Facility For Antiproton And Ion Research Research Articles

FAIR SIS100 accelerating RF system - Modeling and analysis of the coupled LLRF control loops

The SIS100 heavy ion synchrotron as core part of the Facility for Antiproton and Ion Research (FAIR) will be equipped with 14 accelerating RF stations in the first stage of realization. Each RF station consists of a tunable ferrite-loaded cavity powered by a tetrode amplifier. Further key components are a solid-state pre-amplifier, a power supply unit, and dedicated Low-Level Radio Frequency (LLRF) feedforward and feedback systems to control amplitude and phase of the cavity gap voltage as well as the resonance frequency. Each cavity has to provide up to 20 kV peak gap voltage in the frequency range from 1.1 to 3.2 MHz. While all components of the system have been successfully tested in the factory acceptance tests and transferred to the FAIR storage, the First-of-Series (FoS) RF station is still persistently operated at GSI to gain experience. For further insight into the LLRF part, especially the stability of the control loops, the inter-coupling of the three local control loops was analyzed with methods from control theory based on simplified but realistic models, which have been developed based on extensive measurements and analysis of the systems’ behavior. In this contribution, the modeling as well as the analysis of the coupling between the LLRF control loops are discussed and the results are presented in comparison with measurements on the FoS system.

Quench detection electronics for FAIR

The SIS100 synchrotron and the Super-FRS fragment separator are the core machines of the Facility for Antiproton and Ion Research (FAIR), currently under construction in Darmstadt, Germany. A uniform quench detection system will ensure monitoring of superconducting magnets of both SIS100 and Super-FRS. Further, Plasma Physics and Applications (APPA) experiments will also make use of it.The distributed quench detection system of FAIR is based on hundreds of quench detection units. Their design, testing experience and first operational results are presented in this work.

Toward an environmental friendly operation of the CBM-TOF system

The future fixed target high-rate compressed baryonic matter (CBM) experiment is one of the experimental pillars of the Facility for Antiproton and Ion Research (FAIR) located in Darmstadt/Germany. In order to provide an excellent particle identification (PID) of charged hadrons, the CBM-time-of-flight (TOF) group has developed a concept of a 120 m2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^2$$\\end{document} large TOF wall with a system time resolution below 80 ps based on multi-gap resistive plate chambers (MRPC). Currently, timing MRPC systems are operated with a gas mixture based on tetrafluoroethane (R134a, C2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$_2$$\\end{document}H2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$_2$$\\end{document}F4\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$_4$$\\end{document}) with additions of few vol% quencher gases, e.g., sulfur hexafluoride (SF6\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$_6$$\\end{document}) or/and isobutane (i-C4\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$_4$$\\end{document}H10\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$_10$$\\end{document}). Unfortunately, these gas mixtures have a high global warming potential (GWP) in the order of 1500, and therefore, strategies to reduce the environmental impact have to be developed. The various possibilities, including studies on eco-friendly gases, and the considered strategy by the CBM-TOF group will be elaborated in this article.

Status of the development of the RICH detector for CBM including a mRICH prototype in mCBM

The Compressed Baryonic Matter (CBM) experiment is being built at the future Facility for Antiproton and Ion Research (FAIR) next to GSI, Darmstadt, Germany. A RICH detector will provide clean and efficient electron identification in order to access di-electrons emitted from dense baryonic matter, one of the key measurements of CBM. The CBM RICH recently passed the threshold to construction with first mass production of part of the electronics. The readout electronics was developed together with the HADES experiment and is successfully operated there in the upgraded RICH detector which also makes use of approximately half of the H12700 MAPMTs of CBM. The readout electronics is also tested in a dedicated “mini-RICH” detector in the “mini-CBM” setup with prototypes of all subdetectors, however with an implementation of the full functionality of the future free-streaming readout. Besides finalizing the RICH readout, work is ongoing on full size prototypes of the RICH mirror mechanics and the photocamera including a full system test of the cooling concept. In this report, a brief update on the various developments and the status of the CBM RICH detector is given.

