DURING THE MONTH of June, 1955, while measurements were being made of the depth of penetration of moonlight into the sea off the Kona Coast (S. W. coast) of the island of Oahu in the Hawaiian gtoup, some information was obtained on bioluminescence in deep water in this region and on the effect of moonlight on the vertical distribution of luminescent organisms. Observations of bioluminescence we...

VERITAS employs a 12m segmented mirror and pixellated photomultiplier tube camera to detect the brief pulse of Cherenkov radiation produced by the extensive air shower initiated by a cosmic high-energy gamma ray. The VERITAS data acquisition system consists of a 500 Mega-Sample-PerSecond custom-built flash ADC system, which samples the Cherenkov light pulse every 2 nanoseconds. The integrated c...

AMIGA (Auger Muons and Infill for the Ground Array) is an upgrade of the Pierre Auger Observatory designed to extend its energy range of detection and to directly measure the muon content of the cosmic ray primary particle showers. The array will be formed by an infill of surface water-Cherenkov detectors associated with buried scintillation counters employed for muon counting. Each counter is ...

AMIGA (Auger Muons and Infill for the Ground Array) is an upgrade of the Pierre Auger Observatory designed to extend its energy range of detection and to directly measure the muon content of the cosmic ray primary particle showers. The array will be formed by an infill of surface water-Cherenkov detectors associated with buried scintillation counters employed for muon counting. Each counter is ...

AMIGA (Auger Muons and Infill for the Ground Array) is an upgrade of the Pierre Auger Observatory designed to extend its energy range of detection and to directly measure the muon content of the cosmic ray primary particle showers. The array will be formed by an infill of surface water-Cherenkov detectors associated with buried scintillation counters employed for muon counting. Each counter is ...

We have developed a new photomultiplier tube (PMT) with high sensitivity for a wavelength-shifter fiber readout of plastic scintillators. Improvements of the photoelectron yield were made on a 2-in. PMT (Hamamatsu R329) by adopting (1) a prism-shaped photocathode, (2) an extended-green photocathode material, and (3) an optical mirror surface of the electrodes. As a result, the number of photoel...