Facility For Antiproton And Ion Research Research Articles

Theoretical and experimental evaluation of piezo-optic parameters and photoelastic constant in tetragonal PWO.

The tetragonal PbWO4 (PWO) is one of the most important scintillating crystals, being used both in the Compact Muon Solenoid (CMS) experiment at the European Organization for Nuclear Research (CERN) and in the PANDA project at the Facility for Antiproton and Ion Research (FAIR). Light yield and other relevant scintillation properties depend, among many factors, also on the crystal mechanical quality. Accordingly, a detailed knowledge of crystal piezo-optic properties is a mandatory step toward understanding elasto-optic behavior and performing crystal quality control. In this paper, we evaluate for the first time, to the best of our knowledge, by means of both photoelastic and x-ray measurements, some components of the piezo-optic tensor; moreover, when the crystal is acted upon by a uniaxial stress, we obtain an evaluation for the rotation angle of the optic plane under stress as well as the photoelastic constant. These parameters are necessary to detect the residual stresses within the crystal, if any, and to give an overall quality measure. Such a methodology is in general suitable for any tetragonal crystals.

Influence of the nuclear symmetry energy on the collective flows of charged pions

Based on the isospin-dependent Boltzmann-Uehling-Uhlenbeck (IBUU) transport model, we studied charged pion transverse and elliptic flows in semicentral $^{197}\mathrm{Au}+^{197}\mathrm{Au}$ collisions at 600 MeV/nucleon. It is found that ${\ensuremath{\pi}}^{+}\ensuremath{-}{\ensuremath{\pi}}^{\ensuremath{-}}$ differential transverse flow and the difference of ${\ensuremath{\pi}}^{+}$ and ${\ensuremath{\pi}}^{\ensuremath{-}}$ transverse flows almost show no effects of the symmetry energy. Their corresponding elliptic flows are largely affected by the symmetry energy, especially at high transverse momenta. The isospin-dependent pion elliptic flow at high transverse momenta thus provides a promising way to probe the high-density behavior of the symmetry energy in heavy-ion collisions at the Facility for Antiproton and Ion Research (FAIR) at GSI, Darmstadt or at the Cooling Storage Ring (CSR) at HIRFL, Lanzhou.

Preliminary Design of the FAIR Super FRS Superferric Branched Dipoles

CEA has the responsibility of the design studies for the superferric 1.6 T dipole magnets of the Superconducting FRagment Separator (Super-FRS) which is part of the Facility for Antiproton and Ion Research (FAIR) in Darmstadt, Germany. After completing the study for the 21 superferric Super-FRS standard dipole magnets, CEA is currently analysing conceptual solutions for the three superferric branched dipole magnets. Branched dipole magnets are necessary to allow the separated particles to be directed along each of the three branches of the separator. The branched dipoles will keep most of the features incorporated in the standard dipole magnet design but they will have increased complexity to make them compatible with the vacuum chamber layout at the branches locations (Y-shape). The magnetic design of the yoke will be slightly modified whereas a new cryogenic design is required. This paper presents the design concepts envisioned for the FAIR Super-FRS branched dipole magnets and focuses on preliminary electromagnetic and electro-mechanical simulation results. Concepts for the mechanical and cryogenic designs are also described.

Cosmic matter in the laboratory - the Compressed Baryonic Matter experiment at FAIR

The Compressed Baryonic Matter (CBM) experiment will be one of the major scientific pillars of the future Facility for Antiproton and Ion Research (FAIR) in Darmstadt. The goal of the CBM research program is to explore the QCD phase diagram in the region of high baryon densities using high-energy nucleus-nucleus collisions. This includes the study of the equation-of-state of nuclear matter at neutron star core densities, and the search for the deconfinement and chiral phase transitions. The CBM detector is designed to measure rare diagnostic probes such as hadrons including multi-strange (anti-) hyperons, lepton pairs, and charmed particles with unprecedented precision and statistics. Most of these particles will be studied for the first time in the FAIR energy range. In order to achieve the required precision, the measurements will be performed at very high reaction rates of 1 to 10 MHz. This requires very fast and radiation-hard detectors, a novel data read-out and analysis concept based on free streaming front-end electronics, and a high-performance computing cluster for online event selection. The physics program and the status of the proposed CBM experiment will be discussed.

