Results for “HfVP” | Engineering Papers

DOE OSTI2020

Materials Data on HfVP by Materials Project

HfVP crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Hf is bonded in a 5-coordinate geometry to five equivalent P atoms. There are a spread of Hf–P bond distances ranging from 2.64–2.81 Å. V is bonded in a 4-coordinate geometry to four equivalent P atoms. There are a spread of V–P bond distances ranging from 2.43–2.54 Å. P is bonded in a 9-coordinate geometry to five equivalent Hf and four equivalent V atoms.

36 MATERIALS SCIENCE↗

NASA NTRS2008

The Hertz/VPM Polarimeter: Design and First Light Observations

We present first results of Hertz/VPM, the first submillimeter polarimeter employing the dual Variable-delay Polarization Modulator (dual-VPM). This device differs from previously used polarization modulators in that it, operates in translation rather than mechanical rotation. We discuss the basic theory behind this device, and its potential advantages over the commonly used half wave plate (HFVP). The dual-VPM was tested both at the Submillimeter Telescope Observatory (SMTO) and in the lab. In each case we present a detailed description of the setup. We discovered nonideal behavior in the system. This is at least in part due to properties of the VPM wire grids (diameter, spacing) employed in our experiment. Despite this, we found that the dual-VPM system is robust, operating with high efficiency and low instrumental polarization. This device is well suited for air and space-borne applications.

Krejny, Megan↗