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The current interest in returning human exploration to the Moon and Mars makes cost-effective and low-mass health monitoring sensors essential for spacecraft development. In space, there are many surface measurements that are required to monitor the condition of the spacecraft including: surface temperature, radiation dose, and impact. Through the use of tailored phosphors, these conditions can be monitored. Practical space-based phosphor sensors will depend heavily upon research investigating the resistance of phosphors to ionizing radiation and their ability to anneal or 'self-heal' from damage caused by ionizing radiation. For the present research, a group of lutetium orthophosphate (LuP[O.sub.4]) crystals with dopants including europium, erbium, and neodymium were characterized. Cathodoluminescence (CL) testing was performed using the Low Energy Electron system located at the NASA Marshall Space Flight Center in Huntsville, Alabama. The data were collected using an Ocean Optics HR4000 spectrometer and a fiber optic feed-through. Previous research has shown that increases in both beam energy and current density improved the CL fluorescence yield. While the total electron dose was small, the intention was to maximize the number of irradiated materials. Additionally, these samples were evaluated using a PTI Quantum Master Spectropbotometer to determine the photoluminescence emission spectra.

The room temperature phonon spectra of the series of rare earth orthovanadate single crystals were obtained by polarized Raman spectroscopy. The results revealed that the frequency of the internal V[O.sub.4] phonons increased with increasing atomic number and the observed Raman frequencies followed the overall mode distribution of REV[O.sub.4] compounds.

A study of the effects of hydrostatic pressure on the dielectric response of single crystal Cd2Nb2O7 (CNO) is conducted over the temperature range of 80-450 K. Pressure had a relatively weak influence on the various overlapping dielectric relaxations below 200 K, but the results revealed a dipolar relaxation in the 350-400 K region.

The current interest in returning to the Moon and Mars by 2030 makes cost effective and low mass health monitoring sensors essential for spacecraft development. In space, there are many surface measurements that are required to monitor the condition of the spacecraft including: surface temperature, radiation dose, and impact. Through the use of phosphors, these conditions can be monitored. Practical space-based phosphor sensors will depend heavily upon research investigating the resistance of phosphors to ionizing radiation and the ability to anneal or self-heal from damage caused by ionizing radiation. The cathodoluminescence (CL) testing was performed using the low energy electron system located at the NASA Marshall Space Flight Center (MSFC) in Huntsville, Alabama. For the materials tested, several interesting results were observed. For most materials, increases in both beam energy and current density improved the CL fluorescence yield. It was also noted that YAG:Nd,Ce has the greatest near infrared intensity for any of the tested materials. The evaluation of dopant concentration in YP[O.sub.4] :Nd showed minimal differences in spectral shape and intensity. While the total electron dose was small, the intention was to maximize the number of irradiated materials. Index Terms--Cathodoluminescence, radiation damage, yttrium phosphors.

The ion implantation of nearly equal doses of Co and Pt into a single-crystal Al2O3 host followed by thermal annealing leads to the formation of nanoparticles whose phase, structure and physical properties are strongly dependent on the annealing environment. Annealing in ultrahigh-vacuum conditions results in a mixture of phases including CoPt3 and CO3O4 and possibly Co.

LuP[O.sub.4]: Nd and YP[O.sub.4]: Nd represent new and very fast potential scintillator materials. For most types of ionizing excitation, the luminescence of these materials is dominated by an emission band whose maximum intensity occurs at about 192 nm. The origin of this band lies in the fast 5d--4f transitions of the [Nd.sup.3+] ions. An additional contribution due to host-defect emission varies for different samples. These defects appear to be responsible for the limited light yield of LuP[O.sub.4]: Nd. Index Terms--Luminescence, recombination, scintillation.

The determination of a pure ErVO4 crystal at room temperature using Ramon scattering methods is described.

We present results from an ongoing search for inorganic scintillators for x- and gamma- ray detection. We measure the scintillation properties (luminous efficiency, decay time, and emission wavelength) of powdered samples excited by brief x-ray pulses. To find scintillators that are compatible with silicon photodetectors, we have tested over 1,100 samples using a photomultiplier tube with a GaAs:Cs photocathode, which is sensitive to 200-950 nm emissions. Optical filters are used to block emissions that are observable with bialkali PMTs. Several lanthanide and transition metal ions, molecular complexes, and II-VI compounds are known to have strong emissions at wavelengths >500 nm. We find that several compounds exhibit emission intensities comparable to commercial phosphors in the 600-900 nm range, including Eu and Sm doped LuP[O.sub.4], ScP[O.sub.4], and YP[O.sub.4]. Significant emissions are also observed from Tb, Dy, Er, Pr, and Tm doped phosphates, as well as several intrinsic compounds, notably [Hg.sub.2][Cl.sub.2]. Scintillation characteristics of promising compounds (in powdered or small crystal form) are presented.