Search

We have developed a design for a hard X-ray Compton polarimeter operating in the energy range from 50 to 500 keV, which we refer to as GRAPE (Gamma-Ray Polarimeter Experiment). We are currently preparing a balloon payload for a flight from Ft. Sumner, NM in the fall of 2011. Using a large (16-element) array of detector modules, this payload is being designed to search for polarization from known point sources of radiation, namely the Crab and Cygnus X-1. This first flight will not only provide a scientific demonstration of the GRAPE design (by measuring polarization from the Crab nebula), it will also lay the foundation for subsequent long duration balloon flights that will be designed for studying polarization from gamma-ray bursts and solar flares. Here we shall present data from calibration of the first flight module detectors and review the latest payload design.

We have developed a design for a hard X-ray Compton polarimeter operating in the energy range from 50 to 500 keV, which we refer to as GRAPE (Gamma-Ray Polarimeter Experiment). We are currently preparing a balloon payload for a flight from Ft. Sumner, NM in the fall of 2011. Using a large (16-element) array of detector modules, this payload is being designed to search for polarization from known point sources of radiation, namely the Crab and Cygnus X-1. This first flight will not only provide a scientific demonstration of the GRAPE design (by measuring polarization from the Crab nebula), it will also lay the foundation for subsequent long duration balloon flights that will be designed for studying polarization from gamma-ray bursts and solar flares. Here we shall present data from calibration of the first flight module detectors and review the latest payload design.

This report reviews the working principles of the InterOcean S4 electromagnetic current meter and outlines the practical difficulties and engineering solutions to convert these basic principles into a working instrument. Presented are the test procedures and results performed on three production units placing emphasis on the oceanographic user's point of view. These tests, include laboratory, dockside, and both surface and subsurface mooring testsj. S4s are compared to each other to other types of current meters in various intercomparison tests. Results of this evaluation program are next summarized. Also, suggestions for areas of improvement and further developments are made. Finally, recommendations for the developments are made. Finally, recommendations for the acceptance, calibration, and burning in of new instruments conclude the report.