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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

微量热计通过在低于1K的低温下吸收体中的温升来检测单个辐射粒子。灵敏的温度计是微量热计中的重要部件。0.99SrTiO3-0.01SrTa_2O_6介电材料的电容随温度变化，在200mK以下有极小值。利用电容对温度的依赖关系，可以作为微量热计的灵敏温度计。通过施加恒定的直流电压，电容的变化改变了存储在介质电容器中的电荷。在介质微量热计中，入射辐射引起的温升被转换为与介质材料的电容变化成正比的电荷。由于没有电流流过介质器件，介质微量热计具有抑制约翰逊噪声和产生焦耳热…的优点设备中有更多的离子。材料的电容d(Ln C_D)/dt与温度的关系是介质温度计的重要参数。制备了0.99SrTiO3-0.01SrTa_2O_6介电样品。100mK时，d(Ln C_D)/dt的实验值为-2.02。然而，用0.99SrTiO_3-0.01SrTa_2O_6介质样品制成的原型温度计的d(Ln C_D)/dt值不能获得重复性。经过多次研究发现，0.99SrTiO3-0.01SrTa_2O_6介电材料的d(Ln C_D)/dt在1K以下的行为受SrO和TiO_2之间的非化学计量比的影响。利用0.99SrTiO3-0.01SrTa_2O_6介质材料制作了一台介电微量热计样机。在运行无氦紧凑型稀释式制冷机将介电微量热计冷却到100MK以下后，介电微量热计受到来自&lt；241&gt；Am源的α粒子的辐照。介电微量热计探测到5.5 MeV的阿尔法粒子。在110V的偏置电压下，电荷灵敏前置放大器输出的检测信号脉冲高度为1.6V。在这项研究中，我们展示了介电式微量热计良好的检测性能的潜力。较少