Experimental setups

Temporary experimental setups

The setups which come to ISOLDE for shorter periods are usually systems used for detection of specific decay modes of the studied nuclei. Some of them measure the gamma-rays and beta decay and strive to reconstruct the position of excited levels of the nucleus. Others use very fast gamma detectors which can say for how long different excited states live. There are setups which detect neutrons or protons, as well as alpha particles which are emitted in the decay of some nuclei. Also, systems to measure the millisecond to minute lifetime of different isotopes are used. The physics interest of these experiments spans from nuclear structure physics, through nuclear astrophysics, up to fundamental studies and applied science.

Fixed experimental setups

ASPIC

Surfaces and interfaces are of crucial importance for the understanding of properties and processes in matter. Although most characteristics of surfaces differ drastically from the ones in the bulk, rarely more than five atomic layers are of relevance to describe the fundamentals of topics such as heterogeneous catalysis, corrosion or microelectronics. Despites this intense interest there are only very few techniques available to probe local properties with high sensitivity on surfaces and interfaces.

COLLAPS

COLLAPS (COLlinear LAser SPectroscopy) is a small experiment located at the “isotope factory” ISOLDE at CERN. Its aim is the investigation of ground state properties of exotic, short lived nuclei, such as spins, electro-magnetic moments and charge radii. All these observables contribute widely to our understanding of the nuclear force – they give valuable information about the coupling between nucleons, about symmetry of the nuclear wave-functions and thus about the symmetry of the nuclear interaction itself."

CRIS

The CRIS (Collinear Resonant Ionization Spectroscopy) experiment at CERN ISOLDE is joining together the high resolution of collinear laser spectroscopy with the high efficiency and selectivity of resonant ionization. It is used to study the ground-state properties of exotic nuclei, such as spins, nuclear moments and shapes, and to produce beams of high isomeric purity for dedicated decay studies.

ISOLTRAP

Precision mass measurements are performed at the mass spectrometer ISOLTRAP with a relative mass uncertainty routinely reaching to 1*10^-8. The time-of-flight detection technique is employed to determine the frequency of an ion stored in a Penning trap, from which the mass can be extracted. The system has studied nuclides with half-lives below 100ms and production yields of less than 1000 ions per second, supplied by the isotope separator ISOLDE at CERN.

LUCRECIA

Lucrecia is a Total Absorption gamma Spectrometer (TAS) located at the ISOLDE hall. It has been designed to measure feeding in beta decay through the detection of the gamma cascades following the decay. The b-feeding is one of the main ingredients in the calculation of the b-strength function, and is thus an essential element in the  proper estimation of the B(GT) or B(F).

MINIBALL

The high-resolution Miniball germanium detector array has been operational at REX-ISOLDE at CERN for over 10 years. This array consists of 24 six-fold segmented, tapered, encapsulated high-purity germanium crystals and was specially designed for low multiplicity experiments with low-intensity radioactive ion beams (RIB). For work with rare-isotope beams, the multiplicities are low (often only a few states are excited) and the yields of such beams are usually much lower than for conventional experiments, so efficiency is paramount.

NICOLE

The Nicole On-Line Nuclear Orientation facility comprises a large 3He/4He refrigerator with room temperature side access through which an ion beam from ISOLDE can be introduced to impinge upon a suitable metallic foil maintained at temperatures down to below 10 millkelvin. Using ferromagnetic foils, the implanted nuclei experience hyperfine magnetic fields of order 20 – 200 T, sufficient to produce large degrees of nuclear polarization subject to a spin-lattice relaxation time which can vary between hours and milliseconds.

WITCH

The WITCH experiment has been set up for investigation of the weak interaction focussing on the b-n angular correlation coefficient a. This is determined by measuring the recoil energy distribution of daughter nuclei after b decay. A precision experiment with e.g. 35Ar will set new limits for a scalar contribution to weak interaction.

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