652 research outputs found

    Simulations of the nEDM@SNS light collection system efficiency

    Full text link
    A system for collecting the scintillation light produced by the capture process of ultra-cold neutrons (UCN) on polarized 3^{3}He is discussed and results from simulations of its performance are presented. This system will be implemented in nEDM@SNS, the experiment searching for the neutron electric dipole moment (nEDM) at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory. Simulation results show that the light collection system collects on average 17 photoelectrons per UCN-3^{3}He capture event (sufficient to generate a robust signal), reconstructs the event location in the beam direction to approximately 3 cm accuracy, detects capture events with a high and spatially uniform efficiency (0.95 with 1% variation), and rejects greater than 50% of beta decay background events.Comment: 14 pages, 13 figures. Submitted to Journal of Instrumentatio

    Integrated Flush Air Data Sensing System Modeling for Planetary Entry Guidance with Direct Force Control

    Get PDF
    Flush air data sensing (FADS) systems have been previously used at both Earth and Mars to provide onboard estimates of angle of attack, sideslip angle, and dynamic pressure. However, these FADS data were often not used in an in-the-loop sense to inform the onboard guidance and control systems. A method to integrate FADS-derived density and wind estimates with a numerical predictor-corrector guidance algorithm is presented. The method is demonstrated in a high-fidelity simulation of a human-scale Mars entry vehicle that utilizes a hypersonic inflatable aerodynamic decelerator (HIAD) with direct force control. Effects on guidance commands and state uncertainties both with and without FADS system modeling are presented and discussed

    Large Mass, Entry, Descent and Landing Sensitivity Results for Environmental, Performance, and Design Parameters

    Get PDF
    Landing on Mars has been a challenging task. Past NASA missions have shown resilience to increases in spacecraft mass by scaling back requirements such as landing site altitude, landing site location and arrival time. Knowledge of the partials relating requirements to mass is critical for mission designers to understand so that the project can retain margin throughout the process. Looking forward to new missions that will land 1.5 metric tons or greater, the current level of technology is insufficient, and new technologies will need to be developed. Understanding the sensitivity of these new technologies to requirements is the purpose of this paper

    A Study of the (3-He,t) Charge-Exchange Reaction at E(3-He) = 200 MeV

    Get PDF
    This research was sponsored by the National Science Foundation Grant NSF PHY 87-1440

    Inclusive Soft Pion Production from 12.3 and 17.5 GeV/c Protons on Be, Cu and Au

    Full text link
    Differential cross-sections are presented for the inclusive production of charged pions in the momentum range 0.1 to 1.2 GeV/c in interactions of 12.3 and 17.5 GeV/c protons with Be, Cu, and Au targets. The measurements were made by Experiment 910 at the Alternating Gradient Synchrotron in Brookhaven National Laboratory. The cross-sections are presented as a function of pion total momentum and production polar angle θ\theta with respect to the beam.Comment: 14 pages, 8 figure
    • …
    corecore