAS phase II upgrade to cope with the extremely high pile-up (the average number of interactions per bunch crossing can be as high as 200). With the precise timing information (σ_t～30 ps) of the tracks, the track-to-vertex association can be performed in the “4-D” space. The Low Gain Avalanche Detector (LGAD) technology is chosen for the sensors, which can provide the required timing resolution and good signal-to-noise ratio. Hamamatsu Photonics K.K. (HPK) has produced the LGAD with thicknesses of 35 μm and 50 μm. The University of Science and Technology of China(USTC) has also developed and produced 50 μm LGADs prototypes with the Institute of Microelectronics (IME) of Chinese Academy of Sciences. To evaluate the irradiation hardness, the sensors are irradiated with the neutron at the JSI reactor facility and tested at USTC. The irradiation effects on both the gain layer and the bulk are characterized by I-V and C-V measurements at room temperature (20 ℃) or ?30 ℃. The breakdown voltages and depletion voltages are extracted and presented as a function of the fluences. The final fitting of the acceptor removal model yielded the c-factor of 3.06×10?16 cm?2, 3.89×10?16 cm?2 and 4.12×10?16 cm?2 for the HPK-1.2, HPK-3.2 and USTC-1.1-W8, respectively, showing that the HPK-1.2 sensors have the most irradiation resistant gain layer. A novel analysis method is used to further exploit the data to get the relationship between the c-factor and initial doping density.     

Preparation and kinetic analysis of Li4SiO4 sorbents with different silicon sources for high temperature CO2 capture

Using diatomite and analytical pure SiO2 as silicon sources,Li4SiO4 sorbents for high temperature CO2 capture were prepared through solid-state reaction method.Phase composition was analyzed by X-ray diffraction,and the CO2 absorption capacity and absorptoin-desorption performance were studied by the simultaneous thermal thermogravimetric analyzer(TG-DSC).The results showed that silicon source had an important influence on CO2 absorption properties.The kinetic parameters for the chemisorption and diffusion processes were obtained by the isothermal study for different silicon sources.The results showed that the activation energies for these two processes were estimated to be 105.427 and 35.928 kJ/mol for the sample with analytical pure SiO2(AS).While for the sample with diatomite(DS),the activation energies for these two processes were estimated to be 78.500 and 20.439 kJ/mol,respectively.     

等温淬火高硅铸钢的显微组织和机械性能

为开发一种新型高硅耐磨铸钢 ,采用扫描电子显微镜研究了不同等温温度下高硅铸钢的显微组织 ,对不同等温温度下高硅铸钢的抗拉强度、冲击韧性和硬度进行了系统研究。结果表明 ,高硅铸钢经等温淬火热处理后 ,在较大的温度范围 (2 4 0～ 4 0 0℃ )内都可以得到单一的由贝氏体铁素体和富碳的残余奥氏体交替排列的奥贝双相组织 (Ausferrite) ,组织中没有碳化物析出。在 2 80～ 3 60℃范围内等温 ,可以获得强度、韧性、硬度配合良好的双相组织。高硅铸钢具有优异的综合机械性能 ,同时具有良好的冷作硬化能力     

异步轧制取向硅钢织构的模拟研究

本文系统地阐述了异步轧制剪切变形条件下板材冷轧织构的模拟计算理论；采用矢量法根据实测的ＯＤＦ构造板材的原始组织、在假设临界滑移系开动几率均等的条件下，运用Ｔａｙｌｏｒ模型对取向硅钢的亚表层和中心层的冷轧织构进行电算模拟；在此基础上，对剪切变形条件一些轧制因素的影响进行了讨论。     

不同侧链聚肽热致液晶的合成及相变行为

分别合成了两种侧链不同的聚肽热致液晶,PDLG和AzoPDLG.两者的主链均为刚直棒状的介晶基元,但PDLG的侧链为柔软的长烷基链,AzoPDLG的侧链则含有刚性的偶氮苯介晶基元和长链的间隔基.利用1H NMR、示差扫描量热分析和偏光显微镜对这些化合物的性质进行了分析与表征,并探讨了不同化学结构的侧链对热致液晶相变行为...     

12—硅钼酸降解产物SiMo11铵盐的合成

在对SiMo_(12)杂多酸降解过程的研究中,首次从H_4SiMo_(12)O_(40)直接降解合成出其降解产物(NH_4)_8[SiMo_(11)O_(39)]·14H_2O。经组成分析,确认其为SiMo_(11)铵盐。利用紫外光谱分析、红外光谱分析、x射线粉末衍射、电位滴定、tga—dta热分析、薄板层析等现代分析手段对合成产物的性质进行了研究。     

硅单晶中的氢催化氧沉淀

红外光谱法研究了硅单晶中的氢催化氧沉淀。     

闪光对焊机可控硅无触点交流自动调压控制系统

本文讨论了LM—150型闪光对焊机的自控系统。通过试验得到了预期的效果。文中给出了设计思想,操作原理和电路分析。     

多孔硅形成过程及孔隙率的计算机模拟

为了用计算机模拟电化学方法制备多孔硅的过程，基于Monte Carlo和扩散限制模型（DLA）建立一种新模型，引入耗尽区范围、腐蚀半径和腐蚀几率等参数，用Matlab来实现．模拟得到了电流密度、HF酸浓度、腐蚀时间以及硅片掺杂浓度等实验条件对多孔硅孔隙率的影响趋势，与实验结果一致，模拟出的孔隙率值也与实验值接近．因此所建立的模型可以用来模拟电化学法制备多孔硅的过程．     

结晶型二聚硅酸钠的制备

研究了合成结晶型层状二聚硅酸钠的方法。由于使用了助熔剂,使反应温度降低了200～500℃ ,从而降低了能耗。由X-Ray粉末衍射法的结果可知,合成出的产品中以所期待的δ型及其变形体β型为主,另外还有少量的α-Ⅲ型和偏硅酸钠。产品结合钙、镁离子的能力A ,B分别为:89.2～ 110.5 mg/g ,95.0～108.8mg/g。