Radial Flow in a Multiphase Transport Model at FAIR Energies

Azimuthal distributions of radial velocities of charged hadrons produced in nucleus-nucleus (AB) collisions are compared with the corresponding azimuthal distribution of charged hadron multiplicity in the framework of a multiphase transport (AMPT) model at two different collision energies. The mean radial velocity seems to be a good probe for studying radial expansion. While the anisotropic parts of the distributions indicate a kind of collective nature in the radial expansion of the intermediate “fireball,” their isotropic parts characterize a thermal motion. The present investigation is carried out keeping the upcoming Compressed Baryonic Matter (CBM) experiment to be held at the Facility for Antiproton and Ion Research (FAIR) in mind. As far as high-energy heavy-ion interactions are concerned, CBM will supplement the Relativistic Heavy-Ion Collider (RHIC) and Large Hadron Collider (LHC) experiments. In this context our simulation results at high baryochemical potential would be interesting, when scrutinized from the perspective of an almost baryon-free environment achieved at RHIC and LHC.

PANDA Muon System Prototype

The PANDA Experiment will be one of the key experiments at the Facility for Antiproton and Ion Research (FAIR) which is under construction now in the territory of the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany. PANDA is aimed to study hadron spectroscopy and various topics of the weak and strong forces. Muon System is chosen as the most suitable technology for detecting the muons. The Prototype of the PANDA Muon System is installed on the test beam line T9 at the Proton Synchrotron (PS) at CERN. Status of the PANDA Muon System prototype is presented with few preliminary results.

Performance studies of the [formula omitted]ANDA planar GEM-tracking detector in physics simulations

The P¯ANDA experiment will be installed at the future facility for antiproton and ion research (FAIR) in Darmstadt, Germany, to study events from the annihilation of protons and antiprotons. The P¯ANDA detectors can cover a wide physics program about baryon spectroscopy and nucleon structure as well as the study of hadrons and hypernuclear physics including the study of excited hyperon states. One very specific feature of most hyperon ground states is the long decay length of several centimeters in the forward direction. The central tracking detectors of the P¯ANDA setup are not sufficiently optimized for these long decay lengths. Therefore, using a set of the planar GEM-tracking detectors in the forward region of interest can improve the results in the hyperon physics-benchmark channel. The current conceptual designed P¯ANDA GEM-tracking stations contribute the measurement of the particles emitted in the polar angles between about 2 to 22 degrees. For this designed detector performance and acceptance, studies have been performed using one of the important hyperonic decay channel p¯p→Λ¯Λ→p¯pπ+π− in physics simulations. The simulations were carried out using the PandaRoot software packages based on the FairRoot framework.

Recent results with lifetime enhanced microchannel-plate photomultipliers

The favored photon sensors for the DIRC (detection of internally reflected Cherenkov light) detectors at the P̄ANDA (Anti-proton Annihilation at Darmstadt) experiment at FAIR (Facility for anti-proton and ion research) are micro-channel-plate photomultipliers (MCP-PMTs). The main problem until a few years ago was the limited lifetime of the MCP-PMTs caused by a rapid decrease in quantum efficiency (QE) of the photo cathode (PC) with increasing integrated anode charge (IAC). These limitations are overcome by applying an atomic layer deposition (ALD) coating on the MCPs, as recently done by PHOTONIS and Hamamatsu. During the last years’ tests of lifetime enhanced MCP-PMTs were performed and their results were compared. For this, the QE was measured in dependence of the IAC as function of the wavelength and position dependent across the PC. The best performing tubes show a lifetime increase compared to not enhanced devices by a factor >50 with an IAC >13C∕cm2. Additionally, performance results of new 2 inch Hamamatsu tubes and a new high QE PHOTONIS tube are presented.

