An efficient, movable single-particle detector for use in cryogenic ultra-high vacuum environments

Abstract

A compact, highly efficient single-particle counting detector for ions of keV/u kinetic energy, movable by a long-stroke mechanical translation stage, has been developed at the Max-Planck-Institut für Kernphysik (Max Planck Institute for Nuclear Physics, MPIK). Both, detector and translation mechanics, can operate at ambient temperatures down to ∼10 K and consist fully of ultra-high vacuum compatible, high-temperature bakeable, and non-magnetic materials. The set-up is designed to meet the technical demands of MPIK's Cryogenic Storage Ring. We present a series of functional tests that demonstrate full suitability for this application and characterise the set-up with regard to its particle detection efficiency.

Single-particle detection of products from atomic and molecular reactions in a cryogenic ion storage ring

“…In a recent publication, we have presented the design of a movable single-particle counting detector for the Cryogenic Storage Ring (CSR) of the Max Planck Institute for Nuclear Physics (MPIK) in Heidelberg, Germany [30]. Here, we report on the first operation of this device under real-life experimental conditions at the CSR.…”

“…system has been described extensively in a dedicated publication [30], hence we limit ourselves to a brief overview here. Equipped with a 20-mm-wide entrance window for heavy particles, the detector is movable transversely to the beam direction in the plane of the storage ring.…”

“…By placement at a suitable horizontal position, the detector can intercept products with a charge-to-mass ratio that differs from that of the stored parent beam by more than 100 % in both directions. Specifically, it can detect neutral products on axis of the ion beam in the experiment as well as, e.g., ionisation products up to the double charge of a stored atomic cation beam [30].…”

“…At higher CSR operating temperatures, products of electron transfer from the residual gas to stored cations were observed. For testing purposes, the detector can be irradiated by photons from an ultra-violet (UV, 245(5) nm) light emitting diode (LED) [30]. The UV-LED is located in a room temperature annex of the CSR sector opposite of the detector.…”

“…1) is located downstream from an experimental section, within one of the ion-optics sectors of CSR. The technology of the detector [15] (top) and the COMPACT detector [30] (bottom). The lattice of CSR is a four-fold symmetric, approximately quadratic, and purely electrostatic beam-line, consisting of a total of eight 39 • deflectors (1), eight 6 • deflectors (2), and eight focussing quadrupole doublets (3).…”