부산대학교 도서관

We propose a new method of measuring 85Kr background levels by direct counting of impurity atoms. The beta-decay of 85Kr is a significant radioactive background for experiments that use liquified noble gases to search for dark matter and measure the low-energy solar neutrino flux. While there are several proposed methods for reducing Kr levels in these experiments, an independent technique is needed for measuring very low Kr levels. By selectively exciting Kr atoms to a metastable state, capturing them in a magneto-optical trap (MOT), and detecting fluorescence from the trapped atoms, individual Kr atoms can be counted with a high signal-to-noise ratio. This approach offers both higher sensitivity and shorter measurement times than more conventional techniques, with an estimated sensitivity of 3 × 10-14 in only 3 hours of integration. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]