Preliminary results for the design,fabrication,and performance of a backside-illuminated avalanche drift detector

The detection of low-level light is a key technology in various experimental scientific studies. As a photon detector, the silicon photomultiplier （SiPM） has gradually become an alternative to the photomultiplier tube （PMT） in many applications in high-energy physics, astroparticle physics, and medical imaging because of its high photon detection efficiency （PDE）, good resolution for single-photon detection, insensitivity to magnetic field, low operating voltage, compactness, and low cost. However, primarily because of the geometric fill factor, the PDE of most SiPMs is not very high; in particular, for those SiPMs with a high density of micro cells, the effective area is small, and the bandwidth of the light response is narrow. As a building block of the SiPM, the concept of the backside-illuminated avalanche drift detector （ADD） was first proposed by the Max Planck Institute of Germany eight years ago; the ADD is promising to have high PDE over the full energy range of optical photons, even ultraviolet light and X-ray light, and because the avalanche multiplication region is very small, the ADD is beneficial for the fabrication of large-area SiPMs. However, because of difficulties in design and fabrication, no significant progress had been made, and the concept had not yet been verified. In this paper, preliminary results in the design, fabrication, and performance of a backside-illuminated ADD are reported; the difficulties in and limitations to the backside-illuminated ADD are analyzed.     

L-赖氨酸双酶电极的研制及应用

用交联法将赖氨酸脱羧酶与碳酸酐酶共同固定于CO_2电极透气膜上,制成L-赖氨酸双酶电极,讨论了该双酶电极的响应特性。用双酶电极测定了金针菇和强化赖氨酸食品中赖氨酸含量,与氨基酸自动分析仪所得结果一致。     

高温高应变率下G550冷弯钢的动态力学行为

为研究G550冷弯钢在高温和高应变率下的动态力学性能,采用高温同步控制霍普金森拉杆装置,开展了不同温度下的高应变率拉伸试验,并在高速液压拉伸试验机上进行了室温下的中应变率拉伸试验。通过获得的应力-应变曲线,得到了材料的本构模型,结合微观形貌分析,探究了温度和应变率对流变应力的影响。结果表明：G550冷弯钢具有明显的应变率强化和温度软化效应。在特定的高应变率范围内(1 000～1 500 s^-1),温度对流变应力的影响大于应变率。基于温度软化系数随温度变化的特征,提出了G550冷弯钢的修正Johnson-Cook本构模型。该模型可以较好地描述G550冷弯钢在高温和高应变率下的动态力学行为,从而为G550冷弯钢在高温、爆炸冲击相关的有限元仿真提供参考。