P. Delahaye

The REX-ISOLDE charge breeder as an operational machine

The charge breeding system of radioactive beam experiment at ISOLDE (REX-ISOLDE), consisting of a large Penning trap in combination with an electron-beam ion source (EBIS), is now a mature concept after having delivered radioactive beams for postacceleration to a number of experiments for three years. The system, preparing ions prior to injection into a compact linear accelerator, has shown to be versatile in terms of the ion species and energies that can be delivered. During the experimental periods 2004 and 2005 a significant part of the ISOLDE beam time was dedicated to REX-ISOLDE experiments. Ion masses in the range between A=7 and 153 have been handled with record efficiencies. High-intensity as well as very-short-lived isotope beams were proven to be feasible. Continuous injection into the EBIS has also been successfully tested. Two means of suppressing unwanted beam contaminations were tested and are now in use. In addition, the experience gained from the trap-EBIS concept from a machine operational point of view will be discussed and the limitations described.

Mass spectrometry of atomic ions produced by in-trap decay of short-lived nuclides

The triple-trap mass spectrometer ISOLTRAP at ISOLDE/CERN has demonstrated the feasibility of mass spectrometry of in-trap-decay product ions. This novel technique gives access to radionuclides, which are not produced directly at ISOL-type radioactive ion beam facilities. As a proof of principle, the in-trap decay of 37K+ has been investigated in a Penning trap filled with helium buffer gas. The half-life of the mother nuclide was confirmed and the recoiling 37Ar+ daughter ion was contained within the trap. The ions of either the mother or the daughter nuclide were transferred to a precision Penning trap, where their mass was determined.

Recent results with the Phoenix booster at ISOLDE

At ISOLDE, CERN the development of charge breeding techniques is one of the key points for numerous future experiments. We report in this article on the latest online tests of the Daresbury Phoenix booster at ISOLDE. The performances of the continuous mode were investigated for different injected stable beams. Preliminary results were obtained with the afterglow pulsing method and two injected noble gas isotopes. These latter tests are of particular interest for the postacceleration of ISOL-type beams.

The WITCH experiment: Acquiring the first recoil ion spectrum

Abstract The standard model of the electroweak interaction describes β-decay in the well-known V–A form. Nevertheless, the most general Hamiltonian of a β-decay includes also other possible interaction types, e.g. scalar (S) and tensor (T) contributions, which are not fully ruled out yet experimentally. The WITCH experiment aims to study a possible admixture of these exotic interaction types in nuclear β-decay by a precise measurement of the shape of the recoil ion energy spectrum. The experimental set-up couples a double Penning trap system and a retardation spectrometer. The set-up is installed in ISOLDE/CERN and was recently shown to be fully operational. The current status of the experiment is presented together with the data acquired during the 2006 campaign, showing the first recoil ion energy spectrum obtained. The data taking procedure and corresponding data acquisition system are described in more detail. Several further technical improvements are briefly reviewed.

Linear radio frequency quadrupole for the cooling and bunching of radioactive ion beams

A linear radio frequency quadrupole has been built for the transport, cooling, and bunching of radioactive ions extracted from an ECR source. The device uses the buffer gas cooling technique and was designed such as to extend the technique for the cooling of very light ions using H2 as buffer gas. We describe here the technical specifications of the device and present results of the first tests concerning the cooling and bunching of stable ions.

First detection and energy measurement of recoil ions following beta decay in a Penning trap with the WITCH experiment

Abstract.The WITCH experiment (Weak Interaction Trap for CHarged particles) will search for exotic interactions by investigating the

Spectroscopic Quadrupole Moments in {96,98}Sr: Evidence for Shape Coexistence in Neutron-Rich Strontium Isotopes at N=60.

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ISOLTRAP mass measurements of exotic nuclides at δm/m=10−8

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Transport and cooling of singly charged noble gas ion beams

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Electron shakeoff following the Β+ decay of trapped 35Ar+ ions

angular correlation via the measurement of the recoil energy spectrum after