The observed properties of stars and especially the neutrino signal of the supernova 1987A provide an upper limit to the axion mass, while the age and expansion rate of the universe provide a lower limit. There remains a “window of opportunity” 10 eV ∼ < ma ∼ < 10 eV, with large uncertainties on either side, where axions could still exist and where they would provide a significant fraction or a...

Hierarchical models of galaxy formation now provide a much closer match to observations than they did a few years ago. The progress has been achieved by adjusting the description of baryonic processes such as star formation and supernova/AGN feedback, while leaving the evolution of the underlying dark matter (DM) halos the same. Being most results very sensitive to the input baryonic physics, t...

The results of a new search for positronium decays into invisible final states are reported. Convincing detection of this decay mode would be a strong evidence for new physics beyond the Standard Model (SM): for example the existence of extra–dimensions, of milli-charged particles, of new light gauge bosons or of mirror particles. Mirror matter could be a relevant dark matter candidate. In this...

During the expected 5+ years of operation, the Spitzer Space Telescope is and will continue to produce outstanding infrared images and spectra, and greatly further scientific understanding of our universe. The Spitzer Space Telescope’s instruments are cryogenically cooled to achieve low dark current and low noise. After the cryogens are exhausted, the Spitzer Space Telescope will only be cooled...

Mirror matter type dark matter can exist on the Earth’s surface, potentially in enhanced concentrations at various anomalous impact sites. Mirror matter fragments can draw in heat from the ordinary matter environment, radiate mirror photons and thereby cool the surrounding ordinary matter. We quantify this effect and suggest that it could be used to help locate mirror matter deposits. This meth...

The RPC detectors in the KL-muon (KLM) subsystem of the Belle detector and their performance are described in this paper. The Belle RPCs are built using glass electrodes. This system has operated stably with very high detection efficiency and low dark current since June 1, 1999. r 2003 Elsevier Science B.V. All rights reserved. PACS: 29.40.Cs; 07.05.Hd

The student-built Agricultural Camera (AgCam) now onboard the International Space Station observes the Earth surface through two linescan cameras with Charge-Coupled Device (CCD) arrays sensitive to visible and near-infrared wavelengths, respectively. The electro-optical components of the AgCam were characterized using precision calibration equipment; a method for modeling and applying these me...

The main results of the quality assurance tests performed on the Resistive Plate Chamber used by the ATLAS experiment at LHC as muon trigger chambers are reported and discussed. These are dark current, gas volume tomography, gas tightness, efficiency, and noise rate.

A measurement System for detecting dark currents, generated by the TESLA cavities is proposed. It is based on the cryogenic current comparator principle and senses dark currents in the nA range. Design issues and the application for the CHECHIA cavity test stand are discussed.

©2002, IS&T—The Society for Imaging Science and Technology initial processing stages, any digital image capture device is an additive color reproduction system because the optoelectronic sensor captures or sums photons. Therefore its raw spectral sensitivities must all be positive.6–8 However, when the raw RGB space is electronically varied, the resulting spectral sensitivities may have negativ...