A high-resolution asymmetric von Hamos spectrometer for low-energy X-ray spectroscopy at the CRYRING@ESR electron cooler

We present research program and project for high-resolution wavelength-dispersive spectrometer dedicated to low-energy X-ray spectroscopy at the electron cooler of the CRYRING@ESR storage ring, which is a part of the international Facility for Antiproton and Ion Research (FAIR) currently being built in Darmstadt. Due to the unique shape of the electorn-ion recombination X-ray source, resulting from the overlapping of the electron and ion beams in the electron cooler, the spectrometer can work in the specific asymmetric von Hamos (AvH) geometry. In order to completely eliminate the influence of Doppler effect on the measured X-ray energies, two asymmetric von Hamos spectrometers will be installed next to the dipole magnets on both sides of the electron cooler to detect blue/red (0°/180°) shifted X-rays, e.g. emitted in the radiative recombination (RR) process. The X-ray-tracing Monte-Carlo simulations show that the proposed AvH spectrometer will allow to determine with sub-meV precision, the low-energy X-rays (5–10 keV) emitted from stored bare or few-electron heavy ions interacting with cooling electrons. This experimental precision will enable accurate studies of the quantum electrodynamics (QED) effects in mid-Z H- and He-like ions.

Batch testing and noise rate optimization of MRPC3b for CBM-TOF/STAR-eTOF

The Compressed Baryonic Matter (CBM) experiment is one of the major scientific spectrometers of the future Facility for Antiproton and Ion Research (FAIR) in Darmstadt. As one of the core sub-systems in CBM experiment for charged hadron identification, the Time-of-Flight (TOF) system is required to have a time resolution better than 80 ps. According to the final state particle flux distribution, the CBM-TOF will be constructed with several types of Multi-gap Resistive Plate Chambers (MRPC). In the outer region of the TOF wall where the particle fluxes are around 1 kHz/cm2, MRPCs with ultra-thin float glass electrodes are considered as a cost effective solution. MRPC3b prototypes have been developed and tested with excellent performance which could meet all the requirements. Before the construction of CBM-TOF, approximately 80 MRPC3bs are assembled for the STAR endcap TOF (STAR-eTOF) upgrade at RHIC as part of the FAIR Phase-0 programs for CBM-TOF which provides a valuable opportunity for detector stability test under high flux environments. This paper will introduce the batch test of the MRPC3bs for STAR-eTOF upgrade. Time resolution of better than 70 ps and efficiency of around 95% are achieved. Notably, during the batch test, it has been observed that the noise rates of the two edge strips in each counter are significantly higher than those of the middle strips. Simulations with Computer Simulation Technology (CST) Studio Suite are carried out and several kinds of MRPC prototypes are designed and tested accordingly. Based on the simulation and test results, the design of the MRPC3b has been further optimized by modify the shape and position of High-Voltage injection pad and increasing the distance between the glass edge and both end strips, resulting in a significant suppression of noise rates in the edge strips.

Superconducting Dipoles for Super-FRS: Design, Production, First Measurements

The Super FRS is a two-stage in flight separator to be built next to the site of GSI, Darmstadt, Germany as part of FAIR (Facility for Anti-proton and Ion Research). Its purpose is to create and separate rare isotope beams and to enable access for very short-lived nuclei. Due to its three branches, a wide variety of experiments can be carried out in frame of the NUSTAR collaboration. Due to the large acceptance needed, the magnets of the Super-FRS have to have a large aperture and therefore only a superconducting solution is feasible. The dipole magnets are of superferric design in which the magnetic field is produced by superconducting coils and shaped by the iron yoke. This warm yoke weighs about 50 tons and stays at room temperature; the cryostat with the superconducting coils is embedded into the yoke. The conceptual design of the dipole was developed by CEA, the manufacturing is done by Elytt Energy (Spain), testing takes place at a dedicated test facility at CERN (Switzerland) by a GSI-team in frame of a collaboration contract. In this work we detail the main design features, the production of the first magnets and their testing results.

Elliptic flow of identified hadrons in Au+Au collisions at E_{lab} = 35~text {A}~text {GeV} using the PHSD model

We present predictions of elliptic flow (v_2) of identified hadrons at mid-rapidity (|y| < 1.0) in Au+Au collisions at E_{lab} = 35~text {A}~text {GeV} using the Parton Hadron String Dynamics (PHSD) model. The transverse momentum (p_{textrm{T}}) dependence of identified hadron v_2 in minimum bias (0–80%) and three different centrality intervals (0–10%, 10–40%, and 40–80%) are presented. A clear centrality dependence of v_2(p_{textrm{T}}) is observed for particles and anti-particles. We also present the p_{textrm{T}} dependence of v_2 difference ({Delta } v_2) between particles and corresponding anti-particles. A significant difference in v_2 values for baryons and anti-baryons is observed. Constituent quark scaling (NCQ) of v_{2} is investigated in Au+Au collisions. We also present a v_2(p_{textrm{T}}) ratio between the HSD and PHSD modes to explore the effect of hadronic and partonic interactions in the medium. These predictions are useful for interpreting the data measured in the Beam Energy Scan (BES) program at RHIC. They will also be useful for the future Compressed Baryonic Matter (CBM) experiment at the Facility for Antiproton and Ion Research (FAIR) and Multi-Purpose Detector (MPD) at the Nuclotron-based Ion Collider facility (NICA).

