| Paper | Title | Other Keywords | Page |
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| MOPEA049 | Application of Particle Accelerators to High Energy Density Physics Research: The HEDgeHOB Collaboration | ion, target, simulation, plasma | 184 |
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Intense particle beams lead to volumetric heating of solid targets that generates large samples of High Energy Density (HED) matter. Such samples are very suitable to study the thermophysical properties of this important state of matter that spans over numerous fields of basic and applied physics. Facility for Antiprotons and Ion Research (FAIR) at Darmstadt, will generate very powerful bunched beams of the heaviest particles (uranium) that will deposit unprecedented high levels of specific power in the target. Extensive theoretical work has been carried out over the past decade to design HED physics experiments at the FAIR. So far, four different experimental schemes have been proposed. These include, HIHEX (Heavy Ion Heating and Expansion, which is suitable to study equation-of-state properties of HED matter), LAPLAS (Laboratory Planetary Science, which is suitable to generate physical conditions that exist in the interiors of the giant planets), Study of the growth of the Richtmyer-Meshkov instability and finally , the ion beam driven Ramp Compression which is suitable to study material properties like shear modulus and yield strength, under dynamic conditions. |
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| MOPEA051 | Preliminary Design of the AEGIS Test Facility | positron, vacuum, cryogenics, target | 190 |
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The AEGIS experiment is expected to be installed at the CERN Antiproton Decelerator in a very close future, since the main goal of the AEGIS experiment is the measurement of gravity impact on antihydrogen, which will be produced on the purpose. Antihydrogen production implies very challenging environmental conditions: at the heart of the AEGIS facility 50 mK temperature, 10-12 mbar pressure and a 1 T magnetic field are required. Interfacing extreme cryogenics with ultra high vacuum will affect very strongly the design of the whole facility, requiring a very careful mechanical design. This paper presents an overview of the actual design of the AEGIS experimental facility, paying special care to mechanical aspects. Each subsystem of the facility - ranging from the positron source to the recombination region and the measurement region - will be shortly described. The ultra cold region, which is the most critical with respect to the antihydrogen formation, will be dealt in detail. The assembly procedures will be considered too, as they are expected to be critical to make the set-up phase easier, as well as to make possible any future improvement of the facility itself. |
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| MOPD024 | Scintillating Screen Studies for Low Energy, Low Intensity Beams | proton, ion, monitoring, diagnostics | 729 |
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Future atomic and nuclear physics experiments put challenging demands on the required beam instrumentation. Low energy (<1 MeV), low intensity (<107 pps) beams will require highly sensitive monitors. This is especially true for the Facility for Low-energy Antiproton and Ion Research (FLAIR) where antiproton beams will be decelerated down to 20 keV and as few as 5·105 particles per second will be slowly extracted for external experiments. In order to investigate the limits of scintillating screens for beam profile monitoring in the low energy, low intensity regime a structured analysis of several screen materials, including CsI:Tl, YAG:Ce and scintillating fibre optic plate (SFOP), has been done under different irradiation conditions with keV proton beams. This contribution will present the experimental setup and summarize the results of this study. |
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| MOPD067 | Status of the 2 MeV Electron Cooler for COSY/ HESR | electron, vacuum, high-voltage, solenoid | 843 |
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The 2 MeV electron cooling system for COSY-Jülich was proposed to further boost the luminosity even in presence of strong heating effects of high-density internal targets. The project is funded since mid 2009. Manufacturing of the cooler components has already begun. The space required for the 2 MeV cooler is being made available in the COSY ring. The design and construction of the cooler is accomplished in cooperation with the Budker Institute of Nuclear Physics in Novosibirsk, Russia. The 2 MeV cooler is also well suited in the start up phase of the High Energy Storage Ring (HESR) at FAIR in Darmstadt. It can be used for beam cooling at injection energy and is intended to test new features of the high energy electron cooler for HESR. Two new prototypes of the modular high voltage system were developed, one consisting of gas turbines the other based on inductance-coupled cascade generators. The new 2 MeV electron cooler is described in detail and tests of components are reported. |
