M. Sewtz

The SHIPTRAP project: A capture and storage facility at GSI for heavy radionuclides from SHIP

SHIPTRAP is an ion trap facility which is being set up to deliver very clean and cool beams of singly-charged recoil ions produced at the SHIP velocity filter at GSI Darmstadt. SHIPTRAP consists of a gas cell for stopping and thermalizing high-energy recoil ions from SHIP, a rf ion guide for extraction of the ions from the gas cell, a linear rf trap for accumulation and bunching of the ions, and a Penning trap for isobaric purification. The physics programme of the SHIPTRAP facility comprises mass spectrometry, nuclear spectroscopy, laser spectroscopy and chemistry of transeinsteinium elements.

A COMPACT APPARATUS FOR MASS SELECTIVE RESONANCE IONIZATION SPECTROSCOPY IN A BUFFER GAS CELL

Abstract An ultra-sensitive laser spectroscopic method for the investigation of transuranium nuclides has been developed based on resonance ionization in an argon buffer gas cell. This method has been combined with ion-guide extraction and mass selective direct detection of the resonantly ionized atoms. Using argon as a buffer gas, recoils of fusion reactions can be thermalized even at low pressure. The differential pumping system consists of only one roots pump and two turbo molecular pumps. The set-up has been tested with 243 Am evaporated from a filament located inside the optical gas cell. Resonance ionization is performed using a two-step excitation with an excimer-dye-laser combination. The ions are transported by a suitable electrical field to the nozzle, and are ejected with the ion-guide gas jet into an electrostatic lens system followed by a quadrupole mass spectrometer and a channeltron detector. The total sensitivity has been measured to be 1.0 × 10 −4 . The extraction time for ions based on electric field guidance amounts to 1.5 ms, which is two orders of magnitude faster than the ion-guide gas exchange time of this set-up.

Resonance ionization spectroscopy of fermium (Z=100)☆☆☆

Laser spectroscopy has been applied for the first time to measure resonant transition frequencies of fermium (Zs 100). A number of 2.7=10 atoms was electrodeposited on a Ta filament and covered with a 1 mm Ti layer. Fm 10

Isotope shift measurement at 244fAm

AbstractOptical isotope shift measurements have been performed at the 244fAm fission isomers (T1/2=1 ms) with low target production rates of 10/s employing resonance ionization spectroscopy in a buffer gas cell. The isotope shift ratio IS244f,241/IS243,241 = 42.0(9) has been measured at the 500.02 nm transition. A change in the nuclear mean charge radius

Status of the SHIPTRAP Project: A Capture and Storage Facility for Heavy Radionuclides from SHIP

\delta \langle r^2 \rangle _{{\text{opt}}}^{{\text{224}}f,241}

First observation of atomic levels for the element fermium (Z=100).

= 5.41(31) fm2 and an intrinsic quadrupole moment

Laser Spectroscopic Investigation of the Element Fermium (Z = 100)

Q_{{\text{20}}}^{{\text{224}}f}