HADES is a versatile magnetic spectrometer aimed at studying dielectron production in pion, proton and heavy-ion induced collisions. Its main features include a ring imaging gas Cherenkov detector for electron-hadron discrimination, a tracking system consisting of a set of 6 superconducting coils producing a toroidal field and drift chambers and a multiplicity and electron trigger array for additional electron-hadron discrimination and event characterization. A two-stage trigger system enhances events containing electrons. The physics program is focused on the investigation of hadron properties in nuclei and in the hot and dense hadronic matter. The detector system is characterized by an 85 % azimuthal coverage over a polar angle interval from 18• to 85• , a single electron efficiency of 50 % and a vector meson mass resolution of 2.5 %. Identification of pions, kaons and protons is achieved combining time-of-flight and energy loss measurements over a large momentum range. This paper describes the main features and the performance of the detector system.

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A new ionisation chamber for alpha-spectroscopy has been built from radio-pure materials for the purpose of investigating long lived alpha-decays. The measurement makes use of pulse shape analysis to discriminate between signal and background events. The design and performance of the chamber is described in this paper. A background rate of (10.9±0.6) counts per day in the energy region of 1 MeV to 9 MeV was achieved with a run period of 30.8 days. The background is dominantly produced by radon daughters.

See paper for full list of authorsAfter the completion of the experimental program at SIS18 the HADES setup will migrate to FAIR, where it will deliver high-quality data for heavy-ion collisions in an unexplored energy range of up to 8 A GeV. In this contribution, we briefly present the physics case, relevant detector characteristics and discuss the recently completed upgrade of HADES

We have studied the performance of finger-like LSO:Ce (LSO) crystals coupled one by one to pixels of avalanche photodiode detector (APD) arrays during their operation in coincidence at 12 C ion beams of parameters being typical for tumor irradiations. In a first step of these experiments the parameters of the detectors and the signal processing setup have been characterized off-beam, i.e., by means of + radioactive sources ( 22 Na, 68 Ge). Afterwards, the apparatus was installed at the medical beam line of the heavy ion synchrotron (SIS) of the Gesellschaft für Schwerionenforschung (GSI) at Darmstadt, Germany. Here the + activity produced by nuclear fragmentation reactions of 12 C 200.3 AMeV heavy ion beams with polymerized methyl methacrylate phantoms were measured. Furthermore, a 68 Ge source was included into the in-beam experiment, in order to check the stability of the setup and to compare energy and time resolution before, during, and after the phantom irradiations.Additionally, it could be demonstrated by means of high resolution -ray spectroscopy that LSO is not activated by the light projectile fragments escaping the patients downbeam during therapeutic irradiations The experimental results indicate that LSO scintillator is a suitable material for in-beam positron emission tomography (PET) and, furthermore, the LSO/APD array is a feasible detector concept for in-beam monitoring of the dose application by means of PET.