a S. Abdel-Samad, a J. Bojowald, d A. Budzanovski, i A. Chatterjee, g J. Ernst, h D. Frekers, a,c P. Hawranek, a,e J. Ilieva, c L. Jarczyk, a K. Kilian, d S. Kliczewski, l D. Kirillov, a,c W. Klimala, f D. Kolev, n M. Kravčíková, e T. Kutsarova, j J. Lieb, a H. Machner, a,c A. Magiera, m G. Martinská, k H. Nann, e L. Pentchev, l N. Piskunov, a D. Protić, a P. von Rossen, i B. J. Roy, l I. Sitnik, d R. Siudak, a,m M. Uličný, c A. Strzałkowski, f R. Tsenov, a,g J. Urbán, b K. Zwoll a Institut für Kernphysik, Forschungszentrum Jülich, Germany, b Zentallabor für Elektronik, Forschungszentrum Jülich, Germany, c Institute of Physics, Jagellonian University, Krakow, Poland, d Institute of Nuclear Physics, Krakow, Poland, e Institute of Nuclear Physics and Nuclear Energy, Sofia, Bulgaria, f Physics Faculty, University of Sofia, Bulgaria, g Institut für Strahlen – und Kernphysik der Universität Bonn, Germany, h Institut für Kernphysik, Universität Münster, Germany, i Nuclear physics Division, BARC, Bombay, India, j Physics department, George Mason University, Fairfax, Virginia, USA, k IUCF, Indiana University, Bloomington, Indiana, USA, l LHE, JINR Dubna, Russia, m P. J. Šafárik University, Košice, Slovakia, n Technical University Košice, Slovakia.

Several processes of meson production in proton-deuteron collisions have been measured simultaneously using a calibrated magnetic spectrograph. Among these processes, the η meson is seen clearly as a sharp missing-mass peak on a slowly varying background in the p + d → He + X reaction. Knowing the kinematics of the other reactions with well determined masses, it is possible to deduce a precise mass for the η meson. The final result, m(η) = 547.311 ± 0.028 (stat) ± 0.032 (syst) MeV/c, Preprint submitted to Elsevier Science 19 November 2013 is significantly lower than that found by the recent NA48 measurement, though it is consistent with values obtained in earlier counter experiments.

Very recently we have shown that CUBE-preamplifiers developed by XGLab s.r.l. can be used for the readout of single elements of thick structured planar HPGe- and Si(Li)-detectors produced by SEMIKON [1]. In this paper we will present the results of a simultaneous multi-element readout of structured detectors using the same preamplifiers for measuring high-energy x-rays (more than 100 keV) with a comparable energy resolution as for the single-element readout. Several high-purity germanium detectors (HPGe-detectors) with different position sensitive structures on one detector contact have been used for the first tests. In addition to that we have modified an existing 16-pixel HPGe-polarimeter from GSI-Darmstadt with the new readout. The detector elements (7 mm × 7 mm each, arranged in a 4 × 4 matrix) are connected to CUBE-preamplifiers used in pulse-reset mode. The technological progress achieved with this detector system resulting in a significant improved energy resolution will contribute a lot to much more precise polarization measurements of x-rays emitted from atom-ion collisions which are part of the physics program of the SPARC collaboration (Stored Particles Atomic Physics Research Collaboration) at GSI and the future FAIR accelerator facility (Facility for Antiproton and Ion Research).

Multi-element germanium detectors for X-ray fluorescence are widely used in synchrotron experiments and in particular in XAFS experiments. This paper presents the construction and characterization of a demonstrator built to investigate the viability of multi-element monolithic germanium detectors equipped with CMOS front-end electronics. Semikon Detector GmbH fabricated a germanium sensor segmented with a pad pattern with pad size 1 x 1 mm(2). 16 channels were instrumented with the CUBE preamplifiers developed at XGLab Srl. The detector was tested with radioactive sources and with the synchrotron X-ray beam of Diamond. The results showed spectra with energy resolution satisfactory for XAFS experiments but with a considerable tail. The low energy tail was proved to be due to charge sharing. In addition the spectra showed the peak stability as a function of counting rate better than 1% for rate up to 838 kcps. The non-linearity of the peak position vs. energy was estimated to be a maximum of 0.13% No evidence of charge loss in the crystal was identified. This work proved that this technology is a viable option to improve the throughput of germanium fluorescence detectors as long as methods to reduce events leading to charge sharing are in place.

