Supersonic Gas Jet Target Research Articles

Status Report on the Internal Gas-Jet Target for the Heavy-Ion Storage Ring CRYRING

A supersonic gas-jet target for investigations of the detailed collision dynamics in fast ion-atom collisions by means of recoil-ion-momentum spectroscopy has been constructed for insertion into the heavy-ion storage ring CRYRING, situated at the Manne Siegbahn Laboratory, Stockholm University. The aim is to create a target with a density of 1012 cm-3 and a temperature of less than 10 mK (for the case of a He target) without seriously affecting the excellent vacuum conditions of CRYRING. The gas target will become a part of the storage ring, and hence fast beams of protons, highly-charged ions, and molecular ions will be available as projectiles. Here we present test results for parts of the system. These all indicate that the design criteria will be fulfilled.

Development of internal jet targets for high-luminosity experiments

We report on recent developments of the internal supersonic gas jet target at IUCF. The emphasis has been on hydrogen jets that can be used as targets of ∼ 10 16 atoms/cm 2 thickness in high-luminosity experiments. A method of scanning jets with an ionizing 1 keV electron beam has been employed in order to study jet formation as a function of nozzle geometry and temperature. We summarize our results, obtained by scanning H 2 jets from 23 different nozzles, most of them made from glass capillaries. The present setup of the jet target in the Cooler storage ring is described.

State selective scattering angle dependent capture cross sections measured by cold target recoil ion momentum spectroscopy.

We have developed a new kind of recoil ion momentum spectroscopy technique, using a precooled supersonic gas jet target, to determine state selective, scattering angle dependent cross sections for swift ion-atom collisions ( $0.25,\dots{},1\mathrm{MeV}{\mathrm{He}}^{2+}$ on He), by measuring the transverse and longitudinal momentum of the recoil ion. A longitudinal momentum resolution of $\ifmmode\pm\else\textpm\fi{}0.13\mathrm{a}.\mathrm{u}.$ was achieved, about a factor of 30 better than ever obtained before, which enables a clear separation of K and L shell capture. In the transverse direction a resolution corresponding to a projectile scattering angle uncertainty of $\ensuremath{\Delta}{\ensuremath{\vartheta}}_{P}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}\ifmmode\pm\else\textpm\fi{}1\ensuremath{\mu}\mathrm{rad}$ was obtained.

Three-body final-state momentum distributions for swift H+ and He2+ on He collisions

The transverse and longitudinal momentum distributions of He+ ions produced by 0.25-1 MeV u-1 H+ and He2+ impact have been measured using a precooled supersonic gas jet target (cold-target recoil ion-momentum spectroscopy-COLTRIMS). The transverse momentum of the recoil ions is mainly determined by the impact parameter. In the longitudinal direction the recoil ions are slightly backwardly directed. The width of the longitudinal momentum distribution is close to the electron momentum distribution in the initial state. This distribution gets much broader for larger transverse momentum transfer (i.e. smaller impact parameters). The experimental results are in good agreement with nCTMC calculations.

Nuclear physics experiments with the ornl-hhirf supersonic gas jet target

A study of target-like fragments produced by bombarding a 14N target with 150 MeV 28Si shows that mass and charge distribution of products from orbiting processes is determined by partitioning of an equilibrated dinuclear system. The experiment was performed with the HHIRF supersonic gas jet target which is also described briefly.

The HHIRF supersonic gas jet target facility

We describe a supersonic gas jet target built for studying reactions induced by heavy ions with high energy resolution. The device produces very localized high density gas jets in a near vacuum environment and is presently installed in the scattering chamber of a magnetic spectrograph at the ORNL HHIRF. With a 100 MeV 16O beam collimated to a size of approximately 1 mm2 at the target, image sizes of 0.42 mm have been obtained at the focal plane of the spectrograph with a solid angle of 2.4 msr and target densities of 15–30 μg/cm2.