John N. S. Matthews

The atmospheric transparency measured with a LIDAR system at the Telescope Array experiment

An atmospheric transparency was measured using a LIDAR with a pulsed UV laser (355 nm) at the observation site of Telescope Array in Utah, USA. The measurement at night for two years in 2007–2009 revealed that the extinction coefficient by aerosol at the ground level is 0.033−0.012+0.016km−1 and the vertical aerosol optical depth at 5 km above the ground is 0.035−0.013+0.019. A model of the altitudinal aerosol distribution was built based on these measurements for the analysis of atmospheric attenuation of the fluorescence light generated by ultra high energy cosmic rays.

Calibration of photomultiplier tubes for the fluorescence detector of telescope array experiment using a Rayleigh scattered laser beam

Abstract We performed photometric calibration of the PhotoMultiplier Tube (PMT) and readout electronics used for the new fluorescence detectors of the Telescope Array (TA) experiment using Rayleigh scattered photons from a pulsed nitrogen laser beam. The experimental setup, measurement procedure, and results of calibration are described. The total systematic uncertainty of the calibration is estimated to be 7.2%. An additional uncertainty of 3.7% is introduced by the transport of the calibrated PMTs from the laboratory to the TA experimental site.

Steerable laser system for UV atmospheric monitoring at the High-Resolution Fly's Eye

Monitoring the aerosol component of the lowest 10 km of the atmosphere at UV wavelengths (300 - 400 nm) is an important part of the High Resolution Flys Eye astrophysics experiment. Our method of atmospheric monitoring uses a frequency tripled YAG laser and a steering system that can point the beam anywhere in the sky. The same detector that measures scintillation light from high energy cosmic rays also measures light scattered from this laser system over a range of laser energies, geometries, and polarizations. This paper describes the technique, the laser system, and some recent measurements.

POEMMA: Probe Of Extreme Multi-Messenger Astrophysics

The Probe Of Extreme Multi-Messenger Astrophysics (POEMMA) mission is being designed to establish charged-particle astronomy with ultra-high energy cosmic rays (UHECRs) and to observe cosmogenic tau neutrinos (CTNs). The study of UHECRs and CTNs from space will yield orders-of-magnitude increase in statistics of observed UHECRs at the highest energies, and the observation of the cosmogenic flux of neutrinos for a range of UHECR models. These observations should solve the long-standing puzzle of the origin of the highest energy particles ever observed, providing a new window onto the most energetic environments and events in the Universe, while studying particle interactions well beyond accelerator energies. The discovery of CTNs will help solve the puzzle of the origin of UHECRs and begin a new field of Astroparticle Physics with the study of neutrino properties at ultra-high energies.

Measurement of the branching ratio of K(L) ---> e+ e- gamma gamma

A new measurement of the [ital K][sub [ital L]][r arrow][ital e][sup +][ital e][sup [minus]][gamma][gamma] branching ratio was carried out in Fermilab experiment E799. We observed 58 [ital K][sub [ital L]][r arrow][ital e][sup +][ital e][sup [minus]][gamma][gamma] events. The measured branching ratio is [ital B]([ital K][sub [ital L]][r arrow][ital e][sup +][ital e][sup [minus]][gamma][gamma], [ital E][sub [gamma]][sup *][gt]5 MeV) = [6.5[plus minus]1.2 (stat) [plus minus]0.6 (syst)] [times]10[sup [minus]7].

Probing the radar scattering cross-section for high-energy particle cascades in ice

Recently the radar scattering technique to probe neutrino induced particle cascades above PeV energies in ice was investigated. The feasibility of the radar detection method was shown to crucially depend on several up to now unknown plasma properties, such as the plasma lifetime and the free charge collision rate. To determine these parameters, a radar scattering experiment was performed at the Telescope Array Electron Light Source facility, where a beam of high-energy electrons was directed in a block of ice. The induced ionization plasma was consequently probed using a radar detection set-up detecting over a wide frequency range from 200 MHz up to 2 GHz. First qualitative results of this experiment will be presented.

The instruments of sFLASH experiment

We will report on the setup and calibration of the instrumentation for sFLASH. The sFLASH experiment is a measurement of the air fluorescence from ∼10

Coherent radio emission from the electron beam sudden appearance

^{21}

The Prototype Opto-mechanical System for the Fluorescence detector Array of Single-pixel Telescopes

eV artificial air showers developed in an alumina target by an electron beam provided from End Station A of the Stanford Linear Accelerator Center (SLAC). sFLASH employs Photomultiplier tubes (PMTs) to detect the fluorescence photons and an Integrating Charge Transformer (ICT) to measure the beam current. The PMTs are positioned ~10m perpendicular to shower axis are used to measure the air fluorescence photons. The absolute gain of the PMTs was measured using CRAYS at the Institute of Cosmic-Ray Research, Japan. CRAYS is a PMT photo-gain calibration system consisting of a vessel containing nitrogen gas and a 14μJ nitrogen (337.1 nm) laser. The gain of each PMT was monitored during the course of the experiment using a YAP pulser (YAlO: Ce +

First results from the full-scale prototype for the Fluorescence detector Array of Single-pixel Telescopes

^{241}