Resistive plate chambers for precise measurement of high-momentum protons in short range correlations at R[formula omitted

The Reactions with Relativistic Radioactive Beams (R3B) collaboration of the Facility for Antiproton and Ion Research (FAIR) in Darmstadt, Germany, has constructed an experimental setup to perform fundamental studies of nuclear matter, using as a probe reactions with exotic nuclei at relativistic energies. Among the various detection systems, one of the most recent upgrades consists of the installation of a large area, around 2 m2, multi-gap Resistive Plate Chamber (RPC). The chamber is equipped with twelve 0.3mm gaps and readout by 30mm pitch strips, exhibiting a timing precision down to 50 ps and efficiencies above 98% for minimum ionizing particles in a previous characterization of the detector. The RPC was part of the setup of the FAIR Phase 0 experiment that focused on measuring for the first time, in spring 2022, nucleon–nucleon short-range correlations (SRC) inside an exotic nucleus (16C). The excellent timing precision of this detector will allow the measurement of the forward emitted proton momentum with a resolution of around 1%. In beam measurements show an RPC efficiency above 95% and a time precision better than 100 ps (including the contribution of a reference scintillator and the momentum spread of the particles) for forward emitted particles.

Development and performance studies of a real size Resistive Plate Chamber tested at GIF＋＋, CERN for CBM-MuCh at FAIR, Germany

In the year 2016, Resistive Plate Chambers (RPCs) were proposed to be used as muon detectors in the 3rd and 4th stations of the Muon Chamber (MuCh) detector set-up of the under construction Compressed Baryonic Matter (CBM) experiment at the Facility for Anti-proton and Ion Research (FAIR) in Darmstadt, Germany. Since then, sincere efforts are being given to develop suitable detectors for this purpose with major challenges being the capability to handle high particle rates and perform well under harsh radiation environments. We have developed and tested a real size RPC along with its dedicated PCB and electronics read-out chain in GIF＋＋ under intense photon flux for its muon detection capability. In this manuscript, we have presented the test results of the RPC tested during November-2021 beam time in GIF＋＋, CERN, Switzerland.

Performance test of a position sensitive planar germanium detector for phase-III DESPEC experiments

The position sensitivity of a planar segmented double-sided germanium strip detector, with 10 × 10 electrical segmentation in orthogonal directions, has been studied using the coincidence method. The coincidences were set up between an imaging scanner and the PSPGe (Position Sensitive Planar Germanium) detector using a positron source, 22Na, and analyzed by employing the Positron Annihilation Correlation principle. A collimated 241Am source scan was also performed to find position resolution along X and Y axes using low energy gamma-ray source. The primary objective of this work is to study the charge carrier transportation for gamma-ray interactions inside the PSPGe detector. In order to select the electrodes of interest and to obtain the pulse shapes for each event, two-dimensional images have been processed. The net charge induced on the surface of the electrode, calculated using the pulse shape analysis procedure, has been used to profile the position resolution and gamma interaction depth. The present study is an input for the deployment of PSPGe detector in the future decay spectroscopy experiments to be performed at the Facility for Antiproton and Ion Research (FAIR) in Germany. This work investigates the gamma interaction depth by calculating the rise-time of traces stored for each gamma interaction inside the detector volume, providing ≈1 mm resolution along the depth. The position resolution of the detector in lateral directions, determined using the amplitude difference of the transient charges, has also been found to be ≈1 mm.

The compressed baryonic matter (CBM) experiment at FAIR—physics, status and prospects

The Compressed Baryonic Matter (CBM) experiment is one of the major scientific pillars of the Facility for Antiproton and Ion Research (FAIR). The physics programme of CBM is centred around the exploration of the QCD phase diagram and nuclear matter equation-of-state in the region of high baryon densities. The respective rare probes will be accessed by using nucleus-nucleus collisions in the energy range at peak interaction rates of up to 10 MHz and a trigger-less data acquisition scheme. This article reviews CBM physics goals with the experimental observables. The progress and current status (as of January 2022 before sanctions imposed on Russia and suspension of collaboration with Russian institutes) of the comprising detector sub‐systems, including their performance in FAIR Phase‐0 experiments will also be presented.

