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Title: The cryogenic storage ring CSR

Abstract

An electrostatic cryogenic storage ring, CSR, for beams of anions and cations with up to 300 keV kinetic energy per unit charge has been designed, constructed, and put into operation. With a circumference of 35 m, the ion-beam vacuum chambers and all beam optics are in a cryostat and cooled by a closed-cycle liquid helium system. At temperatures as low as (5.5 ± 1) K inside the ring, storage time constants of several minutes up to almost an hour were observed for atomic and molecular, anion and cation beams at an energy of 60 keV. The ion-beam intensity, energy-dependent closed-orbit shifts (dispersion), and the focusing properties of the machine were studied by a system of capacitive pickups. The Schottky-noise spectrum of the stored ions revealed a broadening of the momentum distribution on a time scale of 1000 s. Photodetachment of stored anions was used in the beam lifetime measurements. The detachment rate by anion collisions with residual-gas molecules was found to be extremely low. A residual-gas density below 140 cm{sup −3} is derived, equivalent to a room-temperature pressure below 10{sup −14} mbar. Fast atomic, molecular, and cluster ion beams stored for long periods of time in a cryogenic environment willmore » allow experiments on collision- and radiation-induced fragmentation processes of ions in known internal quantum states with merged and crossed photon and particle beams.« less

Authors:
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;  [1] more »; « less
  1. Max-Planck-Institut für Kernphysik, 69117 Heidelberg (Germany)
Publication Date:
OSTI Identifier:
22597965
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 87; Journal Issue: 6; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ANIONS; BEAM OPTICS; CATIONS; CRYOSTATS; DENSITY; ENERGY DEPENDENCE; FRAGMENTATION; HELIUM; ION BEAMS; ION PAIRS; KEV RANGE 100-1000; KEV RANGE 10-100; KINETIC ENERGY; LIQUIDS; PARTICLE BEAMS; PHOTONS; QUANTUM STATES; SPECTRA; STORAGE RINGS; TEMPERATURE RANGE 0273-0400 K

