V. Varentsov

Khlopin Radium Institute, Sankt-Peterburg, St.-Petersburg, Russia

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Publications (8)5.76 Total impact

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    ABSTRACT: A pulsed supersonic gas jet target for experiments at the HITRAP facility at the GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt has been designed and built as a multi-purpose installation for key experiments on fundamental atomic physics in strong fields. This setup is currently installed at the Institut für Kernphysik of Goethe-University, Frankfurt am Main (IKF), in order to explore its operation prior to its installation at the HITRAP facility. Design and performance of the target are described. The measured target densities of 5.9×1012 atoms/cm3 for helium and 8.1×1012 atoms/cm³ for argon at the stagnation pressure of 30 bar match the required values. The target-beam diameter of 0.9 mm and the pulsed operation mode (jet built-up-time ≤15 ms) are well suited for the use at HITRAP.
    Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment 11/2014; 764:387–393. · 1.14 Impact Factor
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    ABSTRACT: HITRAP is a facility for very slow highly-charged heavy ions at GSI. HITRAP uses the GSI relativistic ion beams, the Experimental Storage Ring ESR for electron cooling and deceleration to 4 MeV/u, and consists of a combination of an interdigital H-mode (IH) structure with a radiofrequency quadrupole structure for further deceleration to 6 keV/u, and a Penning trap for accumulation and cooling to low temperatures. Finally, ion beams with low emittance will be delivered to a large variety of atomic and nuclear physics experiments. Presently, HITRAP is in the commissioning phase. The deceleration of heavy-ion beam from the ESR storage ring to an energy of 500 keV/u with the IH structure has been demonstrated and studied in detail. The commissioning of the RFQ structure and the cooler trap is ongoing.
    Journal of Physics Conference Series 12/2009; 194(14):142007.
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    ABSTRACT: An ion-catcher device consisting of a buffer-gas stopping cell and a radio-frequency quadrupole (RFQ) has been built for the SHIPTRAP facility at GSI. Results of characterisation measurements with the buffer-gas cell and the extraction RFQ performed at GSI in Darmstadt and at the MLL (Maier-Leibnitz-Laboratory) in Garching are presented. The set-up was tested off-line using laser-produced ions and on-line using stable beams and fusion–evaporation products. During the on-line measurements the ions with total energies of around 200 keV/u were thermalised in helium buffer gas at 40–60 mbar. In the following they were guided by a combination of electric RF- and DC-fields until they were transported by the gas flow through the extraction nozzle. After being extracted by a supersonic gas jet the ions were separated from the buffer gas and guided by the extraction RFQ towards subsequent detection systems. Depending on the electric-field strength average extraction times of around 10 ms and an overall efficiency (including stopping and extraction) between 4% and 8% have been achieved.
    Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms. 01/2006;
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    ABSTRACT: The goal of the low-energy-beam and ion-trap (LEBIT) project is to convert the high-energy exotic beams produced at NSCL/MSU into low-energy low-emittance beams. This beam manipulation will be done by a combination of a high-pressure gas stopping cell and a radio-frequency quadrupole ion accumulator and buncher. The first experimental program to profit from the low-energy beams produced will be high-accuracy mass measurements on very short-lived isotopes with a 9.4 T Penning trap system. The status of the project is presented with an emphasis on recent stopping tests range of 100 MeV/A 40Ar18+ ions in a gas cell.
    Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms 05/2003; 204:507-511. · 1.19 Impact Factor
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    ABSTRACT: We are investigating a new concept of a buffer gas filled ion cooler built from single radio frequency (RF) ring electrodes. In such a ring electrode structure, the RF potential generates an average repelling short-range force perpendicular to the electrode surfaces. Due to the composition of single rings, the shape of the cooling channel can easily and smoothly be varied, and hence also the direction of the RF forces. As a result, the angular acceptance can be increased by a factor of two in comparison to the maximum acceptance for the present RF quadrupole coolers.
    Journal of Physics B Atomic Molecular and Optical Physics 02/2003; 36(5):971. · 2.03 Impact Factor
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    ABSTRACT: The ion trap facility SHIPTRAP is installed behind the separator for heavy ion reaction products (SHIP) at GSI, which is well known for the discovery of new super-heavy elements produced in cold fusion reactions. SHIPTRAP consists out of a gas cell for stopping the recoil ions delivered by SHIP and two linear radio frequency quadrupole (RFQ) structures for cooling and accumulating the ions. In a first Penning trap the radionuclides of interest get further cooled and isobaric contaminants are removed. The second Penning trap is intended for high-precision mass measurements or identification of the stored ions before providing them to further downstream experiments. During a first on-line experiment in 2001, ions from SHIP were stopped in the gas cell and transferred into the RFQ structures. Accumulation and cooling could be demonstrated.
    Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms 01/2003; · 1.19 Impact Factor
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    ABSTRACT: The Low Energy Beam and Ion Trap (LEBIT) project will convert high-energy ( 100 MeV/A) fragmentation beams into very low emittance, low energy (5 keV) beams. These brilliant beams are requisite for high precision experiments. In particular, they will be used for high precision mass measurements of short-lived species. To facilitate the conversion to a low energy beam, a high-pressure (1 bar) gas cell is utilized. To be extracted from the gas cell, the ions must pass through the 1 mm inner diameter nozzle at the end of the gas cell. After the gas cell, a series of three linear radio-frequency quadrupole (RFQ) ion guides carry the ions through differential pumping and into high vacuum. In contrast to similar systems used elsewhere we plan to drive these RFQs with square waves, which greatly simplifies the tuning and operation. In order to find optimum geometrical and operational parameters, ion trajectories were calculated based upon a combination of ion optics and gas flow. Our calculations show efficient transport through the system.
    10/2002;
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    ABSTRACT: SHIPTRAP is an electromagnetic transport and trapping system to provide very clean and cold beams of singly-charged recoil ions from the SHIP facility at GSI. The different components of the system are currently under development in Munich (gas cell and extraction RFQ) and GSI (Buncher RFQ and Penning traps)[1]. Design and manufacturing of the prototype buffer gas cell and the extraction RFQ based on a wide range of simulations have been completed. The results of these simulations together with the first measurements will be reported.
    Hyperfine Interactions 12/2000; 132(1):501-505. · 0.21 Impact Factor