| Paper | Title | Page |
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| TUPS01 | Rf-enhanced Schottky Signals from Electron-cooled Coasting Beams in a Heavy-Ion Storage Ring | |
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Measurements at the Test Storage Ring (TSR) of the Max Planck Institute for Nuclear Physics (MPIK) in Heidelberg, Germany, have shown that the signals from coasting, electron-cooled ion beams, picked up using a Schottky-noise electrode, can be significantly enhanced in amplitude by simultaneous exposure of the beams to an off-resonant radio frequency (rf) signal*. The detuning between the rf signal and the closest harmonic of the beam revolution frequency is so large that beam bunching is not possible. Thus no net locking of the average revolution frequency to an integer fraction of the rf occurs. Instead, the centre frequency of the pick-up signal closely follows the revolution frequency imposed onto the ions by the electron cooler of the storage ring. For beams of protons and bare carbon ions, this rf-perturbation resulted in up to 13-fold enhancement of the pick-up signal amplitude compared to the pure Schottky-noise spectrum of the electron-cooled beams. While the origin of this pick-up signal amplification is still under investigation, the technique is now routinely employed at the TSR in order to measure the revolution frequencies of low-current ion beams, whose unperturbed Schottky spectra are too faint to be detectable under normal circumstances.
* C. Krantz et al., NIM A 629 (2011), 1-5 |
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| TUPS02 | Booster Electron Cooling System of NICA Project | |
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| Nuclotron-based Ion Collider fAcility (NICA) is the new accelerator complex being constructed at the JINR. It includes the injection complex, existing superconducting proton synchrotron "Nuclotron", and the new superconducting proton synchrotrons – the Booster and the Collider. We plan to use in the NICA several cooling systems: electron cooling for the Booster and for the Collider, and stochastic cooling for the Collider. The Booster electron cooling system is designed for the electron energy range of 1.5 – 60 keV and maximum current of 1.0 A. The elements of electron cooling system (electron gun, collector, power supply system) will be tested at the test-bench "Recuperator" at the JINR. In the report the design and the basic parameters of the Booster electron cooling system are presented. | ||
| TUPS03 | Closed Orbit Correction in 2 MeV Electron Cooler Section at COSY-Juelich | 92 |
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| A 2 MeV magnetized electron cooling system will be installed in COSY to boost the luminosity for future high density internal target experiments. For an effective electron cooling, the proton beam and electron beam have to overlap coaxially, it lead to the necessity of a good orbit correction in cooler section. Since the toroid magnets, the proton beam orbit distortion is anti-symmetric in horizontal plane. With steerers at each side of cooler, the proton beam can be made coaxial in the cooler and the deflection can be compensated. The distortion caused by bending coils in toroid is symmetric in vertical plane. A four-bump method is suggested for correction. Using the magnetic field data measured in BINP, we calculated the orbit distortion of proton beam at injection energy, and investigated the scheme of closed orbit correction. The simulation of orbit distortion and result of the correction are presented in this paper. | ||
| TUPS05 | Simulation of High-Energy Electron Cooling at COSY with BETACOOL Program | 95 |
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| A 2 MeV electron cooling device will be installed at COSY in order to boost the luminosity of pellet target experiments. The magnetized electron cooling technique is used to compensate the energy loss and emittance growth for future COSY pellet target experiments. In this article, a numerical simulation of cooling process is performed with BETACOOL code. The cooling time is calculated for variant cooler setting parameters. The intrabeam scattering (IBS) and target effect are essential for prediction of equilibrium beam parameters. The influence of the pellet target on the beam parameters is demonstrated. | ||
| TUPS06 | Electron Gun with Variable Beam Profile for COSY Cooler | 99 |
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| Electron gun with variable beam profile is used on COSY 2 MeV cooler to optimize the cooling process. Further development of the gun is achieved with the help of the four-sector control electrode that provides some new features. Combined with BPMs it gives the possibility of the electron beam shape estimation. Application of the gun for stochastic cooling is also discussed in the article. | ||
