Shawn Patrick McKee

Cosmic-ray positrons: Are there primary sources?

Abstract Galactic cosmic rays consist of primary and secondary particles. Primary cosmic rays are thought to be energized by first order Fermi acceleration processes at supernova shock fronts within our Galaxy. The cosmic rays that eventually reach the Earth from this source are mainly protons and atomic nuclei, but also include electrons. Secondary cosmic rays are created in collisions of primary particles with the diffuse interstellar gas. They are relatively rare but carry important information on the Galactic propagation of the primary particles. The secondary component includes a small fraction of antimatter particles, positrons and antiprotons. In addition, positrons and antiprotons may also come from unusual sources and possibly provide insight into new physics. For instance, the annihilation of heavy supersymmetric dark matter particles within the Galactic halo could lead to positrons or antiprotons with distinctive energy signatures. With the High-Energy Antimatter Telescope (HEAT) balloon-borne instrument, we have measured the abundances of positrons and electrons at energies between 1 and 50 GeV. The data suggest that indeed a small additional antimatter component may be present that cannot be explained by a purely secondary production mechanism. Here we describe the signature of the effect and discuss its possible origin.

TeraPaths: End-to-End Network Path QoS Configuration Using Cross-Domain Reservation Negotiation

TeraPaths is a DOE MICS/SciDAC-fundedproject conceived to address the needs of the high energy and nuclear physics scientific community for effectively protecting data flows of various levels of priority through modern high-speed networks. TeraPaths is rapidly evolving from a last-mile, LAN QoS provider to a distributed end-to-end network path QoS negotiator through multiple administrative domains. Developed as a web service-based software system, TeraPaths automates the establishment of network paths with QoS guarantees between end sites by configuring their corresponding LANs and requesting MPLS paths through WANs on behalf of end users. The primary mechanism for the creation of such paths is the negotiation and placement of advance reservations across all involved domains. This paper describes the status of the project, our experiences so far, as well as the directions of our continued work.

StorNet: Co-scheduling of end-to-end bandwidth reservation on storage and network systems for high-performance data transfers

Modern scientific data-intensive applications brought about the need for novel data transfer technologies and automated tools capable of effectively utilizing available raw network bandwidth and intelligently assisting scientists in replicating large volumes of data to desired locations in a timely manner. In this paper we describe the design of StorNet, an integrated end-to-end resource provisioning and management system for high performance data transfers that can operate with heterogeneous network protocols and storage systems in a federated computing environment. StorNet allocates and co-schedules storage and network resources involved in data transfers. It is based on existing Storage Resource Manager, TeraPaths, and OSCARS capabilities. StorNet provides data intensive applications with the capability of predictable, yet efficient delivery of data at rates of multiple gigabits/second, bridging end-to-end advanced storage and network technologies in a transparent way.

SNAP telescope: an update

We present the baseline telescope design for the telescope for the SuperNova/Acceleration Probe (SNAP) space mission. SNAP’s purpose is to determine expansion history of the Universe by measuring the redshifts, magnitudes, and spectral classifications of thousands of supernovae with unprecedented accuracy. Discovering and measuring these supernovae demand both a wide optical field and a high sensitivity throughout the visible and near IR wavebands. We have adopted the annular-field three-mirror anastigmat (TMA) telescope configuration, whose classical aberrations (including chromatic) are zero. We show a preliminary optmechanical design that includes important features for stray light control and on-orbit adjustment and alignment of the optics. We briefly discuss stray light and tolerance issues, and present a preliminary wavefront error budget for the SNAP Telescope. We conclude by describing some of the design tasks being carried out during the current SNAP research and development phase.

The DYNES Instrument: A Description and Overview

Scientific innovation continues to increase requirements for the computing and networking infrastructures of the world. Collaborative partners, instrumentation, storage, and processing facilities are often geographically and topologically separated, as is the case with LHC virtual organizations. These separations challenge the technology used to interconnect available resources, often delivered by Research and Education (RE a delicate balance is required to serve both long-lived, high capacity network flows, as well as more traditional end-user activities. The advent of dynamic circuit services, a technology that enables the creation of variable duration, guaranteed bandwidth networking channels, allows for the efficient use of common network infrastructures. These gains are seen particularly in locations where overall capacity is scarce compared to the (sustained peak) needs of user communities. Related efforts, including those of the LHCOPN [3] operations group and the emerging LHCONE [4] project, may take advantage of available resources by designating specific network activities as a “high priority”, allowing reservation of dedicated bandwidth or optimizing for deadline scheduling and predicable delivery patterns. This paper presents the DYNES instrument, an NSF funded cyberinfrastructure project designed to facilitate end-to-end dynamic circuit services [2]. This combination of hardware and software innovation is being deployed across R&E networks in the United States at selected end-sites located on University Campuses. DYNES is peering with international efforts in other countries using similar solutions, and is increasing the reach of this emerging technology. This global data movement solution could be integrated into computing paradigms such as cloud and grid computing platforms, and through the use of APIs can be integrated into existing data movement software.

