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Topic 2: "Cosmic Matter in the Laboratory"

Infrastructures

The topic Cosmic Matter in the Laboratory exploits accelerators, particle detectors at storage rings and for fixed-target experiments and significant computing resources. The major ones are:

 

  • The COSY synchrotron at the Forschungszentrum Jülich (FZJ) is a cooler and storage ring with unique characteristics and capabilities. It can provide phase-space cooled proton and deuteron beams with momenta up to 3.7 GeV/c. These particles, which may also be polarised, are either stored in the ring for internal experiments or extracted to be used at external target stations. Cooling and beam-diagnostics techniques have been developed over the years for hadron physics in unpolarised and in single and double polarised experiments. These are now being exploited in accelerator and detector tests to prepare devices and methods for the High Energy Storage Ring (HESR) and the PANDA and CBM facilities at FAIR. In addition, spin manipulation and detection possibilities are widely used for studying polarisation build-up through spin-filtering (PAX-at-COSY) as well as R&D for planned searches for Electric Dipole Moments (EDM) of charged particles in storage rings (collaborations: US-based srEDM, FZJ-based JEDI).

 

  • The JSC centre provides high-performance computer capacity for scientists at the Forschungszentrum Jülich (FZJ), at universities and research laboratories in Germany and in Europe - as well as for industrial partners. The scientific peer review is done by the John von Neumann Institute for Computing (NIC). This comprises the operation and especially the development of the supercomputers and the technical infrastructure, the data storage, visualisation systems, networks and software. A further important task is the user support and education: at JSC, students can be trained to be mathematical-technical software developers and simultaneously take the bachelor study course "Scientific Programming". Within the research topic Matter and the Universe, JSC is heavily exploited for data storage from COSY experiments (ANKE; PAX and WASA) and for spin tracking simulations in connection with the EDM project JEDI.

 

  • UNILAC, SIS18 and ESR: The GSI accelerator facility consists of the linear accelerator UNILAC, the heavy-ion synchrotron SIS18, the experimental storage-cooler ring ESR and experimental facilities. With these facilities, intense ion beams of all elements from hydrogen up to the heaviest, uranium, can be accelerated to energies from the Coulomb barrier up to 2 GeV/u. Secondary radioactive ion beams are available as well as highly ionised atoms up to bare uranium nuclei. Due to the construction of FAIR only very limited operation periods will be offered during the PoF 3-period. The accelerator will primarily be used for FAIR accelerator and detector tests. The UNILAC and the SIS18 are the main injectors for FAIR.

 

  • HADES is a charged particle detector with large acceptance and high rate capability operated at SIS18. It can investigate pion, proton and ion induced reactions. The combination of a low-mass tracking system with a RICH, a pre-shower and time-of-flight detectors enables in particular rare dielectron measurements.

  • Testbeam facility at MAMI-C: University Mainz operates a 1.6 GeV electron accelerator on the campus of the University for hadron physics studies and tests of fundamental symmetries. Electrons from 14 MeV beam energy up to 1.6 GeV from very low currents up to 100 μA can be used with variable energy for the test of all kinds of detector components and radiation-hardness tests. The R&D development for the PANDA electromagnetic calorimeter and the PANDA DIRC detector would not have been possible without the availability of this beam. In addition, MAMI-C provides a beam of energy-marked photons in the same energy range.

 

  • LHC and the experiment ALICE: Together with several German universities, GSI holds the responsibility for the ALICE Time Projection Chamber (TPC), the Transition Radiation Detector (TRD), and the High Level Trigger (HLT). In terms of physics analysis the ALICE group at GSI has many coordination roles, and has contributed substantially to most of the 70 articles published in refereed scientific journals by the ALICE Collaboration.

 

  • TRIGA reactor: University Mainz operates a TRIGA reactor. It produces reactor neutrons in continuous and pulsed mode. It is used for nuclear physics research, pharmaceutical applications and for the production of ultracold stored neutrons. The isotope production beam line is used for experiments where rare, neutron-rich isotopes are trapped and used in spectroscopy experiments. It is an important instrument for the preparation of trapping techniques which have applications at GSI and FAIR.

