Indication for a volatile element 114 Eichler, Robert; Aksenov, N. V.; Albin, Yu. V. ...
Radiochimica acta,
01/2010, Letnik:
98, Številka:
3
Journal Article
The Majorana Parts Tracking Database Abgrall, N.; Aguayo, E.; Avignone, F.T. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2015, Letnik:
779, Številka:
C
Journal Article
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The Majorana Demonstrator is an ultra-low background physics experiment searching for the neutrinoless double beta decay of 76Ge. The Majorana Parts Tracking Database is used to record the history of ...components used in the construction of the Demonstrator. The tracking implementation takes a novel approach based on the schema-free database technology CouchDB. Transportation, storage, and processes undergone by parts such as machining or cleaning are linked to part records. Tracking parts provide a great logistics benefit and an important quality assurance reference during construction. In addition, the location history of parts provides an estimate of their exposure to cosmic radiation. A web application for data entry and a radiation exposure calculator have been developed as tools for achieving the extreme radio-purity required for this rare decay search.
Flerovium (Fl, element 114) is the heaviest element chemically studied so far. To date, its interaction with gold was investigated in two gas-solid chromatography experiments, which reported two ...different types of interaction, however, each based on the level of a few registered atoms only. Whereas noble-gas-like properties were suggested from the first experiment, the second one pointed at a volatile-metal-like character. Here, we present further experimental data on adsorption studies of Fl on silicon oxide and gold surfaces, accounting for the inhomogeneous nature of the surface, as it was used in the experiment and analyzed as part of the reported studies. We confirm that Fl is highly volatile and the least reactive member of group 14. Our experimental observations suggest that Fl exhibits lower reactivity towards Au than the volatile metal Hg, but higher reactivity than the noble gas Rn.
Currently, gas phase chemistry experiments with heaviest elements are usually performed with the gas-jet technique with the disadvantage that all reaction products are collected in a gas-filled ...thermalisation chamber adjacent to the target. The incorporation of a physical preseparation device between target and collection chamber opens up the perspective to perform new chemical studies. But this approach requires detailed knowledge of the stopping force (STF) of the heaviest elements in various materials. Measurements of the energy loss of mercury (Hg), radon (Rn), and nobelium (No) in Mylar and argon (Ar) were performed at low kinetic energies of around (40–270) keV per nucleon. The experimentally obtained values were compared with STF calculations of the commonly used program for calculating stopping and ranges of ions in matter (SRIM). Using the obtained data points an extrapolation of the STF up to element 114, eka-lead, in the same stopping media was carried out. These estimations were applied to design and to perform a first chemical experiment with a superheavy element behind a physical preseparator using the nuclear fusion reaction
244Pu(
48Ca;
3n)
289114. One decay chain assigned to an atom of
285112, the α-decay product of
289114, was observed.
To characterize the mammographic appearance of invasive lobular carcinoma in a large series of screening-detected consecutive breast cancers and to evaluate the ability of a computer-aided detection ...system to mark these carcinomas.
Investigators used the Breast Imaging Reporting and Data System lexicon to characterize lesions as part of a retrospective review of 90 screening mammographic examinations that led to biopsy-proved diagnosis of 94 invasive lobular carcinoma lesions. The 40 available prior mammographic examinations (obtained 9-24 months earlier) were also reviewed to characterize any visible findings. The results of a computer-aided detection analysis were compared with the images, and the sensitivity of the algorithm was calculated for correct detection of the lesions.
Fifty-six (60%) of 94 lesions manifested as masses, of which 40 (71%) were described as irregular and spiculated; 20 (21%) of 94, as architectural distortions; and the remainder, 18 (20%), as either asymmetric densities or calcifications. On the screening mammograms showing biopsy-proved cancers, the sensitivity of the computer-aided detection system was 86 (91%) of 94 lesions. Thirty-one of the 40 prior mammograms showed retrospectively visible findings, and 24 (77%) of 31 were marked by the computer-aided detection system.
Spiculated masses and architectural distortions are the predominant appearances of invasive lobular carcinoma, and a computer-aided detection system correctly marked a high percentage of invasive lobular carcinoma lesions.
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