Search results for "Penn"
showing 10 items of 568 documents
Precision mass measurements of antiprotons in a Penning trap
1992
Utilizing electron cooling, the TRAP collaboration has lowered the energy at which antiprotons can be stored and studied by more than 10 orders of magnitude, starting with 6 MeV particles from LEAR. We have held cryogenic antiprotons a few degrees above absolute zero for two months and the storage lifetime so established, more than 3.4 months is the longest directly measured limit for antiprotons. Measuring their cyclotron frequencies in a precision cylindrical Penning trap, we have shown that the inertial masses of the antiprotons and protons are the same to a fractional accuracy of 4 parts in 108, a 1000-fold improvement over the previous comparisons. This is the most stringent test of CP…
The interconversion of the radial motional modes of an ion in a Penning trap mass spectrometer by 4n-polar external radio frequency fields (n= 1,2,3,…
2013
In Penning trap mass spectrometry ion masses are determined by measuring the free cyclotron frequency via the resonant conversion of the magnetron into the cyclotron motional mode, induced by the interaction with an external radio-frequency field. With octupolar rf-fields of frequency the mass resolution has been improved by more than an order of magnitude as compared to conventional quadrupolar fields of frequency and with the same pulse duration. This result raises the question what one might expect from using 12-polar rf-fields with frequency or even 16-polar rf-fields with frequency . In this paper the theoretical model for the interconversion of the radial modes by quadrupolar and octu…
Measurement of fission yields and isomeric yield ratios at IGISOL
2018
Data on fission yields and isomeric yield ratios (IYR) are tools to study the fission process, in particular the generation of angular momentum. We use the IGISOL facility with the Penning trap JYFLTRAP in Jyväskylä, Finland, for such measurements on 232Th and natU targets. Previously published fission yield data from IGISOL concern the 232Th(p,f) and 238U(p,f) reactions at 25 and 50 MeV. Recently, a neutron source, using the Be(p,n) reaction, has been developed, installed and tested. We summarize the results for (p,f) focusing on the first measurement of IYR by direct ion counting. We also present first results for IYR and relative yields for Sn and Sb isotopes in the 128-133 mass range fr…
ATRAP antihydrogen experiments
2007
Antihydrogen (Hbar) was first produced at CERN in 1996. Over the past decade our ATRAP collaboration has made massive progress toward our goal of producing large numbers of cold Hbar atoms that will be captured in a magnetic gradient trap for precise comparison between the atomic spectra of matter and antimatter. The AD at CERN provides bunches of 3 × 107 low energy Pbars every 100 seconds. We capture and cool to 4 K, 0.1% of these in a cryogenic Penning trap. By stacking many bunches we are able to do experiments with 3 × 105 Pbars. ∼100 e+/sec from a 22Na radioactive source are captured and cooled in the trap, with 5 × 106 available experiments.We have developed 2 ways to make Hbar from t…
First Capture of Antiprotons in a Penning Trap: A Kiloelectronvolt Source
1986
Antiprotons from the Low Energy Antiproton Ring of CERN are slowed from 21 MeV to below 3 keV by being passed through 3 mm of material, mostly Be. While still in flight, the kiloelectronvolt antiprotons are captured in a Penning trap created by the sudden application of a 3-kV potential. Antiprotons are held for 100 s and more. Prospects are now excellent for much longer trapping times under better vacuum conditions. This demonstrates the feasibility of a greatly improved measurement of the inertial mass of the antiproton and opens the way to other intriguing experiments.
The Mainz Cluster Trap
1999
When cluster ions are stored by electromagnetic forces they are available in the gas phase for extended preparations and investigations. Over the last decade a Penning trap (Ion Cyclotron Resonance) apparatus has been constructed and further developed with respect to metal cluster research at the Institute of Physics at Mainz. It allows to capture and accumulate ion bunches injected from an external cluster source and to manipulate the ions’ motion, i.e. select and center the clusters of interest. The interactions that have been investigated include those with inert and chemically reactive gases, photons and electrons. Multiple mass spectrometric steps such as fragment ion selection can be …
Observation of electronic and geometric shell structures of small silver clusters
1999
Singly charged silver clusters Open image in new window in the size range n = 17 to n = 78 have been captured and stored in a Penning trap, size selected and subjected to an electron beam which leads to further ionization as well as dissociation. The resulting abundance spectra of doubly and triply charged clusters show several features: (1) A critical size for the production of doubly charged clusters which can be understood in terms of the decay pathways as previously investigated by collision induced dissociation, (2) an odd-even alternation in the abundance of singly and doubly charged clusters which inverses sign with change of charge state, (3) prominent signals for particular doubly …
Mass spectrometry of atomic ions produced by in-trap decay of short-lived nuclides
2005
The triple-trap mass spectrometer ISOLTRAP at ISOLDE/CERN has demonstrated the feasibility of mass spectrometry of in-trap-decay product ions. This novel technique gives access to radionuclides, which are not produced directly at ISOL-type radioactive ion beam facilities. As a proof of principle, the in-trap decay of $^{37}K^+$ has been investigated in a Penning trap filled with helium buffer gas. The half-life of the mother nuclide was confirmed and the recoiling $^{37}Ar^+$ daughter ion was contained within the trap. The ions of either the mother or the daughter nuclide were transferred to a precision Penning trap, where their mass was determined.
Position-sensitive ion detection in precision Penning trap mass spectrometry
2009
A commercial, position-sensitive ion detector was used for the first time for the time-of-flight ion-cyclotron resonance detection technique in Penning trap mass spectrometry. In this work, the characteristics of the detector and its implementation in a Penning trap mass spectrometer will be presented. In addition, simulations and experimental studies concerning the observation of ions ejected from a Penning trap are described. This will allow for a precise monitoring of the state of ion motion in the trap.
First β -decay scheme of Nb107 : New insight into the low-energy levels of Mo107
2019
Monoisotopic samples of $^{107}\mathrm{Nb}$ nuclei, produced in the proton-induced fission of $^{238}\mathrm{U}$ and separated using the IGISOL mass separator coupled to a Penning trap, were used to perform $\ensuremath{\beta}$- and $\ensuremath{\gamma}$-coincidence spectroscopy of $^{107}\mathrm{Mo}$. Gamma transitions and excited levels in $^{107}\mathrm{Mo}$ were observed in $\ensuremath{\beta}$ decay for the first time. Spin and parity $1/{2}^{+}$ for the ground state of $^{107}\mathrm{Mo}$ is proposed, to replace the previous $5/{2}^{+}$ assignment. The experimental $\ensuremath{\beta}$-decay half-life of $^{107}\mathrm{Nb}$ was estimated to be $0.27\ifmmode\pm\else\textpm\fi{}0.02$ s.