 

  • GSI compute cluster: GSI operates a high-performance computing cluster for the research groups working at GSI and their international collaborators. The HPC-Cluster consists of 12,000 CPUs and offers disk storage space of 10 Petabytes. The HPC-Cluster provides compute power for running detector simulations and theory model code for experiments at the GSI accelerators. Furthermore it provides storage for experimental data and analysis results. It provides support for the national research groups participating in international collaborations e.g. operation of a TIER 2 centre for the ALICE experiment at CERN. Scientific and technical preparation of FAIR accelerator components and experiments is another important application of the GSI compute cluster e.g. detector simulations and accelerator optics calculations, running theoretical codes in the field of e.g. nuclear structure, hadron structure, heavy-ion microscopic transport and lattice gauge theory.

 

 

Future Infrastructures

In the topic Cosmic Matter in the Laboratory, the planned infrastructures within the FAIR-project, comprising accelerators, storage rings and detectors, are well underway. In addition, it is planned to perform a proof-of-principle measurement for the search of charged-particle EDMs (proton and deuteron) in storage rings with COSY.

 

  • FAIR: The international Facility for Antiproton and Ion Research is a unique accelerator facility comprising a large suite of detector systems for research with antiprotons and ions, now being built near Darmstadt. A key feature is a highly sophisticated and cost-effective accelerator layout that will allow the parallel and versatile production of an unprecedented range of particle beams.

    In its final stage the facility is centered around two large synchroton rings (SIS100 and SIS300), 1,100 meters in circumference to accelerate ions — from protons to uranium. The existing accelerators, UNILAC and SIS18, will pre-accelerate the ions before they are injected into the first ring SIS100. A new proton linear accelerator will be built to inject high-intensity proton beams. The high-energy proton and ion beams will be used either directly or to create secondary beams of antiprotons and also of stable and unstable (radioactive) ions, the latter separated in flight exploiting a novel Super Fragment Separator. Coupled to the SIS100/300 rings is a complex of further rings into which the beams are guided, and then accelerated, stored and refined for specific experiments.

    FAIR will be built in a staged way. The Modularized Start Version, currently under construction, will comprise the SIS100 accelerator, several rings, and detector systems for all four scientific pillars of FAIR: the CBM, NUSTAR and PANDA collaborations are briefly described below; the NUSTAR, PANDA, and APPA collaboration, focussing on research in atomic, plasma and biophysics as well as material sciences, is mainly located in the Helmholtz program From Matter to Materials and Life.

 

  • CBM: The Compressed Baryonic Matter (CBM) experiment will be one of the 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. The CBM detector is designed to measure both bulk observables with large acceptance and rare diagnostic probes such as charmed particles and vector mesons decaying into lepton pairs. GSI Darmstadt plays a leading role in the coordination and organisation of the CBM collaboration which comprises about 500 scientists and engineers from 55 institutes and 12 countries. Groups from GSI are responsible for the design and construction of the Silicon Tracking System (STS) which is the central detector system of the CBM experiment. Moreover, the front-end electronics for several detectors and the data acquisition system are being developed at GSI, as well as the simulation and data analysis framework. GSI is also responsible for the infrastructure of the experimental area.

 

  • NUSTAR is a collaboration that concentrates on theory and experiments for nuclear structure, astrophysics, reactions and superheavy element research. Experiments are carried out at the UNILAC and the SIS of GSI using the separators SHIP, TASCA and FRS and specialised detector systems. A superconducting continuous-wave linear accelerator (cw-linac) is under development, which will provide twenty times higher intensity-stable beams for the superheavy-element synthesis programme. For NUSTAR at FAIR, the Super-FRS will be the central instrument for the whole collaboration. It will provide intense beams of relativistic exotic nuclei to the large detector systems HISPEC/DESPEC, MATS/LaSPEC, R3B, and ILIMA, which are located at its three branches. The Super-FRS itself will provide unique experimental opportunities for high-resolution spectrometer experiments.