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| MOPD075 | Effect of Secondary Ions on the Electron Beam Optics in the Recycler Electron Cooler | ion, electron, focusing, quadrupole | 867 |
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AAntiprotons in Fermilab's Recycler ring are cooled by a 4.3 MeV, 0.1 ' 0.5 A DC electron beam (as well as by a stochastic cooling system). The unique combination of the relativistic energy (γ = 9.49), an Ampere - range DC beam, and a relatively weak focusing makes the cooling efficiency particularly sensitive to ion neutralization. A capability to clear ions was recently implemented by way of interrupting the electron beam for 1-30 μs with a repetition rate of up to 40 Hz. The cooling properties of the electron beam were analyzed with drag rate measurements and showed that accumulated ions significantly affect the beam optics. For a beam current of 0.3 A, the longitudinal cooling rate was increased by factor of ~2 when ions were removed. |
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| MOPE001 | A Tank Circuit Monitoring a Large Number of Antiprotons in MUSASHI | electron, rfq, plasma, resonance | 948 |
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In Antiproton Decelerator (AD) at CERN, unique low energy antiproton beams of 5.6 MeV have been delivered for physics experiments. Furthermore, the RFQ decelerator (RFQD) dedicated for Atomic Spectroscopy And Collisions Using Slow Antiprotons (ASACUSA) collaboration enables the use of 100 keV pulsed antiproton beams for experiments. What is more, Mono-energetic Ultra Slow Antiproton Source for High-precision Investigations (MUSASHI) in ASACUSA can produce antiproton beams with the energy of 100 ~ 1000 eV. Since the successful extraction of 250 eV antiproton beams reported in 2005, continuous improvements on beam quality and equipments have been conducted. Here, the basic properties of a tank circuit attached to MUSASHI trap are reported. Signals from a tank circuit provide information on the trapped antiprotons, as Shottky signals do for high energy beams in accelerators. In fact, it is known that this kind of trap-based beams are physically equivalent with those in a FODO lattice. Monitoring the tank circuit signals will be useful for on-line handling of the low energy antiproton beams from MUSASHI. |
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| MOPE054 | Design of a 1.42 GHz Spin-Flip Cavity for Antihydrogen Atoms | cavity, vacuum, proton, sextupole | 1095 |
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The hyperfine transition frequency of hydrogen is known to a very high precision and therefore the measurement of this transition frequency in antihydrogen is offering one of the most accurate tests of CPT symmetry. The ASACUSA collaboration will run an experiment designed to produce ground state antihydrogen atoms in a CUSP trap. These antihydrogen atoms will pass with a low rate in the order of 1 per second through a spin-flip cavity where they get excited depending on their polarization by a 1.42 GHz magnetic field. Due to the small amount of antihydrogen atoms that will be available the requirement of good field homogeneity is imposed in order to obtain an interaction with as many antihydrogen atoms as possible. This leads to a requirement of an RF field deviation of less than ± 10 % transverse to the beam direction over a beam aperture with 100 mm diameter. All design aspects of this new spin-flip cavity, including the required field homogeneity and vacuum aspects, are discussed. |
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| MOPE061 | Gas Electron Multipliers for Low Energy Beams | electron, cathode, extraction, high-voltage | 1116 |
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Gas Electron Multipliers (GEM) find their way to more and more applications in beam instrumentation. Gas Electron Multiplication uses a very similar physical phenomenon to that of Multi Wire Proportional Chambers (MWPC) but for small profile monitors they are much more cost efficient both to produce and to maintain. This paper presents the new GEM profile monitors intended to replace the MWPCs currently used at CERN's low energy Antiproton Decelerator (AD). It will be shown how GEMs overcome the documented problems of profile measurements with MWPCs for low energy beams, where the interaction of the beam with the detector has a large influence on the measured profile. Results will be presented from profile measurements performed at 5 MeV using four different GEM prototypes, with discussion on the possible use of GEMs at even lower energies needed at the AD in 2012. |
