Production and ionization of neutron-rich nuclides
The Research Reactor TRIGA Mainz
The Mainz TRIGA (Training Research Isotope General Atomics) reactor can be operated in a steady-state mode with a maximum power of 100 kWtherm or in the pulsed mode with 30 ms pulse duration (FWHM) at a peak power of 250 MWtherm. Four horizontal beam tubes give access to the strongest neutron flux near the reactor core (1.8x1011 cm-2s-1) . Here, a gas-jet system is used for continuous transport of fission products from a fissionable target (U-235, Pu-239 or Cf-249) mounted close to the reactor core, through the biological shield to an ion source on a HV platform.
Gas-jet transport of the fission products
TRIGA-Trap uses an aerosol loaded gas-jet system for fission product transport, see Fig. 2. The fission products are collimated in an aerodynamical lens, ionized in a high-temperature surface ion source, accelerated, mass separated by a 90 deg. dipole magnet, cooled and bunched in a gas-filled radio-frequency quadrupole structure, decelerated in a pulsed drift-tube and transported towards the Penning-trap mass spectrometer .
High temperature surface ion source
Currently a high temperature surface ion source  is available which in connection with a gas jet transport system enables access to certain fission products. For this purpose a 30 kV HV platform has been installed. The cathode is a tantalum ionizer cylinder heated indirectly by electron bombardment from two hot filaments.
The ionizer can be heated rapidly to any temperature up to 2500 °C. The chosen temperature can be kept constant with only minor fluctuations in the range of 4 °C in 24 h. The components of the ion source are long-term stable, thus it can be operated without maintenance for two or more weeks.
The mass separator is a 90 deg dipole magnet with a bending radius of 0.5 m and a mass resolution of about 300. The PC controlled DANFYSIK power supply is capable of 250 A current with a stability of 10 ppm, resulting in a B-field intensity of 1.1 T. A stepper motor driven split-pair system is fitted behind the magnet.
Cooler and Buncher
COLETTE (Cooler for Emittance Elimination) is a segmented, radiofrequency quadrupole, which was designed for cooling continuous radioactive beams for injection into the MISTRAL spectrometer at CERN-ISOLDE . The device has been transferred to TRIGA-Trap and it is integrated in the beam-line . COLETTE transforms the continuous 30 keV beam into bunches, and cools the confined ion ensemble by buffer-gas to reduce the phase space volume.
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