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The ε(0,0) (D [sup 2]Σ[sup +]–X [sup 2]Π[sub r]) band of NO has been recorded by using a vacuum ultraviolet Fourier transform spectrometer from Imperial College, London, with synchrotron radiation at the Photon Factory, KEK, Japan, as a continuum light source. Analysis of the ε(0,0) band provides accurate rotational line positions and term values as well as the photoabsorption cross sections. Molecular constants of the v=0 level of the D [sup 2]Σ state have been determined as T[sub 0]=53 291.10±0.10 cm[sup -1], B[sub 0]=1.991 07±0.000 05 cm[sup -1], and D[sub 0]=(6.6±0.1)×10[sup -6] cm[sup -1]. Accurate rotational line strengths have also been obtained and the sum of the line strengths for all rotational lines is determined as 2.18×10[sup -15] cm[sup 2] cm[sup -1]. The band oscillator strength of the ε(0,0) band is determined to be (2.47±0.12)×10[sup -3]. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The β(6,0) (B [sup 2]Π[sub r]–X [sup 2]Π[sub r]) and γ(3,0) (A [sup 2]Σ[sup +]–X [sup 2]Π[sub r]) bands of NO have been recorded using a vacuum ultraviolet Fourier transform spectrometer with synchrotron radiation as light source. The analysis of the β(6,0) and γ(3,0) bands of NO provides accurate rotational line positions and term values. Molecular constants of the v=6 level of the B [sup 2]Π[sub r] and v=3 level of the A [sup 2]Σ[sup +] have been determined. Accurate rotational line strengths have also been obtained. The band oscillator strength of the β(6,0) and γ(3,0) bands are determined to be 0.48×10[sup -4] and 2.69×10[sup -4], respectively. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]

A general formula is found to predict thermoluminescence emission over a wide range of heating profiles. This is particularly useful for rapid laser heating which generates very nonlinear temperature-time profiles. Special cases of the general formula are considered for power-law and logarithmic temperature-time curves. The results compare well to previous CO[sub 2] laser heated thermoluminescence experiments. The agreement between theory and experiment extends over several orders of magnitude change in the heating rate. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The dynamics of debris in a buffer gas after ejection from the solid target during laser-plasma soft x-ray generation is studied. Analytical formulas for the flight range of cylindrical and spherical debris are derived using the incompressible flow theory. The validity range of the formulas and the related error margins are discussed. Finally, the flight range formula for spherical particles is extended to two times the Mach number at the expenses of a somewhat higher error margin (up to 25%). © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Focuses on a study conduted using simplified kinetic models to investigate the mechanism of negative differential conductivity (NDC) in an electron-beam sustained gas discharge of pure xenon (Xe). Calculation of the drift velocity of electrons in Xe; What model calculations involves; Definition of NDC; Discussion on the influence of the uncertainty in the momentum transfer cross sections and the small impurity of Xe on NDC observation.

Presents information on a study which described the use of thermal deposition of silicon[sub2]hydrogen[sub6] in a hydrogen or helium flow for the deposition of alpha-silicon:hydrogen films on Corning 7059 glass substrates. Deposition of the films; Electrical conductivity of the films.

A Texas Nuclear Cockcroft-Walton neutron generator was refurbished for use as a general fusion-product source. This well-calibrated source is now used routinely for characterizing energetic charged-particle detectors, for the development of nuclear fusion diagnostics, for studying radiation damage, and for calibrating x-ray detectors for laboratory and space plasmas. This paper is an overview of the facility. We describe the main accelerator operating systems, the primary fusion reactions studied, and several diagnostics used to characterize the fusion-product source. [ABSTRACT FROM AUTHOR]

As part of an on-going effort to develop diagnostics for energetic charged particles from laboratory and space experiments, we examined the possibility that particle identification could be expedited by varying the applied bias voltage on silicon surface barrier detectors (SBDs). Using MeV protons, tritons, and alphas, we performed spectroscopy experiments whereby we observed changes of the energy spectrum as a function of the bias voltage. These particles were either generated via a Coekcroft-Walton linac as fusion products, or emitted from radioisotopes. The results indicate that, contrary to commonly held belief, the detector sensitive depth is not generally the depletion depth. Indeed for partially depleted SBDs the performance is not greatly degraded even for zero bias. [ABSTRACT FROM AUTHOR]