Future synchrotron experiments will strongly require detectors suited for high-energy photons ( > 20 keV) which have a good position resolution combined with an excellent energy resolution (far below 1 keV [FWHM] depending on the element size and capacitance). SEMIKON has already built several fine-structured Si(Li)- and HPGe-detectors [1], but up to now they were read-out by conventional preamplifiers placed far away from the position elements. Therefore the achieved energy resolution ( ∼ 1.6 keV [FWHM] @ 60 keV) was not suitable for synchrotron applications. To achieve a better energy resolution CUBE preamplifiers (developed by XGLab s.r.l.) were used for the read-out of the detector elements. The CUBE preamplifier was originally developed to work in combination with detectors which have a very low capacitance (e.g. Silicon Drift Detectors). With such detectors it was already shown that a very good energy resolution can be achieved even at high count rates [2,3]. With this work, we will show that CUBE can have a good performance also with detectors having a higher capacitance. We will present the very first results of measurements which were performed with structured planar HPGe- and Si(Li)-detectors (multi-element detectors) in combination with the CUBE ASICs.

We have constructed a pixelated germanium detector using a technique which has been shown to provide good isolation between adjacent pixels. In this work we present initial tests of the application of a low-noise CMOS ASIC to read out this detector. The detector has 64 pixels, each 0.5mm × 5mm, arranged as a series of strips. It is connected by wire-bonds to two 32-channel ASICs (Application-Specific Integrated Circuit) which provide a complete photon-counting chain for every channel. Since the size of the pixel array is no longer restricted by the difficulties of instrumenting large channel-count conventional electronics, this development will open up the possibility of even larger arrays, similar to those offered by silicon detectors.

The 3α (triple-alpha) process leading to the formation of stable carbon in the Universe is one of the most important nuclear astrophysical processes. The radiative width of the so called Hoyle-state, involving the 7.654 MeV E0 and the 3.215 MeV E2 transitions, is known with 12.5% accuracy. We report on the development of a Si(Li)-detector array for a new magnetic pair spectrometer, which will be used for the measurement of the pair conversion of the E0 and E2 transitions from the Hoyle-state. The results of the final detector tests will be presented.

The General AntiParticle Spectrometer (GAPS) is a novel approach for indirect dark matter searches that exploits cosmic antideuterons. The GAPS detection method involves capturing antiparticles into a target material with the subsequent formation of an excited exotic atom. The exotic atom decays with the emission of atomic X-rays and charged particles from nuclear annihilation, which uniquely identifies the captured antiparticle. We are currently developing the lithium-drifted silicon (Si(Li)) detector for the GAPS flight experiment. In this paper, we describe the diagnostic tests conducted on three prototype Si(Li) detectors and the noise model to characterize each detector. The GAPS prototype flight, preparatory for a long duration balloon flight from Antarctica in 2016–2017, is scheduled for launch from Japan in summer 2012.

The reaction pp -> K^+ + (Lambda p) has been measured at T_p = 1.953 GeV and \Theta = 0 deg with a high missing mass resolution in order to study the Lambda p final state interaction. Narrow S = -1 resonances predicted by bag model calculations are not visible in the missing mass spectrum. Small structures observed in a previous experiment are not confirmed. Upper limits for the production cross section of a narrow resonance are deduced for missing masses between 2058 and 2105 MeV/c^2.

Results of the first measurements on HPGe- and Si(Li)-detectors with an one dimensional fine pitch strip structure are presented. The position-sensitive structures were fabricated on implanted boron contacts by means of photolithography with a subsequent plasma etching. A group of 5 neighbouring strips of both detector types was examinated concerning the reverse current, resistance between a position-element and the neighbourhood and the response to the photons up to 60 keV.

