标题： ANAIS-25的初步结果 显示英文标题

标题： Preliminary results of ANAIS-25

摘要： ANAIS（用NaI(Tl)闪烁晶体探测年调制）实验旨在利用相同的靶材和探测技术，在卡夫兰克地下实验室确认DAMA/LIBRA的信号。 250公斤超纯NaI(Tl)晶体将作为靶材使用，分成20个模块，每个模块连接两个光电倍增管。 由Alpha Spectra用钾含量低于我们分析技术检测限的粉末生长出的两块各重12.5公斤的NaI(Tl)晶体组成了ANAIS-25装置。 背景贡献正在仔细研究中，并且初步结果已经呈现：通过PSA区分相应的α事件，量化了块状材料中的天然钾含量以及铀和钍放射性链的存在，由于快速调试，宇宙射线诱发的活化同位素的贡献被明确识别并且在数据采集的最初几个月内观察到其衰变。 按照与ANAIS-0和先前原型所确立的程序，块状NaI(Tl)闪烁事件的选择和光收集效率也在ANAIS-25中进行了研究。 显示英文摘要

摘要： The ANAIS (Annual Modulation with NaI(Tl) Scintillators) experiment aims at the confirmation of the DAMA/LIBRA signal using the same target and technique at the Canfranc Underground Laboratory. 250 kg of ultrapure NaI(Tl) crystals will be used as a target, divided into 20 modules, each coupled to two photomultipliers. Two NaI(Tl) crystals of 12.5 kg each, grown by Alpha Spectra from a powder having a potassium level under the limit of our analytical techniques, form the ANAIS-25 set-up. The background contributions are being carefully studied and preliminary results are presented: their natural potassium content in the bulk has been quantified, as well as the uranium and thorium radioactive chains presence in the bulk through the discrimination of the corresponding alpha events by PSA, and due to the fast commissioning, the contribution from cosmogenic activated isotopes is clearly identified and their decay observed along the first months of data taking. Following the procedures established with ANAIS-0 and previous prototypes, bulk NaI(Tl) scintillation events selection and light collection efficiency have been also studied in ANAIS-25.