The first demonstrated achievement of p on n-type activated junctions in HgCdTe material by arsenic ion implantation is reported. The junctions were formed by treating the implant as a finite diffusion source in the post-implant anneals. The materials employed for this study were n-type indium impurity-doped liquid phase epitaxy HgCdTe grown on CdTe. Arsenic was selected as the candidate acceptor impurity since it activated during post-implanted anneals in Hg vapor. The arsenic concentration profile determined by secondary ion mass spectroscopy showed that during post-implant anneal a complex diffusion mechanism redistributes the arsenic. The activation efficiency appears to be mechanism dependent. In the junction region the implant activation efficiency is about 50%. Junction depth can be controlled by varying arsenic diffusion and background carrier concentration. Junction depths determined by the electron beam induced current technique were consistent with the differential Hall electrical profiles. A p on n junction is shown with excellent rectification characteristics and high breakdown voltage (sharp at 2.5 V and 77 °C). This was obtained from a liquid phase epitaxy Hg1-xCdxTe, with a compositional factor of x=0.23. [ABSTRACT FROM AUTHOR]

With a plasma current of up to 3 MA, toroidal field of up to 9 T, the confinement of the charged fusion products (CFPs) in Alcator C-Mod is expected to be excellent. For example, at maximum current and field, classical losses of the 0.8 MeV ³He, 1 MeV triton, 3 MeV proton, 3.5 and 3.7 MeV alphas are expected to be less than 5%. For the study of the global confinement of CFPs, we plan to measure the burnup of the 1 MeV triton (from the D-D reaction) using a proton recoil detector (NE-213) for the detection of the 14 MeV neutron resulting from the secondary fusion reaction (D-T). On the other hand, loss measurements of CFPs will be made inside the first wall with two detectors (one at the bottom, one at the midplane) using silicon based detectors. The midplane detector will be used to diagnose D-³He plasmas by looking at the unconfined 14.7 MeV proton. In addition to the derivation of fusion yield, energy distribution of the escaping protons will provide information about the ion velocity distribution of the reactants. The bottom detector is time, pitch angle and energy resolved, and thus will be used to study loss mechanisms such as first orbit, toroidal field ripple and magnetohydrodynamics-induced diffusion. [ABSTRACT FROM AUTHOR]

Two new x-ray source systems are now on line at our facility. Each provides an e-beam to 25 kV. Targets are interchangeable between machines, and four x-ray detectors may be used simultaneously with a target. The gridded e-gun of the RACEHORSE system gives a 0.5-1.0-cm pulsable spot on target. The nongridded e-gun of the SCORPION system provides a 0.3-mm or smaller dc microspot on target. RACEHORSE is being used to study and characterize type-II diamond photoconductors for use in diagnosing plasmas, while SCORPION is being used to develop a slitless spectrograph using photographic film. Source design details and some RACEHORSE results are presented. [ABSTRACT FROM AUTHOR]

In conjunction with γ-ray diagnostic development for the NOVA Upgrade and Alcator C-MOD experiments, we have assembled a comprehensive set of absolutely calibrated γ-ray sources and several γ-ray detectors. These tools will be used in characterizing and calibrating new γ-ray diagnostic systems as they are assembled. The γ-ray sources comprise both radioisotopes and nuclear reactions. The latter are generated in the MIT Cockcroft-Walton fusion-product generator. The detectors include several "standard" NaI(T1) scintillators and a high-resolution germanium detector. This paper briefly discusses the diagnostics planned for NOVA Upgrade and Alcator C-MOD. In addition it describes the γ-ray sources and detector characterizations we have performed in the laboratory. [ABSTRACT FROM AUTHOR]