| TUPS07 | Electron Collector for 2 MeV Electron Cooler for COSY | 103 |
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| New electron collector for 2 MeV electron cooler for COSY ring is presented. In electron coolers efficiency of collector is important for high voltage power supply. In 2 MeV cooler for COSY it is also important from the point of view of radiation safety because secondary electrons, reflected from the collector go back to accelerating tube. Besides radiation effect it can cause problems with vacuum and electric strength. The collector presented in the article is supplemented with Wien filter which allows increase efficiency of the system by deflection secondary electron flux in crossed transverse electric and magnetic fields. Results of calculation and experimental results achieved on special test bench are presented. | ||
| TUPS08 | System for Measurement of Magnetic Field Line Straightness in Solenoid of Electron Cooler for COSY | 107 |
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| Construction of measurement system is presented. The system is based on special magnetic sensor (compass) with a mirror attached to the compass needle. The needle with the mirror are suspended on gimbal suspension and can rotate in two directions. Measuring reflected laser beam deflection one can measure field line straightness with accuracy up to 10-6 rad. The compass is installed inside vacuum volume of the cooling section on special carriage that moves on rail along the section via special tape. To calibrate the compass special test bench was made. The calibration procedure allows to determine and to diminish compass inaccuracy appeared during manufacture and assembling. Results of calibration of the compass on the test bench are presented. | ||
| TUPS09 | LEPTA Project: Towards Positrons | 111 |
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| The Low Energy Positron Toroidal Accumulator (LEPTA) at JINR is under commissioning with circulating positron beam. The LEPTA facility is a small positron storage ring equipped with the electron cooling system and positron injector. The maximum positron energy is of 10 keV. The main goal of the project is generation of intensive flux of Positronium (Ps) atoms - the bound state of electron and positron, and setting up experiments on Ps in-flight. The report presents an advance in the project: up-grade of LEPTA ring magnetic system, status of the commissioning of positron transfer channel, the results of the electron cooling system tests, results of low energy positrons storage positron beam formation using Na22 radioactive positron source of radioactivity of 25 mCi. | ||
| TUPS10 | Magnetic System of Electron Cooler for COSY | 114 |
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| Cooler magnetic system for COSY is described. Electron beam energy range is wide (24 keV- 2 MeV), typical bending radiuses of electrons are near 1 m, typical magnetic fields are 0.5 – 2 kG. Under such conditions transport channels with longitudinal magnet field for motion of electrons from high voltage terminal of cascade transformer into cooling section and their return for recuperation are discussed. Results of Hall device measurements are compared with suitable computations. Also some steps were taken for improve of the magnetic field line straightness in the cooling section. | ||
| TUPS11 | Superconducting Shield for Solenoid of Electron Cooling System | 118 |
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| The homogeneity of the magnetic field in the straight solenoid of the electron cooling system is the very important task. The superconducting solenoids are planned for electron cooling systems of collider rings of NICA project. To reach the necessary homogeneity in the straight section the superconducting shield was proposed. The experimental and numerical investigations of the field homogeneity with the superconducting shield are presented. | ||
| TUPS12 | Optical Electron Beam Diagnostics for Relativistic Electron Cooling Devices | 121 |
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| For the cooling of proton and Ion beams a well established overlap between cooling beam and circulating beam is needed. The new relativistic electron cooling devices have special demands on the diagnostics which can be used to characterize the cooling beam. Due to high voltage breakdowns they only allow a very small beam loss so non-invasive beam diagnostic methods are necessary. A system based on beam induced uorescence (BIF) was installed at the 100 keV polarized test setup at the Mainzer Mikrotron (MAMI). First results of the measured photon yield as a function of beam current and residual gas pressure will be presented. In addition a Thomson scattering experiment is planned at the same test setup. This method enables the measurement of other observables of the cooling beam like the electron beam energy or the electron temperature. The design of the experiment as well as the challenges will be discussed. | ||