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| TUPEA038 | A Digital Baseband Low Level RF Control for the P-linac Test Stand at GSI | controls, cavity, linac, proton | 1413 |
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During the redesign of the low level RF system for the S-DALINAC, a baseband approach was chosen. The RF signals from/ to the cavity are converted into the baseband via I/Q Modulators/ Demodulators. The advantage of this design was realized lateron, as adaption of other frequencies becomes rather easy. The system, originally designed for 3 GHz superconducting cavity in cw operation is currently modified to control a 324 MHz room temperature CH cavity in pulsed operation. We will report on the rf control system principle, the required modifications and first results. |
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| TUPD070 | Progress with Tevatron Electron Lens Head-on Beam-Beam Compensation | electron, betatron, proton, gun | 2084 |
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Tevatron electron lenses have been successfully used to mitigate bunch-to-bunch differences caused by long-range beam-beam interactions. For this purpose the electron beam with uniform transverse density distribution was used. Another planned application of the electron lens is the suppression of tune spread due to head-on beam-beam collisions. For this purpose, the transverse distribution of e-beam must be matched to that of the antiproton beam. In 2009, the gaussian profile electron gun was installed in one of the Tevatron electron lenses. We report on the first experiments with non-linear beam-beam compensation. Discussed topics include measurement and control of the betatron tune spread, importance of the beam alignment and stability, and effect of the electron lens on the proton and antiproton beam lifetime. |
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| WEPEB013 | IFC to FESA Gateway: Smooth Transition from GSI to FAIR Control System | controls, status, site, ion | 2710 |
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Present GSI control system uses an in-house developed CORBA based middleware called IFC. For FAIR project that will be build on the GSI site, a new control system is foreseen. New devices that are being integrated into the control system preferably will be developed in FESA. In this article, an IFC to FESA gateway will be presented. The gateway provides an intermediate layer that is able to talk to FESA device servers on one side and provide their functionality to existing IFC clients. The gateway will allow coexistence of FESA front-end implementations and existing GSI device servers, providing a smooth transition path to the future FAIR front-end environment. New GSI and FAIR devices that will be implemented in FESA will have to match GSI standards for nomenclature and device modeling. Exact match of new devices is not possible due to different hardware and software architecture of the new system, therefore a gateway solution is required. The gateway can translate the complete device model, including conversion from FESA to GSI data types. In the process of gateway design and implementation, valuable input was collected for the design of the future FAIR control system. |
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| THPEC038 | The Concept of Antiproton Accumulation in the RESR Storage Ring of the FAIR Project | accumulation, injection, simulation, storage-ring | 4140 |
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In the complex of the accelerators of the FAIR project the RESR storage ring is mainly designed as an accumulator ring for antiprotons. The continuous accumulation of pre-cooled batches with a cycle time of 10 s from the collector ring is essential to achieve the goal of a production rate of 10 million antiprotons per second. The accumulation in the RESR uses a stochastic cooling system which operates in longitudinal phase space, similar as previous antiproton accumulator rings at CERN and FNAL. The ingredients of the accumulation system, the ring lattice functions, the electrode design and the electrical circuits have been studied in detailed simulations. A system has been found which safely provides the required performance and offers the option of upgrades, if higher accumulation rate is required in future. Maximum intensities of 100 billion cooled antiprotons are planned which are expected to stay below the instability threshold. |
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| THPEC040 | Design and Shielding of a Beamline from ELENA to ATRAP using Electrostatic Quadrupole Lenses and Bends | solenoid, shielding, quadrupole, emittance | 4146 |