Direct Photon Production in Heavy-Ion Collisions: Theory and Experiment

Direct photons provide a possibility to test properties of hot matter created in proton–proton (pp), proton–nucleus (p–A) or nucleus–nucleus (A–A) collisions. As they are created in charged particles’ scatterings and freely escape the hot region, they provide a tool to test all stages of the collision: the scattering of the partons of incoming nucleons, pre-equilibrium evolution and collective expansion of hot quark–gluon matter created in nucleus–nucleus collisions. Comparing direct photon production in pp, p–A and A–A collisions, one can check the scaling with the number of binary collisions expected at a high transverse momentum range and obtain insight into the hot and cold hadronic matter properties with soft photons. The collective elliptic flow of direct photons is a unique possibility to trace the collective flow formation and space–time evolution of the fireball. We review the experimental results on direct photon production in pp, p–A and A–A collisions at the Super Proton Synchroton (SPS), the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC) energies and discuss an agreement of theoretical predictions with measurements. Finally, we present predictions of direct photon spectra and collective flow for lower energy collisions expected at the Nuclotron-based Ion Collider fAcility (NICA) and the Facility for Antiproton and Ion Research (FAIR).

Production of diamond using intense heavy ion beams at the FAIR facility and application to planetary physics

Diamonds are supposedly abundantly present in different objects in the Universe including meteorites, carbon-rich stars as well as carbon-rich extrasolar planets. Moreover, the prediction that in deep layers of Uranus and Neptune, methane may undergo a process of phase separation into diamond and hydrogen, has been experimentally verified. In particular, high power lasers have been used to study this problem. It is therefore important from the point of view of astrophysics and planetary physics, to further study the production processes of diamond in the laboratory. In the present paper, we present numerical simulations of implosion of a solid carbon sample using an intense uranium beam that is to be delivered by the heavy ion synchrotron, SIS100, that is under construction at the Facility for Antiprotons and Ion Research (FAIR), at Darmstadt. These calculations show that using our proposed experimental scheme, one can generate the extreme pressure and temperature conditions, necessary to produce diamonds of mm3 dimensions.

Study of a possible silicon photomultiplier based readout of the large plastic scintillator neutron detector NeuLAND

The NeuLAND (New Large-Area Neutron Detector) plastic-scintillator-based time-of-flight detector for 0.1–1.6GeV neutrons is currently under construction at the Facility for Antiproton and Ion Research (FAIR), Darmstadt, Germany. In its final configuration, NeuLAND will consist of 3,000 2.7m × 5 cm × 5 cm big plastic scintillator bars that are read out on each end by fast timing photomultipliers.Here, data from a comprehensive study of an alternative light readout scheme using silicon photomultipliers (SiPM) are reported. For this purpose, a NeuLAND bar was instrumented on each end with a SiPM-based prototype of the same geometry as a 1” photomultiplier tube, including four 6 × 6mm2 SiPMs, amplifiers, high voltage supply, and microcontroller.Tests were carried out using the 35MeV electron beam from the superconducting Electron Linac for beams with high Brilliance and low Emittance (ELBE) with its picosecond-level time jitter in two different modes of operation, namely parasitic mode with one electron per bunch and single-user mode with 1–60 electrons per bunch. Acqiris fast digitisers were used for data acquisition. In addition, off-beam tests using cosmic rays and the NeuLAND data acquisition scheme have been carried out.Typical time resolutions of σ≤ 120ps were found for ≥95% efficiency for minimum ionising particles, improving on previous work at ELBE and exceeding the NeuLAND timing goal of σ< 150ps. Over a range of 10–300MeV deposited energy in the NeuLAND bar, the gain was found to deviate by ≤10% (≤20%) from linearity for 35μm (75μm) SiPM pitch, respectively, satisfactory for calorimetric use of the full NeuLAND detector. The dark rate of the prototype studied was found to be lower than the expected cosmic-ray induced background in NeuLAND.

Technical design report for the endcap disc DIRC * *Antiproton annihilations at Darmstadt.

