Vladimir Reva

Electron cooling for RHIC

We introduce plans for electron-cooling of the Relativistic Heavy Ion Collider (RHIC). This project has a number of new features as electron coolers go: It will cool 100 GeV/nucleon ions with 50 MeV electrons; it will be the first attempt to cool a collider at storage-energy; and it will be the first cooler to use a bunched beam and a linear accelerator as the electron source. The linac will be superconducting with energy recovery. The electron source will be based on a photocathode gun. The project is carried out by the Collider-Accelerator Department at BNL in collaboration with the Budker Institute of Nuclear Physics.

COMMISSION OF ELECTRON COOLER EC-300 FOR HIRFL-CSR

HIRFL-CSR, a new ion accelerator complex, is under construction at IMP, Lanzhou, China. It is equipped with two electron cooling devices. This article describes the commissioning of cooler at electron energy 300 keV. The cooler is one of the new coolers with some unique manufactured in BINP, Russia. It has a new electron gun producing a hollow electron beam, electrostatic bending and a new structure of solenoid coils at the cooling section. The test results of cooler obtained in Novosibirsk and Lanzhou are reported.

Status of the R&D towards electron cooling of RHIC

The physics interest in a luminosity upgrade of RHIC requires the development of a cooling-frontier facility. Detailed calculations were made of electron cooling of the stored RHIC beams. This has been followed by beam dynamics simulations to establish the feasibility of creating the necessary electron beam. The electron beam accelerator will be a superconducting Energy Recovery Linac (ERL). An intensive experimental R&D program engages the various elements of the accelerator, as described by 24 contributions to the 2007 PAC.

Electron cooling experiments in CSR

The six species heavy ion beam was accumulated with the help of electron cooling in the main ring of Cooler Storage Ring of Heavy Ion Research Facility in Lanzhou(HIRFL-CSR), the ion beam accumulation dependence on the parameters of cooler was investigated experimentally. The 400MeV/u C and 200MeV/u Xe was stored and cooled in the experimental ring CSRe, the cooling force was measured in different condition.

Budker INP Proposals for HESR and COSY Electron Cooler Systems

The subject of the report is the problem of the technical feasibility of fast electron cooling in the energy range between 0.8 and 14.5 GeV. It is very useful for one of the major objectives of the GSI and COSY future plans. For the realization of the cooler device BINP team proposes the design that is like the conventional and elaborated for the low energy cooling (up to 300 keV). The main features of this design are the accelerating tube immersed in the magnetic field along the whole length and the strong magnetic field in the cooling section. The physics of electron cooling is based on the idea of the fast magnetized cooling. The cooling force at strong magnet field was measured at many experiments and can be surely estimated. The magnetized cooling rate enables to obtain the required beam parameters, eliminate the beam heating due to intrabeam scattering, fluctuations of ionization energy losses and multiple scattering in the internal target.

First recombination experiment of fluorine-like nickel ions at the main cooler storage ring

Absolute non-resonant recombination (RR) rate coefficients of Ni19+ ions were measured by employing the electron–ion merged-beams technique at the main cooler storage ring in Lanzhou. Using the electron cooler and energy detuning system, we obtained a narrow momentum spread (Δp/p ~ 2 × 10−4) and tuned precisely relative energies (minimum electron energy detuning step voltage 1 V) between electrons and ions. In addition, we compared the RR rate coefficients with the theoretical ones calculated by the self-consistent-field Dirac–Slater method, and found that they are in good agreement.

Vacuum pumping with an electron beam

The results of preliminary vacuum tests of an electron cooler with an electron beam that was designed for the LEIR lead-ion storage device (currently being built at CERN) are presented. The tests were performed at the Budker Institute of Nuclear Physics, Siberian Division, Russian Academy of Sciences (Novosibirsk, Russia). It has been shown that, after degassing the collector, injection of an electron beam improves the vacuum level in the setup.

First Tests of LEIR — Cooler at BINP

New electron cooling device was constructed for LEIR accumulator ring according to ILHC project at CERN. The cooler was designed, manufactured and completely tested with electron beam at BINP (Novosibirsk, Russia). Special features of the device and the results obtained are presented in the paper.

Recuperation of Electron Beam in the Coolers with Electrostatic Bending

An important aspect of the cooler operation is the collector efficiency. The low loss current improves the vacuum condition, the radiation condition and makes the easy design of the power supply system. This article deals with the reuse of collector at the electrostatic bending in the toroidal section. It’s possible to compensate the centrifugal force for the secondary electrons by the electric field because the effect of both forces is independent from the direction of the electron longitudinal velocity. As result the secondary electrons may return into the collector after reflection from the gun. Nonzero loss current is defined mainly by the energy spectrum of the secondary electrons. The review of the experimental data for the different cooler is described in this article. The range of the electron energy is 2 – 300 keV. Some physical model is proposed for the experiment explanations.

Space charge oscillation in electron cooling devices

Electron cooling is used for improving the parameters of ion beams. The cooling efficiency depends drastically on the space charge fluctuation intensity in the beam. The fluctuations present in the cooling region cause the stochastic heating of the ions, which adversely affects the cooling efficiency and may even annihilate the ion beam. The space charge fluctuation intensity as a function of various operating parameters of a cooler is studied experimentally. A mechanism of fluctuation generation is suggested, and the effect of fluctuations on the ion beam parameters is estimated.