ISR@bucknell

isr@bucknell was a newsletter published by Bucknell University\u27s Information Services and Resources department (later Library and Information Technology). The publication served the community by providing software, project, and service updates. Regular features included a letter from the Associate Vice President for Information Services and Resources, the Ask ISR column, and featured ISR web pages. This issue includes the following articles: The ASK desk always at your service, ISR: on target, The new ISR web pages, ResNet in full swing, Windows NT teaching labs, and Ask ISR

Tunable complex-valued multi-tap microwave photonic filter based on single silicon-oninsulator microring resonator

This paper was published in OPTICS EXPRESS and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/10.1364/OE.19.012402. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under lawA complex-valued multi-tap tunable microwave photonic filter based on single silicon-on-insulator microring resonator is presented. The degree of tunability of the approach involving two, three and four taps is theoretical and experimentally characterized, respectively. The constraints of exploiting the optical phase transfer function of a microring resonator aiming at implementing complex-valued multi-tap filtering schemes are also reported. The trade-off between the degree of tunability without changing the free spectral range and the number of taps is studied in-depth. Different window based scenarios are evaluated for improving the filter performance in terms of the side-lobe level. (C) 2011 Optical Society of AmericaThe authors wish to acknowledge the technical support given by Prof. Pascual Munoz and David Domenech, as well as the financial support of the European Commission Seventh Framework Programme (FP 7) project GOSPEL; the Generalitat Valenciana through the Microwave Photonics research Excellency award programme GVA PROMETEO 2008/092 and also the Plan Nacional I + D TEC2007-68065-C03-01 and TEC2008-06145.Lloret Soler, JA.; Sancho Durá, J.; Pu, M.; Gasulla Mestre, I.; Yvind, K.; Sales Maicas, S.; Capmany Francoy, J. (2011). Tunable complex-valued multi-tap microwave photonic filter based on single silicon-on-insulator microring resonator. Optics Express. 19(13):12402-12407. https://doi.org/10.1364/OE.19.012402S1240212407191

Rocket experiments for spectral estimation of electron density fine structure in the auroral and equatorial ionosphere and preliminary results

Sounding rockets equipped to monitor electron density and its fine structure were launched into the auroral and equatorial ionosphere in 1980 and 1983, respectively. The measurement electronics are based on the Langmuir probe and are described in detail. An approach to the spectral analysis of the density irregularities is addressed and a software algorithm implementing the approach is given. Preliminary results of the analysis are presented

Optical Supersymmetry in the Time Domain

Originally emerged within the context of string and quantum field theory, and later fruitfully extrapolated to photonics, the algebraic transformations of quantum-mechanical supersymmetry were conceived in the space realm. Here, we introduce a paradigm shift, demonstrating that Maxwell's equations also possess an underlying supersymmetry in the time domain. As a result, we obtain a simple analytic relation between the scattering coefficients of a large variety of time-varying optical systems and uncover a wide new class of reflectionless, three dimensional, all-dielectric, isotropic, omnidirectional, polarization-independent, non-complex media. Temporal supersymmetry is also shown to arise in dispersive media supporting temporal bound states, which allows engineering their momentum spectra and dispersive properties. These unprecedented features define a promising design platform for free-space and integrated photonics, enabling the creation of a number of novel reconfigurable reflectionless devices, such as frequency-selective, polarization-independent and omnidirectional invisible materials, compact frequency-independent phase shifters, broadband isolators, and versatile pulse-shape transformers

Search for gravitational wave bursts in LIGO's third science run

We report on a search for gravitational wave bursts in data from the three LIGO interferometric detectors during their third science run. The search targets subsecond bursts in the frequency range 100-1100 Hz for which no waveform model is assumed, and has a sensitivity in terms of the root-sum-square (rss) strain amplitude of hrss ~ 10^{-20} / sqrt(Hz). No gravitational wave signals were detected in the 8 days of analyzed data.Comment: 12 pages, 6 figures. Amaldi-6 conference proceedings to be published in Classical and Quantum Gravit

