[Show abstract][Hide abstract] ABSTRACT: We report on the realization and operation of a fast ion beam trap of the linear electrostatic type employing liquid helium cooling to reach extremely low blackbody radiation temperature and residual gas density and, hence, long storage times of more than 5 min which are unprecedented for keV ion beams. Inside a beam pipe that can be cooled to temperatures <15 K, with 1.8 K reached in some locations, an ion beam pulse can be stored at kinetic energies of 2-20 keV between two electrostatic mirrors. Along with an overview of the cryogenic trap design, we present a measurement of the residual gas density inside the trap resulting in only 2 x 10(3) cm(-3), which for a room temperature environment corresponds to a pressure in the 10(-14) mbar range. The device, called the cryogenic trap for fast ion beams, is now being used to investigate molecules and clusters at low temperatures, but has also served as a design prototype for the cryogenic heavy-ion storage ring currently under construction at the Max-Planck Institute for Nuclear Physics.
Full-text · Article · May 2010 · The Review of scientific instruments
[Show abstract][Hide abstract] ABSTRACT: A cryogenic electrostatic storage ring (CSR) is under construction at the Max-Planck-Institut für Kernphysik Heidelberg, which will be a unique facility for low velocity phase space cooled ion beams. Among other experiments the storage and cooling of molecular ions in their rotational ground state is planned. To meet this requirement the ring must provide a vacuum with a residual gas density below 10000 molecules/cm3, which will be achieved by cooling the vacuum chamber to 2-10 K. The projected stored beam current will be in the range of 1 nA - 1 μA. The resulting low signal strengths of the beam position pick-ups, current monitors and the Schottky monitor put strong demands on these diagnostics tools. The very low residual gas density of the CSR does not allow using a conventional residual gas monitor to measure the profile of the stored ion beam. Thus, other methods were investigated. An overview of the CSR diagnostics tools and procedures will be given.