arXiv subjects

H. G. Essel

Publications and source records attributed to H. G. Essel.

4 recordsLinked to original sources

arXiv2019

New Test of Modulated Electron Capture Decay of Hydrogen-Like $^{142}$Pm Ions: Precision Measurement of Purely Exponential Decay

An experiment addressing electron capture (EC) decay of hydrogen-like $^{142}$Pm$^{60+}$ 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) s$^{-1}$ for automatic analysis and 0.0141(7) s$^{-1}$ for 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).

nucl-ex↗

arXiv2008

Comment on the paper "Search for oscillation of the electron-capture decay probability of $^{142}$Pm" at arXiv:0807.0649v1

It is argued that orbital electron-capture decays of neutral $^{142}$Pm atoms implanted into the lattice of a solid (LBNL experiment) do not fulfil the constraints of true two-body beta decays, since momentum as well as energy of the final state are distributed among three objects, namely the electron neutrino, the recoiling daughter atom and the lattice phonons. To our understanding, this could be a reason for the non-observation of a periodic time modulation in the number of electron-capture decays of implanted neutral $^{142}$Pm atoms.

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arXiv2008

Observation of Non-Exponential Orbital Electron Capture Decays of Hydrogen-Like $^{140}$Pr and $^{142}$Pm Ions

We report on time-modulated two-body weak decays observed in the orbital electron capture of hydrogen-like $^{140}$Pr$^{59+}$ and $^{142}$Pm$^{60+}$ ions coasting in an ion storage ring. Using non-destructive single ion, time-resolved Schottky mass spectrometry we found that the expected exponential decay is modulated in time with a modulation period of about 7 seconds for both systems. Tentatively this observation is attributed to the coherent superposition of finite mass eigenstates of the electron neutrinos from the weak decay into a two-body final state.

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arXiv2003

Go4 v2 Analysis Framework

Go4 developed at GSI is an analysis framework with a general purpose non blocking GUI. Go4 is based on ROOT. The GUI is implemented in Qt using GSI's QtROOT interface. Analysis and GUI run in separate tasks communicating through asynchronous object channels. A Go4 analysis may use any ROOT features. It can be organized in steps, which can be controlled from the GUI according to the user specifications. Each step is composed of event objects, the event processing, and event IO. Go4 composite event classes allow the construction of arbitrary complex events hierarchically composed of objects. The IO of the composite event objects to and from ROOT trees/branches is provided without explicit programming. The Go4 tree viewer can browse arbitrary hierarchy levels of composite events. The GUI provides hooks to attach user written GUIs. These GUIs have access to all objects of the analysis, i.e. events for asynchronous event display. Using the Qt designer the development of such GUIs is very efficient. The Go4 fit package (API and GUI) is a powerful and extendable tool to model and fit experimental data. The Go4 framework is especially useful for on-line monitoring. The HADES experiment at GSI integrated the existing ROOT based analysis into Go4 and is using it on-line with dedicated GUIs.

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