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The construction of the Extra Low ENergy Antiprotons (ELENA) upgrade to the Antiproton Decelerator (AD) ring has been proposed at CERN to produce a greatly increased current of low energy antiprotons for various experiments including, of course, anti-hydrogen studies. This upgrade involves the addition of a small storage ring and electrostatic beam lines. 5.3 MeV antiproton beams from AD are decelerated down to 100 keV in the compact ring and transported to each experiment apparatus. In this paper, we describe an electrostatic beam line from ELENA to ATRAP and magnetic shielding of the low-energy beam line against the ATRAP solenoid magnet. A possible design of this system is displayed. |
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| THPEC058 | Development of MUSASHI, a Mono-energetic Ultra-slow Antiproton Beam Source | extraction, rfq, electron, plasma | 4188 |
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The ASACUSA collaboration at CERN has been developed a unique Mono-energetic Ulta-Slow Antiproton beam Source for High-precision Investigation (MUSASHI) for collision studies between antiproton and atoms at very low energy region, which also used as an intense ultra-low energy antiproton source for the synthesis of antihydrogen atoms in order to test CPT symmetry. MUSASHI consists of a multi-ring electrode trap housed in a bore surrounded by a superconducting solenoid, which works with a sequential combination of the CERN Antiproton Decelerator and the Radio-Frequency Quadrupole Decelerator. GM-type refrigerators were used to cool the solenoid and also the bore at 4K to avoid losses of antiprotons with residual gasses. Up to 1.8 millions of antiprotons per one AD cycle were successfully trapped and cooled. MUSASHI achieved to accumulate more than 12 millions of cold antiprotons by stacking several AD shots. Such cooled antiprotons were extracted as 150 or 250eV beams with various bunch lengths from 2 micoroseconds to 30 seconds long, whose energy width was the order of sub-eV. The beam intensity was enhanced by a radial compression technique for the trapped antiproton cloud. |
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| THPD052 | Manipulation of Negatively Charged Beams via Coherent Effects in Bent Crystals | scattering, alignment, secondary-beams, simulation | 4398 |
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New results in coherent interaction of negatively-charged particles with bent crystals showed unprecedentedly and significantly high efficiency to manipulate such beams, in the same way as for positively charged particles. Key feature under experimental attainment was the usage of high-quality suitably thin silicon crystals. We experimentally tested crystals Vs. 150 GeV negative pions at external lines of CERN SPS. We observed planar channeling at full deflection angle 30% high single-pass efficiency and large acceptance (about 20μrad). Moreover in the axial case, we reached more than 90% deflection efficiency and larger acceptance (about 60μrad). We also observed volume reflection in a bent crystal, at more than 70% single-pass efficiency with such a wide acceptance as the bending angle. At last, volume reflection by several planes in a single bent crystal was successfully tested with very high efficiency (about 80%). In summary both channeling and volume reflection modes appear to be useful technique for the manipulation of negatively charged beams, e.g. for collimation in the new generation of high intensity accelerators. The UA9 collaboration |
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| THPE015 | Simplified Approach to Evaluation of Beam-beam Tune Spread Compression by Electron Lens | electron, simulation, alignment, proton | 4545 |
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One of the possible ways to increase luminosity of hadron colliders is the compensation of beam-beam tune-spread with an electron lens (EL). At the same time, EL as an additional nonlinear element in the lattice can increase strength of nonlinear resonances so that its overall effect on the beam lifetime will be negative. Time-consuming numerical simulations are often used to study the effects of the EL. In this report we present a simplified model, which uses analytical formulae derived for certain electron beam profiles. Based on these equations the idealized shapes of the compressed tune spread can be rapidly calculated. Obtained footprints were benchmarked against several reference numerical simulations for the Tevatron in order to evaluate the selected configurations. One of the tested criteria was the so-called "folding" of the compensated footprint, which occurs when particles with different betatron amplitudes have the same tune shift. Also studied were the effects of imperfections, including misalignment of the electron and proton beams, and mismatch of their shapes. |