Planetary physics research programme at the Facility for Antiprotons and Ion Research at Darmstadt

Planetary physics research is an important part of the high energy density (HED) physics programme at the Facility for Antiprotons and Ion Research (FAIR) at Darmstadt. In this paper, we report numerical simulations of a proposed experiment named LAboratory PLAnetary Sciences (LAPLAS). These simulations show that in such experiments, an Fe sample can be imploded to extreme physical conditions that are expected to exist in the interior of the Earth and in the interior of more massive rocky planets named, super‐Earths. The LAPLAS experiments will thus provide very valuable information on the equation‐of‐state (EOS) and transport properties of HED Fe, which will help the scientists to understand the structure and evolution of the planets in our solar system and of the extrasolar system planets.

QCD Matter Physics at FAIR

The Compressed Baryonic Matter (CBM) experiment will be one of the major scientific pillars of the future Facility for Antiproton and Ion Research (FAIR) in Darmstadt. The goal of the CBM research program is to explore the QCD phase diagram in the region of high baryon densities using high-energy nucleus-nucleus collisions. This includes the study of the equation-of-state of nuclear matter at neutron star core densities, and the search for the deconfinement and chiral phase transitions. The CBM detector is designed to measure rare diagnostic probes such as hadrons including multi-strange (anti-) hyperons, lepton pairs, and charmed particles with unprecedented precision and statistics. Most of these particles will be studied for the first time in the FAIR energy range. In order to achieve the required precision, the measurements will be performed at very high reaction rates of 1 to 10 MHz. This requires very fast and radiation-hard detectors, a novel data read-out and analysis concept based on free streaming front-end electronics, and a high-performance computing cluster for online event selection. The status of FAIR and the physics program of the proposed CBM experiment will be discussed.

Net-charge fluctuation in Au+Au collisions at energies available at the Facility for Antiproton and Ion Research using the UrQMD model

We have studied the dynamical fluctuation of net-charge of hadrons produced in Au+Au collisions at energies that in near future will be available at the Facility for Antiproton and Ion Research (FAIR). Data simulated by a microscopic transport model based on ultra-relativistic quantum molecular dynamics are analyzed for the purpose. The centrality and pseudorapidity dependence of the net-charge fluctuation of hadrons are examined. Our simulated results are compared with the results available for nucleus-nucleus collision experiments held at similar energies. The gross features of our simulated results on net-charge fluctuations are found to be consistent with the experiment. At incident beam energy $E_{\rm lab}=10A$ GeV the magnitude of net-charge fluctuation is very large, and in comparison with the rest its centrality dependence appears to be a little unusual. The effect of global charge conservation is expected to be very crucial at FAIR energies. The charge fluctuations measured with varying pesudorapidity window size depend on the collision centrality. The dependence is however exactly opposite in nature to that observed in the Pb+Pb collision at $\sqrt{s_{_{NN}}}=2.76$ TeV.

Studies of the Core Conditions of the Earth and Super-Earths Using Intense Ion Beams at FAIR

Abstract Using detailed numerical simulations, we present the design of an experiment that will generate samples of iron under extreme conditions of density and pressure believed to exist in the interior of the Earth and interior of extrasolar Earth-like planets. In the proposed experiment design, an intense uranium beam is used to implode a multilayered cylindrical target that consists of a thin Fe cylinder enclosed in a thick massive W shell. Such intense uranium beams will be available at the heavy-ion synchrotron, SIS100, at the Facility for Antiprotons and Ion Research (FAIR), at Darmstadt, which is under construction and will become operational in the next few years. It is expected that the beam intensity will increase gradually over a couple of years to its maximum design value. Therefore, in our studies, we have considered a wide range of beam parameters, from the initial beam intensity (“Day One”) to the maximum specified value. It is also worth noting that two different focal spot geometries have been used. In one case, a circular focal spot with a Gaussian transverse intensity distribution is considered, whereas in the other case, an annular focal spot is used. With these two beam geometries, one can access different parts of the Fe phase diagram. For example, heating the sample with a circular focal spot generates a hot liquid state, while an annular focal spot can produce a highly compressed liquid or a highly compressed solid phase depending on the beam intensity.

