WIMP tracking with cryogenic nuclear emulsion
WIMP tracking with cryogenic nuclear emulsion
复制标题
使用低温核乳剂追踪 WIMP
DOI：
10.1016/j.nima.2016.06.052
复制
发表时间：
2016
期刊：
影响因子：
--
通讯作者：
M. Kimura et al.
中科院分区：
文献类型：
--
作者：
Goto;K.;Watanabe;M.;Imamura;F.;M. Kimura et al.
定向暗物质搜索实验使我们能够揭示弱相互作用大质量粒子的存在。用于定向测量的有前途的探测器是由具有20 nm或40 nm尺寸的细颗粒银晶体组成的细颗粒核乳剂。实验成功的一个关键任务是消除来自核乳胶中14 C衰变的阻止β射线的电子的背景径迹。为了开始10 kg的实验，需要至少10− 10的电子排斥功率。提出了一种利用核乳胶中声子效应抑制电子背景的低温方法。为了证明原理，我们一直在研究细颗粒核乳胶的灵敏度作为温度的函数，通过暴露于γ射线和离子束与离子注入系统在77-300 K的范围内。γ射线暴露的结果表明，在77 K下，电子抑制能力估计优于3× 10− 9。离子辐照实验结果表明，细颗粒核乳胶对轻、重离子都很敏感，且离子径迹角度可以测量。
Directional dark matter search experiments enable us to reveal the presence of Weakly Interacting Massive Particles. A promising detector for a directional measurement is a fine-grained nuclear emulsion consisting of fine crystals of silver bromide with 20 nm or 40 nm size. A critical task for the success of the experiment is to remove background tracks of electrons coming from stopping beta rays of 14 C decays in the nuclear emulsion. An electron rejection power of at least 10− 10 is needed in order to start a 10 kg experiment. We present a novel cryogenic approach to reject the electron background that makes use of the phonon effect in nuclear emulsion. For the proof of principle, we have been investigating the sensitivity of fine-grained nuclear emulsions as a function of temperature by exposing to gamma rays and ion beams with an ion implant system in the range of 77–300 K. Results of gamma ray exposure indicate that the electron rejection power is estimated to be better than 3× 10− 9 at 77 K. Results of ion exposure imply that fine-grained nuclear emulsion is sensitive to ions which are light and heavy and ion tracks' angle can be measured.