Response of a dielectric microcalorimeter operating with a feed-back of detection pulse signa

介电微量热计的响应与检测脉冲信号的反馈操作

基本信息

批准号：
14380237
负责人：
MAEHATA Keisuke
金额：
$ 6.08万
依托单位：
Kyushu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

项目摘要

The microcalorimeter detects a single particle of radiation by means of the temperature rise in the absorber kept at low temperatures below 1 K. A sensitive thermometer is important component in the microcalorimeter. The electric capacitance of 0.99SrTiO_3-0.01SrTa_2O_6 dielectric materials exhibits the temperature dependence and the minimum value below 200 mK. The temperature dependence of the electric capacitance can be utilized for the sensitive thermometer of the microcalorimeter. By applying a constant DC voltage, a change in the electric capacitance alters the electric charge stored in the dielectric capacitor. In the dielectric microcalorimeter, the temperature rise induced by the incident radiation is converted to the electric charge proportional to the change in the electric capacitance of the dielectric material. Because of no current-flow across the dielectric device, the dielectric microcalorimeter has advantage of suppression of the Johnson noise and the Joule heat generat … More ion in the device. The temperature dependence of electric capacitance d(ln C_d)/dT of the material is important parameter for the dielectric thermometer. We fabricated 0.99SrTiO_3-0.01SrTa_2O_6 dielectric samples. The experimental value of d(ln C_d)/dT of the dielectric sample was -2.02 at 100mK. However reproducibility in values of d(ln C_d)/dT was not obtained for prototype thermometers made of 0.99SrTiO3-0.01SrTa2O6 dielectric samples. After several researches, the behavior of the value of d(ln C_d)/dT below 1K was found to be affected by a nonstoichiometry between SrO and TiO_2 in 0.99SrTiO_3-0.01SrTa_2O_6 dielectric materials. We fabricated a prototype dielectric microcalorimeter using 0.99SrTiO_3-0.01SrTa_2O_6 dielectric materials. After cooled down below 100 mK by operating a liquid helium-free compact dilution refrigerator, the dielectric microcalorimeter was irradiated by alpha particles emitted from ^<241>Am source. The dielectric microcalorimeter detected 5.5 MeV alpha particles. By applying the bias voltage of 110 V, the pulse height of the detection signal was 1.6 V at the output of a charge sensitive preamplifier. In this study, we demonstrated potential of excellent detection performance of the dielectric microcalorimeter. Less

微量热仪通过保持在1 K以下低温的吸收体中的温升来检测单个辐射粒子。热敏计是微量热仪中的重要组成部分，0.99SrTiO_3-0.01SrTa_2O_6介电材料的电容显示温度。电容的温度依赖性和最小值低于200 mK，可用于敏感温度计。通过施加恒定的直流电压，电容的变化会改变介电电容器中存储的电荷。在介电微量热计中，入射辐射引起的温升被转换为与变化成比例的电荷。由于介电器件中没有电流流过，因此介电微量热计具有抑制器件中约翰逊噪声和焦耳热产生的优点。材料的电容d(ln C_d)/dT的温度依赖性是介电温度计的重要参数。我们制作了0.99SrTiO_3-0.01SrTa_2O_6介电样品，实验得到介电样品的d(ln C_d)/dT。 100mK 时为 -2.02。但是 d(ln 值的再现性对于由 0.99SrTiO3-0.01SrTa2O6 电介质样品制成的原型温度计，未获得 C_d)/dT 经过多次研究，发现低于 1K 的 d(ln C_d)/dT 值的行为受到 SrO 和 SrO 之间的非化学计量的影响。 0.99SrTiO_3-0.01SrTa_2O_6电介质中的TiO_2我们使用0.99SrTiO_3-0.01SrTa_2O_6介电材料制作了原型介电微量热计，通过操作无液氦紧凑型稀释制冷机冷却到100 mK以下后，介电微量热计受到^<241>Am源发射的α粒子的照射。介电微热量计通过施加偏压检测到 5.5 MeV α 粒子。 110 V，电荷敏感前置放大器输出的检测信号脉冲高度为 1.6 V。在这项研究中，我们展示了介电微量热计的优异检测性能的潜力。