APPA R&D — BMBF collaborative research at FAIR

SynopsisThe APPA R&D research collaboration at the international Facility for Antiproton and Ion Research (FAIR) in Darmstadt, Germany, is introduced and its activities are briefly summarized pointing out, in particular, the experimental program at the low-energy storage ring CRYRING which will become available for users already in 2018.

The electromagnetic Sigma-to-Lambda hyperon transition form factors at low energies

.Using dispersion theory the low-energy electromagnetic form factors for the transition of a Sigma to a Lambda hyperon are related to the pion vector form factor. The additionally required input, i.e. the two-pion-Sigma-Lambda amplitudes are determined from relativistic next-to-leading-order (NLO) baryon chiral perturbation theory including the baryons from the octet and optionally from the decuplet. Pion rescattering is again taken into account by dispersion theory. It turns out that the inclusion of decuplet baryons is not an option but a necessity to obtain reasonable results. The electric transition form factor remains very small in the whole low-energy region. The magnetic transition form factor depends strongly on one not very well determined low-energy constant of the NLO Lagrangian. One obtains reasonable predictive power if this low-energy constant is determined from a measurement of the magnetic transition radius. Such a measurement can be performed at the future Facility for Antiproton and Ion Research (FAIR).

High brilliance uranium beams for the GSI FAIR

The 40 years old GSI-UNILAC (Universal Linear Accelerator) as well as the heavy ion synchrotron SIS18 will serve as a high current heavy ion injector for the new FAIR (Facility for Antiproton and Ion Research) synchrotron SIS100. In the context of an advanced machine investigation program in combination with the ongoing UNILAC upgrade program, a new uranium beam intensity record (11.5 emA, ${\mathrm{U}}^{29+}$) at very high beam brilliance was achieved recently in a machine experiment campaign. This is an important step paving the way to fulfill the FAIR heavy ion high intensity beam requirements. Results of high current uranium beam measurements applying a newly developed pulsed hydrogen gas stripper (at $1.4\text{ }\text{ }\mathrm{MeV}/\mathrm{u}$) will be presented in detail.

Measurement and optimization of the light collection uniformity in strongly tapered PWO crystals of the PANDA detector

The uniformity of the light collection is a crucial parameter for detectors based on inorganic scintillation crystals to guarantee a response proportional to the deposited energy. Especially in case of tapered crystals, like they are widely used to realize a 4π geometry of electromagnetic calorimeters (EMC) in high energy physics experiments, a strong non-uniformity is introduced by an additional focusing of the scintillation light due to the tapered geometry. The paper will discuss the determination and the reduction of the non-uniformity in strongly tapered lead tungstate crystals as used for the construction of the electromagnetic calorimeter of the PANDA detector at the future Facility for Antiproton and Ion Research (FAIR). Among different concepts for an uniformization a single de-polished lateral side face provided the optimum result with a remaining non-uniformity below 5% in good agreement with similar studies for the CMS ECAL at LHC. The impact on the achievable energy resolution in the energy regime of photons below 800MeV is discussed in detail in comparison to GEANT4 simulations. The comparison of the response of two arrays with polished and de-polished crystals, respectively, shows in the latter case a significant improvement of the constant term of the parametrization of the energy resolution down to 0.5% accompanied by only very slight increase of the statistical term.

Hot Quarks 2016: Workshop for young scientists on the physics of ultrarelativistic nucleus-nucleus collisions

