Development of the Ultra-lav Backgnund Drerctor for neutrinc and clark matter study

开发用于中性和克拉克物质研究的 Ultra-lav Backgnund Drerctor

• 批准号: 10640269
• 负责人: OGAWA Izumi
• 金额: $ 2.18万
• 依托单位: Osaka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10640269/
• 关键词: Dark Matter; neutrino mass; WIMP; double beta decay; CaF_2結晶; wavelength shifter

We have developed a CaFィイD22ィエD2 scintillation detector system (ELEGANTVI) to search for neutrino-less double beta decay of ィイD148ィエD1Ca and spin coupled dark matter by elastic scattering of ィイD119ィエD1F. The whole system is in operation at the underground laboratory located in Nara (Oto Cosmo Observatory). To improve the sensitivity of the detector system, we must increase the number of target nuclei. As a result, The size of the detector system becomes larger which brings the complexity and large costs. To suppress these, we employ a new design of the detector system which consists of CaFィイD22ィエD2 (pure) crystals surrounded by a liquid scintillator as an active 4π-shield.We constructed a test bench system to study the characteristics of this system for future larger detector. One or more CaFィイD22ィエD2 (pure) crystal (s) surrounded by a liquid scintillator are viewed by 4 (5")PMTs. The best value of the concentration of a scintillating solute was obtained by measuring the light yield with varying the concentration. By measuring the decay time of pulses, we can discriminate the signal from the CaFィイD22ィエD2 (pure) scintillator and from the liquid scintillator.We are now studying the best method to discriminate signal from noise by using test bench system.

我们研制了CAFィイD22ィエD2闪烁探测器系统(ELEGANTVI)，用ィイD119ィエD1F的弹性散射研究ィイD148ィエD1Ca和自旋耦合暗物质的无中微子双β衰变。整个系统在位于奈良(Oto Cosmo天文台)的地下实验室运行。为了提高探测器系统的灵敏度，我们必须增加靶核的数量。因此，探测器系统的体积变得越来越大，这带来了复杂性和较大的成本。为了抑制这些问题，我们采用了一种新的探测器系统设计，它由CaFィイD22ィエD2(纯)晶体组成，周围环绕着液体闪烁体作为有源4π屏蔽，我们构建了一个测试平台系统来研究该系统的特性，以用于未来更大的探测器。用4(5“)PMT观察了一个或多个被液体闪烁体包围的CaFィイD22ィエD2(纯)晶体(S)。通过测量不同浓度的光产额，得到了闪烁溶质浓度的最佳值。通过测量脉冲的衰减时间，我们可以区分来自CAFィイD22ィエD2(纯)闪烁体和来自液体闪烁体的信号。我们正在利用实验台系统研究区分信号和噪声的最佳方法。

项目成果

Ogawa, I., et al.: "Dark matter scarch and measurement of double betadecay by ELEGANT VI"RCNP annual report, Osaka University. 35-36 (1999)

Okawa, I. 等人：“ELEGANT VI 的暗物质消耗和双β衰变测量”RCNP 年度报告，大阪大学。

Y. Ishikawa, et al.: "Transmittance of optical glues for CaF_2 Scintillator"OULNS annal report, Osaka University. 13-15 (1999)

Y. Ishikawa 等人：“CaF_2 闪烁体光学胶的透射率”OULNS 年鉴报告，大阪大学。

Ogawa, I, et al.: "Dark matter secarch and measuremeat of double beta decay by ELEGANT VI"RCNP annual report, Osalca Univ.. 35-36 (1999)

Okawa, I, et al.：“通过 ELEGANT VI 进行暗物质搜索和双 β 衰变测量”RCNP 年度报告，Osalca Univ.. 35-36 (1999)

I. Ogawa, et al.: "Dark matter scarch with CaF_2 Santillator at Osaka"Proc. Of the XVth Particles and Nuclei International Coference (PANC'99). (予定). (1999)

I. Okawa 等人：“在大阪使用 CaF_2 Santillator 进行暗物质研究”第 XV 届粒子与核国际会议 (PANC99)（计划）。

M. Itamura, et al.: "Improvement of CaFィイD22ィエD2 Scintillator by Means of Flash Scaler"OVLNS annual report, Osaka Univ.. 16-17 (1999)

M. Itamura 等人：“通过 Flash Scaler 改进 CaF22D2 闪烁体”OVLNS 年度报告，大阪大学 16-17 (1999)