P. Jacquinot

THE LUMINOSITY OF SPECTROMETERS WITH PRISMS, GRATINGS, OR FABRY-PEROT ETALONS

Formulas have been established which express the flux given by a spectrometer as a function of the effective resolving power and of the dimension of the dispersive system (area of the base of the prism, or area of the grating, or area of the plates of the etalon). It is thus possible to compare the luminosities of the three types of instruments with, in each case, equal resolving power and equal dimension. This comparison reveals a great superiority of the grating over the prism for all regions of wavelengths, and a great superiority of the etalon over the grating. In the case of the etalon, the overlapping may be overcome by the use of several etalons in series.

Hyperfine structure and isotope shift of the D2 line of 118–145Cs and some of their isomers

Abstract High-resolution laser spectroscopy has been performed on 118–145 Cs and 119m, 121m, 122m, 130m, 134m, 135m, 136m, 138m, Cs.The Cs nuclei have been produced either by spallation of La or by fission of U by the 600 MeV proton beam, from the SC at CERN. The hyperfine structures, spins, and isotope shifts have been measured. The charge radii changes deduced from the isotope shifts exhibit shell effects at N = 82, isomeric staggering for N = 64,66,67 and a strong odd-even staggering for all isotopes with N

Atomic Rydberg States

Publisher Summary This chapter is devoted to the production and detection of Rydberg states; every experiment starts and ends with these processes. The main results of spectroscopic studies are analyzed and a strong emphasis is placed on the effects of external fields as this is probably the domain where the most interesting and sometimes surprising results have been obtained. The radiative properties in addition to lifetime measurements, recent experiments on superradiance, and maser effects in Rydberg states are analyzed. During the last few years, considerable and often unexpected advances have been made in the understanding of the properties of Rydberg atoms. In the same way as liquid crystals in the physics of condensed matter, the study of Rydberg atoms is a beautiful example of a very old subject which had been considered for many years to be fully completed but has been completely revived in a very short time. Various applications concerning, for example, laser isotope separation, microwave detectors, or infrared lasers have been suggested in the chapter.

Hyperfine Spectroscopy of Radioactive Alkali Isotopes

Systematic experimental studies of long series of radioactive isotopes of the same element are now becoming a rapidly developing area. The results obtained in the case of Hg isotopes for instance [1], give a good idea of the attractiveness of such a type of investigation. Moreover, similar studies of radioactive Na isotopes of mass number 21 to 31 have already been performed using high resolution laser spectroscopy [2], and have shown for the first time for such a light element, an appreciable volume shift contribution to the total isotope shift. Obviously, hyperfine results, as well as nuclear spin determinations and precise isotope shift measurements give an ensemble of data that seem to be of crucial importance to a better understanding of nuclear properties and suggest new refinements in theoretical models. The further the isotopes are from magic numbers, the larger the nuclear deformations are expected to be. One has therefore to deal with essentially short-lived species, which requires one to work on-line behind the accelerators where they are produced. In the previously mentioned case of Na atoms for instance, the nuclei were obtained by fission reactions of uranium targets bombarded by 20 GeV protons delivered by the PS synchrotron of C.E.R.N..