The 7th edition of the Workshop for Young Scientists on the Physics of Ultra-relativistic Nucleus-Nucleus Collisions (Hot Quarks 2016) was held on South Padre Island, Texas, United States from September 12-17, 2016. Following the traditions of the conference, the meeting gathered almost 70 participants in the first years of their scientific careers. The present issue contains the proceedings of this workshop.As in the past, the Hot Quarks workshop offered a unique atmosphere for lively discussions and interpretation of the current measurements from high-energy nuclear collisions. Dedicated time at the end of each session for questions, including anonymous questions from the “box”, are crucial for this workshop. Recent results and upgrades at CERN's Large Hadron Collider (LHC) and Brookhaven's Relativistic Heavy Ion Collider (RHIC) were presented. Recent theoretical developments were also extensively discussed as well as the perspectives for future facilities such as the Facility for Antiproton and Ion Research (FAIR) at Darmstadt and the Electron-Ion Collider at Brookhaven. The conference's goal to provide a platform for young researchers to learn and foster their interactions was successfully met.We wish to thank the sponsors of the Hot Quarks 2016 Conference, who supported the authors of this volume: European Laboratory for Particle Physics CERN (Switzerland), Cyclotron Institute at Texas A&M University (USA), ExtreMe Matter Institute EMMI (Germany), Helmholtz Association and GSI under grant VH-NG-822 (Germany), Helmholtz International Center for FAIR (Germany), National Science Foundation (USA), Netherlands Organization for Scientific Research (Netherlands), Nuclear Physics Institute of the CAS (Czech Republic), the Ministry of Education, Youth and Sport (Czech Republic) and 3 sponsors who wish to remain anonymous.Javier López Albacete, Universidad de Granada (Spain)Jana Bielcikova, Nuclear Physics Inst. of the Czech Academy of Sciences (Czech Republic)Rainer J. Fries, Texas A&M University (USA)Jiangyong Jia, Stony Brook University and Brookhaven National Laboratory (USA)André Mischke, Utrecht University and Nikhef Amsterdam (The Netherlands)Hannah Petersen, Goethe University, FIAS and GSI (Germany)Lijuan Ruan, Brookhaven National Laboratory (USA)Sevil Salur, Rutgers University, (USA)

Conception and design of a control and monitoring system for the mirror alignment of the CBM RICH detector

The Compressed Baryonic Matter (CBM) experiment at the future Facility for Anti-proton and Ion Research (FAIR) will investigate the phase diagram of strongly interacting matter at high net-baryon density and moderate temperature in A+A collisions. One of the key detectors of CBM to explore this physics program is a Ring Imaging CHerenkov (RICH) detector for electron identification. For a high performance of the RICH detector precise mirror alignment is essential. A three-step correction cycle has been developed, which will be discussed: First a qualitative, fast check of the mirror positions, second a quantitative determination of possible misalignments and third a software correction routine, allowing a proper functioning of the RICH under misalignment conditions.

The optimised sc dipole of SIS100 for series production

At the international facility for antiproton and ion research (FAIR) in Darmstadt, Germany, an accelerator complex is developed for fundamental research in various fields of modern physics. In the SIS100 heavy-ion synchrotron, the main accelerator of FAIR, superconducting dipoles are used to bend the particle beam. The fast ramped dipoles are 3 m long super-ferric curved magnets operated at 4.5 K. The demands on field homogeneity required for sufficient beam stability are given by ΔB/B ≤ ±6 · 10−4. An intense measurement program of the First of Series (FoS) dipole showed excellent quench behavior and lower than expected AC losses yielding the main load on the SIS100 cryoplant. The FoS is capable to provide a field strength of 1.9 T. However, with sophisticated measurement systems slight distortions of the dipole field were detected. Those effects were tracked down to mechanical inaccuracies of the yoke proven by appropriate geometrical measurements and simulations. After a survey on alternative fabrication techniques a magnet with a new yoke was built with substantial changes to improve the mechanical accuracy. Its characteristics concerning cryogenic losses, cold geometry and the resulting magnetic-field quality are presented and an outlook on the series production of superconducting dipoles for SIS100 is given.

Design of versatile ASIC and protocol tester for CBM readout system

Silicon Tracking System (STS), Muon Chamber (MUCH) and Transition Radiation Detector (TRD) subdetectors in the Compressed Baryonic Matter (CBM) detector system at Facility for Antiproton and Ion Research (FAIR) use the same innovative protocol ensuring reliable synchronization of the communication link between the controller and the front-end ASIC, transmission of time-deterministic commands to the ASIC and efficient readout of data. The paper describes the FPGA-based tester platform which can be used both for the verification of the protocol implementation in a front-end ASIC at the design stage, and for testing of the produced ASICs. Due to its modularity, the platform can be easily adapted for different integrated circuits and readout systems.