9 research outputs found
Determination of luminosity for in-ring reactions:A new approach for the low-energy domain
Luminosity is a measure of the colliding frequency between beam and target
and it is a crucial parameter for the measurement of absolute values, such as
reaction cross sections. In this paper, we make use of experimental data from
the ESR storage ring to demonstrate that the luminosity can be precisely
determined by modelling the measured Rutherford scattering distribution. The
obtained results are in good agreement with an independent measurement based on
the x-ray normalization method. Our new method provides an alternative way to
precisely measure the luminosity in low-energy stored-beam configurations. This
can be of great value in particular in dedicated low-energy storage rings where
established methods are difficult or impossible to apply.Comment: 8 pages, 5 figure
New test of modulated electron capture decay of hydrogen-like 142Pm ions: Precision measurement of purely exponential decay
An experiment addressing electron capture (EC) decay of hydrogen-like 142Pm60+ions has been conducted at the experimental storage ring (ESR) at GSI. The decay appears to be purely exponential and no modulations were observed. Decay times for about 9000 individual EC decays have been measured by applying the single-ion decay spectroscopy method. Both visually and automatically analysed data can be described by a single exponential decay with decay constants of 0.0126(7)sâ1for automatic analysis and 0.0141(7)sâ1for manual analysis. If a modulation superimposed on the exponential decay curve is assumed, the best fit gives a modulation amplitude of merely 0.019(15), which is compatible with zero and by 4.9 standard deviations smaller than in the original observation which had an amplitude of 0.23(4)
Electron capture of in collisions with molecules in the energy range between 5.5 and 30.9 MeV/u
The electron-capture process was studied for Xe54+ colliding with H2 molecules at the internal gas target of the Experimental Storage Ring (ESR) at GSI, Darmstadt. Cross-section values for electron capture into excited projectile states were deduced from the observed emission cross section of Lyman radiation, being emitted by the hydrogenlike ions subsequent to the capture of a target electron. The ion beam energy range was varied between 5.5 and 30.9 MeV/u by applying the deceleration mode of the ESR. Thus, electron-capture data were recorded at the intermediate and, in particular, the low-collision-energy regime, well below the beam energy necessary to produce bare xenon ions. The obtained data are found to be in reasonable qualitative agreement with theoretical approaches, while a commonly applied empirical formula significantly overestimates the experimental findings