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Conversion electron spectroscopy represents an important tool for nuclear structure analysis of medium and heavy nuclei. Two iron-free magnetic electron spectrometers of the orange type have been installed at the Institute for Nuclear Physics of the University of Cologne. The very large transmission of 15% and the very good energy resolution of 1% makes the iron-free orange spectrometer a powerful instrument. By means of fast timing techniques, lifetimes of nuclear excited states can be measured with an accuracy better than 20 ps. For the first time, the energy dependent centroid position of prompt events yielding the time-walk characteristics (the prompt curve) of the orange spectrometer fast timing setup has been measured using prompt secondary δ-electrons generated in a pulsed beam experiment. The prompt curve calibrated as a function of energy allows precise lifetime determination down to a few tens of picoseconds by the use of the centroid shift method. [ABSTRACT FROM AUTHOR]

Abstract: CologneAMS is a new centre for accelerator mass spectrometry (AMS) at the University of Cologne. It has been funded by the German Research Foundation (DFG) to improve the experimental conditions especially for those German scientists that apply the AMS technique for their geologic, environmental, nuclear chemical, and nuclear astrophysical research. The new AMS-device has been built by High Voltage Engineering Europe (HVEE) and has been installed in the existing accelerator area of the Institute of Nuclear Physics. The AMS-facility is designed for the spectrometry of 10Be, 14C, 26Al, 36Cl, 41Ca, 129I in and heavy ions up to 236U and 244Pu. The central part of the AMS-facility is a 6MV Tandetron™ accelerator. Downstream of the high energy mass spectrometer an additional switching magnet is used as a further filter element which supplies also additional ports for future extensions of the detector systems. The current status of CologneAMS and the results of the first test measurements will be presented. [Copyright &y& Elsevier]

The DE cay SPEC troscopy (DESPEC) setup for nuclear structure investigations was developed and commissioned at GSI, Germany in preparation for a full campaign of experiments at the FRS and Super-FRS. In this paper, we report on the first employment of the setup in the hybrid configuration with the AIDA implanter coupled to the FATIMA LaBr 3 (Ce) fast-timing array, and high-purity germanium detectors. Initial results are shown from the first experiments carried out with the setup. An overview of the setup and function is discussed, including technical advancements along the path. [ABSTRACT FROM AUTHOR]

Abstract: Conversion electron spectroscopy constitutes an important tool in nuclear structure physics. A high efficiency iron-free Orange type electron spectrometer with an energy resolution of 1–2% has been installed at a beam line of the Cologne 10MV FN Tandem Van-de-Graaff accelerator for in-beam studies of conversion electrons. In combination with a -ray detector array, high efficiency -coincidences can be performed. The newly developed very fast scintillator detector with an energy resolution of about 4% makes it also possible to use -coincidences for lifetime measurements of nuclear excited states. A second iron-free Orange spectrometer can be connected to perform -coincidences. Because of the higher efficiency and the better energy resolution, the use of the Double Orange Spectrometer for lifetime measurements is more powerful. Lifetimes down to 100ps and even less can be determined with an accuracy of about 10ps. The working principle of the Orange spectrometer and the setup of the Double Orange Spectrometer are described. The performances are illustrated by examples of in-beam experiments with a main focus on high precision lifetime measurements. [Copyright &y& Elsevier]

The components, working principle and characteristics of FATIMA (FAst TIMing Array), a fast-timing detector system for DESPEC at FAIR, are described. The core system includes 36 LaBr 3 (Ce) scintillator detectors, a mounting frame for the DESPEC station and a VME-based fast-timing data acquisition system. The current electronic timing circuit is based on V812 constant fraction discriminators and V1290 time-to-digital converters. Gamma-ray energies are measured using V1751 digitisers. Characteristics of the core FATIMA system including efficiency, energy, and coincidence resolving time, as well as limitations, are discussed on the basis of test measurements performed in the S4 cave at GSI, Germany. The coincidence γ - γ time resolution for the prompt 60Co cascade is determined to be ∼ 320 ps full width at half maximum. The total full energy peak efficiency at 1 MeV for the 36 detector array in the DESPEC setup is 2.9%. The energy-dependent prompt response centroid curve with the current CFD/TDC combination is shown to be smooth; the centroid shift method can be applied for the measurement of half-lives below 200 ps. An overview of applications of the FATIMA detectors as an ancilliary system in combination with other detector arrays during recent years is given. Data on the operation of the detectors in the presence of magnetic fields are presented. [ABSTRACT FROM AUTHOR]