P-terphenyl (PT) and tetraphenyl-butadiene (TPB) have been investigated as possible wavelength shifting materials for use in Ring Imaging Cherenkov (RICH) detectors. Wavelength shifting films made out of these organic molecules absorb light in the UV region and re-emit fluorescence photons at larger wavelength. Used on top of photomultiplier tubes (PMT), they therefore can enhance the quantum e...

KM3NeT (km3 Neutrino Telescope) is planned to be a deep-sea multidisciplinary observatory in the Mediterranean Sea that will provide innovative science opportunities spanning Astroparticle Physics and Earth and Sea Science. KM3NeT will consist of several hundreds of vertical structures, which carry photo-sensors and devices for calibration and environmental measurements. The photo-sensor unit i...

Abnormally high energy events were seen in the Hadronic Forward (HF) calorimeter for pion and muon data during testbeam in 2004. Analysis of testbeam data suggested that such events were caused by particles traveling the entire length of HF and striking the photomultiplier (PMT) windows in the readout box behind HF. Charged particles traversing the window of the PMT emit Cerenkov radiation, whi...

A portion of the Fly's Eye II has been recording Cherenkov flashes since November, 1987, in a declination band which includes these three x-ray sources. The data have been analyzed on a nightly basis in a search for evidence of ultra-high energy (UHE) gamma ray emissions. Introduction. Cyg X-3, Her X-1, and the Crab nebula or pulsar have all been reported to be sources of UHE ã-rays. Reviews on...

Partial discharge (PD) measurement of an insulation system is widely used as a diagnostic tool for the quality control high voltage apparatuses. In ac, conventional method PD detection well established. However, under square voltages such those generated across power electronic converters, cannot discriminate between PDs and switching transients. this context, paper demonstrates fast-rising by ...

For the purpose of direct dark matter detection experiments, highly sensitive photodetectors are needed. The UCLA dark matter team is testing and developing a novel hybrid photodector called Silicon Geiger Hybrid Tube (SiGHT) that can potentially replace the currently used photomultiplier tube. The main component of SiGHT is the silicon photomultiplier. The characterization of the SiPM is being...

The properties of an electron beam trapped and accelerated in a laser wake"eld have been investigated. Plastic scintillating "bers were employed together with position sensitive photomultiplier tubes (PMT) and a series of dipole electro-magnets to study the beam. The measured momentum spectrum peaks around 7 MeV/c with an exponential fall-o! at high momenta up to (70.3$ 19.9) MeV/c. The number ...

In this lab, we investigated the responsivity, time response, and noise performance of various photodetectors, including thermal detectors, silicon photodiodes, and photomultiplier tubes (PMT). A standard helium-neon gas laser (HeNe), operated in the red (632.8 nm), was used as the light source for the measurements of the silicon photodiodes. A flashlight served as a radiation source to measure...

The Hadronic Forward calorimeters of the CMS experiment are Cherenkov calorimeters that use quartz fibers and 1728 photomultiplier tubes (PMTs) for readout. The CMS detector upgrade project requires the current Hamamatsu R7525 PMTs to be replaced with 4-anode, high quantum efficiency R7600-M4 PMTs. The new PMTs will improve the detector resolution, as well as the capability of removing fake eve...