 

  • PANDA: is a planned detector system at the FAIR facility that will investigate various topics around the weak and strong forces, exotic states of matter and the structure of hadrons. The detector will use a cluster-jet or a pellet target as an internal target in the HESR storage ring for antiprotons. The interaction point will be surrounded by precision tracking detectors for both precision momentum reconstruction as well as vertex resolution sufficient for open charm reconstruction. This will be surrounded by particle identification and an electromagnetic calorimeter with, e.g. a factor four higher light output than achieved for CMS at CERN due to cooling the system to –25°C and recent improvements in the production process. These detectors will be placed inside a solenoid field. At low polar angles, a dipole-based spectrometer will be used to analyse the forward particles.

 

  • HESR: The HESR synchrotron, part of the FAIR project, is dedicated to the field of high-energy antiproton physics with high-quality beams over the broad momentum range from 1.5 to 15 GeV/c to explore the research areas of hadron structure and quark–gluon dynamics. An important feature of the new facility is the combination of phase-space-cooled beams with internal targets which opens new capabilities for high-precision experiments. The 575-m-long HESR is designed as a racetrack-shaped storage ring with a magnetic bending power of 50 Tm, including 132 m-long straight sections. One of these sections will be used for installation of an internal target and the sophisticated PANDA detector, the other will house cooling equipment. Two other experimental groups (ASSIA and PAX) expressed interest in spin physics experiments at the HESR. In the HESR design, sufficient space is reserved to allow an upgrade for polarised beams.

 

  • CW-linac: A dedicated continuous wave linear accelerator (cw-linac) for intense heavy-ion beams, consisting of multi-cavity superconducting cryo-modules, is under development. in combination with an upgraded GSI High Charge Injector (HLI). It is one of the projects in the Helmholtz Roadmap. The cw-linac will provide continuous-wave time structure as opposed to the existing accelerator and intensities which are up to twenty times higher than today, while low ion-source material consumption, especially for enriched materials, will be maintained.

 

  • Precursor EDM storage ring using COSY: An important — maybe decisive — intermediate step towards a dedicated precision EDM storage ring (with clock-wise and counter clock-wise beams) will be to establish the method to search for charged particle EDMs in an existing conventional ring. COSY can be exploited for such a precursor experiment, but in order to change from its current use as a hadron physics machine to a precision spin-physics device, a number of measures must be taken in order to reach the targeted EDM sensitivities. In order to significantly reduce systematic errors, the required COSY modi cations include an improved closed-orbit control system for the correction of the beam orbit in the micrometer range. This requires an increase in the stability of correction-dipole power supplies by at least one order of magnitude. The number of correction dipoles and beam-position monitors (BPMs) must be increased, since the orbit has to be controlled along the entire path length of the beam in the COSY machine. The accuracy of the BPMs must also be improved. The interaction of the circulating beam with the surrounding vacuum chamber produces longitudinal and transverse wake fields, which can lead to transverse and longitudinal beam kicks and excite instabilities. An accurate estimation of the total impedance budget of the COSY machine must be carried out, and, depending on the outcome, those sections in conflict with the goals of this proposal will have to be modified. Monitoring the spin direction changes of the beam will require a more efficient polarimeter that contains a thicker extraction target and a new set of forward-angle detectors to cover elastic scattering between 5° and 10°. Better regulation of the machine RF will be required. Finally, construction techniques must be mastered that will allow electric field plates to be installed in the COSY ring and provide steady state or oscillating electric fields up to 20 MV/m. As a start, and in order to gain experience, FZJ and FNAL (Fermilab) have agreed to transfer Tevatron deflectors to COSY.

