A liquid xenon ionization chamber in an all-fluoropolymer vessel

A novel technique has been developed to build vessels for liquid xenon ionization detectors entirely out of ultra-clean fluoropolymer. We describe the advantages in terms of low radioactivity contamination, provide some details of the construction techniques, and show the energy resolution achieved with a prototype all-fluoropolymer ionization detector.Comment: 12 pages, 9 figure

High-pressure rheological analysis of CO2-induced melting point depression and viscosity reduction of poly(ε-caprolactone)

High-pressure rheology has been used to assess the effects of supercritical carbon dioxide (scCO2) on the melting point (Tm) and viscosity of poly (ε-caprolactone) (PCL) over a range of temperatures and pressures up to 300 bar over a wide range of shear rates. Plots of the storage and loss moduli against temperature show a significant shift of Tm to lower temperatures in the presence of CO2, indicating that the polymer crystals melt at temperatures much lower than the ambient pressure Tm. Furthermore, a significant decrease in the viscosity of two PCL grades with different molecular weight (Mn ~ 10 kDa and 80 kDa) was also detected upon increasing the CO2 pressure to 300 bar. Experimental viscosity data were fitted to the Carreau model to quantify the extent of the plasticising effects on the zero-shear viscosity and relaxation time under different conditions. Similar analyses were conducted under high-pressure nitrogen, to compare the effects obtained in the presence of a non-plasticising gas

Role of temperature, solvent and agitation in coal dissolution and liquefaction. Quarterly report, December 1981-February 1982

A Plexiglas reactor was constructed and experiments carried out with three mixer configurations in a sand-water system to determine the best mixer configuration and the minimum rpm to produce uniform conditions during coal dissolution. Coal dissolution experiments on Kentucky No. 9 coal were made with combinations of tetralin and 2-methylnaphthalene to obtain the optimum ratio in the solvent. The effect of ..beta..-naphthol addition to the solvent on the dissolution of Kentucky No. 9 coal was studied. The effect of holding time at 400/sup 0/C on the dissolution of Kentucky No. 9 coal in a solvent containing 46.1 wt % tetralin, 46.1 wt % 2-methylnaphthalene, 2.9 wt % ..gamma..-picoline and 4.9 wt % ..beta..-naphthol was studied