FIRST DETECTION OF COHERENT ELASTIC NEUTRINO-NUCLEUS SCATTERING ON AN ARGON TARGET

Thesis (Ph.D.) - Indiana University, Department of Physics, 2020Coherent elastic neutrino-nucleus scattering (CEvNS) was first proposed in 1974 but eluded detection for 40 years. The COHERENT collaboration made the first observation of CEvNS at the Oak Ridge National Laboratory Spallation Neutron Source (SNS) with a 14.6 kg CsI[Na] detector. One of the physics goals of the COHERENT experiment is to test the square of the neutron number dependence of the CEvNS cross section predicted in the Standard Model by observing CEvNS in multiple nuclei. To that end, the ~24 kg CENNS-10 liquid argon detector was deployed at the low-background Neutrino Alley at the SNS in early 2017. The detector was upgraded to allow for sensitivity to CEvNS in mid-2017. We analyzed 1.5 years of data taken after this upgrade to provide the first detection of CEvNS on an argon nucleus at > 3$\sigma$ significance. The measured CEvNS cross section of (2.3$\pm$0.7) x 10$^{39}$cm$^2$, averaged over the incident neutrino flux, is consistent with the Standard Model prediction. This result represents a detection of CEvNS on the lightest nuclei so far and improves bounds on beyond-the-standard-model physics in the form of non-standard neutrino interactions

Nd:YAG development for spaceborne laser ranging system

The results of the development of a unique modelocked laser device to be utilized in future NASA space-based, ultraprecision laser ranger systems are summarized. The engineering breadboard constructed proved the feasibility of the pump-pulsed, actively modelocked, PTM Q-switched Nd:YAG laser concept for the generation of subnanosecond pulses suitable for ultra-precision ranging. The laser breadboard also included a double-pass Nd:YAG amplifier and provision for a Type II KD*P frequency doubler. The specific technical accomplishment was the generation of single 150 psec, 20-mJ pulses at 10 pps at a wavelength of 1.064 micrometers with 25 dB suppression of pre-and post-pulses

Real-time Likelihood Methods for Improved Gamma-ray Transient Detection and Localization

We present a maximum likelihood (ML) algorithm that is fast enough to detect gamma-ray transients in real time on low-performance processors often used for space applications. We validate the routine with simulations and find that, relative to algorithms based on excess counts, the ML method is nearly twice as sensitive, allowing detection of 240-280% more short gamma-ray bursts. We characterize a reference implementation of the code, estimating its computational complexity and benchmarking it on a range of processors. We exercise the reference implementation on archival data from the Fermi Gamma-ray Burst Monitor (GBM), verifying the sensitivity improvements. In particular, we show that the ML algorithm would have detected GRB 170817A even if it had been nearly four times fainter. We present an ad hoc but effective scheme for discriminating transients associated with background variations. We show that the on-board localizations generated by ML are accurate, but that refined off-line localizations require a detector response matrix with about ten times finer resolution than is current practice. Increasing the resolution of the GBM response matrix could substantially reduce the few-degree systematic uncertainty observed in the localizations of bright bursts.Comment: 18 pages, 11 figure

AUX: A scripting language for auditory signal processing and software packages for psychoacoustic experiments and education

This article introduces AUX (AUditory syntaX), a scripting syntax specifically designed to describe auditory signals and processing, to the members of the behavioral research community. The syntax is based on descriptive function names and intuitive operators suitable for researchers and students without substantial training in programming, who wish to generate and examine sound signals using a written script. In this article, the essence of AUX is discussed and practical examples of AUX scripts specifying various signals are illustrated. Additionally, two accompanying Windows-based programs and development libraries are described. AUX Viewer is a program that generates, visualizes, and plays sounds specified in AUX. AUX Viewer can also be used for class demonstrations or presentations. Another program, Psycon, allows a wide range of sound signals to be used as stimuli in common psychophysical testing paradigms, such as the adaptive procedure, the method of constant stimuli, and the method of adjustment. AUX Library is also provided, so that researchers can develop their own programs utilizing AUX. The philosophical basis of AUX is to separate signal generation from the user interface needed for experiments. AUX scripts are portable and reusable; they can be shared by other researchers, regardless of differences in actual AUX-based programs, and reused for future experiments. In short, the use of AUX can be potentially beneficial to all members of the research community—both those with programming backgrounds and those without