Superconducting neutron detector by using MgB_2

膜结构的MgB_2薄膜的热响应可以用来探测各种辐射。采用溅射技术制备了高质量的MgB_2薄膜。该探测器由0.5μm厚的SiN薄膜上的一条MgB_2薄膜曲折线组成。探测器放置在4K冰箱中，工作温度控制在T_c以下，20ps脉冲激光直接照射MGB_2器件，光纤端部固定在器件前面。采用掺铒光纤放大器(EDFA)和GP-IB衰减器控制激光器功率，利用数字示波器通过低噪声放大器观察输出电压。观察到了由热响应产生的输出信号。对输出信号进行了系统的研究，考虑了器件设计、直流偏置条件、偏置温度和输入激光功率等因素的影响。基于含时的Ginzburg-Landau方程、热力学和电动力学，通过大量的计算机模拟研究了非平衡态热力学。在实际设备的实际条件下，使用地球模拟器(ES)进行了大规模的计算。我们证明了该装置的一个吸引人的应用是通过使用局域能量释放为2.3MeV的^&lt；10&gt；B(n，α)^7Li核反应来作为一种新型的中子探测器。

The thermal response of a membrane-structured MgB_2 film can be used to detect various sorts of radiations. High-quality MgB_2 films were prepared by a sputtering technique. The MgB_2 radiation detector consisted of an MgB_2 thin-film meander line on a 0.5-μm-thick SiN membrane. The detector devices were placed in a 4K refrigerator, and the operating temperature was controlled at a certain temperature below T_c. Light from a 20-ps pulsed laser directly irradiated the MgB_2 device ; the end of the optical fiber was fixed in front of the device. An erbium-doped fiber amplifier (EDFA) and a GP-IB attenuator were used to control the laser power, and the output voltage was observed through a low-noise amplifier by using a digital oscilloscope. The output signals caused by thermal response were clearly observed. Systematic studies of the output signals were conducted, and effects of device design, dc bias conditions, bias temperature, and input laser power were considered. We report the out-of-equilibrium thermodynamics, which was investigated by means of extensive computer simulations based on the time-dependent Ginzburg-Landau equations, thermodynamics, and electrodynamics. Large-scale calculations were carried out under the realistic conditions of actual devices by using an Earth Simulator (ES). We demonstrated that one attractive application is to use the device as a novel neutron detector by employing the ^<10>B(n,α)^7Li nuclear reaction with a local energy release of 2.3 MeV.