The reconstruction of extensive air showers (arrival direction, core position and energy estimation) by the surface detector of the Pierre Auger Observatory is discussed together with the corresponding accuracy. We determine the angular reconstruction accuracy as a function of the station multiplicity by using two different aproaches. We discuss statistical and systematic uncertainties in the d...

Ground based Cherenkov γ-ray telescopes are sensitive to unpredictable changes in the atmospheric transparency which are difficult to measure and interpret in the absence of a calibrated beam of high energy γ-rays. We use the detector response to Cherenkov emission from cosmic ray initiated air showers to obtain a relative calibration for data obtained under different instrumental and atmospher...

A simple multiwavelength emission instrument utilizing a commercial grating monochromator, a fiber optic sensor to collect radiation from an acetylene-air flame, and a CCD detector, has been evaluated for pedagogical value in the undergraduate curriculum. Simultaneous determination of Na, Li, K, Rb at ppb level, and Ca, Sr, Ba at ppm level was achieved. The instrument is affordable, yet suitabl...

Phase-measurement interferometry (PM!) techniques enable quantitative measurements to be performed in optical testing, holographic interferometry, and speckle metrology. This paper will present results of error analyses of the most common errors in phase-measurement techniques. These errors include miscalibrated and nonlinear phase shifters, detector nonlinearities, detection quantization, vibr...

Air-ions and radon are two atmospheric trace constituents which have two opposite effects on human health: the ions are beneficial, and radon gas is potentially lethal as it increases the risk of lung cancer. In the lower troposphere, radon is the most important generator of the air-ions. Ionization by cosmic rays and radioactive minerals is almost constant in daily cycles, and variation of air...

A pulsed periodically poled lithium niobate optical parametric oscillator operating in a cavity with a grazing-incidence grating configuration was used for sensitive and precise measurement of trace quantities of methane in nitrogen by photoacoustic spectroscopy with a novel differential photoacoustic detector. A sensitivity of 1.2 parts in 10(9) by volume of methane was obtained in direct cali...

We present measurements of the depth of maximum for extensive air showers (EAS) produced by cosmic ray nuclei with energies above 10eV. The air showers were observed using the University of Utah's Fly's Eye detectors operating in stereo mode. The data show an elongation rate of 69 ± 5 g/ cm per decade above 10eV before correction for triggering and resolution effects. These effects contribute a...

Most naturally occurring radioactive materials contain alpha emitters. They are widespread in air, water and solids, and often of economic importance. Strict radiation protection regulations, as well as scientific curiosity and teaching with experiments call for a mobile and handy instrument with high sensitivity, resolution, and versatility to measure low-level radioactivity. Due to their inhe...

A wide field of view, high duty factor TeV gamma-ray observatory is essential for studying TeV astrophysical sources, because most of these sources are either highly variable or are extended. Milagro is such a TeV detector and has performed the deepest survey of the Northern Hemisphere sky at TeV energies. In addition to detecting the Crab Nebula and Mrk 421, which are known TeV sources, Milagr...

Long-termmeasurements of radon progeny concentrations using Solid-State nuclear tract detector are being actively explored. These measurements depend critically on the thickness of the removed layer during etching. Scanning electron microscope (SEM) observations have identi;ed irregularities in etched LR 115 detectors, such as detachment of the active layer from the substrate and formation of a...