StorNet: Integrated Dynamic Storage and Network Resource Provisioning and Management for Automated Data Transfers

StorNet is a joint project of Brookhaven National Laboratory (BNL) and Lawrence Berkeley National Laboratory (LBNL) to research, design, and develop an integrated end-to-end resource provisioning and management framework for high-performance data transfers. The StorNet framework leverages heterogeneous network protocols and storage types in a federated computing environment to provide the capability of predictable, efficient delivery of high-bandwidth data transfers for data intensive applications. The framework incorporates functional modules to perform such data transfers through storage and network bandwidth co-scheduling, storage and network resource provisioning, and performance monitoring, and is based on LBNLs BeStMan/SRM, BNLs TeraPaths, and ESNets OSCARS systems.

The TeraPaths Testbed: Exploring End-to-End Network QoS

The TeraPaths project at Brookhaven National Laboratory (BNL) investigates the combination of DiffServ-based LAN QoS with WAN MPLS tunnels in creating end-to-end (host-to-host) virtual paths with bandwidth guarantees. These virtual paths prioritize, protect, and throttle network flows in accordance with site agreements and user requests, and prevent the disruptive effects that conventional network flows can cause in one another. This paper focuses on the TeraPaths testbed, a collection of end-site subnets connected through high-performance WANs, serving the research and software development needs of the TeraPaths project. The testbed is rapidly evolving towards a multiple end-site infrastructure, dedicated to QoS networking research, and it offers unique opportunities for experimentation with minimal or no impact on regular, production networking operations.

Wide-Field Surveys from the SNAP Mission

The Supernova / Acceleration Probe (SNAP) is a proposed space-borne observatory that will survey the sky with a wide-field optical/near-infrared (NIR) imager. The images produced by SNAP will have an unprecedented combination of depth, solid-angle, angular resolution, and temporal sampling. For 16 months each, two 7.5 square-degree fields will be observed every four days to a magnitude depth of AB=27.7 in each of the SNAP filters, spanning 3500-17000Å. Co-adding images over all epochs will give AB=30.3 per filter. In addition, a 300 square-degree field will be surveyed to AB=28 per filter, with no repeated temporal sampling. Although the survey strategy is tailored for supernova and weak gravitational lensing observations, the resulting data will support a broad range of auxiliary science programs.

Scientific data movement enabled by the DYNES instrument

Scientific innovation continues to increase requirements for the computing and networking infrastructures of the world. Collaborative partners, instrumentation, storage, and processing facilities are often geographically and topologically separated, thus complicating the problem of end-to-end data management. Networking solutions, provided by R&E focused organizations, often serve as a vital link between these distributed components. Capacity and traffic management are key concerns of these network operators; a delicate balance is required to serve both long-lived, high capacity network flows, as well as more traditional end-user activities. The advent of dynamic circuit services, a technology that enables the creation of variable duration, guaranteed bandwidth networking channels, has afforded operations staff greater control over traffic demands and has increased the overall quality of service for scientific users. This paper presents the DYNES instrument, an NSF funded cyberinfrastructure project designed to facilitate end-to-end dynamic circuit services. This combination of hardware and software innovation is being deployed across R&E networks in the United States, end sites located at University Campuses. DYNES is peering with international efforts in other countries using similar solutions, and is increasing the reach of this emerging technology. This global data movement solution could be integrated into computing paradigms such as cloud and grid computing platforms, and through the use of APIs can be integrated into existing data movement software.

The UltraLight Project: The Network as an Integrated and Managed Resource for Data-Intensive Science

Looks at the UltraLight project which treats the network interconnecting globally distributed data sets as a dynamic, configurable, and closely monitored resource to construct a next-generation system that can meet the high-energy physics communitys data-processing, distribution, access, and analysis needs.