| TUPS13 | Electron Cooler for NICA Collider | 125 |
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| The electron cooling system at electron energy up to 2.5 MeV for the NICA collider is under design at JINR. The electron cooler is developed according to the available world practice of similar systems manufacturing. The main peculiarity of the electron cooler for the NICA collider is using of two cooling electron beams (one electron beam per each ring of the collider) that never has been done before. The acceleration and deceleration of the electron beams is produced by common high-voltage generator. The conceptual design of the electron cooling system has been developed. The cooler consist of three tanks. Two of them contain acceleration/deceleration tubes and are immersed in superconducting solenoids. The third one contains HV generator, which design is based on voltage multiplying scheme | ||
| TUPS14 | Simulation Study of Stochastic Cooling at CSRe IMP | |
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| The stochastic cooling of Radio Isotope beam is planned at the storage ring CSRe at the Institute of Modern Physics, Lanzohu in China. The stochastic cooling is planned as a pre-cooling of the electron cooling. The initial transverse emittance is assumed as 30 Pi mm.mrad, and the relative momentum spread is ± 5·10-3. The particle number is as small as 5·103. The palmer method is conceived as the PU and Kicker are installed at the finite dispersion section of the bending magnet chamber. In the present paper, details of simulation results of longitudinal and transverse cooling process are discussed. | ||
| TUPS15 | The Stochastic Cooling System of HESR | 129 |
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| The HESR is the high energy storage ring (1.5-15 GeV/c) for antiprotons at the FAIR facility (Facility for Antiprotons and Ion Research) in Darmstadt (GSI). Stochastic cooling in the HESR is necessary not only during the experiments to fulfill the beam requirements, but also during the accumulation due to the postponed RESR. Extensive simulations and prototype measurements have been carried out to optimize the HESR stochastic cooling system with the new slot-ring couplers. The system design is now in the final construction phase for the mechanical tank layout and all active RF-components. First results of the optical notch-filter with automated frequency control and the 4-6 GHz slot-ring couplers will be presented. | ||
| TUPS16 | An Improved Forward Travelling Wave Structure Design for Stochastic Cooling at Experimental Cooler Storage Ring (CSRe) at the Institute of Modern Physics (IMP) in China | 132 |
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| An improved forward travelling wave (TW) structure as the pick-up/kicker is designed for the stochastic cooling to match the field wave’s (phase) velocity to that of the beam. The theoretical analysis is performed together with the simulations of the propagation characteristics. Using CST Microwave Studio (CST MWS), the simulated results, including phase velocity, characteristics impedance, and distributions of the longitudinal fields, are implemented and compared with the experimented results. The improved forward TW structure can be satisfied the requirements of stochastic cooling project at CSRe, which the phase velocity is closed to 0.70 (matching the desired beam energy of 400 MeV/u) and the characteristics impedance is 17 ohm. | ||
| TUPS17 | Beam Dynamics Simulation in the X-ray Compton Source NESTOR | |
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| During the last several years, at the National Science Center "Kharkov Institute of Physics and Technology" the X-ray generator on the base of Compton back scattering NESTOR (New Electron STOrage Ring) are under construction now. The facility consists of the compact storage ring (operation energy range 40-225 MeV, circumference is equal to 15.4 m, 4 dipole magnets, 20 quadrupole and 19 sextupole lenses, RF resonator with operation frequency 699.3 MHz, operation pressure of residual gas 10-9 torr), linear electron accelerator as an injector (beam energy is equal to 35-90 MeV, bunch length 12 ps, pulse current 90-120 mA, energy spectrum 0.75%, emittance 0.07 mm*mrad), transportation system and laser-optical system (Nd:Yag laser, wavelength 1064 nm, average power >10 W, pulse duration ~ 10 ps, pulse repetition rate 350 MHz, optical cavity with accumulation rate of about 1000). The expected X-rays flux will be of about 1013 phot/s Theoretical investigations of electron beam dynamics in storage ring taking into account the interaction with intense laser beam have been carried out numerically using computer simulations with MAD and DeCA codes and analytically. In this report we represent the results of these investigations, the description and the status of X-ray generator NESTOR | ||