The reaction pp -> K^+ + (Lambda p) has been measured at T_p = 1.953 GeV and \Theta = 0 deg with a high missing mass resolution in order to study the Lambda p final state interaction. Narrow S = -1 resonances predicted by bag model calculations are not visible in the missing mass spectrum. Small structures observed in a previous experiment are not confirmed. Upper limits for the production cross section of a narrow resonance are deduced for missing masses between 2058 and 2105 MeV/c^2.

A large set of high precision cross sections, vector Ax, Ay and tensor Axx, Axy, Ayy analyzing powers for the [Formula: see text] breakup reaction were measured at 130 MeV beam energy with the detection system covering a large part of the phase space. Results are compared with rigorous theoretical calculations employing various models of the three-nucleon system dynamics. The cross section data allowed to establish evidence for three-nucleon force contributions and to confirm predictions of sizable effect of the Coulomb force in the breakup reaction. Analyzing power data are generally quite well described by theoretical predictions even with pure NN interactions. However, in some regions discrepancies has been observed for tensor analyzing powers, only rarely cured by inclusion of the three nucleon force. This indicates incompletness of the present-day treatment of the spin part of three nucleon system dynamics.

The cross section for the reaction $p+{}^{6}\text{Li}\ensuremath{\rightarrow}\ensuremath{\eta}+{}^{7}\text{Be}$ was measured at an excess energy of $11.28$ MeV above threshold by detecting the recoiling $^{7}\mathrm{Be}$ nuclei. A dedicated set of focal plane detectors was built for the magnetic spectrograph Big Karl and was used for identification and four-momentum measurement of $^{7}\mathrm{Be}$. A differential cross section of $\frac{d\ensuremath{\sigma}}{d\ensuremath{\Omega}}=[0.69\ifmmode\pm\else\textpm\fi{}0.20\text{(stat.)}\ifmmode\pm\else\textpm\fi{}0.20\text{(syst.)}] \text{nb/sr}$ for the ground state plus $1/{2}^{\ensuremath{-}}$ was measured. The result is compared to model calculations.

We have measured inclusive data on K+-meson production in pp collisions at COSY Jülich close to the hyperon production threshold and determined the hyperon–nucleon invariant mass spectra. The spectra were decomposed into three parts: Λp, Σ0p and Σ+n. The cross section for the Σ+n channel was found to be much smaller than a previous measurement in that excess energy region. The data together with previous results at higher energies are compatible with a phase space dependence.

The cross section for the reaction p + Li-6 -> eta + Be-7 was measured at an excess energy of 11.28 MeV above threshold by detecting the recoiling Be-7 nuclei. A dedicated set of focal plane detectors was built for the magnetic spectrograph Big Karl and was used for identification and four-momentum measurement of Be-7. A differential cross section of d sigma/d Omega = [0.69 +/- 0.20(stat.) +/- 0.20(syst.)] nb/sr for the ground state plus 1/2(-) was measured. The result is compared to model calculations.

We have studied the reaction p+{sup 27}Al {yields} {sup 3}He+p+{pi}{sup -}+X at recoil-free kinematics. An {eta} meson possibly produced in this reaction would be thus almost at rest in the laboratory system and could therefore be bound with high probability, if nuclear {eta} states exist. The decay of such a state through the N*(1535) resonance would lead to a proton-{pi}{sup -} pair emitted in opposite directions. For these conditions we find some indication of such a bound state. An upper limit of {approx_equal}0.5 nb is found.

The extracted s-wave scattering amplitude from both the polarized and unpolarized d + d → 4 He + η reaction at 2385.5 MeV/c allowed to determine the scattering length which fulfills the requirements for bound η. In the p + 27 Al → 3 He + p + π - + X reaction studied at recoil free kinematics the η meson is produced almost at rest and so it can be bound with enhanced probability. This state proceeds via N*(1535) resonance and the decay products proton and pion emitted into opposite direction are detected in concidence with 3 He produced at zero degree. Under these conditions some hints for bound state can be observed with an upper limit of the cross section of ≈ 0.5 nb.