X-ray Analysis

"Alameda Brown Ware and San Francisco Mountain Gray Ware Technology and Economics" addresses topics related to the production and distribution of Alameda Brown Ware and the consumption of San Francisco Mountain Gray Ware as reflected in archaeological collections from 41 sites that date from about A.D. 400 through the early-to-mid A.D. 1100s and which are located along U.S. 89 north of Flagstaff, Arizona. The chapter represents the most successful application of the petrofacies approach to sand temper provenance determination to date, given that the compositional data are evaluated using oxidation/refiring of clay and sherd samples, inductively coupled plasma-mass spectrometry (ICP-MS) analysis, x-ray analysis, and direct evidence of production collected from project area sites. Building on the work of Dean Arnold (1985), included are four tables that summarize ethnographic/ethnoarchaeological data which should prove useful in reconstructing pottery production and distribution systems elsewhere. Table 5.1 reports 64 new distance to clay resource measurements. Table 5.17 reports annual ceramic production rates in 25 potting communities. Table 5.23 summarizes examples of the goods and services exchanged for ceramics. Table 5.24 summarizes 12 distance traveled by foot  to trade pottery measurements.

Particle-Induced X-ray Emission (PIXE) analysis was employed to characterize Hydroxypropyl Methylcellulose (HPMC) polymer film via depth profiling on silicon-based substrates, and compared with Rutherford Backscattering Spectrometry (RBS) results. We utilize the concept that α particle incident energy loss by the polymer film affects the α particle penetration depth into the substrate, and can thus find the areal density of the film by computing the amount of energy loss via comparing the yield of X-ray emitted from a substrate element with and without the polymer film. It is demonstrated in this paper that this method and RBS measurements both yield comparable results for areal densities ranging from 1018 to several 1019 atom/cm2. A collection of techniques including PIXE, RBS, Tapping Mode Atomic Force Microscopy (TMAFM), and Sessile Drop contact angle method were used to compute surface free energy, analyze surface topography and roughness parameters, determine surface composition depth profiling, and to predict the water affinity and condensation behaviors of silicates, phosphosilicates, and other compounds used for high impact resistance vision ware coatings. The visor surface under study is slightly hydrophilic, with root mean square of surface roughness on the order of one nm, and surface wavelength between 200 and 300 nm. Water condensation is manifests itself under sports conditions with raised temperature and humidity. Water condensation can be controlled on such surfaces via polymers adsorption. HPMC polymer surface composition is previously determined via 4.265 MeV 12C(α, α) 12C , 3.045 MeV 16O(α, α)16O nuclear resonance analysis (NRA), and 2.8 MeV elastic recoil detection (ERD) of hydrogen1, and combined with PIXE depth profiling technique as detailed in this work to support the analysis of the surface water affinity and topography and therefore control condensation behavior2. HPMC film between 1018 and 1019 atom/cm2 is found to effectively alter the water condensation pattern and prevents fogging by forming a wetting layer during condensation.

""We have designed and tested a one-meter long X-ray diode based on innovative plasma-cathodes, which exploit commercial spark-plugs as electron emitters. Based on the results of a numerical study, we optimized both diode geometry (e.g., the angle between anode and cathode surfaces, the thickness of Al window) and electrical circuitry (e.g., the capacitance in series to each spark-plug, the peak voltage of the anode) of our X-ray generator. The overall result is a simple and efficient circuitry, giving a total diode current in excess of 2.1 kA with a breakdown voltage of 70 kV, which generates a 50-ns-risetime X-ray pulse with a spatially averaged dosage of up to 6 10-4 Gy when using a Pb-wrapped anode. The double-diode X-ray generator was operated for 1.5  106 shots at a repetition rate of up to 30 Hz, and the lifetime test was interrupted without any fault. During the lifetime test, it was not necessary to adjust any working parameter. At the end of the lifetime test, the X-ray emission uniformity was better than 80% along the longitudinal axis.
This X-ray generator has a lifetime, reliability and cost fitting the requirements of industrial users. Among the broad range of potential applications, this X-ray generator is particularly suitable to ionize discharge pumped gas lasers, like TEA CO2 and excimer lasers, including those operated by X-ray triggered discharges.""

We have tested an X-ray diode working in reflection geometry, which uses commercial spark-plugs as plasma cathode. The results of the characterisation work confirm that the spark-plug plasma cathode is a reliable and long-lifetime electron source for X-ray diodes. After more than 10^6 shots, the X-ray dose, uniformity, and ionisation rate values guarantee an effective preionisation of excimer laser discharges. Owing to both the long lifetime and the substantial absence of maintenance, this X-ray diode seems suitable to preionise commercial gas lasers, such as excimer and TEA CO2 lasers.