| TUPS18 | Quasi-Cooling of Electron Beam Under Asymmetric Collision at Compton Scattering | |
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| The simulation results of the Compton scattering of the laser photons on the electron beam in the storage ring at the asymmetric collision, when the centers of the longitudinal density distributions are not coincide, are presented. In the certain conditions one can essentially decrease the beam energy spread keeping the scattering intensity. The presented results may be useful in the design of the intense gamma – ray sources based on the Compton storage rings. | ||
| TUPS19 | Simulation Study of Barrier Bucket Accumulation with Stochastic Cooling at the GSI ESR | 136 |
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| The beam accumulation experiments with use of barrier bucket cavity and stochastic cooling was successfully performed at the ESR, GSI. The two methods of barrier voltage operation, moving barrier and fixed barrier cases were tried, and for some cases the electron cooling was additionally employed as well as the stochastic cooling. In the present paper, the beam accumulation process are simulated with particle tracking method where the cooling force (stochastic and electron cooling), the diffusion force and the barrier voltage force are included as well as the IBS diffusion effects. The simulation results are well in agreement with the experimental results. | ||
| TUPS20 | Demonstration of Longitudinal Stacking in the ESR with Barrier Buckets and Stochastic Cooling | 140 |
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| Fast longitudinal beam accumulation has been demonstrated in the ESR at GSI with an Ar18+ beam coming from the synchrotron SIS18 at 400 MeV/u. Continuous application of stochastic cooling in all three phase space directions, merges the stack with the new injected bunch. Longitudinal beam compression was achieved by using either short barrier bucket rf pulses or by successive injections onto the unstable fixed point of the rf bucket at h=1. This recent experiment in the ESR provides the proof of principle for the planned longitudinal stacking of pre-cooled antiprotons in the HESR, injected from the CR. | ||
| TUPS21 | The Nonlinear Transformation of a Ions Beam in the Plasma Lens | 144 |
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The plasma lens can carry out not only sharp focusing of ions beam. At those stages at which the magnetic field is nonlinear, formation of other interesting configurations of beams is possible. Plasma lens provides formation of hollow beams of ions in a wide range of parameters*. Application of the several plasma lenses allow to create some nontrivial spatial configurations of ions beams**: to get a conic and a cylindrical beams. The plasma lens can be used for transformation of beams with Gaussian distribution of particles density in a beams with homogeneous spatial distribution. The calculations showed that it is possible for a case of equilibrium Bennett's distribution of a discharge current . This requires a long duration of a discharge current pulse of > 10 mks. The first beam tests have essentially confirmed expected result. Calculations and measurements were performed for a C+6 and Fe+26 beams of 200-300 MeV/a.u.m. energy. The obtained results and analysis are reported.
* A. Drozdovskiy et al., IPAC'10, Kioto, Japan, http://cern.ch/AccelConf/IPAC10 /MOPE040. |
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| TUPS22 | Deceleration of Carbon Ions at the Heavy Ion Storage Ring TSR | 147 |
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| In order to evaluate the beam quality obtained after deceleration of 12C6+ ions at the heavy ion storage ring TSR, it is important to consider the possible sources of beam heating. In our experiments at the TSR Heidelberg carbon ions are injected at an energy of 73.3 MeV and decelerated them to 9.7 MeV in a cycle that includes two steps where beam cooling are applied. In this contribution we discuss the influences of intrabeam scattering (IBS) and the heating mechanisms on circulating ions. We will present results on the deceleration efficiency, the scaling of IBS rates with the beam energy and intensity, and studies of the phase space distribution during deceleration. |