Future Prospects for High Energy Polarimetry of Gamma‐Ray Bursts

The recent detection of linear polarization from GRB120206 has piqued the interest of the community in this relatively unexplored avenue of research. Here, we review the current status and prospects for GRB polarimetry at hard X‐ray and soft γ‐ray energies. After reviewing the most recent results, we present a brief survey of current and planned experiments that are capable of making GRB polarization measurements in the energy range between 30 keV and 30 MeV

An overview of solar flare results from COMPTEL

The COMPTEL experiment on the Compton Gamma Ray Observatory (CGRO) has been operating in orbit since April of 1991. During that time, COMPTEL has observed several large flares, the most notable of which were several X‐class flares which took place in June of 1991. As a solar instrument, COMPTEL has the capability to measure solar flare radiation in two parallel observing modes. In its telescope mode, COMPTEL is capable of measuring both solar flare photons (in the 0.75–30 MeV range) and solar flare neutrons (in the 20–150 MeV range) using the double scatter technique with a field‐of‐view of ∼1 steradian. This approach also permits the imaging of the incident solar radiations (both photons and neutrons). The burst mode of COMPTEL utilizes two of the lower D2 detectors as large‐area spectroscopy detectors to provide additional data in the 0.6–10 MeV range. Here we shall review both modes of COMPTEL operation and provide an overview of solar flare results which are presently available

GRAPE - A Balloon-Borne Gamma-Ray Polarimeter Experiment

This paper reviews the development status of GRAPE (the Gamma-Ray Polarimeter Experiment), a hard X-ray Compton Polarimeter. The purpose of GRAPE is to measure the polarization of hard X-rays in the 50-300 keV energy range. We are particularly interested in X-rays that are emitted from solar flares and gamma-ray bursts (GRBs), although GRAPE could also be employed in the study of other astrophysical sources. Accurately measuring the polarization of the emitted radiation will lead to a better understating of both emission mechanisms and source geometries. The GRAPE design consists of an array of plastic scintillators surrounding a central high-Z crystal scintillator. The azimuthal distribution of photon scatters from the plastic array into the central calorimeter provides a measure of the polarization fraction and polarization angle of the incident radiation. The design of the detector provides sensitivity over a large field-of-view (>pi steradian). The design facilitates the fabrication of large area arrays with minimal deadspace. This paper presents the latest design concept and the most recent results from laboratory tests of a GRAPE science model.Comment: 6 pages; paper presented at the FRASCATI Workshop 2005 on Multifrequency Behaviour of High Energy Cosmic Sources; submitted to Chinese Journal of Astronomy and Astrophysic

COMPTEL solar flare measurements

We review some of the highlights of the COMPTEL measurements of solar flares. These include images of the Sun in γ rays and neutrons. One of the important features of the COMPTEL instrument is its capability to measure weak fluxes of γ rays and neutrons in the extended phase of flares. These data complement the spectra taken with the COMPTEL burst spectrometer and the telescope during the impulsive phase of flares. We focus our attention on some of these general capabilities of the instrument and the latest results of two long‐duration γ‐ray flares, i.e., 11 and 15 June 199

Assessment and treatment of disruptive behavior maintained by escape from dental procedures for individuals with autism

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A General Correction For Spontaneous Potential Well Logs In Fresh Water

A generalized empirical relationship was found which corrects spontaneous potential (SP) readings from well logs run in freshwater wells. The function was found by correlating measured and calculated spontaneous potentials. The calculated values are based on actual measured ionic content of groundwaters and are fully corrected for environmental effects and ion species. Without the empirical relationship the electrically equivalent to an NaCl solution resistivity, Rwe, is generally too low for fresh waters when computed with existing commercially available functions. The low Rwe makes the water appear saltier than it really is. One hundred sixty-two (162) individual formations from one hundred four (104) different shallow well logs from widely separated regions of the United States and different types of aquifers were examined. Each formation used in the study had to have a spontaneous potential, mud resistivity data, a chemical analysis of water from the zone, and not be in communication with other zones. Every SP had the existing commercially available geometric corrections applied. A computer program was developed which computes a simulated SP from the chemical analysis and mud data. This simulated SP was plotted against the measured SP. The resulting relationship is given by: MEASURED SP=0.3782 x SIMULATED SP + 6.9172. for 0 mv \u3c SIMULATED SP \u3c + 50 mv. This type of relationship is consistent with earlier work by the author in a localized area. The function can only be applied in fresh waters with simulated SPs in the indicated domain since simulated and measured SPs converge in brine formations. © 1988

An Approach for Optimizing the On-Orbit Servicing Architecture for the Space-Based Radar Constellation

Satellite systems, once operational, are essentially a consumable item with no capacity to maintain, repair, or upgrade them while on-orbit. In order to avoid having to replace costly space assets, the Defense Advanced Research Projects Agency (DARPA) and Air Force Space Command (AFSPC) are looking to developing programs to provide an on-orbit servicing capability for future satellite systems under development, such as the Space-Based Radar (SBR) system. DARPA and AFSPC are studying on-orbit servicing using the Orbital Express platform as part of an Analysis of Alternatives for the SBR program. Like their satellite clients, on-orbit servicing assets are expected to be resource intensive, and so proper management of these space logistics assets is essential. This research provides a flexible planning tool to determine the optimal on-orbit servicing architecture for a given client satellite constellation and applies it to the proposed SBR constellation. The model uses a generalized network structure with side constraints to efficiently solve this large combinatorial optimization problem. The optimal number and type of servicing vehicles to use is found, along with the associated most efficient routing to meet client satellite demand for two commodities within multiple time windows