Citation Formats

Hahn, R. von, Becker, A., Berg, F., Blaum, K., Fadil, H., Fellenberger, F., Froese, M., George, S., Göck, J., Grieser, M., Grussie, F., Guerin, E. A., Herwig, P., Karthein, J., Krantz, C., Kreckel, H., Lange, M., Laux, F., Lohmann, S., Menk, S., and and others. The cryogenic storage ring CSR. United States: N. p., 2016. Web. doi:10.1063/1.4953888.
Hahn, R. von, Becker, A., Berg, F., Blaum, K., Fadil, H., Fellenberger, F., Froese, M., George, S., Göck, J., Grieser, M., Grussie, F., Guerin, E. A., Herwig, P., Karthein, J., Krantz, C., Kreckel, H., Lange, M., Laux, F., Lohmann, S., Menk, S., & and others. The cryogenic storage ring CSR. United States. doi:10.1063/1.4953888.
Hahn, R. von, Becker, A., Berg, F., Blaum, K., Fadil, H., Fellenberger, F., Froese, M., George, S., Göck, J., Grieser, M., Grussie, F., Guerin, E. A., Herwig, P., Karthein, J., Krantz, C., Kreckel, H., Lange, M., Laux, F., Lohmann, S., Menk, S., and and others. 2016. "The cryogenic storage ring CSR". United States. doi:10.1063/1.4953888.
@article{osti_22597965,
title = {The cryogenic storage ring CSR},
author = {Hahn, R. von and Becker, A. and Berg, F. and Blaum, K. and Fadil, H. and Fellenberger, F. and Froese, M. and George, S. and Göck, J. and Grieser, M. and Grussie, F. and Guerin, E. A. and Herwig, P. and Karthein, J. and Krantz, C. and Kreckel, H. and Lange, M. and Laux, F. and Lohmann, S. and Menk, S. and and others},
abstractNote = {An electrostatic cryogenic storage ring, CSR, for beams of anions and cations with up to 300 keV kinetic energy per unit charge has been designed, constructed, and put into operation. With a circumference of 35 m, the ion-beam vacuum chambers and all beam optics are in a cryostat and cooled by a closed-cycle liquid helium system. At temperatures as low as (5.5 ± 1) K inside the ring, storage time constants of several minutes up to almost an hour were observed for atomic and molecular, anion and cation beams at an energy of 60 keV. The ion-beam intensity, energy-dependent closed-orbit shifts (dispersion), and the focusing properties of the machine were studied by a system of capacitive pickups. The Schottky-noise spectrum of the stored ions revealed a broadening of the momentum distribution on a time scale of 1000 s. Photodetachment of stored anions was used in the beam lifetime measurements. The detachment rate by anion collisions with residual-gas molecules was found to be extremely low. A residual-gas density below 140 cm{sup −3} is derived, equivalent to a room-temperature pressure below 10{sup −14} mbar. Fast atomic, molecular, and cluster ion beams stored for long periods of time in a cryogenic environment will allow experiments on collision- and radiation-induced fragmentation processes of ions in known internal quantum states with merged and crossed photon and particle beams.},
doi = {10.1063/1.4953888},
journal = {Review of Scientific Instruments},
number = 6,
volume = 87,
place = {United States},
year = 2016,
month = 6
}
  • At the Max-Planck-Institut fuer Kernphysik in Heidelberg a next generation electrostatic storage ring for cryogenic temperatures is under development. The main focus of this unique machine is the research on ions, molecules and clusters up to bio molecules in the energy range of 20-300 keV at low temperatures down to 2 Kelvin. The achievement of this low temperature for all material walls seen by the ions in the storage ring will allow novel experiments to be performed, such as rotational and vibrational state control of molecular ions and their interaction with ultra-low energy electrons and laser radiation. The low temperaturemore » of the storage ring not only causes a strong reduction of black body radiation incident onto the stored particles, but also acts as a large cryopump, expected to lead to a vacuum in the 10-15 mbar range. In this paper the cryogenic concept of the storage ring and the related vacuum design will be presented.« less
  • The cryogenic and vacuum concepts for the electrostatic Cryogenic ion Storage Ring (CSR), under construction at the Max-Planck-Institut fuer Kernphysik in Heidelberg, is presented. The ring will operate in a broad temperature range from 2 to 300 K and is required to be bakeable up to 600 K. Extremely high vacuum and low temperatures are necessary to achieve long lifetimes of the molecular ions stored in the ring so that the ions will have enough time to cool by radiation to their vibrational and rotational ground states. To test cryogenic and vacuum technological aspects of the CSR, a prototype ismore » being built and will be connected to the commercial cryogenic refrigerator recently installed, including a specialized 2-K connection system. The first results and the status of current work with the prototype are also presented.« less
  • We describe the design of a novel type of storage device currently under construction at Stockholm University, Sweden, using purely electrostatic focussing and deflection elements, in which ion beams of opposite charges are confined under extreme high vacuum cryogenic conditions in separate ''rings'' and merged over a common straight section. The construction of this double electrostatic ion ring experiment uniquely allows for studies of interactions between cations and anions at low and well-defined internal temperatures and centre-of-mass collision energies down to about 10 K and 10 meV, respectively. Position sensitive multi-hit detector systems have been extensively tested and proven tomore » work in cryogenic environments and these will be used to measure correlations between reaction products in, for example, electron-transfer processes. The technical advantages of using purely electrostatic ion storage devices over magnetic ones are many, but the most relevant are: electrostatic elements which are more compact and easier to construct; remanent fields, hysteresis, and eddy-currents, which are of concern in magnetic devices, are no longer relevant; and electrical fields required to control the orbit of the ions are not only much easier to create and control than the corresponding magnetic fields, they also set no upper mass limit on the ions that can be stored. These technical differences are a boon to new areas of fundamental experimental research, not only in atomic and molecular physics but also in the boundaries of these fields with chemistry and biology. For examples, studies of interactions with internally cold molecular ions will be particular useful for applications in astrophysics, while studies of solvated ionic clusters will be of relevance to aeronomy and biology.« less
  • The cross sections for the processes e/sup +/e/sup -/..--> pi../sup +/..pi../sup -/..pi../sup +/..pi../sup -/ and e/sup +/e/sup -/..--> pi../sup +/..pi../sup -/..pi../sup +/..pi../sup -/..pi../sup 0/ have been measured in the energy range 2E = 1019--1403 MeV with the cryogenic magnetic detector (CMD) at the VEPP-2M electron-positron storage ring. The limit B(phi..--> pi../sup +/..pi../sup -/..pi../sup +/..pi../sup -/..pi../sup 0/)<1.5 x 10/sup -4/ has been obtained at the 95% confidence level. At the energy 2E = 1403 MeV, the cross section sigma = 0.26 +- 0.12 nb for the reaction e/sup +/e/sup -/..--> pi../sup +/..pi../sup -/..pi../sup +/..pi../sup -/..pi../sup 0/..pi../sup 0/ has been measured, andmore » a limit sigma<45 pb on the cross section for e/sup +/e/sup -/..--> pi../sup +/..pi../sup -/..pi../sup +/..pi../sup -/..pi../sup +/..pi../sup -/ has been obtained at the 95% confidence level.« less