No abstract

The use of rotational Raman scattering for nondestructive analysis of laser fusion microsphere targets is reported. Typical hollow-glass-microsphere sample characteristics are 100 μm in diameter, 1.0 μm in glass wall thickness, and 0.5 nl in volume, containing a mixture of hydrogen, deuterium, and tritium gases at pressures of 10–70 atm (total gas sample weights of 5 ng). Relative species mole fraction measurements for all hydrogen isotope species are determined from spectral peak height analysis of rotational Raman spectra. Accuracies of ±0.01 (mole fraction) are obtained from spectra requiring 20 min scan time. Individual species detectability limits are less than 100 picogram. Absolute partial pressure measurements (accurate to ±20%) are obtained using calibration spheres of known diameter and pressure.

We measured the permeability of inertial fusion (IF) fuel shells made of poly(vinyl alcohol) (PVA) and polystyrene (PS) with deuterium. Activation energies of permeation (Ep̄) were determined using permeability coefficients measured over the temperature range 25–100 °C for PVA, and −100 to 25 °C for PS shells. We then exposed this same batch of shells to intense beta irradiation from tritium and repeated the permeation measurements. Comparing permeabilities of the same shells before and after irradiation, we obtained a measure of the effect beta irradiation has on fuel retention characteristics of the polymers. Our results show that irradiation does change the permeability of PVA, while the permeability of irradiated PS is relatively unchanged.

Thermogravimetric studies of divalent metal chelates of eight common amino acids have revealed that no relationship exists between thermal stability orders of the chelates and hydrolytic stability orders, infrared band shifts or force constants. An attempt is made to relate thermal stability order to relative heats of formation and stereochemistry.Amino acid chelates have been studied extensively during the last two decades. A variety of instrumental techniques have been used. Their thermal stabilities, however, have not been studied in any detail.Most thermal stability work has been directed at the amino acids themselves, determining decomposition temperatures [1--3] and products of decomposition [4,5]. Differential thermal analysis curves for copper glycinate mono-and dihydrate [6], cadmium glycinate monohydrate [7] and copper alaninate monohydrate [8] have been published, along with thermogravimetric curves for copper complexes of glycine and ~-alanine [9] and cobalt(III) complexes of glycine, e-alanine and leucine [10]. It has been noted [2] that aliphatic amino acids are more stable when they have short, linear alkyl side chains rather than long branched chains. Other than this, however, no attempt has been made to correlate thermal stabilities with other structural or chemical properties.Since a number of amino acid chelates were still easily available to us, it was decided to study the thermal properties of the compounds. Accordingly, thermogravimetric data for divalent transition metal chelates of glycine, DL-~-alanine, DL-fl-alanine, DL-serine, DL-c~-amino-n-butyric acid, DL-~-aminoisobutyric acid, DL-norvaline and DL-leucine were obtained. The resulting thermal data might then be compared with other available information such as infrared data and hydrolytic stability constants of amino acid chelates and thermal stabilities of other complexes of these transition metals.

Quantitative measurements of deuterium partial pressures in laser fusion targets are made by inverse Raman spectroscopy. Attenuation of atmospheric nitrogen inverse Raman signals is used for standardization of the system. This technique allows calibration curves to be made with long path gas cells. The measurements are accurate to ±20%.