ISOLDE available

Orsay and Mainz groups constitute a main effort in this direction. Certainly, these experiments profit from the excellent performance of the ISOLDE mass-separator and from the wide range of elements available in high production yields [RAV79, RAV84]. 

Most data on ground state properties of nuclei far from stability have been obtained at the on-line mass separator ISOLDE at CERN, where the isotopes of over 60 elements are available with high yields (up to 10 atoms per sec and mass number) and half lives down to 10 sec. [CER85]. Fig. 1 shows the chart of nuclei and indicates those regions where optical spectroscopy has been performed in long isotopic chains. Similar systematics of mass measurements have been restricted until now to the isotopes of the alkaline elements [AUD84]. 

CER85] "ISOLDE USERS GUIDE, ed. by H.-J. Kluge, CERN (1985) available from ISOLDE, CERN. 

ZIN84] Contributions to the Workshop on the ISOLDE programme "On-line in 1985 and Beyond", Zinal 1984 available from ISOLDE/CERN. 

The rest of the apparatus is the same as when operated at the Proton Synchrotron. First tested on cesium [ HUB 78 ], [ THI 81 ] the apparatus was used to uncover the resonance lines of francium for which no optical transition had ever been observed. The CERN on line mass separator, Isolde, makes available a source of more than 10 atoms/sec of chemically and isotopically pure 213 Fr isotope. Such an amount is more than needed for a laser atomic beam spectroscopy. The first step is obviously to locate the resonance line at low resolution, using a broad band laser excitation. In a second step, once the line is located, a high resolution study is undertaken, [ LIB 80] and [ BEN 84]. The observed signal is displayed (fig 3a) at low resolution and(3 b)at high resolution. 

Various scenarios for the future were investigated, including a move to SIN where very much higher proton intensities would have been available, but the proposal finally accepted in December 1983 was to build a second separator (IS3) at the SC and to run the accelerator primarily for Isolde for 4000 hours per year. A cut-away view of how the complete facility will look is shown in Fig. 1. 

Ion sources are also an area where it is planed to make improvements, once the new separator is working and manpower is liberated. New ideas for on-line sources include the laser source (which will probably not make new elements available to Isolde but will certainly improve the selectivity), and ECR sources (where the problem will be to adapt existing ECR technology to the high-temperature, high radiation environment of the Isolde separator). 

ISOLDE at CERN (SC), make it feasible to consider using such secondary ions as projectiles for nuclear reactions. A pressing need for reaction rate data involving radioactive species exists in nuclear astrophysics. This requires having available projectiles (A < 60) in the energy range from about 200 keV/amu to 1.5 MeV/amu. It has been proposed to install an ISOL device at the TRIUMF facility to utilize the available intermediate energy (200-500 MeV), intense (<100 yA) proton beam as the primary production source. The mass analyzed, radioactive beam (RB),... 

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