Detection of neutrons in the low-temperature environment using superheated superconducting granules

我们利用高温超导TiN颗粒(SSG)靶进行了低温环境中中子探测的研究。实验得到的结论如下：(1)证实了中子引起的翻转信号的数量随着时间的推移而减少。考虑到TiN颗粒周围的~6Li化合物通过与背景中子的相互作用而减少，解释了这一事实。(2)当中子源靠近靶时，翻转信号平均每3小时发生11次，而没有中子源时，翻转信号平均每3小时发生7次。虽然观测数有波动，但SSG通过平均数的差异成功地探测到了中子。在SSG物理领域工作的里斯本大学的Tom Girard同意我们对实验结果的理解。他们建议我们在2000年6月举行的“粒子探测和亚稳态超导电性”(http://alfl.cii.fc.ul.pt/cryo))上公布我们的结果。(3)为了用充分的统计数据重申我们的理解，我们将进行另一项实验，使用的中子源的放射性比这次使用的强一个数量级。根据这里报告的结果进行简单的外推，在使用和不使用新震源之间的平均翻转次数预计每3小时大约40次。

We have carried out a research of the detection of neutrons in a low-temperature environment using a target consisting of superheated superconducting tin granules (SSG). Conclusions obtained from the experiment are as follows.(1) It was confirmed that the number of flip signals due to neutrons decreased with the day. This fact is explained by considering that the compound of 6Li surrounding tin granules decreases through the interaction with background neutrons.(2) The average number of flip signals was 11 events every 3 hours when a neutron source was placed neaby the target, whereas that of flip signals was 7 events without the neutron source. Though the observed numbers fluctuated, the detection of neutrons was succeeded with SSG through the difference of the average numbers.Both George Waysand of Pris Univ. and Tom Girard of Lisboa Univ., who work in the field of SSG physics, agreed with our understanding on results of the experiment. They recommend us to present our results at "Particle Detection & Metastable Superconductivity" (http://alfl.cii.fc.ul.pt/cryo) to be held in June, 2000.(3) To reconfirm our understanding with full statistics, we will have another experiment using a neutron source with radioactivity stronger by one order of magnitude than that used this time. The difference of average flip numbers between with and without the new source is expected to be about 40 every 3 hours in a simple extrapolation from the results reported here.