PANDA (anti-proton annihiliation at Darmstadt) is planned to be one of the four main experiments at the future international accelerator complex FAIR (Facility for Antiproton and Ion Research) in Darmstadt, Germany. It is going to address fundamental questions of hadron physics and quantum chromodynamics using cooled antiproton beams with a high intensity and and momenta between 1.5 and 15 GeV/c. PANDA is designed to reach a maximum luminosity of 2 × 1032 cm−2 s. Most of the physics programs require an excellent particle identification (PID). The PID of hadronic states at the forward endcap of the target spectrometer will be done by a fast and compact Cherenkov detector that uses the detection of internally reflected Cherenkov light (DIRC) principle. It is designed to cover the polar angle range from 5° to 22° and to provide a separation power for the separation of charged pions and kaons up to 3 standard deviations (s.d.) for particle momenta up to 4 GeV/c in order to cover the important particle phase space. This document describes the technical design and the expected performance of the novel PANDA disc DIRC detector that has not been used in any other high energy physics experiment before. The performance has been studied with Monte-Carlo simulations and various beam tests at DESY and CERN. The final design meets all PANDA requirements and guarantees sufficient safety margins.

Effect of various particlization scenarios on anisotropic flow and particle production using UrQMD hybrid model

We discuss the effect of various particlization scenarios available in the hybrid ultrarelativistic quantum molecular dynamics (UrQMD) event generator on different observables in non-central (b = 5–9 fm) Au + Au collisions in the beam energy range 1A-158A GeV. Particlization models switch fluid dynamic description to the transport description using various hypersurface criteria. In addition to particlization models, various equations-of-state (EoS) provided by the UrQMD hybrid model were employed. The observables examined in this paper include the excitation function of anisotropic coefficients such as directed (v1) and elliptic flow (v2), particle ratios of the species, and the shape of net-proton rapidity spectra at mid-rapidity. Our findings in this article suggest which particlization scenario among gradual freeze-out (GF, default), isochronous freeze-out(ICF), and iso-energy density freeze-out(IEF) hypersurface, is more reasonable in predicting the available experimental results. The results obtained here can help predict and compare the measurements provided by future experiments at the Facility for Antiproton and Ion Research (FAIR) and the Nuclotron-based Ion Collider fAcility (NICA) once the data becomes available.

The PANDA EDD prototype in Giessen Cosmic Station

The PANDA detector at the future Facility for Antiproton and Ion Research (FAIR) is currently being constructed in Darmstadt, Germany. It contains a fixed proton target and an antiproton beam with a momentum range between 1.5 GeV/c to 15 GeV/c. Two Cherenkov detectors are used to identify charged hadrons. The Disc DIRC (EDD) covers polar angles between 5° to 22° in the endcap region. In order to test the performance of the EDD prototype, the experimental setup driven by cosmic muons was built at the JLU in Giessen. It is called the Giessen Cosmic Station (GCS) and contains four tracking boxes for tracking muons, two trigger plates, and a lead absorber. The prototype of the EDD detector is integrated to the GCS setup to reconstruct the Cherenkov angle of each muon tracked by the GCS hodoscope.This work covers the technical design of the GCS and the performance tests of the EDD prototype in the GCS.

Landau damping of transverse head-tail instabilities with a pulsed electron lens in hadron synchrotrons

A pulsed electron lens produces a betatron tune shift along a hadron bunch as a function of the longitudinal coordinates, which is a longitudinal detuning. An example of transverse detuning is the tune shifts due to octupole magnets. This paper considers a pulsed electron lens as a measure to mitigate the head-tail instabilities. Using a detailed analytical description within a Vlasov formalism, the coherent properties of the longitudinal and transverse detuning are presented. The analytical predictions are compared with the results of the particle tracking simulations. A pulsed electron lens is demonstrated to be a source of tune spread with two components: a static one, leading to Landau damping and a dynamic one, leading to an effective impedance modification, which we demonstrate analytically and in our particle tracking simulations. The effective impedance modification can be important for beam stability due to devices causing longitudinal detuning, especially for nonzero head-tail modes. The Vlasov formalism is extended to include the combination of longitudinal and transverse detuning. As a possible application at the SIS100 heavy-ion synchrotron [Facility for Antiproton and Ion Research (FAIR) at GSI Darmstadt, Germany], a combination of a pulsed electron lens with octupole magnets is considered.

Real-Time Data Processing Pipeline for Trigger Readout Board-Based Data Acquisition Systems

Large-scale physics experiments running at high interaction rates place a high demand on the data acquisition system (DAQ) responsible for transporting the data from the detector to the storage. The antiProton ANihilation at DArmstadt (PANDA) at the facility for anti-proton and ion research (FAIR) is one such experiment of the future that will not use fixed hardware triggers; instead, the event selection is based on real-time feature extraction, filtering, and high-level correlations. A firmware framework for such real-time data processing has been developed and tested with hardware setup for a PANDA Forward Tracker (FT) prototype. The solution is applicable for other detector subsystems based on the so-called Trigger Readout Board (TRB) data read-out system.