[en] A prototype of a new beam profile monitor with tracking and TOF capabilities for degraded beams at HISPEC/DESPEC at FAIR has been built at the Institute of Nuclear Physics at the University of Cologne. The device consists of two detectors in series, each with an active area of 80 x 100mm². The working principle is based on secondary electrons being created by the ions passing through a thin sheet of material. Afterwards they are accelerated and deflected out of the projected ion beam path by an electrostatic top-assembly. The final sub-assembled electron-detector consists of a chevron MCP-stack giving a fast timing signal and a position-sensitive dual delay line. The parameters we investigated using a highly modular test-bed are: the spatial resolution, the timing resolution and the tracking capabilities. The absolute position resolution and the ratio between position dependent resolutions on vertical and horizontal axis have been investigated vs. mesh characteristics, accelerating and deflection potentials, the beam position and its trajectory. Further analysis of the position dependency of the spatial resolution due to the spread of secondary electrons are under investigation. Concerning the TOF resolution we achieved ∼210 ps with a highly divergent alpha beam from a coated ²⁴¹Am source. Simulations showed the intrinsic resolution to be better. First results and conclusions are presented.

[en] In the context of the HISPEC/DESPEC part of NUSTAR at FAIR-GSI we are investigating the development of new tracking detectors to reconstruct the kinematics of the ions after they are decelerated to energies of about 5 MeV/u. The main issue encountered with slowing down relativistic beams is the energy straggling and the spread in space and direction of these beams. Thereby, new generations of beam-characterization detectors are requested to allow not only the precise determination of the position of an incoming ion and its energy loss but also the arrival time (for time of flight purposes-TOF) and if possible to reconstruct the ion track (Beam Tracking Detector), as well. Our solution uses the secondary electrons generated by ions passing through a thin sheet of material (80-120 μg/cm²). Two basic units of large sensitive area (∝80 x 100 mm²) are placed downstream of the beam axis and electrostatic mirrors project the secondary electrons on the position sensitive detectors. The transparency of each component is ∝90%, making the overall transparency of one unit ∝70%. We aim to get an angular resolution of about 1.5-2.5.10^-2 steradian with a sub-ns resolution for the TOF. Even though the S/N ratio per current pulse is very promising, we are facing a very high pulse shot noise at the MCP outputs. The source of these additional electrons is under investigation.

[en] In the context of the future HISPEC/DESPEC facility at the low energy branch of the Super-FRS at FAIR a setup for slowed down beams is planned. With this facility, short lived, fast decaying radionuclides far off the valley of stability will become accessible. In order to open certain reaction channels with a high cross section at lower energies, the fast extracted beams have to be slowed down by a degrader, which will induce a certain amount of spallation products and the primary ions themself will undergo energy and spatial straggling. Thus one needs to know whether one of the desired ions is hitting the target or not. To address this problem, a detector capable of measuring the time of flight and the trajectory of each ion is to be placed between the degrader and the target. This detector has to introduce as less material as possible in the beam. The solution we are investigating uses an emissive foil detector with an active area of 80 x 100 mm² and a timing resolution of ∼210 ps. This prototype has been tested and included in the GSI data acquisition system to tag and track fission products from an open Cf-source. The results and a planned future setup for FAIR are presented.

No abstract available

[en] At the center for accelerator mass spectrometry (CologneAMS) a complex beam detector consisting of a high resolution Beam Profile Monitor (BPM) and a Time of Flight (TOF) spectrometer with tracking capabilities was designed especially for the needs of the Cologne AMS facility. The complex beam detector assembly is designed to match the beam specifications of the 6MV Tandetron AMS setup and its DAQ system, which is presently in the commissioning phase at the IKP of the University of Cologne. The BPM-TOF system will have a reconfigurable structure, namely: either a very fast TOF subsystem with a small active area or a more complex BPM -TOF detector with beam tracking capabilities and with a large active area. The systems aims for background suppression in case of the spectrometry of heavy ions, e.g. U, Cm, Pu, Am etc. and could also be used as an additional filter e.g., for the isobar ³⁶S in case of the spectrometry of ³⁶Cl.

No abstract available

[en] At the PF1B cold neutron beam line at the Institut Laue Langevin the EXILL array consisting of EXOGAM, GASP and LOHENGRIN detectors was used to perform (n,γ) measurements under very high coincidence rates. About ten different reactions were then measured in autumn 2012. In spring 2013 the EXOGAM array was combined with 16 LaBr₃(Ce) scintillators in the FATIMA rate at EXILL campaign for the measurement of lifetimes using the generalised centroid difference method. We report on the properties of both set-ups and present first results on Pt isotopes from both campaigns.

[en] At the center for accelerator mass spectrometry at the University of Cologne (CologneAMS) a complex beam detector consisting of a high resolution Beam Profile Monitor (BPM) and a Time of Flight (TOF) spectrometer with tracking capabilities was developed especially for the needs of the Cologne AMS facility. The complex beam detector assembly is designed to match the beam specifications of the 6MV Tandetron AMS setup and is fully compatible with its DAQ system. The TOF-BPM system was designed in a reconfigurable structure, namely: either a faster TOF subsystem with a smaller active area or a more complex TOF-BPM detector with beam tracking capabilities and with a larger active area of ∝16 sq.cm. The system was put in operation in Nov. 2011 and it was successfully tested with various ion beams of Be, C, Cl etc. The system aims for background suppression in case of the spectrometry of heavy ions, e.g. U, Cm, Am etc. Using additional thin degraders mounted in the first detector head, the system could also be used for tagging isobars, i.e. isobar separations. We report on details of the design and on first experimental results obtained with accelerated beams (timing resolution, spatial resolution and tracking capabilities in conjunction with some auxiliary detectors)

No abstract available

[en] Data on a new microsecond isomer in ⁹⁷Rb are presented. The measurement was conducted at the LOHENGRIN mass separator at the ILL, Grenoble. We were able to deduce the level energy and lifetime of the state. The multipolarity of the transition to the ground state was determined using conversion electron spectroscopy. This information enabled us to assign a spin and parity to the state, based on quasi-particle-rotor model calculations. The nucleus ⁹⁷Rb has neutron number 60, and is thus situated in the shape-phase transition line of the mass 100 nuclei. It is discussed how the new state fits into the region and the Rb-isotopic chain. Furthermore some new results on the decay of the 9/2⁺ microsecond isomer of ⁹⁷Sr are presented and discussed.