文章作者 100test 发表时间 2009:04:10 01:46:10
来源 100Test.Com百考试题网
提出探测的问题:要找一个方法满足研究中微子的两个前提But how can scientists detect a particle that interacts so infrequently with other matter? Twenty-five years(证明非常难以探测) passed between Pauli’s hypothesis that the neutrino existed and its actual detection: since then virtually all research with neutrinos has been with neutrinos created artificially*9C(人工产生,cosmic是宇宙中来的,两者非常不同) in large particle accelerators and studied under neutrino microscopes. But(转折之后更重要,探测的对象不同,之前是人工产生的粒子,之后是宇宙中来的粒子) a neutrino telescope, capable of detecting cosmic neutrinos, is difficult to construct. 第一个条件No apparatus can detect neutrinos unless it is extremely massive(提出条件:仪器特别巨大), because(原因,可暂时不看) great mass is synonymous with huge numbers of nucleons (neutrons and protons), and the more massive the detector, the greater the probability of one of its nucleon’s reacting with a neutrino. 第二个条件In addition, the apparatus must be sufficiently shielded from the interfering effects of other particles.
问题解决了Fortunately, a group of astrophysicists has proposed a means of detecting cosmic neutrinos by harnessing(重点内容) the mass(满足了上文的条件一) of the ocean. Named DUMAND, for Deep Underwater Muon (muon: n. μ介子) and Neutrino Detector, the project calls for placing an array of light sensors at a depth of five kilometers under the ocean surface. The detecting medium is the seawater itself: when a neutrino interacts with a particle in an atom of seawater, the result*8 is a cascade散发 of electrically charged particles and a flash of light*8D that can be detected by the sensors. The five kilometers of seawater above the sensors will shield(满足了上文的条件二,下文可以不用再读) them from the interfering effects of other high-energy particles raining down through the atmosphere.
中微子的研究对天文学的影响The strongest motivation for the DUMAND project is that it will exploit an important source of information(指的就是中微子) about the universe. The extension of astronomy from visible light to radio waves to x-rays and gamma rays never failed to从来(=always) lead to the discovery of unusual objects such as radio galaxies, quasars, and pulsars. Each of these discoveries came as a surprise. Neutrino astronomy*2*3A will doubtless bring its own share of surprises*2C.
1. Which of the following titles best summarizes the passage as a whole?