Neutrinos from Cosmic Ray Accelerators in the Cygnus Region of the Galaxy

While supernova remnants have been identified as the most likely sources of the galactic cosmic rays, no conclusive observational evidence for this association exists. We show here that IceCube has the possibility of producing incontrovertible evidence by detecting neutrinos produced by the cosmic ray beam interacting with the hydrogen in the vicinity of the supernova shock expanding into the interstellar medium. We show that the observational information on gamma ray fluxes from the Cygnus region, although limited, is sufficient to pinpoint the expected event rate of the neutrinos associated with a single source of 0.5 Crab at the TeV level to within a factor of two, between 2 and 3.8 neutrinos per year. Finally, we note that recent gamma-ray observations reveal the presence of at least three and possibly up to eight such sources, raising the possibility of seeing more than 10 neutrinos per year from these sources alone.Comment: Latex, 16 pages, uses pdproc.sty (included), 7 postscript figures. Talk presented at the XII International Workshop on Neutrino Telescopes, Istituto Veneto di Scienze, Lettere ed Arti, Venice, Italy, March 6-9, 2007. Version with added text and reference

Prospects for identifying the sources of the Galactic cosmic rays with IceCube

We quantitatively address whether IceCube, a kilometer-scale neutrino detector under construction at the South Pole, can observe neutrinos pointing back at the accelerators of the Galactic cosmic rays. The photon flux from candidate sources identified by the Milagro detector in a survey of the TeV sky is consistent with the flux expected from a typical cosmic-ray generating supernova remnant interacting with the interstellar medium. We show here that IceCube can provide incontrovertible evidence of cosmic-ray acceleration in these sources by detecting neutrinos. We find that the signal is optimally identified by specializing to events with energies above 30 TeV where the atmospheric neutrino background is low. We conclude that evidence for a correlation between the Milagro and IceCube sky maps should be conclusive after several years.Comment: 5 pages, 5 figures; part of the text and some figures have changed, conclusions remain the same; equals journal versio

Ion Temperature and Flow Velocity Measurements on SSX-FRC

An Ion Doppler Spectroscopy (IDS) diagnostic was used to measure the flow velocity\ud and temperature of a plasma created by SSX-FRC. The diagnostic was based on the\ud principles of Doppler spectroscopy, namely, that the wavelength of a moving light\ud source is shifted proportional to its velocity and the width of an emission line varies\ud with temperature. The emission line at 229.7 nm of Carbon III, an impurity ion in\ud the hydrogen plasma, was imaged and its location and width measured. The IDS\ud system being a work in progress, the minimum resolvable linewidth is higher than the\ud linewidth we expect to see based on previous experiments and so detailed temperature\ud and velocity measurements could not be carried out. SSX's PMT's allow detailed\ud time resolution and the plot of temperature variation with time shows that the width\ud of the line peaks between 30 and 50 J1S before it drops to the minimum resolvable\ud width. Considering the basic plasma physics of the system, it is thought that the\ud wide line is due to velocity shear: oppositely directed jets resulting from magnetic\ud reconnect ion create both a red- and a blue-shifted emission line, which overlap and\ud are imaged as a single, very wide, line. A simple analytical model of a fluid system\ud with velocity shear was created to investigate whether or not shear could cause the\ud widening. The lineshapes this model returned were wide and double-peaked due to\ud overlap, supporting the shear hypothesis

Constraints on the ultra-high-energy neutrino flux from Gamma-Ray bursts from a prototype station of the Askaryan radio array

We report on a search for ultra-high-energy (UHE) neutrinos from gamma-ray bursts (GRBs) in the data set collected by the Testbed station of the Askaryan Radio Array (ARA) in 2011 and 2012. From 57 selected GRBs, we observed no events that survive our cuts, which is consistent with 0.12 expected background events. Using NeuCosmA as a numerical GRB reference emission model, we estimate upper limits on the prompt UHE GRB neutrino fluence and quasi-diffuse flux from 107 to 1010 GeV. This is the first limit on the prompt UHE GRB neutrino quasi-diffuse flux above 107 GeV.0SCOPUS: ar.jinfo:eu-repo/semantics/publishe

A bi-directional fixed-latency clock distribution system

The Askar'yan Radio Array (ARA) Collaboration is constructing a giant array of radio-frequency antennas deployed in the ice near the geographic South Pole. This experiment aims at detecting the extremely weak signal of neutrinos with energies in excess of 100 PeV from ultrahigh-energy cosmic ray interactions with the cosmic microwave background radiation. The antennas are located in shallow holes drilled to depths of 200 m and need high fidelity RF signal transmission over extended lengths to the data acquisition logic at the surface. We report on a transmission scheme whereby signals are digitized in the ice and the waveforms are digitally sent via high-speed serial links. Reconstruction algorithms require distribution of a low-jitter clock from the surface down to the digitization boards in the holes with knowledge of the overall time delay between the two clock domains. Previously, we designed a clock synchronization system using electrical signaling over CAT5. This year we have updated our solution to optical fibers using high speed transceiver blocks in Spartan-6 FPGAs. This note describes our improvements on the latter solution: technical details as well as methods of maintaining a fixed phase between two clocks after power cycles and resets. © 2013 Elsevier B.V.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Research of a long distance clock distribution system

Ultrahigh-energy neutrinos with energies in excess of 100 PeV from the GZK effect will be studied using a new detector at the South Pole called the Askaryan Radio Array (ARA). The radiofrequency emission which occurs when these particles interact in the glacial ice is detected by an array of antennas spread out over an enormous area, over 100 km2 and embedded in the ice at depths of 200 m to increase sensitivity. Signals from the antennas are digitized by specialized electronics and must be time synchronized with accuracies of order 50 ps or less for event reconstruction to function properly. A system has been proposed which digitizes the impulse waveforms in situ in the ice and sends the data to the surface using high-speed serial links. This requires distribution of a low-jitter clock to each hole but has substantial advantages in cost and power which drive our development effort to realize this technology. Last year we implemented a first version of a long distance clock synchronization system using electrical signaling over CAT5. This year we have updated our solution to optical fiber using high speed transceiver blocks in Spartan 6 FPGAs. The master clock is embedded into the data stream and distributed to the various holes where a phase-locked derivative is recovered. In this way, we have implemented a 1.25 Gbps data link over a bi-directional communication system fulfilling the requirements of the project. This note describes our efforts on the latter solution: technical details as well as methods of maintaining fixed phase difference between two clocks after power cycle and reset. © 2013 IOP Publishing Ltd and Sissa Medialab srl.SCOPUS: cp.jinfo:eu-repo/semantics/publishe

On the feasibility of RADAR detection of high-energy cosmic neutrinos

We discuss the radar detection technique as a probe for high-energy cosmic neutrino induced particle cascades in a dense medium like ice. With the recent detection of high-energy cosmic neutrinos by the IceCube neutrino observatory the window to neutrino astronomy has been opened. We discuss a new technique to detect cosmic neutrinos at even higher energies than those covered by IceCube, but with an energy threshold below the currently operating Askaryan radio detectors. A calculation for the radar return power, as well as first experimental results will be presented.SCOPUS: cp.pinfo:eu-repo/semantics/publishe