4. What did he assume concerning the mass of these hypothetical particles?
5. Who observed these particles experimentally?
6. Where did Carl Andersen observe mesons?
7. What instruments did physicists use then for observing primary cosmic ray particles?
8. Why were mesons first called "heavy electrons"?
9. How many kinds of mesons were discovered later?
10. What is the difference between n- and u.-mesons?
11. How many types of я-mesons are there?
12. What two particles does n° break up into before reaching the surface of the earth?
13. What is the lifetime of a neutral pion?
14. What particles does the breakup of л° give rise to?
15. Why does if practically never reach the surface of the earth while many ofthe muons reach the surface of the earth?
16. Why is cloud chamber equipment difficult to be sent up in balloons?
17. What new method has been developed by physicists for detecting tracks of cosmic particles at high altitudes?
18. What fact is the photographic emulsion method based on?
• Match the synonyms from both columns.
II
mean, altitude, to affect, to estimate, usual, to result in, regardless of,
to range, actually, in addition, similar, to give rise to, in spite of, ordinary, to result from
alike, to arise from, height, besides, in fact, average, to evaluate, to influence, to vary
to cause, to result in, to give rise to, to bring about — привести к ... to be caused, to result from, to be due to, to arise from — являться результатом ...
• Translate into Russian paying attention to the words in bold type.
1. The errors may have resulted from lack of accuracy in the measurements.
2. Neutron absorption frequently results in the emission of secondary gamma rays.
3. The disintegration ofthe radiative elements gives rise to three types of radiation.
4. The black spots on the surface might be due to long exposure.
5. The compound nucleus formation will bring about elastic scattering.
6. The mistake has been caused by lack of operator knowledge.
Remember!
определительное существительное (какой?) <— (какой?) «- (что?) сущ. + сущ. + сущ.
При переводе такой группы слов следует прежде всего начинать перевод с последнего существительного (определяемого). Все остальные существительные, стоящие перед ним, его определяют.
gam ma-ray sensitivity — чувствительность по гамма лучам
energy-charge relation - зависимость заряда от энергии
• Translate the following word combinations.
electron rest-mass, phase shift analysis, electron velocity distribution, pulse series generator
• Translate into English using both ... and, either... or, neither ... nor.
1. И теория, и практика показывают, что новый метод лучше.
2. Ни он, ни другие ученые не сумели установить это соотношение.
3. Эту книгу можно найти или в библиотеке, или в читальном зале.
4. Отклонение рентгеновских лучей наблюдалось как в магнитном, так и в электрическом поле.
5. Ни я, ни мой друг не смогли решить это уравнение.
CLASSWORK
READING (1 IB)
• Skim the passage rapidly and explain (he title.
THE MYSTERIOUS NEUTRINO
The early studies of radioactive (3-decay (the emission of an electron by an unstable atomic nucleus) led to the conclusion that there is something wrong with the energy balance involved. While the (x-particles emitted by a given radioactive element always carry a well-defined amount of energy characteristic of that particular clement, (3-particles show a wide energy spread (разброс) ranging from almost zero to rather high energy values. Since the total energy liberation in the transformation of one atomic nucleus into another is expected to be the same for all nuclei of a given kind, it was suspected that there would be another particle coming out ofthe nucleus along with the electron that carries the missing (недостающий) balance of energy. This hypothetical particle, which must be electrically neutral and must have a mass that is much smaller than even the mass of an electron, received the name neutrino which means "little neutral" in Italian.
The absence of electric charge and the extremely small mass allow neutrinos to penetrate thick material layers with the greatest of ease; a thick concrete (бетонная) wall is just as ineffective in stopping a beam of neutrinos as a chicken wire fence (проволочная изгородь) is in stopping a swarm (рой) of mosquitos. The neutrinos that are produced in great quantities near the center of the sun in the process of nuclear energy production pierce its entire body and fly away as if there were nothing there at all. It has been estimated theoretically that in order to stop effectively a beam of neutrinos we would need a shield several light-years thick.
In spite of the almost incredible ability of neutrinos to make their "getaway" (выход) physicists managed in 1955 to stop a few of them, thus finding unquestionable proof of their existence. F. Reines and C. Cowen of the Los Alamos Scientific Laboratory used forthis purpose the collision process between neutrinos and the nuclei of hydrogen atoms (protons) in which the neutrino was expected to produce a positron and to transform the proton into a neutron:
я + neutrino^ n + e+
These two scientists built a giant particle counter that registered neutrinos as well as positrons and placed it near one of the nuclear piles. The nuclear reactions taking place in the operating pile produce a tremendous number of neutrinos that stream out through a heavy shielding which holds back all other nuclear radiations. Although the chance of a neutrino hitting a proton and producing the above-mentioned reaction is only 1 out of 103u, some of these reactions do actually take place, resulting in the simultaneous appearance of a neutron and the accompanying positron. Thus, the uncatchable neutrino was finally caught and joined the company of well-established elementary particles.
• Re-read the passage and give answers to the following questions.
1. What made scientists search for a hypothetical particle neutrino?
2. Why do physicists say of a neutrino that it is next to nothing?
3. What experimental procedure did scientists stage to detect neutrinos?
4. Why docs a heavy shielding of a reactor hold back all other nuclear particles but neutrinos?
• Give a free translation of the following passage.
Интерес к космическим лучам сверхвысоких энергий объединяет представителей двух наук — астрофизики и физики элементарных частиц. Дело втом, что, с одной стороны, источниками этого излучения могут быть такие пока недостаточно познанные астрономические объекты, как пульсары, оболочки сверхновых звезд, черные дыры, активные ядра галактики и квазары, и потому информация, приносимая космическим излучением, очень важна для физики космоса. С другой стороны, это излучение состоит из частиц самых больших из известных нам энергий, в тысячи и миллионы раз превосходящих те, которые достигнуты на созданных человеком ускорителях. Вот почему изучение таких частиц имеет важнейшее значение и для физики высоких энергий. В целом же можно сказать, что исследование космических лучей — это своего рода глубокая разведка (reconnaissance) в «горячих точках» науки.
HOMEWORK
(to be done in writing)
1. Translate into Russian.