 

Future Infrastructures common to all three topics

Essential upgrades of some existing infrastructures are expected to take place in the forthcoming PoF period. Two of these planned infrastructures are of concern to all three topics of the programme Matter and the Universe:

 

  • LHC detector upgrades: The LHC physics programme is designed for a period of at least 20 years to fully exploit its scientific potential. The corresponding necessary luminosity evolution has been laid down and entails particle rates and occupancies that some of the LHC detector components will not be able to stand; in particular the currently installed ATLAS and CMS tracking detectors will have reached the end of their lifetimes by 2020. Fortunately, technological progress has indicated solutions that will be able to overcome this challenge. These cutting-edge technologies, that are still the subject of research, have to be verified in detector system installations to eventually be used in upgrades for the LHC detectors. Similarly, the longstanding systematic approach of exploring novel detectors for applications at a future e+e collider will greatly benefit from system-level installations.

    DESY, GSI and KIT have demonstrated in the past their ability to construct large detectors in-house, a capability that is indispensable for the LHC upgrades. These institutes are prepared to assume a leading role in the construction of major detector systems. Consequently, a proposal for investment funds of 28 million euros to be submitted in autumn 2014 has been prepared that will permit Helmholtz participation in the construction of new large detector components. The Helmholtz centres serve as integration centres for the German and international community.

    For DESY, the centrepiece of this proposal is the construction of silicon strip end-caps for ATLAS and CMS. DESY plans to serve as a detector integration hub in the consortium with German universities and other international partners. DESY will produce a large fraction of the required detector modules and the support structures. The necessary investment for this endeavour amounts to 20 million euros and is vital for the success of the future LHC programme at DESY and subject of the proposal to Helmholtz. DESY will contribute an additional 5.5 million euros from non-strategic funding for setting up the necessary laboratory infrastructure in the form of a Detector Assembly Facility in the coming years.

    KIT proposes to use its expertise in detector readout systems to become a key partner in the upgrade of the CMS silicon tracker readout system and to develop, prototype and produce a significant part of the new readout and track-finding system in close collaboration with international partners. For this purpose, funds amounting to 3.8 million euros have been requested.

    With the continuation of the ALICE program, GSI aims to stay in the worldwide leadership in the study of ultra-relativistic heavy ion collisions. Together with several German universities, GSI holds the responsibility for the ALICE Time Projection Chamber (TPC), and the High-Level Trigger (HLT). GSI will in a leading way participate in the upgrade of the TPC end-caps to GEM readout, thereby also establishing this technology within the Helmholtz Association. GSI will further play an important role in adapting the HLT to online calibration and tracking, with important implications for experiments at FAIR. Altogether, the GSI share in the LHC detector upgrade proposal is 4.2 million euros.

 

  • Tier-1 and Tier-2 Computing for the future LHC: The discovery of a comparatively light Higgs particle has brought a new challenge for LHC computing — physics analyses now demand that the sensitivity for decay leptons of quite low transverse momentum be fully preserved. Therefore, thresholds can no longer be increased in order to reduce the data volume. In addition, the luminosity of the LHC machine will be significantly increased after the the currently ongoing long shutdown LS1. The recorded data volumes will thus increase significantly. The experiments have already responded in refining their triggers and in balancing the loads. However, after the long shutdown LS1 the computing installations will have to be significantly augmented to match the challenge.

    Therefore, in addition to the LK II (performance category 2) proposal for the third funding period, DESY, GSI and KIT are preparing a large-investment proposal for a total funding of 33.1 million euros for a period of five years. It is planned to adapt both the Tier-1 and Tier-2 computing capabilities for all four LHC experiments to the increased needs. On the GridKa Tier-1 side, this requires increased storage and processing capabilities and adaptions to the evolved computing models of the LHC experiments as well as of the future Belle II experiment.

    On the Tier-2 side, funding would support both the Tier-2 centre at GSI (ALICE) and the Tier-2 centre and National Analysis Facility, NAF at DESY (ATLAS, CMS, LHCb); in addition, contributions to the maintenance of Tier-2 installations at universities that provide a significant portion of the current Tier-2 compute capability in Germany would be funded.