42 research outputs found
Measurement of the gamma ray background in the Davis Cavern at the Sanford Underground Research Facility
Deep underground environments are ideal for low background searches due to the attenuation of cosmic rays by passage through the earth. However, they are affected by backgrounds from Ī³-rays emitted by 40K and the 238U and 232Th decay chains in the surrounding rock. The LUX-ZEPLIN (LZ) experiment will search for dark matter particle interactions with a liquid xenon TPC located within the Davis campus at the Sanford Underground Research Facility, Lead, South Dakota, at the 4,850-foot level. In order to characterise the cavern background, in-situ Ī³-ray measurements were taken with a sodium iodide detector in various locations and with lead shielding. The integral count rates (0--3300~keV) varied from 596~Hz to 1355~Hz for unshielded measurements, corresponding to a total flux in the cavern of 1.9Ā±0.4~Ī³ cmā2sā1. The resulting activity in the walls of the cavern can be characterised as 220Ā±60~Bq/kg of 40K, 29Ā±15~Bq/kg of 238U, and 13Ā±3~Bq/kg of 232Th
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A combined cosmic ray muon spectrometer and high energy air shower array
Cosmic rays have been detected at energies in excess of 10/sup 20/ eV, and individual sources have been conclusively identified as intense emitters of gamma rays at energies up to 10/sup 16/ eV. There is clearly a great deal of exciting astrophysics to be learned from such studies, but it has been suggested that there may be particle physics to be learned from the cosmic beam as well. Based in particular on the reports of surprisingly high fluxes of underground muons from the direction of Cygnus X-3 modulated by the known orbital period, there have been several suggestions recently invoking stable supersymmetric particles produced at Cygnus X-3, enhanced muon production from high energy photons, quark matter, and ''cygnets.'' Although the underground muon results have been questioned, it may still be worthwhile to consider the possibility of new physics beyond the standard model with energy scale (G/sub F/)/sup -1/2/ greater than or equal to 0.25 TeV. For example, there have been recent discussions on the experimental signatures to be observed from new high energy photon couplings to matter, exchanges between constituent quarks and leptons, and stable gluinos and photinos mixed in with the cosmic gamma ray flux. We describe here a possible detector to search for such effects. We utilize the possibility that point sources like Cygnus X-3 can be used to provide a directional time-modulated ''tagged'' high energy photon beam
Lethal effects of high temperatures on nondiapausing pupae ofBathyplectes curculionis [Hym.: Ichneumonidae]
The effects of coal ash basin effluent and thermal loading on bacterial populations of flowing streams
Philosophical conceptions of information
āThe original publication is available at www.springerlink.comā Copyright Springer'I love information upon all subjects that come in my way, and especially upon those that are most important.' Thus boldly declares Euphranor, one of the defenders of Christian faith in Berkleyās Alciphron (Berkeley, (1732), Dialogue 1, Section 5, Paragraph 6/10). Evidently, information has been an object of philosophical desire for some time, well before the computer revolution, Internet or the dot.com pandemonium (see for example Dunn (2001) and Adams (2003)). Yet what does Euphranor love, exactly? What is information? The question has received many answers in different fields. Unsurprisingly, several surveys do not even converge on a single, unified definition of information (see for example Braman 1989, Losee (1997), Machlup and Mansfield (1983), Debons and Cameron (1975), Larson and Debons (1983)).Peer reviewe