Radionuclide detection by ion-chromatography and on-line ICP/MS and beta detection: Fission product rare earth element measurements

Separation and analysis of²³⁵U fission produced rare earth elements (REE) is described. Rare earth elements were separated using a high presure ion chromatographic separation where by each rare earth is isolated and individually detected. Detection is performed by inductively coupled plasma mass spectrometry (ICP/MS) and solid scintillation beta counting. The resulting detection methods allow complete evaluation of all stable (non-radioactive) and many radioactive REE fission products. The two detection methods (ICP/MS and Beta) illustrate how mass selective and radiometric data can be used to provide complimentary information regarding the isotopic characterization of radioactive samples.Pacific Northwest Laboratory is operated for the U.S. Department of Energy by Battelle Memorial Institute under Contract DE-AC06-76RLO 1830.     

The effect of pulsed electric fields on biological cells:experiments and applications

The effect of pulsed electric fields with amplitudes in the range of 100 V/cm-100 kV/cm on bacteria and aquatic nuisance species has been explored. The pulse duration was so short that heating of the biological matter could be neglected. The electrical energy required for lysing of bacteria, or stunning of aquatic species, decreases when the pulse duration is reduced. For lysing of Eschericia coli, this tendency has been proven to hold for pulsewidths as short as 60 ns. For macroorganisms, however, it was found that for pulsewidths of less than 5 μs, the tendency is reversed: the energy required to affect the macroorganisms increases again. This minimum in energy, or maximum in efficiency, respectively, can be understood by taking the time required for electrical charging of the cell membrane into account. Applications of the pulsed electric field technique (PEFT) are in biofouling prevention, debacterialization of liquids, and in the field of medicine. A series of field tests on biofouling prevention in a cooling system with untreated water as coolant has demonstrated the economic feasibility of the electro-technology     

A cryogenic underground observatory for rare events: CUORE, an update

CUORE is a proposed tightly packed array of 1000 TeO₂ bolometers, each being a cube 5 cm on a side with a mass of 750 g. The array consists of 25 vertical towers, arranged in a square of 5 towers by 5 towers, each containing ten layers of four crystals. The design of the detector is optimized for ultralow-background searches for neutrinoless double beta decay of ¹³⁰Te (33.8% abundance), cold dark matter, solar axions, and rare nuclear decays. A preliminary experiment involving 20 crystals of various sizes (MIBETA) has been completed, and a single CUORE tower is being constructed as a smaller scale experiment called CUORICINO. The expected performance and sensitivity, based on Monte Carlo simulations and extrapolations of present results, are reported.     

Absence of Charge-Resonance-Enhanced Ionization in Attosecond Pulse Photoionization： Numerical Result on One-Dimensional H2^＋

We present a numerical result of photoionization rate for the one-dimensional molecular hydrogen ion model exposed to intense light of 1 × 10^16-2×10^16 W/cm^2, 55-as pulse duration, and 800nm wavelength. In contrast to the previous calculation result of charge-resonance-enhanced ionization for lower intensity and much longer pulse, our result exhibits an ionization saturation. The numerical results are interpreted in the field-dressed potential picture as over-the-barrier liberation of electrons. This extremely short pulsewidth and relatively high field phenomenon requests experimental demonstration.     

Operation of repetitively pulsed virtual cathode oscillators on theTEMPO pulser

The design and performance characteristics of two virtual cathode oscillators operated at a 1-Hz repetition rate for a 10-shot burst using the TEMPO pulser are presented. The 2.4-GHz hardware generated a 300 MW per pulse (radiated) in the TM₀₂ mode with a 1.3% total energy conversion efficiency and with a 10.5% frequency bandwidth. A 2:1 scale-tip of this hardware was used to achieve an 840-MHz operation, but it only radiated 70 MW per pulse in the TM₀₁ mode with a 7.3% bandwidth, since hardware constraints prevented the TM₀₂ component from being radiated. The relatively low beam current density of the TEMPO VCOs yielded a low diode gap closure rate that should make them suitable for long-pulse operation. In addition, the low beam current density minimized damage to the thin anode screen     

A study of mixed mode fracture by photoelasticity and digital image analysis

In this paper, the results from two experimental methodologies, photoelasticity aided by digital image processing and precision digital image correlation, are presented for a mixed mode fracture problem. The mixed mode fracture problem was a three-point-bend edge-crack specimen which was loaded at various off-crack-line locations between the crack line and the specimen support line. The estimations of K_I and K_II from both methodologies indicate that the crack tip stress field is strongly intensified by K_I but not K_II.