We are developing activation diagnostics for monitoring energetic charged-particle fluxes in space and laboratory plasmas. More immediately, we plan to use activation to measure the time-integrated proton flux from D-³He fusion reactions in Alcator C-MOD, providing a measure of the time-averaged D-³He fusion rate. We demonstrated the technique's feasibility by inducing significant gamma activity in a titanium sample exposed to D-³He protons created in our Cockcroft-Walton generator. The titanium target received a fluence of 5.5 × 10[sup 9] protons at 14.7 MeV (of order what a 3-cm² target should receive from one shot in Alcator C-MOD) and became activated by the [sup 48]Ti(p,n)[sup 48]V reaction. The activity's spectrum from a high-purity germanium (HPGe) detector showed the characteristic 0.984- and 1.312-MeV lines of [sup 48]V. The measured activity agreed reasonably well with theory. An absence of activity at those energies before D-³He activation eliminated background or D-D product-induced activity as the gamma source. We intend to repeat the experiment with a chromium target to evaluate that material's diagnostic potential. [ABSTRACT FROM AUTHOR]

A high-intensity, charged-particle-induced x-ray (PIXE) source has been developed for the purpose of characterizing x-ray detectors and optics, and measuring filter transmissions. With energetic proton beams up to 165 keV, intense line x radiations (0.5 Å≤λ≤111 Å) have been generated from the K, L, M, and N shells of elements 4≤Z≤92. The PIXE spectrum has orders-of-magnitude lower background continuum than a conventional electron beam or radioactive α-fluorescence source [C. K. Li, R. D. Petrasso, K. W. Wenzel et al. (to be published)]. [ABSTRACT FROM AUTHOR]

A combination of organometallic and isothermal vapor phase epitaxy was used sequentially to grow CdTe and Hg[sub 1-x]Cd[sub x] Te on GaAs substrates. Photodiodes in the Hg[sub 1-x] Cd[sub x]Te show properties comparable to the best Hg[sub 1-x]Cd[sub x] Te grown by liquid phase epitaxy. Resistance-area products were ≥10[sup 7] ω cm[sup 2] and >10[sup 4]ω cm[sup 2] at 77 K for Hg[sub 1-x]Cd[sub x] Te with cut-offwavelength of 3.73 and 5.54 µm at 77 K, respectively. The backside-illuminated spectral response was broadband with peak external quantum efficiencies typically >50% (without antireflection coating). [ABSTRACT FROM AUTHOR]

A correction to the article "Novel in situ normal streaming potential device for characterizing electrostatic properties of confluent cells," that was published in the August 24, 2012 issue is presented.

The characteristics of transport across confluent cell monolayers may often be attributed to its electrostatic properties. While tangential streaming potential is often used to quantify these electrostatic properties, this method is not effective for transport normal to the apical cell surface where the charge properties along the basolateral sides may be important (i.e., confluent cells with leaky tight junctions). In addition, even when cells have a uniform charge distribution, the shear stress generated by the conventional tangential flow device may dislodge cells from their confluent state. Here we introduce a novel streaming potential measurement device to characterize the normal electrostatic properties of confluent cells. The streaming potential device encompasses a 24 mm cell-seeded Transwell® with two AgCl electrodes on either side of the cell-seeded Transwell. Phosphate buffered saline is pressurized transversal to the Transwell and the resultant pressure gradient induces a potential difference. Confluent monolayers of HEK and EA926 cells are used as examples. The corresponding zeta potential of the cell-membrane configuration is calculated using the Helmholtz-Smoluchowski equation and the zeta potential of the confluent cell layer is deconvolved from the overall measurements. For these test models, the zeta potential is consistent with that determined using a commercial dispersed-cell device. This novel streaming potential device provides a simple, easy, and cost-effective methodology to determine the normal zeta potential of confluent cells cultured on Transwell systems while keeping the cells intact. Furthermore, its versatility allows periodic measurements of properties of the same cell culture during transient studies. [ABSTRACT FROM AUTHOR]

High-temperature inertial and magnetically confined plasmas are copious emitters of y rays and neutrons. Some γ-ray and neutron reactions of interest are D + He³ → Li[sup 5] + γ (16.7), D + P → He³ + γ (5.5 MeV), D + T → He[sup 5] + γ (16.6 MeV), D + D → He[sup 4] + γ (23 MeV), and D + D → He³ + n (2.45 MeV). In order to test and absolutely calibrate γ-ray and neutron diagnostics for such reactions, we are investigating the feasibility of renovating a Cockcroft-Walton accelerator which resides in our laboratory. We will report on the status of this work. This work was supported by U. S. Department of Energy contract No. DE-AC02-78ET51013. [ABSTRACT FROM AUTHOR]